Sample records for affects understorey plant
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Severe dry winter affects plant phenology and carbon balance of a cork oak woodland understorey
Correia, A. C.; Costa-e-Silva, F.; Dubbert, M.; Piayda, A.; Pereira, J. S.
2016-10-01
Mediterranean climates are prone to a great variation in yearly precipitation. The effects on ecosystem will depend on the severity and timing of droughts. In this study we questioned how an extreme dry winter affects the carbon flux in the understorey of a cork oak woodland? What is the seasonal contribution of understorey vegetation to ecosystem productivity? We used closed-system portable chambers to measure CO2 exchange of the dominant shrub species (Cistus salviifolius, Cistus crispus and Ulex airensis), of the herbaceous layer and on bare soil in a cork oak woodland in central Portugal during the dry winter year of 2012. Shoot growth, leaf shedding, flower and fruit setting, above and belowground plant biomass were measured as well as seasonal leaf water potential. Eddy-covariance and micrometeorological data together with CO2 exchange measurements were used to access the understorey species contribution to ecosystem gross primary productivity (GPP). The herbaceous layer productivity was severely affected by the dry winter, with half of the yearly maximum aboveground biomass in comparison with the 6 years site average. The semi-deciduous and evergreen shrubs showed desynchronized phenophases and lagged carbon uptake maxima. Whereas shallow-root shrubs exhibited opportunistic characteristics in exploiting the understorey light and water resources, deep rooted shrubs showed better water status but considerably lower assimilation rates. The contribution of understorey vegetation to ecosystem GPP was lower during summer with 14% and maximum during late spring, concomitantly with the lowest tree productivity due to tree canopy renewal. The herbaceous vegetation contribution to ecosystem GPP never exceeded 6% during this dry year stressing its sensitivity to winter and spring precipitation. Although shrubs are more resilient to precipitation variability when compared with the herbaceous vegetation, the contribution of the understorey vegetation to ecosystem GPP can
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DEFF Research Database (Denmark)
Svenning, J.-C.; Baktoft, Karen H.; Balslev, Henrik
2009-01-01
In Europe, forests have been strongly influenced by human land-use for millennia. Here, we studied the importance of anthropogenic historical factors as determinants of understorey species distributions in a 967 ha Danish forest complex using 156 randomly placed 100-m2 plots, 15 environmental, 9...... dispersal and a strong literature record as ancient-forest species, were still concentrated in areas that were high forest in 1805. Among the younger forests, there were clear floristic differences between those on reclaimed bogs and those not. Apparently remnant populations of wet-soil plants were still...
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Valladares, Fernando; Gianoli, Ernesto; Saldaña, Alfredo
2011-08-01
While the climbing habit allows vines to reach well-lit canopy areas with a minimum investment in support biomass, many of them have to survive under the dim understorey light during certain stages of their life cycle. But, if the growth/survival trade-off widely reported for trees hold for climbing plants, they cannot maximize both light-interception efficiency and shade avoidance (i.e. escaping from the understorey). The seven most important woody climbers occurring in a Chilean temperate evergreen rainforest were studied with the hypothesis that light-capture efficiency of climbers would be positively associated with their abundance in the understorey. Species abundance in the understorey was quantified from their relative frequency and density in field plots, the light environment was quantified by hemispherical photography, the photosynthetic response to light was measured with portable gas-exchange analyser, and the whole shoot light-interception efficiency and carbon gain was estimated with the 3-D computer model Y-plant. Species differed in specific leaf area, leaf mass fraction, above ground leaf area ratio, light-interception efficiency and potential carbon gain. Abundance of species in the understorey was related to whole shoot features but not to leaf level features such as specific leaf area. Potential carbon gain was inversely related to light-interception efficiency. Mutual shading among leaves within a shoot was very low (<20 %). The abundance of climbing plants in this southern rainforest understorey was directly related to their capacity to intercept light efficiently but not to their potential carbon gain. The most abundant climbers in this ecosystem match well with a shade-tolerance syndrome in contrast to the pioneer-like nature of climbers observed in tropical studies. The climbers studied seem to sacrifice high-light searching for coping with the dim understorey light.
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Transfer equations for cesium-137 for coniferous forest understorey plant species
International Nuclear Information System (INIS)
Wirth, E.; Hiersche, L.; Kammerer, L.; Krajewska, G.; Krestel, R.; Mahler, S.; Roemmelt, R.
1994-01-01
The transfer of cesium-137 from organic soil horizons to understorey vegetation has been studied on two coniferous tree sites. In total, 14 different plants preferably taking up their nutrients from organic soil layers were taken into account. A relatively good correlation was found to exist between the transfer factor (Bq/kg plant dry wt./Bq/kg O-horizons dry wt.) for dicotyledons (r=0.51) and berry plants (r=0.63), but there was no correlation for monocotyledons (r= 0 .15). The correlations could not be improved by additionally taking potassium in plant and soil into account. These results are discussed in respect to different parameters influencing the amount of cesium-137 uptake, including plants supported by mycorrhizal fungi
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Soliveres, Santiago; Eldridge, David J
2014-04-01
Shrub canopies in semi-arid environments often produce positive effects on soil fertility, and on the richness and biomass of understorey plant communities. However, both positive and negative effects of shrub encroachment on plant and soil attributes have been reported at the landscape-level. The contrasting results between patch- and landscape-level effects in shrublands could be caused by differences in the degree of shrub encroachment or grazing pressure, both of which are likely to reduce the ability of individual shrubs to ameliorate their understorey environment.We examined how grazing and shrub encroachment (measured as landscape-level shrub cover) influence patch-level effects of shrubs on plant density, biomass and similarity in species composition between shrub understories and open areas, and on soil stability, nutrient cycling, and infiltration in two semi-arid Australian woodlands.Individual shrubs had consistently positive effects on all plant and soil variables (average increase of 23% for all variables). These positive patch-level effects persisted with increasing shrub cover up to our maximum of 50% cover. Heavy grazing negatively affected most of the variables studied (average decline of 11%). It also altered, for some variables, how individual shrubs affected their sub-canopy environment with increasing shrub cover. Thus for species density, biomass and soil infiltration, the positive effect of individual shrubs with increasing shrub cover diminished under heavy grazing. Our study refines predictions of the effects of woody encroachment on ecosystem structure and functioning by showing that heavy grazing, rather than differences in shrub cover, explains the contrasting effects on ecosystem structure and function between individual shrubs and those in dense aggregations. We also discuss how species-specific traits of the encroaching species, such as their height or its ability to fix N, might influence the relationship between their patch
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Cheng, Dongliang; Zhong, Quanlin; Niklas, Karl J; Ma, Yuzhu; Yang, Yusheng; Zhang, Jianhua
2015-02-01
Empirical studies and allometric partitioning (AP) theory indicate that plant above-ground biomass (MA) scales, on average, one-to-one (isometrically) with below-ground biomass (MR) at the level of individual trees and at the level of entire forest communities. However, the ability of the AP theory to predict the biomass allocation patterns of understorey plants has not been established because most previous empirical tests have focused on canopy tree species or very large shrubs. In order to test the AP theory further, 1586 understorey sub-tropical forest plants from 30 sites in south-east China were harvested and examined. The numerical values of the scaling exponents and normalization constants (i.e. slopes and y-intercepts, respectively) of log-log linear MA vs. MR relationships were determined for all individual plants, for each site, across the entire data set, and for data sorted into a total of 19 sub-sets of forest types and successional stages. Similar comparisons of MA/MR were also made. The data revealed that the mean MA/MR of understorey plants was 2·44 and 1·57 across all 1586 plants and for all communities, respectively, and MA scaled nearly isometrically with respect to MR, with scaling exponents of 1·01 for all individual plants and 0·99 for all communities. The scaling exponents did not differ significantly among different forest types or successional stages, but the normalization constants did, and were positively correlated with MA/MR and negatively correlated with scaling exponents across all 1586 plants. The results support the AP theory's prediction that MA scales nearly one-to-one with MR (i.e. MA ∝ MR (≈1·0)) and that plant biomass partitioning for individual plants and at the community level share a strikingly similar pattern, at least for the understorey plants examined in this study. Furthermore, variation in environmental conditions appears to affect the numerical values of normalization constants, but not the scaling exponents
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Cynthia D. Huebner; Kurt W. Gottschalk; Gary W. Miller; Patrick H. Brose
2010-01-01
Research on herbaceous vegetation restoration in forests characterised by overstorey tree harvests, excessive deer herbivory, and a dominant fern understorey is lacking. Most of the plant diversity found in Eastern hardwood forests in the United States is found in the herbaceous understorey layer. Loss of forest herbaceous species is an indicator of declining forest...
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Soliveres, Santiago; Eldridge, David J.; Maestre, Fernando T.; Bowker, Matthew A.; Tighe, Matthew; Escudero, Adrián
2015-01-01
Studies of facilitative interactions as drivers of plant richness along environmental gradients often assume the existence of an overarching stress gradient equally affecting the performance of all the species in a given community. However, co-existing species differ in their ecophysiological adaptations, and do not experience the same stress level under particular environmental conditions. Moreover, these studies assume a unimodal richness-biomass curve, which is not as general as previously thought. We ignored these assumptions to assess changes in plant-plant interactions, and their effect on local species richness, across environmental gradients in semi-arid areas of Spain and Australia. We aimed to understand the relative importance of direct (microhabitat amelioration) and indirect (changes in the competitive relationships among the understorey species: niche segregation, competitive exclusion or intransitivity) mechanisms that might underlie the effects of nurse plants on local species richness. By jointly studying these direct and indirect mechanisms using a unifying framework, we were able to see how our nurse plants (trees, shrubs and tussock grasses) not only increased local richness by expanding the niche of neighbouring species, but also by increasing niche segregation among them, though the latter was not important in all cases. The outcome of the competition-facilitation continuum changed depending on the study area, likely because the different types of stress gradient considered. When driven by both rainfall and temperature, or rainfall alone, the community-wide importance of nurse plants remained constant (Spanish sites), or showed a unimodal relationship along the gradient (Australian sites). This study expands our understanding of the relative roles of plant-plant interactions and environmental conditions as drivers of local species richness in semi-arid environments. These results can also be used to refine predictions about the response of
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Soliveres, Santiago; Eldridge, David J; Maestre, Fernando T; Bowker, Matthew A; Tighe, Matthew; Escudero, Adrián
2011-11-20
Studies of facilitative interactions as drivers of plant richness along environmental gradients often assume the existence of an overarching stress gradient equally affecting the performance of all the species in a given community. However, co-existing species differ in their ecophysiological adaptations, and do not experience the same stress level under particular environmental conditions. Moreover, these studies assume a unimodal richness-biomass curve, which is not as general as previously thought. We ignored these assumptions to assess changes in plant-plant interactions, and their effect on local species richness, across environmental gradients in semi-arid areas of Spain and Australia. We aimed to understand the relative importance of direct (microhabitat amelioration) and indirect (changes in the competitive relationships among the understorey species: niche segregation, competitive exclusion or intransitivity) mechanisms that might underlie the effects of nurse plants on local species richness. By jointly studying these direct and indirect mechanisms using a unifying framework, we were able to see how our nurse plants (trees, shrubs and tussock grasses) not only increased local richness by expanding the niche of neighbouring species, but also by increasing niche segregation among them, though the latter was not important in all cases. The outcome of the competition-facilitation continuum changed depending on the study area, likely because the different types of stress gradient considered. When driven by both rainfall and temperature, or rainfall alone, the community-wide importance of nurse plants remained constant (Spanish sites), or showed a unimodal relationship along the gradient (Australian sites). This study expands our understanding of the relative roles of plant-plant interactions and environmental conditions as drivers of local species richness in semi-arid environments. These results can also be used to refine predictions about the response of
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Balch, Jennifer K.; Massad, Tara J.; Brando, Paulo M.; Nepstad, Daniel C.; Curran, Lisa M.
2013-01-01
Anthropogenic understorey fires affect large areas of tropical forest, yet their effects on woody plant regeneration post-fire remain poorly understood. We examined the effects of repeated experimental fires on woody stem (less than 1 cm at base) mortality, recruitment, species diversity, community similarity and regeneration mode (seed versus sprout) in Mato Grosso, Brazil. From 2004 to 2010, forest plots (50 ha) were burned twice (B2) or five times (B5), and compared with an unburned control (B0). Stem density recovered within a year after the first burn (initial density: 12.4–13.2 stems m−2), but after 6 years, increased mortality and decreased regeneration—primarily of seedlings—led to a 63 per cent and 85 per cent reduction in stem density in B2 and B5, respectively. Seedlings and sprouts across plots in 2010 displayed remarkable community similarity owing to shared abundant species. Although the dominant surviving species were similar across plots, a major increase in sprouting occurred—almost three- and fourfold greater in B2 and B5 than in B0. In B5, 29 species disappeared and were replaced by 11 new species often present along fragmented forest edges. By 2010, the annual burn regime created substantial divergence between the seedling community and the initial adult tree community (greater than or equal to 20 cm dbh). Increased droughts and continued anthropogenic ignitions associated with frontier land uses may promote high-frequency fire regimes that may substantially alter regeneration and therefore successional processes. PMID:23610167
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Dobben, van H.F.; Vries, de W.
2017-01-01
We evaluated effects of atmospheric deposition of nitrogen on the composition of forest understorey vegetation both in space and time, using repeated data from the European wide monitoring program ICP-Forests, which focuses on normally managed forest. Our aim was to assess whether both spatial and
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Collins, Luke; Bradstock, Ross A; Resco de Dios, Victor; Duursma, Remko A; Velasco, Sabrina; Boer, Matthias M
2018-06-01
Rising atmospheric [CO 2 ] and associated climate change are expected to modify primary productivity across a range of ecosystems globally. Increasing aridity is predicted to reduce grassland productivity, although rising [CO 2 ] and associated increases in plant water use efficiency may partially offset the effect of drying on growth. Difficulties arise in predicting the direction and magnitude of future changes in ecosystem productivity, due to limited field experimentation investigating climate and CO 2 interactions. We use repeat near-surface digital photography to quantify the effects of water availability and experimentally manipulated elevated [CO 2 ] (eCO 2 ) on understorey live foliage cover and biomass over three growing seasons in a temperate grassy woodland in south-eastern Australia. We hypothesised that (i) understorey herbaceous productivity is dependent upon soil water availability, and (ii) that eCO 2 will increase productivity, with greatest stimulation occurring under conditions of low water availability. Soil volumetric water content (VWC) determined foliage cover and growth rates over the length of the growing season (August to March), with low VWC (productivity. However, eCO 2 did not increase herbaceous cover and biomass over the duration of the experiment, or mitigate the effects of low water availability on understorey growth rates and cover. Our findings suggest that projected increases in aridity in temperate woodlands are likely to lead to reduced understorey productivity, with little scope for eCO 2 to offset these changes. © 2018 John Wiley & Sons Ltd.
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Directory of Open Access Journals (Sweden)
Franz H. Andrae
2010-08-01
Full Text Available In the central part of Rio Grande do Sul State understoreys of 12 stands of Pinus sp. and one of Araucaria angustifolia O.Ktze were studied, all growing on soils, degraded by agriculture. One pine stand, 10 years old, originated from a natural renovation, the others had been planted 25 to 30 years ago, Araucaria was seeded directly. A total of 575 plots were sampled, 25 m² each, distributed systematically within the stands. Measurements included pines overstorey, and all understorey woody species, separeted into layers of more than 1,3 m high and 1,3 to 0,3 m; the layer lower than 0,3 m included only natural renovation of pines. Understoreys were composed by 121 species, ocurring common and high value timber species, ornamental trees, native and exotic fruit tree species. A higher number of species was present with a very few individuals only. The presence of non woody species like grasses, herbs, ferns and lians also was quantified. The number of tree species and the presence of non woody species did not correlat with density of overstorey pines. Abundance and frequency of species showed no significant diferences, when samples were grouped according to their location in the center or close to stands edge. Distribution pattern of understorey trees within stands was quantified, using Cox’ index, species diversity was compared by means of Shannon-index. Similarity of stands was compared by Sörensen-Index. It was concluded, that exotic species planted on poor agricultural soil may not only be of farmers interest because of their high potential for wood production. These plantations also may be considered from conservationist point of view, since they show an unexpected high diversity, so contributing in a longer run to landscape improvement, possibly due to the small extension of stands.
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Understorey fire frequency and the fate of burned forests in southern Amazonia.
Morton, D C; Le Page, Y; DeFries, R; Collatz, G J; Hurtt, G C
2013-06-05
Recent drought events underscore the vulnerability of Amazon forests to understorey fires. The long-term impact of fires on biodiversity and forest carbon stocks depends on the frequency of fire damages and deforestation rates of burned forests. Here, we characterized the spatial and temporal dynamics of understorey fires (1999-2010) and deforestation (2001-2010) in southern Amazonia using new satellite-based estimates of annual fire activity (greater than 50 ha) and deforestation (greater than 10 ha). Understorey forest fires burned more than 85 500 km(2) between 1999 and 2010 (2.8% of all forests). Forests that burned more than once accounted for 16 per cent of all understorey fires. Repeated fire activity was concentrated in Mato Grosso and eastern Pará, whereas single fires were widespread across the arc of deforestation. Routine fire activity in Mato Grosso coincided with annual periods of low night-time relative humidity, suggesting a strong climate control on both single and repeated fires. Understorey fires occurred in regions with active deforestation, yet the interannual variability of fire and deforestation were uncorrelated, and only 2.6 per cent of forests that burned between 1999 and 2008 were deforested for agricultural use by 2010. Evidence from the past decade suggests that future projections of frontier landscapes in Amazonia should separately consider economic drivers to project future deforestation and climate to project fire risk.
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Energy Technology Data Exchange (ETDEWEB)
Reverchon, Frederique; Xu, Zhihong; Blumfield, Timothy J.; Chen, Chengrong; Abdullah, Kadum M. [Griffith Univ., Nathan, QLD (Australia). Environmental Futures Centre and School of Biomolecular and Physical Sciences
2012-02-15
The objective of this review was to provide a better understanding of how global climate change and fire influence the occurrence of understorey legumes and thereby biological nitrogen (N) fixation rates in forest ecosystems. Legumes are interesting models since they represent an interface between the soil, plant, and microbial compartments, and are directly linked to nutrient cycles through their ability to fix N. As such, they are likely to be affected by environmental changes. Biological N fixation has been shown to increase under enriched CO{sub 2} conditions, but is constrained by the availability of phosphorus and water. Climate change can also influence the species composition of legumes and their symbionts through warming, altered rainfall patterns, or changes in soil physicochemistry, which could modify the effectiveness of the symbiosis. Additionally, global climate change may increase the occurrence and intensity of forest wildfires thereby further influencing the distribution of legumes. The establishment of leguminous species is generally favored by fire, as is N{sub 2} fixation. This fixed N could therefore replenish the N lost through volatilization during the fire. However, fire may also generate shifts in the associated microbial community which could affect the outcome of the symbiosis. Understorey legumes are important functional species, and even when they cannot reasonably be expected to reestablish the nutrient balance in forest soils, they may be used as indicators to monitor nutrient fluxes and the response of forest ecosystems to changing environmental conditions. This would be helpful to accurately model ecosystem N budgets, and since N is often a limiting factor to plant growth and a major constraint on C storage in ecosystems, would allow us to assess more precisely the potential of these forests for C sequestration. (orig.)
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Rebecca L. MacDonald; Han Y.H. Chen; Samuel F. Bartels; Brian J. Palik; Ellie E. Prepas; Frank Gilliam
2015-01-01
Questions: Understanding factors that contribute to the stability of an ecosystem following harvesting is central to predicting responses of boreal ecosystems to increasing human disturbances.While the response of understorey vegetation to harvesting is well understood for upland sites, little is known about compositional stability of riparian understorey vegetation....
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Vild, Ondřej; Roleček, Jan; Hédl, Radim; Kopecký, Martin; Utinek, Dušan
2013-12-15
A substantial part of European lowland woodlands was managed as coppices or wood pastures for millennia. However, traditional management forms were almost completely abandoned in Central Europe by the middle of the 20th century. Combined with the effects of nitrogen deposition and herbivore pressure, shifts in management resulted in biodiversity loss affecting particularly light-demanding oligotrophic plant species. Experimental thinning was applied in a former oak coppice-with-standards in an attempt to restore vanishing understorey plant communities. Two levels of thinning intensity and zero management as control were used on 90 plots. Ten years after the treatment, significant changes in species composition and diversity were observed in heavily thinned plots, while moderate thinning had mostly insignificant effects. Light-demanding oligotrophic species significantly increased, indicating positive consequences of restoration. However, heavy thinning also brought about the expansion of native ruderal species. Alien species remained unchanged. We conclude that the restoration of coppice-with-standards can be an efficient tool to support vanishing light-demanding woodland species. Combined with biodiversity benefits, the increasing demand for biofuel may contribute to the renaissance of traditional management forms in forestry.
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Newbery, D M; Kennedy, D N; Petol, G H; Madani, L; Ridsdale, C E
1999-11-29
Changes in species composition in two 4-ha plots of lowland dipterocarp rainforest at Danum, Sabah, were measured over ten years (1986-1996) for trees > or = 10 cm girth at breast height (gbh). Each included a lower-slope to ridge gradient. The period lay between two drought events of moderate intensity but the forest showed no large lasting responses, suggesting that its species were well adapted to this regime. Mortality and recruitment rates were not unusual in global or regional comparisons. The forest continued to aggrade from its relatively (for Sabah) low basal area in 1986 and, together with the very open upper canopy structure and an abundance of lianas, this suggests a forest in a late stage of recovery from a major disturbance, yet one continually affected by smaller recent setbacks. Mortality and recruitment rates were not related to population size in 1986, but across subplots recruitment was positively correlated with the density and basal area of small trees (10-change in mortality with increasing gbh: in the former it increased, in the latter it decreased. Forest processes are centred on this understorey quasi-stratum. The two replicate plots showed a high correspondence in the mortality, recruitment, population changes and growth rates of small trees for the 49 most abundant species in common to both. Overstorey species had higher rgrs than understorey ones, but both showed considerable ranges in mortality and recruitment rates. The supposed trade-off in traits, viz slower rgr, shade tolerance and lower population turnover in the understorey group versus faster potential growth rate, high light responsiveness and high turnover in the overstorey group, was only partly met, as some understorey species were also very dynamic. The forest at Danum, under such a disturbance-recovery regime, can be viewed as having a dynamic equilibrium in functional and structural terms. A second trade-off in shade-tolerance versus drought-tolerance is suggested for
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Seasonal variation in diversity and abundance of understorey birds ...
African Journals Online (AJOL)
Our findings suggest that in a situation where there is no natural forest, an exotic plantation with suitable indigenous understorey cover can help in protection of birds, including endemic and near-endemic species. Keywords: birds, conservation, Eastern Arc Mountains, plantation, seasonal altitudinal migration, seasons, ...
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Understorey bird abundance and diversity before and after a forest ...
African Journals Online (AJOL)
The understorey bird species diversity before the forest was burned was substantially higher than ..... Conservation interventions are necessary and measures against forest fires are ... I would like to thank the Ministry of Natural Resources and Tourism, Tanzania for permission ... package for education and data analysis.
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Energy Technology Data Exchange (ETDEWEB)
Wang, J.R.; Letchford, T. [Ministry of Forests, Prince George, BC (Canada). Red Rock Research Station; Comeau, P.G. [BC Ministry of Forests, Victoria, BC (Canada); Coopersmith, D. [BC Ministry of Forests, Prince George, BC (Canada)
2000-07-01
Foliar responses of subalpine fir (Abies lasiocarpa (Hook.) Nutt.) to thinning were studied in a 35-yr-old mixed stand of paper birch (Betula papyrifera Marsh.) and conifers. The stand regenerated naturally after a wildfire with a canopy dominated by paper birch (average height 9.8 m) and an understorey dominated by subalpine fir (average height 1.6 m). The stand was thinned to four densities of birch: 0, 600 and 1200 stems ha{sup -1} and control (Unthinned at 2300-6400 stems ha{sup -1}) in the autumn of 1995. The understorey conifers, mainly subalpine fir, were thinned to 1200 stems ha{sup -1}. The study used a completely randomized split-plot design. Three sample trees were systematically selected from each treatment replicate and each tree stratum (upper, intermediate and lower understorey). One-year-old and older age class needles were collected from one south-facing branch within the fifth whorl from the tree top. Thinning of paper birch significantly (p<0.001) increased leaf area and dry weight per 100 needles for intermediate and short trees except in the 0 birch treatment. Understorey subalpine fir trees in 600 stems ha{sup -1} birch (T3) had the largest leaf area and leaf dry weight per 100 1-yr-old needles. Specific leaf area (SLA) decreased from unthinned (T1) to 0 birch (T4). Lower understorey trees had the largest SLA. One-year-old needles had significantly higher N, P and K concentrations in all the thinning treatments. These responses are consistent with the shade tolerance of subalpine fir. The results suggest that when managing a paper birch-conifers mixed wood forest it may be of benefit to understorey conifers to leave a birch canopy as a nursing crop.
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Directory of Open Access Journals (Sweden)
MA. Manhães
Full Text Available Spatial distribution and spatial relationships in capture rates of understorey insectivorous birds and density of arthropods were investigated in a patch of upper montane rain forest in Minas Gerais state, southeastern Brazil, from January to December 2004. The composition of the arthropod fauna collected was similar to that reported for other tropical forests, with predominance of Araneae, Coleoptera, Hymenoptera and Hemiptera non-Heteroptera. A total of 26 bird species were captured, among which the more common were Dysithamnus mentalis, Conopophaga lineata, Platyrinchus mystaceus, Basileuterus culicivorus and Sclerurus scansor. Variation in the bird capture rates among sampling net lines were not correlated with arthropod density. Rather, individual analyses of some bird species suggest that spatial distribution of understorey insectivorous birds is better explained by habitat type.
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Germination of native understorey species for revegetation of New South Wales coal mines
Energy Technology Data Exchange (ETDEWEB)
Gillespie, M.J.; Bellairs, S.M.; Mulligan, D.R. [University of Queensland, St. Lucia, Qld. (Australia). Dept. of Agriculture and Centre for Mined Land Rehabilitation
1997-06-01
This project investigates the suitability of a range of native understorey species for rehabilitation at several coal mines in New South Wales. The germination of seeds from 69 species representing 12 families was tested under controlled laboratory conditions. Germination occurred in all but two of the species tested and 50% germination was exceeded by 29 species. Species of the Mimosaceae, Fabaceae and Proteaceae tended to have above average germination; however species representing other families had variable germination results. A pre-germination heat treatment applied to all of the Acacia species increased germination in some but not all species. Seeds of these understorey species which were used in this trial, are native to the New South Wales coal fields and available commercially or are relatively easy to collect. Glasshouse and field trials are now being undertaken to assess establishment and growth on mine soil, spoil and coal reject materials. 9 refs., 5 figs.
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DEFF Research Database (Denmark)
Borchsenius, Finn; Lozada, Tannya; Knudsen, Jette T.
2016-01-01
The evolution of a mechanism for attaining reproductive isolation between two diverging populations is a key step in the speciation process. We studied phenotypic variation, genetic differentiation, spatial distribution and reproductive ecology in two sympatric forms of the understorey palm Geonoma...
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Directory of Open Access Journals (Sweden)
Henry C. Kahi
2009-03-01
Full Text Available The canopy effects of an exotic and indigenous tree species on soil properties and understorey herbaceous plant species were investigated on the Njemps Flats, Baringo district, Kenya. Samples of soil and herbaceous plant species were obtained within the canopies of systematically selected P. juliflora (exotic and A. tortilis (indigenous trees, and from adjacent open areas. Standing biomass, frequency and cover of understorey plant species were significantly (P
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Improved understorey bamboo cover mapping using a novel hybrid neural network and expert system
Wang, T.; Skidmore, A.K.; Toxopeus, A.G.
2009-01-01
The giant panda is an obligate bamboo grazer. Therefore, the availability and abundance of understorey bamboo determines the quantity and quality of panda habitat. However, there is little or no information about the spatial distribution or abundance of bamboo underneath the forest canopy, due to
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Understorey fire propagation and tree mortality on adjacent areas to an Amazonian deforestation fire
J.A. Carvalho; C.A. Gurgel Veras; E.C. Alvarado; D.V. Sandberg; S.J. Leite; R. Gielow; E.R.C. Rabelo; J.C. Santos
2010-01-01
Fire characteristics in tropical ecosystems are poorly documented quantitatively in the literature. This paper describes an understorey fire propagating across the edges of a biomass burn of a cleared primary forest. The experiment was carried out in 2001 in the Amazon forest near Alta Floresta, state of Mato Grosso, Brazil, as part of biomass burning experiments...
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Avian distribution in treefall gaps and understorey of terra firme forest in the lowland Amazon
JR WUNDERLE; MICHAEL R. WILLIG; LUIZA MAGALLI PINTO HENRIQUES
2005-01-01
We compared the bird distributions in the understorey of treefall gaps and sites with intact canopy in Amazonian terra firme forest in Brazil. We compiled 2216 mist-net captures (116 species) in 32 gap and 32 forest sites over 22.3 months. Gap habitats differed from forest habitats in having higher capture rates, total captures, species richness and diversity....
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Melo, Geruza L; Miotto, Barbara; Peres, Brisa; Cáceres, Nilton C
2013-01-01
Each animal species selects specific microhabitats for protection, foraging, or micro-climate. To understand the distribution patterns of small mammals on the ground and in the understorey, we investigated the use of microhabitats by small mammals in a deciduous forest of southern Brazil. Ten trap stations with seven capture points were used to sample the following microhabitats: liana, fallen log, ground litter, terrestrial ferns, simple-trunk tree, forked tree, and Piper sp. shrubs. Seven field phases were conducted, each for eight consecutive days, from September 2006 through January 2008. Four species of rodents (Akodon montensis, Sooretamys angouya, Oligoryzomys nigripes and Mus musculus) and two species of marsupials (Didelphis albiventris and Gracilinanus microtarsus) were captured. Captured species presented significant differences on their microhabitat use (ANOVA, p = 0.003), particularly between ground and understorey sites. Akodon montensis selected positively terrestrial ferns and trunks, S. angouya selected lianas, D. albiventris selected fallen trunks and Piper sp., and G. microtarsus choose tree trunks and lianas. We demonstrated that the local small-mammal assemblage does select microhabitats, with different types of associations between species and habitats. Besides, there is a strong evidence of habitat selection in order to diminish predation.
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International Nuclear Information System (INIS)
Ewald, Joerg
2000-01-01
Compositional and edaphic gradients were studied in montane forests of the Bavarian Alps (Germany), in which natural mixed deciduous-coniferous tree layers have been altered by past management in favour of Picea abies. Data on species composition and ecological factors were collected in a stratified random sample of 84 quadrats comprising a gradient from pure Picea to pure Fagus sylvatica stands. Data about the understorey composition were subjected to indirect (DCA) and direct gradient analysis (RDA) with the proportion of Picea in the canopy as a constraining variable. Three principal components of a matrix containing seven descriptors of mineral soil, relief and tree layer cover were included as covariables describing the variability of primary ecological factors. Gradients of organic topsoil morphology and chemistry were extracted correspondingly. Responses of individual species, species group and topsoil attributes were studied by simple and partial correlation analysis. Mosses were significantly more abundant and diverse under Picea stands. Few graminoid and herb species were partially associated with Picea, and total understorey richness and cover did not differ systematically by stand type. No relationship between tree layer and understorey diversity was detected at the studied scale. Juvenile Fagus sylvatica was the only woody species significantly less abundant under Picea. In the topsoil lower base saturation, lower pH and larger C/N ratios in the litter layer were partially attributable to the proportion of Picea, only for base saturation a relationship was detected in greater soil depth also. The frequency of broad humus form types did not differ by tree species, nor was overall depth of organic forest floor attributable to canopy composition
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International Nuclear Information System (INIS)
Specht, R. L.; Tyler, M.J.
2010-01-01
Aerodynamic fluxes (frictional, thermal, evaporative) in the atmosphere as it flows over and through a plant community determine the Foliage Projective Covers and eco-morphological attributes of new leaves developed annually in overstorey and understorey strata. The number of leaves produced on vertical foliage shoots depends on available soil water and nutrients, also ambient temperature, during this short growth season. Stem density (number of stems per hectare) and species richness (number of species per hectare) in the overstorey of major Floristic Groups are correlated with annual shoot growth (ASG, t ha-1) in that stratum. Species richness in the overstorey increases in the climatic gradient from the arid to the humid zone as well as with increasing air temperatures (about 10 degree C) from temperate to tropical Australia. Species richness in the understorey is highest in plant communities in temperate Australia, decreasing in the temperature gradient towards the tropics. As with other major plant and animal groups within an ecosystem, the species richness of Amphibia is correlated with the amount of solar energy fixed (per annum) by the major plant formation in the regional photosynthetic potential determined by the foliage shoots (ASG, t ha-1) produced annually in the overstorey.
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Directory of Open Access Journals (Sweden)
R. L. Specht
2010-01-01
Full Text Available Aerodynamic fluxes (frictional, thermal, evaporative in the atmosphere as it flows over and through a plant community determine the Foliage Projective Covers and eco-morphological attributes of new leaves developed annually in overstorey and understorey strata. The number of leaves produced on vertical foliage shoots depends on available soil water and nutrients, also ambient temperature, during this short growth season. Stem density (number of stems per hectare and species richness (number of species per hectare in the overstorey of major Floristic Groups are correlated with annual shoot growth (ASG, t ha−1 in that stratum. Species richness in the overstorey increases in the climatic gradient from the arid to the humid zone as well as with increasing air temperatures (about 10oC from temperate to tropical Australia. Species richness in the understorey is highest in plant communities in temperate Australia, decreasing in the temperature gradient towards the tropics. As with other major plant and animal groups within an ecosystem, the species richness of Amphibia is correlated with the amount of solar energy fixed (per annum by the major plant formation in the region—a photosynthetic potential determined by the foliage shoots (ASG, t ha−1 produced annually in the overstorey.
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Wanthongchai, Dr.; Bauhus, Prof.; Goldammer, Prof.
2009-04-01
Anthropogenic burning in dry dipterocarp forests (DDF) has become a common phenomenon throughout Thailand. It is feared that too frequent fires may affect vegetation structure and composition and thus impact on ecosystem productivity. The aim of this study was to quantify the effects of prescribed fires on sites with different past burning regimes on vegetation structure and composition in the Huay Kha Khaeng Wildlife Sanctuary (HKK), Thailand. Fire frequency was determined from satellite images and ranged from frequent, infrequent, rare and unburned with fire occurrences of 7, 2, 1 and 0 out of the past 10 years, respectively. The pre-burn fuel loads, the overstorey and understorey vegetation structure and composition were determined to investigate the effects of the contrasting past burning regimes. The burning experiment was carried out, applying a three-strip head-fire burning technique. The vegetation structure and composition were sampled again one year after the fire to assess the fire impacts. Aboveground fine fuel loads increased with the length of fire-free interval. The woody plant structures of the frequently burned stand differed from those of the other less frequently burned stands. The species composition of the overstorey on the frequently burned site, in particular that of small sized trees (4.5-10 cm dbh), also differed significantly from that of the other sites. Whilst the ground vegetation including shrubs and herbs did not differ between the past burning regimes, frequent burning obviously promoted the proliferation of graminoid vegetation. There was no clear evidence showing that the prescribed fires affected the mortality of trees (dbh> 4.5 cm) on the sites of the different past burning regimes. The effects of prescribed burning on the understorey vegetation structures varied between the past burning regimes and the understorey vegetation type. Therefore, it is recommended that the DDF at HKK should be subjected to a prescribed fire frequency
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Ma, Ling; Rao, Xingquan; Lu, Ping; Bai, Shahla Hosseini; Xu, Zhihong; Chen, Xiaoyang; Blumfield, Timothy; Xie, Jun
2015-07-01
Eucalyptus spp. is a dominant tree genus in Australia and most Eucalyptus spp. are canopy dominant species. In Australian natural forests, Eucalyptus spp. commonly are associated with understorey legumes which play a crucial role for ecological restoration owing to their nitrogen (N) fixing ability for replenishing the soil N lost after frequent prescribed burning. This study aimed to explore to what extent physiological responses of these species differ 7 and 12 years after last fire. Two most common understorey Acacia spp., Acacia leiocalyx and A. disparrima, as well as one non-leguminous Eucalyptus resinifera, were studied due to their dominance in the forest. Both A. leiocalyx and A. disparrima showed higher carbon (C) assimilation capacity, maximum photosynthetic capacity, and moderate foliar C/N ratio compared with E. resinifera. A. leiocalyx showed various advantages compared to A. disparrima such as higher photosynthetic capacity, adaptation to wider light range and higher foliar total N (TNmass). A. leiocalyx also relied on N2-fixing ability for longer time compared to A. disparrima. The results suggested that the two Acacia spp. were more beneficial to C and N cycles for the post burning ecosystem than the non-N2-fixing species E. resinifera. A. leiocalyx had greater contribution to complementing soil N cycle long after burning compared to A. disparrima.
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Oberle, B.; Grace, J.B.; Chase, J.M.
2009-01-01
Aim: Species richness has been observed to increase with productivity at large spatial scales, though the strength of this relationship varies among functional groups. In forests, canopy trees shade understorey plants, and for this reason we hypothesize that species richness of canopy trees will depend on macroclimate, while species richness of shorter growth forms will additionally be affected by shading from the canopy. In this study we test for differences in species richness-productivity relationships (SRPRs) among growth forms (canopy trees, shrubs, herbaceous species) in small forest plots. Location: We analysed 231 plots ranging from 34.0?? to 48.3?? N latitude and from 75.0?? to 124.2?? W longitude in the United States. Methods: We analysed data collected by the USDA Forest Inventory and Analysis program for plant species richness partitioned into different growth forms, in small plots. We used actual evapotranspiration as a macroclimatic estimate of regional productivity and calculated the area of light-blocking tissue in the immediate area surrounding plots for an estimate of the intensity of local shading. We estimated and compared SRPRs for different partitions of the species richness dataset using generalized linear models and we incorporated the possible indirect effects of shading using a structural equation model. Results: Canopy tree species richness increased strongly with regional productivity, while local shading primarily explained the variation in herbaceous plant richness. Shrub species richness was related to both regional productivity and local shading. Main conclusions: The relationship between total forest plant species richness and productivity at large scales belies strong effects of local interactions. Counter to the pattern for overall richness, we found that understorey herbaceous plant species richness does not respond to regional productivity gradients, and instead is strongly influenced by canopy density, while shrub species
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Hauri, Claudine; Fabricius, Katharina E; Schaffelke, Britta; Humphrey, Craig
2010-09-13
Disturbed coral reefs are often dominated by dense mat- or canopy-forming assemblages of macroalgae. This study investigated how such dense macroalgal assemblages change the chemical and physical microenvironment for understorey corals, and how the altered environmental conditions affect the physiological performance of corals. Field measurements were conducted on macroalgal-dominated inshore reefs in the Great Barrier Reef in quadrats with macroalgal biomass ranging from 235 to 1029 g DW m(-2) dry weight. Underneath mat-forming assemblages, the mean concentration of dissolved oxygen was reduced by 26% and irradiance by 96% compared with conditions above the mat, while concentrations of dissolved organic carbon and soluble reactive phosphorous increased by 26% and 267%, respectively. The difference was significant but less pronounced under canopy-forming assemblages. Dissolved oxygen declined and dissolved inorganic carbon and alkalinity increased with increasing algal biomass underneath mat-forming but not under canopy-forming assemblages. The responses of corals to conditions similar to those found underneath algal assemblages were investigated in an aquarium experiment. Coral nubbins of the species Acropora millepora showed reduced photosynthetic yields and increased RNA/DNA ratios when exposed to conditions simulating those underneath assemblages (pre-incubating seawater with macroalgae, and shading). The magnitude of these stress responses increased with increasing proportion of pre-incubated algal water. Our study shows that mat-forming and, to a lesser extent, canopy-forming macroalgal assemblages alter the physical and chemical microenvironment sufficiently to directly and detrimentally affect the metabolism of corals, potentially impeding reef recovery from algal to coral-dominated states after disturbance. Macroalgal dominance on coral reefs therefore simultaneously represents a consequence and cause of coral reef degradation.
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Directory of Open Access Journals (Sweden)
Claudine Hauri
2010-09-01
Full Text Available Disturbed coral reefs are often dominated by dense mat- or canopy-forming assemblages of macroalgae. This study investigated how such dense macroalgal assemblages change the chemical and physical microenvironment for understorey corals, and how the altered environmental conditions affect the physiological performance of corals. Field measurements were conducted on macroalgal-dominated inshore reefs in the Great Barrier Reef in quadrats with macroalgal biomass ranging from 235 to 1029 g DW m(-2 dry weight. Underneath mat-forming assemblages, the mean concentration of dissolved oxygen was reduced by 26% and irradiance by 96% compared with conditions above the mat, while concentrations of dissolved organic carbon and soluble reactive phosphorous increased by 26% and 267%, respectively. The difference was significant but less pronounced under canopy-forming assemblages. Dissolved oxygen declined and dissolved inorganic carbon and alkalinity increased with increasing algal biomass underneath mat-forming but not under canopy-forming assemblages. The responses of corals to conditions similar to those found underneath algal assemblages were investigated in an aquarium experiment. Coral nubbins of the species Acropora millepora showed reduced photosynthetic yields and increased RNA/DNA ratios when exposed to conditions simulating those underneath assemblages (pre-incubating seawater with macroalgae, and shading. The magnitude of these stress responses increased with increasing proportion of pre-incubated algal water. Our study shows that mat-forming and, to a lesser extent, canopy-forming macroalgal assemblages alter the physical and chemical microenvironment sufficiently to directly and detrimentally affect the metabolism of corals, potentially impeding reef recovery from algal to coral-dominated states after disturbance. Macroalgal dominance on coral reefs therefore simultaneously represents a consequence and cause of coral reef degradation.
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Observing giant panda habitat and forage abundance from space
Wang, T.
2009-01-01
Giant pandas are obligate bamboo grazers. The bamboos favoured by giant
pandas are typical forest understorey plants. Therefore, the availability and
abundance of understorey bamboo is a key factor in determining the quantity
and quality of giant panda food resources. However, -
Understanding plant-to-plant interactions for soil resources in multilayered Iberian dehesas
Moreno, G.; Rolo, V.; Cubera, E.; López-Díaz, L.
2009-04-01
environment much more than understorey usually can, but tree characteristics often confer them a clear competitive advantage and they can strongly out-compete understorey. The net balance of positive-negative interactions varies with the age of trees: while the balance can favor grasses face to seedlings, the contrary can be expected when tree grows. Similarly, while shrubs could favor seedling recruitment, shrubs could affect negatively tree growth and productivity. These changes should be taken into account for defining dehesa structure and determining management practices in order to optimize the use of physical and chemical resources that are spatially and temporally patchy. From our results, it is described how generally holm-oak trees favor understorey forage production through a direct positive effect of shade and improved soil fertility (facilitation). The rooting system together the slow-growing attitude of many oak species could determine a low competitive potential of oaks with herbaceous layer. Its low competitiveness together with its capacity to thrive in poor soils make oaks genre very suitable for long-term agroforestry systems in Iberian Peninsula. However, although a certain complementary uses of soil resources seems occur for trees and native grasses (very distinct root system profile), the potential benefit of trees has a small actual facilitative effect because the competitive use of soil water by trees overrides its positive effects, especially under semi-arid conditions. As consequence, the net balance of trees on pasture yield is very variably with situations where pasture yield is widely increased in the vicinity of the trees and others where the contrary is found. Tree clearance practiced in dehesas affects positively the development of the understory pasture, but also the single tree functions which take advantage of the low tree density characteristic of dehesas. Tree roots access water through a large volume of soil resources (especially water
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Directory of Open Access Journals (Sweden)
Chandra Shekher Sanwal
2016-01-01
Full Text Available The integration of Andrographis paniculata under Pinus roxburghii (Chir pine plantation has been studied to evaluate the growth and yield for its economic viability and conservation. It was grown on three topographical aspects, namely, northern, north-western, and western, at a spacing of 30 cm × 30 cm, followed by three tillage depths, namely, minimum (0 cm, medium (up to 10 cm, and deep (up to 15 cm tillage. The growth parameters, namely, plant height and number of branches per plant, were recorded as significantly higher on western aspect and lowest on northern aspect except for leaf area index which was found nonsignificant. However under all tillage practices all the growth parameters in both understorey and open conditions were found to be nonsignificant except for plant height which was found to be significantly highest under deep tillage and lowest under minimum tillage. The study of net returns for Andrographis paniculata revealed that it had positive average annual returns even in understorey conditions which indicate its possible economic viability under integration of Chir pine plantations. Hence net returns can be enhanced by integrating Andrographis paniculata and this silvimedicinal system can be suggested which will help utilizing an unutilized part of land and increase total productivity from such lands besides conservation of the A. paniculata in situ.
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Sanwal, Chandra Shekher; Bhardwaj, S. D.
2016-01-01
The integration of Andrographis paniculata under Pinus roxburghii (Chir pine) plantation has been studied to evaluate the growth and yield for its economic viability and conservation. It was grown on three topographical aspects, namely, northern, north-western, and western, at a spacing of 30 cm × 30 cm, followed by three tillage depths, namely, minimum (0 cm), medium (up to 10 cm), and deep (up to 15 cm) tillage. The growth parameters, namely, plant height and number of branches per plant, were recorded as significantly higher on western aspect and lowest on northern aspect except for leaf area index which was found nonsignificant. However under all tillage practices all the growth parameters in both understorey and open conditions were found to be nonsignificant except for plant height which was found to be significantly highest under deep tillage and lowest under minimum tillage. The study of net returns for Andrographis paniculata revealed that it had positive average annual returns even in understorey conditions which indicate its possible economic viability under integration of Chir pine plantations. Hence net returns can be enhanced by integrating Andrographis paniculata and this silvimedicinal system can be suggested which will help utilizing an unutilized part of land and increase total productivity from such lands besides conservation of the A. paniculata in situ. PMID:27563482
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Toxic plants affecting the nervous system of ruminants and horses in Brazil
This review updates information about neurotoxic plants affecting ruminants and equidae in Brazil. Currently in the country, there are at least 131 toxic plants belonging to 79 genera. Thirty one of these poisonous plants affect the nervous system. Swainsonine-containing plants (Ipomoea spp., Turbin...
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J. A. Parrotta; O. H. Knowles; J.M. Wunderle Jr.
1997-01-01
Patterns of plant and animal diversity were studied in a 10-year-old native species reforestation area at a bauxite-mined site at porto Trombetas in western Para State, Brazil. Understorey and overstorey floristic composition and structure, understorey light conditions, forest floor development and soil properties were evaluated in a total of 38 78.5-m2
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Toxic plants affecting the nervous system of ruminants and horses in Brazil
Directory of Open Access Journals (Sweden)
Franklin Riet-Correa
Full Text Available ABSTRACT: This review updates information about neurotoxic plants affecting ruminants and equidae in Brazil. Currently in the country, there are at least 131 toxic plants belonging to 79 genera. Thirty one of these poisonous plants affect the nervous system. Swainsonine-containing plants (Ipomoea spp., Turbina cordata and Sida carpinifolia cause numerous outbreaks of poisoning, mainly in goats, but cattle and horses are occasionally affected. The poisoning by Ipomoea asarifolia, a tremorgenic plant, is very common in sheep, goats and cattle in the Northeastern region and in the Marajo island. Poisoning by the pods of Prosopis juliflora are frequent in cattle in Northeastern Brazil; occasionally this poisoning affects goats and more rarely sheep. Some poisonings by plants, such as Hybanthus calceolaria, Ipomoea marcellia and Talisia esculenta in ruminants and Indigofera lespedezioides in horses were recently described and needs to be accurately investigated about its occurrence and importance. Other plants poisonings causing nervous signs in ruminants and equidae are less important, but should be considered for the differential diagnosis of neurologic diseases.
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Precipitation affects plant communication and defense.
Pezzola, Enrico; Mancuso, Stefano; Karban, Richard
2017-06-01
Anti-herbivore defense shows high levels of both inter- and intraspecific variability. Defending against herbivores may be costly to the plant when it requires a tradeoff in allocation between defense and other missed opportunities, such as reproduction. Indeed, the plastic expression of defensive traits allows the plant to invest resources in defense only when the risk of being damaged actually increases, avoiding wasted resources. Plants may assess risk by responding to volatile cues emitted by neighbors that are under attack. Most plastic responses likely depend on environmental conditions. In this experiment, we investigated the effect of water availability on resistance induced by volatile cues in sagebrush. We found that plants receiving additional water over summer and/or volatile cues from neighbor donor plants showed reduced herbivore damage compared to control plants. Interestingly, we found no evidence of interactions between additional water and volatile cues. We performed an inferential analysis comparing historical records of the levels of herbivore damage during different years that had different temperature and precipitation accumulations. Results confirmed findings from the experiment, as the regression model indicated that sagebrush was better defended during wetter and hotter seasons. Reports from the literature indicated that sagebrush is extremely sensitive to water availability in the soil. We suggest that water availability may directly affect resistance of herbivory as well as sensitivity to cues of damage. Costs and benefits of allocating resources to defensive traits may vary with environmental conditions. © 2017 by the Ecological Society of America.
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Oguchi, Riichi; Hiura, Tsutom; Hikosaka, Kouki
2017-08-01
Gap formation increases the light intensity in the forest understorey. The growth responses of seedlings to the increase in light availability show interspecific variation, which is considered to promote biodiversity in forests. At the leaf level, some species increase their photosynthetic capacity in response to gap formation, whereas others do not. Here we address the question of whether the interspecific difference in the photosynthetic response results in the interspecific variation in the growth response. If so, the interspecific difference in photosynthetic response would also contribute to species coexistence in forests. We also address the further relevant question of why some species do not increase their photosynthetic capacity. We assumed that some cost of photosynthetic plasticity may constrain acquisition of the plasticity in some species, and hypothesized that species with larger photosynthetic plasticity exhibit better growth after gap formation and lower survivorship in the shade understorey of a cool-temperate deciduous forest. We created gaps by felling canopy trees and studied the relationship between the photosynthetic response and the subsequent growth rate of seedlings. Naturally growing seedlings of six deciduous woody species were used and their mortality was examined for 8 years. The light-saturated rate of photosynthesis (Pmax) and the relative growth rate (RGR) of the seedlings of all study species increased at gap plots. The extent of these increases varied among the species. The stimulation of RGR over 4 years after gap formation was strongly correlated with change in photosynthetic capacity of newly expanded leaves. The increase in RGR and Pmax correlated with the 8-year mortality at control plots. These results suggest a trade-off between photosynthetic plasticity and the understorey shade tolerance. Gap-demanding species may acquire photosynthetic plasticity, sacrificing shade tolerances, whereas gap-independent species may acquire
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Strategic rehabilitation of the earthquake affected microhydropower plants in Nepal
Baidar, B.; Koirala, R.; Neopane, H. P.; Shrestha, M. V.; Thapa, B.
2016-11-01
Most people in the rural areas of Nepal rely on Micro-hydro Power Plants (MHPs) for their energy sources. With around four decade experiences in design and development of MHPs, Nepalese techno-entrepreneurs have gained wider reputation in the South Asian region and the beyond. However with the lack of competences in developing Francis turbines, majority of the MHPs are equipped with either Pelton of Cross Flow turbine, even though Francis units are suitable. With the devastating earthquake of a 7.6 magnitude that struck in the Gorkha district on Saturday, 25 April 2015, about 76 km northwest of the capital city Kathmandu, and the aftershocks followed claimed more than 8000 lives. It did not leave hydropower plants either. Many big plants have been affected and hundreds of MHPs were damaged, needing short to long term rehabilitation. The preliminary assessment of the 61 affected MHPs in the 6 earthquake affected districts shows more than 50% sites are suitable for Francis turbine. Hence the strategic rehabilitation plan has been developed in the present paper for the affected plants considering issues like geographical shift, dislocation of people and also with the focus on replacing the old turbine with Francis turbine in the suitable sites. The similar strategy can also be implemented in other developing countries with such situations.
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Hendriks, Marloes; Ravenek, Janneke M; Smit-Tiekstra, Annemiek E; van der Paauw, Jan Willem; de Caluwe, Hannie; van der Putten, Wim H; de Kroon, Hans; Mommer, Liesje
2015-08-01
Plant-soil feedback is receiving increasing interest as a factor influencing plant competition and species coexistence in grasslands. However, we do not know how spatial distribution of plant-soil feedback affects plant below-ground interactions. We investigated the way in which spatial heterogeneity of soil biota affects competitive interactions in grassland plant species. We performed a pairwise competition experiment combined with heterogeneous distribution of soil biota using four grassland plant species and their soil biota. Patches were applied as quadrants of 'own' and 'foreign' soils from all plant species in all pairwise combinations. To evaluate interspecific root responses, species-specific root biomass was quantified using real-time PCR. All plant species suffered negative soil feedback, but strength was species-specific, reflected by a decrease in root growth in own compared with foreign soil. Reduction in root growth in own patches by the superior plant competitor provided opportunities for inferior competitors to increase root biomass in these patches. These patterns did not cascade into above-ground effects during our experiment. We show that root distributions can be determined by spatial heterogeneity of soil biota, affecting plant below-ground competitive interactions. Thus, spatial heterogeneity of soil biota may contribute to plant species coexistence in species-rich grasslands. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.
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Uptake of some radionuclides by woody plants growing in the rainforest of Western Ghats in India
International Nuclear Information System (INIS)
Manigandan, P.K.; Chandar Shekar, B.
2014-01-01
Transfer of the naturally occurring radionuclides 238 U, 232 Th, and 40 K, and the fallout radionuclide 210 Po to different wild plant species in the rainforest of Western Ghats was analyzed. A number of physiologically different plants from the top storey and understorey, such as shrubs and epiphytes, were compared. The concentrations of these radionuclides in the plants and soil were measured using a gamma ray spectrometer and an alpha counter, and were found to vary widely within plants and between species. The soil-plant ratios also varied between species while Elaeocarpus oblongus and epiphytic plants exhibited preferential uptake of these radionuclides. As a result, the dust particles trapped in the root systems of epiphytes could be used as bioindicators of fallout radionuclides in the Western Ghats. - Highlights: • Predominant plants species of the region were selected for analysis. • CR Model was employed to these plants spices. • Two plants were indicated preferential uptake of these radionuclides. • Bioindicator was identified in the Western Ghats Environment
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Assessing soil and plant parameters affecting uranium availability and plant uptake
International Nuclear Information System (INIS)
Vandenhove, H.
2009-01-01
In the assessment of the potential impact of contaminants in soils and the requirement for the implementation of corrective actions, it is important to determine the contaminant's mobility and bioavailability and to identify the processes and parameters ruling it. Mobility and bioavailability of contaminants are among others affected by the physicochemical characteristics of the environment itself and plant properties. This is also the case for uranium (U), reported to be the most frequent radionuclide contaminant in ground and surface water and soils. The actual failure of the available transfer factor (TF) data and their broad relation to soil type to be an appropriate measure for food chain transfer in assessment models, calls for a more mechanistic understanding of the individual processes affecting bioavailability. The objectives of this study were (1) to test if Diffusive Gradient in Thin film (DGT) measured concentrations adequately assess U bioavailability and (2) to evaluate if differences in U uptake by plants can be explained by variation in root-mediated changes in selected soil properties and assess the role of organic acids in this process
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Effects of visitor pressure on understory vegetation in Warsaw forested parks (Poland).
Sikorski, Piotr; Szumacher, Iwona; Sikorska, Daria; Kozak, Marcin; Wierzba, Marek
2013-07-01
Visitor's access to understorey vegetation in park forest stands results in the impoverishment of plant species composition and a reduction in habitat quality. The phenomenon of biotic homogenisation is typical in urban landscapes, but it can proceed differently depending on the scale, a detail that has not been observed in previous studies. This research was carried out in seven Warsaw parks (both public and restricted access). Thirty-four forested areas were randomly selected, some subjected to strong visitors' pressure and some within restricted access areas, free of such impacts. The latter category included woodlands growing in old forest and secondary habitats. Public access to the study areas contributed to the disappearance of some forest species and their replacement by cosmopolitan non-forest species, leading to loss of floristic biodiversity in areas of high ecological importance at the city scale. Some human-induced factors, including soil compaction and changes in soil pH, moisture and capillary volume, were found to cause habitat changes that favoured native non-forest plants. Despite changes in species composition, the taxonomic similarity of understorey vegetation in both categories--public access and restricted access--was comparable. In a distance gradient of measurements taken around selected individual trees, there was found to be significant variation (in light, soil pH and compaction) affecting the quality and quantity of understorey vegetation (including rare species). In conclusion, the protection of rare forest species could be achieved by limiting access to forested areas, particularly in old forest fragments, and we highly recommend its consideration in the proposal of future park restoration plans.
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Sarlikioti, V.; Visser, de P.H.B.; Buck-Sorlin, G.H.; Marcelis, L.F.M.
2011-01-01
Background and Aims - Manipulation of plant structure can strongly affect light distribution in the canopy and photosynthesis. The aim of this paper is to find a plant ideotype for optimization of light absorption and canopy photosynthesis. Using a static functional structural plant model (FSPM), a
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Kubásek, Jiří; Urban, Otmar; Šantrůček, Jiří
2013-12-01
Plants in the field are commonly exposed to fluctuating light intensity, caused by variable cloud cover, self-shading of leaves in the canopy and/or leaf movement due to turbulence. In contrast to C3 plant species, only little is known about the effects of dynamic light (DL) on photosynthesis and growth in C4 plants. Two C4 and two C3 monocot and eudicot species were grown under steady light or DL conditions with equal sum of daily incident photon flux. We measured leaf gas exchange, plant growth and dry matter carbon isotope discrimination to infer CO2 bundle sheath leakiness in C4 plants. The growth of all species was reduced by DL, despite only small changes in steady-state gas exchange characteristics, and this effect was more pronounced in C4 than C3 species due to lower assimilation at light transitions. This was partially attributed to increased bundle sheath leakiness in C4 plants under the simulated lightfleck conditions. We hypothesize that DL leads to imbalances in the coordination of C4 and C3 cycles and increasing leakiness, thereby decreasing the quantum efficiency of photosynthesis. In addition to their other constraints, the inability of C4 plants to efficiently utilize fluctuating light likely contributes to their absence in such environments as forest understoreys. © 2013 Scandinavian Plant Physiology Society.
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Assouline, Shmuel; Or, Dani
2013-01-01
Plant gas exchange is a key process shaping global hydrological and carbon cycles and is often characterized by plant water use efficiency (WUE - the ratio of CO2 gain to water vapor loss). Plant fossil record suggests that plant adaptation to changing atmospheric CO2 involved correlated evolution of stomata density (d) and size (s), and related maximal aperture, amax . We interpreted the fossil record of s and d correlated evolution during the Phanerozoic to quantify impacts on gas conductance affecting plant transpiration, E, and CO2 uptake, A, independently, and consequently, on plant WUE. A shift in stomata configuration from large s-low d to small s-high d in response to decreasing atmospheric CO2 resulted in large changes in plant gas exchange characteristics. The relationships between gas conductance, gws , A and E and maximal relative transpiring leaf area, (amax ⋅d), exhibited hysteretic-like behavior. The new WUE trend derived from independent estimates of A and E differs from established WUE-CO2 trends for atmospheric CO2 concentrations exceeding 1,200 ppm. In contrast with a nearly-linear decrease in WUE with decreasing CO2 obtained by standard methods, the newly estimated WUE trend exhibits remarkably stable values for an extended geologic period during which atmospheric CO2 dropped from 3,500 to 1,200 ppm. Pending additional tests, the findings may affect projected impacts of increased atmospheric CO2 on components of the global hydrological cycle.
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Directory of Open Access Journals (Sweden)
GERUZA L. MELO
2013-06-01
Full Text Available Each animal species selects specific microhabitats for protection, foraging, or micro-climate. To understand the distribution patterns of small mammals on the ground and in the understorey, we investigated the use of microhabitats by small mammals in a deciduous forest of southern Brazil. Ten trap stations with seven capture points were used to sample the following microhabitats: liana, fallen log, ground litter, terrestrial ferns, simple-trunk tree, forked tree, and Piper sp. shrubs. Seven field phases were conducted, each for eight consecutive days, from September 2006 through January 2008. Four species of rodents (Akodon montensis, Sooretamys angouya, Oligoryzomys nigripes and Mus musculus and two species of marsupials (Didelphis albiventris and Gracilinanus microtarsus were captured. Captured species presented significant differences on their microhabitat use (ANOVA, p = 0.003, particularly between ground and understorey sites. Akodon montensis selected positively terrestrial ferns and trunks, S. angouya selected lianas, D. albiventris selected fallen trunks and Piper sp., and G. microtarsus choose tree trunks and lianas. We demonstrated that the local small-mammal assemblage does select microhabitats, with different types of associations between species and habitats. Besides, there is a strong evidence of habitat selection in order to diminish predation.Cada espécie animal pode apresentar seletividade por micro-habitats priorizando proteção, forrageio ou microclima. Para compreender os padrões de distribuição de pequenos mamíferos ao nível do solo e de sub-bosque, nós analisamos o uso de micro-habitat por pequenos mamíferos em uma floresta estacional no sul do Brasil. Dez estações amostrais com sete pontos de captura foram usadas para amostragem dos seguintes microhabitats: liana, tronco caído, solo apenas coberto por folhiço, solo coberto por samambaias, árvore com tronco simples, árvore com bifurcações e arbustos do g
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Plant functional diversity affects climate-vegetation interaction
Groner, Vivienne P.; Raddatz, Thomas; Reick, Christian H.; Claussen, Martin
2018-04-01
We present how variations in plant functional diversity affect climate-vegetation interaction towards the end of the African Humid Period (AHP) in coupled land-atmosphere simulations using the Max Planck Institute Earth system model (MPI-ESM). In experiments with AHP boundary conditions, the extent of the green Sahara varies considerably with changes in plant functional diversity. Differences in vegetation cover extent and plant functional type (PFT) composition translate into significantly different land surface parameters, water cycling, and surface energy budgets. These changes have not only regional consequences but considerably alter large-scale atmospheric circulation patterns and the position of the tropical rain belt. Towards the end of the AHP, simulations with the standard PFT set in MPI-ESM depict a gradual decrease of precipitation and vegetation cover over time, while simulations with modified PFT composition show either a sharp decline of both variables or an even slower retreat. Thus, not the quantitative but the qualitative PFT composition determines climate-vegetation interaction and the climate-vegetation system response to external forcing. The sensitivity of simulated system states to changes in PFT composition raises the question how realistically Earth system models can actually represent climate-vegetation interaction, considering the poor representation of plant diversity in the current generation of land surface models.
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International Nuclear Information System (INIS)
Suomela, M.; Rahola, T.; Bergman, R.; Bunzl, K.; Jaakkola, T.
1999-08-01
The project EPORA 'Effects of Industrial Pollution on Distribution Dynamics of Radionuclides in Boreal Understorey Ecosystems' is a part of the Nuclear Fission Safety Research programme of the European Union. A suitable environment for the study was found in the surroundings of the Cu-Ni smelter in Monchegorsk, in NW Russia where the huge atmospheric emissions from the smelter have polluted the environment since the 1930's. Samples of soil, litter, plants and runoff water were taken. Total concentrations of the main pollutants, Ni and Cu, in the organic soil increased from about 10 mg kg -1 at the reference site in Finland to about 5000 mg kg -1 at the most polluted site in Russia. Similar trends were observed for exchangeable fractions and plant concentrations of the same elements. Concentrations of exchangeable K, Ca, and Mg in the organic soil decreased strongly with increased input of chemical pollutants. The radionuclides studied were 137 Cs, 90 Sr and 239+240 Pu, mainly originating from the atmospheric nuclear weapons tests. The contribution of the Chernobyl derived 137 Cs deposition was about 10% but insignificant for the other nuclides. The activity distribution of all three radionuclides in the soil, their corresponding residence half-times as well as their aggregated trencher factors for various plants depended on the degree of pollution: Activity distribution: in the litter layer, the activity of all three radionuclides increased continually from the reference site to the most polluted site. This effect was most pronounced for 239+240 Pu and least for 90 Sr and could, at least partly, be explained by the increase of the thickness of this layer. In the root zone, the opposite effect was observed: the largest fraction of all radionuclides was found at the reference site. In the organic layer, the exchangeable fractions of 137 Cs, 90 Sr and 239+240 Pu decreased with increasing pollution. Residence half-times: in the root zone, the residence half-times of 90
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Energy Technology Data Exchange (ETDEWEB)
Suomela, M.; Rahola, T. [Radiation and Nuclear Safety Authority, Helsinki (Finland); Bergman, R. [National Defence Research Establishment (Sweden); Bunzl, K. [National Research Center for Environmental and Health (Germany); Jaakkola, T. [Helsinki Univ. (Finland). Radiochemical Lab.; Steinnes, E. [Norwegian University of Science and Technology (Norway)
1999-08-01
The project EPORA 'Effects of Industrial Pollution on Distribution Dynamics of Radionuclides in Boreal Understorey Ecosystems' is a part of the Nuclear Fission Safety Research programme of the European Union. A suitable environment for the study was found in the surroundings of the Cu-Ni smelter in Monchegorsk, in NW Russia where the huge atmospheric emissions from the smelter have polluted the environment since the 1930's. Samples of soil, litter, plants and runoff water were taken. Total concentrations of the mainpollutants, Ni and Cu, in the organic soil increased from about 10 mg kg{sup -1} at the reference site in Finland to about 5000 mg kg{sup -1} at the most polluted site in Russia. Similar trends were observed for exchangeable fractions and plant concentrations of the same elements. Concentrations of exchangeable K, Ca, and Mg in the organic soil decreased strongly with increased input of chemical pollutants. The radionuclides studied were {sup 137}Cs, {sup 90}Sr and {sup 239+240}Pu, mainly originating from the atmospheric nuclear weapons tests. The contribution of the Chernobyl derived {sup 137}Cs deposition was about 10% but insignificant for the other nuclides. The activity distribution of all three radionuclides in the soil, their corresponding residence half-times as well as their aggregated trencher factors for various plants depended on the degree of pollution: Activity distribution: in the litter layer, the activity of all three radionuclides increased continually from the reference site to the most polluted site. This effect was most pronounced for {sup 239+240}Pu and least for {sup 90}Sr and could, at least partly, be explained by the increase of the thickness of this layer. In the root zone, the opposite effect was observed: the largest fraction of all radionuclides was found at the reference site. In the organic layer, the exchangeable fractions of {sup 137}Cs, {sup 90}Sr and {sup 239+240}Pu decreased with increasing pollution
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Comparative Analysis of Woody Plants Biomass on the Affected
African Journals Online (AJOL)
Nwokem et al.
stands that were generated from the field using sample quadrats and measuring ... woody plants on the affected and restricted land management practices. F u ll L en .... divided into 6 strata that served as a guide to locate the quadrat samples.
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Herbivory of an invasive slug is affected by earthworms and the composition of plant communities.
Zaller, Johann G; Parth, Myriam; Szunyogh, Ilona; Semmelrock, Ines; Sochurek, Susanne; Pinheiro, Marcia; Frank, Thomas; Drapela, Thomas
2013-05-13
Biodiversity loss and species invasions are among the most important human-induced global changes. Moreover, these two processes are interlinked as ecosystem invasibility is considered to increase with decreasing biodiversity. In temperate grasslands, earthworms serve as important ecosystem engineers making up the majority of soil faunal biomass. Herbivore behaviour has been shown to be affected by earthworms, however it is unclear whether these effects differ with the composition of plant communities. To test this we conducted a mesocosm experiment where we added earthworms (Annelida: Lumbricidae) to planted grassland communities with different plant species composition (3 vs. 12 plant spp.). Plant communities had equal plant densities and ratios of the functional groups grasses, non-leguminous forbs and legumes. Later, Arion vulgaris slugs (formerly known as A. lusitanicus; Gastropoda: Arionidae) were added and allowed to freely choose among the available plant species. This slug species is listed among the 100 worst alien species in Europe. We hypothesized that (i) the food choice of slugs would be altered by earthworms' specific effects on the growth and nutrient content of plant species, (ii) slug herbivory will be less affected by earthworms in plant communities containing more plant species than in those with fewer plant species because of a more readily utilization of plant resources making the impacts of earthworms less pronounced. Slug herbivory was significantly affected by both earthworms and plant species composition. Slugs damaged 60% less leaves when earthworms were present, regardless of the species composition of the plant communities. Percent leaf area consumed by slugs was 40% lower in communities containing 12 plant species; in communities containing only three species earthworms increased slug leaf area consumption. Grasses were generally avoided by slugs. Leaf length and number of tillers was increased in mesocosms containing more plant
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Ludwig, F.
2001-01-01
Keywords: Rangelands, Semi-arid areas, stable isotopes, Acacia, C 4- grasses, plant nutrients, soil nutrients, soil water, plant water relations
Savanna trees can either increase or decrease the productivity of understorey grasses. Trees reduce grass
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Traits of estuarine marsh plants affect wave dissipation
Schulte Ostermann, Tilla; Heuner, Maike; Bouma, Tjeerd
2017-04-01
Estuarine vegetation can attenuate hydrodynamic forces such as waves or flow velocities and therefore has an important role in natural tidal bank protection. This function depends on the degree of hydrodynamic forces, bank morphology and on plant traits of the dominant species. The traits vary between the species but also between different marsh sites. Biomass, stem density and biomechanical properties are crucial factors that influence the rate of wave dissipation. These properties illustrate the trade-offs a species is facing in such a dynamic habitat and highlight the ability of dominant species such as Bolboschoenus maritimus and Schoenoplectus tabernaemontani to protect the tidal bank. Along the Elbe estuary, traits of dominant marsh plant species were measured on different sites. The sites vary e.g. in their elevation, salt levels and inundation periods. To analyse the role that plant traits can play in wave dissipation, the structure of the vegetation as well as the composition was recorded. Biomechanical tests helped to understand the species traits regarding stem flexibility and to determine the effects of plant traits on wave dynamics and vice versa. On the conference, we will present how plant traits affect the wave dissipation on tidal marshes and why they vary.
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Ghimire, Chandra Prasad; Bruijnzeel, L Adrian; Lubczynski, Maciek W; Zwartendijk, Bob W; Odongo, Vincent Omondi; Ravelona, Maafaka; van Meerveld, H J Ilja
2018-04-21
It has been suggested that vigorous secondary tropical forests can have very high transpiration rates, but sap flow and stomatal conductance dynamics of trees and shrubs in these forests are understudied. In an effort to address this knowledge gap, sap flow (thermal dissipation method, 12 trees) and stomatal conductance (porometry, six trees) were measured for young (5-7 years) Psiadia altissima (DC.) Drake trees, a widely occurring species dominating young regrowth following abandonment of swidden agriculture in upland eastern Madagascar. In addition, stomatal conductance (gs) was determined for three individuals of two locally common invasive shrubs (Lantana camara L. and Rubus moluccanus L.) during three periods with contrasting soil moisture conditions. Values of gs for the three investigated species were significantly higher and more sensitive to climatic conditions during the wet period compared with the dry period. Further, gs of the understorey shrubs was much more sensitive to soil moisture content than that of the trees. Tree transpiration rates (Ec) were relatively stable during the dry season and were only affected somewhat by soil water content at the end of the dry season, suggesting the trees had continued access to soil water despite drying out of the topsoil. The Ec exhibited a plateau-shaped relation with vapour pressure deficit (VPD), which was attributed to stomatal closure at high VPD. Vapour pressure deficit was the major driver of variation in Ec, during both the wet and the dry season. Overall water use of the trees was modest, possibly reflecting low site fertility after three swidden cultivation cycles. The observed contrast in gs response to soil water and climatic conditions for the trees and shrubs underscores the need to take root distributions into account when modelling transpiration from regenerating tropical forests.
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Directory of Open Access Journals (Sweden)
Nicole Wäschke
Full Text Available Plant diversity is known to affect success of host location by pest insects, but its effect on olfactory orientation of non-pest insect species has hardly been addressed. First, we tested in laboratory experiments the hypothesis that non-host plants, which increase odour complexity in habitats, affect the host location ability of herbivores and parasitoids. Furthermore, we recorded field data of plant diversity in addition to herbivore and parasitoid abundance at 77 grassland sites in three different regions in Germany in order to elucidate whether our laboratory results reflect the field situation. As a model system we used the herb Plantago lanceolata, the herbivorous weevil Mecinus pascuorum, and its larval parasitoid Mesopolobus incultus. The laboratory bioassays revealed that both the herbivorous weevil and its larval parasitoid can locate their host plant and host via olfactory cues even in the presence of non-host odour. In a newly established two-circle olfactometer, the weeviĺs capability to detect host plant odour was not affected by odours from non-host plants. However, addition of non-host plant odours to host plant odour enhanced the weeviĺs foraging activity. The parasitoid was attracted by a combination of host plant and host volatiles in both the absence and presence of non-host plant volatiles in a Y-tube olfactometer. In dual choice tests the parasitoid preferred the blend of host plant and host volatiles over its combination with non-host plant volatiles. In the field, no indication was found that high plant diversity disturbs host (plant location by the weevil and its parasitoid. In contrast, plant diversity was positively correlated with weevil abundance, whereas parasitoid abundance was independent of plant diversity. Therefore, we conclude that weevils and parasitoids showed the sensory capacity to successfully cope with complex vegetation odours when searching for hosts.
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Factors affecting the transfer of radionuclides from the environment to plants
International Nuclear Information System (INIS)
Golmakani, S.; Moghaddam, V.M.; Hosseini, T.
2008-01-01
Much of our food directly or indirectly originates from plant material; thus, detailed studies on plant contamination processes are an essential part of international environmental research. This overview attempts to identify and describe the most important parameters and processes affecting the behaviour of radionuclide transfer to plants. Many parameters influence these processes. These parameters are related to: (1) plant, (2) soil, (3) radionuclide, (4) climate and (5) time. Often there is no boundary between the factors and they are linked to each other. Knowledge of important factors in radionuclide transfer to plants can help to assess and prevent radiological exposure of humans. This knowledge can also help to guide researches and modelling related to transfer of radionuclides to food chain. (authors)
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Gamma irradiation on canola seeds affects herbivore-plant and host-parasitoid interactions
International Nuclear Information System (INIS)
Akandeh, M.; Kocheili, F.; Rasekh, A.; Soufbaf, M.
2017-01-01
As an agricultural modernization, gamma irradiation is an important method for enhancing crop yield and quality. Nevertheless, its use can alter other plant traits such as nutrition and resistance to different biotic/abiotic stresses that consequently affect plant-insect interactions. A tritrophic system was utilized based on two canola mutant lines produced through gamma irradiation (RGS 8-1 and Talaye 8-3). Plutella xylostella (L.), as a worldwide pest of Brassicaceae and Cotesia vestalis (Holiday) as a key biocontrol agent of P. xylostella were examined for the potential indirect effects of canola seed irradiation on the experimental insects' performance when acting on the respective mutant lines. This study showed that physical mutation did not affect plant nitrogen and herbivore-damaged total phenolics; however, phenolic compounds showed greater concentration in damaged leaves than undamaged leaves of both mutant and control plants. The relative growth rate and pupal weight of P. xylostella reared on RGS 8-1 were significantly higher than those reared on the control RGS. There was no significant difference by performance parameters of the parasitoid, C. vestalis, including total pre-oviposition period, adult longevity, adult fresh body weight of males and females, pupal weight, forewing area, and total longevity of both sexes on tested canola cultivars in comparison with their mutant lines. Life table parameters of C. vestalis on mutant lines of both cultivars, RGS and Talaye, were not significantly different from their control treatments. Comprehensive studies should be conducted to find out the mechanisms under which gamma rays affect plant-insect interactions. (author)
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Gamma irradiation on canola seeds affects herbivore-plant and host-parasitoid interactions
Energy Technology Data Exchange (ETDEWEB)
Akandeh, M.; Kocheili, F.; Rasekh, A. [Dept. of Entomology, Shahid Chamran Univ of Ahvaz (Iran, Islamic Republic of); Soufbaf, M., E-mail: msoufbaf@nrcam.org [Agricultural, Medical and Industrial Research School, Karaj (Iran, Islamic Republic of)
2017-06-15
As an agricultural modernization, gamma irradiation is an important method for enhancing crop yield and quality. Nevertheless, its use can alter other plant traits such as nutrition and resistance to different biotic/abiotic stresses that consequently affect plant-insect interactions. A tritrophic system was utilized based on two canola mutant lines produced through gamma irradiation (RGS 8-1 and Talaye 8-3). Plutella xylostella (L.), as a worldwide pest of Brassicaceae and Cotesia vestalis (Holiday) as a key biocontrol agent of P. xylostella were examined for the potential indirect effects of canola seed irradiation on the experimental insects' performance when acting on the respective mutant lines. This study showed that physical mutation did not affect plant nitrogen and herbivore-damaged total phenolics; however, phenolic compounds showed greater concentration in damaged leaves than undamaged leaves of both mutant and control plants. The relative growth rate and pupal weight of P. xylostella reared on RGS 8-1 were significantly higher than those reared on the control RGS. There was no significant difference by performance parameters of the parasitoid, C. vestalis, including total pre-oviposition period, adult longevity, adult fresh body weight of males and females, pupal weight, forewing area, and total longevity of both sexes on tested canola cultivars in comparison with their mutant lines. Life table parameters of C. vestalis on mutant lines of both cultivars, RGS and Talaye, were not significantly different from their control treatments. Comprehensive studies should be conducted to find out the mechanisms under which gamma rays affect plant-insect interactions. (author)
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Aboveground mechanical stimuli affect belowground plant-plant communication.
Elhakeem, Ali; Markovic, Dimitrije; Broberg, Anders; Anten, Niels P R; Ninkovic, Velemir
2018-01-01
Plants can detect the presence of their neighbours and modify their growth behaviour accordingly. But the extent to which this neighbour detection is mediated by abiotic stressors is not well known. In this study we tested the acclimation response of Zea mays L. seedlings through belowground interactions to the presence of their siblings exposed to brief mechano stimuli. Maize seedling simultaneously shared the growth solution of touched plants or they were transferred to the growth solution of previously touched plants. We tested the growth preferences of newly germinated seedlings toward the growth solution of touched (T_solution) or untouched plants (C_solution). The primary root of the newly germinated seedlings grew significantly less towards T_solution than to C_solution. Plants transferred to T_solution allocated more biomass to shoots and less to roots. While plants that simultaneously shared their growth solution with the touched plants produced more biomass. Results show that plant responses to neighbours can be modified by aboveground abiotic stress to those neighbours and suggest that these modifications are mediated by belowground interactions.
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Aboveground mechanical stimuli affect belowground plant-plant communication.
Directory of Open Access Journals (Sweden)
Ali Elhakeem
Full Text Available Plants can detect the presence of their neighbours and modify their growth behaviour accordingly. But the extent to which this neighbour detection is mediated by abiotic stressors is not well known. In this study we tested the acclimation response of Zea mays L. seedlings through belowground interactions to the presence of their siblings exposed to brief mechano stimuli. Maize seedling simultaneously shared the growth solution of touched plants or they were transferred to the growth solution of previously touched plants. We tested the growth preferences of newly germinated seedlings toward the growth solution of touched (T_solution or untouched plants (C_solution. The primary root of the newly germinated seedlings grew significantly less towards T_solution than to C_solution. Plants transferred to T_solution allocated more biomass to shoots and less to roots. While plants that simultaneously shared their growth solution with the touched plants produced more biomass. Results show that plant responses to neighbours can be modified by aboveground abiotic stress to those neighbours and suggest that these modifications are mediated by belowground interactions.
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Methane transport and emissions from soil as affected by water table and vascular plants
Bhullar, Gurbir S; Iravani, Majid; Edwards, Peter J; Olde Venterink, Harry
2013-01-01
Background: The important greenhouse gas (GHG) methane is produced naturally in anaerobic wetland soils. By affecting the production, oxidation and transport of methane to the atmosphere, plants have a major influence upon the quantities emitted by wetlands. Different species and functional plant groups have been shown to affect these processes differently, but our knowledge about how these effects are influenced by abiotic factors such as water regime and temperature remains limited. Here...
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Warming, CO2, and nitrogen deposition interactively affect a plant-pollinator mutualism.
Hoover, Shelley E R; Ladley, Jenny J; Shchepetkina, Anastasia A; Tisch, Maggie; Gieseg, Steven P; Tylianakis, Jason M
2012-03-01
Environmental changes threaten plant-pollinator mutualisms and their critical ecosystem service. Drivers such as land use, invasions and climate change can affect pollinator diversity or species encounter rates. However, nitrogen deposition, climate warming and CO(2) enrichment could interact to disrupt this crucial mutualism by altering plant chemistry in ways that alter floral attractiveness or even nutritional rewards for pollinators. Using a pumpkin model system, we show that these drivers non-additively affect flower morphology, phenology, flower sex ratios and nectar chemistry (sugar and amino acids), thereby altering the attractiveness of nectar to bumble bee pollinators and reducing worker longevity. Alarmingly, bees were attracted to, and consumed more, nectar from a treatment that reduced their survival by 22%. Thus, three of the five major drivers of global environmental change have previously unknown interactive effects on plant-pollinator mutualisms that could not be predicted from studies of individual drivers in isolation. © 2012 Blackwell Publishing Ltd/CNRS.
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International Nuclear Information System (INIS)
Rahola, T.; Albers, B.; Bergman, R.
1999-08-01
The research project EPORA (Effects of Industrial Pollution on the Distribution Dynamics of Radionuclides in Boreal Understorey Ecosystems) is part of the EU Nuclear Fission Safety Programme 1994 - 1998. The main purpose of EPORA is to study the influence of strong chemical pollution on the behaviour of artificial radionuclides ( 137 Cs, 90 Sr, 239 , 240 Pu ) in a northern boreal ecosystem and subsequently to assess the significance of the findings to the radiation exposure of the population in such areas. The present report is a documentation of the selection of study areas based on the assessment of available information on pollution in the Kola Peninsula and Northern Fennoscandia and of sampling and analysing methods. (orig.)
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The Salicylic Acid-Mediated Release of Plant Volatiles Affects the Host Choice of Bemisia tabaci
Directory of Open Access Journals (Sweden)
Xiaobin Shi
2016-06-01
Full Text Available The whitefly Bemisia tabaci (Gennadius (Hemiptera: Aleyrodidae causes serious crop losses worldwide by transmitting viruses. We have previously shown that salicylic acid (SA-related plant defenses directly affect whiteflies. In this study, we applied exogenous SA to tomato plants in order to investigate the interaction between SA-induced plant volatiles and nonviruliferous B. tabaci B and Q or B- and Q-carrying tomato yellow leaf curl virus (TYLCV. The results showed that exogenous SA caused plants to repel nonviruliferous whiteflies, but the effect was reduced when the SA concentration was low and when the whiteflies were viruliferous. Exogenous SA increased the number and quantity of plant volatiles—especially the quantity of methyl salicylate and δ-limonene. In Y-tube olfactometer assays, methyl salicylate and δ-limonene repelled the whiteflies, but the repellency was reduced for viruliferous Q. We suggest that the release of plant volatiles as mediated by SA affects the interaction between whiteflies, plants, and viruses. Further studies are needed to determine why viruliferous Q is less sensitive than nonviruliferous Q to repellent plant volatiles.
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ADP1 Affects Plant Architecture by Regulating Local Auxin Biosynthesis
Li, Shibai; Qin, Genji; Novák, Ondřej; Pěnčík, Aleš; Ljung, Karin; Aoyama, Takashi; Liu, Jingjing; Murphy, Angus; Gu, Hongya; Tsuge, Tomohiko; Qu, Li-Jia
2014-01-01
Plant architecture is one of the key factors that affect plant survival and productivity. Plant body structure is established through the iterative initiation and outgrowth of lateral organs, which are derived from the shoot apical meristem and root apical meristem, after embryogenesis. Here we report that ADP1, a putative MATE (multidrug and toxic compound extrusion) transporter, plays an essential role in regulating lateral organ outgrowth, and thus in maintaining normal architecture of Arabidopsis. Elevated expression levels of ADP1 resulted in accelerated plant growth rate, and increased the numbers of axillary branches and flowers. Our molecular and genetic evidence demonstrated that the phenotypes of plants over-expressing ADP1 were caused by reduction of local auxin levels in the meristematic regions. We further discovered that this reduction was probably due to decreased levels of auxin biosynthesis in the local meristematic regions based on the measured reduction in IAA levels and the gene expression data. Simultaneous inactivation of ADP1 and its three closest homologs led to growth retardation, relative reduction of lateral organ number and slightly elevated auxin level. Our results indicated that ADP1-mediated regulation of the local auxin level in meristematic regions is an essential determinant for plant architecture maintenance by restraining the outgrowth of lateral organs. PMID:24391508
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International Nuclear Information System (INIS)
1983-12-01
This report presents the results of a survey and evaluation of existing federal, state and local regulatory considerations affecting siting approval of power plants in the United States. Those factors that may impede early site approval of nuclear power plants are identified, and findings related to the removal of these impediments and the general improvement of the approval process are presented. A brief evaluation of standardization of nuclear plant design is also presented
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Directory of Open Access Journals (Sweden)
M. A. Manhães
Full Text Available Abstract The food habits and niche overlap based on diet composition and prey size of two species of understorey insectivorous birds were investigated in an area of montane rain forest in the state of Minas Gerais, southeastern Brazil. A total of 43 birds were captured: 33 individuals of Conopophaga lineata (Conopophagidae with 13 recaptures, and 10 individuals of Myiothlypis leucoblephara (Parulidae with 12 recaptures, from which were obtained respectively 33 and 10 fecal samples. Fragments of 16 groups of arthropods, plus insect eggs, were identified in these samples. Conopophaga lineata predominantly consumed Formicidae (32% and Isoptera (23.6%. However, the index of alimentary importance (AI of Isoptera (3.53 was lower than other groups such as Formicidae (AI = 61.88, Coleoptera (AI = 16.17, insect larvae (AI = 6.95 and Araneae (AI = 6.6. Myiothlypis leucoblephara predominantly consumed Formicidae (28.2% and Coleoptera (24.4%, although Coleoptera and Hymenoptera non-Formicidae had the highest values of AI (38.71 and 22.98 respectively. Differences in the proportions of the types of arthropods consumed by birds were not enough to reveal their separation into feeding niches (overlap = 0.618, p observed ≤ expected = 0.934, whereas differences in the use of resources was mainly due to the size of the prey (p<0.001, where C lineata, the species with the highest body mass (p<0.001 consumed larger prey. It is plausible that prey size is an axis of niche dimension that allows the coexistence of these species.
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[Dynamics of Amomum villosum growth and its fruit yield cultivated under tropical forests].
Zheng, Zheng; Gan, Jianmin; Feng, Zhili; Meng, Ying
2004-01-01
Investigations on the dynamics of Amomum villosum growth and its fruit yield cultivated under tropical ravine rainforest and secondary forest at different elevations in Xishuangbanna showed that the yield of A. villosum was influenced by the site age, sun light level of understorey, and water stress in dry season. The fruit yield and mature plant density decreased with increasing age of the A. villosum site. The fruit yield increased with sun light level when the light level in understorey was under 35% of full sun light (P forest was not significant. Planned cultivation of A. villosum in the secondary forest of the shifting cultivation land by ravine from 800-1000 m elevation instead of customary cultivation in the ravine rainforest, could not only resolve the problem of the effect of light deficiency in understorey and water stress in the dry season on A. villosum fruit yield, but also be useful to protect the tropical ravine rain forest.
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Veeken, van der A.J.H.; Lommen, W.J.M.
2009-01-01
Commercial potato minituber production systems aim at high tuber numbers per plant. This study investigated by which mechanisms planting density (25.0, 62.5 and 145.8 plants/m2) of in vitro derived plantlets affected minituber yield and minituber number per plantlet. Lowering planting density
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Fusarium oxysporum volatiles enhance plant growth via affecting auxin transport and signaling
Directory of Open Access Journals (Sweden)
Vasileios eBitas
2015-11-01
Full Text Available Volatile organic compounds (VOCs have well-documented roles in plant-plant communication and directing animal behavior. In this study, we examine the less understood roles of VOCs in plant-fungal relationships. Phylogenetically and ecologically diverse strains of Fusarium oxysporum, a fungal species complex that often resides in the rhizosphere of assorted plants, produce volatile compounds that augment shoot and root growth of Arabidopsis thaliana and tobacco. Growth responses of A. thaliana hormone signaling mutants and expression patterns of a GUS reporter gene under the auxin-responsive DR5 promoter supported the involvement of auxin signaling in F. oxysporum volatile-mediated growth enhancement. In addition, 1-naphthylthalamic acid, an inhibitor of auxin efflux, negated F. oxysporum volatile-mediated growth enhancement in both plants. Comparison of the profiles of volatile compounds produced by F. oxysporum strains that differentially affected plant growth suggests that the relative compositions of both growth inhibitory and stimulatory compounds may determine the degree of plant growth enhancement. Volatile-mediated signaling between fungi and plants may represent a potentially conserved, yet mostly overlooked, mechanism underpinning plant-fungus interactions and fungal niche adaption.
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Performance of 'Rocha' and 'Santa Maria' pears as affected by planting density
Directory of Open Access Journals (Sweden)
Mateus da Silveira Pasa
2015-02-01
Full Text Available The objective of this work was to evaluate the performance of 'Rocha' and 'Santa Maria' pears at two planting densities. The experiment was carried out during the 2011/2012, 2012/2013, and 2013/2014 growing seasons, in one-year-old orchards (2011/2012 of 'Rocha' and 'Santa Maria' pears, trained in a central-leader system and planted in two densities (2,000 and 4,000 trees per hectare. The assessed parameters were: production per hectare, production per tree, yield efficiency, number of fruit per tree, average fruit weight, trunk diameter increment, fruit firmness, and soluble solid contents. The cumulative yield of 'Rocha' is greater at the higher planting density, whereas the yield efficiency of 'Santa Maria' increases at the lower planting density, as the trees get more mature. Trunk diameter of 'Rocha' also increases at the lower planting density. However, fruit quality parameters in both cultivars are little affected by planting density.
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Ionizing radiation from Chernobyl affects development of wild carrot plants
Boratyński, Zbyszek; Arias, Javi Miranda; Garcia, Cristina; Mappes, Tapio; Mousseau, Timothy A.; Møller, Anders P.; Pajares, Antonio Jesús Muñoz; Piwczyński, Marcin; Tukalenko, Eugene
2016-12-01
Radioactivity released from disasters like Chernobyl and Fukushima is a global hazard and a threat to exposed biota. To minimize the deleterious effects of stressors organisms adopt various strategies. Plants, for example, may delay germination or stay dormant during stressful periods. However, an intense stress may halt germination or heavily affect various developmental stages and select for life history changes. Here, we test for the consequence of exposure to ionizing radiation on plant development. We conducted a common garden experiment in an uncontaminated greenhouse using 660 seeds originating from 33 wild carrots (Daucus carota) collected near the Chernobyl nuclear power plant. These maternal plants had been exposed to radiation levels that varied by three orders of magnitude. We found strong negative effects of elevated radiation on the timing and rates of seed germination. In addition, later stages of development and the timing of emergence of consecutive leaves were delayed by exposure to radiation. We hypothesize that low quality of resources stored in seeds, damaged DNA, or both, delayed development and halted germination of seeds from plants exposed to elevated levels of ionizing radiation. We propose that high levels of spatial heterogeneity in background radiation may hamper adaptive life history responses.
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Poisonous plants affecting the central nervous system of horses in Brazil
Poisoning by Indigofera pascuori was recently reported in horses in the state of Roraima. It causes chronic signs of sleepiness, unsteady gait, severe ataxia, and progressive weight loss. Some animals are blind. Young horses are more affected than adults. After the end of plant consumption the anima...
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International Nuclear Information System (INIS)
Frantál, Bohumil; Malý, Jiří
2017-01-01
Rebuilding and upgrading of existing nuclear power plants represent a great energy policy challenge today. In this paper, factors that affect local community support for the rebuilding of an existing nuclear power plant are explored using a regression analysis model. It is based on a survey involving nearly 600 residents of twelve municipalities located in the vicinity of the Dukovany power plant in the Czech Republic. Nearly two thirds of local population support the rebuilding of the plant. The support for rebuilding is not directly affected by distance of residence from the power plant or perceptions of its local economic impacts, but is more influenced by general perceptions of pros of nuclear power. Work in the power plant, perception of nuclear power as a clean energy contributing to climate change mitigation and negative attitude to the renewable energy development are strongest predictors of the support. In terms of energy policy implications, it seems that the education of the public and awareness of nuclear power plants as a clean, safe and landscape compatible system of energy production are more important for increasing acceptance of rebuilding projects than spatial distribution of economic benefits to local communities. - Highlights: • Predictors of support for nuclear power plant (NPP) rebuilding are explored. • Support is not affected by distance or perception of local economic impacts. • Support is affected by general perceptions of pros of NPPs. • Support is determined by perception of NPPs as a clean energy. • Support is correlated with a negative attitude to renewable energy promotion.
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Muehe, E. Marie; Weigold, Pascal; Adaktylou, Irini J.; Planer-Friedrich, Britta; Kraemer, Ute; Kappler, Andreas
2015-01-01
The remediation of metal-contaminated soils by phytoextraction depends on plant growth and plant metal accessibility. Soil microorganisms can affect the accumulation of metals by plants either by directly or indirectly stimulating plant growth and activity or by (im)mobilizing and/or complexing metals. Understanding the intricate interplay of metal-accumulating plants with their rhizosphere microbiome is an important step toward the application and optimization of phytoremediation. We compared the effects of a “native” and a strongly disturbed (gamma-irradiated) soil microbial communities on cadmium and zinc accumulation by the plant Arabidopsis halleri in soil microcosm experiments. A. halleri accumulated 100% more cadmium and 15% more zinc when grown on the untreated than on the gamma-irradiated soil. Gamma irradiation affected neither plant growth nor the 1 M HCl-extractable metal content of the soil. However, it strongly altered the soil microbial community composition and overall cell numbers. Pyrosequencing of 16S rRNA gene amplicons of DNA extracted from rhizosphere samples of A. halleri identified microbial taxa (Lysobacter, Streptomyces, Agromyces, Nitrospira, “Candidatus Chloracidobacterium”) of higher relative sequence abundance in the rhizospheres of A. halleri plants grown on untreated than on gamma-irradiated soil, leading to hypotheses on their potential effect on plant metal uptake. However, further experimental evidence is required, and wherefore we discuss different mechanisms of interaction of A. halleri with its rhizosphere microbiome that might have directly or indirectly affected plant metal accumulation. Deciphering the complex interactions between A. halleri and individual microbial taxa will help to further develop soil metal phytoextraction as an efficient and sustainable remediation strategy. PMID:25595759
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Color of illumination during growth affects LHCII chiral macroaggregates in pea plant leaves.
Gussakovsky, Eugene E; Shahak, Yosepha; Schroeder, Dana F
2007-02-01
To determine whether the color of illumination under which plants are grown, affects the structure of photosynthetic antennae, pea plants were grown under either blue-enriched, red-enriched, or white light. Carotenoid content of isolated chloroplasts was found to be insensitive to the color of illumination during growth, while chlorophyll a/b ratio in chloroplasts isolated from young illuminated leaves showed susceptibility to color. Color of illumination affects the LHCII chiral macroaggregates in intact leaves and isolated chloroplasts, providing light-induced alteration of the handedness of the LHCII chiral macroaggregate, as measured with circular dichroism and circularly polarized luminescence. The susceptibility of handedness to current illumination (red light excitation of chlorophyll fluorescence) is dependent on the color under which the plants were grown, and was maximal for the red-enriched illumination. We propose the existence of a long-term (growth period) color memory, which influences the susceptibility of the handedness of LHCII chiral macroaggregates to current light.
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Methane transport and emissions from soil as affected by water table and vascular plants.
Bhullar, Gurbir S; Iravani, Majid; Edwards, Peter J; Olde Venterink, Harry
2013-09-08
The important greenhouse gas (GHG) methane is produced naturally in anaerobic wetland soils. By affecting the production, oxidation and transport of methane to the atmosphere, plants have a major influence upon the quantities emitted by wetlands. Different species and functional plant groups have been shown to affect these processes differently, but our knowledge about how these effects are influenced by abiotic factors such as water regime and temperature remains limited. Here we present a mesocosm experiment comparing eight plant species for their effects on internal transport and overall emissions of methane under contrasting hydrological conditions. To quantify how much methane was transported internally through plants (the chimney effect), we blocked diffusion from the soil surface with an agar seal. We found that graminoids caused higher methane emissions than forbs, although the emissions from mesocosms with different species were either lower than or comparable to those from control mesocosms with no plant (i.e. bare soil). Species with a relatively greater root volume and a larger biomass exhibited a larger chimney effect, though overall methane emissions were negatively related to plant biomass. Emissions were also reduced by lowering the water table. We conclude that plant species (and functional groups) vary in the degree to which they transport methane to the atmosphere. However, a plant with a high capacity to transport methane does not necessarily emit more methane, as it may also cause more rhizosphere oxidation of methane. A shift in plant species composition from graminoids to forbs and/or from low to high productive species may lead to reduction of methane emissions.
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Institute of Scientific and Technical Information of China (English)
SHEN Wan-xia; Neil A Smith; ZHOU Chang-yong; WANG Ming-bo
2014-01-01
RNA silencing is a fundamental plant defence and gene control mechanism in plants that are directed by 20-24 nucleotide (nt) small interfering RNA (siRNA) and microRNA (miRNA). Infection of plants with viral pathogens or transformation of plants with RNA interference (RNAi) constructs is usually associated with high levels of exogenous siRNAs, but it is unclear if these siRNAs interfere with endogenous small RNA pathways and hence affect plant development. Here we provide evidence that viral satellite RNA (satRNA) infection does not affect siRNA and miRNA biogenesis or plant growth despite the extremely high level of satRNA-derived siRNAs. We generated transgenic Nicotiana benthamiana plants that no longer develop the speciifc yellowing symptoms generally associated with infection by Cucumber mosaic virus (CMV) Y-satellite RNA (Y-Sat). We then used these plants to show that CMV Y-Sat infection did not cause any visible phenotypic changes in comparison to uninfected plants, despite the presence of high-level Y-Sat siRNAs. Furthermore, we showed that the accumulation of hairpin RNA (hpRNA)-derived siRNAs or miRNAs, and the level of siRNA-directed transgene silencing, are not signiifcantly affected by CMV Y-Sat infection. Taken together, our results suggest that the high levels of exogenous siRNAs associated with viral infection or RNAi-inducing transgenes do not saturate the endogenous RNA silencing machineries and have no signiifcant impact on normal plant development.
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Lionetti, Vincenzo; Cervone, Felice; Bellincampi, Daniela
2012-11-01
The cell wall is a complex structure mainly composed by a cellulose-hemicellulose network embedded in a cohesive pectin matrix. Pectin is synthesized in a highly methyl esterified form and is de-esterified in muro by pectin methyl esterases (PMEs). The degree and pattern of methyl esterification affect the cell wall structure and properties with consequences on both the physiological processes of the plants and their resistance to pathogens. PME activity displays a crucial role in the outcome of the plant-pathogen interactions by making pectin more susceptible to the action of the enzymes produced by the pathogens. This review focuses on the impact of pectin methyl esterification in plant-pathogen interactions and on the dynamic role of its alteration during pathogenesis. Copyright © 2012 Elsevier GmbH. All rights reserved.
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A review study on medicinal plants affecting amnesia through cholinergic system
Directory of Open Access Journals (Sweden)
Baradaran Azar
2012-01-01
Full Text Available Neurotransmitter modification is an important method for the treatment of memory loss or amnesia. Cholinomimetic drugs, particularly, acetylcholine esterase inhibitors are the mainstream in pharmacotherapy of amnesia. Donepezil, tacrine, galantamine, and rivastigmine are cholinesterase inhibitors which are widely used in the treatment of amnesia, however, their therapeutic effects are not significant. Therefore, other possibilities including herbal medicine sources have been considered for memory loss therapy. There are some Medicinal plants with cholinomimetic property which mostly possess antioxidant activity, too. These plants may not only ameliorate amnesia but also can be a good source for drug discovery. In this paper other than introducing the medicinal plants and their components affective on cholinergic system and effective on memory loss, their probable advantages over synthetic drugs are discussed.
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International Nuclear Information System (INIS)
Wang, Zhenyu; Zhao, Xiuyang; Wang, Bing; Liu, Erlong; Chen, Ni; Zhang, Wei; Liu, Heng
2016-01-01
Heterogeneous nuclear ribonucleoproteins (hnRNPs) participate in diverse regulations of plant growth and environmental stress responses. In this work, an Arabidopsis hnRNP of unknown function, AtRNP1, was investigated. We found that AtRNP1 gene is highly expressed in rosette and cauline leaves, and slightly induced under drought, salt, osmotic and ABA stresses. AtRNP1 protein is localized to both the nucleus and cytoplasm. We performed homologous overexpression of AtRNP1 and found that the transgenic plants showed shortened root length and plant height, and accelerated flowering. In addition, the transgenic plants also showed reduced tolerance to drought, salt, osmotic and ABA stresses. Further studies revealed that under both normal and stress conditions, the proline contents in the transgenic plants are markedly decreased, associated with reduced expression levels of a proline synthase gene and several stress-responsive genes. These results suggested that the overexpression of AtRNP1 negatively affects plant growth and abiotic stress tolerance. - Highlights: • AtRNP1 is a widely expressed gene and its expression is slightly induced under abiotic stresses. • AtRNP1 protein is localized to both the nucleus and cytoplasm. • Overexpression of AtRNP1 affects plant growth. • Overexpression of AtRNP1 reduces plant tolerance to drought and salt stresses. • AtRNP1 overexpression plants show decreased proline accumulation and stress-responsive gene expressions.
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Energy Technology Data Exchange (ETDEWEB)
Wang, Zhenyu, E-mail: wzy72609@163.com [Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730030 (China); Zhao, Xiuyang, E-mail: xiuzh@psb.vib-ugent.be [Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730030 (China); Wang, Bing, E-mail: wangbing@ibcas.ac.cn [Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730030 (China); Liu, Erlong, E-mail: liuel14@lzu.edu.cn [Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730030 (China); Chen, Ni, E-mail: 63710156@qq.com [Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730030 (China); Zhang, Wei, E-mail: wzhang1216@yahoo.com [Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences, Shanghai University, Shanghai 200444 (China); Liu, Heng, E-mail: hengliu@lzu.edu.cn [Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730030 (China)
2016-04-01
Heterogeneous nuclear ribonucleoproteins (hnRNPs) participate in diverse regulations of plant growth and environmental stress responses. In this work, an Arabidopsis hnRNP of unknown function, AtRNP1, was investigated. We found that AtRNP1 gene is highly expressed in rosette and cauline leaves, and slightly induced under drought, salt, osmotic and ABA stresses. AtRNP1 protein is localized to both the nucleus and cytoplasm. We performed homologous overexpression of AtRNP1 and found that the transgenic plants showed shortened root length and plant height, and accelerated flowering. In addition, the transgenic plants also showed reduced tolerance to drought, salt, osmotic and ABA stresses. Further studies revealed that under both normal and stress conditions, the proline contents in the transgenic plants are markedly decreased, associated with reduced expression levels of a proline synthase gene and several stress-responsive genes. These results suggested that the overexpression of AtRNP1 negatively affects plant growth and abiotic stress tolerance. - Highlights: • AtRNP1 is a widely expressed gene and its expression is slightly induced under abiotic stresses. • AtRNP1 protein is localized to both the nucleus and cytoplasm. • Overexpression of AtRNP1 affects plant growth. • Overexpression of AtRNP1 reduces plant tolerance to drought and salt stresses. • AtRNP1 overexpression plants show decreased proline accumulation and stress-responsive gene expressions.
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Weldegergis, B.T.; Zhu, F.; Poelman, E.H.; Dicke, M.
2015-01-01
One of the main abiotic stresses that strongly affects plant survival and the primary cause of crop loss around the world is drought. Drought stress leads to sequential morphological, physiological, biochemical and molecular changes that can have severe effects on plant growth, development and
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Energy Technology Data Exchange (ETDEWEB)
Carleton, T.J.; Gordon, A.M.
1992-01-01
In summer 1991, a variety of forest stands dominated by old specimens of white pine and red pine were sampled across a representative portion of the species' range in northcentral Ontario. Plots were established in 40 stands of those surveyed to identify the salient structural components of old-growth, to survey the floristic composition (vascular plants and autotrophic non- vascular plants), to survey site characteristics, and to estimate the links in understorey alpha diversity with site conditions and stand structure. Long-term objectives include a definition of old- growth pine forest, recognition criteria, and prospective management options. Forest stand structure was enumerated through mapping, mensurational, and age estimation techniques. Forest vegetation, including over and understorey species, was non- destructively sampled and a range of data on stand and soil-site variables was also collected in conjunction with information on stand variables peculiar to old growth forests.
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região da floresta estacional decidual do rio grande do sul
Directory of Open Access Journals (Sweden)
Franz H. Andrae
2005-01-01
Full Text Available In the central part of Rio Grande do Sul State understoreys of 12 stands of Pinus sp. and one of Araucaria angustifolia O.Ktze were studied, all growing on soils, degraded by agriculture. One pine stand, 10 years old, originated from a natural renovation, the others had been planted 25 to 30 years ago, Araucaria was seeded directly. A total of 575 plots were sampled, 25 m² each, distributed systematically within the stands. Measurements included pines overstorey, and all understorey woody species, separeted into layers of more than 1,3 m high and 1,3 to 0,3 m; the layer lower than 0,3 m included only natural renovation of pines. Understoreys were composed by 121 species, ocurring common and high value timber species, ornamental trees, native and exotic fruit tree species. A higher number of species was present with a very few individuals only. The presence of non woody species like grasses, herbs, ferns and lians also was quantified. The number of tree species and the presence of non woody species did not correlat with density of overstorey pines. Abundance and frequency of species showed no significant diferences, when samples were grouped according to their location in the center or close to stands edge. Distribution pattern of understorey trees within stands was quantified, using Cox index, species diversity was compared by means of Shannon-index. Similarity of stands was compared by Sörensen-Index. It was concluded, that exotic species planted on poor agricultural soil may not only be of farmers interest because of their high potential for wood production. These plantations also may be considered from conservationist point of view, since they show an unexpected high diversity, so contributing in a longer run to landscape improvement, possibly due to the small extension of stands.
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Energy Technology Data Exchange (ETDEWEB)
Rahola, T. [Radiation and Nuclear Safety Authority, Helsinki (Finland); Albers, B. [National Research Center for Environmental and Health (Georgia); Bergman, R. [National Defence Research Establishment (Germany)] [and others
1999-08-01
The research project EPORA (Effects of Industrial Pollution on the Distribution Dynamics of Radionuclides in Boreal Understorey Ecosystems) is part of the EU Nuclear Fission Safety Programme 1994 - 1998. The main purpose of EPORA is to study the influence of strong chemical pollution on the behaviour of artificial radionuclides ({sup 137}Cs,{sup 90}Sr, {sup 239},{sup 240}{sub Pu}) in a northern boreal ecosystem and subsequently to assess the significance of the findings to the radiation exposure of the population in such areas. The present report is a documentation of the selection of study areas based on the assessment of available information on pollution in the Kola Peninsula and Northern Fennoscandia and of sampling and analysing methods. (orig.)
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Selmants, Paul C; Zavaleta, Erika S; Wolf, Amelia A
2014-01-01
Numerous experiments have demonstrated that diverse plant communities use nitrogen (N) more completely and efficiently, with implications for how species conservation efforts might influence N cycling and retention in terrestrial ecosystems. However, most such experiments have randomly manipulated species richness and minimized environmental heterogeneity, two design aspects that may reduce applicability to real ecosystems. Here we present results from an experiment directly comparing how realistic and randomized plant species losses affect plant N use across a gradient of soil depth in a native-dominated serpentine grassland in California. We found that the strength of the species richness effect on plant N use did not increase with soil depth in either the realistic or randomized species loss scenarios, indicating that the increased vertical heterogeneity conferred by deeper soils did not lead to greater complementarity among species in this ecosystem. Realistic species losses significantly reduced plant N uptake and altered N-use efficiency, while randomized species losses had no effect on plant N use. Increasing soil depth positively affected plant N uptake in both loss order scenarios but had a weaker effect on plant N use than did realistic species losses. Our results illustrate that realistic species losses can have functional consequences that differ distinctly from randomized losses, and that species diversity effects can be independent of and outweigh those of environmental heterogeneity on ecosystem functioning. Our findings also support the value of conservation efforts aimed at maintaining biodiversity to help buffer ecosystems against increasing anthropogenic N loading.
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How glyphosate affects plant disease development: it is more than enhanced susceptibility.
Hammerschmidt, Ray
2018-05-01
Glyphosate has been shown to affect the development of plant disease in several ways. Plants utilize phenolic and other shikimic acid pathway-derived compounds as part of their defense against pathogens, and glyphosate inhibits the biosynthesis of these compounds via its mode of action. Several studies have shown a correlation between enhanced disease and suppression of phenolic compound production after glyphosate. Glyphosate-resistant crop plants have also been studied for changes in resistance as a result of carrying the glyphosate resistance trait. The evidence indicates that neither the resistance trait nor application of glyphosate to glyphosate-resistant plants increases susceptibility to disease. The only exceptions to this are cases where glyphosate has been shown to reduce rust diseases on glyphosate-resistant crops, supporting a fungicidal role for this chemical. Finally, glyphosate treatment of weeds or volunteer crops can cause a temporary increase in soil-borne pathogens that may result in disease development if crops are planted too soon after glyphosate application. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.
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Debout, Gabriel; Provost, Erick; Renucci, Marielle; Tirard, Alain; Schatz, Bertrand; McKey, Doyle
2003-10-01
Social organisation of colonies of obligate plant-ants can affect their interaction with myrmecophyte hosts and with other ants competing for the resources they offer. An important parameter of social organisation is whether nest sites of a colony include one or several host individuals. We determined colony boundaries in a plant-ant associated with the rainforest understorey tree Leonardoxa africana subsp. africana, found in coastal forests of Cameroon (Central Africa). This myrmecophyte is strictly associated with two ants, Petalomyrmex phylax and Cataulacus mckeyi. Plants provide food and nesting sites for P. phylax, which protects young leaves against insect herbivores. This mutualism is often parasitised by C. mckeyi, which uses but does not protect the host. The presence of C. mckeyi on a tree excludes the mutualistic ant. Because Petalomyrmex-occupied trees are better protected, their growth and survival are superior to those of Cataulacus-occupied trees, giving P. phylax an advantage in occupation of nest sites. C. mckeyi often colonises trees that have lost their initial associate P. phylax, as a result of injury to the tree caused by disturbance. Polydomy may allow C. mckeyi to occupy small clumps of trees, without the necessity of claustral colony foundation in each tree. Investigating both the proximate (behavioural repertoire, colony odour) and the ultimate factors (genetic structure) that may influence colony closure, we precisely defined colony boundaries. We show that colonies of C. mckeyi are monogynous and facultatively polydomous, i.e. a colony occupies one to several Leonardoxa trees. Workers do not produce males. Thus, the hypothesis that polydomy allows workers in queenless nests to evade queen control for their reproduction is not supported in this instance. This particular colony structure may confer on C. mckeyi an advantage in short-distance dispersal, and this could help explain its persistence within the dynamic Leonardoxa system.
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Fischer, Christine; Roscher, Christiane; Jensen, Britta; Eisenhauer, Nico; Baade, Jussi; Attinger, Sabine; Scheu, Stefan; Weisser, Wolfgang W; Schumacher, Jens; Hildebrandt, Anke
2014-01-01
Infiltration is a key process in determining the water balance, but so far effects of earthworms, soil texture, plant species diversity and their interaction on infiltration capacity have not been studied. We measured infiltration capacity in subplots with ambient and reduced earthworm density nested in plots of different plant species (1, 4, and 16 species) and plant functional group richness and composition (1 to 4 groups; legumes, grasses, small herbs, tall herbs). In summer, earthworm presence significantly increased infiltration, whereas in fall effects of grasses and legumes on infiltration were due to plant-mediated changes in earthworm biomass. Effects of grasses and legumes on infiltration even reversed effects of texture. We propose two pathways: (i) direct, probably by modifying the pore spectrum and (ii) indirect, by enhancing or suppressing earthworm biomass, which in turn influenced infiltration capacity due to change in burrowing activity of earthworms. Overall, the results suggest that spatial and temporal variations in soil hydraulic properties can be explained by biotic processes, especially the presence of certain plant functional groups affecting earthworm biomass, while soil texture had no significant effect. Therefore biotic parameters should be taken into account in hydrological applications.
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Responses to ammonium and nitrate additions by boreal plants and their natural enemies
International Nuclear Information System (INIS)
Nordin, Annika; Strengbom, Joachim; Ericson, Lars
2006-01-01
Separate effects of ammonium (NH 4 + ) and nitrate (NO 3 - ) on boreal forest understorey vegetation were investigated in an experiment where 12.5 and 50.0 kg nitrogen (N) ha -1 year -1 was added to 2 m 2 sized plots during 4 years. The dwarf-shrubs dominating the plant community, Vaccinium myrtillus and V. vitis-idaea, took up little of the added N independent of the chemical form, and their growth did not respond to the N treatments. The grass Deschampsia flexuosa increased from the N additions and most so in response to NO 3 - . Bryophytes took up predominately NH 4 + and there was a negative correlation between moss N concentration and abundance. Plant pathogenic fungi increased from the N additions, but showed no differences in response to the two N forms. Because the relative contribution of NH 4 + and NO 3 - to the total N deposition on a regional scale can vary substantially, the N load a habitat can sustain without substantial changes in the biota should be set considering specific vegetation responses to the predominant N form in deposition. - Biota will respond to nitrogen deposition depending on the form of nitrogen
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Invasive plants affect prairie soil biology
Non-native or exotic plants often cause ecological and environmental damage in ecosystems where they invade and become established. These invasive plants may be the most serious threat to plant diversity in prairies, especially those in scattered remnants, which may be particularly vulnerable to rap...
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Sporulation of Phytophthora ramorum and P. kernoviae on asymptomatic foliage and fruit
S. Denman; E. Moralejo; S.A. Kirk; E. Orton; A. Whybrow
2008-01-01
Phytophthora ramorum and P. kernoviae are newly discovered invasive Phytophthoras causing leaf necrosis, shoot tip dieback (mostly on ornamental and forest understorey host species) and bleeding cankers on tree trunks of a wide range of plant species. Both pathogens are now present in south-west England....
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Zheng, S.J.; Snoeren, T.A.L.; Hogewoning, S.W.; Loon, van J.J.A.; Dicke, M.
2010-01-01
Optical plant characteristics are important cues to plant-feeding insects. In this article, we demonstrate for the first time that silencing the phytoene desaturase (PDS) gene, encoding a key enzyme in plant carotenoid biosynthesis, affects insect oviposition site selection behaviour. Virus-induced
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Miller, Robert J.; Lafferty, Kevin D.; Lamy, Thomas; Kui, Li; Rassweiler, Andrew; Reed, Daniel C.
2018-01-01
Foundation species define the ecosystems they live in, but ecologists have often characterized dominant plants as foundational without supporting evidence. Giant kelp has long been considered a marine foundation species due to its complex structure and high productivity; however, there is little quantitative evidence to evaluate this. Here, we apply structural equation modelling to a 15-year time series of reef community data to evaluate how giant kelp affects the reef community. Although species richness was positively associated with giant kelp biomass, most direct paths did not involve giant kelp. Instead, the foundational qualities of giant kelp were driven mostly by indirect effects attributed to its dominant physical structure and associated engineering influence on the ecosystem, rather than by its use as food by invertebrates and fishes. Giant kelp structure has indirect effects because it shades out understorey algae that compete with sessile invertebrates. When released from competition, sessile species in turn increase the diversity of mobile predators. Sea urchin grazing effects could have been misinterpreted as kelp effects, because sea urchins can overgraze giant kelp, understorey algae and sessile invertebrates alike. Our results confirm the high diversity and biomass associated with kelp forests, but highlight how species interactions and habitat attributes can be misconstrued as direct consequences of a foundation species like giant kelp.
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Andriuzzi, Walter; Schmidt, Olaf; Brussaard, L.; Faber, J.H.; Bolger, T.
2016-01-01
We performed a greenhouse experiment to test how the functional diversity of earthworms, the dominant group of soil macro-invertebrates in many terrestrial ecosystems, affects nitrogen cycling and plant growth. Three species were chosen to represent a range of functional traits: Lumbricus terrestris
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Directory of Open Access Journals (Sweden)
Christine Fischer
Full Text Available BACKGROUND: Infiltration is a key process in determining the water balance, but so far effects of earthworms, soil texture, plant species diversity and their interaction on infiltration capacity have not been studied. METHODOLOGY/PRINCIPAL FINDINGS: We measured infiltration capacity in subplots with ambient and reduced earthworm density nested in plots of different plant species (1, 4, and 16 species and plant functional group richness and composition (1 to 4 groups; legumes, grasses, small herbs, tall herbs. In summer, earthworm presence significantly increased infiltration, whereas in fall effects of grasses and legumes on infiltration were due to plant-mediated changes in earthworm biomass. Effects of grasses and legumes on infiltration even reversed effects of texture. We propose two pathways: (i direct, probably by modifying the pore spectrum and (ii indirect, by enhancing or suppressing earthworm biomass, which in turn influenced infiltration capacity due to change in burrowing activity of earthworms. CONCLUSIONS/SIGNIFICANCE: Overall, the results suggest that spatial and temporal variations in soil hydraulic properties can be explained by biotic processes, especially the presence of certain plant functional groups affecting earthworm biomass, while soil texture had no significant effect. Therefore biotic parameters should be taken into account in hydrological applications.
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Oguntimehin, Ilemobayo; Eissa, Fawzy; Sakugawa, Hiroshi
2010-02-01
Cherry tomato plants (Lycopersicon esculentum Mill) were sprayed with fluoranthene and mixture of fluoranthene and mannitol solutions for 30d. The exposure was carried out in growth chambers in field conditions, and the air was filtered through charcoal filters to remove atmospheric contaminants. Plants were sprayed with 10microM fluoranthene as mist until they reached the fruiting stage, and the eco-physiological parameters were measured to determine the effects of the treatments. We measured CO(2) uptake and water vapour exchange, chlorophyll fluorescence, leaf pigment contents, visual symptoms and biomass allocation. Fluoranthene which was deposited as mist onto leaves negatively affected both growth and the quality of tomato plants, while other treatments did not. The photosynthetic rate measured at saturated irradiance was approximately 37% lower in fluoranthene-treated plants compared with the control group. Other variables, such as stomata conductance, the photochemical efficiency of PSII in the dark, Chl a, Chl b, and the total chlorophyll contents of the tomato leaves were significantly reduced in the fluoranthene-treated plants. Tomato plants treated with fluoranthene showed severe visible injury symptoms on the foliage during the exposure period. Mannitol (a reactive oxygen scavenger) mitigated effects of fluoranthene; thus, reactive oxygen species generated through fluoranthene may be responsible for the damaged tomato plants. It is possible for fluoranthene to decrease the aesthetic and hence the economic value of this valuable crop plant. 2009 Elsevier Ltd. All rights reserved.
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Carbon Stock in Integrated Field Laboratory Faculty of Agriculture University of Lampung
Directory of Open Access Journals (Sweden)
Irwan Sukri Banuwa
2016-05-01
Full Text Available This study aimed to determine the amount of carbon stock and CO2 plant uptake in the Integrated Field Laboratory (IFL Faculty of Agriculture University of Lampung. The research was conducted from April to November 2015. The study was arranged in a completely randomized block design (CRBD, consisting of five land units as treatment with four replications for each treatment. Biomass of woody plants was estimated using allometric equation, biomass of understorey plants was estimated using plant dry weight equation, and organic C content in plants and soils were analyzed using a Walkey and Black method. The results showed that land unit consisting of densely woody plants significantly affects total biomass of woody plants, organic C content in woody plants and total carbon content (above and below ground. The highest amount of woody plant biomass was observed in land unit 5, i.e. 1,196.88 Mg ha-1, and above ground total carbon was 437.19 Mg ha-1. IFL Faculty of Agriculture University of Lampung has a total carbon stock of 2,051.90 Mg and capacity to take up total CO2 of 6,656.88 Mg.
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Soleymani, A
2017-08-01
Crop response to light is an important parameter determining crop growth. Three field (split plots) experiments were conducted to investigate the effects of plant density, plant genotype and N fertilization on the light absorption and light extinction of sunflower (Helianthus annuus L.) and canola (Brassica napus L.). A detailed set of plant growth, light absorption and crop yield and oil related parameters were determined. Light was measured at noon during the sunny days with clear sky. In experiment I, although the plant density (PD) of 14 resulted in the highest rate of sunflower light absorption (31.37%) and light extinction (0.756), the highest rate of grain yield and grain oil yield was resulted at PD12 at 3639 and 1457.9kg/ha, respectively; as well as by genotype SUP.A. In experiment II (canola), PD80 resulted in the highest rate of light absorption (13.13%), light extinction (0.63), grain yield (2189.4kg/ha) and grain oil yield (556.54kg/ha). This was also the case for Genotype H. In experiment III (canola), although N150 resulted in the highest rate of light absorption (10.74%) and light extinction (0.48), the highest rate of grain yield (3413.6kg/ha) and grain oil yield (891.86kg/ha) was resulted at N100 as well as by Genotype H401. Results indicate how light properties, crop growth and yield of sunflower and canola can be affected by plant and environmental parameters, which are also of practical use by farmers. Copyright © 2017 Elsevier B.V. All rights reserved.
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Directory of Open Access Journals (Sweden)
Stephanie Stiegel
2018-01-01
Full Text Available Environmental and leaf trait effects on herbivory are supposed to vary among different feeding guilds. Herbivores also show variability in their preferences for plant ontogenetic stages. Along the vertical forest gradient, environmental conditions change, and trees represent juvenile and adult individuals in the understorey and canopy, respectively. This study was conducted in ten forests sites in Central Germany for the enrichment of canopy research in temperate forests. Arthropod herbivory of different feeding traces was surveyed on leaves of Fagus sylvatica Linnaeus (European beech; Fagaceae in three strata. Effects of microclimate, leaf traits, and plant ontogenetic stage were analyzed as determining parameters for herbivory. The highest herbivory was caused by exophagous feeding traces. Herbivore attack levels varied along the vertical forest gradient for most feeding traces with distinct patterns. If differences of herbivory levels were present, they only occurred between juvenile and adult F. sylvatica individuals, but not between the lower and upper canopy. In contrast, differences of microclimate and important leaf traits were present between the lower and upper canopy. In conclusion, the plant ontogenetic stage had a stronger effect on herbivory than microclimate or leaf traits along the vertical forest gradient.
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Heavy metal leaching from mine tailings as affected by plants
Energy Technology Data Exchange (ETDEWEB)
Zhu, D.; Schwab, A.P.; Banks, M.K.
1999-12-01
A column experiment was conducted to determine the impact of soil cover and plants on heavy metal leaching from mine tailings and heavy metal contaminated soil. Columns made of PVC were constructed with 30 cm subsoil covered by 30 cm of mine tailings followed by 0, 30, or 60 cm subsoil covered by 30 cm of mine tailings followed by 0, 30, or 60 cm of clean topsoil. Two grasses, tall fescue (Festuca arundinacea Schreb.) and big bluestem (Andropogon gerardii), were grown in the columns. The columns were leached at a slow rate for 1 yr with a 0.001 M CaCl{sub 2} solution under unsaturated conditions. The presence of both tall fescue and big bluestem increased Zn and Cd concentrations in the leachate. Lead concentrations in leachates were not affected by the presence of plants. Although plants generally reduced the total amount of water leached, total mass of Zn and Cd leached generally was not impacted by plants. Total mass of Pb leached was positively correlated with total leachate collected from each column. Covering the mine tailings with 60 cm of topsoil increased the mass of Zn and Cd leached relative to no topsoil. When the subsoil was absent, Zn and Cd leaching increased by as much as 20-fold, verifying the ability of soil to act as a sink for metals. Mine tailing remediation by establishing vegetation can reduce Pb movement but may enhance short-term Cd and Zn leaching. However, the changes were relatively small and do not outweigh the benefits of using vegetation in mine tailings reclamation.
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Spatial environmental heterogeneity affects plant growth and thermal performance on a green roof
Energy Technology Data Exchange (ETDEWEB)
Buckland-Nicks, Michael; Heim, Amy; Lundholm, Jeremy, E-mail: jlundholm@smu.ca
2016-05-15
Green roofs provide ecosystem services, including stormwater retention and reductions in heat transfer through the roof. Microclimates, as well as designed features of green roofs, such as substrate and vegetation, affect the magnitude of these services. Many green roofs are partially shaded by surrounding buildings, but the effects of this within-roof spatial environmental heterogeneity on thermal performance and other ecosystem services have not been examined. We quantified the effects of spatial heterogeneity in solar radiation, substrate depth and other variables affected by these drivers on vegetation and ecosystem services in an extensive green roof. Spatial heterogeneity in substrate depth and insolation were correlated with differential growth, survival and flowering in two focal plant species. These effects were likely driven by the resulting spatial heterogeneity in substrate temperature and moisture content. Thermal performance (indicated by heat flux and substrate temperature) was influenced by spatial heterogeneity in vegetation cover and substrate depth. Areas with less insolation were cooler in summer and had greater substrate moisture, leading to more favorable conditions for plant growth and survival. Spatial variation in substrate moisture (7%–26% volumetric moisture content) and temperature (21 °C–36 °C) during hot sunny conditions in summer could cause large differences in stormwater retention and heat flux within a single green roof. Shaded areas promote smaller heat fluxes through the roof, leading to energy savings, but lower evapotranspiration in these areas should reduce stormwater retention capacity. Spatial heterogeneity can thus result in trade-offs between different ecosystem services. The effects of these spatial heterogeneities are likely widespread in green roofs. Structures that provide shelter from sun and wind may be productively utilized to design higher functioning green roofs and increase biodiversity by providing habitat
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Spatial environmental heterogeneity affects plant growth and thermal performance on a green roof
International Nuclear Information System (INIS)
Buckland-Nicks, Michael; Heim, Amy; Lundholm, Jeremy
2016-01-01
Green roofs provide ecosystem services, including stormwater retention and reductions in heat transfer through the roof. Microclimates, as well as designed features of green roofs, such as substrate and vegetation, affect the magnitude of these services. Many green roofs are partially shaded by surrounding buildings, but the effects of this within-roof spatial environmental heterogeneity on thermal performance and other ecosystem services have not been examined. We quantified the effects of spatial heterogeneity in solar radiation, substrate depth and other variables affected by these drivers on vegetation and ecosystem services in an extensive green roof. Spatial heterogeneity in substrate depth and insolation were correlated with differential growth, survival and flowering in two focal plant species. These effects were likely driven by the resulting spatial heterogeneity in substrate temperature and moisture content. Thermal performance (indicated by heat flux and substrate temperature) was influenced by spatial heterogeneity in vegetation cover and substrate depth. Areas with less insolation were cooler in summer and had greater substrate moisture, leading to more favorable conditions for plant growth and survival. Spatial variation in substrate moisture (7%–26% volumetric moisture content) and temperature (21 °C–36 °C) during hot sunny conditions in summer could cause large differences in stormwater retention and heat flux within a single green roof. Shaded areas promote smaller heat fluxes through the roof, leading to energy savings, but lower evapotranspiration in these areas should reduce stormwater retention capacity. Spatial heterogeneity can thus result in trade-offs between different ecosystem services. The effects of these spatial heterogeneities are likely widespread in green roofs. Structures that provide shelter from sun and wind may be productively utilized to design higher functioning green roofs and increase biodiversity by providing habitat
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Does a decade of elevated [CO2] affect a desert perennial plant community?
Newingham, Beth A; Vanier, Cheryl H; Kelly, Lauren J; Charlet, Therese N; Smith, Stanley D
2014-01-01
Understanding the effects of elevated [CO2 ] on plant community structure is crucial to predicting ecosystem responses to global change. Early predictions suggested that productivity in deserts would increase via enhanced water-use efficiency under elevated [CO2], but the response of intact arid plant communities to elevated [CO2 ] is largely unknown. We measured changes in perennial plant community characteristics (cover, species richness and diversity) after 10 yr of elevated [CO2] exposure in an intact Mojave Desert community at the Nevada Desert Free-Air CO2 Enrichment (FACE) Facility. Contrary to expectations, total cover, species richness, and diversity were not affected by elevated [CO2]. Over the course of the experiment, elevated [CO2] had no effect on changes in cover of the evergreen C3 shrub, Larrea tridentata; alleviated decreases in cover of the C4 bunchgrass, Pleuraphis rigida; and slightly reduced the cover of C3 drought-deciduous shrubs. Thus, we generally found no effect of elevated [CO2] on plant communities in this arid ecosystem. Extended drought, slow plant growth rates, and highly episodic germination and recruitment of new individuals explain the lack of strong perennial plant community shifts after a decade of elevated [CO2]. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.
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Methods of affecting nitrogen assimilation in plants
Energy Technology Data Exchange (ETDEWEB)
Coruzzi, Gloria; Gutierrez, Rodrigo A.; Nero, Damion C.
2016-10-11
Provided herein are compositions and methods for producing transgenic plants. In specific embodiments, transgenic plants comprise a construct comprising a polynucleotide encoding CCA1, GLK1 or bZIP1, operably linked to a plant-specific promote, wherein the CCA1, GLK1 or bZIP1 is ectopically overexpressed in the transgenic plants, and wherein the promoter is optionally a constitutive or inducible promoter. In other embodiments, transgenic plants in which express a lower level of CCA1, GLK1 or bZIP1 are provided. Also provided herein are commercial products (e.g., pulp, paper, paper products, or lumber) derived from the transgenic plants (e.g., transgenic trees) produced using the methods provided herein.
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Lopisso, Daniel Teshome; Knüfer, Jessica; Koopmann, Birger; von Tiedemann, Andreas
2017-04-01
Verticillium longisporum is a host-specific vascular pathogen of oilseed rape (Brassica napus L.) that causes economic crop losses by impairing plant growth and inducing premature senescence. This study investigates whether plant damage through Verticillium stem striping is due to impaired plant water relations, whether V. longisporum affects responses of a susceptible B. napus variety to drought stress, and whether drought stress, in turn, affects plant responses to V. longisporum. Two-factorial experiments on a susceptible cultivar of B. napus infected or noninfected with V. longisporum and exposed to three watering levels (30, 60, and 100% field capacity) revealed that drought stress and V. longisporum impaired plant growth by entirely different mechanisms. Although both stresses similarly affected plant growth parameters (plant height, hypocotyl diameter, and shoot and root dry matter), infection of B. napus with V. longisporum did not affect any drought-related physiological or molecular genetic plant parameters, including transpiration rate, stomatal conductance, photosynthesis rate, water use efficiency, relative leaf water content, leaf proline content, or the expression of drought-responsive genes. Thus, this study provides comprehensive physiological and molecular genetic evidence explaining the lack of wilt symptoms in B. napus infected with V. longisporum. Likewise, drought tolerance of B. napus was unaffected by V. longisporum, as was the level of disease by drought conditions, thus excluding a concerted action of both stresses in the field. Although it is evident that drought and vascular infection with V. longisporum impair plant growth by different mechanisms, it remains to be determined by which other factors V. longisporum causes crop loss.
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Directory of Open Access Journals (Sweden)
Fernanda da Silva Mendes
2013-06-01
Full Text Available http://dx.doi.org/10.5902/198050989283The structure dynamics of an understorey vegetation influenced by gaps caused by reduced impact logging was analyzed during 12 years in a solid ground rain forest in the municipality of Moju, Pará state, eastern Brazilian Amazon forest. Angiosperm individuals from 10 cm height up to 5 cm DBH were surveyed in a 468 m² sample area in six occasions (1998, 1999, 2000, 2001, 2007 and 2010, they were analyzed considering their life-forms (trees, shrub, lianas, herbs and palms, abundance, frequency, size classes (CT1 = 10 cm ≤ HT < 50 cm; CT2 = 50 cm ≤ HT < 130 cm; CT3 = 130 cm < HT and DAP < 2 cm; and CT4 = 2 cm ≤ DAP < 5 cm and relative natural regeneration Burseraceae, Marantaceae, Violaceae and Lecythidaceae were the most important families in the study area in every occasions, while the most representative species were Monotagma sp1., Monotagma sp2., Rinorea guianensis, Lecythis idatimon e Protium pilosum. The most frequent life forms were trees, herbs and lianas in all occasions. The dynamics of life forms depended on light intensity. The establishment of commercial and potentially commercial species was favored by gaps, suggesting that natural regeneration of those species do not need to be assisted for guaranteeing timber stocks for future harvests.
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Nawab, Javed; Khan, Sardar; Shah, Mohammad Tahir; Khan, Kifayatullah; Huang, Qing; Ali, Roshan
2015-01-01
Several anthropogenic and natural sources are considered as the primary sources of toxic metals in the environment. The current study investigates the level of heavy metals contamination in the flora associated with serpentine soil along the Mafic and Ultramafic rocks northern-Pakistan. Soil and wild native plant species were collected from chromites mining affected areas and analyzed for heavy metals (Cr, Ni, Fe, Mn, Co, Cu and Zn) using atomic absorption spectrometer (AAS-PEA-700). The heavy metal concentrations were significantly (p soil as compared to reference soil, however Cr and Ni exceeded maximum allowable limit (250 and 60 mg kg(-1), respectively) set by SEPA for soil. Inter-metal correlations between soil, roots and shoots showed that the sources of contamination of heavy metals were mainly associated with chromites mining. All the plant species accumulated significantly higher concentrations of heavy metals as compared to reference plant. The open dumping of mine wastes can create serious problems (food crops and drinking water contamination with heavy metals) for local community of the study area. The native wild plant species (Nepeta cataria, Impatiens bicolor royle, Tegetis minuta) growing on mining affected sites may be used for soil reclamation contaminated with heavy metals.
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Kurm, Viola; van der Putten, Wim H; Pineda, Ana; Hol, W H Gera
2018-02-12
Plant growth-promoting rhizobacteria (PGPR) strains can influence plant-insect interactions. However, little is known about the effect of changes in the soil bacterial community in general and especially the loss of rare soil microbes on these interactions. Here, the influence of rare soil microbe reduction on induced systemic resistance (ISR) in a wild ecotype of Arabidopsis thaliana against the aphid Myzus persicae was investigated. To create a gradient of microbial abundances, soil was inoculated with a serial dilution of a microbial community and responses of Arabidopsis plants that originated from the same site as the soil microbes were tested. Plant biomass, transcription of genes involved in plant defences, and insect performance were measured. In addition, the effects of the PGPR strain Pseudomonas fluorescens SS101 on plant and insect performance were tested under the influence of the various soil dilution treatments. Plant biomass showed a hump-shaped relationship with soil microbial community dilution, independent of aphid or Pseudomonas treatments. Both aphid infestation and inoculation with Pseudomonas reduced plant biomass, and led to downregulation of PR1 (salicylic acid-responsive gene) and CYP79B3 (involved in synthesis of glucosinolates). Aphid performance and gene transcription were unaffected by soil dilution. Neither the loss of rare microbial species, as caused by soil dilution, nor Pseudomonas affect the resistance of A. thaliana against M. persicae. However, both Pseudomonas survival and plant biomass respond to rare species loss. Thus, loss of rare soil microbial species can have a significant impact on both above- and below-ground organisms. © The Author(s) 2018. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
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Foote, N E; Davis, T S; Crowder, D W; Bosque-Pérez, N A; Eigenbrode, S D
2017-06-01
In cereal cropping systems of the Pacific Northwestern United States (PNW), climate change is projected to increase the frequency of drought during summer months, which could increase water stress for crop plants. Yet, it remains uncertain how interactions between herbivore species are affected by drought stress. Here, interactions between two cereal aphids present in PNW cereal systems, Metopolophium festucae (Theobald) subsp. cerealium (a newly invasive species) and Rhopalosiphum padi L. (a naturalized species), were tested relative to wheat water stress. When aphids were confined in leaf cages on wheat, asymmetrical facilitation occurred; per capita fecundity of R. padi was increased by 46% when M. festucae cerealium was also present, compared to when only R. padi was present. Imposed water stress did not influence this interaction. When aphids were confined on whole wheat plants, asymmetrical competition occurred; cocolonization inhibited M. festucae cerealium population growth but did not affect R. padi population growth. Under conditions of plant water stress, however, the inhibitory effect of R. padi on M. festucae cerealium was not observed. We conclude that beneficial effects of cocolonization on R. padi are due to a localized plant response to M. festucae cerealium feeding, and that cocolonization of plants is likely to suppress M. festucae cerealium populations under ample water conditions, but not when plants are water stressed. This suggests that plant responses to water stress alter the outcome of competition between herbivore species, with implications for the structure of pest communities on wheat during periods of drought. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America.
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Responses to ammonium and nitrate additions by boreal plants and their natural enemies
Energy Technology Data Exchange (ETDEWEB)
Nordin, Annika [Umeaa Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-901 83 Umeaa (Sweden)]. E-mail: annika.nordin@genfys.slu.se; Strengbom, Joachim [Department of Ecology and Environmental Sciences, Umeaa University, SE-901 87 Umeaa (Sweden)]. E-mail: joachim.strengbom@ebc.uu.se; Ericson, Lars [Department of Ecology and Environmental Sciences, Umeaa University, SE-901 87 Umeaa (Sweden)]. E-mail: lars.ericson@eg.umu.se
2006-05-15
Separate effects of ammonium (NH{sub 4} {sup +}) and nitrate (NO{sub 3} {sup -}) on boreal forest understorey vegetation were investigated in an experiment where 12.5 and 50.0 kg nitrogen (N) ha{sup -1} year{sup -1} was added to 2 m{sup 2} sized plots during 4 years. The dwarf-shrubs dominating the plant community, Vaccinium myrtillus and V. vitis-idaea, took up little of the added N independent of the chemical form, and their growth did not respond to the N treatments. The grass Deschampsia flexuosa increased from the N additions and most so in response to NO{sub 3} {sup -}. Bryophytes took up predominately NH{sub 4} {sup +} and there was a negative correlation between moss N concentration and abundance. Plant pathogenic fungi increased from the N additions, but showed no differences in response to the two N forms. Because the relative contribution of NH{sub 4} {sup +} and NO{sub 3} {sup -} to the total N deposition on a regional scale can vary substantially, the N load a habitat can sustain without substantial changes in the biota should be set considering specific vegetation responses to the predominant N form in deposition. - Biota will respond to nitrogen deposition depending on the form of nitrogen.
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Plant protein and animal proteins: do they differentially affect cardiovascular disease risk?
Richter, Chesney K; Skulas-Ray, Ann C; Champagne, Catherine M; Kris-Etherton, Penny M
2015-11-01
Proteins from plant-based compared with animal-based food sources may have different effects on cardiovascular disease (CVD) risk factors. Numerous epidemiologic and intervention studies have evaluated their respective health benefits; however, it is difficult to isolate the role of plant or animal protein on CVD risk. This review evaluates the current evidence from observational and intervention studies, focusing on the specific protein-providing foods and populations studied. Dietary protein is derived from many food sources, and each provides a different composite of nonprotein compounds that can also affect CVD risk factors. Increasing the consumption of protein-rich foods also typically results in lower intakes of other nutrients, which may simultaneously influence outcomes. Given these complexities, blanket statements about plant or animal protein may be too general, and greater consideration of the specific protein food sources and the background diet is required. The potential mechanisms responsible for any specific effects of plant and animal protein are similarly multifaceted and include the amino acid content of particular foods, contributions from other nonprotein compounds provided concomitantly by the whole food, and interactions with the gut microbiome. Evidence to date is inconclusive, and additional studies are needed to further advance our understanding of the complexity of plant protein vs. animal protein comparisons. Nonetheless, current evidence supports the idea that CVD risk can be reduced by a dietary pattern that provides more plant sources of protein compared with the typical American diet and also includes animal-based protein foods that are unprocessed and low in saturated fat. © 2015 American Society for Nutrition.
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Factors Affecting Planting Depth and Standing of Rice Seedling in Parachute Rice Transplanting
Astika, I. W.; Subrata, I. D. M.; Pramuhadi, G.
2018-05-01
Parachute rice transplanting is a simple and practical rice transplanting method. It can be done manually or mechanically, with various possible designs of machines or tools. This research aimed at quantitatively formulating related factors to the planting depth and standing of rice seedling. Parachute seedlings of rice were grown at several sizes of parachute soil bulb sizes. The trays were specially designed with a 3D printer having bulb sizes 7, 8, 9, 10 mm in square sides and 15 mm depth. At seedling ages of 8-12 days after sowing the seedling bulbs were drops into puddled soil. Soil hardness was set at 3 levels of hardness, measured in hardness index using golf ball test. Angle of dropping was set at 3 levels: 0°, 30°and 45° from the vertical axis. The height of droppings was set at 100 cm, 75 cm, and 50 cm. The relationship between bulb size, height of dropping, soil hardness, dropping angle and planting depth was formulated with ANN. Most of input variables did not significantly affect the planting depth, except that hard soil significantly differs from mild soil and soft soil. The dropping also resulted in various positions of the planted seedlings: vertical standing, sloped, and falling. However, at any position of the planted seedlings, the seedlings would recover themselves into normally vertical position. With this result, the design of planting machinery, as well as the manual planting operation, can be made easier.
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Evaluating barriers to native seedling establishment in an invaded Hawaiian lowland wet forest
S. Cordell; R. Ostertag; B. Rowe; L. Sweinhart; L. Vasquez-Radonic; J. Michaud; T.C. Cole; J.R. Schulten
2009-01-01
Many tropical island forest ecosystems are dominated by non-native plant species and lack native species regeneration in the understorey. Comparison of replicated control and removal plots offers an opportunity to examine not only invasive species impacts but also the restoration potential of native species. In lowland Hawaiian wet forests little is known about native...
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Stable elements and radionuclides in shoreline alder stands at Olkiluoto in 2005
International Nuclear Information System (INIS)
Roivainen, P.
2006-08-01
In Finland, the final disposal of spent nuclear fuel from Finnish nuclear power plants is to take place in a repository, which will be built in Olkiluoto bedrock. According to the current plans, operation of the facility will start in 2020. Before this, a safety case has to be drawn up to substantiate the safety of the final disposal solution. The drawing up of the safety case also involves an assessment of impact on organisms other than human. Several radionuclides have a stable chemical analogue. Chemical analogues often display similar behaviour in the forest ecosystem. For this reason, information about radionuclides can also be obtained by studying stable elements. The purpose of this thesis was to study the migration of elements, radionuclides in particular, in the food webs of the Olkiluoto forest ecosystem. The objective was to produce concentration ratios between the various sub-components of the forest ecosystem. These ratios can be utilised in modelling. Three alder stands on the shores of Olkiluoto were used as monitoring plots. Littoral alder stands are an important biotope in terms of a recipient of the potential radionuclide contamination from the repository. Yet, research on littoral alder stands has so far been quite limited. From all the monitoring plots, a sample was taken of humus, mineral soil, understorey, plant roots and forest litter. Small mammals and earthworms were also to be caught from the monitoring plots, but no earthworms could be caught in any of the areas. All the collected samples were analysed for element concentrations using the ICP-AES method. Soil and plant samples were also analysed with a gamma spectrometer for activity concentrations of gamma active radionuclides. Activity concentrations of Cs-137 and K-40 could be determined in all soil and plant samples. The highest activity concentration of Cs-137 was found in humus, and the lowest in mineral soil. The activity concentration of K-40 was at its highest in mineral soil and
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da Costa, Fernanda Vieira; de Queiroz, Antônio César Medeiros; Maia, Maria Luiza Bicalho; Júnior, Ronaldo Reis; Fagundes, Marcilio
2016-06-01
Plants have limited resources to invest in reproduction, vegetative growth and defense against herbivorous. Trade-off in resources allocation promotes changes in plant traits that may affect higher trophic levels. In this study, we evaluated the trade-off effect between years of high and low fruiting on the investment of resources for growth and defense, and their indirect effects on herbivory in Copaifera langsdorffii. Our questions were: (i) does the resource investment on reproduction causes a depletion in vegetative growth as predicted by the Carbon/Nutrient Balance hypothesis (CNBH), resulting in more availability of resources to be allocated for defense?, (ii) does the variation in resource allocation for growth and defense between years of high and low fruiting leads to indirect changes in herbivory? Thirty-five trees located in a Cerrado area were monitored during 2008 (year of high fruiting) and 2009 (year of no fruiting) to evaluate the differential investment in vegetative traits (biomass, growth and number of ramifications), plant defense (tannin concentration and plant hypersensitivity) and herbivory (galling attack and folivory). According to our first question, we observed that in the fruiting year, woody biomass negatively affected tannin concentration, indicating that fruit production restricted the resources that could be invested both in growth as in defense. In the same way, we observed an inter-annual variation in herbivorous attack, and found that plants with higher leaf biomass and tannin concentration, experienced higher galling attack and hypersensitive reaction, regardless years. These findings suggested that plants’ resistance to herbivory is a good proxy of plant defense and an effective defense strategy for C. langsdorffii, besides the evidence of indirect responses of the third trophic level, as postulated by the second question. In summary, the supra-annual fruiting pattern promoted several changes on plant development
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Guzmán Q, J Antonio; Cordero, Roberto A
2016-07-01
Plant design refers to the construction of the plant body or its constituent parts in terms of form and function. Although neighbourhood structure is recognized as a factor that limits plant survival and species coexistence, its relative importance in plant design is not well understood. We conducted field research to analyse how the surrounding environment of neighbourhood structure and related effects on light availability are associated with changes in plant design in two understorey plants (Palicourea padifolia and Psychotria elata) within two successional stages of a cloud forest in Costa Rica. Features of plant neighbourhood physical structure and light availability, estimated using hemispherical photographs, were used as variables that reflect the surrounding environment. Measures of plant biomechanics, allometry, branching and plant slenderness were used as functional plant attributes that reflect plant design. We propose a framework using a partial least squares path model and used it to test this association. The multidimensional response of plant design of these species suggests that decreases in the height-based factor of safety and increases in mechanical load and developmental stability are influenced by increases in maximum height of neighbours and a distance-dependence interference index more than neighbourhood plant density or neighbour aggregation. Changes in plant branching and slenderness are associated positively with light availability and negatively with canopy cover. Although it has been proposed that plant design varies according to plant density and light availability, we found that neighbour size and distance-dependence interference are associated with changes in biomechanics, allometry and branching, and they must be considered as key factors that contribute to the adaptation and coexistence of these plants in this highly diverse forest community. © The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany
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Fundamental aspects affecting the return on investment from solar power plants
International Nuclear Information System (INIS)
Cintula, B.; Viglas, D.
2012-01-01
The article deals with fundamental parameters of solar cells-conversion efficiency of solar radiation into electricity and price of solar cells. These two aspects affect each other, so it is important to deal with both at once. In introduction are described the theoretical solutions about efficiency analysis. Furthermore the article is focused on a description of materials used in the photovoltaic cells. In addition, the article shows the price trend of photovoltaic cells for the last year. Finally, these two aspects are evaluated for return on investment in photovoltaic power plants. (Authors)
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Fischer, C.; Tischer, J.; Roscher, C.; Eisenhauer, N.; Ravenek, J.; Gleixner, G.; Attinger, S.; Jensen, B.; Kroon, de H.; Mommer, L.; Scheu, S.; Hildebrandt, A.
2015-01-01
Background and aims Soil hydraulic properties drive water distribution and availability in soil. There exists limited knowledge of how plant species diversity might influence soil hydraulic properties. Methods We quantified the change in infiltration capacity affected by soil structural variables
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Ecotoxicological assessments show sucralose and fluoxetine affect the aquatic plant, Lemna minor.
Amy-Sagers, Cherisse; Reinhardt, Keith; Larson, Danelle M
2017-04-01
Pharmaceuticals and personal care products (PPCP) are prevalent in aquatic systems, yet the fate and impacts on aquatic plants needs quantification for many compounds. We measured and detected sucralose (an artificial sweetener), fluoxetine (an antidepressant), and other PPCP in the Portneuf River in Idaho, USA, where Lemna minor (an aquatic plant in the environment and used in ecotoxicology studies) naturally occurs. Sucralose was hypothesized to negatively affect photosynthesis and growth of L. minor because sucralose is a chlorinated molecule that may be toxic or unusable for plant metabolism. A priori hypotheses were not created for fluoxetine due to lack of previous studies examining its impacts on plants. We conducted laboratory ecotoxicological assessments for a large range of concentrations of sucralose and fluoxetine on L. minor physiology and photosynthetic function. Frond green leaf area, root length, growth rate, photosynthetic capacity, and plant carbon isotopic composition (discrimination relative to a standard; δ 13 C) were measured among treatments ranging from 0 to 15000nmol/L-sucralose and 0-323nmol/L-fluoxetine. Contrary to our predictions, sucralose significantly increased green leaf area, photosynthetic capacity, and δ 13 C of L. minor at environmentally relevant concentrations. The increase of δ 13 C from sucralose amendments and an isotope-mixing model indicated substantial sucralose uptake and assimilation within the plant. Unlike humans who cannot break down and utilize sucralose, we documented that L. minor-a mixotrophic plant-can use sucralose as a sugar substitute to increase its green leaf area and photosynthetic capacity. Fluoxetine significantly decreased L. minor root growth, daily growth rate, and asexual reproduction at 323nmol/L-fluoxetine; however, ambiguity remains regarding the mechanisms responsible and the applicability of these extreme concentrations unprecedented in the natural environment. To our knowledge, this was the
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Osmolyte cooperation affects turgor dynamics in plants
Argiolas, Alfredo; Puleo, Gian Luigi; Sinibaldi, Edoardo; Mazzolai, Barbara
2016-07-01
Scientists have identified turgor-based actuation as a fundamental mechanism in plant movements. Plant cell turgor is generated by water influx due to the osmolyte concentration gradient through the cell wall and the plasma membrane behaving as an osmotic barrier. Previous studies have focused on turgor modulation with respect to potassium chloride (KCl) concentration changes, although KCl is not efficiently retained in the cell, and many other compounds, including L-glutamine (L-Gln) and D-glucose (D-Glc), are present in the cytosol. In fact, the contributions of other osmolytes to turgor dynamics remain to be elucidated. Here, we show the association of osmolytes and their consequent cooperative effects on the time-dependent turgor profile generated in a model cytosol consisting of KCl, D-Glc and L-Gln at experimentally measured plant motor/generic cell concentrations and at modified concentrations. We demonstrate the influence and association of the osmolytes using osmometry and NMR measurements. We also show, using a plant cell-inspired device we previously developed, that osmolyte complexes, rather than single osmolytes, permit to obtain higher turgor required by plant movements. We provide quantitative cues for deeper investigations of osmolyte transport for plant movement, and reveal the possibility of developing osmotic actuators exploiting a dynamically varying concentration of osmolytes.
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Tea [Camellia sinensis (L.) O. Kuntze] is an important economic crop, and drought is the most important abiotic stress affecting yield and quality. Abscisic acid (ABA) is an important phytohormone responsible for activating drought resistance. Increased understanding of ABA effects on tea plant unde...
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Vargas-Zapata, Rigoberto; Torres-González, Vladimira; Sepúlveda-Saavedra, Julio; Piñeyro-López, Alfredo; Rechinger, Karl B.; Keizer-Gunnink, Ineke; Kiel, Jan A.K.W.; Veenhuis, Marten
Previously we demonstrated that peroxisomicine A1 (T-514), a plant toxin isolated from Karwinskia species, has a deteriorating effect on the integrity of peroxisomes of methylotrophic yeasts. Here we describe two strains of Hansenula polymorpha, affected in the normal utilization of methanol as sole
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Kegge, Wouter; Ninkovic, Velemir; Glinwood, Robert; Welschen, Rob A M; Voesenek, Laurentius A C J; Pierik, Ronald
2015-05-01
Volatile organic compounds (VOCs) play various roles in plant-plant interactions, and constitutively produced VOCs might act as a cue to sense neighbouring plants. Previous studies have shown that VOCs emitted from the barley (Hordeum vulgare) cultivar 'Alva' cause changes in biomass allocation in plants of the cultivar 'Kara'. Other studies have shown that shading and the low red:far-red (R:FR) conditions that prevail at high plant densities can reduce the quantity and alter the composition of the VOCs emitted by Arabidopsis thaliana, but whether this affects plant-plant signalling remains unknown. This study therefore examines the effects of far-red light enrichment on VOC emissions and plant-plant signalling between 'Alva' and 'Kara'. The proximity of neighbouring plants was mimicked by supplemental far-red light treatment of VOC emitter plants of barley grown in growth chambers. Volatiles emitted by 'Alva' under control and far-red light-enriched conditions were analysed using gas chromatography-mass spectrometry (GC-MS). 'Kara' plants were exposed to the VOC blend emitted by the 'Alva' plants that were subjected to either of the light treatments. Dry matter partitioning, leaf area, stem and total root length were determined for 'Kara' plants exposed to 'Alva' VOCs, and also for 'Alva' plants exposed to either control or far-red-enriched light treatments. Total VOC emissions by 'Alva' were reduced under low R:FR conditions compared with control light conditions, although individual volatile compounds were found to be either suppressed, induced or not affected by R:FR. The altered composition of the VOC blend emitted by 'Alva' plants exposed to low R:FR was found to affect carbon allocation in receiver plants of 'Kara'. The results indicate that changes in R:FR light conditions influence the emissions of VOCs in barley, and that these altered emissions affect VOC-mediated plant-plant interactions. © The Author 2015. Published by Oxford University Press on
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Carbon storage potential by four macrophytes as affected by planting diversity in a created wetland.
Means, Mary M; Ahn, Changwoo; Korol, Alicia R; Williams, Lisa D
2016-01-01
Wetland creation has become a commonplace method for mitigating the loss of natural wetlands. Often mitigation projects fail to restore ecosystem services of the impacted natural wetlands. One of the key ecosystem services of newly created wetlands is carbon accumulation/sequestration, but little is known about how planting diversity (PD) affects the ability of herbaceous wetland plants to store carbon in newly created wetlands. Most mitigation projects involve a planting regime, but PD, which may be critical in establishing biologically diverse and ecologically functioning wetlands, is seldom required. Using a set of 34 mesocosms (∼1 m(2) each), we investigated the effects of planting diversity on carbon storage potential of four native wetland plant species that are commonly planted in created mitigation wetlands in Virginia - Carex vulpinoidea, Eleocharis obtusa, Juncus effusus, and Mimulus ringens. The plants were grown under the four distinctive PD treatments [i.e., monoculture (PD 1) through four different species mixture (PD 4)]. Plant biomass was harvested after two growing seasons and analyzed for tissue carbon content. Competition values (CV) were calculated to understand how the PD treatment affected the competitive ability of plants relative to their biomass production and thus carbon storage potentials. Aboveground biomass ranged from 988 g/m(2) - 1515 g/m(2), being greatest in monocultures, but only when compared to the most diverse mixture (p = 0.021). However, carbon storage potential estimates per mesocosm ranged between 344 g C/m(2) in the most diverse mesocosms (PD 4) to 610 g C/m(2) in monoculture ones with no significant difference (p = 0.089). CV of E. obtusa and C. vulpinoidea showed a declining trend when grown in the most diverse mixtures but J. effusus and M. ringens displayed no difference across the PD gradient (p = 0.910). In monocultures, both M. ringens, and J. effusus appeared to store carbon as biomass more
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Ozone Differentially Affects Perception of Plant Volatiles in Western Honey Bees.
Dötterl, Stefan; Vater, Marina; Rupp, Thomas; Held, Andreas
2016-06-01
Floral scents play a key role in mediating plant-pollinator interactions. Volatile organic compounds (VOCs) emitted by flowers are used by flower visitors as olfactory cues to locate flowers, both from a distance and at close range. More recently it has been demonstrated that reactive molecules such as ozone can modify or degrade VOCs, and this may impair the communication between plants and their pollinators. However, it is not known whether such reactive molecules also may affect the olfactory system of pollinators, and thus not only influence signal transmission but perception of the signal. In this study, we used electroantennographic measurements to determine the effect of increased levels of ozone on antennal responses in western honey bees (Apis mellifera L.). Linalool and 2-phenylethanol, both known to be involved in location of flowers by the bees, and (Z)-3-hexenyl acetate, a widespread green leaf volatile also detected by bees, were used. The results showed that ozone affected antennal responses to the different substances differently. Ozone decreased antennal responses to (Z)-3-hexenyl acetate, whereas responses to linalool and 2-phenylethanol were not influenced by ozone. Overall, the study does not provide evidence that pollination by honey bees is impaired by damage in the olfactory system of the bees caused by increased levels of ozone, at least when linalool and 2-phenylethanol are the attractive signals. However, the results also suggest that ozone can change the overall perception of an odor blend. This might have negative effects in pollination systems and other organismic interactions mediated by specific ratios of compounds.
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International Nuclear Information System (INIS)
Roivainen, Paeivi; Makkonen, Sari; Holopainen, Toini; Juutilainen, Jukka
2012-01-01
Cobalt (Co), lead (Pb), molybdenum (Mo), nickel (Ni), uranium (U), and zinc (Zn) are among the elements that have radioactive isotopes in radioactive waste. Soil-to-plant transfer is a key process for possible adverse effects if these radionuclides are accidentally released into the environment. The present study aimed at investigating factors affecting such transfer in boreal forest. The plant species studied were blueberry (Vaccinium myrtillus), May lily (Maianthemum bifolium), narrow buckler fern (Dryopteris carthusiana), rowan (Sorbus aucuparia) and Norway spruce (Picea abies). Regression analyses were carried out to investigate the effects of the chemical composition and physical properties of soil on the soil-to-leaf/needle concentration ratios of Co, Mo, Ni, Pb, U and Zn. Soil potassium (K), magnesium (Mg), manganese (Mn), phosphorus (P) and sulphur (S) concentrations were the most important factors affecting the soil-to-plant transfer of the elements studied. Soil clay and organic matter contents were found to significantly affect plant uptake of Mo, Pb and U. Knowledge of the effects of these factors is helpful for interpretation of the predictions of radioecological models describing soil-to-plant transfer and for improving such models. (orig.)
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Energy Technology Data Exchange (ETDEWEB)
Roivainen, Paeivi; Makkonen, Sari; Holopainen, Toini; Juutilainen, Jukka [University of Eastern Finland, Department of Environmental Science, Kuopio (Finland)
2012-03-15
Cobalt (Co), lead (Pb), molybdenum (Mo), nickel (Ni), uranium (U), and zinc (Zn) are among the elements that have radioactive isotopes in radioactive waste. Soil-to-plant transfer is a key process for possible adverse effects if these radionuclides are accidentally released into the environment. The present study aimed at investigating factors affecting such transfer in boreal forest. The plant species studied were blueberry (Vaccinium myrtillus), May lily (Maianthemum bifolium), narrow buckler fern (Dryopteris carthusiana), rowan (Sorbus aucuparia) and Norway spruce (Picea abies). Regression analyses were carried out to investigate the effects of the chemical composition and physical properties of soil on the soil-to-leaf/needle concentration ratios of Co, Mo, Ni, Pb, U and Zn. Soil potassium (K), magnesium (Mg), manganese (Mn), phosphorus (P) and sulphur (S) concentrations were the most important factors affecting the soil-to-plant transfer of the elements studied. Soil clay and organic matter contents were found to significantly affect plant uptake of Mo, Pb and U. Knowledge of the effects of these factors is helpful for interpretation of the predictions of radioecological models describing soil-to-plant transfer and for improving such models. (orig.)
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Analysis of chemical factors affecting marine ecosystem around nuclear power plant
International Nuclear Information System (INIS)
Chun, Kwan Sik; Choi, Yoon Dong; Chun, Ki Jeong; Kim, Jin Kyu; Jung, Kyeong Chai; Lee, Yeong Keun; Park, Hyo Kook
1994-06-01
The ecological data of the coastal area of Youngkwang nuclear power plant from 1987 to 1993 were comprehensively analyzed, and various physical and chemical properties of sea water and sediments were measured. Major factors affecting phytoplankton standing crops were suspended substances, nitrate, and silicate. The contents of iron, chromium, copper, and sulfur in sediments sampled from the discharge channel were slightly higher than those in the other areas. In order to qantify the chemical impacts on marine ecosystem, it is desirable that a systematic survey be made through the whole year cycle to assure the consistency and confidence of the related data. (Author)
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Kegge, Wouter; Ninkovic, Velemir; Glinwood, Robert; Welschen, Rob A. M.; Voesenek, Laurentius A. C. J.; Pierik, Ronald
2015-01-01
Background and Aims Volatile organic compounds (VOCs) play various roles in plant–plant interactions, and constitutively produced VOCs might act as a cue to sense neighbouring plants. Previous studies have shown that VOCs emitted from the barley (Hordeum vulgare) cultivar ‘Alva’ cause changes in biomass allocation in plants of the cultivar ‘Kara’. Other studies have shown that shading and the low red:far-red (R:FR) conditions that prevail at high plant densities can reduce the quantity and alter the composition of the VOCs emitted by Arabidopsis thaliana, but whether this affects plant–plant signalling remains unknown. This study therefore examines the effects of far-red light enrichment on VOC emissions and plant–plant signalling between ‘Alva’ and ‘Kara’. Methods The proximity of neighbouring plants was mimicked by supplemental far-red light treatment of VOC emitter plants of barley grown in growth chambers. Volatiles emitted by ‘Alva’ under control and far-red light-enriched conditions were analysed using gas chromatography–mass spectrometry (GC-MS). ‘Kara’ plants were exposed to the VOC blend emitted by the ‘Alva’ plants that were subjected to either of the light treatments. Dry matter partitioning, leaf area, stem and total root length were determined for ‘Kara’ plants exposed to ‘Alva’ VOCs, and also for ‘Alva’ plants exposed to either control or far-red-enriched light treatments. Key Results Total VOC emissions by ‘Alva’ were reduced under low R:FR conditions compared with control light conditions, although individual volatile compounds were found to be either suppressed, induced or not affected by R:FR. The altered composition of the VOC blend emitted by ‘Alva’ plants exposed to low R:FR was found to affect carbon allocation in receiver plants of ‘Kara’. Conclusions The results indicate that changes in R:FR light conditions influence the emissions of VOCs in barley, and that these altered emissions
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Ozone affects growth and development of Pieris brassicae on the wild host plant Brassica nigra
International Nuclear Information System (INIS)
Khaling, Eliezer; Papazian, Stefano; Poelman, Erik H.; Holopainen, Jarmo K.; Albrectsen, Benedicte R.; Blande, James D.
2015-01-01
When plants are exposed to ozone they exhibit changes in both primary and secondary metabolism, which may affect their interactions with herbivorous insects. Here we investigated the performance and preferences of the specialist herbivore Pieris brassicae on the wild plant Brassica nigra under elevated ozone conditions. The direct and indirect effects of ozone on the plant-herbivore system were studied. In both cases ozone exposure had a negative effect on P. brassicae development. However, in dual-choice tests larvae preferentially consumed plant material previously fumigated with the highest concentration tested, showing a lack of correlation between larval preference and performance on ozone exposed plants. Metabolomic analysis of leaf material subjected to combinations of ozone and herbivore-feeding, and focussing on known defence metabolites, indicated that P. brassicae behaviour and performance were associated with ozone-induced alterations to glucosinolate and phenolic pools. - Highlights: • We examined the effects of ozone on Pieris brassicae performance and preference. • We studied ozone and herbivore induced changes in the metabolome of Brassica nigra. • The performance of P. brassicae did not correlate with preference of ozonated plants. • Ozone and herbivore-feeding stress changes the phytochemical pools of B. nigra. - Ozone indirectly reduces herbivore performance, which is associated with change in phytochemical pools, but does not correlate with host plant preference
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Directory of Open Access Journals (Sweden)
Yi Feng
Full Text Available The light brown apple moth, Epiphyas postvittana is a key pest of wine grapes in Australia. Two parasitoids, Dolichogenidea tasmanica and Therophilus unimaculatus, attack the larval stage of this pest. D. tasmanica is dominant in vineyards, whereas T. unimaculatus is mainly active in native vegetation. We sought to understand why they differ in their use of habitats. Plants are a major component of habitats of parasitoids, and herbivore-infested plants influence parasitoid foraging efficiency by their architecture and emission of volatile chemicals. We investigated how different plant species infested by E. postvittana could affect the foraging success of the two parasitoid species in both laboratory and field experiments. Four common host-plant species were selected for this study. In paired-choice experiments to determine the innate foraging preferences for plants, both parasitoid species showed differences in innate search preferences among plant species. The plant preference of D. tasmanica was altered by oviposition experience with hosts that were feeding on other plant species. In a behavioral assay, the two parasitoid species allocated their times engaged in various types of behavior differently when foraging on different plant species. For both parasitoids, parasitism on Hardenbergia violacea was the highest of the four plant species. Significantly more larvae dropped from Myoporum insulare when attacked than from the other three host-plant species, which indicates that parasitism is also affected by interactions between plants and host insects. In vineyards, parasitism by D. tasmanica was significantly lower on M. insulare than on the other three host-plant species, but the parasitism rates were similar among the other three plant species. Our results indicate that plants play a role in the habitat preferences of these two parasitoid species by influencing their foraging behavior, and are likely to contribute to their distributions
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Planting Technique and Care of Stock Affect Survival of Planted Red Pine
John H. Cooley
1974-01-01
Careless planting was found to be the most important of several possible causes of excessive mortality of newly planted red pine. Distribution procedures and high shoot/root ratios were also implicated.
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Ecotoxicological assessments show sucralose and fluoxetine affect the aquatic plant, Lemna minor
Energy Technology Data Exchange (ETDEWEB)
Amy-Sagers, Cherisse; Reinhardt, Keith; Larson, Danelle M., E-mail: danellelarson77@gmail.com
2017-04-15
Highlights: • Sucralose increased leaf area and photosynthetic capacity of Lemna minor. • Sucralose increased δ {sup 13}C of Lemna, indicating substantial uptake and assimilation. • 100 μg/L-fluoxetine decreased Lemna minor growth and asexual reproduction. - Abstract: Pharmaceuticals and personal care products (PPCP) are prevalent in aquatic systems, yet the fate and impacts on aquatic plants needs quantification for many compounds. We measured and detected sucralose (an artificial sweetener), fluoxetine (an antidepressant), and other PPCP in the Portneuf River in Idaho, USA, where Lemna minor (an aquatic plant in the environment and used in ecotoxicology studies) naturally occurs. Sucralose was hypothesized to negatively affect photosynthesis and growth of L. minor because sucralose is a chlorinated molecule that may be toxic or unusable for plant metabolism. A priori hypotheses were not created for fluoxetine due to lack of previous studies examining its impacts on plants. We conducted laboratory ecotoxicological assessments for a large range of concentrations of sucralose and fluoxetine on L. minor physiology and photosynthetic function. Frond green leaf area, root length, growth rate, photosynthetic capacity, and plant carbon isotopic composition (discrimination relative to a standard; δ{sup 13}C) were measured among treatments ranging from 0 to 15000 nmol/L-sucralose and 0–323 nmol/L-fluoxetine. Contrary to our predictions, sucralose significantly increased green leaf area, photosynthetic capacity, and δ {sup 13}C of L. minor at environmentally relevant concentrations. The increase of δ {sup 13}C from sucralose amendments and an isotope-mixing model indicated substantial sucralose uptake and assimilation within the plant. Unlike humans who cannot break down and utilize sucralose, we documented that L. minor—a mixotrophic plant—can use sucralose as a sugar substitute to increase its green leaf area and photosynthetic capacity. Fluoxetine
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Ecotoxicological assessments show sucralose and fluoxetine affect the aquatic plant, Lemna minor
International Nuclear Information System (INIS)
Amy-Sagers, Cherisse; Reinhardt, Keith; Larson, Danelle M.
2017-01-01
Highlights: • Sucralose increased leaf area and photosynthetic capacity of Lemna minor. • Sucralose increased δ "1"3C of Lemna, indicating substantial uptake and assimilation. • 100 μg/L-fluoxetine decreased Lemna minor growth and asexual reproduction. - Abstract: Pharmaceuticals and personal care products (PPCP) are prevalent in aquatic systems, yet the fate and impacts on aquatic plants needs quantification for many compounds. We measured and detected sucralose (an artificial sweetener), fluoxetine (an antidepressant), and other PPCP in the Portneuf River in Idaho, USA, where Lemna minor (an aquatic plant in the environment and used in ecotoxicology studies) naturally occurs. Sucralose was hypothesized to negatively affect photosynthesis and growth of L. minor because sucralose is a chlorinated molecule that may be toxic or unusable for plant metabolism. A priori hypotheses were not created for fluoxetine due to lack of previous studies examining its impacts on plants. We conducted laboratory ecotoxicological assessments for a large range of concentrations of sucralose and fluoxetine on L. minor physiology and photosynthetic function. Frond green leaf area, root length, growth rate, photosynthetic capacity, and plant carbon isotopic composition (discrimination relative to a standard; δ"1"3C) were measured among treatments ranging from 0 to 15000 nmol/L-sucralose and 0–323 nmol/L-fluoxetine. Contrary to our predictions, sucralose significantly increased green leaf area, photosynthetic capacity, and δ "1"3C of L. minor at environmentally relevant concentrations. The increase of δ "1"3C from sucralose amendments and an isotope-mixing model indicated substantial sucralose uptake and assimilation within the plant. Unlike humans who cannot break down and utilize sucralose, we documented that L. minor—a mixotrophic plant—can use sucralose as a sugar substitute to increase its green leaf area and photosynthetic capacity. Fluoxetine significantly
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Li, Xiaoqiong; Guo, Wenfeng; Siemann, Evan; Wen, Yuanguang; Huang, Wei; Ding, Jianqing
2016-12-01
Spatially separated aboveground (AG) and belowground (BG) herbivores are closely linked through shared host plants, and both patterns of AG-BG interactions and plant responses may vary among plant genotypes. We subjected invasive (USA) and native (China) genotypes of tallow tree (Triadica sebifera) to herbivory by the AG specialist leaf-rolling weevil Heterapoderopsis bicallosicollis and/or the root-feeding larvae of flea beetle Bikasha collaris. We measured leaf damage and leaves rolled by weevils, quantified beetle survival, and analyzed flavonoid and tannin concentrations in leaves and roots. AG and BG herbivores formed negative feedbacks on both native and invasive genotypes. Leaf damage by weevils and the number of beetle larvae emerging as adults were higher on invasive genotypes. Beetles reduced weevil damage and weevils reduced beetle larval emergence more strongly for invasive genotypes. Invasive genotypes had lower leaf and root tannins than native genotypes. BG beetles decreased leaf tannins of native genotypes but increased root tannins of invasive genotypes. AG herbivory increased root flavonoids of invasive genotypes while BG herbivory decreased leaf flavonoids. Invasive genotypes had lower AG and BG herbivore resistance, and negative AG-BG herbivore feedbacks were much stronger for invasive genotypes. Lower tannin concentrations explained overall better AG and BG herbivore performances on invasive genotypes. However, changes in tannins and flavonoids affected AG and BG herbivores differently. These results suggest that divergent selection on chemical production in invasive plants may be critical in regulating herbivore performances and novel AG and BG herbivore communities in new environments.
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Tillage and planting density affect the performance of maize hybrids in Chitwan, Nepal
Directory of Open Access Journals (Sweden)
Tika Baladur Karki
2015-12-01
Full Text Available To find out whether the different tillage methods at different planting densities affect the performance of maize hybrids, an experiment was carried out at National Maize Research Program, Rampur during spring season of 2013 and 2014. The experiment was laid out in strip plot design with three replications having 12 treatments. The vertical factor was tillage with conservation tillage (No Tillage + residue=NT and conventional tillage (CT and the horizontal factor were genotypes (Rampur Hybrid-2 and RML-32/RML-17 and in split planting geometries (75cm × 25cm =53333 plants/ha, 70cm × 25cm=57142 plant/ha and 60cm ×25cm= 66666 plants/ha. In both the years, the highest number of cobs (73,177 and 67638/ha was recorded at planting density of 66666/ha. NT had the highest no of kernel rows/cob (14.01 as against 12.12 in CT in 2014. The highest number of kernels (27.3 and 29.29 per row was recorded in NT during 2013 and 2014 respectively. Similarly, in 2014, the highest number of kernels were found in RML-32/RMl-17 (29.17/row and planting density of 53333/ha (28.46/row. In 2013, RML-32/RML-17 produced the highest test weight of 363.94g over the Rampur hybrid-2 with 362.17g. Significantly the highest grain yield of 9240.00 kg/ha in 2013 and 7459.80 kg/ha in 2014 at planting geometry of 65cm ×25cm were recorded. No effects was found by tillage methods for grain yields of maize in 2013, but was found in 2014 (7012.18 kg in NT compared to 6037.59 kg/ha in CT. NT and wider spaced crop matured earlier in both the years; however Rampur hybrid-2 matured earlier to RML-32/RML-17 in 2013. In 2014, harvest index of 47.85 % was recorded in planting geometry of 66666/ha, the highest benefit cost ratio of 1.36 was worked out in NT and 1.46 at the density of 66666/ha. The highest value of 2.46% of soil organic matter was recorded in NT as compared to 2.43% in CT.
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Spectral quality affects disease development of three pathogens on hydroponically grown plants
Schuerger, A. C.; Brown, C. S.; Sager, J. C. (Principal Investigator)
1997-01-01
Plants were grown under light-emitting diode (LED) arrays with various spectra to determine the effects of light quality on the development of diseases caused by tomato mosaic virus (ToMV) on pepper (Capsicum annuum L.), powdery mildew [Sphaerotheca fuliginea (Schlectend:Fr.) Pollaci] on cucumber (Cucumis sativus L.), and bacterial wilt (Pseudomonas solanacearum Smith) on tomato (Lycopersicon esculentum Mill.). One LED (660) array supplied 99% red light at 660 nm (25 nm bandwidth at half-peak height) and 1% far-red light between 700 to 800 nm. A second LED (660/735) array supplied 83% red light at 660 nm and 17% far-red light at 735 nm (25 nm bandwidth at half-peak height). A third LED (660/BF) array supplied 98% red light at 660 nm, 1% blue light (BF) between 350 to 550 nm, and 1% far-red light between 700 to 800 nm. Control plants were grown under broad-spectrum metal halide (MH) lamps. Plants were grown at a mean photon flux (300 to 800 nm) of 330 micromoles m-2 s-1 under a 12-h day/night photoperiod. Spectral quality affected each pathosystem differently. In the ToMV/pepper pathosystem, disease symptoms developed slower and were less severe in plants grown under light sources that contained blue and UV-A wavelengths (MH and 660/BF treatments) compared to plants grown under light sources that lacked blue and UV-A wavelengths (660 and 660/735 LED arrays). In contrast, the number of colonies per leaf was highest and the mean colony diameters of S. fuliginea on cucumber plants were largest on leaves grown under the MH lamp (highest amount of blue and UV-A light) and least on leaves grown under the 660 LED array (no blue or UV-A light). The addition of far-red irradiation to the primary light source in the 660/735 LED array increased the colony counts per leaf in the S. fuliginea/cucumber pathosystem compared to the red-only (660) LED array. In the P. solanacearum/tomato pathosystem, disease symptoms were less severe in plants grown under the 660 LED array, but the
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Tsunoda, Tomonori; Kachi, Naoki; Suzuki, Jun-Ichirou
2014-01-01
We examined how the volume and temporal heterogeneity of water supply changed the vertical distribution and mortality of a belowground herbivore, and consequently affected plant biomass. Plantago lanceolata (Plantaginaceae) seedlings were grown at one per pot under different combinations of water volume (large or small volume) and heterogeneity (homogeneous water conditions, watered every day; heterogeneous conditions, watered every 4 days) in the presence or absence of a larva of the belowground herbivorous insect, Anomala cuprea (Coleoptera: Scarabaeidae). The larva was confined in different vertical distributions to top feeding zone (top treatment), middle feeding zone (middle treatment), or bottom feeding zone (bottom treatment); alternatively no larva was introduced (control treatment) or larval movement was not confined (free treatment). Three-way interaction between water volume, heterogeneity, and the herbivore significantly affected plant biomass. With a large water volume, plant biomass was lower in free treatment than in control treatment regardless of heterogeneity. Plant biomass in free treatment was as low as in top treatment. With a small water volume and in free treatment, plant biomass was low (similar to that under top treatment) under homogeneous water conditions but high under heterogeneous ones (similar to that under middle or bottom treatment). Therefore, there was little effect of belowground herbivory on plant growth under heterogeneous water conditions. In other watering regimes, herbivores would be distributed in the shallow soil and reduced root biomass. Herbivore mortality was high with homogeneous application of a large volume or heterogeneous application of a small water volume. Under the large water volume, plant biomass was high in pots in which the herbivore had died. Thus, the combinations of water volume and heterogeneity affected plant growth via the change of a belowground herbivore.
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International Nuclear Information System (INIS)
Ashraf, M.; Hasnain, S.; Berge, O.
2006-01-01
Effect of soil salinity on physico-chemical and biological properties renders the salt-affected soils unsuitable for soil microbial processes and growth of the crop plants. Soil aggregation around roots of the plants is a function of the bacterial exo-polysaccharides, however, such a role of the EPS-producing bacteria in the saline environments has rarely been investigated. Pot experiments were conducted to observe the effects of inoculating six strains of exo-polysaccharides-producing bacteria on growth of primary (seminal) roots and its relationship with saccharides, cations (Ca 2+, Na +, K +) contents and mass of rhizosheath soils of roots of the wheat plants grown in a salt-affected soil. A strong positive relationship of RS with different root growth parameters indicated that an integrated influence of various biotic and abiotic RS factors would have controlled and promoted growth of roots of the inoculated wheat plants. The increase in root growth in turn could help inoculated wheat plants to withstand the negative effects of soil salinity through an enhanced soil water uptake, a restricted Na +i nflux in the plants and the accelerated soil microbial process involved in cycling and availability of the soil nutrients to the plants. It was concluded that inoculation of the exo- polysaccharides producing would be a valuable tool for amelioration and increasing crop productivity of the salt-affected soils
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AQUATIC PLANT SPECIATION AFFECTED BY DIVERSIFYING SELECTION OF ORGANELLE DNA REGIONS(1).
Kato, Syou; Misawa, Kazuharu; Takahashi, Fumio; Sakayama, Hidetoshi; Sano, Satomi; Kosuge, Keiko; Kasai, Fumie; Watanabe, Makoto M; Tanaka, Jiro; Nozaki, Hisayoshi
2011-10-01
Many of the genes that control photosynthesis are carried in the chloroplast. These genes differ among species. However, evidence has yet to be reported revealing the involvement of organelle genes in the initial stages of plant speciation. To elucidate the molecular basis of aquatic plant speciation, we focused on the unique plant species Chara braunii C. C. Gmel. that inhabits both shallow and deep freshwater habitats and exhibits habitat-based dimorphism of chloroplast DNA (cpDNA). Here, we examined the "shallow" and "deep" subpopulations of C. braunii using two nuclear DNA (nDNA) markers and cpDNA. Genetic differentiation between the two subpopulations was measured in both nDNA and cpDNA regions, although phylogenetic analyses suggested nuclear gene flow between subpopulations. Neutrality tests based on Tajima's D demonstrated diversifying selection acting on organelle DNA regions. Furthermore, both "shallow" and "deep" haplotypes of cpDNA detected in cultures originating from bottom soils of three deep environments suggested that migration of oospores (dormant zygotes) between the two habitats occurs irrespective of the complete habitat-based dimorphism of cpDNA from field-collected vegetative thalli. Therefore, the two subpopulations are highly selected by their different aquatic habitats and show prezygotic isolation, which represents an initial process of speciation affected by ecologically based divergent selection of organelle genes. © 2011 Phycological Society of America.
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Rostás, Michael; Cripps, Michael G; Silcock, Patrick
2015-02-01
Plants emit specific blends of volatile organic compounds (VOCs) that serve as multitrophic, multifunctional signals. Fungi colonizing aboveground (AG) or belowground (BG) plant structures can modify VOC patterns, thereby altering the information content for AG insects. Whether AG microbes affect the emission of root volatiles and thus influence soil insect behaviour is unknown. The endophytic fungus Neotyphodium uncinatum colonizes the aerial parts of the grass hybrid Festuca pratensis × Lolium perenne and is responsible for the presence of insect-toxic loline alkaloids in shoots and roots. We investigated whether endophyte symbiosis had an effect on the volatile emission of grass roots and if the root herbivore Costelytra zealandica was able to recognize endophyte-infected plants by olfaction. In BG olfactometer assays, larvae of C. zealandica were more strongly attracted to roots of uninfected than endophyte-harbouring grasses. Combined gas chromatography-mass spectrometry and proton transfer reaction-mass spectrometry revealed that endophyte-infected roots emitted less VOCs and more CO2. Our results demonstrate that symbiotic fungi in plants may influence soil insect distribution by changing their behaviour towards root volatiles. The well-known defensive mutualism between grasses and Neotyphodium endophytes could thus go beyond bioactive alkaloids and also confer protection by being chemically less apparent for soil herbivores.
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Does overhead irrigation with salt affect growth, yield, and phenolic content of lentil plants?
Directory of Open Access Journals (Sweden)
Giannakoula Anastasia
2012-01-01
Full Text Available Overhead irrigation of lentil plants with salt (100 mM NaCl did not have any significant impact on plant growth, while chlorophyll content and chlorophyll fluorescence parameter Fv/Fm were affected. Under such poor irrigation water quality, the malondialdehyde content in leaves was increased due to the lipid peroxidation of membranes. In seeds, the total phenolic content (TPC was correlated to their total antioxidant capacity (TAC. High performance liquid chromatography-mass spectrometry (HPLC-MS detection showed that flavonoids (catechin, epicatechin, rutin, p-coumaric acid, quercetin, kaempferol, gallic acid and resveratrol appear to be the compounds with the greatest influence on the TAC values. Catechin is the most abundant phenolic compound in lentil seeds. Overhead irrigation with salt reduced the concentration of almost all phenolic compounds analyzed from lentil seed extracts.
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Affective imagery and acceptance of replacing nuclear power plants.
Keller, Carmen; Visschers, Vivianne; Siegrist, Michael
2012-03-01
This study examined the relationship between the content of spontaneous associations with nuclear power plants and the acceptance of using new-generation nuclear power plants to replace old ones. The study also considered gender as a variable. A representative sample of the German- and French-speaking population of Switzerland (N= 1,221) was used. Log-linear models revealed significant two-way interactions between the association content and acceptance, association content and gender, and gender and acceptance. Correspondence analysis revealed that participants who were opposed to nuclear power plants mainly associated nuclear power plants with risk, negative feelings, accidents, radioactivity, waste disposal, military use, and negative consequences for health and environment; whereas participants favoring nuclear power plants mainly associated them with energy, appearance descriptions of nuclear power plants, and necessity. Thus, individuals opposing nuclear power plants had both more concrete and more diverse associations with them than people who were in favor of nuclear power plants. In addition, participants who were undecided often mentioned similar associations to those participants who were in favor. Males more often expressed associations with energy, waste disposal, and negative health effects. Females more often made associations with appearance descriptions, negative feelings, and negative environmental effects. The results further suggest that acceptance of replacing nuclear power plants was higher in the German-speaking part of the country, where all of the Swiss nuclear power plants are physically located. Practical implications for risk communication are discussed. © 2011 Society for Risk Analysis.
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Radionuclides and heavy metal uptake by lolium italicum plant as affected by saline water irrigation
International Nuclear Information System (INIS)
Ramadan, A.A.; Aly, A.I.; Helal, M.H.
2001-01-01
The use of saline waters to grow crops on increasingly metal polluted soils is becoming a common practice in the arid regions. Nevertheless, the effects of soil and water salinity on radionuclides and heavy metal fluxes in polluted areas are not well understood. The aim of this study was to evaluate in pot experiments the plant uptake of cesium-137, Co-60, Mn-54, Zinc, cadmium and copper from a polluted alluvial aridisol as affected by salt water irrigation. Fertilized soil material was planted in pots with L. Italicum for 18 weeks under greenhouse conditions. The plants were irrigated either with water or with salt solution of variable variable Na/Ca ratio and harvested every 5-7 weeks. In addition to elemental analysis of plants and soil extracts root length was determined by a gridline intersect method and the viable part of the roots was estimated by a root protein inex. Saline (Na) water irrigation increased cobalt-60, manganese-54 and heavy metal solubility in soil, reduced root viability and enhanced the uptake of Co-60, Mn-54, Cd, Cu, Zn and Na by L.italicum and reduced the uptake of Cs-137. Ca counteracted these effects partly. The presented results demonstrated a dual effect of salinity on radiouclides and heavy metal availability to plants and suggest a relationship between root mortality and the enhanced Co-60, Mn-54, and heavy metake ny salt stressed plants
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Directory of Open Access Journals (Sweden)
Kimura Shinzo
2006-01-01
Full Text Available This paper describes the use of a photostimulable phosphor screen imaging technique to detect radioactive contamination in the leaves of wormwood (Artemisia vulgaris L and fern (Dryopteris filix-max CL. Schoff plants affected by the Chernobyl nuclear power plant accident. The imaging plate technology is well known for many striking performances in two-dimensional radiation detection. Since imaging plate comprises an integrated detection system, it has been extensively applied to surface contamination distribution studies. In this study, plant samples were collected from high- and low-contaminated areas of Ukraine and Belarus, which were affected due to the Chernobyl accident and exposed to imaging technique. Samples from the highly contaminated areas revealed the highest photo-stimulated luminescence on the imaging plate. Moreover, the radio nuclides detected in the leaves by gamma and beta ray spectroscopy were 137Cs and 90Sr, respectively. Additionally, in order to assess contamination, a comparison was also made with leaves of plants affected during the JCO criticality accident in Japan. Based on the results obtained, the importance of imaging plate technology in environmental radiation monitoring has been suggested.
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International Nuclear Information System (INIS)
Lux, D.; Kammerer, L.; Simko, M.; Hiersche, L.; Wirth, E.
1993-01-01
In the framework of the C.E.C. research project ECP-5 entitled ''The behaviour of radionuclides in natural and semi-natural ecosystems'' our institute carried out investigations on selected sites of forest ecosystems in the 30-km-zone of Chernobyl in cooperation with research instituts of the C.I.S. states Russia and Ukraine. Our research is concentrated on the transfer of radionuclides from soil to plants of the understorey, especially species of farns and berries, as this plants take up their nutrients mainly from the upper organic horizons. (orig.) [de
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International Nuclear Information System (INIS)
ABOU-ELKHAIR, R.A.; EL-MOHTASEM, M.O.; SOLIMAN, S.M.; GALAL, Y.G.M.; ABD EL-LATIF, E.M.
2009-01-01
A pot experiment was conducted in the green house of Soil and Water Department, Nuclear Research Centre, Atomic Energy Authority, Egypt, to follow up the effect of saline irrigation water, inorganic and organic fertilizers on sorghum growth and N fractions that recovered by plant organs. Two types of artificial water salinity were used; one has 3 dS m -1 salinity level with 4 and 8 SAR and the second one has 3 and 6 dS m -1 salinity levels with 6 SAR . Leucenae residue and chicken manure were applied as organic sources at rate of 2% v/v. Sorghum was fertilized with recommended doses of super phosphate and potassium sulfate at rate of 150 kg P and 50 kg K per feddan, respectively. Labelled ammonium sulfate with 5% 15 N atom excess was applied to sorghum at rate of 100 kg N fed -1 . Dry matter yield (stalks and roots) was negatively affected by increasing water salinity levels or SAR ratios. Similar trend was recorded with N uptake by either stalks or roots of sorghum plants. On the other hand, both the dry matter yield and N uptake were positively and significantly affected by incorporation of organic sources in comparison to the untreated control. In this regard, the dry matter yield and N uptake induced by incorporation of chicken manure was superior over those recorded with leucenae residues. It means, in general, that the incorporation of organic sources into the soil may maximize the plant ability to combat the hazards effects caused by irrigation with saline water. Nitrogen derived from fertilizer (% Ndff), soil (% Ndfs) and organic resources (% Ndfr) showed frequent trends as affected by water salinity and organic resources but in most cases, severe reduction of these values was recorded when plants were irrigated with saline water. In the same time, plants were more dependent on N derived from organic sources than those derived from mineral fertilizer. Superiority of one organic source over the other was related to water salinity levels and SAR ratios
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Nieto-Jacobo, Maria F.; Steyaert, Johanna M.; Salazar-Badillo, Fatima B.; Nguyen, Dianne Vi; Rostás, Michael; Braithwaite, Mark; De Souza, Jorge T.; Jimenez-Bremont, Juan F.; Ohkura, Mana; Stewart, Alison
2017-01-01
Trichoderma species are soil-borne filamentous fungi widely utilized for their many plant health benefits, such as conferring improved growth, disease resistance and abiotic stress tolerance to their hosts. Many Trichoderma species are able to produce the auxin phytohormone indole-3-acetic acid (IAA), and its production has been suggested to promote root growth. Here we show that the production of IAA is strain dependent and diverse external stimuli are associated with its production. In in vitro assays, Arabidopsis primary root length was negatively affected by the interaction with some Trichoderma strains. In soil experiments, a continuum effect on plant growth was shown and this was also strain dependent. In plate assays, some strains of Trichoderma spp. inhibited the expression of the auxin reporter gene DR5 in Arabidopsis primary roots but not secondary roots. When Trichoderma spp. and A. thaliana were physically separated, enhancement of both shoot and root biomass, increased root production and chlorophyll content were observed, which strongly suggested that volatile production by the fungus influenced the parameters analyzed. Trichoderma strains T. virens Gv29.8, T. atroviride IMI206040, T. sp. “atroviride B” LU132, and T. asperellum LU1370 were demonstrated to promote plant growth through volatile production. However, contrasting differences were observed with LU1370 which had a negative effect on plant growth in soil but a positive effect in plate assays. Altogether our results suggest that the mechanisms and molecules involved in plant growth promotion by Trichoderma spp. are multivariable and are affected by the environmental conditions. PMID:28232840
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Wang, Xianzhong; Taub, Daniel R; Jablonski, Leanne M
2015-04-01
Reproduction is an important life history trait that strongly affects dynamics of plant populations. Although it has been well documented that elevated carbon dioxide (CO2) in the atmosphere greatly enhances biomass production in plants, the overall effect of elevated CO2 on reproductive allocation (RA), i.e., the proportion of biomass allocated to reproductive structures, is little understood. We combined meta-analysis with graphical vector analysis to examine the overall effect of elevated CO2 on RA and how other environmental factors, such as low nutrients, drought and elevated atmospheric ozone (O3), interacted with elevated CO2 in affecting RA in herbaceous plants. Averaged across all species of different functional groups and environmental conditions, elevated CO2 had little effect on RA (-0.9%). RA in plants of different reproductive strategies and functional groups, however, differed in response to elevated CO2. For example, RA in iteroparous wild species decreased by 8%, while RA in iteroparous crops increased significantly (+14%) at elevated CO2. RA was unaffected by CO2 in plants grown with no stress or in low-nutrient soils. RA decreased at elevated CO2 and elevated O3, but increased in response to elevated CO2 in drought-stressed plants, suggesting that elevated CO2 could ameliorate the adverse effect of drought on crop production to some extent. Our results demonstrate that elevated CO2 and other global environmental changes have the potential to greatly alter plant community composition through differential effects on RA of different plant species and thus affect the dynamics of natural and agricultural ecosystems in the future.
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Desurmont, Gaylord A; Zemanova, Miriam A; Turlings, Ted C J
2016-03-01
Terrestrial molluscs and insect herbivores play a major role as plant consumers in a number of ecosystems, but their direct and indirect interactions have hardly been explored. The omnivorous nature of slugs makes them potential disrupters of predator-prey relationships, as a direct threat to small insects and through indirect, plant-mediated effects. Here, we examined the effects of the presence of two species of slugs, Arion rufus (native) and A. vulgaris (invasive) on the survivorship of young Pieris brassicae caterpillars when feeding on Brassica rapa plants, and on plant attractiveness to the main natural enemy of P. brassicae, the parasitoid Cotesia glomerata. In two separate predation experiments, caterpillar mortality was significantly higher on plants co-infested with A. rufus or A. vulgaris. Moreover, caterpillar mortality correlated positively with slug mass and leaf consumption by A. vulgaris. At the third trophic level, plants infested with slugs and plants co-infested with slugs and caterpillars were far less attractive to parasitoids than plants damaged by caterpillars only, independently of slug species. Chemical analyses confirmed that volatile emissions, which provide foraging cues for parasitoids, were strongly reduced in co-infested plants. Our study shows that the presence of slugs has the potential to affect insect populations, directly via consumptive effects, and indirectly via changes in plant volatiles that result in a reduced attraction of natural enemies. The fitness cost for P. brassicae imposed by increased mortality in presence of slugs may be counterbalanced by the benefit of escaping its parasitoids.
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Temporal changes affect plant chemistry and tritrophic interactions
Gols, R.; Raaijmakers, C.E.; Van Dam, N.M.; Dicke, M.; Bukovinszky, T.; Harvey, J.A.
2007-01-01
In nature, individuals of short-lived plant species (e.g. annuals, biennials) may grow at different times during the growing season. These plants are therefore exposed to different season-related conditions such as light and temperature, which in turn may have consequences for primary and secondary
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Vertical stratification of bat assemblages in flooded and unflooded Amazonian forests
Directory of Open Access Journals (Sweden)
Maria João Ramos PEREIRA, João Tiago MARQUES, Jorge M. PALMEIRIM
2010-08-01
Full Text Available Tropical rainforests usually have multiple strata that results in a vertical stratification of ecological opportunities for animals. We investigated if this stratification influences the way bats use the vertical space in flooded and unflooded forests of the Central Amazon. Using mist-nets set in the canopy (17 to 35 m high and in the understorey (0 to 3 m high we sampled four sites in upland unflooded forests (terra firme, three in forests seasonally flooded by nutrient-rich water (várzea, and three in forests seasonally flooded by nutrient-poor water (igapó. Using rarefaction curves we found that species richness in the understorey and canopy were very similar. An ordination analysis clearly separated the bat assemblages of the canopy from those of the understorey in both flooded and unflooded habitats. Gleaning carnivores were clearly associated with the understorey, whereas frugivores were abundant in both strata. Of the frugivores, Carollinae and some Stenodermatinae were understorey specialists, but several Stenodermatinae mostly used the canopy. The first group mainly includes species that, in general, feed on fruits of understorey shrubs, whereas the second group feed on figs and other canopy fruits. We conclude that vertical stratification in bat communities occurs even within forests with lower canopy heights, such as Amazonian seasonally flooded forests, and that the vertical distribution of bat species is closely related to their diet and foraging behaviour [Current Zoology 56 (4: 469–478, 2010].
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Savage, Jessica A; Clearwater, Michael J; Haines, Dustin F; Klein, Tamir; Mencuccini, Maurizio; Sevanto, Sanna; Turgeon, Robert; Zhang, Cankui
2016-04-01
Despite the crucial role of carbon transport in whole plant physiology and its impact on plant-environment interactions and ecosystem function, relatively little research has tried to examine how phloem physiology impacts plant ecology. In this review, we highlight several areas of active research where inquiry into phloem physiology has increased our understanding of whole plant function and ecological processes. We consider how xylem-phloem interactions impact plant drought tolerance and reproduction, how phloem transport influences carbon allocation in trees and carbon cycling in ecosystems and how phloem function mediates plant relations with insects, pests, microbes and symbiotes. We argue that in spite of challenges that exist in studying phloem physiology, it is critical that we consider the role of this dynamic vascular system when examining the relationship between plants and their biotic and abiotic environment. © 2015 John Wiley & Sons Ltd.
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Siecińska, Joanna; Nosalewicz, Artur
Aluminium toxicity to crops depends on the acidity of the soil and specific plant resistance. However, it is also strongly affected by other environmental factors that have to be considered to properly evaluate the resultant effects on plants. Observed weather perturbations and predicted climate changes will increase the probability of co-occurrence of aluminium toxicity and other abiotic stresses.In this review the mechanisms of plant-aluminium interactions are shown to be influenced by soil mineral nutrients, heavy metals, organic matter, oxidative stress and drought. Described effects of aluminium toxicity include: root growth inhibition, reduction in the uptake of mineral nutrients resulting from the inhibition of transport processes through ion channels; epigenetic changes to DNA resulting in gene silencing. Complex processes occurring in the rhizosphere are highlighted, including the role of soil organic matter and aluminium detoxification by mucilage.There is a considerable research gap in the understanding of root growth in the soil environment in the presence of toxic aluminium concentrations as affected by interactions with abiotic stressors. This knowledge is important for the selection of feasible methods aimed at the reduction of negative consequences of crop production in acidic soils affected by adverse growth environment.
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Souza, Danielle G; Santos, Jean C; Oliveira, Marcondes A; Tabarelli, Marcelo
2016-10-01
Impacts of habitat loss and fragmentation on specialist herbivores have been rarely addressed. Here we examine the structure of plant and galling insect assemblages in a fragmented landscape of the Atlantic forest to verify a potential impoverishment of these assemblages mediated by edge effects. Saplings and galling insects were recorded once within a 0.1-ha area at habitat level, covering forest interior stands, forest edges, and small fragments. A total of 1,769 saplings from 219 tree species were recorded across all three habitats, with differences in terms of sapling abundance and species richness. Additionally, edge-affected habitats exhibited reduced richness of both host-plant and galling insects at plot and habitat spatial scale. Attack levels also differed among forest types at habitat spatial scale (21.1% of attacked stems in forest interior, 12.4% in small fragments but only 8.5% in forest edges). Plot ordination resulted in three clearly segregated clusters: one formed by forest interior, one by small fragments, and another formed by edge plots. Finally, the indicator species analysis identified seven and one indicator plant species in forest interior and edge-affected habitats, respectively. Consequently, edge effects lead to formation of distinct taxonomic groups and also an impoverished assemblage of plants and galling insects at multiple spatial scales. The results of the present study indicate that fragmentation-related changes in plant assemblages can have a cascade effects on specialist herbivores. Accordingly, hyperfragmented landscapes may not be able to retain an expressive portion of tropical biodiversity. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
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Gaume, L.; McKey, D.; Terrin, S.
1998-01-01
By estimating relative costs and benefits, we explored the role of the homopteran partner in the protection mutualism between the myrmecophyte Leonardoxa africana T3, the ant Aphomomyrmex afer, and sap-sucking homopterans tended by ants in the tree's swollen hollow twigs. The ants obtain nest sites and food from their host-plant (food is obtained either directly by extrafloral nectar or indirectly via homopterans). Aphomomyrmex workers patrol the young leaves of L. africana T3 and protect them against phytophagous insects. Because ants tended, either solely or primarily, coccids in some trees and pseudococcids in others, we were able to study whether the nature of the interaction was dependent on the identity of the third partner. First, the type of homopteran affects the benefits to the tree of maintaining a large ant colony. Larger colony size (relative to tree size) confers greater protection against herbivory; this relationship is more pronounced for trees whose ants tend pseudococcids than for those in which ants tend coccids. Second, for trees (and associated ant colonies) of comparable size, homopteran biomass was much larger in trees harbouring coccids than in trees with pseudococcids. Thus, the cost to the tree of maintaining ants may be greater when ants are associated with coccids. The net benefits to the plant of maintaining ants appear to be much greater with pseudococcids as the third partner. To explore how the type of homopteran affects functioning of the system, we attempted to determine which of the resources (nest sites, extrafloral nectar, and homopterans) is likely to limit ant colony size. In trees where ants tended coccids, ant-colony biomass was strongly dependent on the number of extrafloral nectaries. In contrast, in trees whose ants tended only pseudococcids, colony biomass was not related to the number of nectaries and was most strongly determined by the volume of available nest sites. We present hypotheses to explain how the type of
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Environmental changes during secondary succession in a tropical dry forest in Mexico
Lebrija Trejos, E.E.; Pérez-Garcia, E.A.; Meave, J.; Poorter, L.; Bongers, F.
2011-01-01
Vegetation and environment change mutually during secondary succession, yet the idiosyncrasies of the vegetation effect on the understorey environment are poorly understood. To test whether the successional understorey environment changes predictably and is shaped by the structure and seasonality of
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International Nuclear Information System (INIS)
Lee, Seung Min; Jang, In Seok; Seong, Poong Hyun
2009-01-01
It is important to communicate clearly and effectively in order to achieve and improve team performance, also in the view point of safety, in nuclear power plant (NPP). Researchers have studied on lots of accidents and incidents related to communication and analyzed the elements affecting communication fail in the side of sender-receiver communication process so that they have found which process was failed to communicate each other. But we cannot disregard on human cognition, level of understanding, and individual or team characteristic on the communication process, so we need to analyze the elements of communication-related events in the side of human and team components that we will find why operators could not avoid failing their communication. In this paper we enumerate key organizational components, collect events related to communication in NPP and count the total number of components affecting communication fail. Finally we perform the pairwise-comparison using those values and understand major factors affecting communication-related events
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Dusza, Yann; Barot, Sébastien; Kraepiel, Yvan; Lata, Jean-Christophe; Abbadie, Luc; Raynaud, Xavier
2017-04-01
Green roofs provide ecosystem services through evapotranspiration and nutrient cycling that depend, among others, on plant species, substrate type, and substrate depth. However, no study has assessed thoroughly how interactions between these factors alter ecosystem functions and multifunctionality of green roofs. We simulated some green roof conditions in a pot experiment. We planted 20 plant species from 10 genera and five families (Asteraceae, Caryophyllaceae, Crassulaceae, Fabaceae, and Poaceae) on two substrate types (natural vs. artificial) and two substrate depths (10 cm vs. 30 cm). As indicators of major ecosystem functions, we measured aboveground and belowground biomasses, foliar nitrogen and carbon content, foliar transpiration, substrate water retention, and dissolved organic carbon and nitrates in leachates. Interactions between substrate type and depth strongly affected ecosystem functions. Biomass production was increased in the artificial substrate and deeper substrates, as was water retention in most cases. In contrast, dissolved organic carbon leaching was higher in the artificial substrates. Except for the Fabaceae species, nitrate leaching was reduced in deep, natural soils. The highest transpiration rates were associated with natural soils. All functions were modulated by plant families or species. Plant effects differed according to the observed function and the type and depth of the substrate. Fabaceae species grown on natural soils had the most noticeable patterns, allowing high biomass production and high water retention but also high nitrate leaching from deep pots. No single combination of factors enhanced simultaneously all studied ecosystem functions, highlighting that soil-plant interactions induce trade-offs between ecosystem functions. Substrate type and depth interactions are major drivers for green roof multifunctionality.
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International Nuclear Information System (INIS)
Cline, J.F.; Hinds, W.T.
1976-06-01
Less 238 Pu was concentrated in the seeds than in the vegetative parts in all plant species. Leaves contained more 238 Pu than the stem or pods, and the monocots had lower concentrations of 238 Pu in their tissues than the dicots. Irrigation of plants affected the uptake of 238 Pu, especially on the year-to-year changes in the amount of the element accumulated in the plant parts. Several more years of data must be analyzed to determine if this phenomenon is real. Soil profiles must be studied to determine what configuration changes may occur in the 238 Pu in the soil. Other investigators show that soil microbes change the chemical form of plutonium in the soil and the organic complexes that are formed are more available for plant uptake
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Fast reactor system factors affecting reprocessing plant design
International Nuclear Information System (INIS)
Allardice, R.H.; Pugh, O.
1982-01-01
The introduction of a commercial fast reactor electricity generating system is very dependent on the availability of an efficient nuclear fuel cycle. Selection of fuel element constructional materials, the fuel element design approach and the reactor operation have a significant influence on the technical feasibility and efficiency of the reprocessing and waste management plants. Therefore the fast reactor processing plant requires liaison between many design teams -reactor, fuel design, reprocessing and waste management -often with different disciplines and conflicting objectives if taken in isolation and an optimised approach to determining several key parameters. A number of these parameters are identified and the design approach discussed in the context of the reprocessing plant. Radiological safety and its impact on design is also briefly discussed. (author)
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Piñero, María C; Pérez-Jiménez, Margarita; López-Marín, Josefa; Del Amor, Francisco M
2016-08-01
The assimilation and availability of nitrogen in its different forms can significantly affect the response of primary productivity under the current atmospheric alteration and soil degradation. An elevated CO2 concentration (e[CO2]) triggers changes in the efficiency and efficacy of photosynthetic processes, water use and product yield, the plant response to stress being altered with respect to ambient CO2 conditions (a[CO2]). Additionally, NH4(+) has been related to improved plant responses to stress, considering both energy efficiency in N-assimilation and the overcoming of the inhibition of photorespiration at e[CO2]. Therefore, the aim of this work was to determine the response of sweet pepper plants (Capsicum annuum L.) receiving an additional supply of NH4(+) (90/10 NO3(-)/NH4(+)) to salinity stress (60mM NaCl) under a[CO2] (400μmolmol(-1)) or e[CO2] (800μmolmol(-1)). Salt-stressed plants grown at e[CO2] showed DW accumulation similar to that of the non-stressed plants at a[CO2]. The supply of NH4(+) reduced growth at e[CO2] when salinity was imposed. Moreover, NH4(+) differentially affected the stomatal conductance and water use efficiency and the leaf Cl(-), K(+), and Na(+) concentrations, but the extent of the effects was influenced by the [CO2]. An antioxidant-related response was prompted by salinity, the total phenolics and proline concentrations being reduced by NH4(+) at e[CO2]. Our results show that the effect of NH4(+) on plant salinity tolerance should be globally re-evaluated as e[CO2] can significantly alter the response, when compared with previous studies at a[CO2]. Copyright © 2016 Elsevier GmbH. All rights reserved.
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Morawo, Tolulope; Fadamiro, Henry
2014-12-01
Volatile organic compounds (VOCs) released by herbivore-damaged plants can guide parasitoids to their hosts. The quantity and quality of VOC blends emitted by plants may be affected by the duration of plant damage by herbivores, which could have potential ramifications on the recruitment of competing parasitoids. We used two parasitoid species, Microplitis croceipes and Cotesia marginiventris (Hymenoptera: Braconidae), to address the question of whether duration of plant damage affects parasitoid use of plant VOCs for host location. Both wasp species are larval endoparasitoids of Heliothis virescens (Lepidoptera: Noctuidae), an important pest of cotton. Attraction of the two parasitoid species to odors emitted by undamaged (UD), fresh (6 h infestation) damage (FD), and old (24 h infestation) damage (OD) cotton plants infested by H. virescens larvae was investigated using a headspace volatile collection system coupled with four-choice olfactometer bioassay. Both sexes of M. croceipes showed a preference for FD- and OD-plant odors over UD-plants. On the other hand, more C. marginiventris females were attracted to UD- and FD-plants than to OD-plants. GC/MS analyses showed qualitative and quantitative differences in the VOC profiles of UD, FD, and OD-plants, which may explain the observed preferences of the parasitoids. These results suggest a temporal partitioning in the recruitment of M. croceipes and C. marginiventris to H. virescens-damaged cotton, and may have potential implications for interspecific competition between the two parasitoid species.
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Bioaerosols from a Food Waste Composting Plant Affect Human Airway Epithelial Cell Remodeling Genes
Chang, Ming-Wei; Lee, Chung-Ru; Hung, Hsueh-Fen; Teng, Kuo-Sheng; Huang, Hsin; Chuang, Chun-Yu
2013-01-01
The composting procedure in food waste plants generates airborne bioaerosols that have the potential to damage human airway epithelial cells. Persistent inflammation and repair responses induce airway remodeling and damage to the respiratory system. This study elucidated the expression changes of airway remodeling genes in human lung mucoepidermoid NCI-H292 cells exposed to bioaerosols from a composting plant. Different types of microorganisms were detectable in the composting plant, using the agar culture method. Real-time polymerase chain reaction was used to quantify the level of Aspergillus fumigatus and the profile of remodeling genes. The real-time PCR results indicated that the amount of A. fumigatus in the composting hall was less than 102 conidia. The endotoxins in the field bioaerosols were determined using a limulus amebocyte lysate test. The endotoxin levels depended on the type of particulate matter (PM), with coarse particles (2.5–10 μm) having higher endotoxin levels than did fine particles (0.5–2.5 μm). After exposure to the conditioned medium of field bioaerosol samples, NCI-H292 cells showed increased pro-inflammatory interleukin (IL)-6 release and activated epidermal growth factor receptor (EGFR), transforming growth factor (TGF)-β1 and cyclin-dependent kinase inhibitor 1 (p21WAF1/CIP1) gene expression, but not of matrix metallopeptidase (MMP)-9. Airborne endotoxin levels were higher inside the composting hall than they were in other areas, and they were associated with PM. This suggested that airborne bioaerosols in the composting plant contained endotoxins and microorganisms besides A. fumigatus that cause the inflammatory cytokine secretion and augment the expression of remodeling genes in NCI-H292 cells. It is thus necessary to monitor potentially hazardous materials from bioaerosols in food composting plants, which could affect the health of workers. PMID:24368426
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Bioaerosols from a food waste composting plant affect human airway epithelial cell remodeling genes.
Chang, Min-Wei; Lee, Chung-Ru; Hung, Hsueh-Fen; Teng, Kuo-Sheng; Huang, Hsin; Chuang, Chun-Yu
2013-12-24
The composting procedure in food waste plants generates airborne bioaerosols that have the potential to damage human airway epithelial cells. Persistent inflammation and repair responses induce airway remodeling and damage to the respiratory system. This study elucidated the expression changes of airway remodeling genes in human lung mucoepidermoid NCI-H292 cells exposed to bioaerosols from a composting plant. Different types of microorganisms were detectable in the composting plant, using the agar culture method. Real-time polymerase chain reaction was used to quantify the level of Aspergillus fumigatus and the profile of remodeling genes. The real-time PCR results indicated that the amount of A. fumigatus in the composting hall was less than 10(2) conidia. The endotoxins in the field bioaerosols were determined using a limulus amebocyte lysate test. The endotoxin levels depended on the type of particulate matter (PM), with coarse particles (2.5-10 μm) having higher endotoxin levels than did fine particles (0.5-2.5 μm). After exposure to the conditioned medium of field bioaerosol samples, NCI-H292 cells showed increased pro-inflammatory interleukin (IL)-6 release and activated epidermal growth factor receptor (EGFR), transforming growth factor (TGF)-β1 and cyclin-dependent kinase inhibitor 1 (p21 WAF1/CIP1) gene expression, but not of matrix metallopeptidase (MMP)-9. Airborne endotoxin levels were higher inside the composting hall than they were in other areas, and they were associated with PM. This suggested that airborne bioaerosols in the composting plant contained endotoxins and microorganisms besides A. fumigatus that cause the inflammatory cytokine secretion and augment the expression of remodeling genes in NCI-H292 cells. It is thus necessary to monitor potentially hazardous materials from bioaerosols in food composting plants, which could affect the health of workers.
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Bettini, Priscilla P; Marvasi, Massimiliano; Fani, Fabiola; Lazzara, Luigi; Cosi, Elena; Melani, Lorenzo; Mauro, Maria Luisa
2016-10-01
Insertion of Agrobacterium rhizogenes rolB gene into plant genome affects plant development, hormone balance and defence. However, beside the current research, the overall transcriptional response and gene expression of rolB as a modulator in plant is unknown. Transformed rolB tomato plant (Solanum lycopersicum L.) cultivar Tondino has been used to investigate the differential expression profile. Tomato is a well-known model organism both at the genetic and molecular level, and one of the most important commercial food crops in the world. Through the construction and characterization of a cDNA subtracted library, we have investigated the differential gene expression between transgenic clones of rolB and control tomato and have evaluated genes specifically transcribed in transgenic rolB plants. Among the selected genes, five genes encoding for chlorophyll a/b binding protein, carbonic anhydrase, cytochrome b 6 /f complex Fe-S subunit, potassium efflux antiporter 3, and chloroplast small heat-shock protein, all involved in chloroplast function, were identified. Measurement of photosynthesis efficiency by the level of three different photosynthetic parameters (F v /F m , rETR, NPQ) showed rolB significant increase in non-photochemical quenching and a, b chlorophyll content. Our results point to highlight the role of rolB on plant fitness by improving photosynthesis. Copyright © 2016 Elsevier GmbH. All rights reserved.
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Nitrogen fixed by wheat plants as affected by nitrogen fertilizer levels and Non-symbiotic bacteria
Energy Technology Data Exchange (ETDEWEB)
Soliman, S; Aly, S S.M.; Gadalla, A M [Soils and Water Dept., Atomic Energy Authority, Cairo (Egypt); Abou Seeda, M [Soils and Water Dept., National Res. Centre, Cairo (Egypt)
1995-10-01
Inorganic nitrogen is required for all egyptian soils for wheat. Free living and N 2-fixing microorganisms are able associate closely related with the roots of geraminacae. Pot experiment studies were carried out to examine the response of wheat plants to inoculation with Azospirillum Brasilense and Azotobacter Chroococcum, single or in combination, under various levels of ammonium sulfate interaction between both the inoculants increased straw or grain yield as well as N-uptake by wheat plants with increasing N levels. Results showed that grains of wheat plants derived over 19,24 and 15% of its N content from the atmospheric - N 2 (Ndfa) with application of 25,50 and 75 mg N kg-1 soil in the presence of + Azospirillum + azotobacter. The final amount of N 2-fixers. The highest values of N 2-fixed were observed with mixed inoculants followed by inoculation with Azospirillum and then azotobacter. The recovery of applied ammonium sulfate-N was markedly increased by inoculation with combined inoculants, but less in uninoculated treatments. Seeds inoculated with non-symbiotic fixing bacteria could be saved about 25 kg N without much affecting the grain yield. i fig., 4 tabs.
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Nitrogen fixed by wheat plants as affected by nitrogen fertilizer levels and Non-symbiotic bacteria
International Nuclear Information System (INIS)
Soliman, S.; Aly, S.S.M.; Gadalla, A.M.; Abou Seeda, M.
1995-01-01
Inorganic nitrogen is required for all egyptian soils for wheat. Free living and N 2-fixing microorganisms are able associate closely related with the roots of geraminacae. Pot experiment studies were carried out to examine the response of wheat plants to inoculation with Azospirillum Brasilense and Azotobacter Chroococcum, single or in combination, under various levels of ammonium sulfate interaction between both the inoculants increased straw or grain yield as well as N-uptake by wheat plants with increasing N levels. Results showed that grains of wheat plants derived over 19,24 and 15% of its N content from the atmospheric - N 2 (Ndfa) with application of 25,50 and 75 mg N kg-1 soil in the presence of + Azospirillum + azotobacter. The final amount of N 2-fixers. The highest values of N 2-fixed were observed with mixed inoculants followed by inoculation with Azospirillum and then azotobacter. The recovery of applied ammonium sulfate-N was markedly increased by inoculation with combined inoculants, but less in uninoculated treatments. Seeds inoculated with non-symbiotic fixing bacteria could be saved about 25 kg N without much affecting the grain yield. i fig., 4 tabs
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Plant surface wax affects parasitoid's response to host footprints
Rostás, Michael; Ruf, Daniel; Zabka, Vanessa; Hildebrandt, Ulrich
2008-10-01
The plant surface is the substrate upon which herbivorous insects and natural enemies meet and thus represents the stage for interactions between the three trophic levels. Plant surfaces are covered by an epicuticular wax layer which is highly variable depending on species, cultivar or plant part. Differences in wax chemistry may modulate ecological interactions. We explored whether caterpillars of Spodoptera frugiperda, when walking over a plant surface, leave a chemical trail (kairomones) that can be detected by the parasitoid Cotesia marginiventris. Chemistry and micromorphology of cuticular waxes of two barley eceriferum wax mutants ( cer-za.126, cer-yp.949) and wild-type cv. Bonus (wt) were assessed. The plants were then used to investigate potential surface effects on the detectability of caterpillar kairomones. Here we provide evidence that C. marginiventris responds to chemical footprints of its host. Parasitoids were able to detect the kairomone on wild-type plants and on both cer mutants but the response to cer-yp.949 (reduced wax, high aldehyde fraction) was less pronounced. Experiments with caterpillar-treated wt and mutant leaves offered simultaneously, confirmed this observation: no difference in wasp response was found when wt was tested against cer-za.126 (reduced wax, wt-like chemical composition) but wt was significantly more attractive than cer-yp.949. This demonstrates for the first time that the wax layer can modulate the detectability of host kairomones.
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International Nuclear Information System (INIS)
Kozak, M.; Havel, S.
1989-09-01
In Czechoslovakia, there are eight WWER 440 type reactors in operation at present. Since their introduction into operation, nuclear power plants in Czechoslovakia have exhibited high reliability. In the paper, total parameters of reliability with an analysis of causes affecting negatively their annual utilization are presented. Existence of a computerized information system for acquisition, recording and evaluation of reliability-significant data from operation and its feedback to designers and manufacturers of nuclear power plant equipment and components is a basic requirement of a systematic assurance of the needed level of nuclear power plant reliability. The information system is used simultaneously also for realistic evaluation of aging of equipment and systems. Analysis of the state of equipment is important mainly in the final stage of the NPP during consideration of further extension of its service life. Environmental effects of the Czechoslovak NPPs are very low (favourable). It follows from comparison of annual dose equivalents of the Czechoslovak NPPs operational personnel with the foreign NPPs that the values recorded in Czechoslovakia belong to the lowest ones. In conclusion, some ways of assurance of operational safety and reliability of the Czechoslovak nuclear power plants including the role of the State regulatory body are briefly discussed. (author). 3 tabs
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Multinationals and plant survival
DEFF Research Database (Denmark)
Bandick, Roger
2010-01-01
The aim of this paper is twofold: first, to investigate how different ownership structures affect plant survival, and second, to analyze how the presence of foreign multinational enterprises (MNEs) affects domestic plants’ survival. Using a unique and detailed data set on the Swedish manufacturing...... sector, I am able to separate plants into those owned by foreign MNEs, domestic MNEs, exporting non-MNEs, and purely domestic firms. In line with previous findings, the result, when conditioned on other factors affecting survival, shows that foreign MNE plants have lower survival rates than non......-MNE plants. However, separating the non-MNEs into exporters and non-exporters, the result shows that foreign MNE plants have higher survival rates than non-exporting non-MNEs, while the survival rates of foreign MNE plants and exporting non-MNE plants do not seem to differ. Moreover, the simple non...
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Spatial environmental heterogeneity affects plant growth and thermal performance on a green roof.
Buckland-Nicks, Michael; Heim, Amy; Lundholm, Jeremy
2016-05-15
Green roofs provide ecosystem services, including stormwater retention and reductions in heat transfer through the roof. Microclimates, as well as designed features of green roofs, such as substrate and vegetation, affect the magnitude of these services. Many green roofs are partially shaded by surrounding buildings, but the effects of this within-roof spatial environmental heterogeneity on thermal performance and other ecosystem services have not been examined. We quantified the effects of spatial heterogeneity in solar radiation, substrate depth and other variables affected by these drivers on vegetation and ecosystem services in an extensive green roof. Spatial heterogeneity in substrate depth and insolation were correlated with differential growth, survival and flowering in two focal plant species. These effects were likely driven by the resulting spatial heterogeneity in substrate temperature and moisture content. Thermal performance (indicated by heat flux and substrate temperature) was influenced by spatial heterogeneity in vegetation cover and substrate depth. Areas with less insolation were cooler in summer and had greater substrate moisture, leading to more favorable conditions for plant growth and survival. Spatial variation in substrate moisture (7%-26% volumetric moisture content) and temperature (21°C-36°C) during hot sunny conditions in summer could cause large differences in stormwater retention and heat flux within a single green roof. Shaded areas promote smaller heat fluxes through the roof, leading to energy savings, but lower evapotranspiration in these areas should reduce stormwater retention capacity. Spatial heterogeneity can thus result in trade-offs between different ecosystem services. The effects of these spatial heterogeneities are likely widespread in green roofs. Structures that provide shelter from sun and wind may be productively utilized to design higher functioning green roofs and increase biodiversity by providing habitat
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Cotrufo, M. F.; Alberti, G.; Inglima, I.; Marjanović, H.; Lecain, D.; Zaldei, A.; Peressotti, A.; Miglietta, F.
2011-06-01
Precipitation patterns are expected to change in the Mediterranean region within the next decades, with projected decreases in total rainfall and increases in extreme events. We manipulated precipitation patterns in a Mediterranean woodland, dominated by Arbutus unedo L., to study the effects of changing precipitation regimes on above-ground net primary production (ANPP) and soil C dynamics, specifically plant-derived C input to soil and soil respiration (SR). Experimental plots were exposed to either a 20 % reduction of throughfall or to water addition targeted at maintaining soil water content above a minimum of 10 % v/v. Treatments were compared to control plots which received ambient precipitation. The throughfall manipulation experiment started in 2004 and we report data up to the 2009 growing season. Enhanced soil moisture during summer months highly stimulated annual stem primary production, litter fall, SR and net annual plant-derived C input to soil which on average increased by 130 %, 26 %, 50 % and 220 %, respectively, as compared to control. In contrast, the 20 % reduction in throughfall (equivalent to 10 % reduction of precipitation) did not significantly change soil moisture at the site, and therefore did not significantly affect ANPP or SR. We conclude that minor changes (around 10 % reduction) in precipitation amount are not likely to significantly affect ANPP or soil C dynamics in Mediterranean woodland. However, if summer rain increases, C cycling will significantly accelerate but soil C stocks are not likely to be changed in the short-term. More studies involving modelling of long term C dynamics are needed to predict if the estimated increases in soil C input under wet conditions is going to be sustained and if labile C is being substituted to stable C, with a negative effect on long term soil C stocks.
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Plant extracts affect in vitro rumen microbial fermentation.
Busquet, M; Calsamiglia, S; Ferret, A; Kamel, C
2006-02-01
Different doses of 12 plant extracts and 6 secondary plant metabolites were incubated for 24 h in diluted ruminal fluid with a 50:50 forage:concentrate diet. Treatments were: control (no additive), plant extracts (anise oil, cade oil, capsicum oil, cinnamon oil, clove bud oil, dill oil, fenugreek, garlic oil, ginger oil, oregano oil, tea tree oil, and yucca), and secondary plant metabolites (anethol, benzyl salicylate, carvacrol, carvone, cinnamaldehyde, and eugenol). Each treatment was supplied at 3, 30, 300, and 3,000 mg/L of culture fluid. At 3,000 mg/L, most treatments decreased total volatile fatty acid concentration, but cade oil, capsicum oil, dill oil, fenugreek, ginger oil, and yucca had no effect. Different doses of anethol, anise oil, carvone, and tea tree oil decreased the proportion of acetate and propionate, which suggests that these compounds may not be nutritionally beneficial to dairy cattle. Garlic oil (300 and 3,000 mg/L) and benzyl salicylate (300 and 3,000 mg/L) reduced acetate and increased propionate and butyrate proportions, suggesting that methane production was inhibited. At 3,000 mg/L, capsicum oil, carvacrol, carvone, cinnamaldehyde, cinnamon oil, clove bud oil, eugenol, fenugreek, and oregano oil resulted in a 30 to 50% reduction in ammonia N concentration. Careful selection and combination of these extracts may allow the manipulation of rumen microbial fermentation.
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Does plant diversity affect the water balance of established grassland systems?
Leimer, Sophia; Bischoff, Sebastian; Blaser, Stefan; Boch, Steffen; Busch, Verena; Escher, Peter; Fischer, Markus; Kaupenjohann, Martin; Kerber, Katja; Klaus, Valentin; Michalzik, Beate; Prati, Daniel; Schäfer, Deborah; Schmitt, Barbara; Schöning, Ingo; Schwarz, Martin T.; Siemens, Jan; Thieme, Lisa; Wilcke, Wolfgang
2017-04-01
The water cycle drives nutrient cycles and plant productivity. The impact of land use on the water cycle has been extensively studied and there is experimental evidence that biodiversity modifies the water cycle in grasslands. However, the combined influences of land-use and associated biodiversity on the water cycle in established land-use systems are unclear. Therefore, we investigated how evapotranspiration (ETa), downward water flux (DF), and capillary rise (CR) in topsoil and subsoil are related to land-use and plant diversity in established, commercially managed grassland and compared these results to findings from experiments where plant diversity was manipulated. In three Central European regions ("Biodiversity Exploratories"), we studied 29 grassland plots (50 m x 50 m; 9-11 plots per region) from 2010 to 2015. The land-use types cover pasture, mown pasture, and meadow in at least triplicate per region. On each plot, we measured soil water contents, meteorological data (hourly resolution), cumulative precipitation (biweekly), plant species richness, the number of plants in the functional groups of grasses, herbs, and legumes (annually), and root biomass (once). Potential evapotranspiration (ETp) was calculated from meteorological data per plot. Missing data points of ETp and soil water contents were estimated with Bayesian hierarchical models. ETa, DF, and CR were calculated for two soil layers with a soil water balance model. The model is based on changes in soil water storage between subsequent observation dates and ETp, which was partitioned between soil layers according to root distribution. Water fluxes in annual resolution were statistically analyzed for land-use and biodiversity effects using repeated-measures analysis of variance (ANOVA). Land-use type did not affect water fluxes. Species richness did not influence DF and CR. DF from topsoil was higher on plots with more grass species, which is opposite to the results from a manipulative
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Factors affecting heavy metal uptake in plant selection for phytoremediation
Energy Technology Data Exchange (ETDEWEB)
Anton, A.; Mathe-Gaspar, G. [Research Inst. for Soil Science and Agricultural Chemistry of the Hungarian Academy of Sciences, Budapest (Hungary)
2005-04-01
The heavy metal uptake of ten plant species was studied under different soil and climatic conditions. Effects of soil pH, temperature, plant species and phenophase on the heavy metal content of stems and leaves were determined in pot experiments. Plants and soil samples were collected from a lead/zinc mine ore (Gyoengyoesoroszi, Hungary) and characterised by high contents of Pb, Zn, As, Cd, Cu. The possibility of an adapted phytoremediation technology was indicated by different bioconcentration factors (BCF). The BCF depended markedly (10- to 100-fold) on plant species and environmental conditions. Based on our results a ''season-adapted'' phytoextraction technology with different plant species (utilising their different temperature requirements and/or harvest time) is suggested. (orig.)
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Directory of Open Access Journals (Sweden)
Ashraf eEl-Kereamy
2015-11-01
Full Text Available Glutaredoxins (GRXs are small glutathione dependent oxidoreductases that belong to the Thioredoxin (TRX superfamily and catalyze the reduction of disulfide bonds of their substrate proteins. Plant GRXs include three different groups based on the motif sequence, namely CPYC, CGFS and CC-type proteins. The rice CC-type proteins, OsGRX6 was identified during the screening for genes whose expression changes depending on the level of available nitrate. Overexpression of OsGRX6 in rice displayed a semi-dwarf phenotype. The OsGRX6 overexpressors contain a higher nitrogen content than the wild type, indicating that OsGRX6 plays a role in homeostatic regulation of nitrogen use. Consistent with this, OsGRX6 overexpressors displayed delayed chlorophyll degradation and senescence compared to the wild type plants. To examine if the growth defect of these transgenic lines attribute to disturbed plant hormone actions, plant hormone levels were measured. The levels of two cytokinins (CKs, 2-isopentenyladenine and trans-zeatin, and gibberellin A1 (GA1 were increased in these lines. We also found that these transgenic lines were less sensitive to exogenously applied GA, suggesting that the increase in GA1 is a result of the feedback regulation. These data suggest that OsGRX6 affects hormone signaling and nitrogen status in rice plants.
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Directory of Open Access Journals (Sweden)
Gustavo Habermann
2006-01-01
Full Text Available Citrus variegated chlorosis (CVC is a disease caused by Xylella fastidiosa. Using different concentrations of plant regulators, such as auxins (indole-3-butyric acid and gibberellic acid biosynthesis-inhibitor (paclobutrazol, physiological rooting capacity of healthy and CVC-affected stem cuttings were evaluated in order to investigate the importance of plant hormone imbalance and xylem occlusion in plants with CVC. The percentages of dead, alive and rooted cuttings, cuttings with callus and mean number of roots per cuttings did not show statistical differences in response to the distinct concentrations of synthetic plant regulators. There were differences only between healthy and CVC-affected cuttings. This showed the importance of xylem occlusion and diffusive disturbances in diseased plants, in relation to root initiation capacity and hormonal translocation in the plant tissue.Clorose variegada dos citros (CVC é uma doença causada por Xylella fastidiosa, podendo determinar oclusão do xilema e desbalanço hormonal, o que por fim está relacionado ao processo de iniciação radicial em estacas. Usando diferentes concentrações de fitorreguladores, como auxinas (ácido 3-indol butírico e inibidores da biossíntese de ácido giberélico (paclobutrazol, que são promotores do enraizamento de estacas, verificou-se a capacidade fisiológica de enraizamento de estacas sadias e com CVC, a fim de investigar a importância do desbalanço hormonal e oclusão do xilema em plantas doentes. As porcentagens de estacas mortas, vivas, enraizadas e com calo e o número médio de raízes por estaca não mostraram diferenças estatísticas em resposta às diferentes concentrações dos reguladores vegetais sintéticos. Houve diferenças apenas entre estacas sadias e doentes. Isto aponta a importância da oclusão do xilema e distúrbios difusivos em plantas doentes, em relação à capacidade de iniciação radicial e à translocação hormonal no tecido
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Unpreferred plants affect patch choice and spatial distribution of European brown hares
Kuijper, D. P. J.; Bakker, J. P.
2008-11-01
Many herbivore species prefer to forage on patches of intermediate biomass. Plant quality and forage efficiency are predicted to decrease with increasing plant standing crop which explains the lower preference of the herbivore. However, often is ignored that on the long-term, plant species composition is predicted to change with increasing plant standing crop. The amount of low-quality, unpreferred food plants increases with increasing plant standing crop. In the present study the effects of unpreferred plants on patch choice and distribution of European brown hare in a salt-marsh system were studied. In one experiment, unpreferred plants were removed from plots. In the second experiment, plots were planted with different densities of an unpreferred artificial plant. Removal of unpreferred plants increased hare-grazing pressure more than fivefold compared to unmanipulated plots. Planting of unpreferred plants reduced hare-grazing pressure, with a significant reduction of grazing already occurring at low unpreferred plant density. Spatial distribution of hares within this salt-marsh system was related to spatial arrangement of unpreferred plants. Hare-grazing intensity decreased strongly with increasing abundance of unpreferred plants despite a high abundance of principal food plants. The results of this study indicate that plant species replacement is an important factor determining patch choice and spatial distribution of hares next to changing plant quality. Increasing abundance of unpreferred plant species can strengthen the decreasing patch quality with increasing standing crop and can decrease grazing intensity when preferred food plants are still abundantly present.
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Cotrufo, M. F.; Alberti, G.; Inglima, I.; Marjanović, H.; Lecain, D.; Zaldei, A.; Peressotti, A.; Miglietta, F.
2011-09-01
Precipitation patterns are expected to change in the Mediterranean region within the next decades, with projected decreases in total rainfall and increases in extreme events. We manipulated precipitation patterns in a Mediterranean woodland, dominated by Arbutus unedo L., to study the effects of changing precipitation regimes on above-ground net primary production (ANPP) and soil C dynamics, specifically plant-derived C input to soil and soil respiration (SR). Experimental plots were exposed to either a 20 % reduction of throughfall or to water addition targeted at maintaining soil water content above a minimum of 10 % v/v. Treatments were compared to control plots which received ambient precipitation. Enhanced soil moisture during summer months highly stimulated annual stem primary production, litter fall, SR and net annual plant-derived C input to soil which on average increased by 130 %, 26 %, 58 % and 220 %, respectively, as compared to the control. In contrast, the 20 % reduction in throughfall (equivalent to 10 % reduction in precipitation) did not significantly change soil moisture at the site, and therefore did not significantly affect ANPP or SR. We conclude that minor changes (around 10 % reduction) in precipitation amount are not likely to significantly affect ANPP or soil C dynamics in Mediterranean woodlands. However, if summer rain increases, C cycling will significantly accelerate but soil C stocks are not likely to be changed in the short-term. More studies involving modelling of long-term C dynamics are needed to predict if the estimated increases in soil C input under wet conditions is going to be sustained and if labile C is being substituted to stable C, with a negative effect on long-term soil C stocks.
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How Will Global Environmental Changes Affect the Growth of Alien Plants?
Directory of Open Access Journals (Sweden)
Jujie Jia
2016-11-01
Full Text Available Global environmental changes can create novel habitats, promoting the growth of alien plants that often exhibit broad environmental tolerance and high phenotypic plasticity. However, the mechanisms underlying these growth promotory effects are unknown at present. Here, we conducted a phylogenetically controlled meta-analysis using data from 111 published studies encompassing the responses of 129 alien plants to global warming, increased precipitation, N deposition, and CO2 enrichment. We compared the differences in the responses of alien plants to the four global environmental change factors across six categories of functional traits between woody and non-woody life forms as well as C3 and C4 photosynthetic pathways. Our results showed that all four global change factors promote alien plant growth. Warming had a more positive effect on C4 than C3 plants. Although the effects of the four factors on the functional traits of alien plants were variable, plant growth was mainly promoted via an increase in growth rate and size. Our data suggest that potential future global environmental changes could further facilitate alien plant growth.
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A novel family of small proteins that affect plant development
Energy Technology Data Exchange (ETDEWEB)
John Charles Walker
2011-04-29
The DVL genes represent a new group of plant proteins that influence plant growth and development. Overexpression of DVL1, and other members of the DVL family, causes striking phenotypic changes. The DVL proteins share sequence homology in their C-terminal half. Point mutations in the C-terminal domain show it is necessary and deletion studies demonstrate the C-terminal domain is sufficient to confer the overexpression phenotypes. The phenotypes observed, and the conservation of the protein sequence in the plant kingdom, does suggest the DVL proteins have a role in modulating plant growth and development. Our working hypothesis is the DVL proteins function as regulators of cellular signaling pathways that control growth and development.
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Stand-level variation in evapotranspiration in non-water-limited eucalypt forests
Benyon, Richard G.; Nolan, Rachael H.; Hawthorn, Sandra N. D.; Lane, Patrick N. J.
2017-08-01
To better understand water and energy cycles in forests over years to decades, measurements of spatial and long-term temporal variability in evapotranspiration (Ea) are needed. In mountainous terrain, plot-level measurements are important to achieving this. Forest inventory data including tree density and size measurements, often collected repeatedly over decades, sample the variability occurring within the geographic and topographic range of specific forest types. Using simple allometric relationships, tree stocking and size data can be used to estimate variables including sapwood area index (SAI), which may be strongly correlated with annual Ea. This study analysed plot-level variability in SAI and its relationship with overstorey and understorey transpiration, interception and evaporation over a 670 m elevation gradient, in non-water-limited, even-aged stands of Eucalyptus regnans F. Muell. to determine how well spatial variation in annual Ea from forests can be mapped using SAI. Over the 3 year study, mean sap velocity in five E. regnans stands was uncorrelated with overstorey sapwood area index (SAI) or elevation: annual transpiration was predicted well by SAI (R2 0.98). Overstorey and total annual interception were positively correlated with SAI (R2 0.90 and 0.75). Ea from the understorey was strongly correlated with vapour pressure deficit (VPD) and net radiation (Rn) measured just above the understorey, but relationships between understorey Ea and VPD and Rn differed between understorey types and understorey annual Ea was not correlated with SAI. Annual total Ea was also strongly correlated with SAI: the relationship being similar to two previous studies in the same region, despite differences in stand age and species. Thus, spatial variation in annual Ea can be reliably mapped using measurements of SAI.
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Chronic human disturbance affects plant trait distribution in a seasonally dry tropical forest
Sfair, Julia C.; de Bello, Francesco; de França, Thaysa Q.; Baldauf, Cristina; Tabarelli, Marcelo
2018-02-01
The effects of human disturbance on biodiversity can be mediated by environmental conditions, such as water availability, climate and nutrients. In general, disturbed, dry or nutrient-depleted soils areas tend to have lower taxonomic diversity. However, little is known about how these environmental conditions affect functional composition and intraspecific variability in tropical dry forests. We studied a seasonally dry tropical forest (SDTF) under chronic anthropogenic disturbance (CAD) along rainfall and soil nutrient gradients to understand how these factors influence the taxonomic and functional composition. Specifically we evaluated two aspects of CAD, wood extraction and livestock pressure (goat and cattle grazing), along soil fertility and rainfall gradients on shrub and tree traits, considering species turnover and intraspecific variability. In addition, we also tested how the traits of eight populations of the most frequent species are affected by wood extraction, livestock pressure, rainfall and soil fertility. In general, although CAD and environmental gradients affected each trait of the most widespread species differently, the most abundant species also had a greater variation of traits. Considering species turnover, wood extraction is associated with species with a smaller leaf area and lower investment in leaf mass, probably due to the indirect effects of this disturbance type on the vegetation, i.e. the removal of branches and woody debris clears the vegetation, favouring species that minimize water loss. Livestock pressure, on the other hand, affected intraspecific variation: the herbivory caused by goats and cattle promoted individuals which invest more in wood density and leaf mass. In this case, the change of functional composition observed is a direct effect of the disturbance, such as the decrease of palatable plant abundance by goat and cattle herbivory. In synthesis, CAD, rainfall and soil fertility can affect trait distribution at community
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Plant traits related to nitrogen uptake influence plant-microbe competition.
Moreau, Delphine; Pivato, Barbara; Bru, David; Busset, Hugues; Deau, Florence; Faivre, Céline; Matejicek, Annick; Strbik, Florence; Philippot, Laurent; Mougel, Christophe
2015-08-01
Plant species are important drivers of soil microbial communities. However, how plant functional traits are shaping these communities has received less attention though linking plant and microbial traits is crucial for better understanding plant-microbe interactions. Our objective was to determine how plant-microbe interactions were affected by plant traits. Specifically we analyzed how interactions between plant species and microbes involved in nitrogen cycling were affected by plant traits related to 'nitrogen nutrition in interaction with soil nitrogen availability. Eleven plant species, selected along an oligotrophic-nitrophilic gradient, were grown individually in a nitrogen-poor soil with two levels of nitrate availability. Plant traits for both carbon and nitrogen nutrition were measured and the genetic structure and abundance of rhizosphere. microbial communities, in particular the ammonia oxidizer and nitrate reducer guilds, were analyzed. The structure of the bacterial community in the rhizosphere differed significantly between plant species and these differences depended on nitrogen availability. The results suggest that the rate of nitrogen uptake per unit of root biomass and per day is a key plant trait, explaining why the effect of nitrogen availability on the structure of the bacterial community depends on the plant species. We also showed that the abundance of nitrate reducing bacteria always decreased with increasing nitrogen uptake per unit of root biomass per day, indicating that there was competition for nitrate between plants and nitrate reducing bacteria. This study demonstrates that nitrate-reducing microorganisms may be adversely affected by plants with a high nitrogen uptake rate. Our work puts forward the role of traits related to nitrogen in plant-microbe interactions, whereas carbon is commonly considered as the main driver. It also suggests that plant traits related to ecophysiological processes, such as nitrogen uptake rates, are more
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International Nuclear Information System (INIS)
Mahmood, A.; Hussain, A.; Shahzad, A. N.; Honermeier, B.
2015-01-01
Biogas from biomass is a promising renewable energy source whose importance is increasing in European as well as in other countries. A field experiment at one location (Experimental Station Giessen, Justus Liebig University of Giessen, Germany) over two years was designed to study the effect of altering sowing time (ST), planting density and cultivar on the biomass yield and chemical composition of biomass sorghum, and its potential for methane production. Of the two cultivars tested, cv. Goliath (intraspecific hybrid) was more productive with respect to biomass yield than cv. Bovital (S. bicolor x S. sudanense hybrid). ST also influenced biomass yield and most of the quality parameters measured. Delayed sowing was in general advantageous. The choice of cultivar had a marked effect on biogas and methane yield. The highest biogas and methane yields were produced by late sown cv. Bovital. Sub-optimal planting densities limited biomass accumulation of the crop, however neither the chemical composition nor the methane yield was affected by planting density. (author)
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Directory of Open Access Journals (Sweden)
M. F. Cotrufo
2011-09-01
Full Text Available Precipitation patterns are expected to change in the Mediterranean region within the next decades, with projected decreases in total rainfall and increases in extreme events. We manipulated precipitation patterns in a Mediterranean woodland, dominated by Arbutus unedo L., to study the effects of changing precipitation regimes on above-ground net primary production (ANPP and soil C dynamics, specifically plant-derived C input to soil and soil respiration (SR. Experimental plots were exposed to either a 20 % reduction of throughfall or to water addition targeted at maintaining soil water content above a minimum of 10 % v/v. Treatments were compared to control plots which received ambient precipitation. Enhanced soil moisture during summer months highly stimulated annual stem primary production, litter fall, SR and net annual plant-derived C input to soil which on average increased by 130 %, 26 %, 58 % and 220 %, respectively, as compared to the control. In contrast, the 20 % reduction in throughfall (equivalent to 10 % reduction in precipitation did not significantly change soil moisture at the site, and therefore did not significantly affect ANPP or SR. We conclude that minor changes (around 10 % reduction in precipitation amount are not likely to significantly affect ANPP or soil C dynamics in Mediterranean woodlands. However, if summer rain increases, C cycling will significantly accelerate but soil C stocks are not likely to be changed in the short-term. More studies involving modelling of long-term C dynamics are needed to predict if the estimated increases in soil C input under wet conditions is going to be sustained and if labile C is being substituted to stable C, with a negative effect on long-term soil C stocks.
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Light Influences How the Fungal Toxin Deoxynivalenol Affects Plant Cell Death and Defense Responses
Directory of Open Access Journals (Sweden)
Khairul I. Ansari
2014-02-01
Full Text Available The Fusarium mycotoxin deoxynivalenol (DON can cause cell death in wheat (Triticum aestivum, but can also reduce the level of cell death caused by heat shock in Arabidopsis (Arabidopsis thaliana cell cultures. We show that 10 μg mL−1 DON does not cause cell death in Arabidopsis cell cultures, and its ability to retard heat-induced cell death is light dependent. Under dark conditions, it actually promoted heat-induced cell death. Wheat cultivars differ in their ability to resist this toxin, and we investigated if the ability of wheat to mount defense responses was light dependent. We found no evidence that light affected the transcription of defense genes in DON-treated roots of seedlings of two wheat cultivars, namely cultivar CM82036 that is resistant to DON-induced bleaching of spikelet tissue and cultivar Remus that is not. However, DON treatment of roots led to genotype-dependent and light-enhanced defense transcript accumulation in coleoptiles. Wheat transcripts encoding a phenylalanine ammonia lyase (PAL gene (previously associated with Fusarium resistance, non-expressor of pathogenesis-related genes-1 (NPR1 and a class III plant peroxidase (POX were DON-upregulated in coleoptiles of wheat cultivar CM82036 but not of cultivar Remus, and DON-upregulation of these transcripts in cultivar CM82036 was light enhanced. Light and genotype-dependent differences in the DON/DON derivative content of coleoptiles were also observed. These results, coupled with previous findings regarding the effect of DON on plants, show that light either directly or indirectly influences the plant defense responses to DON.
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How genetic modification of roots affects rhizosphere processes and plant performance
Kabouw, P.; Van Dam, N.M.; Van der Putten, W.H.; Biere, A.
2012-01-01
Genetic modification of plants has become common practice. However, root-specific genetic modifications have only recently been advocated. Here, a review is presented regarding how root-specific modifications can have both plant internal and rhizosphere-mediated effects on aboveground plant
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International Nuclear Information System (INIS)
Munier-Lamy, C.; Deneux-Mustin, S.; Mustin, C.; Merlet, D.; Berthelin, J.; Leyval, C.
2007-01-01
The aim of this study was to investigate the influence of plant species, especially of their rhizosphere soil, and of inoculation with an arbuscular mycorrhizal (AM) fungus on the bioavailability of selenium and its transfer in soil-plant systems. A pot experiment was performed with a loamy clay soil and four plant species: maize, lettuce, radish and ryegrass, the last one being inoculated or not with an arbuscular mycorrhizal fungus (Glomus mosseae). Plant biomass and Se concentration in shoots and roots were estimated at harvest. Se bioavailability in rhizosphere and unplanted soil was evaluated using sequential extractions. Plant biomass and selenium uptake varied with plant species. The quantity of rhizosphere soil also differed between plants and was not proportional to plant biomass. The highest plant biomass, Se concentration in plants, and soil to plant transfer factor were obtained with radish. The lowest Se transfer factors were obtained with ryegrass. For the latter, mycorrhizal inoculation did not significantly affect plant growth, but reduced selenium transfer from soil to plant by 30%. In unplanted soil after 65 days aging, more than 90% of added Se was water-extractable. On the contrary, Se concentration in water extracts of rhizosphere soil represented less than 1% and 20% of added Se for ryegrass and maize, respectively. No correlation was found between the water-extractable fraction and Se concentration in plants. The speciation of selenium in the water extracts indicated that selenate was reduced, may be under organic forms, in the rhizosphere soil
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Decoupling factors affecting plant diversity and cover on extensive green roofs.
MacIvor, J Scott; Margolis, Liat; Puncher, Curtis L; Carver Matthews, Benjamin J
2013-11-30
Supplemental irrigation systems are often specified on green roofs to ensure plant cover and growth, both important components of green roof performance and aesthetics. Properties of the growing media environment too can alter the assemblage of plant species able to thrive. In this study we determine how plant cover, above ground biomass and species diversity are influenced by irrigation and growing media. Grass and forb vegetative cover and biomass were significantly greater in organic based growing media but there was no effect of supplemental irrigation, with two warm season grasses dominating in those treatments receiving no supplemental irrigation. On the other hand, plant diversity declined without irrigation in organic media, and having no irrigation in inorganic growing media resulted in almost a complete loss of cover. Sedum biomass was less in inorganic growing media treatments and species dominance shifted when growing media organic content increased. Our results demonstrate that supplemental irrigation is required to maintain plant diversity on an extensive green roof, but not necessarily plant cover or biomass. These results provide evidence that planting extensive green roofs with a mix of plant species can ensure the survival of some species; maintaining cover and biomass when supplemental irrigation is turned off to conserve water, or during extreme drought. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.
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Gehring, Christoph A.
2010-09-01
Immunologic evidence has suggested the presence of biologically active natriuretic peptide (NPs) hormones in plants because antiatrial NP antibodies affinity purify biologically active plant NPs (PNP). In the model plant, an Arabidopsis thaliana PNP (AtPNP-A) has been identified and characterized. AtPNP-A belongs to a novel class of molecules that share some similarity with the cell wall loosening expansins but do not contain the carbohydrate-binding wall anchor thus suggesting that PNPs and atrial natriuretic peptides are heterologs. AtPNP-A acts systemically, and this is consistent with its localization in the apoplastic extracellular space and the conductive tissue. Furthermore, AtPNP-A signals via the second messenger cyclic guanosine 3′,5′-monophosphate and modulates ion and water transport and homeostasis. It also plays a critical role in host defense against pathogens. AtPNP-A can be classified as novel paracrine plant hormone because it is secreted into the apoplastic space in response to stress and can enhance its own expression. Interestingly, purified recombinant PNP induces apo-ptosis in a dose-dependent manner and was most effective on cardiac myoblast cell lines. Because PNP is mimicking the effect of ANP in some instances, PNP may prove to provide useful leads for development of novel therapeutic NPs. Copyright © 2013 by The American Federation for Medical Research.
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Gehring, Christoph A; Irving, Helen R.
2010-01-01
Immunologic evidence has suggested the presence of biologically active natriuretic peptide (NPs) hormones in plants because antiatrial NP antibodies affinity purify biologically active plant NPs (PNP). In the model plant, an Arabidopsis thaliana PNP (AtPNP-A) has been identified and characterized. AtPNP-A belongs to a novel class of molecules that share some similarity with the cell wall loosening expansins but do not contain the carbohydrate-binding wall anchor thus suggesting that PNPs and atrial natriuretic peptides are heterologs. AtPNP-A acts systemically, and this is consistent with its localization in the apoplastic extracellular space and the conductive tissue. Furthermore, AtPNP-A signals via the second messenger cyclic guanosine 3′,5′-monophosphate and modulates ion and water transport and homeostasis. It also plays a critical role in host defense against pathogens. AtPNP-A can be classified as novel paracrine plant hormone because it is secreted into the apoplastic space in response to stress and can enhance its own expression. Interestingly, purified recombinant PNP induces apo-ptosis in a dose-dependent manner and was most effective on cardiac myoblast cell lines. Because PNP is mimicking the effect of ANP in some instances, PNP may prove to provide useful leads for development of novel therapeutic NPs. Copyright © 2013 by The American Federation for Medical Research.
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International Nuclear Information System (INIS)
Yuncal, A.
2000-01-01
A socioeconomic analysis performed for rural communities affected by industrial sites, namely for the case of nuclear power plants in Spain a common proposal for all the European countries is made. Existence of a common European program that could cover the following aspects: Creation of a Committee to enhance the participation in decision making process on different aspects, information policies, security, transport, waste management, investments, economic development; Contract between local authorities, State and companies responsibilities and financing; Legal framework of political organization; common socio-economic program including environment, employment, companies activities, responsibilities, taxes
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Factors affecting potential market penetration of laser fusion power plants
International Nuclear Information System (INIS)
Deonigi, D.E.; Fraley, D.W.
1979-08-01
A mini-model has been constructed to estimate the optimal size of laser fusion power plants and to estimate the allowable cost of the first such plant in relation to the next best alternative. In estimating the costs of laser fusion, the mini-model incorporates such factors as market penetration, learning, economies of scale, system size, transmission costs, reserve requirements, development and licensing costs and site costs. The results of the mini-model simulations indicate that the optimal laser fusion plant size is approximately 3 GWe; risk considerations unincorporated in the mini-model suggest an optimal size closer to 2.5 GWe
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Host plant affects morphometric variation of Diaphorina citri (Hemiptera: Liviidae
Directory of Open Access Journals (Sweden)
Thomson M. Paris
2016-11-01
Full Text Available The Asian citrus psyllid (ACP, Diaphorina citri Kuwayama, is one of the most serious citrus pests worldwide due to its role as vector of huanglongbing or citrus greening disease. While some optimal plant species for ACP oviposition and development have been identified, little is known of the influence of host plants on ACP size and shape. Our goal was to determine how size and shape of ACP wing and body size varies when development occurs on different host plants in a controlled rearing environment. ACP were reared on six different rutaceous species; Bergera koenigii, Citrus aurantifolia, Citrus macrophylla, Citrus maxima, Citrus taiwanica and Murraya paniculata. Adults were examined for morphometric variation using traditional and geometric analysis based on 12 traits or landmarks. ACP reared on C. taiwanica were consistently smaller than those reared on the other plant species. Wing aspect ratio also differed between C. maxima and C. taiwanica. Significant differences in shape were detected with those reared on M. paniculata having narrower wings than those reared on C. macrophylla. This study provides evidence of wing size and shape differences of ACP based on host plant species which potentially may impact dispersal. Further study is needed to determine if behavioral and physiological differences are associated with the observed phenotypic differences.
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Host plant affects morphometric variation of Diaphorina citri (Hemiptera: Liviidae).
Paris, Thomson M; Allan, Sandra A; Hall, David G; Hentz, Matthew G; Hetesy, Gabriella; Stansly, Philip A
2016-01-01
The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama, is one of the most serious citrus pests worldwide due to its role as vector of huanglongbing or citrus greening disease. While some optimal plant species for ACP oviposition and development have been identified, little is known of the influence of host plants on ACP size and shape. Our goal was to determine how size and shape of ACP wing and body size varies when development occurs on different host plants in a controlled rearing environment. ACP were reared on six different rutaceous species; Bergera koenigii , Citrus aurantifolia , Citrus macrophylla , Citrus maxima , Citrus taiwanica and Murraya paniculata . Adults were examined for morphometric variation using traditional and geometric analysis based on 12 traits or landmarks. ACP reared on C. taiwanica were consistently smaller than those reared on the other plant species. Wing aspect ratio also differed between C. maxima and C. taiwanica . Significant differences in shape were detected with those reared on M. paniculata having narrower wings than those reared on C. macrophylla . This study provides evidence of wing size and shape differences of ACP based on host plant species which potentially may impact dispersal. Further study is needed to determine if behavioral and physiological differences are associated with the observed phenotypic differences.
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Kostenko, O.; Mulder, Patrick P. J.; Courbois, Matthijs; Bezemer, T. Martijn
2017-01-01
1.The diversity of the surrounding plant community can directly affect the abundance of insects on a focal plant as well as the size and quality of that focal plant. However, to what extent the effects of plant diversity on the arthropod community on a focal plant are mediated by host plant quality
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Engel, C.; Weltzin, J.; Norby, R.
2004-12-01
Plant community composition and ecosystem function may be altered by global atmospheric and climate change, including increased atmospheric [CO2], temperature, and varying precipitation regimes. We are conducting an experiment at Oak Ridge National Laboratory (ORNL) utilizing open-top chambers to administer experimental treatments of elevated CO2 (+300 ppm), warming (+ 3 degrees Celsius), and varying soil moisture availability to experimental plant communities constructed of seven common old-field species, including C3 and C4 grasses, forbs, and legumes. During 2004 we monitored plant community phenology (NDVI) and plant reproductive phenology. Early in the year, NDVI was greater in wet treatment plots, and was unaffected by main effects of temperature or CO2. This result suggests that early in the season warming is insufficient to affect early canopy development. Differences in soil moisture sustained throughout the winter and into early spring may constitute an important control on early canopy greenup. Elevated CO2 alleviated detrimental effects of warming on NDVI, but only early in the season. As ambient temperatures increased, elevated temperatures negatively impacted NDVI only in the dry plots. Wetter conditions ameliorate the effects of warming on canopy greenness during the warmer seasons of the year. Warming increased rates of bolting, number of inflorescences, and time to reproductive maturity for Andropogon virginicus (a C4 bunchgrass). Solidago Canadensis (a C3 late-season forb) also produced flowers earlier in elevated temperatures. Conversely, none of the C3 grasses and forbs that bolt or flower in late spring or early summer responded to temperature or CO2. Results indicate that warming and drought may impact plant community phenology, and plant species reproductive phenology. Clearly community phenology is driven by complex interactions among temperature, water, and CO2 that change throughout the season. Our data stresses the importance of
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Directory of Open Access Journals (Sweden)
Hardy Olivier J
2009-07-01
differences in stature, as proposed earlier, but rather to differences in generation time. Conclusion Plant traits correlated with generation time affect both inbreeding depression and mating system. These in turn modify genetic drift and gene flow and ultimately genetic structure.
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Aridity influences the recovery of vegetation and shrubland birds after wildfire.
Puig-Gironès, Roger; Brotons, Lluís; Pons, Pere
2017-01-01
Wildfires play a determining role in the composition and structure of many plant and animal communities. On the other hand, climate change is considered to be a major driver of current and future fire regime changes. Despite increases in drought in many areas of the world, the effects of aridity on post-fire colonization by animals have been rarely addressed. This study aims to analyse how a regional aridity gradient affects post-fire recovery of vegetation, bird species richness and the numbers of four early to middle-successional warbler species associated with the shrub cover. The database contains bird relative abundance and environmental variables from 3072 censuses in 695 transects located in 70 recently burnt areas (1 to 11 years after wildfire) in Catalonia (Spain), which were sampled between 2006 and 2013. Generalized linear mixed models (GLMMs) showed that plant cover was affected by time since fire, aridity and forest management. However, only the highest vegetation height layer (>100 cm) recovered slower in arid areas after fire. Time since fire positively influenced bird species richness and the relative abundance of the four focal species. The post-fire recovery of Melodious (Hippolais polyglotta) and Subalpine warblers (Sylvia cantillans) was hampered by aridity. Although this was not demonstrated for Dartford (S. undata) and Sardinian warblers (S. melanocephala), their occurrence was low in the driest areas during the first three years after fire. Overall, this study suggests that future increases in aridity can affect plant regeneration after fire and slow down the recovery of animal populations that depend on understorey and shrublands. Given the recently highlighted increases in aridity and fire frequency in Mediterranean-climate regions, improved knowledge on how aridity affects ecological succession is especially necessary.
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Plant density affects measures of biodiversity effects
Czech Academy of Sciences Publication Activity Database
Stachová, T.; Fibich, P.; Lepš, Jan
2013-01-01
Roč. 6, č. 1 (2013), s. 1-11 ISSN 1752-9921 R&D Projects: GA ČR GD206/08/H044 Grant - others:GA JU(CZ) 138/2010/P Institutional support: RVO:60077344 Keywords : biodiversity effects * plant density * constant final yield Subject RIV: EH - Ecology, Behaviour Impact factor: 2.284, year: 2013 http://jpe.oxfordjournals.org/content/early/2012/04/27/jpe.rts015.full.pdf+html
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Directory of Open Access Journals (Sweden)
Ahmed Elhady
2018-06-01
Full Text Available Plant-parasitic nematodes cause considerable damage to crop plants. The rhizosphere microbiome can affect invasion and reproductive success of plant-parasitic nematodes, thus affecting plant damage. In this study, we investigated how the transplanted rhizosphere microbiome from different crops affect plant-parasitic nematodes on soybean or tomato, and whether the plant’s own microbiome from the rhizosphere protects it better than the microbiome from fallow soil. Soybean plants growing in sterilized substrate were inoculated with the microbiome extracted from the rhizosphere of soybean, maize, or tomato. Controls were inoculated with extracts from bulk soil, or not inoculated. After the microbiome was established, the root lesion nematode Pratylenchus penetrans was added. Root invasion of P. penetrans was significantly reduced on soybean plants inoculated with the microbiome from maize or soybean compared to tomato or bulk soil, or the uninoculated control. In the analogous experiment with tomato plants inoculated with either P. penetrans or the root knot nematode Meloidogyne incognita, the rhizosphere microbiomes of maize and tomato reduced root invasion by P. penetrans and M. incognita compared to microbiomes from soybean or bulk soil. Reproduction of M. incognita on tomato followed the same trend, and it was best suppressed by the tomato rhizosphere microbiome. In split-root experiments with soybean and tomato plants, a systemic effect of the inoculated rhizosphere microbiomes on root invasion of P. penetrans was shown. Furthermore, some transplanted microbiomes slightly enhanced plant growth compared to uninoculated plants. The microbiomes from maize rhizosphere and bulk soil increased the fresh weights of roots and shoots of soybean plants, and microbiomes from soybean rhizosphere and bulk soil increased the fresh weights of roots and shoots of tomato plants. Nematode invasion did not affect plant growth in these short-term experiments. In
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A comparison of ground-based methods for estimating canopy closure for use in phenology research
Smith, AM; Ramsay, PM
2018-01-01
Abstract Climate change is influencing tree phenology, causing earlier and more prolonged canopy closure in temperate forests. Canopy closure is closely associated with understorey light, so shifts in its timing have wide-reaching consequences for ecological processes in the understorey. Widespread monitoring of forest canopies through time is needed to understand changes in light availability during spring in particular. Canopy openness, derived from hemispherical photography, has frequently...
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Chemical signaling between plants and plant-pathogenic bacteria.
Venturi, Vittorio; Fuqua, Clay
2013-01-01
Studies of chemical signaling between plants and bacteria in the past have been largely confined to two models: the rhizobial-legume symbiotic association and pathogenesis between agrobacteria and their host plants. Recent studies are beginning to provide evidence that many plant-associated bacteria undergo chemical signaling with the plant host via low-molecular-weight compounds. Plant-produced compounds interact with bacterial regulatory proteins that then affect gene expression. Similarly, bacterial quorum-sensing signals result in a range of functional responses in plants. This review attempts to highlight current knowledge in chemical signaling that takes place between pathogenic bacteria and plants. This chemical communication between plant and bacteria, also referred to as interkingdom signaling, will likely become a major research field in the future, as it allows the design of specific strategies to create plants that are resistant to plant pathogens.
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Maximizing plant density affects broccoli yield and quality
Increased demand for fresh market bunch broccoli (Brassica oleracea L. var. italica) has led to increased production along the United States east coast. Maximizing broccoli yields is a primary concern for quickly expanding southeastern commercial markets. This broccoli plant density study was carr...
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Bárcenas-Moreno, Gema; Zavala, Lorena; Jordan, Antonio; Bååth, Erland; Mataix-Beneyto, Jorge
2013-04-01
Plant communities can play an important role in fire severity and post-fire ecosystem recovery due to their role as combustible and different plant-soil microorganisms interactions. Possible differences induced by plant and microorganisms response after fire could affect the general ecosystem short and long-term response and its sustainability. The main objective of this work was the evaluation of the effect of wildfire on soil microbial abundance, activity and diversity in two different plant communities associated to different altitudes in Sierra Nevada National Park (Granada, Spain). Samples were collected in two areas located on the Sierra Nevada Mountain between 1700 and 2000 m above sea level which were affected by a large wildfire in 2005. Two samplings were carried out 8 and 20 months after fire and samples were collected in both burned and unburned (control) zones in each plant community area. Area A is located at 1700m and it is formed by Quercus rotundifolia forest while area B is located at 2000 m altitude and is composed of alpine vegetation formed by creeping bearing shrubs. Microbial biomass measured by Fumigation-Extraction method followed the same trend in both areas showing slight and no significant differences between burned and unburned area during the study period while viable and cultivable bacteria abundance were markedly higher in fire affected samples than in the control ones in both samplings. Viable and cultivable filamentous fungi had different behavior depending of plant vegetation community studied showing no differences between burned and unburned area in area A while was significantly higher in burned samples than in the control ones in area B. Microbial activity monitoring with soil microbial respiration appears to had been affected immediately after fire since microbial respiration was lower in burned samples from area A than in unburned one only 8 months after fire and no significant differences were observed between burned and
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Ponzio, C.A.M.; Weldegergis, B.T.; Dicke, M.; Gols, R.
2016-01-01
The three data sheets show the data for the three types of comparisons that were made: (1) wasp choice when offered acaterpillar infested plant and a caterpillar + pathogen infected plant (2) wasp choice when offered a healthy plant against a singleattacker infected/infected plant and (3) wasp
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Yokawa, K; Kagenishi, T; Pavlovic, A; Gall, S; Weiland, M; Mancuso, S; Baluška, F
2017-12-11
Anaesthesia for medical purposes was introduced in the 19th century. However, the physiological mode of anaesthetic drug actions on the nervous system remains unclear. One of the remaining questions is how these different compounds, with no structural similarities and even chemically inert elements such as the noble gas xenon, act as anaesthetic agents inducing loss of consciousness. The main goal here was to determine if anaesthetics affect the same or similar processes in plants as in animals and humans. A single-lens reflex camera was used to follow organ movements in plants before, during and after recovery from exposure to diverse anaesthetics. Confocal microscopy was used to analyse endocytic vesicle trafficking. Electrical signals were recorded using a surface AgCl electrode. Mimosa leaves, pea tendrils, Venus flytraps and sundew traps all lost both their autonomous and touch-induced movements after exposure to anaesthetics. In Venus flytrap, this was shown to be due to the loss of action potentials under diethyl ether anaesthesia. The same concentration of diethyl ether immobilized pea tendrils. Anaesthetics also impeded seed germination and chlorophyll accumulation in cress seedlings. Endocytic vesicle recycling and reactive oxygen species (ROS) balance, as observed in intact Arabidopsis root apex cells, were also affected by all anaesthetics tested. Plants are sensitive to several anaesthetics that have no structural similarities. As in animals and humans, anaesthetics used at appropriate concentrations block action potentials and immobilize organs via effects on action potentials, endocytic vesicle recycling and ROS homeostasis. Plants emerge as ideal model objects to study general questions related to anaesthesia, as well as to serve as a suitable test system for human anaesthesia. © The Authors 2017. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
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Lerm, Stephanie; Westphal, Anke; Miethling-Graff, Rona; Alawi, Mashal; Seibt, Andrea; Wolfgramm, Markus; Würdemann, Hilke
2013-04-01
The microbial composition in fluids of a deep saline geothermal used aquifer in the North German Basin was characterized over a period of five years. The genetic fingerprinting techniques PCR-SSCP and PCR-DGGE revealed distinct microbial communities in fluids produced from the cold and warm side of the aquifer. Direct cell counting and quantification of 16S rRNA genes and dissimilatory sulfite reductase (dsrA) genes by real-time PCR proved different population sizes in fluids, showing higher abundance of Bacteria and sulfate reducing bacteria (SRB) in cold fluids compared to warm fluids. Predominating SRB in the cold well probably accounted for corrosion damage to the submersible well pump, and iron sulfide precipitates in the near wellbore area and topside facility filters. This corresponded to a lower sulfate content in fluids produced from the cold well as well as higher content of hydrogen gas that was probably released from corrosion, and maybe favoured growth of hydrogenotrophic SRB. Plant downtime significantly influenced the microbial biocenosis in fluids. Samples taken after plant restart gave indications about the processes occurring downhole during those phases. High DNA concentrations in fluids at the beginning of the restart process with a decreasing trend over time indicated a higher abundance of microbes during plant downtime compared to regular plant operation. It is likely that a gradual drop in temperature as well as stagnant conditions favoured the growth of microbes and maturation of biofilms at the casing and in pores of the reservoir rock in the near wellbore area. Furthermore, it became obvious that the microorganisms were more associated to particles then free-living. This study reflects the high influence of microbial populations for geothermal plant operation, because microbiologically induced precipitative and corrosive processes adversely affect plant reliability. Those processes may favourably occur during plant downtime due to enhanced
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Will global warming affect soil-to-plant transfer of radionuclides?
International Nuclear Information System (INIS)
Dowdall, M.; Standring, W.; Shaw, G.; Strand, P.
2008-01-01
Recent assessments of global climate/environmental change are reaching a consensus that global climate change is occurring but there is significant uncertainty over the likely magnitude of this change and its impacts. There is little doubt that all aspects of the natural environment will be impacted to some degree. Soil-to-plant transfer of radionuclides has long been a significant topic in radioecology, both for the protection of humans and the environment from the effects of ionising radiation. Even after five decades of research considerable uncertainty exists as to the interplay of key environmental processes in controlling soil-plant transfer. As many of these processes are, to a lesser or greater extent, climate-dependent, it can be argued that climate/environmental change will impact soil-to-plant transfer of radionuclides and subsequent transfers in specific environments. This discussion attempts to highlight the possible role of climatic and climate-dependent variables in soil-to-plant transfer processes within the overall predictions of climate/environmental change. The work is speculative, and intended to stimulate debate on a theme that radioecology has either ignored or avoided in recent years
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El-Keblawy, Ali; El-Sheikh, Mohamed
2017-04-01
Grazing and drought can adversely affect the ecology and management of rangeland ecosystems. Several management actions have been applied to restore species diversity and community structure in degraded rangelands of the unpredictable arid environment. Protection from grazing is considered as a proper approach for restoration of degraded rangelands, but this depends on substrate type and sometime is hindered with water deficiency (drought). In this study, the effect of protection from grazing animals on species diversity and plant community structure was assessed after a dry and wet periods in both sandy and gravelly substrates in the Dubai Desert Conservation reserve (DDCR), United Arab Emirates. Two sites were selected during November 2012 on the two substrate types (fixed sandy flat and gravel plain) in the arid DDCR. An enclosure was established in each site. Plant community attributes (plant cover, density, frequency, species composition, and diversity indices) were assessed in a number of permanent plots laid inside and outside each enclosure during November 2012, April 2014 and April 2016. The results showed that protection improved clay content, but decreased the organic matters. Interestingly, the protection reduced the concentrations of most estimated nutrients, which could be attributed to the high turnover rate of nutrients associated grazing and low decomposition of accumulated dry plants of non-protected sites. Protection significantly increased all plant community attributes, but the only significant effect was for plant density. Plant density was almost twice greater inside than outside the enclosures. During the dry period, protection resulted in significantly greater deterioration in cover, density and all diversity indices in gravel, compared to sandy sites. Most of the grasses and shrubby plants had died in the gravel plains. However, plant community of the gravel plains was significantly restored after receiving considerable rainfalls. The
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How light competition between plants affects their response to climate change.
van Loon, Marloes P; Schieving, Feike; Rietkerk, Max; Dekker, Stefan C; Sterck, Frank; Anten, Niels P R
2014-09-01
How plants respond to climate change is of major concern, as plants will strongly impact future ecosystem functioning, food production and climate. Here, we investigated how vegetation structure and functioning may be influenced by predicted increases in annual temperatures and atmospheric CO2 concentration, and modeled the extent to which local plant-plant interactions may modify these effects. A canopy model was developed, which calculates photosynthesis as a function of light, nitrogen, temperature, CO2 and water availability, and considers different degrees of light competition between neighboring plants through canopy mixing; soybean (Glycine max) was used as a reference system. The model predicts increased net photosynthesis and reduced stomatal conductance and transpiration under atmospheric CO2 increase. When CO2 elevation is combined with warming, photosynthesis is increased more, but transpiration is reduced less. Intriguingly, when competition is considered, the optimal response shifts to producing larger leaf areas, but with lower stomatal conductance and associated vegetation transpiration than when competition is not considered. Furthermore, only when competition is considered are the predicted effects of elevated CO2 on leaf area index (LAI) well within the range of observed effects obtained by Free air CO2 enrichment (FACE) experiments. Together, our results illustrate how competition between plants may modify vegetation responses to climate change. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.
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Jing, Jingying; Bezemer, T. Martijn; Van der Putten, Wim H.
2015-01-01
Plant–soil feedback can affect plants that belong to the same (intraspecific feedback) or different species (interspecific feedback). However, little is known about how intra- and interspecific plant–soil feedbacks influence interspecific plant competition. Here, we used plants and soil from early-stage ex-arable fields to examine how intra- and interspecific plant–soil feedbacks affect the performance of 10 conditioning species and the focal species, Jacobaea vulgaris. Plants were grown alon...
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How light competition between plants affects trait optimization and vegetation-atmosphere feedbacks
van Loon, M.P.
2016-01-01
How plants respond to climate change is of major concern, as plants will strongly impact future ecosystem functioning, food production and climate. Competition between plants for resources is an important selective force. As a result competition through natural selection determines vegetation
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Plant stress signalling: understanding and exploiting plant-plant interactions.
Pickett, J A; Rasmussen, H B; Woodcock, C M; Matthes, M; Napier, J A
2003-02-01
When plants are attacked by insects, volatile chemical signals can be released, not only from the damaged parts, but also systemically from other parts of the plant and this continues after cessation of feeding by the insect. These signals are perceived by olfactory sensory mechanisms in both the herbivorous insects and their parasites. Molecular structures involved can be characterized by means of electrophysiological assays, using the insect sensory system linked to chemical analysis. Evidence is mounting that such signals can also affect neighbouring intact plants, which initiate defence by the induction of further signalling systems, such as those that increase parasitoid foraging. Furthermore, insect electrophysiology can be used in the identification of plant compounds having effects on the plants themselves. It has been found recently that certain plants can release stress signals even when undamaged, and that these can cause defence responses in intact plants. These discoveries provide the basis for new crop protection strategies, that are either delivered by genetic modification of plants or by conventionally produced plants to which the signal is externally applied. Delivery can also be made by means of mixed seed strategies in which the provoking and recipient plants are grown together. Related signalling discoveries within the rhizosphere seem set to extend these approaches into new ways of controlling weeds, by exploiting the elusive potential of allelopathy, but through signalling rather than by direct physiological effects.
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Pasture shade and farm management effects on cow productivity in the tropics
Ainsworth, Justin A.W.; Moe, Stein R.; Skarpe, Christina
2012-01-01
This is the postprint version of the article. The published article can be located at the publisher's webpage Shade, provided by trees within pastures, can affect cattle productivity through mitigating heat stress and by altering understorey pasture growth and cattle behaviour. Models for daily milk yield and body condition were used to evaluate the effect of pasture shade on dual purpose cow productivity within a silvopastoral system in a dry tropical province of Nicaragua. Daily milk yie...
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Directory of Open Access Journals (Sweden)
Yang Haishui
2012-04-01
Full Text Available Abstract Background Arbuscular mycorrhizal fungi (AMF can form obligate symbioses with the vast majority of land plants, and AMF distribution patterns have received increasing attention from researchers. At the local scale, the distribution of AMF is well documented. Studies at large scales, however, are limited because intensive sampling is difficult. Here, we used ITS rDNA sequence metadata obtained from public databases to study the distribution of AMF at continental and global scales. We also used these sequence metadata to investigate whether host plant is the main factor that affects the distribution of AMF at large scales. Results We defined 305 ITS virtual taxa (ITS-VTs among all sequences of the Glomeromycota by using a comprehensive maximum likelihood phylogenetic analysis. Each host taxonomic order averaged about 53% specific ITS-VTs, and approximately 60% of the ITS-VTs were host specific. Those ITS-VTs with wide host range showed wide geographic distribution. Most ITS-VTs occurred in only one type of host functional group. The distributions of most ITS-VTs were limited across ecosystem, across continent, across biogeographical realm, and across climatic zone. Non-metric multidimensional scaling analysis (NMDS showed that AMF community composition differed among functional groups of hosts, and among ecosystem, continent, biogeographical realm, and climatic zone. The Mantel test showed that AMF community composition was significantly correlated with plant community composition among ecosystem, among continent, among biogeographical realm, and among climatic zone. The structural equation modeling (SEM showed that the effects of ecosystem, continent, biogeographical realm, and climatic zone were mainly indirect on AMF distribution, but plant had strongly direct effects on AMF. Conclusion The distribution of AMF as indicated by ITS rDNA sequences showed a pattern of high endemism at large scales. This pattern indicates high specificity
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Yang, Haishui; Zang, Yanyan; Yuan, Yongge; Tang, Jianjun; Chen, Xin
2012-04-12
Arbuscular mycorrhizal fungi (AMF) can form obligate symbioses with the vast majority of land plants, and AMF distribution patterns have received increasing attention from researchers. At the local scale, the distribution of AMF is well documented. Studies at large scales, however, are limited because intensive sampling is difficult. Here, we used ITS rDNA sequence metadata obtained from public databases to study the distribution of AMF at continental and global scales. We also used these sequence metadata to investigate whether host plant is the main factor that affects the distribution of AMF at large scales. We defined 305 ITS virtual taxa (ITS-VTs) among all sequences of the Glomeromycota by using a comprehensive maximum likelihood phylogenetic analysis. Each host taxonomic order averaged about 53% specific ITS-VTs, and approximately 60% of the ITS-VTs were host specific. Those ITS-VTs with wide host range showed wide geographic distribution. Most ITS-VTs occurred in only one type of host functional group. The distributions of most ITS-VTs were limited across ecosystem, across continent, across biogeographical realm, and across climatic zone. Non-metric multidimensional scaling analysis (NMDS) showed that AMF community composition differed among functional groups of hosts, and among ecosystem, continent, biogeographical realm, and climatic zone. The Mantel test showed that AMF community composition was significantly correlated with plant community composition among ecosystem, among continent, among biogeographical realm, and among climatic zone. The structural equation modeling (SEM) showed that the effects of ecosystem, continent, biogeographical realm, and climatic zone were mainly indirect on AMF distribution, but plant had strongly direct effects on AMF. The distribution of AMF as indicated by ITS rDNA sequences showed a pattern of high endemism at large scales. This pattern indicates high specificity of AMF for host at different scales (plant taxonomic
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Unpreferred plants affect patch choice and spatial distribution of European brown hares
Kuijper, D.P.J.; Bakker, J.P.
2008-01-01
Many herbivore species prefer to forage on patches of intermediate biomass. Plant quality and forage efficiency are predicted to decrease with increasing plant standing crop which explains the lower preference of the herbivore. However, often is ignored that on the long-term, plant species
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A nuclear power plant status monitor
International Nuclear Information System (INIS)
Chu, B.B.; Conradi, L.L.; Weinzimmer, F.
1986-01-01
Power plant operation requires decisions that can affect both the availability of the plant and its compliance with operating guidelines. Taking equipment out of service may affect the ability of the plant to produce power at a certain power level and may also affect the status of the plant with regard to technical specifications. Keeping the plant at a high as possible production level and remaining in compliance with the limiting conditions for operation (LCOs) can dictate a variety of plant operation and maintenance actions and responses. Required actions and responses depend on the actual operational status of a nuclear plant and its attendant systems, trains, and components which is a dynamic situation. This paper discusses an Electric Power Research Institute (EPRI) Research Project, RP 2508, the objective of which is to combine the key features of plant information management systems with systems reliability analysis techniques in order to assist nuclear power plant personnel to perform their functions more efficiently and effectively. An overview of the EPRI Research Project is provided along with a detailed discussion of the design and operation of the PSM portion of the project
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Klabi, Rim; Bell, Terrence H; Hamel, Chantal; Iwaasa, Alan; Schellenberg, Mike; Raies, Aly; St-Arnaud, Marc
2015-01-01
Adding inorganic P- and N-fixing legumes to semi-arid grasslands can increase forage yield, but soil nutrient concentrations and plant cover may also interact to modify soil fungal populations, impacting short- and long-term forage production. We tested the effect of plant assemblage (seven native grasses, seven native grasses + the domesticated N-fixing legume Medicago sativa, seven native grasses + the native N-fixing legume Dalea purpurea or the introduced grass Bromus biebersteinii + M. sativa) and soil P concentration (addition of 0 or 200 P2O5 kg ha(-1) at sowing) on the diversity and community structure of arbuscular mycorrhizal (AM) fungi and total fungi over two consecutive years, using 454-pyrosequencing of 18S rDNA and ITS amplicons. Treatment effects were stronger in the wet year (2008) than the dry year (2009). The presence of an N-fixing legume with native grasses generally increased AM fungal diversity, while the interaction between soil P concentration and plant assemblage modified total fungal community structure in 2008. Excluding interannual variations, which are likely driven by moisture and plant productivity, AM fungal communities in semi-arid grasslands appear to be primarily affected by plant assemblage composition, while the composition of other fungi is more closely linked to soil P. © FEMS 2014. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
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UV-B radiation affects plant volatile emissions and shade avoidance responses
Gankema, P.
2015-01-01
Plants detect and integrate an assortment of signals from their environment, and use these signals to maximise their performance by adjusting their growth and development as well as their secondary metabolite production. In this thesis, we investigated how plants integrate visual and olfactory
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How light competition between plants affects their response to climate change
Loon, van M.P.; Schieving, F.; Rietkerk, M.; Dekker, S.C.; Sterck, F.J.; Anten, N.P.R.
2014-01-01
How plants respond to climate change is of major concern, as plants will strongly impact future ecosystem functioning, food production and climate. Here, we investigated how vegetation structure and functioning may be influenced by predicted increases in annual temperatures and atmospheric CO2
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Directory of Open Access Journals (Sweden)
Leon Hartwell Allen, Jr.
2018-04-01
Full Text Available A study was conducted in four compartments of a polycarbonate greenhouse at Gainesville, FL, USA to investigate how a soybean (Glycine max L. Merr. cultivar, Maverick (maturity group III, indeterminate, responded to three elevated temperatures, ELT, (day/night of 34/26 °C, 38/30 °C, and 42/34 °C in comparison to a control growth temperature (30/22 °C. Carbon dioxide (CO2 concentration was maintained at 700 μmol mol−1 in each compartment by a processor controlled air-sampling and CO2-injection system. Three sequential experiments were conducted at different times of year (summer, autumn, and early spring to investigate the effect of intensity, timing, and duration of ELT on soybean node number, internode elongation, mainstem length, and number of pods set per plant. At the control temperature, the soybean plants grown in the polycarbonate greenhouse were taller than field-grown plants. When plants were grown under continuous ELT applied soon after sowing or at initial flowering, the number of nodes increased with increasing ELT intensity, whereas the length of individual internodes decreased. When ELT treatment was applied during the beginning of flowering stage (R1–R2 or earlier, more nodes were produced and the length of affected internodes was decreased. When the ELT was imposed later at reproductive stage R5+ just before the beginning of seed filling, effects on node numbers and internode lengths were negligible. Short-term (10-day duration of ELT applied at four stages from V3 to R5+ did not significantly affect final mean numbers of nodes or mean mainstem lengths. Possible mechanisms of elevated temperature effects on soybean internode elongation and node number (internode number are discussed. Total pod numbers per plant increased linearly with mainstem node numbers and mainstem length. Furthermore, total pod numbers per plant were greatest at 34/26 °C rather than at the control temperature of 30/22 °C (and
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Affecting microclimate in surroundings of nuclear power plants
International Nuclear Information System (INIS)
Skulec, S.; Janiskova, M.
1990-01-01
The influence of nuclear power plants on regional climate was observed and studied. Cooling towers emit waste heat and humidity and the resulting primary effects consist of local changes in air temperature and humidity. Secondary effects could be changes in all meteorologic parameters depending on the primary changes. A series of mathematical models was created to evaluate long-term climate changes depending on the power range, type of cooling, regional climate, etc. The first generation of the models, finished in 1986, was based on conservative estimates of the effects observed. The second generation was developed between 1986 and 1988 and should provide more realistic values. Simulated results were compared with the observed data. Although the verification of the models has not yet been finished, the agreement between the simulated results and the observed values seems to be good. The results show that the influence of nuclear power plants on the climate is almost not observable and cannot be registered by usual measuring methods. (J.J.). 4 figs., 2 tabs., 6 refs
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Fréjaville , T.; Curt , T.; Carcaillet , C.
2016-01-01
International audience; Little is known about the understorey flammability of European mountain forests. The aim of this study was to determine the relative effects of climate, vegetation structure and composition on the fuel-driven variation in fire spread and intensity. Fire spread and intensity were simulated under constant moisture and weather conditions for a wide range of understorey fuel parameters measured in the litter, grass and shrub layers. Simulation outputs were used to compare ...
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Directory of Open Access Journals (Sweden)
Nico Eisenhauer
2011-01-01
Full Text Available One of the most significant consequences of contemporary global change is the rapid decline of biodiversity in many ecosystems. Knowledge of the consequences of biodiversity loss in terrestrial ecosystems is largely restricted to single ecosystem functions. Impacts of key plant functional groups on soil biota are considered to be more important than those of plant diversity; however, current knowledge mainly relies on short-term experiments.We studied changes in the impacts of plant diversity and presence of key functional groups on soil biota by investigating the performance of soil microorganisms and soil fauna two, four and six years after the establishment of model grasslands. The results indicate that temporal changes of plant community effects depend on the trophic affiliation of soil animals: plant diversity effects on decomposers only occurred after six years, changed little in herbivores, but occurred in predators after two years. The results suggest that plant diversity, in terms of species and functional group richness, is the most important plant community property affecting soil biota, exceeding the relevance of plant above- and belowground productivity and the presence of key plant functional groups, i.e. grasses and legumes, with the relevance of the latter decreasing in time.Plant diversity effects on biota are not only due to the presence of key plant functional groups or plant productivity highlighting the importance of diverse and high-quality plant derived resources, and supporting the validity of the singular hypothesis for soil biota. Our results demonstrate that in the long term plant diversity essentially drives the performance of soil biota questioning the paradigm that belowground communities are not affected by plant diversity and reinforcing the importance of biodiversity for ecosystem functioning.
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Mao, L.; Zhang, L.; Zhao, X.; Liu, S.; Werf, van der W.; Zhang, S.; Spiertz, J.H.J.; Li, Z.
2014-01-01
Modern cotton cultivation requires high plant densities and compact plants. Here we study planting density and growth regulator effects on plant structure and production of cotton when the cotton is grown in a relay intercrop with wheat, a cultivation system that is widespread in China. Field
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Volatile communication between plants that affects herbivory: a meta-analysis.
Karban, Richard; Yang, Louie H; Edwards, Kyle F
2014-01-01
Volatile communication between plants causing enhanced defence has been controversial. Early studies were not replicated, and influential reviews questioned the validity of the phenomenon. We collected 48 well-replicated studies and found overall support for the hypothesis that resistance increased for individuals with damaged neighbours. Laboratory or greenhouse studies and those conducted on agricultural crops showed stronger induced resistance than field studies on undomesticated species, presumably because other variation had been reduced. A cumulative analysis revealed that early, non-replicated studies were more variable and showed less evidence for communication. Effects of habitat and plant growth form were undetectable. In most cases, the mechanisms of resistance and alternative hypotheses were not considered. There was no indication that some response variables were more likely to produce large effects. These results indicate that plants of diverse taxonomic affinities and ecological conditions become more resistant to herbivores when exposed to volatiles from damaged neighbours. © 2013 John Wiley & Sons Ltd/CNRS.
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Kabiri, S.; Rodenburg, J.; Ast, van A.; Bastiaans, L.
2017-01-01
The rain-fed lowland rice weed Rhamphicarpa fistulosa (Rice Vampireweed) is a facultative root parasitic plant. Growth and reproduction of R. fistulosa benefit considerably from parasitism, but how this affects the host plant is not well established. We determined accumulation and partitioning of
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Growth and nutrient uptake of maize plants as affected by elemental ...
African Journals Online (AJOL)
Jane
2011-10-05
Oct 5, 2011 ... and Cu, thus characterized as deficient in these micro nutrients. Nitrogen, phosphorus (P) and ... play an important role in the protection of plants against nutrient stress and pests and synthesis of vitamins ..... Brassica oleracea is controlled by the expression and the activity of sulphate transporter. Plant Biol.
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Hypolite, Christine Collins
The purpose of this research was to determine how an inquiry-based, whole-plant instructional strategy would affect preservice elementary teachers' understanding of plant science principles. This study probed: what preservice teachers know about plant biology concepts before and after instruction, their views of the interrelatedness of plant parts and the environment, how growing a plant affects preservice teachers' understanding, and which types of activity-rich plant themes studies, if any, affect preservice elementary teachers' understandings. The participants in the study were enrolled in two elementary science methods class sections at a state university. Each group was administered a preinstructional test at the beginning of the study. The treatment group participated in inquiry-based activities related to the Principles of Plant Biology (American Society of Plant Biologists, 2001), while the comparison group studied those same concepts through traditional instructional methods. A focus group was formed from the treatment group to participate in co-concept mapping sessions. The participants' understandings were assessed through artifacts from activities, a comparison of pre- and postinstructional tests, and the concept maps generated by the focus group. Results of the research indicated that the whole-plant, inquiry-based instructional strategy can be applied to teach preservice elementary teachers plant biology while modeling the human constructivist approach. The results further indicated that this approach enhanced their understanding of plant science content knowledge, as well as pedagogical knowledge. The results also showed that a whole-plant approach to teaching plant science concepts is an instructional strategy that is feasible for the elementary school. The theoretical framework for this study was Human Constructivist learning theory (Mintzes & Wandersee, 1998). The content knowledge and instructional strategy was informed by the Principles of Plant
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Jassey, Vincent E J; Chiapusio, Geneviève; Binet, Philippe; Buttler, Alexandre; Laggoun-Défarge, Fatima; Delarue, Frédéric; Bernard, Nadine; Mitchell, Edward A D; Toussaint, Marie-Laure; Francez, André-Jean; Gilbert, Daniel
2013-03-01
Peatlands contain approximately one third of all soil organic carbon (SOC). Warming can alter above- and belowground linkages that regulate soil organic carbon dynamics and C-balance in peatlands. Here we examine the multiyear impact of in situ experimental warming on the microbial food web, vegetation, and their feedbacks with soil chemistry. We provide evidence of both positive and negative impacts of warming on specific microbial functional groups, leading to destabilization of the microbial food web. We observed a strong reduction (70%) in the biomass of top-predators (testate amoebae) in warmed plots. Such a loss caused a shortening of microbial food chains, which in turn stimulated microbial activity, leading to slight increases in levels of nutrients and labile C in water. We further show that warming altered the regulatory role of Sphagnum-polyphenols on microbial community structure with a potential inhibition of top predators. In addition, warming caused a decrease in Sphagnum cover and an increase in vascular plant cover. Using structural equation modelling, we show that changes in the microbial food web affected the relationships between plants, soil water chemistry, and microbial communities. These results suggest that warming will destabilize C and nutrient recycling of peatlands via changes in above- and belowground linkages, and therefore, the microbial food web associated with mosses will feedback positively to global warming by destabilizing the carbon cycle. This study confirms that microbial food webs thus constitute a key element in the functioning of peatland ecosystems. Their study can help understand how mosses, as ecosystem engineers, tightly regulate biogeochemical cycling and climate feedback in peatlands. © 2012 Blackwell Publishing Ltd.
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Importance of biotic and abiotic components in feedback between plants and soil
Hanzelková, Věra
2017-01-01
The plant-soil feedback affects the forming of a plant community. Plants affect their own species as well as other species. The plant-soil feedback can be both positive and negative. Plants affect soil, change its properties, and the soil affects the plants reciprocally. Soil components can be divided into biotic and abiotic ones. The abiotic component is represented by physical and chemical properties of the soil. The main properties are the soil structure, the soil moisture, the soil temper...
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Energy Technology Data Exchange (ETDEWEB)
Guillitte, O. (Unite de Radioecologie, Faculte des Sciences Agronomiques, Gembloux (Belgium)); Melin, J.; Wallberg, L. (Swedish Radiation Protection Institute, Stockholm (Sweden))
1994-10-14
In an attempt to understand the mechanisms governing the transfer and retention of radiocaesium in the understorey vegetation, 39 macromycetes species and 33 plant species, together with humus samples, were systematically collected from the undercover vegetation in a boreal coniferous forest. The results indicate that the main factors determining interspecific differences in contamination level are the rooting depth in plants, the depth of mycelium in fungi, and the ecophysiological behaviour of fungi, mycotrophism or plant parasitism. A comparison between the investigated species and the same species growing in similar ecosystems, albeit under different climatic conditions, resulted in an almost identical ranking in terms of radiocaesium contamination levels; the contamination ratios between species were also relatively constant. From an experiment involving humus samples, it was shown that up to 40% of the radiocaesium could be retained by the microflora, particularly by mycelia.
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Methyl salicylate production in tomato affects biotic interactions.
Ament, Kai; Krasikov, Vladimir; Allmann, Silke; Rep, Martijn; Takken, Frank L W; Schuurink, Robert C
2010-04-01
The role of methyl salicylate (MeSA) production was studied in indirect and direct defence responses of tomato (Solanum lycopersicum) to the spider mite Tetranychus urticae and the root-invading fungus Fusarium oxysporum f. sp. lycopersici, respectively. To this end, we silenced the tomato gene encoding salicylic acid methyl transferase (SAMT). Silencing of SAMT led to a major reduction in SAMT expression and MeSA emission upon herbivory by spider mites, without affecting the induced emission of other volatiles (terpenoids). The predatory mite Phytoseiulus persimilis, which preys on T. urticae, could not discriminate between infested and non-infested SAMT-silenced lines, as it could for wild-type tomato plants. Moreover, when given the choice between infested SAMT-silenced and infested wild-type plants, they preferred the latter. These findings are supportive of a major role for MeSA in this indirect defence response of tomato. SAMT-silenced tomato plants were less susceptible to a virulent strain of F. oxysporum f. sp. lycopersici, indicating that the direct defense responses in the roots are also affected in these plants. Our studies show that the conversion of SA to MeSA can affect both direct and indirect plant defence responses.
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da Silva, André Costa; de Oliveira Silva, Franklin Magnum; Milagre, Jocimar Caiafa; Omena-Garcia, Rebeca Patricia; Abreu, Mário Castro; Mafia, Reginaldo Gonçalves; Nunes-Nesi, Adriano; Alfenas, Acelino Couto
2018-02-01
Ceratocystis wilt, caused by Ceratocystis fimbriata, is currently one of the most important disease in eucalypt plantations. Plants infected by C. fimbriata have lower volumetric growth, lower pulp yields and reduced timber values. The physiological bases of infection induced by this pathogen in eucalypt plant are not known. Therefore, this study aims to assess the physiological and metabolic changes in eucalypt clones that are resistant and susceptible to C. fimbriata. Once, we evaluated in detail their leaf gas exchange, chlorophyll a fluorescence, water potential, metabolite profiling and growth-related parameters. When inoculated, the susceptible clone displayed reduced water potential, CO 2 assimilation rate, stomatal conductance, transpiration rate, photochemical quenching coefficient, electron transport rate, and root biomass. Inoculated resistant and susceptible clones both presented higher respiration rates than healthy plants. Many compounds of primary and secondary metabolism were significantly altered after fungal infection in both clones. These results suggest that, C. fimbriata interferes in the primary and secondary metabolism of plants that may be linked to the induction of defense mechanisms and that, due to water restrictions caused by the fungus in susceptible plants, there is a partial closure of the stomata to prevent water loss and a consequent reduction in photosynthesis and the transpiration rate, which in turn, leads to a decrease in the plant's growth-related. These results combined, allowed for a better understanding of the physiological and metabolic changes following the infectious process of C. fimbriata, which limit eucalypt plant growth. Copyright © 2017 Elsevier Masson SAS. All rights reserved.
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Energy Technology Data Exchange (ETDEWEB)
Tognoni, F; Halevy, A H; Wittwer, S H
1967-01-01
Bean and tomato plants were grown in solution culture root media containing pre-determined concentrations of gibberellin A/sub 3/ (GA), 1-naphthalene-acetic acid (NAA), N/sup 6/-benzyladenine (BA), (2-chloroethyl)trimethylammonium chloride (CCC), and at atmospheric levels of 300 and 1000 ppm of CO/sub 2/. Net assimilation rates (NAR), relative growth rates (RGR), leaf area ratios (LAR), root to top dry weight ratios (R/T) and changes in dry weight, size, and form of each organ were recorded. Gibberellin had no effect on RGR of either plant species but increased the NAR of tomatoes at 1000 ppm CO/sub 2/. Total dry weight was only slightly affected by GA but root growth and R/T were markedly depressed. CCC had no effect on NAR, but decreased RGR and LAR. Root growth of beans and R/T in both plants were promoted by CCC. NAR and RGR were strongly inhibited by BA and NAA. Inhibition of stem and leaf growth by CCC and NAA was greater than that for roots; thus, R/T ratios were increased. Root branching was promoted by NAA. High (1000 ppm), compared to the low (300 ppm), atmospheric levels of CO/sub 2/ generally promoted root growth and produced an increase in the R/T, both in the absence and presence of chemical treatment. The multiplicity of effects of the root-absorbed chemical growth substances and CO/sub 2/ on growth and photosynthesis is discussed.
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Pilling, J; Willmitzer, L; Bücking, H; Fisahn, J
2004-05-01
Two pectin methyl esterases (PMEs; EC 3.1.1.11) from Solanum tuberosum were isolated and their expression characterised. One partial clone ( pest1) was expressed in leaves and fruit tissue, while pest2 was a functional full-length clone and was expressed ubiquitously, with a preference for aerial organs. Potato plants were transformed with a chimeric antisense construct that was designed to simultaneously inhibit pest1 and pest2 transcript accumulation; however, reduction of mRNA levels was confined to pest2. The decrease in pest2 transcript was accompanied by up to 50% inhibition of total PME activity, which was probably due to the reduction of only one PME isoform. PME inhibition affected plant development as reflected by smaller stem elongation rates of selected transformants when compared with control plants, leading to a reduction in height throughout the entire course of development. Expansion rates of young developing leaves were measured simultaneously by two displacement transducers in the direction of the leaf tip (proximal-distal axis) and in the perpendicular direction (medial-lateral axis). Significant differences in leaf growth patterns were detected between wild-type and transgenic plants. We suggest that these visual phenotypes could be correlated with modifications of ion accumulation and partitioning within the transgenic plants. The ion-binding capacities of cell walls from PME-inhibited plants were specifically modified as they preferentially bound more sodium, but less potassium and calcium. X-ray microanalysis also indicated an increase in the concentration of several ions within the leaf apoplast of transgenic plants. Moreover, quantification of the total content of major cations revealed differences specific for a given element between the leaves of PME-inhibited and wild-type plants. Reduced growth rates might also be due to effects of PME inhibition on pectin metabolism, predominantly illustrated by an accumulation of galacturonic acid
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Polycomb Protein OsFIE2 Affects Plant Height and Grain Yield in Rice.
Directory of Open Access Journals (Sweden)
Xianbo Liu
Full Text Available Polycomb group (PcG proteins have been shown to affect growth and development in plants. To further elucidate their role in these processes in rice, we isolated and characterized a rice mutant which exhibits dwarfism, reduced seed setting rate, defective floral organ, and small grains. Map-based cloning revealed that abnormal phenotypes were attributed to a mutation of the Fertilization Independent Endosperm 2 (OsFIE2 protein, which belongs to the PcG protein family. So we named the mutant as osfie2-1. Histological analysis revealed that the number of longitudinal cells in the internodes decreased in osfie2-1, and that lateral cell layer of the internodes was markedly thinner than wild-type. In addition, compared to wild-type, the number of large and small vascular bundles decreased in osfie2-1, as well as cell number and cell size in spikelet hulls. OsFIE2 is expressed in most tissues and the coded protein localizes in both nucleus and cytoplasm. Yeast two-hybrid and bimolecular fluorescence complementation assays demonstrated that OsFIE2 interacts with OsiEZ1 which encodes an enhancer of zeste protein previously identified as a histone methylation enzyme. RNA sequencing-based transcriptome profiling and qRT-PCR analysis revealed that some homeotic genes and genes involved in endosperm starch synthesis, cell division/expansion and hormone synthesis and signaling are differentially expressed between osfie2-1 and wild-type. In addition, the contents of IAA, GA3, ABA, JA and SA in osfie2-1 are significantly different from those in wild-type. Taken together, these results indicate that OsFIE2 plays an important role in the regulation of plant height and grain yield in rice.
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Tamoi, Masahiro; Hiramatsu, Yoshie; Nedachi, Shigeki; Otori, Kumi; Tanabe, Noriaki; Maruta, Takanori; Shigeoka, Shigeru
2011-05-01
We generated transgenic tobacco plants with high levels of fructose-1,6-bisphosphatase expressing cyanobacterialfructose-1,6-/sedoheptulose-1,7-bisphosphatase in the cytosol. At ambient CO(2) levels (360 ppm), growth, photosynthetic activity, and fresh weight were unchanged but the sucrose/hexose/starch ratio was slightly altered in the transgenic plants compared with wild-type plants. At elevated CO(2) levels (1200 ppm), lateral shoot, leaf number, and fresh weight were significantly increased in the transgenic plants. Photosynthetic activity was also increased. Hexose accumulated in the upper leaves in the wild-type plants, while sucrose and starch accumulated in the lower leaves and lateral shoots in the transgenic plants. These findings suggest that cytosolic fructose-1,6-bisphosphatase contributes to the efficient conversion of hexose into sucrose, and that the change in carbon partitioning affects photosynthetic capacity and morphogenesis at elevated CO(2) levels.
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International Nuclear Information System (INIS)
Kanton, R.A.L.; Dennett, M.D.
2008-01-01
use efficiency in sole and intercrops are greatly affected by morphological characteristics of the component crops. In choosing cropping partners for intercropping special attention should be given to selecting cereal crops with erect leaves against those with droopy leaves. The under-storey legume crop should also have erect or semi erect leaves as to capture radiation filtering through the cereal canopy in order to maximize the capture and use of photosynthetically active radiation for increased and stable
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Directory of Open Access Journals (Sweden)
Anna Rudzińska-Langwald
2014-01-01
Full Text Available In Limonium sinuatum Mill, plants with severe symptoms of aster yellows infection phytoplasmas were present not only in the phloem but also in some cortex parenchymas cells. These parenchyma cells were situated at some distance from the conducting bundles. The phytoplasmas were observed directly in parenchyma cells cytoplasm. The number of phytoplasmas present in each selected cell varies. The cells with a small number of phytoplasmas show little pathological changes compared with the unaffected cells of the same zone of the stem as well with the cells of healthy plants. The cells filled with a number of phytoplasmas had their protoplast very much changed. The vacuole was reduced and in the cytoplasm a reduction of the number of ribosomes was noted and regions of homogenous structure appeared. Mitochondria were moved in the direction of the tonoplast and plasma membrane. Compared to the cells unaffected by phytoplasma, the mitochondria were smaller and had an enlarged cristae internal space. The chloroplasts from affected cells had a very significant reduction in size and the tylacoids system had disappeared. The role of these changes for creating phytoplasma friendly enviroment is discused.
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International Nuclear Information System (INIS)
Kurdali, F.; Al-Ain, F.; Razok, A.; Al-Shamma, M.
2008-01-01
A field experiment was conducted on a salt-affected soil to determine the effect of application of three types of Dhaincha (Sesbania aculeata pers.) residues (R, roots; L, shoots; L+R, shoots plus roots) of on the performance of sorghum (Sorghum bicolor L.) using the indirect 15 N isotopic dilution technique. Results indicated that Sesbania residues (L and L+R), used as green manures significantly increased grain yield, dry matter production, N uptake, and water use efficiency of sorghum. Percentages of N derived from residues (%Ndfr) in sorghum ranged from 6.4 to 28%. The N recoveries in sorghum were 52, 19. and 19.7% of the total amount contained in Sesbania roots, shoots and roots plus shoots, respectively. The beneficial effects of Sesbania residues are attributed not only to the additional N availability to the plants, but also to effects on the enhancement of soil N uptake, particularly in the L+R treatment. The findings suggest that the use of Sesbania aculeata residues, as a green manure, can provide a substantial portion of total N in sorghum. In addition, the use of Sesbania green manure in salt-affected soils, as a bio-reclaiming material, can be a promising approach for enhancing plant growth on a sustainable basis. (author)
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Agave salmiana Plant Communities in Central Mexico as Affected by Commercial Use
Martínez Salvador, Martin; Mata-González, Ricardo; Morales Nieto, Carlos; Valdez-Cepeda, Ricardo
2012-01-01
Agave salmiana is a native plant species harvested for the commercial production of mezcal ( Agave spirits) in the highlands of central Mexico. The objective of this study was to identify vegetation changes in natural communities where A. salmiana has been differentially harvested for commercial purposes. Three plant community categories were identified in the state of Zacatecas based on their history of A. salmiana utilization: short (less than 10 years of use), moderate (about 25 years), and long (60 or more years). Species cover, composition, and density were evaluated in field surveys by use category. A gradient of vegetation structure of the communities parallels the duration of A. salmiana use. A. salmiana density was greatest (3,125 plants ha-1) in the short-use areas and less (892 plants ha-1) in the moderate-use areas, associated with markedly greater density of shrubs (200%) and Opuntia spp. (50%) in moderate-use areas. The main shrubs were Larrea tridentata, Mimosa biuncifera, Jatropha dioica and Buddleia scordioides while the main Opuntia species were Opuntia leucotricha and Opuntia robusta. A. salmiana density was least (652 plants ha-1) in the long-use areas where shrubs were less abundant but Opuntia spp. density was 25% higher than in moderate-use areas. We suggest that shrubs may increase with moderate use creating an intermediate successional stage that facilitates the establishment of Opuntia spp. Long-term Agave use is generating new plant communities dominated by Opuntia spp. (nopaleras) as a replacement of the original communities dominated by A. salmiana (magueyeras).
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Energy Technology Data Exchange (ETDEWEB)
Yu, Zicheng; Apps, M.J.; Bhatti, J.S. [Canadan Forest Service, Edmonton (Canada). Northern Forestry Centre
2002-06-01
Species composition, detritus, and soil data from 97 boreal forest stands along a transect in central Canada were analysed using Correspondence Analysis to determine the dominant environmental/site variables that differentiate these forest stands. Picea mariana stands were densely clustered together on the understorey DCA plot, suggesting a consistent understorey species composition (feather mosses and Ericaceae), whereas Populus tremuloides stands had the most diverse understorey species composition (ca. 30 species, mostly shrubs and herbs). Pinus banksiana stands had several characteristic species of reindeer lichens (Cladina spp.), but saplings and Pinus seedlings were rare. Although climatic variables showed large variation along the transect, the CCA results indicated that site conditions are more important in determining species composition and differentiating the stand types. Forest floor characteristics (litter and humus layer, woody debris, and drainage) appear to be among the most important site variables. Stands of Picea had significantly higher average carbon (C) densities in the combined litter and humus layer (43,530 kg-C/ha) than either Populus (25,500 kg-C/ha) or Pinus (19,400 kg-C/ha). The thick surface organic layer in lowland Picea stands plays an important role in regulating soil temperature and moisture, and organic-matter decomposition, which in turn affect the ecosystem C-dynamics. During forest succession after a stand-replacing disturbance (e.g. fires), tree biomass and surface organic layer thickness increase in all stand types as forests recover; however, woody biomass detritus first decreases and then increases after ca. 80 yr. Soil C densities show slight decrease with ages in Populus stands, but increase in other stand types. These results indicate the complex C-transfer processes among different components (tree biomass, detritus, forest floor, and soil) of boreal ecosystems at various stages of succession.
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International Nuclear Information System (INIS)
Kumar, Manoj; Haldar, T.K.; Gupta, S.K.; Ramamurty, C.B.
1992-01-01
The heavy water plant being parasitic in nature, its design, operation and performance is affected to a great extent by the design, performance and operation of the ammonia plant. Some of the factors which affect the performance of heavy water plant such as on-stream hours and capacity utilisation of the ammonia plant, deuterium concentration (D/D+H) in feed synthesis gas, operating pressure of synthesis loop of ammonia plant, composition of feed synthesis gas, and level of oxygenated impurities in feed synthesis gas are described in this paper. (author). 3 tabs., 4 figs
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Chelsea M. Curtis; W. Michael Aust; John R. Seiler; Brian D. Strahm
2015-01-01
Forest mitigation sites may have poor survival and growth of planted trees due to poor drainage, compacted soils, and lack of microtopography. The effects of five replications of five forestry mechanical site preparation techniques (Flat, Rip, Bed, Pit, and Mound), four regeneration sources (Direct seed, Bare root, Tubelings, and Gallon), and three planting aids (None...
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Soil warming and CO2 enrichment induce biomass shifts in alpine tree line vegetation.
Dawes, Melissa A; Philipson, Christopher D; Fonti, Patrick; Bebi, Peter; Hättenschwiler, Stephan; Hagedorn, Frank; Rixen, Christian
2015-05-01
Responses of alpine tree line ecosystems to increasing atmospheric CO2 concentrations and global warming are poorly understood. We used an experiment at the Swiss tree line to investigate changes in vegetation biomass after 9 years of free air CO2 enrichment (+200 ppm; 2001-2009) and 6 years of soil warming (+4 °C; 2007-2012). The study contained two key tree line species, Larix decidua and Pinus uncinata, both approximately 40 years old, growing in heath vegetation dominated by dwarf shrubs. In 2012, we harvested and measured biomass of all trees (including root systems), above-ground understorey vegetation and fine roots. Overall, soil warming had clearer effects on plant biomass than CO2 enrichment, and there were no interactive effects between treatments. Total plant biomass increased in warmed plots containing Pinus but not in those with Larix. This response was driven by changes in tree mass (+50%), which contributed an average of 84% (5.7 kg m(-2) ) of total plant mass. Pinus coarse root mass was especially enhanced by warming (+100%), yielding an increased root mass fraction. Elevated CO2 led to an increased relative growth rate of Larix stem basal area but no change in the final biomass of either tree species. Total understorey above-ground mass was not altered by soil warming or elevated CO2 . However, Vaccinium myrtillus mass increased with both treatments, graminoid mass declined with warming, and forb and nonvascular plant (moss and lichen) mass decreased with both treatments. Fine roots showed a substantial reduction under soil warming (-40% for all roots soil depth) but no change with CO2 enrichment. Our findings suggest that enhanced overall productivity and shifts in biomass allocation will occur at the tree line, particularly with global warming. However, individual species and functional groups will respond differently to these environmental changes, with consequences for ecosystem structure and functioning. © 2014 John Wiley & Sons Ltd.
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Configuration management of plant modifications for nuclear power plants
International Nuclear Information System (INIS)
Ritsch, W.J.
1987-01-01
Due to the increasing complexity of nuclear power plant operation, regulatory pressure, and the large numbers of people required to operate and support the stations, the control of plant modifications at these plants needs to be expanded and improved. The aerospace and defense industries, as well as the owners or operators of large energy projects have established configuration management programs (CMPs) to control plant design changes. These programs are composed of well-defined functions for identifying, evaluating, recording, tracking, issuing, and documenting the established baseline conditions, as well as required changes to these baseline conditions. The purpose of this paper is to describe a recommended CMP for plant modifications consisting of a computerized data base installed on the utility's computer to provide a central storage of plant design and operations data necessary to control the following activities as they are affected by plant design changes: training; record management; operations; maintenance; health physics; planning/scheduling; procurement/inventory control; outage management (including modifications); and emergency response
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Martínez, Eliana; Rös, Matthias; Bonilla, María Argenis; Dirzo, Rodolfo
2015-01-01
The expansion of the agricultural frontier by the clearing of remnant forests has led to human-dominated landscape mosaics. Previous studies have evaluated the effect of these landscape mosaics on arthropod diversity at local spatial scales in temperate and tropical regions, but little is known about fragmentation effects in crop systems, such as the complex tropical traditional crop systems that maintain a high diversity of weeds and arthropods in low-Andean regions. To understand the factors that influence patterns of diversity in human-dominated landscapes, we investigate the effect of land use types on plant and arthropod diversity in traditionally managed cornfields, via surveys of plants and arthropods in twelve traditional cornfields in the Colombian Andes. We estimated alpha and beta diversity to analyze changes in diversity related to land uses within a radius of 100 m to 1 km around each cornfield. We observed that forests influenced alpha diversity of plants, but not of arthropods. Agricultural lands had a positive relationship with plants and herbivores, but a negative relationship with predators. Pastures positively influenced the diversity of plants and arthropods. In addition, forest cover seemed to influence changes in plant species composition and species turnover of herbivore communities among cornfields. The dominant plant species varied among fields, resulting in high differentiation of plant communities. Predator communities also exhibited high turnover among cornfields, but differences in composition arose mainly among rare species. The crop system evaluated in this study represents a widespread situation in the tropics, therefore, our results can be of broad significance. Our findings suggest that traditional agriculture may not homogenize biological communities, but instead could maintain the regional pool of species through high beta diversity.
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Jing, Jingying; Bezemer, T. Martijn; Van der Putten, Wim H.
2015-01-01
Plant–soil feedback can affect plants that belong to the same (intraspecific feedback) or different species (interspecific feedback). However, little is known about how intra- and interspecific plant–soil feedbacks influence interspecific plant competition. Here, we used plants and soil from
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Varga, Sandra
2015-03-01
• Arbuscular mycorrhizal fungi usually enhance overall plant performance, yet their effects on seed germination and early plant establishment, crucial steps in plant cycles, are generally overlooked. In gynodioecious species, sexual dimorphism in these traits has been reported, with females producing seeds that germinate at a faster rate than seeds from hermaphrodites.• Using the gynodioecious plant Geranium sylvaticum, I investigated in a greenhouse experiment whether the presence of arbuscular mycorrhizal spores affects seed germination and early plant establishment, examining at the same time whether the sex of the mother producing the seeds also influences these parameters and whether sex-specific interactions between these two factors exist.• The presence of arbuscular mycorrhizal spores in the soil decreased seed germination, did not affect plant survival, but did increase plant growth. Moreover, no significant differences in seed traits were detected between the sexes of the plants producing the seeds.• This study demonstrates that arbuscular mycorrhizal fungi may have contrasting effects for plants during early life stages and that mycorrhizal effects can take place even at the precolonization stage. © 2015 Botanical Society of America, Inc.
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International Nuclear Information System (INIS)
Kanton, R. A. L.; Dennett, M. D.
2008-01-01
and use efficiency in sole and intercrops are greatly affected by morphological characteristics of the component crops. In choosing cropping partners for intercropping special attention should be given to selecting cereal crops with erect leaves as against those with droopy leaves. The under-storey legume crop should also have erect or semi erect leaves so as to capture radiation filtering through the cereal canopy in order to maximize the capture and use of photosynthetically active radiation for increased and stable yields. (au)
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Directory of Open Access Journals (Sweden)
Eliana Martínez
Full Text Available The expansion of the agricultural frontier by the clearing of remnant forests has led to human-dominated landscape mosaics. Previous studies have evaluated the effect of these landscape mosaics on arthropod diversity at local spatial scales in temperate and tropical regions, but little is known about fragmentation effects in crop systems, such as the complex tropical traditional crop systems that maintain a high diversity of weeds and arthropods in low-Andean regions. To understand the factors that influence patterns of diversity in human-dominated landscapes, we investigate the effect of land use types on plant and arthropod diversity in traditionally managed cornfields, via surveys of plants and arthropods in twelve traditional cornfields in the Colombian Andes. We estimated alpha and beta diversity to analyze changes in diversity related to land uses within a radius of 100 m to 1 km around each cornfield. We observed that forests influenced alpha diversity of plants, but not of arthropods. Agricultural lands had a positive relationship with plants and herbivores, but a negative relationship with predators. Pastures positively influenced the diversity of plants and arthropods. In addition, forest cover seemed to influence changes in plant species composition and species turnover of herbivore communities among cornfields. The dominant plant species varied among fields, resulting in high differentiation of plant communities. Predator communities also exhibited high turnover among cornfields, but differences in composition arose mainly among rare species. The crop system evaluated in this study represents a widespread situation in the tropics, therefore, our results can be of broad significance. Our findings suggest that traditional agriculture may not homogenize biological communities, but instead could maintain the regional pool of species through high beta diversity.
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Soliveres, Santiago; Torices, Rubén; Maestre, Fernando T.
2015-01-01
Positive and negative plant-plant interactions are major processes shaping plant communities. They are affected by environmental conditions and evolutionary relationships among the interacting plants. However, the generality of these factors as drivers of pairwise plant interactions and their combined effects remain virtually unknown. We conducted an observational study to assess how environmental conditions (altitude, temperature, irradiance and rainfall), the dispersal mechanism of beneficiary species and evolutionary relationships affected the co-occurrence of pairwise interactions in 11 Stipa tenacissima steppes located along an environmental gradient in Spain. We studied 197 pairwise plant-plant interactions involving the two major nurse plants (the resprouting shrub Quercus coccifera and the tussock grass S. tenacissima) found in these communities. The relative importance of the studied factors varied with the nurse species considered. None of the factors studied were good predictors of the co-ocurrence between S. tenacissima and its neighbours. However, both the dispersal mechanism of the beneficiary species and the phylogenetic distance between interacting species were crucial factors affecting the co-occurrence between Q. coccifera and its neighbours, while climatic conditions (irradiance) played a secondary role. Values of phylogenetic distance between 207-272.8 Myr led to competition, while values outside this range or fleshy-fruitness in the beneficiary species led to positive interactions. The low importance of environmental conditions as a general driver of pairwise interactions was caused by the species-specific response to changes in either rainfall or radiation. This result suggests that factors other than climatic conditions must be included in theoretical models aimed to generally predict the outcome of plant-plant interactions. Our study helps to improve current theory on plant-plant interactions and to understand how these interactions can
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Relative floral density of an invasive plant affects pollinator foraging behaviour on a native plant
Directory of Open Access Journals (Sweden)
Amy Marie Iler
2014-08-01
Full Text Available Interactions between invasive and native plants for pollinators vary from competition to facilitation of pollination of native plants. Theory predicts that relative floral densities should account for some of this variation in outcomes, with facilitation at low floral densities and competition at high floral densities of the invader. We tested this prediction by quantifying pollination and female reproductive success of a native herb, Geranium maculatum, in three experimental arrays that varied in floral density of the invasive shrub Lonicera maackii: control (no L. maackii, low floral density of L. maackii, and high floral density of L. maackii. A low density of L. maackii flowers was associated with an increase in pollinator visitation rate to G. maculatum flowers and an increase in conspecific pollen deposition compared to controls and high density arrays. Increased visitation rates were not associated with an increase in the number of visitors to low density arrays, suggesting instead that a behavioural switch in visitation within the array accounted for increased pollen deposition. In contrast, the only evidence of competition in high density arrays was a shorter duration of visits to G. maculatum flowers relative to the other treatments. The number of seeds per flower did not vary among treatments, although trends in seeds per flower were consistent with patterns of pollinator foraging behaviour. Given increased pollinator visits and pollen deposition at a low density of the invader, our study indicates that complete eradication of invasives as a management or restoration technique may have unintended negative consequences for pollination of native plants.
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Kurm, Viola; Putten, Van Der Wim H.; Pineda, Ana; Hol, G.W.H.
2018-01-01
• Background and Aims: Plant growth-promoting rhizobacteria (PGPR) strains can influence plant-insect interactions. However, little is known about the effect of changes in the soil bacterial community in general and especially the loss of rare soil microbes on these interactions. Here, the influence
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Energy Technology Data Exchange (ETDEWEB)
Ahonen-Jonnarth, U.
1996-04-01
In this work, nickel and copper exposure on Scots pine (Pinus sylvestris L.) was studied experimentally under field conditions. The significance of some biotic factors was also studied. We wanted to test whether the understorey lichen layer has a protective role against nickel exposure, and whether it has any effects on pine seedlings. Effects of defoliation, simulating sawfly grazing, were also examined, since the reduced photosynthesis can be assumed to affect root growth and ectomycorrhiza negatively. Ectomycorrhizal colonization has been found to decrease in pinyon pine due to defoliation. 19 refs
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A Review of Plant Growth Substances
Directory of Open Access Journals (Sweden)
D.A. Agboola
2014-10-01
Full Text Available Plant growth substances are compounds, either natural or synthetic that modifies or controls through physiological action, the growth and maturation of plants. If the compound is produced within the plant, it is called a plant hormone or phytohormone. In general, it is accepted that there are five major classes of plant hormones. They are Auxins (IAA, Cytokinins, Gibberellins, Ethylene and Abscisic Acid. However, there are still many plant growth substances that cannot be grouped under these classes, though they also perform similar functions, inhibiting or promoting plant growth. These substances include Brassinosteroids (Brassins, Salicylic Acid, Jasmonic Acid, Fusicoccin, Batasins, Strigolactones, Growth stimulants (e.g. Hymexazol and Pyripropanol, Defoliants (e.g. Calcium Cyanamide, Dimethipin. Researchers are still working on the biosynthetic pathways of some of these substances. Plant growth substances are very useful in agriculture in both low and high concentrations. They affect seed growth, time of flowering, the sex of flowers, senescence of leaves and fruits, leaf formation, stem growth, fruit development and ripening, plant longevity, and even plant death. Some synthetic regulators are also used as herbicides and pesticides. Therefore, attention should be paid to the production and synthesis of these substances so that they affect plants in a way that would favour yield.
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Czech Academy of Sciences Publication Activity Database
Verheyen, E.; Baeten, L.; De Frenne, P.; Brnhardt-Römermann, M.; Brunet, J.; Cornelis, J.; Decocq, G.; Dierschke, H.; Eriksson, O.; Hédl, Radim; Heinken, T.; Hermy, M.; Hommel, P.; Kirby, K.; Naaf, T.; Peterken, G.; Petřík, Petr; Pfadenhauer, J.; Van Calster, H.; Walther, G.-R.; Wulf, M.; Verstraeten, G.
2012-01-01
Roč. 100, č. 2 (2012), s. 352-365 ISSN 0022-0477 R&D Projects: GA AV ČR IAA600050812 Institutional research plan: CEZ:AV0Z60050516 Keywords : Ellenberg indicator values * forest management * large herbivores Subject RIV: EF - Botanics Impact factor: 5.431, year: 2012
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International Nuclear Information System (INIS)
Galean, L.; Gamarra, R.; Sainz, H.; Millan, R.
2010-01-01
It is difficult for sites affected by mining to be colonized by vegetation and thus they suffer a slow recovery to a healthy ecosystem and, as a result, restoration work is necessary. The aim of this report is to propose a set of native species which are conducive to establishing a stable and self-sufficient plant community that will protect the soil and contribute to the rapid integration into the landscape of the areas affected by mining in the upper basin of the river Rodrigatos in the region of El Bierzo (Leon) An analysis of plant communities was undertaken using the phyto sociological method of Braun-Blanquet in order to subsequently select, using ecological criteria, the most suitable species for revegetation. Plant mapping using ortho photos was also developed in order to identify and delineate the location of the different landscape units. Among candidate species, in the first revegetation phase, we suggest a variety of herbs that are able to fix soils and protect them from erosion; species of the genus Cytisus and Genista in areas of moderate slope and species such as Rumex induratus Boiss and Reuter, Erysimum linifolium (Pourr. Ex Pers .) Jay in steeper areas because of their rooting ability. In later stages, the introduction of tree species characteristic for each formation is recommended. Furthermore, in the riverside areas species such as Carex elata subsp.reuteriana (Boiss.) Lucen and Aedo, Alnus glutinosa (L.) and Salix atrocinerea Brot. are proposed for introduction from the fi rst stage onwards. The species proposed in this study include some not commonly used in restoration, so a subsequent more detailed study would be required in order to assess their degree of suitability for this use. (Author) 65 refs.
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Forrest, Kerrie L; Bhave, Mrinal
2007-10-01
The ubiquitous cell membrane proteins called aquaporins are now firmly established as channel proteins that control the specific transport of water molecules across cell membranes in all living organisms. The aquaporins are thus likely to be of fundamental significance to all facets of plant growth and development affected by plant-water relations. A majority of plant aquaporins have been found to share essential structural features with the human aquaporin and exhibit water-transporting ability in various functional assays, and some have been shown experimentally to be of critical importance to plant survival. Furthermore, substantial evidence is now available from a number of plant species that shows differential gene expression of aquaporins in response to abiotic stresses such as salinity, drought, or cold and clearly establishes the aquaporins as major players in the response of plants to conditions that affect water availability. This review summarizes the function and regulation of these genes to develop a greater understanding of the response of plants to water insufficiency, and particularly, to identify tolerant genotypes of major crop species including wheat and rice and plants that are important in agroforestry.
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Zoospore exudates from Phytophthora nicotianae affect immune responses in Arabidopsis.
Kong, Ping; McDowell, John M; Hong, Chuanxue
2017-01-01
Zoospore exudates play important roles in promoting zoospore communication, homing and germination during plant infection by Phytophthora. However, it is not clear whether exudates affect plant immunity. Zoospore-free fluid (ZFF) and zoospores of P. nicotianae were investigated comparatively for effects on resistance of Arabidopsis thaliana Col-0 and mutants that affect signaling mediated by salicylic acid (SA) and jasmonic acid (JA): eds16 (enhanced disease susceptibility16), pad4 (phytoalexin deficient4), and npr1 (nonexpressor of pathogenesis-related genes1). Col-0 attracted more zoospores and had severe tissue damage when flooded with a zoospore suspension in ZFF. Mutants treated with ZFF alone developed disease symptoms similar to those inoculated with zoospores and requirements of EDS16 and PAD4 for plant responses to zoospores and the exudates was apparent. Zoospore and ZFFs also induced expression of the PR1 and PDF1.2 marker genes for defense regulated by SA and JA, respectively. However, ZFF affected more JA defense signaling, down regulating PR1 when SA signaling or synthesis is deficient, which may be responsible for Arabidopsis mutant plants more susceptible to infection by high concentration of P. nicotianae zoospores. These results suggest that zoospore exudates can function as virulence factors and inducers of plant immune responses during plant infection by Phytophthora.
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Plant growth promoting bacteria as an alternative strategy for salt tolerance in plants: A review.
Numan, Muhammad; Bashir, Samina; Khan, Yasmin; Mumtaz, Roqayya; Shinwari, Zabta Khan; Khan, Abdul Latif; Khan, Ajmal; Al-Harrasi, Ahmed
2018-04-01
Approximately 5.2 billion hectare agriculture land are affected by erosion, salinity and soil degradation. Salinity stress has significantly affecting the fertile lands, and therefore possesses a huge impact on the agriculture and economy of a country. Salt stress has severe effects on the growth and development of plants as well as reducing its yield. Plants are inherently equipped with stress tolerance ability to responds the specific type of stress. Plants retained specific mechanisms for salt stress mitigation, such as hormonal stimulation, ion exchange, antioxidant enzymes and activation of signaling cascades on their metabolic and genetic frontiers that sooth the stressed condition. Additional to the plant inherent mechanisms, certain plant growth promoting bacteria (PGPB) also have specialized mechanism that play key role for salt stress tolerance and plant growth promotion. These bacteria triggers plants to produce different plant growth hormones like auxin, cytokinine and gibberellin as well as volatile organic compounds. These bacteria also produces growth regulators like siderophore, which fix nitrogen, solubilize organic and inorganic phosphate. Considering the importance of PGPB in compensation of salt tolerance in plants, the present study has reviewed the different aspect and mechanism of bacteria that play key role in promoting plants growth and yield. It can be concluded that PGPB can be used as a cost effective and economical tool for salinity tolerance and growth promotion in plants. Copyright © 2018 Elsevier GmbH. All rights reserved.
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Plant hormones as signals in arbuscular mycorrhizal symbiosis.
Miransari, Mohammad; Abrishamchi, A; Khoshbakht, K; Niknam, V
2014-06-01
Arbuscular mycorrhizal (AM) fungi are non-specific symbionts developing mutual and beneficial symbiosis with most terrestrial plants. Because of the obligatory nature of the symbiosis, the presence of the host plant during the onset and proceeding of symbiosis is necessary. However, AM fungal spores are able to germinate in the absence of the host plant. The fungi detect the presence of the host plant through some signal communications. Among the signal molecules, which can affect mycorrhizal symbiosis are plant hormones, which may positively or adversely affect the symbiosis. In this review article, some of the most recent findings regarding the signaling effects of plant hormones, on mycorrhizal fungal symbiosis are reviewed. This may be useful for the production of plants, which are more responsive to mycorrhizal symbiosis under stress.
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Martínez-Medina, Ainhoa; Del Mar Alguacil, Maria; Pascual, Jose A.; van Wees, Saskia C M|info:eu-repo/dai/nl/185445373
2014-01-01
The application of Trichoderma strains with biocontrol and plant growth-promoting capacities to plant substrates can help reduce the input of chemical pesticides and fertilizers in agriculture. Some Trichoderma isolates can directly affect plant pathogens, but they also are known to influence the
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Regulating nutrient allocation in plants
Udvardi, Michael; Yang, Jiading; Worley, Eric
2014-12-09
The invention provides coding and promoter sequences for a VS-1 and AP-2 gene, which affects the developmental process of senescence in plants. Vectors, transgenic plants, seeds, and host cells comprising heterologous VS-1 and AP-2 genes are also provided. Additionally provided are methods of altering nutrient allocation and composition in a plant using the VS-1 and AP-2 genes.
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Directory of Open Access Journals (Sweden)
J. A. Hudson
1997-01-01
Full Text Available Annual water balances (1983-1995 for the Cwm and Delyn catchments at Llanbrynmair Moor in mid-Wales have been used to quantify the hydrological effects of the land use change in the Cwm from moorland to forestry. Initially, the actual evaporation (precipitation minus streamflow of the Cwm catchment declined rapidly relative to the Delyn, due to the disruption of the vegetation by ploughing the ground in preparation for planting the trees. It then increased, more quickly than expected, to greater levels than for the original moorland since in the early stages of forest growth a dense understorey of dwarf shrubs contributed to both interception and transpiration.
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Volatile chemical interaction between undamaged plants
Glinwood, Robert
2010-01-01
This chapter discusses whether plant chemical communication is a mechanism by which plant genetic diversity can affect the natural enemies of herbivores. Plant genetic diversity influences natural enemies, and these insects use volatile chemical cues to locate suitable habitats. However, the importance of chemical communication for these interactions has not been considered. In this chapter, the latest research on chemical communication between undamaged plants is reviewed. ...
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Phosphate stresses affect ionome and metabolome in tea plants.
Ding, Zhaotang; Jia, Sisi; Wang, Yu; Xiao, Jun; Zhang, Yinfei
2017-11-01
In order to study the response of tea plants to P stress, we conducted the ionomic and metabolomic analysis by ICP-OES, GC-MS and LC-MS. The results demonstrated that P was antagonistic with S, and was cooperative with Cu, Zn, Mn and Fe under P-deficiency. However, P was antagonistic with Mn, Fe and S, and was cooperative with Cu and Zn under P-excess. Moreover, P-deficiency or excess reduced the syntheses of flavonoids and phosphorylated metabolites. P-deficiency decreased the amount of glutamate and increased the content of glutamine, while P-excess decreased the content of glutamine. Besides, P-deficiency increased three organic acids and decreased three organic acids. P-excess increased the contents of malic acid, oxalic acid, ribonic acid and etc. involved in primary metabolism, but decreased the contents of p-coumaric acid, indoleacrylic acid, related to secondary metabolism. Furthermore, the contents of Mn and Zn were found to be positively related to the amounts of myricetin and quercetin, and the content of Mn to be positively related to the amount of arabinose. The results implied that the P stresses severely disturbed the metabolism of minerals and metabolites in tea plants, which influenced the yield and quality of tea. Copyright © 2017. Published by Elsevier Masson SAS.
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Plant community development is affected by nutrients and soil biota
De Deyn, G.B.; Raaijmakers, C.E.; Van der Putten, W.H.
2004-01-01
1 Plant community development depends to a great extent on the availability of soil nutrients, but recent studies underline the role of symbiotic, herbivorous and pathogenic soil biota. We tested for interactions between these biotic and abiotic factors by studying the effects of additional
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Zoospore exudates from Phytophthora nicotianae affect immune responses in Arabidopsis.
Directory of Open Access Journals (Sweden)
Ping Kong
Full Text Available Zoospore exudates play important roles in promoting zoospore communication, homing and germination during plant infection by Phytophthora. However, it is not clear whether exudates affect plant immunity. Zoospore-free fluid (ZFF and zoospores of P. nicotianae were investigated comparatively for effects on resistance of Arabidopsis thaliana Col-0 and mutants that affect signaling mediated by salicylic acid (SA and jasmonic acid (JA: eds16 (enhanced disease susceptibility16, pad4 (phytoalexin deficient4, and npr1 (nonexpressor of pathogenesis-related genes1. Col-0 attracted more zoospores and had severe tissue damage when flooded with a zoospore suspension in ZFF. Mutants treated with ZFF alone developed disease symptoms similar to those inoculated with zoospores and requirements of EDS16 and PAD4 for plant responses to zoospores and the exudates was apparent. Zoospore and ZFFs also induced expression of the PR1 and PDF1.2 marker genes for defense regulated by SA and JA, respectively. However, ZFF affected more JA defense signaling, down regulating PR1 when SA signaling or synthesis is deficient, which may be responsible for Arabidopsis mutant plants more susceptible to infection by high concentration of P. nicotianae zoospores. These results suggest that zoospore exudates can function as virulence factors and inducers of plant immune responses during plant infection by Phytophthora.
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Genes of the most conserved WOX clade in plants affect root and flower development in Arabidopsis
Directory of Open Access Journals (Sweden)
Moreau Hervé
2008-10-01
Full Text Available Abstract Background The Wuschel related homeobox (WOX family proteins are key regulators implicated in the determination of cell fate in plants by preventing cell differentiation. A recent WOX phylogeny, based on WOX homeodomains, showed that all of the Physcomitrella patens and Selaginella moellendorffii WOX proteins clustered into a single orthologous group. We hypothesized that members of this group might preferentially share a significant part of their function in phylogenetically distant organisms. Hence, we first validated the limits of the WOX13 orthologous group (WOX13 OG using the occurrence of other clade specific signatures and conserved intron insertion sites. Secondly, a functional analysis using expression data and mutants was undertaken. Results The WOX13 OG contained the most conserved plant WOX proteins including the only WOX detected in the highly proliferating basal unicellular and photosynthetic organism Ostreococcus tauri. A large expansion of the WOX family was observed after the separation of mosses from other land plants and before monocots and dicots have arisen. In Arabidopsis thaliana, AtWOX13 was dynamically expressed during primary and lateral root initiation and development, in gynoecium and during embryo development. AtWOX13 appeared to affect the floral transition. An intriguing clade, represented by the functional AtWOX14 gene inside the WOX13 OG, was only found in the Brassicaceae. Compared to AtWOX13, the gene expression profile of AtWOX14 was restricted to the early stages of lateral root formation and specific to developing anthers. A mutational insertion upstream of the AtWOX14 homeodomain sequence led to abnormal root development, a delay in the floral transition and premature anther differentiation. Conclusion Our data provide evidence in favor of the WOX13 OG as the clade containing the most conserved WOX genes and established a functional link to organ initiation and development in Arabidopsis, most
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Nolan, R. H.; Lane, P. N.; Mitchell, P. J.; Bradstock, R. A.
2011-12-01
Fire induced changes to the vegetation dynamics in temperate forests have been demonstrated to affect evapotranspiration (Et) rates through increases in plant size and density and stand-level transpiration and interception. In many cases these transient changes in forest structure result in substantial declines in stream flow for protracted periods after the disturbance. However to date research has focused on the wetter 'ash' forests of south-eastern Australia which solely regenerate via seedlings, it is unknown what changes in Et may occur in those forests which re-sprout post-fire. We hypothesize that Et fluxes track post-fire changes in sapwood area and leaf area index (L) in re-sprouting temperate forests, increasing as the forest regenerates. Following the 2009 Black Saturday wildfires in Victoria, we monitored Et rates for over a year in both damp and dry re-sprouting forest, incorporating a range of fire severity classes. Components of Et including overstorey transpiration, rainfall interception loss and forest floor Et were measured in conjunction with changes in L, sapwood area and leaf physiology. The monitoring period began one year post-fire with a typical hot, dry summer, at which stage Et rates in burnt forest were similar or less than those in unburnt forest. During the following summer, which was one of the wettest on record, Et increased across all monitoring plots but particularly so in the burnt forest where seedling regeneration resulted in an understorey L nearly twice that of unburnt forest. Forest floor Et was up to 46% higher in burnt forest, and rainfall interception values accounted for approximately 25% of rainfall compared to 15% in unburnt forest. The greatest increase in canopy transpiration rates over this period occurred in those trees subject to a low intensity fire where most of the canopy remained intact but there was also fire-triggered sprouting of new leaves along the trunk and main branches. In these trees rates of sapflow
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A fungal root symbiont modifies plant resistance to an insect herbivore.
Borowicz, Victoria A
1997-11-01
Vesicular-arbuscular mycorrhizal (VAM) fungi are common root-colonizing symbionts that affect nutrient uptake by plants and can alter plant susceptibility to herbivores. I conducted a factorial experiment to test the hypotheses that colonization by VAM fungi (1) improves soybean (Glycine max) tolerance to grazing by folivorous Mexican bean beetle (Epilachna varivestis), and (2) indirectly affects herbivores by increasing host resistance. Soybean seedlings were inoculated with the VAM fungus Glomus etunicatum or VAM-free filtrate and fertilized with high-[P] or low-[P] fertilizer. After plants had grown for 7 weeks first-instar beetle larvae were placed on bagged leaves. Growth of soybean was little affected by grazing larvae, and no effects of treatments on tolerance of soybeans to herbivores were evident. Colonization by VAM fungus doubled the size of phosphorus-stressed plants but these plants were still half the size of plants given adequate phosphorus. High-[P] fertilizer increased levels of phosphorus and soluble carbohydrates, and decreased levels of soluble proteins in leaves of grazed plants. Colonization of grazed plants by VAM fungus had no significant effect on plant soluble carbohydrates, but increased concentration of phosphorus and decreased levels of proteins in phosphorus-stressed plants to concentrations similar to those of plants given adequate phosphorus. Mexican bean beetle mass at pupation, pupation rate, and survival to eclosion were greatest for beetles reared on phosphorus-stressed, VAM-colonized plants, refuting the hypothesis that VAM colonization improves host plant resistance. VAM colonization indirectly affected performance of Mexician bean beetle larvae by improving growth and nutrition of the host plant.
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Liu, Xiaojie; Vrieling, Klaas; Klinkhamer, Peter G.L.
2017-01-01
The high structural diversity of plant metabolites suggests that interactions among them should be common. We investigated the effects of single metabolites and combinations of plant metabolites on insect herbivores. In particular we studied the interacting effects of pyrrolizidine alkaloid (PAs), and chlorogenic acid (CGA), on a generalist herbivore, Frankliniella occidentalis. We studied both the predominantly occurring PA N-oxides and the less frequent PA free bases. We found antagonistic effects between CGA and PA free bases on thrips mortality. In contrast PA N-oxides showed synergistic interactions with CGA. PA free bases caused a higher thrips mortality than PA N-oxides while the reverse was through for PAs in combination with CGA. Our results provide an explanation for the predominate storage of PA N-oxides in plants. We propose that antagonistic interactions represent a constraint on the accumulation of plant metabolites, as we found here for Jacobaea vulgaris. The results show that the bioactivity of a given metabolite is not merely dependent upon the amount and chemical structure of that metabolite, but also on the co-occurrence metabolites in, e.g., plant cells, tissues and organs. The significance of this study is beyond the concerns of the two specific groups tested here. The current study is one of the few studies so far that experimentally support the general conception that the interactions among plant metabolites are of great importance to plant-environment interactions. PMID:28611815
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Directory of Open Access Journals (Sweden)
Xiaojie Liu
2017-05-01
Full Text Available The high structural diversity of plant metabolites suggests that interactions among them should be common. We investigated the effects of single metabolites and combinations of plant metabolites on insect herbivores. In particular we studied the interacting effects of pyrrolizidine alkaloid (PAs, and chlorogenic acid (CGA, on a generalist herbivore, Frankliniella occidentalis. We studied both the predominantly occurring PA N-oxides and the less frequent PA free bases. We found antagonistic effects between CGA and PA free bases on thrips mortality. In contrast PA N-oxides showed synergistic interactions with CGA. PA free bases caused a higher thrips mortality than PA N-oxides while the reverse was through for PAs in combination with CGA. Our results provide an explanation for the predominate storage of PA N-oxides in plants. We propose that antagonistic interactions represent a constraint on the accumulation of plant metabolites, as we found here for Jacobaea vulgaris. The results show that the bioactivity of a given metabolite is not merely dependent upon the amount and chemical structure of that metabolite, but also on the co-occurrence metabolites in, e.g., plant cells, tissues and organs. The significance of this study is beyond the concerns of the two specific groups tested here. The current study is one of the few studies so far that experimentally support the general conception that the interactions among plant metabolites are of great importance to plant-environment interactions.
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International Nuclear Information System (INIS)
O'Brien, J.N.; Fainberg, A.
1984-04-01
This report presents a long-term research plan for addressing human factors which can adversely affect safeguards at nuclear power plants. It was developed in order to prioritize and propose research for NRC in regulating power plant safeguards. Research efforts addressing human factors in safeguards were developed and prioritized according to the importance of human factors areas. Research was also grouped to take advantage of common research approaches and data sources where appropriate. Four main program elements emerged from the analysis, namely (1) Training and Performance Evaluation, (2) Organizational Factors, (3) Man-Machine Interface, and (4) Trustworthiness and Reliability. Within each program element, projects are proposed with results and information flowing between program elements where useful. An overall research plan was developed for a 4-year period and it would lead ultimately to regulatory activities including rulemaking, regulatory guides, and technical bases for regulatory action. The entire plan is summarized in Volume 1 of this report
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Are native songbird populations affected by non-native plant invasion?
Amanda M. Conover; Christopher K. Williams; Vincent. D' Amico
2011-01-01
Development into forested areas is occurring rapidly across the United States, and many of the remnant forests within suburban landscapes are being fragmented into smaller patches, impacting the quality of this habitat for avian species. An ecological effect linked to forest fragmentation is the invasion of non-native plants into the ecosystem.
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Using a plant health system framework to assess plant clinic performance in Uganda
DEFF Research Database (Denmark)
Danielsen, Solveig; Matsiko, Frank B.
2016-01-01
and expand, new analytical frameworks and tools are needed to identify factors influencing performance of services and systems in specific contexts, and to guide interventions. In this paper we apply a plant health system framework to assess plant clinic performance, using Uganda as a case study...... factors, influenced by basic operational and financial concerns, inter-institutional relations and public sector policies. Overall, there was a fairly close match between the plant health system attributes and plant clinic performance, suggesting that the framework can help explain system functioning....... A comparative study of plant clinics was carried out between July 2010 and September 2011 in the 12 districts where plant clinics were operating at that time. The framework enabled us to organise multiple issues and identify key features that affected the plant clinics. Clinic performance was, among other...
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Natal Host Plants Can Alter Herbivore Competition.
Pan, Huipeng; Preisser, Evan L; Su, Qi; Jiao, Xiaoguo; Xie, Wen; Wang, Shaoli; Wu, Qingjun; Zhang, Youjun
2016-01-01
Interspecific competition between herbivores is widely recognized as an important determinant of community structure. Although researchers have identified a number of factors capable of altering competitive interactions, few studies have addressed the influence of neighboring plant species. If adaptation to/ epigenetic effects of an herbivore's natal host plant alter its performance on other host plants, then interspecific herbivore interactions may play out differently in heterogeneous and homogenous plant communities. We tested wether the natal host plant of a whitefly population affected interactions between the Middle-east Asia Minor 1 (MEAM1) and Mediterranean (MED) cryptic species of the whitefly Bemisia tabaci by rearing the offspring of a cabbage-derived MEAM1 population and a poinsettia-derived MED population together on three different host plants: cotton, poinsettia, and cabbage. We found that MED dominated on poinsettia and that MEAM1 dominated on cabbage, results consistent with previous research. MED also dominated when reared with MEAM1 on cotton, however, a result at odds with multiple otherwise-similar studies that reared both species on the same natal plant. Our work provides evidence that natal plants affect competitive interactions on another plant species, and highlights the potential importance of neighboring plant species on herbivore community composition in agricultral systems.
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Charbonnier, Yohan M; Barbaro, Luc; Barnagaud, Jean-Yves; Ampoorter, Evy; Nezan, Julien; Verheyen, Kris; Jactel, Hervé
2016-10-01
Species assemblages are shaped by local and continental-scale processes that are seldom investigated together, due to the lack of surveys along independent gradients of latitude and habitat types. Our study investigated changes in the effects of forest composition and structure on bat and bird diversity across Europe. We compared the taxonomic and functional diversity of bat and bird assemblages in 209 mature forest plots spread along gradients of forest composition and vertical structure, replicated in 6 regions spanning from the Mediterranean to the boreal biomes. Species richness and functional evenness of both bat and bird communities were affected by the interactions between latitude and forest composition and structure. Bat and bird species richness increased with broadleaved tree cover in temperate and especially in boreal regions but not in the Mediterranean where they increased with conifer abundance. Bat species richness was lower in forests with smaller trees and denser understorey only in northern regions. Bird species richness was not affected by forest structure. Bird functional evenness increased in younger and denser forests. Bat functional evenness was also influenced by interactions between latitude and understorey structure, increasing in temperate forests but decreasing in the Mediterranean. Covariation between bat and bird abundances also shifted across Europe, from negative in southern forests to positive in northern forests. Our results suggest that community assembly processes in bats and birds of European forests are predominantly driven by abundance and accessibility of feeding resources, i.e., insect prey, and their changes across both forest types and latitudes.
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Positions of human dwellings affect few tropical diseases near ...
African Journals Online (AJOL)
user
Some factors that possibly affect tropical disease distribution was investigated in about 500 randomize human dwellings. The studied factors include wild animals, domestic animals, wild plants, cultivated plants, nature of soil, nature of water, positions of human dwellings, nature of building material and position of animal ...
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Plant Defense Inhibitors Affect the Structures of Midgut Cells in and
Directory of Open Access Journals (Sweden)
Hongmei Li-Byarlay
2016-01-01
Full Text Available Plants produce proteins such as protease inhibitors and lectins as defenses against herbivorous insects and pathogens. However, no systematic studies have explored the structural responses in the midguts of insects when challenged with plant defensive proteins and lectins across different species. In this study, we fed two kinds of protease inhibitors and lectins to the fruit fly Drosophila melanogaster and alpha-amylase inhibitors and lectins to the cowpea bruchid Callosobruchus maculatus . We assessed the changes in midgut cell structures by comparing them with such structures in insects receiving normal diets or subjected to food deprivation. Using light and transmission electron microscopy in both species, we observed structural changes in the midgut peritrophic matrix as well as shortened microvilli on the surfaces of midgut epithelial cells in D. melanogaster . Dietary inhibitors and lectins caused similar lesions in the epithelial cells but not much change in the peritrophic matrix in both species. We also noted structural damages in the Drosophila midgut after six hours of starvation and changes were still present after 12 hours. Our study provided the first evidence of key structural changes of midguts using a comparative approach between a dipteran and a coleopteran. Our particular observation and discussion on plant–insect interaction and dietary stress are relevant for future mode of action studies of plant defensive protein in insect physiology.
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Directory of Open Access Journals (Sweden)
Roberto Pasetto
2013-03-01
Full Text Available INTRODUCTION. A method to select populations living in areas affected by diffuse environmental contamination is presented, with particular regard to oil refineries, in the Italian context. The reasons to use municipality instead of census tract populations for environment and health small-area studies of contaminated sites are discussed. METHODS. Populations most affected by diffuse environmental contamination are identified through a geoprocessing model. Data from the national census 2001 were used to estimate census tract level populations. A geodatabase was developed using the municipality and census tract layers provided by the Italian National Bureau of Statistics (ISTAT. The orthophotos of the Italian territory - year 2006 - available on the geographic information systems (GIS of the National Cartographic Portal, were considered. The area within 2 km from the plant border was used as an operational definition to identify the area at major contamination. RESULTS. The geoprocessing model architecture is presented. The results of its application to the selection of municipality populations in a case study are shown. CONCLUSIONS. The application of the proposed geoprocessing model, the availability of long time series of mortality and morbidity data, and a quali-quantitative estimate of contamination over time, could allow an appraisal of the health status of populations affected by oil refinery emissions.
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Snoeren, Tjeerd A L; Mumm, Roland; Poelman, Erik H; Yang, Yue; Pichersky, Eran; Dicke, Marcel
2010-05-01
The indirect defense mechanisms of plants comprise the production of herbivore-induced plant volatiles that can attract natural enemies of plant attackers. One of the often emitted compounds after herbivory is methyl salicylate (MeSA). Here, we studied the importance of this caterpillar-induced compound in the attraction of the parasitoid wasp Diadegma semiclausum by using a mutant Arabidopsis line. Pieris rapae infested AtBSMT1-KO mutant Arabidopsis plants, compromised in the biosynthesis of MeSA, were more attractive to parasitoids than infested wild-type plants. This suggests that the presence of MeSA has negative effects on parasitoid host-finding behavior when exposed to wild-type production of herbivore-induced Arabidopsis volatiles. Furthermore, in line with this, we recorded a positive correlation between MeSA dose and repellence of D. semiclausum when supplementing the headspace of caterpillar-infested AtBSMT1-KO plants with synthetic MeSA.
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PHYSIOLOGICAL RESPONSES OF DWARF COCONUT PLANTS UNDER WATER DEFICIT IN SALT - AFFECTED SOILS
Directory of Open Access Journals (Sweden)
ALEXANDRE REUBER ALMEIDA DA SILVA
2017-01-01
Full Text Available The objective of this study was to characterize the physiological acclimation responses of young plants of the dwarf coconut cultivar ̳Jiqui Green‘ associated with tolerance to conditions of multiple abiotic stresses (drought and soil salinity, acting either independently or in combination. The study was conducted under controlled conditions and evaluated the following parameters: leaf gas exchange, quantum yield of chlorophyll a fluorescence, and relative contents of total chlorophyll (SPAD index. The experiment was conducted under a randomized block experimental design, in a split plot arrangement. In the plots, plants were exposed to different levels of water stress, by imposing potential crop evapotranspiration replacement levels equivalent to 100%, 80%, 60%, 40%, and 20%, whereas in subplots, plants were exposed to different levels of soil salinity (1.72, 6.25, 25.80, and 40.70 dS m - 1 . Physiological mechanisms were effectively limited when water deficit and salinity acted separately and/or together. Compared with soil salinity, water stress was more effective in reducing the measured physiological parameters. The magnitudes of the responses of plants to water supply and salinity depended on the intensity of stress and evaluation period. The physiological acclimation responses of plants were mainly related to stomatal regulation. The coconut tree has a number of physiological adjustment mechanisms that give the species partial tolerance to drought stress and/or salt, thereby enabling it to revegetate salinated areas, provided that its water requirements are at least partially met.
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Barber, N.A.; Milano, N.J.; Kiers, E.T.; Theis, N.; Bartolo, V.; Hazzard, R.V.; Adler, L.S.
2015-01-01
There is a widespread recognition that above- and below-ground organisms are linked through their interactions with host plants that span terrestrial subsystems. In addition to direct effects on plants, soil organisms such as root herbivores can indirectly alter interactions between plants and other
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Snoeren, T.A.L.; Mumm, R.; Poelman, E.H.; Yang, Y.; Pichersky, E.; Dicke, M.
2010-01-01
The indirect defense mechanisms of plants comprise the production of herbivore-induced plant volatiles that can attract natural enemies of plant attackers. One of the often emitted compounds after herbivory is methyl salicylate (MeSA). Here, we studied the importance of this caterpillar-induced
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Contribution of transposable elements in the plant's genome.
Sahebi, Mahbod; Hanafi, Mohamed M; van Wijnen, Andre J; Rice, David; Rafii, M Y; Azizi, Parisa; Osman, Mohamad; Taheri, Sima; Bakar, Mohd Faizal Abu; Isa, Mohd Noor Mat; Noor, Yusuf Muhammad
2018-07-30
Plants maintain extensive growth flexibility under different environmental conditions, allowing them to continuously and rapidly adapt to alterations in their environment. A large portion of many plant genomes consists of transposable elements (TEs) that create new genetic variations within plant species. Different types of mutations may be created by TEs in plants. Many TEs can avoid the host's defense mechanisms and survive alterations in transposition activity, internal sequence and target site. Thus, plant genomes are expected to utilize a variety of mechanisms to tolerate TEs that are near or within genes. TEs affect the expression of not only nearby genes but also unlinked inserted genes. TEs can create new promoters, leading to novel expression patterns or alternative coding regions to generate alternate transcripts in plant species. TEs can also provide novel cis-acting regulatory elements that act as enhancers or inserts within original enhancers that are required for transcription. Thus, the regulation of plant gene expression is strongly managed by the insertion of TEs into nearby genes. TEs can also lead to chromatin modifications and thereby affect gene expression in plants. TEs are able to generate new genes and modify existing gene structures by duplicating, mobilizing and recombining gene fragments. They can also facilitate cellular functions by sharing their transposase-coding regions. Hence, TE insertions can not only act as simple mutagens but can also alter the elementary functions of the plant genome. Here, we review recent discoveries concerning the contribution of TEs to gene expression in plant genomes and discuss the different mechanisms by which TEs can affect plant gene expression and reduce host defense mechanisms. Copyright © 2018 Elsevier B.V. All rights reserved.
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The Bacterial Pathogen Xylella fastidiosa Affects the Leaf Ionome of Plant Hosts during Infection
De La Fuente, Leonardo; Parker, Jennifer K.; Oliver, Jonathan E.; Granger, Shea; Brannen, Phillip M.; van Santen, Edzard; Cobine, Paul A.
2013-01-01
Xylella fastidiosa is a plant pathogenic bacterium that lives inside the host xylem vessels, where it forms biofilm believed to be responsible for disrupting the passage of water and nutrients. Here, Nicotiana tabacum was infected with X. fastidiosa, and the spatial and temporal changes in the whole-leaf ionome (i.e. the mineral and trace element composition) were measured as the host plant transitioned from healthy to diseased physiological status. The elemental composition of leaves was used as an indicator of the physiological changes in the host at a specific time and relative position during plant development. Bacterial infection was found to cause significant increases in concentrations of calcium prior to the appearance of symptoms and decreases in concentrations of phosphorous after symptoms appeared. Field-collected leaves from multiple varieties of grape, blueberry, and pecan plants grown in different locations over a four-year period in the Southeastern US showed the same alterations in Ca and P. This descriptive ionomics approach characterizes the existence of a mineral element-based response to X. fastidiosa using a model system suitable for further manipulation to uncover additional details of the role of mineral elements during plant-pathogen interactions. This is the first report on the dynamics of changes in the ionome of the host plant throughout the process of infection by a pathogen. PMID:23667547
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The bacterial pathogen Xylella fastidiosa affects the leaf ionome of plant hosts during infection.
Directory of Open Access Journals (Sweden)
Leonardo De La Fuente
Full Text Available Xylella fastidiosa is a plant pathogenic bacterium that lives inside the host xylem vessels, where it forms biofilm believed to be responsible for disrupting the passage of water and nutrients. Here, Nicotiana tabacum was infected with X. fastidiosa, and the spatial and temporal changes in the whole-leaf ionome (i.e. the mineral and trace element composition were measured as the host plant transitioned from healthy to diseased physiological status. The elemental composition of leaves was used as an indicator of the physiological changes in the host at a specific time and relative position during plant development. Bacterial infection was found to cause significant increases in concentrations of calcium prior to the appearance of symptoms and decreases in concentrations of phosphorous after symptoms appeared. Field-collected leaves from multiple varieties of grape, blueberry, and pecan plants grown in different locations over a four-year period in the Southeastern US showed the same alterations in Ca and P. This descriptive ionomics approach characterizes the existence of a mineral element-based response to X. fastidiosa using a model system suitable for further manipulation to uncover additional details of the role of mineral elements during plant-pathogen interactions. This is the first report on the dynamics of changes in the ionome of the host plant throughout the process of infection by a pathogen.
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Nutrient foraging strategies are associated with productivity and population growth in forest shrubs
Stone, Bram W. G.; Faillace, Cara A.; Lafond, Jonathan J.; Baumgarten, Joni M.; Mozdzer, Thomas J.; Dighton, John; Meiners, Scott J.; Grabosky, Jason C.; Ehrenfeld, Joan G.
2017-01-01
Background and Aims Temperate deciduous forest understoreys are experiencing widespread changes in community composition, concurrent with increases in rates of nitrogen supply. These shifts in plant abundance may be driven by interspecific differences in nutrient foraging (i.e. conservative vs. acquisitive strategies) and, thus, adaptation to contemporary nutrient loading conditions. This study sought to determine if interspecific differences in nutrient foraging could help explain patterns of shrub success and decline in eastern North American forests. Methods Using plants grown in a common garden, fine root traits associated with nutrient foraging were measured for six shrub species. Traits included the mean and skewness of the root diameter distribution, specific root length (SRL), C:N ratio, root tissue density, arbuscular mycorrhizal colonization and foraging precision. Above- and below-ground productivity were also determined for the same plants, and population growth rates were estimated using data from a long-term study of community dynamics. Root traits were compared among species and associations among root traits, measures of productivity and rates of population growth were evaluated. Key Results Species fell into groups having thick or thin root forms, which correspond to conservative vs. acquisitive nutrient foraging strategies. Interspecific variation in root morphology and tissue construction correlated with measures of productivity and rates of cover expansion. Of the four species with acquisitive traits, three were introduced species that have become invasive in recent decades, and the fourth was a weedy native. In contrast, the two species with conservative traits were historically dominant shrubs that have declined in abundance in eastern North American forests. Conclusions In forest understoreys of eastern North America, elevated nutrient availability may impose a filter on species success in addition to above-ground processes such as herbivory
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Phytophagous insect fauna tracks host plant responses to exotic grass invasion.
Almeida-Neto, Mário; Prado, Paulo I; Lewinsohn, Thomas M
2011-04-01
The high dependence of herbivorous insects on their host plants implies that plant invaders can affect these insects directly, by not providing a suitable habitat, or indirectly, by altering host plant availability. In this study, we sampled Asteraceae flower heads in cerrado remnants with varying levels of exotic grass invasion to evaluate whether invasive grasses have a direct effect on herbivore richness independent of the current disturbance level and host plant richness. By classifying herbivores according to the degree of host plant specialization, we also investigated whether invasive grasses reduce the uniqueness of the herbivorous assemblages. Herbivorous insect richness showed a unimodal relationship with invasive grass cover that was significantly explained only by way of the variation in host plant richness. The same result was found for polyphagous and oligophagous insects, but monophages showed a significant negative response to the intensity of the grass invasion that was independent of host plant richness. Our findings lend support to the hypothesis that the aggregate effect of invasive plants on herbivores tends to mirror the effects of invasive plants on host plants. In addition, exotic plants affect specialist insects differently from generalist insects; thus exotic plants affect not only the size but also the structural profile of herbivorous insect assemblages.
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Plant diversity and plant identity influence Fusarium communities in soil.
LeBlanc, Nicholas; Kinkel, Linda; Kistler, H Corby
2017-01-01
Fusarium communities play important functional roles in soil and in plants as pathogens, endophytes, and saprotrophs. This study tests how rhizosphere Fusarium communities may vary with plant species, changes in the diversity of the surrounding plant community, and soil physiochemical characteristics. Fusarium communities in soil associated with the roots of two perennial prairie plant species maintained as monocultures or growing within polyculture plant communities were characterized using targeted metagenomics. Amplicon libraries targeting the RPB2 locus were generated from rhizosphere soil DNAs and sequenced using pyrosequencing. Sequences were clustered into operational taxonomic units (OTUs) and assigned a taxonomy using the Evolutionary Placement Algorithm. Fusarium community composition was differentiated between monoculture and polyculture plant communities, and by plant species in monoculture, but not in polyculture. Taxonomic classification of the Fusarium OTUs showed a predominance of F. tricinctum and F. oxysporum as well of the presence of a clade previously only found in the Southern Hemisphere. Total Fusarium richness was not affected by changes in plant community richness or correlated with soil physiochemical characteristics. However, OTU richness within two predominant phylogenetic lineages within the genus was positively or negatively correlated with soil physiochemical characteristics among samples within each lineage. This work shows that plant species, plant community richness, and soil physiochemical characteristics may all influence the composition and richness of Fusarium communities in soil.
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Planning for Biogas Plant in Denmark
DEFF Research Database (Denmark)
Landt, Cristina C.; Gaarsmand, Regin; Palsberg, Aske
2016-01-01
This article is about establishing biogas in Denmark in the region of Zealand, the challenges that are related to this establishment and how to overcome this challenges. The article highlights three reasons for these challenges: 1) Regulation, 2) The municipal planning and 3) Involved various...... stakeholders. It investigates how these challenges affected the process and were overcome in the establishment of Solrod Biogas. In terms of ownership and biomass input, this biogas plant is unique compared to other Danish biogas plants. The biogas plant is based on organic by-products from local industries...... and seaweed. The plant solves an essential environmental issue for the municipality and citizens who were affected by the smell of rotten seaweed washed up in Koge Bay. The seaweed is used as input; this solves several problems at the same time. The method used to establish Solrod Biogas was an integrated...
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Composition of hydroponic medium affects thorium uptake by tobacco plants
Czech Academy of Sciences Publication Activity Database
Soudek, Petr; Kufner, Daniel; Petrová, Šárka; Mihaljevič, M.; Vaněk, Tomáš
2013-01-01
Roč. 92, č. 9 (2013), s. 1090-1098 ISSN 0045-6535 R&D Projects: GA MŠk LH12162; GA MŠk(CZ) LD13029; GA MPO FR-TI3/778 Institutional research plan: CEZ:AV0Z50380511 Keywords : Thorium * Plant uptake * Polyamines Subject RIV: DN - Health Impact of the Environment Quality Impact factor: 3.499, year: 2013
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Plant neighbour identity matters to belowground interactions under controlled conditions.
Armas, Cristina; Pugnaire, Francisco Ignacio
2011-01-01
Root competition is an almost ubiquitous feature of plant communities with profound effects on their structure and composition. Far beyond the traditional view that plants interact mainly through resource depletion (exploitation competition), roots are known to be able to interact with their environment using a large variety of mechanisms that may inhibit or enhance access of other roots to the resource or affect plant growth (contest interactions). However, an extensive analysis on how these contest root interactions may affect species interaction abilities is almost lacking. In a common garden experiment with ten perennial plant species we forced pairs of plants of the same or different species to overlap their roots and analyzed how belowground contest interactions affected plant performance, biomass allocation patterns, and competitive abilities under abundant resource supply. Our results showed that net interaction outcome ranged from negative to positive, affecting total plant mass and allocation patterns. A species could be a strong competitor against one species, weaker against another one, and even facilitator to a third species. This leads to sets of species where competitive hierarchies may be clear but also to groups where such rankings are not, suggesting that intransitive root interactions may be crucial for species coexistence. The outcome of belowground contest interactions is strongly dependent on neighbours' identity. In natural plant communities this conditional outcome may hypothetically help species to interact in non-hierarchical and intransitive networks, which in turn might promote coexistence.
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Plants used to treat skin diseases
Tabassum, Nahida; Hamdani, Mariya
2014-01-01
Skin diseases are numerous and a frequently occurring health problem affecting all ages from the neonates to the elderly and cause harm in number of ways. Maintaining healthy skin is important for a healthy body. Many people may develop skin diseases that affect the skin, including cancer, herpes and cellulitis. Some wild plants and their parts are frequently used to treat these diseases. The use of plants is as old as the mankind. Natural treatment is cheap and claimed to be safe. It is also suitable raw material for production of new synthetic agents. A review of some plants for the treatment of skin diseases is provided that summarizes the recent technical advancements that have taken place in this area during the past 17 years. PMID:24600196
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Dynamic simulation of operating cases and malfunctions of an IGCC power plant system
Energy Technology Data Exchange (ETDEWEB)
Koch, I.; Hannemann, F. [Siemens AG, Power Generation (KWU), Erlangen (Germany); Hoffmann, U. [Technische Univ. Clausthal, Clausthal-Zellerfeld (Germany). Inst. fuer Chemische Verfahrenstechnik
1999-07-01
Fully integrated IGCC plants consist of several units. This novel integration of various plant systems places stiff new requirements on power plant design, as prediction of operating and faulted behavior is made more difficult by many different interactions. This is especially the case for the gas turbine fuel system in an IGCC power plant, as it affects and is affected by all of the other major plant systems. (orig.)
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International Nuclear Information System (INIS)
Al-Safadi, B.; Nabulsi, I.
2001-08-01
Five cultivars of garlic, two explants, six callusing media, six regeneration media, two kinds of light and several doses of gamma irradiation were used to determine the best conditions for callus induction and plant regeneration from garlic tissue cultures. Also, some experiments were conducted to study the possibility to isolate protoplast and regenerate plants. The experiment showed that medium MS9 was good for regenerating plant directly from basal plate without going through callus phase. ANOVA exhibited significant differences among used cultivars in their ability to form callus. No significant difference was observed between 16 hr light and complete darkness in callus growth. However, appearance of callus was generally better on darkness. Cultivar varied in their ability to regenerate and interaction between cultivars and media was observed. Cultivar kisswany was the best in regeneration (38%) and medium MS47 was the best among used media (35%). Light type played a significant role in regeneration of plants where red light was much better than white light in inducing regeneration (68% vs 36%). ANOVA revealed significant effect of low doses of gamma irradiation on stimulation regeneration of plant whereas high doses prevented regeneration. Many experiments were conducted to isolate protoplast and regenerate plants. The best method for culturing was the droplet and the best conditions for incubation were complete darkness at 25 Degreed centigrade. This lead to formation of cell wall but no cell division was observed (author)
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Plant-phytopathogen interactions: bacterial responses to environmental and plant stimuli.
Leonard, Simon; Hommais, Florence; Nasser, William; Reverchon, Sylvie
2017-05-01
Plant pathogenic bacteria attack numerous agricultural crops, causing devastating effects on plant productivity and yield. They survive in diverse environments, both in plants, as pathogens, and also outside their hosts as saprophytes. Hence, they are confronted with numerous changing environmental parameters. During infection, plant pathogens have to deal with stressful conditions, such as acidic, oxidative and osmotic stresses; anaerobiosis; plant defenses; and contact with antimicrobial compounds. These adverse conditions can reduce bacterial survival and compromise disease initiation and propagation. Successful bacterial plant pathogens must detect potential hosts and also coordinate their possibly conflicting programs for survival and virulence. Consequently, these bacteria have a strong and finely tuned capacity for sensing and responding to environmental and plant stimuli. This review summarizes our current knowledge of the signals and genetic circuits that affect survival and virulence factor expression in three important and well-studied plant pathogenic bacteria with wide host ranges and the capacity for long-term environmental survival. These are: Ralstonia solanacerarum, a vascular pathogen that causes wilt disease; Agrobacterium tumefaciens, a biotrophic tumorigenic pathogen responsible for crown gall disease and Dickeya, a brute force apoplastic pathogen responsible for soft-rot disease. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.
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Germino, Matthew J.
2014-01-01
Alpine and subalpine plant species are of special interest in ecology and ecophysiology because they represent life at the climate limit and changes in their relative abundances can be a bellwether for climate-change impacts. Perennial life forms dominate alpine plant communities, and their form and function reflect various avoidance, tolerance, or resistance strategies to interactions of cold temperature, radiation, wind, and desiccation stresses that prevail in the short growing seasons common (but not ubiquitous) in alpine areas. Plant microclimate is typically uncoupled from the harsh climate of the alpine, often leading to substantially warmer plant temperatures than air temperatures recorded by weather stations. Low atmospheric pressure is the most pervasive, fundamental, and unifying factor for alpine environments, but the resulting decrease in partial pressure of CO2 does not significantly limit carbon gain by alpine plants. Factors such as tree islands and topographic features create strong heterogeneous mosaics of microclimate and snow cover that are reflected in plant community composition. Factors affecting tree establishment and growth and formation of treeline are key to understanding alpine ecology. Carbohydrate and other carbon storage, rapid development in a short growing season, and physiological function at low temperature are prevailing attributes of alpine plants. A major contemporary research theme asks whether chilling at alpine-treeline affects the ability of trees to assimilate the growth resources and particularly carbon needed for growth or whether the growth itself is limited by the alpine environment. Alpine areas tend to be among the best conserved, globally, yet they are increasingly showing response to a range of anthropogenic impacts, such as atmospheric deposition.
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Quality assurance organization for nuclear power plants
International Nuclear Information System (INIS)
1983-01-01
This Safety Guide provides requirements, recommendations and illustrative examples for structuring, staffing and documenting the organizations that perform activities affecting quality of a nuclear power plant. It also provides guidance on control of organization interfaces, and establishment of lines for direction, communication and co-ordination. The provisions of this Guide are applicable to all organizations participating in any of the constituent areas of activities affecting quality of a nuclear power plant, such as design, manufacture, construction, commissioning and operation
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Kostenko, O.; Grootemaat, Saskia S.; Van der Putten, W.H.; Bezemer, T.M.
2012-01-01
The diversity of plant community can greatly affect the abundance and diversity of arthropods associated to that community, but can also influence the composition or abundance of arthropods on individual plants growing in that community. We sampled arthropods and recorded plant size of individual
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Air pollution damage to plants
Energy Technology Data Exchange (ETDEWEB)
Daly, G T
1974-01-01
The effects of the most important air pollutants on plants are described in detail. The include: smoke and particulates, sulfur dioxide, fluorides, peroxyacetyl nitrate, nitrogen oxides, and ozone. An attempt is made to show that plant injury by air pollution can be recognized and evaluated in the presence of effects from insect, fungal, bacterial, viral pathogens and the symptoms of nutrient and enviromental stress. All plants are more or less affected by toxic gases and metals absorbed from the air. For each plant and each pollutant there is a critical concentration above which damage occurs, and below which growth is normal.
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Effects and mechanism of acid rain on plant chloroplast ATP synthase.
Sun, Jingwen; Hu, Huiqing; Li, Yueli; Wang, Lihong; Zhou, Qing; Huang, Xiaohua
2016-09-01
Acid rain can directly or indirectly affect plant physiological functions, especially photosynthesis. The enzyme ATP synthase is the key in photosynthetic energy conversion, and thus, it affects plant photosynthesis. To clarify the mechanism by which acid rain affects photosynthesis, we studied the effects of acid rain on plant growth, photosynthesis, chloroplast ATP synthase activity and gene expression, chloroplast ultrastructure, intracellular H(+) level, and water content of rice seedlings. Acid rain at pH 4.5 remained the chloroplast structure unchanged but increased the expression of six chloroplast ATP synthase subunits, promoted chloroplast ATP synthase activity, and increased photosynthesis and plant growth. Acid rain at pH 4.0 or less decreased leaf water content, destroyed chloroplast structure, inhibited the expression of six chloroplast ATP synthase subunits, decreased chloroplast ATP synthase activity, and reduced photosynthesis and plant growth. In conclusion, acid rain affected the chloroplast ultrastructure, chloroplast ATPase transcription and activity, and P n by changing the acidity in the cells, and thus influencing the plant growth and development. Finally, the effects of simulated acid rain on the test indices were found to be dose-dependent.
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Plant actin cytoskeleton re-modeling by plant parasitic nematodes.
Engler, Janice de Almeida; Rodiuc, Natalia; Smertenko, Andrei; Abad, Pierre
2010-03-01
The cytoskeleton is an important component of the plant's defense mechanism against the attack of pathogenic organisms. Plants however, are defenseless against parasitic root-knot and cyst nematodes and respond to the invasion by the development of a special feeding site that supplies the parasite with nutrients required for the completion of its life cycle. Recent studies of nematode invasion under treatment with cytoskeletal drugs and in mutant plants where normal functions of the cytoskeleton have been affected, demonstrate the importance of the cytoskeleton in the establishment of a feeding site and successful nematode reproduction. It appears that in the case of microfilaments, nematodes hijack the intracellular machinery that regulates actin dynamics and modulate the organization and properties of the actin filament network. Intervening with this process reduces the nematode infection efficiency and inhibits its life cycle. This discovery uncovers a new pathway that can be exploited for the protection of plants against nematodes.
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Induced mutations - a tool in plant research
International Nuclear Information System (INIS)
1981-01-01
These proceedings include 34 papers and 18 brief descriptions of poster presentations in the following areas as they are affected by induced mutations: advancement of genetics, plant evolution, plant physiology, plant parasites, plant symbioses, in vitro culture, gene ecology and plant breeding. Only a relatively small number of papers are of direct nuclear interest essentially in view of the mutations being induced by ionizing radiations. The papers of nuclear interest have been entered as separate and individual items of input
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Comparing Planting Tools for Container Longleaf Pine
Daniel J. Leduc; James D. Haywood; Shi-Jean Susana Sung
2011-01-01
We examined if compressing the soil to make a planting hole with a custom-built, solid round dibble versus coring the soil with a commercially available tube dibble influenced container-grown longleaf pine seedling development differently. Seven teen months after planting, the planting tool did not significantly affect root collar diameter, shoot or root mass, root-to-...
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Response of native insect communities to invasive plants.
Bezemer, T Martijn; Harvey, Jeffrey A; Cronin, James T
2014-01-01
Invasive plants can disrupt a range of trophic interactions in native communities. As a novel resource they can affect the performance of native insect herbivores and their natural enemies such as parasitoids and predators, and this can lead to host shifts of these herbivores and natural enemies. Through the release of volatile compounds, and by changing the chemical complexity of the habitat, invasive plants can also affect the behavior of native insects such as herbivores, parasitoids, and pollinators. Studies that compare insects on related native and invasive plants in invaded habitats show that the abundance of insect herbivores is often lower on invasive plants, but that damage levels are similar. The impact of invasive plants on the population dynamics of resident insect species has been rarely examined, but invasive plants can influence the spatial and temporal dynamics of native insect (meta)populations and communities, ultimately leading to changes at the landscape level.
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International Nuclear Information System (INIS)
Park, Jinkyun; Jeong, Kwangsup; Jung, Wondea
2005-01-01
In complex systems such as a nuclear and chemical plant, it is well known that the provision of understandable procedures that allow operators to clarify what needs to be done and how to do it is one of the requisites to secure their safety. As a previous study in providing understandable procedures, the step complexity (SC) measure that can quantify the complexity of procedural steps in emergency operating procedures (EOPs) of a nuclear power plant (NPP) was suggested. However, the necessity of additional complexity factors that can consider a cognitive aspect in evaluating the complexity of procedural steps is raised. To this end, the comparisons between operators' performance data measured by the form of a step performance time with their behavior in carrying out the prescribed activities of procedural steps are conducted in this study. As a result, two kinds of complexity factors (the abstraction level of knowledge and the level of engineering decision) that could affect an operator's cognitive burden are identified. Although a well-designed experiment is indispensable for confirming the appropriateness of the additional complexity factors, it is strongly believed that the change of operators' performance data can be more authentically explained if the additional complexity factors are taken into consideration
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Energy Technology Data Exchange (ETDEWEB)
Park, Jinkyun [Integrated Safety Assessment Division, Korea Atomic Energy Research Institute, P.O. Box 105, Duckjin-Dong, Yusong-Ku, Taejon 305-600 (Korea, Republic of)]. E-mail: kshpjk@kaeri.re.kr; Jeong, Kwangsup [Integrated Safety Assessment Division, Korea Atomic Energy Research Institute, P.O. Box 105, Duckjin-Dong, Yusong-Ku, Taejon 305-600 (Korea, Republic of); Jung, Wondea [Integrated Safety Assessment Division, Korea Atomic Energy Research Institute, P.O. Box 105, Duckjin-Dong, Yusong-Ku, Taejon 305-600 (Korea, Republic of)
2005-08-01
In complex systems such as a nuclear and chemical plant, it is well known that the provision of understandable procedures that allow operators to clarify what needs to be done and how to do it is one of the requisites to secure their safety. As a previous study in providing understandable procedures, the step complexity (SC) measure that can quantify the complexity of procedural steps in emergency operating procedures (EOPs) of a nuclear power plant (NPP) was suggested. However, the necessity of additional complexity factors that can consider a cognitive aspect in evaluating the complexity of procedural steps is raised. To this end, the comparisons between operators' performance data measured by the form of a step performance time with their behavior in carrying out the prescribed activities of procedural steps are conducted in this study. As a result, two kinds of complexity factors (the abstraction level of knowledge and the level of engineering decision) that could affect an operator's cognitive burden are identified. Although a well-designed experiment is indispensable for confirming the appropriateness of the additional complexity factors, it is strongly believed that the change of operators' performance data can be more authentically explained if the additional complexity factors are taken into consideration.
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Energy Technology Data Exchange (ETDEWEB)
Jinkyun Park; Kwangsup Jeong; Wondea Jung [Korea Atomic Energy Research Institute, Taejon (Korea). Integrated Safety Assessment Division
2005-08-15
In complex systems such as a nuclear and chemical plant, it is well known that the provision of understandable procedures that allow operators to clarify what needs to be done and how to do it is one of the requisites to secure their safety. As a previous study in providing understandable procedures, the step complexity (SC) measure that can quantify the complexity of procedural steps in emergency operating procedures (EOPs) of a nuclear power plant (NPP) was suggested. However, the necessity of additional complexity factors that can consider a cognitive aspect in evaluating the complexity of procedural steps is raised. To this end, the comparisons between operator' performance data measured by the form of a step performance time with their behavior in carrying out the prescribed activities of procedural steps are conducted in this study. As a result, two kinds of complexity factors (the abstraction level of knowledge and the level of engineering decision) that could affect an operator's cognitive burden are identified. Although a well-designed experiment is indispensable for confirming the appropriateness of the additional complexity factors, it is strongly believed that the change of operators' performance data can be more authentically explained if the additional complexity factors are taken into consideration. (author)
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Grutters, Bart; Pollux, B.J.A.; Verberk, W.C.E.P.; Bakker, E.S.
2015-01-01
Non-native species introductions are widespread and can affect ecosystem functioning by altering the structure of food webs. Invading plants often modify habitat structure, which may affect the suitability of vegetation as refuge and could thus impact predator-prey dynamics. Yet little is known
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Energy Technology Data Exchange (ETDEWEB)
Hashimoto, Risa; Inoue, Aki; Muramatsu, Yasuyuki [Gakushuin University, 1-5-1 Mejiro, Toshima-ku, Tokyo, 171-8588 (Japan); Matsuzaki, Hiroyuki [The University of Tokyo, Micro Analysis Laboratory, Tandem Accelerator, 2-11-16 Yayoi, Bunkyo-ku, Tokyo, 113-0032 (Japan)
2014-07-01
Okuma and Namie were considerably higher than the background values measured in Chiba and Niigata samples. The delta {sup 14}C values in the old leaves (grown before the accident) of Japanese cedar collected from Okuma and Namie were higher than those in the new leaves (grown after the accident). Since delta {sup 14}C values in the new leaves are similar to those in background samples collected from outside of Fukushima Prefecture. These results suggest that delta {sup 14}C values in plants grown near FDNPP were affected by {sup 14}C released from FDNPP, although the levels were not so high. It is not known whether {sup 14}C was absorbed as a gaseous form (CO{sub 2}) by plants or it was deposited as a particulate form. To examine this, we are planning to wash the contaminated cedar leaves with water for removing particulate matters deposited on the leaf surface. (authors)
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Directory of Open Access Journals (Sweden)
Tessa Vossen
Full Text Available Folk perceptions of health and illness include cultural bound syndromes (CBS, ailments generally confined to certain cultural groups or geographic regions and often treated with medicinal plants. Our aim was to compare definitions and plant use for CBS regarding child health in the context of the largest migration in recent human history: the trans-Atlantic slave trade. We compared definitions of four CBS (walk early, evil eye, atita and fontanels and associated plant use among three Afro-Surinamese populations and their African ancestor groups in Ghana, Bénin and Gabon. We expected plant use to be similar on species level, and assumed the majority to be weedy or domesticated species, as these occur on both continents and were probably recognized by enslaved Africans. Data were obtained by identifying plants mentioned during interviews with local women from the six different populations. To analyse differences and similarities in plant use we used Detrended Component Analysis (DCA and a Wald Chi-square test. Definitions of the four cultural bound syndromes were roughly the same on both continents. In total, 324 plant species were used. There was little overlap between Suriname and Africa: 15 species were used on two continents, of which seven species were used for the same CBS. Correspondence on family level was much higher. Surinamese populations used significantly more weedy species than Africans, but equal percentages of domesticated plants. Our data indicate that Afro-Surinamers have searched for similar plants to treat their CBS as they remembered from Africa. In some cases, they have found the same species, but they had to reinvent the largest part of their herbal pharmacopeia to treat their CBS using known plant families or trying out new species. Ideas on health and illness appear to be more resilient than the use of plants to treat them.
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Vossen, Tessa; Towns, Alexandra; Ruysschaert, Sofie; Quiroz, Diana; van Andel, Tinde
2014-01-01
Folk perceptions of health and illness include cultural bound syndromes (CBS), ailments generally confined to certain cultural groups or geographic regions and often treated with medicinal plants. Our aim was to compare definitions and plant use for CBS regarding child health in the context of the largest migration in recent human history: the trans-Atlantic slave trade. We compared definitions of four CBS (walk early, evil eye, atita and fontanels) and associated plant use among three Afro-Surinamese populations and their African ancestor groups in Ghana, Bénin and Gabon. We expected plant use to be similar on species level, and assumed the majority to be weedy or domesticated species, as these occur on both continents and were probably recognized by enslaved Africans. Data were obtained by identifying plants mentioned during interviews with local women from the six different populations. To analyse differences and similarities in plant use we used Detrended Component Analysis (DCA) and a Wald Chi-square test. Definitions of the four cultural bound syndromes were roughly the same on both continents. In total, 324 plant species were used. There was little overlap between Suriname and Africa: 15 species were used on two continents, of which seven species were used for the same CBS. Correspondence on family level was much higher. Surinamese populations used significantly more weedy species than Africans, but equal percentages of domesticated plants. Our data indicate that Afro-Surinamers have searched for similar plants to treat their CBS as they remembered from Africa. In some cases, they have found the same species, but they had to reinvent the largest part of their herbal pharmacopeia to treat their CBS using known plant families or trying out new species. Ideas on health and illness appear to be more resilient than the use of plants to treat them.
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Mathematical models for plant-herbivore interactions
Feng, Zhilan; DeAngelis, Donald L.
2017-01-01
Mathematical Models of Plant-Herbivore Interactions addresses mathematical models in the study of practical questions in ecology, particularly factors that affect herbivory, including plant defense, herbivore natural enemies, and adaptive herbivory, as well as the effects of these on plant community dynamics. The result of extensive research on the use of mathematical modeling to investigate the effects of plant defenses on plant-herbivore dynamics, this book describes a toxin-determined functional response model (TDFRM) that helps explains field observations of these interactions. This book is intended for graduate students and researchers interested in mathematical biology and ecology.
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Klein, Alexandra-Maria; Steffan-Dewenter, Ingolf; Tscharntke, Teja
2006-03-01
1. Human alteration of natural ecosystems to agroecosystems continues to accelerate in tropical countries. The resulting world-wide decline of rain forest causes a mosaic landscape, comprising simple and complex agroecosystems and patchily distributed rain forest fragments of different quality. Landscape context and agricultural management can be expected to affect both species diversity and ecosystem services by trophic interactions. 2. In Central Sulawesi, Indonesia, 24 agroforestry systems, differing in the distance to the nearest natural forest (0-1415 m), light intensity (37.5-899.6 W/m(-2)) and number of vascular plant species (7-40 species) were studied. Ten standardized trap nests for bees and wasps, made from reed and knotweed internodes, were exposed in each study site. Occupied nests were collected every month, over a period totalling 15 months. 3. A total of 13,617 brood cells were reared to produce adults of 14 trap-nesting species and 25 natural enemy species, which were mostly parasitoids. The total number of species was affected negatively by increasing distance from forest and increased with light intensity of agroforestry systems. The parasitoids in particular appeared to benefit from nearby forests. Over a 500-m distance, the number of parasitoid species decreased from eight to five, and parasitism rates from 12% to 4%. 4. The results show that diversity and parasitism, as a higher trophic interaction and ecosystem service, are enhanced by (i) improved connectivity of agroecosystems with natural habitats such as agroforestry adjacent to rain forest and (ii) management practices to increase light availability in agroforestry, which also enhances richness of flowering plants in the understorey.
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The diversity of beetle assemblages in different habitat types in Sabah, Malaysia.
Chung, A Y; Eggleton, P; Speight, M R; Hammond, P M; Chey, V K
2000-12-01
The diversity of beetle assemblages in different habitat types (primary forest, logged forest, acacia plantation and oil palm plantation) in Sabah, Malaysia was investigated using three different methods based on habitat levels (Winkler sampling, flight-interception-trapping and mist-blowing). The overall diversity was extremely high, with 1711 species recorded from only 8028 individuals and 81 families (115 family and subfamily groups). Different degrees of environmental changes had varying effects on the beetle species richness and abundance, with oil palm plantation assemblage being most severely affected, followed by acacia plantation and then logged forest. A few species became numerically dominant in the oil palm plantation. In terms of beetle species composition, the acacia fauna showed much similarity with the logged forest fauna, and the oil palm fauna was very different from the rest. The effects of environmental variables (number of plant species, sapling and tree densities, amount of leaf litter, ground cover, canopy cover, soil pH and compaction) on the beetle assemblage were also investigated. Leaf litter correlated with species richness, abundance and composition of subterranean beetles. Plant species richness, tree and sapling densities correlated with species richness, abundance and composition of understorey beetles while ground cover correlated only with the species richness and abundance of these beetles. Canopy cover correlated only with arboreal beetles. In trophic structure, predators represented more than 40% of the species and individuals. Environmental changes affected the trophic structure with proportionally more herbivores (abundance) but fewer predators (species richness and abundance) in the oil palm plantation. Biodiversity, conservation and practical aspects of pest management were also highlighted in this study.
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Plant physiology meets phytopathology: plant primary metabolism and plant-pathogen interactions.
Berger, Susanne; Sinha, Alok K; Roitsch, Thomas
2007-01-01
Phytopathogen infection leads to changes in secondary metabolism based on the induction of defence programmes as well as to changes in primary metabolism which affect growth and development of the plant. Therefore, pathogen attack causes crop yield losses even in interactions which do not end up with disease or death of the plant. While the regulation of defence responses has been intensively studied for decades, less is known about the effects of pathogen infection on primary metabolism. Recently, interest in this research area has been growing, and aspects of photosynthesis, assimilate partitioning, and source-sink regulation in different types of plant-pathogen interactions have been investigated. Similarly, phytopathological studies take into consideration the physiological status of the infected tissues to elucidate the fine-tuned infection mechanisms. The aim of this review is to give a summary of recent advances in the mutual interrelation between primary metabolism and pathogen infection, as well as to indicate current developments in non-invasive techniques and important strategies of combining modern molecular and physiological techniques with phytopathology for future investigations.
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Plant Evolution: A Manufacturing Network Perspective
DEFF Research Database (Denmark)
Yang, Cheng; Johansen, John; Boer, Harry
2009-01-01
Viewing them as portfolios of products and processes, we aim to address how plants evolve in the context of a manufacturing network and how the evolution of one plant impacts other plants in the same manufacturing network. Based on discussions of ten plants from three Danish companies, we identify...... two different trajectories. Together, these trajectories determine the evolution of a manufacturing network. Factors appearing to affect the two trajectories include competencies built up, transferred or acquired locally, market potential, performance considerations, local, situational factors...
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The importance of phenology in studies of plant-herbivore-parasitoid interactions
Fei, Minghui
2016-01-01
Thesis title: The importance of phenology in studies of plant-herbivore-parasitoid interactions Author: Minghui Fei Abstract As food resources of herbivorous insects, the quality and quantity of plants can directly affect the performance of herbivorous insects and indirectly affect
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Antagonistic interactions between plant competition and insect herbivory.
Schädler, Martin; Brandl, Roland; Haase, Josephine
2007-06-01
Interspecific competition between plants and herbivory by specialized insects can have synergistic effects on the growth and performance of the attacked host plant. We tested the hypothesis that competition between plants may also negatively affect the performance of herbivores as well as their top-down effect on the host plant. In such a case, the combined effects of competition and herbivory may be less than expected from a simple multiplicative response. In other words, competition and herbivory may interact antagonistically. In a greenhouse experiment, Poa annua was grown in the presence or absence of a competitor (either Plantago lanceolata or Trifolium repens), as well as with or without a Poa-specialist aphid herbivore. Both competition and herbivory negatively affected Poa growth. Competition also reduced aphid density on Poa. This effect could in part be explained by changes in the biomass and the nitrogen content of Poa shoots. In treatments with competitors, reduced aphid densities alleviated the negative effect of herbivory on above- and belowground Poa biomass. Hence, we were able to demonstrate an antagonistic interaction between plant-plant interspecific competition and herbivory. However, response indices suggested that antagonistic interactions between competition and herbivory were contingent on the identity of the competitor. We found the antagonistic effect only in treatments with T. repens as the competitor. We conclude that both competitor identity and the herbivore's ability to respond with changes in its density or activity to plant competition affect the magnitude and direction (synergistic vs. antagonistic) of the interaction between competition and herbivory on plant growth.
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40 CFR 60.540 - Applicability and designation of affected facilities.
2010-07-01
... (CONTINUED) AIR PROGRAMS (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for the Rubber Tire Manufacturing Industry § 60.540 Applicability and designation of affected... each of the following affected facilities in rubber tire manufacturing plants that commence...
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Human dose pathways of radionuclides in forests
International Nuclear Information System (INIS)
Rantavaara, A.
2009-01-01
Forest soil, understorey vegetation and trees are all sources of radionuclides and human radiation doses after contaminating atmospheric deposition. People are exposed to radiation externally from sources outside the body and internally via ingestion and inhalation of radionuclides. Understorey vegetation contributes to ingestion doses through berries, herbs, wild honey, mushrooms and game meat; also trees provide feed to terrestrial birds and big game. During stay in forests people are subject to external radiation from forest floor and overstorey, and they may inhale airborne radioactive aerosol or gaseous radionuclides in ground level air. In the early phase of contamination also resuspended radionuclides may add to the internal dose of people via inhalation. People in Nordic countries are most exposed to radiation via ingestion of radionuclides in wild foods. The distribution of radionuclides in forests is changed by environmental processes, and thereby also the significance of various dose pathways to humans will change with time. External exposure is received in living environment from contaminated stemwood used as building timber and for manufacturing of furniture and other wood products. The aim of this paper is to outline the significance of various human dose pathways of radionuclides in forests considering the public and workers in forestry and production of bioenergy. Examples on effective doses are given based on two historical events, atmospheric nuclear weapon tests (mostly in 1950's and in 1960's) and the Chernobyl nuclear power plant accident in 1986. (au)
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Human dose pathways of radionuclides in forests; Forests ecosystems
Energy Technology Data Exchange (ETDEWEB)
Rantavaara, A. (Radiation and Nuclear Safety Authority, Research and Environmental Surveillance, Helsinki (Finland))
2009-06-15
Forest soil, understorey vegetation and trees are all sources of radionuclides and human radiation doses after contaminating atmospheric deposition. People are exposed to radiation externally from sources outside the body and internally via ingestion and inhalation of radionuclides. Understorey vegetation contributes to ingestion doses through berries, herbs, wild honey, mushrooms and game meat; also trees provide feed to terrestrial birds and big game. During stay in forests people are subject to external radiation from forest floor and overstorey, and they may inhale airborne radioactive aerosol or gaseous radionuclides in ground level air. In the early phase of contamination also resuspended radionuclides may add to the internal dose of people via inhalation. People in Nordic countries are most exposed to radiation via ingestion of radionuclides in wild foods. The distribution of radionuclides in forests is changed by environmental processes, and thereby also the significance of various dose pathways to humans will change with time. External exposure is received in living environment from contaminated stemwood used as building timber and for manufacturing of furniture and other wood products. The aim of this paper is to outline the significance of various human dose pathways of radionuclides in forests considering the public and workers in forestry and production of bioenergy. Examples on effective doses are given based on two historical events, atmospheric nuclear weapon tests (mostly in 1950's and in 1960's) and the Chernobyl nuclear power plant accident in 1986. (au)
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Physiological integration affects growth form and competitive ability in clonal plants
Czech Academy of Sciences Publication Activity Database
Herben, Tomáš
2004-01-01
Roč. 18, - (2004), s. 493-520 ISSN 0269-7653 R&D Projects: GA ČR(CZ) GA206/02/0953 Institutional research plan: CEZ:AV0Z6005908 Keywords : competitive ability * Physiological integration * clonal plants Subject RIV: EF - Botanics Impact factor: 3.215, year: 2004
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DEFF Research Database (Denmark)
Hansen, Brian Brun; Kiil, Søren
2012-01-01
of impurities (0.002 M Al2F6; 50 g quartz/L; 0.02 M Al3+, and 0.040 M Mg2+) were investigated. In addition, slurry from a full-scale wet FGD plant, experiencing formation of flat shaped crystals and poor gypsum dewatering properties, was transferred to the pilot plant to test if the plant would now start...... to time. In this work, the particle size distribution, morphology, and filtration rate of wet FGD gypsum formed in a pilot-scale experimental setup, operated in forced oxidation mode, have been studied. The influence of holding tank residence time (10–408 h), solids content (30–169 g/L), and the presence...... to produce low quality gypsum. The crystals formed in the pilot plant, on the basis of the full-scale slurry did, however, show acceptable filtration rates and crystal morphologies closer to the prismatic crystals from after pilot plant experiments with demineralized water. The gypsum slurry filtration rates...
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Directory of Open Access Journals (Sweden)
Julie Chenot
2017-10-01
Full Text Available The Mediterranean basin is extremely vulnerable to climate change, and one of the areas most impacted by human water demand. Yet the green roofs increasingly created both for aesthetic reasons and to limit pollution and urban runoff are themselves very water-demanding. Successful green roof installation depends on the establishment of the vegetation, and the substrate is the key element: it conserves water, and provides the nutrients and physical support indispensable for plant growth. Since typical Mediterranean plant communities require no maintenance, this study seeks to develop techniques for creating maintenance- and watering-free horizontal green roofs for public or private buildings in a Mediterranean context. The innovative aspect of this study lies in creating two soil mixes, fine elements (clay and silt and coarse elements (pebbles of all sizes, in two different thicknesses, to assess vegetation development. Monitoring of substrate moisture was carried out and coupled with local rainfall measurements during summer and autumn. As expected, substrate moisture is mainly influenced by substrate depth (the deeper, the moister and composition (the finer the particles (clays and silts, the higher the moisture content. Vegetation cover impacts moisture to a lesser extent but is itself affected by the composition and depth of the substrates. These results are subsequently discussed with relation to the issue of sustainable green roofs in Mediterranean climates. Considering applications of our results, for an optimal colonization of a Mediterranean vegetation, a substrate thickness of 15 cm composed mainly of fine elements (75% clay-silt and 25% pebble-sand would be recommended in green roofs.
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Mohamed, Mahmoud S M; Saleh, Ahmed M; Abdel-Farid, Ibrahim B; El-Naggar, Sabry A
2017-09-01
Fusarium oxysporum, the causal agent of rot and wilt diseases, is one of the most detrimental phytopathogens for the productivity of many economic crops. The present study was conducted to evaluate the potentiality of some xerophytic plants as eco-friendly approach for management of F. oxysporum. Phenolic rich extracts from five plants namely: Horwoodia dicksoniae, Citrullus colocynthis, Gypsophila capillaris, Pulicaria incisa and Rhanterium epapposum were examined in vitro. The different extracts showed high variability in their phenolic and flavonoid contents as well as total antioxidant capacity. A strong positive correlation existed between the antifungal activity of the tested extracts and their contents of both total phenolics and flavonoids (r values are 0.91 and 0.82, respectively). Extract of P. incisa was the most effective in reducing the mycelial growth (IC 50 =0.92mg/ml) and inhibiting the activities of CMCase, pectinase, amylase and protease by 36, 42, 58 and 55%, respectively. The high performance liquid chromatography analysis of P. incisa extract revealed the presence of eight phenolic acids along with five polyphenolic compounds. The flavonol, quercetin and its glycosides rutin and quercetrin were the most abundant followed by the phenolic acids, t-cinnamic, caffeic, ferulic and vanillic. P. incisa extract not only affects the growth and hydrolases of F. oxysporum but also induces ultrastructure changes in the mycelium, as revealed by transmission electron microscopy. To our knowledge, this is the first study to investigate the mechanisms underlying the antifungal activity of P. incisa. Copyright © 2016 Elsevier Inc. All rights reserved.
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Biodiversity of Terrestrial Ecosystems in Tropical to Temperate Australia
Directory of Open Access Journals (Sweden)
Raymond L. Specht
2012-01-01
Full Text Available During the short period of annual foliage growth in evergreen plant communities, aerodynamic fluxes (frictional, thermal, evaporative in the atmosphere as it flows over and through a plant community determine the Foliage Projective Covers and leaf attributes in overstorey and understorey strata. The number of leaves produced on each vertical foliage shoot depends on available soil water and nutrients during this growth period. The area of all leaves exposed to solar radiation determines net photosynthetic fixation of the plant community throughout the year. In turn, the species richness (number of species per hectare of both plants and resident vertebrates is determined. The species richness of unicellular algae and small multicellular isopods in permanent freshwater lagoons in Northern Australia may possibly have been increased by radiation released from nearby uranium deposits. Evolution of new angiosperms probably occurred in refugia during periods of extreme drought. When favourable climates were restored, the vegetation expanded to result in high Gamma Biodiversity (number of plant species per region but with each major plant community having essentially the same species richness (number of plant species per hectare. The probable effects of pollution and Global Warming on biodiversity in Australian ecosystems, that experience seasonal drought, are discussed.
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Multi-modal sensor system for plant water stress assessment
Plant stress critically affects plant growth and causes significant loss of productivity and quality. When the plant is under water stress, it impedes photosynthesis and transpiration, resulting in changes in leaf color and temperature. Leaf discoloration in photosynthesis can be assessed by measu...
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BREEMAN, AM
The crustose tetrasporophyte of the red alga Acrosymphyton purpuriferum is a qualitative short-day plant in the formation of its tetrasporangia. The critical daylength for the response was determined in plants precultured in various long-day regimes [20:4, 18:6, 16:8 and 14:10 (L:D, h)]. There was a
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The growth and photosynthesis of Typha in oil sands process affected material and water
Energy Technology Data Exchange (ETDEWEB)
Foote, L. [Alberta Univ., Edmonton, AB (Canada); Hornung, J. [Petro-Canada, Calgary, AB (Canada)
2007-07-01
Aquatic plants such as cattail contribute substantially to the energy flow in wetlands. Since Typha (cattail) plants acquire and cycle carbon and nutrients through wetlands, their growth and recycling of captured nutrients are an important part of natural, healthy wetland ecosystems. Cattail are pervasive and satisfy many of the criteria to be used as indicators of wetland integrity. This study investigated if cattail growth and carbon accrual were influenced by oil sands process materials (OSPM) such as consolidated tailings (CT). The purpose was to facilitate land reclamation initiatives by evaluating the impact that constituents of oil sands process material have on aquatic plant growth. The study was conducted at Suncor's experimental trenches. Six lined basins were used, of which 3 were filled with natural water and 3 were filled with trench water. Cattail were planted in different growth medium combinations, including CT over CT; soil over soil; soil over CT; and soil over sterilized sand. All leaf lengths and widths were measured along with the photosynthesis of the leaves and root and plant biomass at planting and after 2-years growth. A larger leaf area was observed under oil sands process influence, which may indicate increased carbon accrual above ground. Leaf area data suggested that CT affected plants are quite productive. The study also indicated that oil sands affected water may reduce plant fitness, and therefore could influence the overall oil sands reclamation timelines. Conversely, cattail grown in soil capped process affected material had a much larger leaf area compared to those grown in soil capped sand, most likely due to the higher levels of ammonia in process affected material.
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Directory of Open Access Journals (Sweden)
Christine Hellmann
Full Text Available Understanding interactions between native and invasive plant species in field settings and quantifying the impact of invaders in heterogeneous native ecosystems requires resolving the spatial scale on which these processes take place. Therefore, functional tracers are needed that enable resolving the alterations induced by exotic plant invasion in contrast to natural variation in a spatially explicit way. 15N isoscapes, i.e., spatially referenced representations of stable nitrogen isotopic signatures, have recently provided such a tracer. However, different processes, e.g. water, nitrogen or carbon cycles, may be affected at different spatial scales. Thus multi-isotope studies, by using different functional tracers, can potentially return a more integrated picture of invader impact. This is particularly true when isoscapes are submitted to statistical methods suitable to find homogeneous subgroups in multivariate data such as cluster analysis. Here, we used model-based clustering of spatially explicit foliar δ15N and δ13C isoscapes together with N concentration of a native indicator species, Corema album, to map regions of influence in a Portuguese dune ecosystem invaded by the N2-fixing Acacia longifolia. Cluster analysis identified regions with pronounced alterations in N budget and water use efficiency in the native species, with a more than twofold increase in foliar N, and δ13C and δ15N enrichment of up to 2‰ and 8‰ closer to the invader, respectively. Furthermore, clusters of multiple functional tracers indicated a spatial shift from facilitation through N addition in the proximity of the invader to competition for resources other than N in close contact. Finding homogeneous subgroups in multi-isotope data by means of model-based cluster analysis provided an effective tool for detecting spatial structure in processes affecting plant physiology and performance. The proposed method can give an objective measure of the spatial extent
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Owners of nuclear power plants
Energy Technology Data Exchange (ETDEWEB)
Hudson, C.R.; White, V.S.
1996-11-01
Commercial nuclear power plants in this country can be owned by a number of separate entities, each with varying ownership proportions. Each of these owners may, in turn, have a parent/subsidiary relationship to other companies. In addition, the operator of the plant may be a different entity as well. This report provides a compilation on the owners/operators for all commercial power reactors in the United States. While the utility industry is currently experiencing changes in organizational structure which may affect nuclear plant ownership, the data in this report is current as of July 1996. The report is divided into sections representing different aspects of nuclear plant ownership.
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García, María J; García-Mateo, María J; Lucena, Carlos; Romera, Francisco J; Rojas, Carmen L; Alcántara, Esteban; Pérez-Vicente, Rafael
2014-01-01
In a previous work, it was shown that bicarbonate (one of the most important factors causing Fe chlorosis in Strategy I plants) can limit the expression of several genes involved in Fe acquisition. Hypoxia is considered another important factor causing Fe chlorosis, mainly on calcareous soils. However, to date it is not known whether hypoxia aggravates Fe chlorosis by affecting bicarbonate concentration or by specific negative effects on Fe acquisition. Results found in this work show that hypoxia, generated by eliminating the aeration of the nutrient solution, can limit the expression of several Fe acquisition genes in Fe-deficient Arabidopsis, cucumber and pea plants, like the genes for ferric reductases AtFRO2, PsFRO1 and CsFRO1; iron transporters AtIRT1, PsRIT1 and CsIRT1; H(+) -ATPase CsHA1; and transcription factors AtFIT, AtbHLH38, and AtbHLH39. Interestingly, the limitation of the expression of Fe-acquisition genes by hypoxia did not occur in the Arabidopsis ethylene constitutive mutant ctr1, which suggests that the negative effect of hypoxia is related to ethylene, an hormone involved in the upregulation of Fe acquisition genes. As for hypoxia, results obtained by applying bicarbonate to the nutrient solution suggests that ethylene is also involved in its negative effect, since ACC (1-aminocyclopropane-1-carboxylic acid; ethylene precursor) partially reversed the negative effect of bicarbonate on the expression of Fe acquisition genes. Taken together, the results obtained show that hypoxia and bicarbonate could induce Fe chlorosis by limiting the expression of Fe acquisition genes, probably because each factor negatively affects different steps of ethylene synthesis and/or signaling. © 2013 Scandinavian Plant Physiology Society.
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Plant reproduction is altered by simulated herbicide drift to constructed plant communities
Herbicide drift may have unintended impacts on native vegetation, adversely affecting structure and function of plant communities. However, these potential effects have been rarely studied or quantified. To determine potential ecological effects of herbicide drift, we construct...
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Agrobacterium -induced hypersensitive necrotic reaction in plant cells
African Journals Online (AJOL)
High necrosis and poor survival rate of target plant tissues are some of the major factors that affect the efficiency of Agrobacterium-mediated T-DNA transfer into plant cells. These factors may be the result of, or linked to, hypersensitive defense reaction in plants to Agrobacterium infection, which may involve the recognition ...
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Jansen, M.; Zuidema, P.A.; Anten, N.P.R.; Martínez-Ramos, M.
2012-01-01
1. Persistent variation in growth rate between individual plants can have strong effects on population dynamics as fast growers reach the reproductive size at an earlier age and thus potentially contribute more to population growth than slow growers. In tropical forests, such persistent growth
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Plant Age Affects Wound-Induced Senescense in Lactuca Sativa L
Witkowska, I.M.; Woltering, E.J.
2014-01-01
In the present study we investigated the performance of dark-stored wounded leaf discs and pieces (to some extent mimicking fresh-cut product) of Lactuca sativa L. in relation to the physiological maturity at harvest. We used two related genotypes, i.e. a green (cv. Troubadour) and a red butterhead (cv. Teodore) differing in their pigment levels. For both genotypes, senescence of the wounded (fresh-cut) tissue prepared from leaves of younger plants was significantly delayed compared to wounde...
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The knockdown of OsVIT2 and MIT affects iron localization in rice seed.
Bashir, Khurram; Takahashi, Ryuichi; Akhtar, Shamim; Ishimaru, Yasuhiro; Nakanishi, Hiromi; Nishizawa, Naoko K
2013-11-20
The mechanism of iron (Fe) uptake in plants has been extensively characterized, but little is known about how Fe transport to different subcellular compartments affects Fe localization in rice seed. Here, we discuss the characterization of a rice vacuolar Fe transporter 2 (OsVIT2) T-DNA insertion line (osvit2) and report that the knockdown of OsVIT2 and mitochondrial Fe transporter (MIT) expression affects seed Fe localization. osvit2 plants accumulated less Fe in their shoots when grown under normal or excess Fe conditions, while the accumulation of Fe was comparable to that in wild-type (WT) plants under Fe-deficient conditions. The accumulation of zinc, copper, and manganese also changed significantly in the shoots of osvit2 plants. The growth of osvit2 plants was also slow compared to that of WT plants. The concentration of Fe increased in osvit2 polished seeds. Previously, we reported that the expression of OsVIT2 was higher in MIT knockdown (mit-2) plants, and in this study, the accumulation of Fe in mit-2 seeds decreased significantly. These results suggest that vacuolar Fe trafficking is important for plant Fe homeostasis and distribution, especially in plants grown in the presence of excess Fe. Moreover, changes in the expression of OsVIT2 and MIT affect the concentration and localization of metals in brown rice as well as in polished rice seeds.
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Directory of Open Access Journals (Sweden)
Rajinder S Mann
Full Text Available Transmission of plant pathogens by insect vectors is a complex biological process involving interactions between the plant, insect, and pathogen. Pathogen-induced plant responses can include changes in volatile and nonvolatile secondary metabolites as well as major plant nutrients. Experiments were conducted to understand how a plant pathogenic bacterium, Candidatus Liberibacter asiaticus (Las, affects host preference behavior of its psyllid (Diaphorina citri Kuwayama vector. D. citri were attracted to volatiles from pathogen-infected plants more than to those from non-infected counterparts. Las-infected plants were more attractive to D. citri adults than non-infected plants initially; however after feeding, psyllids subsequently dispersed to non-infected rather than infected plants as their preferred settling point. Experiments with Las-infected and non-infected plants under complete darkness yielded similar results to those recorded under light. The behavior of psyllids in response to infected versus non-infected plants was not influenced by whether or not they were carriers of the pathogen. Quantification of volatile release from non-infected and infected plants supported the hypothesis that odorants mediate psyllid preference. Significantly more methyl salicylate, yet less methyl anthranilate and D-limonene, was released by infected than non-infected plants. Methyl salicylate was attractive to psyllids, while methyl anthranilate did not affect their behavior. Feeding on citrus by D. citri adults also induced release of methyl salicylate, suggesting that it may be a cue revealing location of conspecifics on host plants. Infected plants were characterized by lower levels of nitrogen, phosphorus, sulfur, zinc, and iron, as well as, higher levels of potassium and boron than non-infected plants. Collectively, our results suggest that host selection behavior of D. citri may be modified by bacterial infection of plants, which alters release of
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New handbook for standardised measurement of plant functional traits worldwide.
Perez-Harguindeguy, N.; Diaz, S.; Garnier, E.; Lavorel, S.; Poorter, H.; Jaureguiberry, P.; Bret-Harte, M.S.; Cornwell, W.K.; Craine, J.M.; Gurvich, D.E.; Urcelay, C.; Veneklaas, E.J.; Reich, P.B.; Poorter, L.; Wright, I.J.; Ray, P.; Enrico, L.; Pausas, J.G.; de Vos, A.C.; Buchmann, N.; Funes, G.; Quetier, F.; Hodgson, J.G.; Thompson, K.; Morgan, H.D.; ter Steege, H.; van der Heijden, M.G.A.; Sack, L.; Blonder, B.; Poschlod, P.; Vaieretti, M.V.; Conti, G.; Staver, A.C.; Aquino, S.; Cornelissen, J.H.C.
2013-01-01
Plant functional traits are the features (morphological, physiological, phenological) that represent ecological strategies and determine how plants respond to environmental factors, affect other trophic levels and influence ecosystem properties. Variation in plant functional traits, and trait
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Use of nondestructive evaluation methods to improve power plant availability
International Nuclear Information System (INIS)
Weber, R.M.
1985-01-01
On an ever-increasing basis, utilities are relying on nondestructive evaluation (NDE) as a management and planning tool. In addition to the conventional ASME Code and Technical Specification-required examinations, progressive utilities are utilizing NDE sampling programs to monitor existing conditions and search for potential situations affecting plant safety and reliability. Improved NDE detection and sizing procedures give management personnel the accurate information needed to make the ''go/no go'' decisions on repair programs which can significantly affect plant availability. As the burden of regulatory-imposed inspection requirements increases, plant personnel are increasingly cognizant that NDE is a significant factor in their plant's outage schedule. Whether an outage is scheduled or forced, NDE becomes part of each plant's program to assure the safety and reliability of its critical components. Knowledge and planning of NDE application is important because of the time expended in examination performance and subsequent data evaluation. Managers who are knowledgeable in NDE application can effectively improve plant availability by scheduling NDE as an integral part of their maintenance programs. Examination results can then be used in making decisions directly affecting availability
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Ectomycorrhizal activity as affected by soil liming
Energy Technology Data Exchange (ETDEWEB)
Andersson, Solbritt
1996-05-01
Acidification of the forest soils in southern Sweden due to atmospheric deposition has become evident during recent decades. To counteract further acidification, liming of forests in the most affected areas has been proposed. Most forest trees in the temperate and boreal forest ecosystems live in symbiosis with ectomycorrhizal fungi, and their uptake of mineral nutrients from the soil is greatly influenced by the symbiosis. In this thesis effects of liming on ectomycorrhiza have been studied in relation to effects on root colonization, fungal growth and nitrogen uptake. In field experiments the effects of liming on ectomycorrhizal colonization of root tips were variable, possibly due to different soil types and climatic variations. However, a changed mycorrhizal community structure could be detected. Laboratory studies also showed that the substrate may influence the outcome of lime applications; the nutrient status of the substrate had a marked effect on how mycelial growth was affected by liming. Under the experimental conditions used in the studies presented in this thesis, liming reduced the uptake of nitrogen and phosphorus by both mycorrhizal and non-mycorrhizal plants. The amount of extractable nitrogen and phosphorus in the peat was also reduced by liming. The latter could be due to either microbial or chemical immobilization. The lime induced decrease in nitrogen uptake was stronger in non-mycorrhizal plants than in mycorrhizal plants. Thus, the mycorrhizal plants had a higher ability to deal with the negative effects of liming on nitrogen availability. This was not the case for phosphorus. The lime induced decrease in phosphorus uptake was stronger for mycorrhizal plants, and in the highest lime treatment there was no significant difference between the mycorrhizal and the non-mycorrhizal spruce plants. 76 refs, 2 figs, 1 tab
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Hamdia, M. A; Shaddad, M. A. K.
2010-01-01
Several environmental factors adversely affect plant growth and development and final yield performance of a crop. Drought, salinity, nutrient imbalances (including mineral toxicities and deficiencies) and extremes of temperature are among the major environmental constraints to crop productivity worldwide. Development of crop plants with stress tolerance, however, requires, among others, knowledge of the physiological mechanisms and genetic controls of the contributing traits at different pla...
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Tahaei, Amirreza; Soleymani, Ali; Shams, Majid
2016-09-01
Reduced seed germination is among the most important factors adversely affecting crop stand and subsequent plant growth. Fennel (Foeniculum vulgare Mill) is an important medicinal plant with poor seed germination rate, occasionally. It is accordingly pertinent to find methods which can enhance fennel seed germination and remove the barriers of dormancy breaking. The present experiments studied the effects of two different priming (cold moist stratification and osmopriming) and 14 dormancy breaking techniques (hormonal, osmopriming, biopriming, chemical priming, and hydropriming) on the seed germination and seedling growth of two different fennel genotypes under growth chamber conditions. In the first and second experiment, the priming techniques including the time lengths of cold moist stratification (0, 15, 30, and 45 days) and the concentrations of polyethylene glycol 6000 (PEG6000, osmopriming at -0.99, -1.35, and -2.33 MPa) were used as the main plots. However, in both experiments, the dormancy breaking techniques and fennel genotypes were factorially combined and used as the subplots. Different seed- and seedling-related parameters including germination (%), plumule, radicle and seedling length, average germination time, rate and homogeneity of germination, and seed vigor index were determined. Both priming techniques were efficient on the enhancement of seed germination and seedling growth. Among the dormancy breaking techniques, Aminol Forte (biopriming), kadostim (biopriming), benzyl adenine + kinetin (biopriming), distilled water (hydropriming), gibberellin + kinetin (hormonal priming), and benzyl adenine + kinetin + gibberellin (biopriming) were the most effective ones. The related concentrations were equal to 100 mg/l, 10(-5) M, and 0.4 %. The fennel genotypes reacted significantly different under priming conditions. It is possible to enhance seed germination and seedling growth of fennel using priming and dormancy breaking
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How Fencing Affects the Soil Quality and Plant Biomass in the Grassland of the Loess Plateau.
Zeng, Quanchao; Liu, Yang; Xiao, Li; Huang, Yimei
2017-09-25
Overgrazing is a severe problem in several regions in Northwestern China and has caused serious land degradation. Secondary natural succession plays an important role in the accumulation of soil carbon and nitrogen contents. Estimating the effects of grazing exclusion on soil quality and plant diversity will improve our understanding of the succession process after overgrazing and promote judicious management of degraded pastures. This experiment was designed to measure soil properties and plant diversity following an age chronosequence of grasslands (ages ranged from one year, 12 years, 20 years, and 30 years) in Northwestern China. The results showed that continuous fencing resulted in a considerable increase in plant coverage, plant biomass (above- and below-ground biomass), and plant diversity, which can directly or indirectly improve the accumulation of soil organic carbon and total nitrogen content. The plant coverage and the above- and below-ground biomass linearly increased along the succession time, whereas soil organic C and N contents showed a significant decline in the first 12 years and, subsequently, a significant increase. The increased plant biomass caused an increase in soil organic carbon and soil total nitrogen. These results suggested that soil restoration and plant cover were an incongruous process. Generally, soil restoration is a slow process and falls behind vegetation recovery after grazing exclusion. Although the accumulation of soil C and N stocks needed a long term, vegetation restoration was a considerable option for the degraded grassland due to the significant increase of plant biomass, diversity, and soil C and N stocks. Therefore, fencing with natural succession should be considered in the design of future degraded pastures.
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Plant species and functional group combinations affect green roof ecosystem functions.
Lundholm, Jeremy; Macivor, J Scott; Macdougall, Zachary; Ranalli, Melissa
2010-03-12
Green roofs perform ecosystem services such as summer roof temperature reduction and stormwater capture that directly contribute to lower building energy use and potential economic savings. These services are in turn related to ecosystem functions performed by the vegetation layer such as radiation reflection and transpiration, but little work has examined the role of plant species composition and diversity in improving these functions. We used a replicated modular extensive (shallow growing- medium) green roof system planted with monocultures or mixtures containing one, three or five life-forms, to quantify two ecosystem services: summer roof cooling and water capture. We also measured the related ecosystem properties/processes of albedo, evapotranspiration, and the mean and temporal variability of aboveground biomass over four months. Mixtures containing three or five life-form groups, simultaneously optimized several green roof ecosystem functions, outperforming monocultures and single life-form groups, but there was much variation in performance depending on which life-forms were present in the three life-form mixtures. Some mixtures outperformed the best monocultures for water capture, evapotranspiration, and an index combining both water capture and temperature reductions. Combinations of tall forbs, grasses and succulents simultaneously optimized a range of ecosystem performance measures, thus the main benefit of including all three groups was not to maximize any single process but to perform a variety of functions well. Ecosystem services from green roofs can be improved by planting certain life-form groups in combination, directly contributing to climate change mitigation and adaptation strategies. The strong performance by certain mixtures of life-forms, especially tall forbs, grasses and succulents, warrants further investigation into niche complementarity or facilitation as mechanisms governing biodiversity-ecosystem functioning relationships in green
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Drivers of Productivity Trends in Cork Oak Woodlands over the Last 15 Years
Directory of Open Access Journals (Sweden)
Maria João Santos
2016-06-01
Full Text Available Higher biodiversity leads to more productive ecosystems which, in turn, supports more biodiversity. Ongoing global changes affect ecosystem productivity and, therefore, are expected to affect productivity-biodiversity relationships. However, the magnitude of these relationships may be affected by baseline biodiversity and its lifeforms. Cork oak (Quercus suber woodlands are a highly biodiverse Mediterranean ecosystem managed for cork extraction; as a result of this management cork oak woodlands may have both tree and shrub canopies, just tree and just shrub canopies, and just grasslands. Trees, shrubs, and grasses may respond differently to climatic variables and their combination may, therefore, affect measurements of productivity and the resulting productivity-biodiversity relationships. Here, we asked whether the relationship between productivity and climate is affected by the responses of trees, shrubs, and grasses in cork oak woodlands in Southern Portugal. To answer this question, we linked a 15-year time series of Enhanced Vegetation Index (EVI derived from Landsat satellites to micrometeorological data to assess the relationship between trends in EVI and climate. Between 2000 and 2013 we observed an overall decrease in EVI. However, EVI increased over cork oaks and decreased over shrublands. EVI trends were strongly positively related to changes in relative humidity and negatively related to temperature. The intra-annual EVI cycle of grasslands and sparse cork oak woodland without understorey (savannah-like ecosystem had higher variation than the other land-cover types. These results suggest that oaks and shrubs have different responses to changes in water availability, which can be either related to oak physiology, to oaks being either more resilient or having lagged responses to changes in climate, or to the fact that shrublands start senesce earlier than oaks. Our results also suggest that in the future EVI could improve because the
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Role of glucosinolates in insect-plant relationships and multitrophic interactions
Hopkins, R.J.; Dam, van N.M.; Loon, van J.J.A.
2009-01-01
Glucosinolates present classical examples of plant compounds affecting insect-plant interactions. They are found mainly in the family Brassicaceae, which includes several important crops. More than 120 different glucosinolates are known. The enzyme myrosinase, which is stored in specialized plant
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The co-occurrence of different antagonists on a plant can greatly affect infochemicals with ecological consequences for higher trophic levels. Here we investigated how the presence of a plant pathogen, the powdery mildew Erysiphe cruciferarum, on Brassica rapa affects 1) plant volatiles emitted in r...
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Mann, Rajinder S.; Ali, Jared G.; Hermann, Sara L.; Tiwari, Siddharth; Pelz-Stelinski, Kirsten S.; Alborn, Hans T.; Stelinski, Lukasz L.
2012-01-01
Transmission of plant pathogens by insect vectors is a complex biological process involving interactions between the plant, insect, and pathogen. Pathogen-induced plant responses can include changes in volatile and nonvolatile secondary metabolites as well as major plant nutrients. Experiments were conducted to understand how a plant pathogenic bacterium, Candidatus Liberibacter asiaticus (Las), affects host preference behavior of its psyllid (Diaphorina citri Kuwayama) vector. D. citri were attracted to volatiles from pathogen-infected plants more than to those from non-infected counterparts. Las-infected plants were more attractive to D. citri adults than non-infected plants initially; however after feeding, psyllids subsequently dispersed to non-infected rather than infected plants as their preferred settling point. Experiments with Las-infected and non-infected plants under complete darkness yielded similar results to those recorded under light. The behavior of psyllids in response to infected versus non-infected plants was not influenced by whether or not they were carriers of the pathogen. Quantification of volatile release from non-infected and infected plants supported the hypothesis that odorants mediate psyllid preference. Significantly more methyl salicylate, yet less methyl anthranilate and D-limonene, was released by infected than non-infected plants. Methyl salicylate was attractive to psyllids, while methyl anthranilate did not affect their behavior. Feeding on citrus by D. citri adults also induced release of methyl salicylate, suggesting that it may be a cue revealing location of conspecifics on host plants. Infected plants were characterized by lower levels of nitrogen, phosphorus, sulfur, zinc, and iron, as well as, higher levels of potassium and boron than non-infected plants. Collectively, our results suggest that host selection behavior of D. citri may be modified by bacterial infection of plants, which alters release of specific headspace
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Vaněk, Aleš; Grösslová, Zuzana; Mihaljevič, Martin; Trubač, Jakub; Ettler, Vojtěch; Teper, Leslaw; Cabala, Jerzy; Rohovec, Jan; Zádorová, Tereza; Penížek, Vít; Pavlů, Lenka; Holubík, Ondřej; Němeček, Karel; Houška, Jakub; Drábek, Ondřej; Ash, Christopher
2016-09-20
Here, for the first time, we report the thallium (Tl) isotope record in moderately contaminated soils with contrasting land management (forest and meadow soils), which have been affected by emissions from coal-fired power plants. Our findings clearly demonstrate that Tl of anthropogenic (high-temperature) origin with light isotope composition was deposited onto the studied soils, where heavier Tl (ε(205)Tl ∼ -1) naturally occurs. The results show a positive linear relationship (R(2) = 0.71) between 1/Tl and the isotope record, as determined for all the soils and bedrocks, also indicative of binary Tl mixing between two dominant reservoirs. We also identified significant Tl isotope variations within the products from coal combustion and thermo-desorption experiments with local Tl-rich coal pyrite. Bottom ash exhibited the heaviest Tl isotope composition (ε(205)Tl ∼ 0), followed by fly ash (ε(205)Tl between -2.5 and -2.8) and volatile Tl fractions (ε(205)Tl between -6.2 and -10.3), suggesting partial Tl isotope fractionations. Despite the evident role of soil processes in the isotope redistributions, we demonstrate that Tl contamination can be traced in soils and propose that the isotope data represent a possible tool to aid our understanding of postdepositional Tl dynamics in surface environments for the future.
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RNA regulatory elements and polyadenylation in plants
Directory of Open Access Journals (Sweden)
Arthur G. Hunt
2012-01-01
Full Text Available Alternative poly(A site choice (also known as alternative polyadenylation, or APA has the potential to affect gene expression in qualitative and quantitative ways. Alternative polyadenylation may affect as many as 82% of all expressed genes in a plant. The consequences of APA include the generation of transcripts with differing 3’-UTRs (and thus differing potential regulatory potential and of transcripts with differing protein-coding potential. Genome-wide studies of possible APA suggest a linkage with pre-mRNA splicing, and indicate a coincidence of and perhaps cooperation between RNA regulatory elements that affect splicing efficiency and the recognition of novel intronic poly(A sites. These studies also raise the possibility of the existence of a novel class of polyadenylation-related cis elements that are distinct from the well-characterized plant polyadenylation signal. Many potential APA events, however, have not been associated with identifiable cis elements. The present state of the field reveals a broad scope of APA, and also numerous opportunities for research into mechanisms that govern both choice and regulation of poly(A sites in plants.
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Bustos-Segura, Carlos; Poelman, Erik H; Reichelt, Michael; Gershenzon, Jonathan; Gols, Rieta
2017-01-01
Intraspecific plant diversity can modify the properties of associated arthropod communities and plant fitness. However, it is not well understood which plant traits determine these ecological effects. We explored the effect of intraspecific chemical diversity among neighbouring plants on the associated invertebrate community and plant traits. In a common garden experiment, intraspecific diversity among neighbouring plants was manipulated using three plant populations of wild cabbage that differ in foliar glucosinolates. Plants were larger, harboured more herbivores, but were less damaged when plant diversity was increased. Glucosinolate concentration differentially correlated with generalist and specialist herbivore abundance. Glucosinolate composition correlated with plant damage, while in polycultures, variation in glucosinolate concentrations among neighbouring plants correlated positively with herbivore diversity and negatively with plant damage levels. The results suggest that intraspecific variation in secondary chemistry among neighbouring plants is important in determining the structure of the associated insect community and positively affects plant performance. © 2016 The Authors. Ecology Letters published by CNRS and John Wiley & Sons Ltd.
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Sterck, F.J.; Duursma, R.A.; Pearcy, R.W.; Valladares, F.; Cieslak, M.; Weemstra, M.
2013-01-01
1.Shade tolerance can be defined as the light level at which plants can survive and possibly grow. This light level is referred to as the whole-plant light compensation point (LCP). The LCP depends on multiple leaf and architectural traits. We are still uncertain how often interspecific trait
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The future of integrated coal gasification combined cycle power plants
International Nuclear Information System (INIS)
Mueller, R.; Termuehlen, H.
1991-01-01
This paper examines the future of integrated coal gasification combined cycle (IGCC) power plants as affected by various technical, economical and environmental trends in power generation. The topics of the paper include a description of natural gas-fired combined cycle power plants, IGCC plants, coal gasifier concepts, integration of gasifiers into combined cycle power plants, efficiency, environmental impacts, co-products of IGCC power plants, economics of IGCC power plants, and a review of IGCC power plant projects
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The bacterial microbiomes of citrus plants in response to ‘Candidatus Liberibacter asiaticus’ (Las)-infection and zinc treatments were deciphered by Phylochip-based metagenomics. The results indicated that 5,475 of over 50,000 known Operational Taxonomic Units (OTUs) in 52 phyla were detected in cit...
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Directory of Open Access Journals (Sweden)
Lucie Hemrová
Full Text Available Field translocation experiments (i.e., the introduction of seeds or seedlings of different species into different localities are commonly used to study habitat associations of species, as well as factors limiting species distributions and local abundances. Species planted or sown in sites where they naturally occur are expected to perform better or equally well compared to sites at which they do not occur or are rare. This, however, contrasts with the predictions of the Janzen-Connell hypothesis and commonly reported intraspecific negative plant-soil feedback. The few previous studies indicating poorer performance of plants at sites where they naturally occur did not explore the mechanisms behind this pattern.In this study, we used field translocation experiments established using both seeds and seedlings to study the determinants of local abundance of four dominant species in grasslands. To explore the possible effects of intraspecific negative plant-soil feedback on our results, we tested the effect of local species abundance on the performance of the plants in the field experiment. In addition, we set up a garden experiment to explore the intensity of intraspecific as well as interspecific feedback between the dominants used in the experiment.In some cases, the distribution and local abundances of the species were partly driven by habitat conditions at the sites, and species performed better at their own sites. However, the prevailing pattern was that the local dominants performed worse at sites where they naturally occur than at any other sites. Moreover, the success of plants in the field experiment was lower in the case of higher intraspecific abundance prior to experimental setup. In the garden feedback experiment, two of the species performed significantly worse in soils conditioned by their species than in soils conditioned by the other species. In addition, the performance of the plants was significantly correlated between the two
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Directory of Open Access Journals (Sweden)
Denis Herisson da Silva
2008-12-01
Full Text Available The cultivation of oleaginous plants like the castor bean guarantees employment for agricultural families and can contribute in energy and chemical sectors, especially in the northeastern semi-arid regions of Brazil. Boron (B deficiency is a widespread nutritional disorder despite the fact that various anthropogenic sources with high B content may increase soil B to toxic levels for plants. The present study was designed to investigate the ultrastructural effects of boron deficiency and toxicity on castor bean plants which were grown under greenhouse condition using plastic containers with 10 L of nutrient solution. Boron treatments comprised: control (no B; 0.27 mg L-1, 5.40 mg L-1 B pots (one plant per pot, tested in a completely randomized design with three replicates. The dry matter of all plant parts and B concentration were determined. Cellular ultrastructure was evaluated by transmission and scanning electron microscopy on samples of leaves and petioles. Dry matter yield was affected by the B absence treatment but there was no difference for the 5.4 mg L-1 B (toxic conditions treatment. A marginal leaf burn at edge and tips of oldest leaves and absence of starch granules in chloroplasts were noted for the B toxicity treatment. The deformation of the youngest leaves, the death of the apical meristem as well as the swelling of the middle lamella, absence of starch granules in chloroplasts and petiole vessels untidily were observed in the B absent treatment. It is concluded that the production and development of castor bean plants is affected by boron deficiency, but not for boron toxicity conditions.A mamoneira é uma oleaginosa com grande potencial para a geração de renda na agricultura familiar e para produção de matéria prima para a indústria química e setor energético brasileiro, especialmente em regiões do semi-árido nordestino. A deficiência de boro (B ocorre de forma generalizada no Brasil e a aplicação excessiva deste
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Climate change driven plant-metal-microbe interactions.
Rajkumar, Mani; Prasad, Majeti Narasimha Vara; Swaminathan, Sandhya; Freitas, Helena
2013-03-01
Various biotic and abiotic stress factors affect the growth and productivity of crop plants. Particularly, the climatic and/or heavy metal stress influence various processes including growth, physiology, biochemistry, and yield of crops. Climatic changes particularly the elevated atmospheric CO₂ enhance the biomass production and metal accumulation in plants and help plants to support greater microbial populations and/or protect the microorganisms against the impacts of heavy metals. Besides, the indirect effects of climatic change (e.g., changes in the function and structure of plant roots and diversity and activity of rhizosphere microbes) would lead to altered metal bioavailability in soils and concomitantly affect plant growth. However, the effects of warming, drought or combined climatic stress on plant growth and metal accumulation vary substantially across physico-chemico-biological properties of the environment (e.g., soil pH, heavy metal type and its bio-available concentrations, microbial diversity, and interactive effects of climatic factors) and plant used. Overall, direct and/or indirect effects of climate change on heavy metal mobility in soils may further hinder the ability of plants to adapt and make them more susceptible to stress. Here, we review and discuss how the climatic parameters including atmospheric CO₂, temperature and drought influence the plant-metal interaction in polluted soils. Other aspects including the effects of climate change and heavy metals on plant-microbe interaction, heavy metal phytoremediation and safety of food and feed are also discussed. This review shows that predicting how plant-metal interaction responds to altering climatic change is critical to select suitable crop plants that would be able to produce more yields and tolerate multi-stress conditions without accumulating toxic heavy metals for future food security. Copyright © 2012 Elsevier Ltd. All rights reserved.
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Native and exotic earthworms affect orchid seed loss
McCormick, Melissa K.; Parker, Kenneth L.; Szlavecz, Katalin; Whigham, Dennis F.
2013-01-01
Non-native earthworms have invaded ecosystems around the world but have recently received increased attention as they invaded previously earthworm-free habitats in northern North America. Earthworms can affect plants by ingesting seeds and burying them in the soil. These effects can be negative or positive but are expected to become increasingly negative with decreasing seed size. Orchids have some of the smallest seeds of any plants, so we hypothesized that earthworm consumption of seeds wou...
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Plant species richness regulates soil respiration through changes in productivity.
Dias, André Tavares Corrêa; van Ruijven, Jasper; Berendse, Frank
2010-07-01
Soil respiration is an important pathway of the C cycle. However, it is still poorly understood how changes in plant community diversity can affect this ecosystem process. Here we used a long-term experiment consisting of a gradient of grassland plant species richness to test for effects of diversity on soil respiration. We hypothesized that plant diversity could affect soil respiration in two ways. On the one hand, more diverse plant communities have been shown to promote plant productivity, which could increase soil respiration. On the other hand, the nutrient concentration in the biomass produced has been shown to decrease with diversity, which could counteract the production-induced increase in soil respiration. Our results clearly show that soil respiration increased with species richness. Detailed analysis revealed that this effect was not due to differences in species composition. In general, soil respiration in mixtures was higher than would be expected from the monocultures. Path analysis revealed that species richness predominantly regulates soil respiration through changes in productivity. No evidence supporting the hypothesized negative effect of lower N concentration on soil respiration was found. We conclude that shifts in productivity are the main mechanism by which changes in plant diversity may affect soil respiration.
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Dawes, Melissa A; Hagedorn, Frank; Handa, Ira Tanya; Streit, Kathrin; Ekblad, Alf; Rixen, Christian; Körner, Christian; Hättenschwiler, Stephan
2013-03-01
We evaluated the impacts of elevated CO2 in a treeline ecosystem in the Swiss Alps in a 9-year free-air CO2 enrichment (FACE) study. We present new data and synthesize plant and soil results from the entire experimental period. Light-saturated photosynthesis (A max) of ca. 35-year-old Larix decidua and Pinus uncinata was stimulated by elevated CO2 throughout the experiment. Slight down-regulation of photosynthesis in Pinus was consistent with starch accumulation in needle tissue. Above-ground growth responses differed between tree species, with a 33 % mean annual stimulation in Larix but no response in Pinus. Species-specific CO2 responses also occurred for abundant dwarf shrub species in the understorey, where Vaccinium myrtillus showed a sustained shoot growth enhancement (+11 %) that was not apparent for Vaccinium gaultherioides or Empetrum hermaphroditum. Below ground, CO2 enrichment did not stimulate fine root or mycorrhizal mycelium growth, but increased CO2 effluxes from the soil (+24 %) indicated that enhanced C assimilation was partially offset by greater respiratory losses. The dissolved organic C (DOC) concentration in soil solutions was consistently higher under elevated CO2 (+14 %), suggesting accelerated soil organic matter turnover. CO2 enrichment hardly affected the C-N balance in plants and soil, with unaltered soil total or mineral N concentrations and little impact on plant leaf N concentration or the stable N isotope ratio. Sustained differences in plant species growth responses suggest future shifts in species composition with atmospheric change. Consistently increased C fixation, soil respiration and DOC production over 9 years of CO2 enrichment provide clear evidence for accelerated C cycling with no apparent consequences on the N cycle in this treeline ecosystem.
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Pounsin, Grace; Wahab, Nur Syahirah; Roslan, Azuan; Zahidin, Muhamad Aidil; Pesiu, Elizabeth; Tamrin, Nur Aida Md; Abdullah, M T
2018-03-01
A study of the bat diversity was conducted in Hulu Terengganu dipterocarp forest and Setiu Wetland Beach Ridges Interspersed with Swales (BRIS) forest in Terengganu, to study the species diversity, composition and stratification of fruit bats from the understorey to the forest canopy. Mist nets were set up at the understorey, sub-canopy and canopy layer while harp traps were set up at the understorey layer. We recorded 170 individuals from six families' compromised 21 species from Hulu Terengganu dipterocarp forests and four species from Setiu Wetland BRIS forests throughout the sampling period. Megaerops ecaudatus and Cynopterus brachyotis were the most dominant species in Hulu Terengganu dipterocarp forest and Setiu Wetland BRIS forests. Our study also recorded two species with new distributional records for the east coast of Peninsular Malaysia, namely, Rhinolophus chiewkweeae and Chaerephon johorensis in Hulu Terengganu dipterocarp forests. Potential factors that might influence the results were in terms of the canopy covers, the structural complexity of canopy, food availability and spatial characteristics. This study was able to increase the knowledge on the species diversity and composition of bats in Hulu Terengganu dipterocarp forest and Setiu Wetland BRIS forest, thus, further aid in the effort of bat conservation in both areas.
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Phytoplasmas: bacteria that manipulate plants and insects.
Hogenhout, Saskia A; Oshima, Kenro; Ammar, El-Desouky; Kakizawa, Shigeyuki; Kingdom, Heather N; Namba, Shigetou
2008-07-01
Superkingdom Prokaryota; Kingdom Monera; Domain Bacteria; Phylum Firmicutes (low-G+C, Gram-positive eubacteria); Class Mollicutes; Candidatus (Ca.) genus Phytoplasma. Ca. Phytoplasma comprises approximately 30 distinct clades based on 16S rRNA gene sequence analyses of approximately 200 phytoplasmas. Phytoplasmas are mostly dependent on insect transmission for their spread and survival. The phytoplasma life cycle involves replication in insects and plants. They infect the insect but are phloem-limited in plants. Members of Ca. Phytoplasma asteris (16SrI group phytoplasmas) are found in 80 monocot and dicot plant species in most parts of the world. Experimentally, they can be transmitted by approximately 30, frequently polyphagous insect species, to 200 diverse plant species. In plants, phytoplasmas induce symptoms that suggest interference with plant development. Typical symptoms include: witches' broom (clustering of branches) of developing tissues; phyllody (retrograde metamorphosis of the floral organs to the condition of leaves); virescence (green coloration of non-green flower parts); bolting (growth of elongated stalks); formation of bunchy fibrous secondary roots; reddening of leaves and stems; generalized yellowing, decline and stunting of plants; and phloem necrosis. Phytoplasmas can be pathogenic to some insect hosts, but generally do not negatively affect the fitness of their major insect vector(s). In fact, phytoplasmas can increase fecundity and survival of insect vectors, and may influence flight behaviour and plant host preference of their insect hosts. The most common practices are the spraying of various insecticides to control insect vectors, and removal of symptomatic plants. Phytoplasma-resistant cultivars are not available for the vast majority of affected crops.
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International Nuclear Information System (INIS)
Webster, S.A.; Finnicum, D.J.
1985-01-01
Surveillances required to be conducted by a plant's Technical Specifications have resulted in plant shutdowns and lost availability. This paper looks at shutdowns which have occurred due to required surveillance testing and insufficient repair time allowed by Technical Specifications. A loss of plant availability of almost 3% per plant year was found for U.S. pressurized water reactors during the five year period, 1979 to 1984. This figure excludes major problems which required plant shutdown whether or not mandated by the Technical Specifications. In addition to their affect on availability, such shutdowns can add to the challenges to plant safety systems and can affect plant aging by increasing the thermal cycles on plant components
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Directory of Open Access Journals (Sweden)
Meredith Root-Bernstein
2014-12-01
Full Text Available Indicator species could help to compensate for a shortfall of knowledge about the diversity and distributions of undersampled and cryptic species. This paper provides background knowledge about the ecological interactions that affect and are affected by herbaceous diversity in central Chile, as part of the indicator species selection process. We focus on the ecosystem engineering role of small mammals, primarily the degu Octodon degus. We also consider the interacting effects of shrubs, trees, avian activity, livestock, slope, and soil quality on herbaceous communities in central Chile. We sampled herbaceous diversity on a private landholding characterized by a mosaic of savanna, grassland and matorral, across a range of degu disturbance intensities. We find that the strongest factors affecting endemic herbaceous diversity are density of degu runways, shrub cover and avian activity. Our results show that the degu, a charismatic and easily identifiable and countable species, could be used as an indicator species to aid potential conservation actions such as private protected area uptake. We map areas in central Chile where degus may indicate endemic plant diversity. This area is larger than expected, and suggests that significant areas of endemic plant communities may still exist, and should be identified and protected. Keywords: Cryptic species, Diversity, Endemic, Indicator species, Octodon degus, Plant
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Knobová, Pavlína
2017-01-01
Intraspecific plant-soil feedback is a relationship in which plant affects the composition of the soil and such modified soil affects growth of the same plant species. This relationship and its intensity may be linked with plant dominance and invasiveness. Dominant species can alter the composition of the soil in their favor and thus show positive intraspecific plant-soil feedback. As the invasive species are commonly being dominant in their new environment, it can be expected that intraspeci...
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Effect of oil spills on coastal power plants, refineries, and desalination plants
International Nuclear Information System (INIS)
Kiefer, C.; Mussali, Y.
1992-01-01
Major oil spills such as those experienced in the Gulf War, in Alaska, and in the Gulf of Mexico have raised concern for the protection of coastal facilities which use seawater for cooling or process purposes such as power stations, refineries, and desalination plants. Because of the availability of large quantities of cooling water, many power stations and refineries are located along the coastline in the United States and throughout the world. In addition, many countries in the Middle East, the Caribbean, and other areas of the world depend on desalination plants located along the coast for the vital supply of drinking water. The objective of this paper is to determine the levels of oil contamination which will adversely affect plant performance or result in damage to specific plant equipment such as condensers, heat exchangers, pumps, screens, water treatment equipment, and other vital water handling mechanisms
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Sources of Verticillium dahliae affecting lettuce.
Atallah, Zahi K; Maruthachalam, Karunakaran; Subbarao, Krishna V
2012-11-01
ABSTRACT Since 1995, lettuce in coastal California, where more than half of the crop in North America is grown, has consistently suffered from severe outbreaks of Verticillium wilt. The disease is confined to this region, although the pathogen (Verticillium dahliae) and the host are present in other crop production regions in California. Migration of the pathogen with infested spinach seed was previously documented, but the geographic sources of the pathogen, as well as the impact of lettuce seed sparsely infested with V. dahliae produced outside coastal California on the pathogen population in coastal California remain unclear. Population analyses of V. dahliae were completed using 16 microsatellite markers on isolates from lettuce plants in coastal California, infested lettuce seed produced in the neighboring Santa Clara Valley of California, and spinach seed produced in four major spinach seed production regions: Chile, Denmark, the Netherlands, and the United States (Washington State). California produces 80% of spinach in the United States and all seed planted with the majority infested by V. dahliae comes from the above four sources. Three globally distributed genetic populations were identified, indicating sustained migration among these distinct geographic regions with multiple spinach crops produced each year and repeated every year in coastal California. The population structure of V. dahliae from coastal California lettuce plants was heavily influenced by migration from spinach seed imported from Denmark and Washington. Conversely, the sparsely infested lettuce seed had limited or no contribution to the Verticillium wilt epidemic in coastal California. The global trade in plant and seed material is likely contributing to sustained shifts in the population structure of V. dahliae, affecting the equilibrium of native populations, and likely affecting disease epidemiology.
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Narbona, Eduardo; Dirzo, Rodolfo
2010-08-01
Monoecious plants have the capacity to allocate resources separately to male and female functions more easily than hermaphrodites. This can be advantageous against environmental stresses such as leaf herbivory. However, studies showing effects of herbivory on male and female functions and on the interaction with the plant's pollinators are limited, particularly in tropical plants. Here, the effects of experimental defoliation were examined in the monoecious shrub Croton suberosus (Euphorbiaceae), a wasp-pollinated species from a Mexican tropical dry forest. Three defoliation treatments were applied: 0 % (control), 25 % (low) or 75 % (high) of plant leaf area removed. Vegetative (production of new leaves) and reproductive (pistillate and staminate flower production, pollen viability, nectar production, fruit set, and seed set) performance variables, and the abundance and activity of floral visitors were examined. Defoliated plants overcompensated for tissue loss by producing more new leaves than control plants. Production of staminate flowers gradually decreased with increasing defoliation and the floral sex ratio (staminate : pistillate flowers) was drastically reduced in high-defoliation plants. In contrast, female reproductive performance (pistillate flower production, fruit set and seed set) and pollinator visitation and abundance were not impacted by defoliation. The asymmetrical effects of defoliation on male and female traits of C. suberosus may be due to the temporal and spatial flexibility in the allocation of resources deployed by monoecious plants. We posit that this helps to maintain the plant's pollination success in the face of leaf herbivory stress.
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Can iron plaque affect Sb(III) and Sb(V) uptake by plants under hydroponic conditions
Ji, Ying; Lenz, Markus; Lenz, Markus; Schulin, Rainer; Tandy, Susan
2018-01-01
Antimony (Sb) contamination of soils is of concern due to h uman activities such as recycling of Sb containing Pb acid batteries, shooting and mining. However Sb uptake by plants is poorly documented, especially when plants are growing on waterlogged soils and iron plaques form on their roots. The
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Biology and Epidemiology of Venturia Species Affecting Fruit Crops: A Review
Directory of Open Access Journals (Sweden)
Elisa González-Domínguez
2017-09-01
Full Text Available The fungal genus Venturia Sacc. (anamorph Fusicladium Bonord. includes plant pathogens that cause substantial economic damage to fruit crops worldwide. Although Venturia inaequalis is considered a model species in plant pathology, other Venturia spp. also cause scab on other fruit trees. Relative to the substantial research that has been conducted on V. inaequalis and apple scab, little research has been conducted on Venturia spp. affecting other fruit trees. In this review, the main characteristics of plant-pathogenic species of Venturia are discussed with special attention to V. inaequalis affecting apple, V. pyrina affecting European pear, V. nashicola affecting Asian pear, V. carpophila affecting peach and almond, Fusicladium oleagineum affecting olive, F. effusum affecting pecan, and F. eriobotryae affecting loquat. This review has two main objectives: (i to identify the main gaps in our knowledge regarding the biology and epidemiology of Venturia spp. affecting fruit trees; and (ii to identify similarities and differences among these Venturia spp. in order to improve disease management. A thorough review has been conducted of studies regarding the phylogenetic relationships, host ranges, biologies, and epidemiologies of Venturia spp. A multiple correspondence analysis (CA has also been performed on the main epidemiological components of these Venturia spp. CA separated the Venturia spp. into two main groups, according to their epidemiological behavior: the first group included V. inaequalis, V. pyrina, V. nashicola, and V. carpophila, the second F. oleagineum and F. eriobotryae, with F. effusum having an intermediate position. This review shows that Venturia spp. affecting fruit trees are highly host-specific, and that important gaps in understanding the life cycle exist for some species, including V. pyrina; gaps include pseudothecia formation, ascospore and conidia germination, and mycelial growth. Considering the epidemiological
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Santiago, Graziele Silva; Zurlo, Luana Fonseca; Ribas, Carla Rodrigues; Carvalho, Rafaela Pereira; Alves, Guilherme Pereira; Carvalho, Mariana Comanucci Silva; Souza, Brígida
2017-01-01
Ant-aphid interactions may affect host plants in several ways, however, most studies measure only the amount of fruit and seed produced, and do not test seed viability. Therefore, the aim of this study was to assess the effects of the presence of ant-aphid interactions upon host plant productivity and seed viability in two different contexts: isolated and within an arthropod community. For this purpose we tested the hypothesis that in both isolated and community contexts, the presence of an ant-aphid interaction will have a positive effect on fruit and seed production, seed biomass and rate of seed germination, and a negative effect on abnormal seedling rates, in comparison to plants without ants. We performed a field mesocosm experiment containing five treatments: Ant-aphid, Aphid, Community, Ant-free community and Control. We counted fruits and seeds produced by each treatment, and conducted experiments for seed biomass and germinability. We found that in the community context the presence of an ant-aphid interaction negatively affected fruit and seed production. We think this may be because aphid attendance by tending-ants promotes aphid damage to the host plant, but without an affect on seed weight and viability. On the other hand, when isolated, the presence of an ant-aphid interaction positively affected fruit and seed production. These positive effects are related to the cleaning services offered to aphids by tending-ants, which prevent the development of saprophytic fungi on the surface of leaves, which would cause a decrease in photosynthetic rates. Our study is important because we evaluated some parameters of plant fitness that have not been addressed very well by other studies involving the effects of ant-aphid interactions mainly on plants with short life cycles. Lastly, our context dependent approach sheds new light on how ecological interactions can vary among different methods of crop management. PMID:28141849
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Directory of Open Access Journals (Sweden)
Ernesto Oliveira Canedo-Júnior
Full Text Available Ant-aphid interactions may affect host plants in several ways, however, most studies measure only the amount of fruit and seed produced, and do not test seed viability. Therefore, the aim of this study was to assess the effects of the presence of ant-aphid interactions upon host plant productivity and seed viability in two different contexts: isolated and within an arthropod community. For this purpose we tested the hypothesis that in both isolated and community contexts, the presence of an ant-aphid interaction will have a positive effect on fruit and seed production, seed biomass and rate of seed germination, and a negative effect on abnormal seedling rates, in comparison to plants without ants. We performed a field mesocosm experiment containing five treatments: Ant-aphid, Aphid, Community, Ant-free community and Control. We counted fruits and seeds produced by each treatment, and conducted experiments for seed biomass and germinability. We found that in the community context the presence of an ant-aphid interaction negatively affected fruit and seed production. We think this may be because aphid attendance by tending-ants promotes aphid damage to the host plant, but without an affect on seed weight and viability. On the other hand, when isolated, the presence of an ant-aphid interaction positively affected fruit and seed production. These positive effects are related to the cleaning services offered to aphids by tending-ants, which prevent the development of saprophytic fungi on the surface of leaves, which would cause a decrease in photosynthetic rates. Our study is important because we evaluated some parameters of plant fitness that have not been addressed very well by other studies involving the effects of ant-aphid interactions mainly on plants with short life cycles. Lastly, our context dependent approach sheds new light on how ecological interactions can vary among different methods of crop management.
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Lapin, D.
2013-01-01
Interactions of plants with pathogenic microorganisms are influenced by multiple biotic and abiotic factors. The host immune system can detect pathogens and restrict their growth and development, but also non-immunity related host factors and processes can contribute to pathogenesis by attracting
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The impact of plant chemical diversity on plant-herbivore interactions at the community level.
Salazar, Diego; Jaramillo, Alejandra; Marquis, Robert J
2016-08-01
Understanding the role of diversity in ecosystem processes and species interactions is a central goal of ecology. For plant-herbivore interactions, it has been hypothesized that when plant species diversity is reduced, loss of plant biomass to herbivores increases. Although long-standing, this hypothesis has received mixed support. Increasing plant chemical diversity with increasing plant taxonomic diversity is likely to be important for plant-herbivore interactions at the community level, but the role of chemical diversity is unexplored. Here we assess the effect of volatile chemical diversity on patterns of herbivore damage in naturally occurring patches of Piper (Piperaceae) shrubs in a Costa Rican lowland wet forest. Volatile chemical diversity negatively affected total, specialist, and generalist herbivore damage. Furthermore, there were differences between the effects of high-volatility and low-volatility chemical diversity on herbivore damage. High-volatility diversity reduced specialist herbivory, while low-volatility diversity reduced generalist herbivory. Our data suggest that, although increased plant diversity is expected to reduce average herbivore damage, this pattern is likely mediated by the diversity of defensive compounds and general classes of anti-herbivore traits, as well as the degree of specialization of the herbivores attacking those plants.
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TERMITES ENDANGERED TRADITIONAL MEDICAL PLANTS
Directory of Open Access Journals (Sweden)
Syaukani Syaukani
2014-04-01
Full Text Available Surveys on traditional medical plants affected by termites have been conducted since June to August 2010 at Ketambe, northern Aceh. Traditional medical plants and their natural habitats were obtained through interviewing local people. Termites were collected by adopted a Standardized Sampling Protocol and final. taxonomic confirmation was done with the help of Termite Research Group (the Natural History Museum, London. About 20 species of medical plants were attacked by termites with various levels. Nine genera and 20 species were collected from various habitats throughout Ketambe, Simpur as well as Gunung Setan villages. Coffe (Coffea arabica, hazelnut (Aleurites moluccana , and areca (Area catechu were among the worse of traditional medical plant that had been attached by the termites.
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Huanglongbing (HLB)-affected citrus often display zinc deficiency symptoms. In this study, supplemental zinc was applied to citrus to determine its effect on Candidatus Liberibacter asiaticus (Las) titer, HLB symptoms, and leaf microbiome. HLB-affected citrus were treated with various amounts of zi...
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Plant foods and plant-based diets: protective against childhood obesity?
Newby, P K
2009-05-01
The objective of this article is to review the epidemiologic literature examining the role of plant foods and plant-based diets in the prevention of childhood obesity. Available data suggest a protective effect of ready-to-eat cereal on risk of obesity, although prospective studies are still needed. Studies on fruit and vegetables; grains other than cereal; high-protein foods, including beans, legumes, and soy; fiber; and plant-based dietary patterns are inconsistent or generally null. The evidence base is limited, and most studies are fraught with methodologic limitations, including cross-sectional design, inadequate adjustment for potential confounders, and lack of consideration of reporting errors, stage of growth, and genetic influences. Well-designed prospective studies are needed. The lack of evidence showing an association between plant-based diets and childhood obesity does not mean that such diets should not be encouraged. Plant foods are highlighted in the Dietary Guidelines for Americans, and children do not meet the current recommendations for most plant foods. Although the advice to consume a plant-based, low-energy-dense diet is sound, ethical questions arise concerning the relatively high price of these diets in the United States and the way in which such diets are perceived in other parts of the world. Reducing the burden of childhood obesity, eliminating health disparities, and preventing the further spread of the disease around the globe will require not only policy interventions to ensure that plant foods are affordable and accessible to children of all income levels but also awareness of sociocultural norms that affect consumption.
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Directory of Open Access Journals (Sweden)
Watoo Phrompittayarat
2011-04-01
Full Text Available Brahmi or Bacopa monnieri (L. Wettst. is becoming popular as a food supplement due to its enhancing effect onmemory and intellect. Previous studies showed that a group of saponins are active compounds in this plant. However, untilnow little evidence has been obtained to indicate whether saponins are consistently present throughout the plant growthstages or the compounds are affected by the seasons. In order to answer those questions, we cultivated Brahmi under thenet house in three seasons. Influence of plant growth stages on saponin quantity and distribution was also investigated.In each season, treatments were plant ages with different plant parts having a factorial completely randomized design with 3replications. Five saponins, i.e. bacoside A3, bacopaside II, bacopaside X, bacopasaponin C and bacopaside I, were analyzedusing HPLC and reported as total saponins.The results showed that total saponin contents in Brahmi were the highest in rainy season while the weight yield ofBrahmi was the highest in summer. Ages of Brahmi (1-4 months slightly affected total saponin content. High level of totalsaponins (1.91±0.48% w/w was detected at the shoot of Brahmi. These findings indicate that the saponin quantity is affectedby seasons and the distribution of the saponins is different in each part of the plant. This information will be beneficial tothe production of Brahmi for both household and industry
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Bibliographical review of radioactive cesium uptake capacity and processes in aquatic plants
International Nuclear Information System (INIS)
Pally, Monique; Foulquier, Luc.
1981-11-01
Both freshwater and marine plants are included in this survey covering 217 reports published between 1954 and 1979. These articles involve the radiocesium abundance found in areas either directly or indirectly affected by liquid waste releases. They specify the concentration factors determined from field measurements and laboratory works. Other areas covered include contamination kinetics, radiocesium distribution in higher plants, effects of biological and environmental factors. Radiocesium uptake potential is higher in freshwater algae and plants than in marine algae. Radiocesium adsorption phenomena seem to predominate in algae over absorption, while in the higher freshwater plants absorption is the primary phenomena. In areas not directly affected by liquid wastes, plant activity levels increased until they reached 10000 pCi/kg wet weight in 1965, and reduced thereafter. In areas directly affected by waste discharges, the activity levels range from 10 to 16000 pCi/kg wet weight in seawater, and from practically zero to 230000 pCi/kg in fresh water. This variability also affects the concentration factors. In most cases, the values measured in marine algae range from 10 to 100; the highest radiocesium uptake is found in brown algae and red algae. The concentration factors measured in freshwater mosses and algae are most often around 4000, while they are about 2000 in submerged, floating and emergent plants. Some plants, specially mosses and algae, proved to be better bioindicators than others. The biological half-lives range from 2 to 21 days in marine algae, and from 1 to 65 days in freshwater plants. This survey underscores the necessity of allowing for the ecological characteristics of each site when evaluating the impact of nuclear plants [fr
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Moreno, José M.; Parra, Antonio; Dannenmann, Michael; Ramírez, David A.; Diaz-Pines, Eugenio; Tejedor, Javier; Kitzler, Barbara; Karhu, Kristina; Resco, Victor; Povoas, Luciano
2010-05-01
Predicted changes in the seasonality and amount of rainfall under a changing climate have the potential to dramatically alter ecosystem function and species composition. Moreover, in fire-prone ecosystems, the joint effects of fire and increasing aridity may create irreversible changes to the services these ecosystems provide. To understand the effects of increasing drought and fire in a Mediterranean shrubland, we implemented an automated rainfall manipulation system, with rain-out shelters which automatically fold and unfold when conditions are rainy and dry, respectively. In January 2009, we implemented five different treatments, where annual precipitation was reduced by diminishing summer rainfall from the long-term historical average, up to a 40% reduction, following IPCC scenarios. In September 2009, we uninstalled all the shelters to burn the different plots, and reinstalled the shelters immediately afterwards. In this talk, we will present the preliminary results of an integrated experiment which aims at understanding the concomitant effects of fire and different drought intensities on the species composition and greenhouse gas balance (CO2, N2O and CH4) of a Mediterranean shrubland. We observed that plant growth was more severely affected by drought in the more shallow-rooted, malacophyllous shrub (from 116 to -7.2 mg/g/d in Cistus ladanifer), than in a deeper-rooted heather (from 5.5 to 66.9 mg/g/day in Erica arborea). This growth response was mediated by species-specific differences in hydraulics, leaf morphology and photosynthetic gas exchange of each species. Analyses of changes in species composition after fire are currently undergoing. The precipitation reduction treatments exerted drought stress on CH4 oxidizing microorganisms and thus reduced the CH4 sink strength of the ecosystem during the pre-fire period. Furthermore, the net CH4 uptake at the soil-atmosphere interface was reduced by the fire for a period of at least one month. Pedosphere
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DEFF Research Database (Denmark)
Foster, Randy; Mattsson, Ole; Mundy, John
2003-01-01
Recent work on the fragile fiber mutants of Arabidopsis has identified microtubule-associated proteins that affect the orientation of cellulose microfibrils in cell walls, a major determinant of plant elongation growth. These same proteins are implicated in responses to gibberellin, provoking fresh...
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Training of nuclear power plant personnel in Canada
International Nuclear Information System (INIS)
Tennant, D.
1993-01-01
All of the utilities, Ontario Hydro, Hydro Quebec and New Brunswick Power, operating Nuclear Power Plants in Canada have Training Centres which provide training for all of their plant personnel whose job activities could affect plant and personnel safety. This report points out the methods used for training, which generally conform to that described by the IAEA as a Systematic Approach to Training (SAT)
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Plant arginyltransferases (ATEs
Directory of Open Access Journals (Sweden)
Tatiana Domitrovic
Full Text Available Abstract Regulation of protein stability and/or degradation of misfolded and damaged proteins are essential cellular processes. A part of this regulation is mediated by the so-called N-end rule proteolytic pathway, which, in concert with the ubiquitin proteasome system (UPS, drives protein degradation depending on the N-terminal amino acid sequence. One important enzyme involved in this process is arginyl-t-RNA transferase, known as ATE. This enzyme acts post-translationally by introducing an arginine residue at the N-terminus of specific protein targets to signal degradation via the UPS. However, the function of ATEs has only recently begun to be revealed. Nonetheless, the few studies to date investigating ATE activity in plants points to the great importance of the ATE/N-end rule pathway in regulating plant signaling. Plant development, seed germination, leaf morphology and responses to gas signaling in plants are among the processes affected by the ATE/N-end rule pathway. In this review, we present some of the known biological functions of plant ATE proteins, highlighting the need for more in-depth studies on this intriguing pathway.
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Water-Related Power Plant Curtailments: An Overview of Incidents and Contributing Factors
Energy Technology Data Exchange (ETDEWEB)
McCall, James [National Renewable Energy Lab. (NREL), Golden, CO (United States); Macknick, Jordan [National Renewable Energy Lab. (NREL), Golden, CO (United States); Macknick, Jordan [National Renewable Energy Lab. (NREL), Golden, CO (United States)
2016-12-01
Water temperatures and water availability can affect the reliable operations of power plants in the United States. Data on water-related impacts on the energy sector are not consolidated and are reported by multiple agencies. This study provides an overview of historical incidents where water resources have affected power plant operations, discusses the various data sources providing information, and creates a publicly available and open access database that contains consolidated information about water-related power plant curtailment and shut-down incidents. Power plants can be affected by water resources if incoming water temperatures are too high, water discharge temperatures are too high, or if there is not enough water available to operate. Changes in climate have the potential to exacerbate uncertainty over water resource availability and temperature. Power plant impacts from water resources include curtailment of generation, plant shut-downs, and requests for regulatory variances. In addition, many power plants have developed adaptation approaches to reducing the potential risks of water-related issues by investing in new technologies or developing and implementing plans to undertake during droughts or heatwaves. This study identifies 42 incidents of water-related power plant issues from 2000-2015, drawing from a variety of different datasets. These incidents occur throughout the U.S., and affect coal and nuclear plants that use once-through, recirculating, and pond cooling systems. In addition, water temperature violations reported to the Environmental Protection Agency are also considered, with 35 temperature violations noted from 2012-2015. In addition to providing some background information on incidents, this effort has also created an open access database on the Open Energy Information platform that contains information about water-related power plant issues that can be updated by users.
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Nitric oxide and plant iron homeostasis.
Buet, Agustina; Simontacchi, Marcela
2015-03-01
Like all living organisms, plants demand iron (Fe) for important biochemical and metabolic processes. Internal imbalances, as a consequence of insufficient or excess Fe in the environment, lead to growth restriction and affect crop yield. Knowledge of signals and factors affecting each step in Fe uptake from the soil and distribution (long-distance transport, remobilization from old to young leaves, and storage in seeds) is necessary to improve our understanding of plant mineral nutrition. In this context, the role of nitric oxide (NO) is discussed as a key player in maintaining Fe homeostasis through its cross talk with hormones, ferritin, and frataxin and the ability to form nitrosyl-iron complexes. © 2015 New York Academy of Sciences.
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Ion distribution and gas exchange of hydroponically grown sunflower plants as affected by salinity
Directory of Open Access Journals (Sweden)
Anna Rita Rivelli
2006-09-01
Full Text Available This paper reports the results of a trial carried out on sunflower plants (Helianthus annuus L., Romsun HS90 grown in the greenhouse using inert substrate and two automatic and closed hydroponic systems: one of them hosting the control (C with plants grown under optimal conditions on Hoagland nutrient solution, the other one, the salt treatment (S, with plants exposed to constant salt stress through adding 150 mM of NaCl to the nutrient solution. Salt supply caused a sharp reduction in leaf area development and dry matter production, especially in the first 4 weeks when leaves showed to be more sensitive than stem and roots. Such a reduction is attributable to the drop in net CO2 assimilation rate, transpiration and stomatal conductance and it was, on average, equal to 30, 26 and 40%, respectively, with respect to the control. The investigated genotype was not able to exclude Cl- and Na+ and considerable amounts accumulated in leaves, stem and roots. Concentration increased in leaves in the basipetal direction. Though sunflower has an efficient endogenous adaptation system by which it redistributes ions in the whole plant, with greater accumulation in older leaves, growth inhibition could be attributed to specific ion toxicity effects, and of chlorine in particular, on metabolic processes and thus on photosynthesis.
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Ion distribution and gas exchange of hydroponically grown sunflower plants as affected by salinity
Directory of Open Access Journals (Sweden)
Anna Rita Rivelli
Full Text Available This paper reports the results of a trial carried out on sunflower plants (Helianthus annuus L., Romsun HS90 grown in the greenhouse using inert substrate and two automatic and closed hydroponic systems: one of them hosting the control (C with plants grown under optimal conditions on Hoagland nutrient solution, the other one, the salt treatment (S, with plants exposed to constant salt stress through adding 150 mM of NaCl to the nutrient solution. Salt supply caused a sharp reduction in leaf area development and dry matter production, especially in the first 4 weeks when leaves showed to be more sensitive than stem and roots. Such a reduction is attributable to the drop in net CO2 assimilation rate, transpiration and stomatal conductance and it was, on average, equal to 30, 26 and 40%, respectively, with respect to the control. The investigated genotype was not able to exclude Cl- and Na+ and considerable amounts accumulated in leaves, stem and roots. Concentration increased in leaves in the basipetal direction. Though sunflower has an efficient endogenous adaptation system by which it redistributes ions in the whole plant, with greater accumulation in older leaves, growth inhibition could be attributed to specific ion toxicity effects, and of chlorine in particular, on metabolic processes and thus on photosynthesis.
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Recent advances in plant-herbivore interactions [version 1; referees: 2 approved
Directory of Open Access Journals (Sweden)
Deron E. Burkepile
2017-02-01
Full Text Available Plant-herbivore interactions shape community dynamics across marine, freshwater, and terrestrial habitats. From amphipods to elephants and from algae to trees, plant-herbivore relationships are the crucial link generating animal biomass (and human societies from mere sunlight. These interactions are, thus, pivotal to understanding the ecology and evolution of virtually any ecosystem. Here, we briefly highlight recent advances in four areas of plant-herbivore interactions: (1 plant defense theory, (2 herbivore diversity and ecosystem function, (3 predation risk aversion and herbivory, and (4 how a changing climate impacts plant-herbivore interactions. Recent advances in plant defense theory, for example, highlight how plant life history and defense traits affect and are affected by multiple drivers, including enemy pressure, resource availability, and the local plant neighborhood, resulting in trait-mediated feedback loops linking trophic interactions with ecosystem nutrient dynamics. Similarly, although the positive effect of consumer diversity on ecosystem function has long been recognized, recent advances using DNA barcoding to elucidate diet, and Global Positioning System/remote sensing to determine habitat selection and impact, have shown that herbivore communities are probably even more functionally diverse than currently realized. Moreover, although most diversity-function studies continue to emphasize plant diversity, herbivore diversity may have even stronger impacts on ecosystem multifunctionality. Recent studies also highlight the role of risk in plant-herbivore interactions, and risk-driven trophic cascades have emerged as landscape-scale patterns in a variety of ecosystems. Perhaps not surprisingly, many plant-herbivore interactions are currently being altered by climate change, which affects plant growth rates and resource allocation, expression of chemical defenses, plant phenology, and herbivore metabolism and behavior. Finally
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Williams, Wyatt I.; Friedman, Jonathan M.; Gaskin, John F.; Norton, Andrew P.
2014-01-01
Evolution has contributed to the successful invasion of exotic plant species in their introduced ranges, but how evolution affects particular control strategies is still under evaluation. For instance, classical biological control, a common strategy involving the utilization of highly specific natural enemies to control exotic pests, may be negatively affected by host hybridization because of shifts in plant traits, such as root allocation or chemical constituents. We investigated introgression between two parent species of the invasive shrub tamarisk (Tamarix spp.) in the western United States, and how differences in plant traits affect interactions with a biological control agent. Introgression varied strongly with latitude of origin and was highly correlated with plant performance. Increased levels of T. ramosissima introgression resulted in both higher investment in roots and tolerance to defoliation and less resistance to insect attack. Because tamarisk hybridization occurs predictably on the western U.S. landscape, managers may be able to exploit this information to maximize control efforts. Genetic differentiation in plant traits in this system underpins the importance of plant hybridization and may explain why some biological control releases are more successful than others.
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Organic and weed control in water supply reservoirs of power plants
International Nuclear Information System (INIS)
Eswaran, M.S.
2000-01-01
Aquatic weeds and algal control in water supply reservoirs used for multipurpose use need specific attention, since they pose a lot of problem for the operating plants by affecting (a) the water quality of boiler and feed waters, (b) the performance of DM plants by reducing the efficiency of Anion beds, (c) the performance of Activated Carbon Filters (ACF) and (d) fouling induced corrosion problems in cooling water systems (Heat Exchangers and Piping materials) causing plant outages leading to production losses. The photosynthetic activity of planktonic plants which are growing abundantly in the open reservoir, sustained by the relatively high inorganic phosphate levels shoots up the pH of the reservoir water to very high levels. High pH, Total Dissolved Solids (TDS) and depleted plants can increase corrosion problems affecting plant performance. This paper focuses on the type of weeds prominent in the water supply reservoir at Kalpakkam and the associated problems in the Nuclear Power Plants (NPPs). (author)
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Do Plants Eavesdrop on Floral Scent Signals?
Caruso, Christina M; Parachnowitsch, Amy L
2016-01-01
Plants emit a diverse array of volatile organic compounds that can function as cues to other plants. Plants can use volatiles emitted by neighbors to gain information about their environment, and respond by adjusting their phenotype. Less is known about whether the many different volatile signals that plants emit are all equally likely to function as cues to other plants. We review evidence for the function of floral volatile signals and conclude that plants are as likely to perceive and respond to floral volatiles as to other, better-studied volatiles. We propose that eavesdropping on floral volatile cues is particularly likely to be adaptive because plants can respond to these cues by adjusting traits that directly affect pollination and mating. Copyright © 2015 Elsevier Ltd. All rights reserved.
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Nodulation of leguminous plants as affected by root secretions and red light
Lie, T.A.
1964-01-01
Nodulation of bean plants, Phaseolus vulgaris L., in water culture was poor during hot sunny weather in the greenhouse. It did not improve when indoleacetic acid, kinetin, gibberellic acid, purines and pyrimidines, yeast and soil extract were added. Nodulation was enhanced by adding used
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Coleman-Derr, Devin; Desgarennes, Damaris; Fonseca-Garcia, Citlali; Gross, Stephen; Clingenpeel, Scott; Woyke, Tanja; North, Gretchen; Visel, Axel; Partida-Martinez, Laila P; Tringe, Susannah G
2016-01-01
Desert plants are hypothesized to survive the environmental stress inherent to these regions in part thanks to symbioses with microorganisms, and yet these microbial species, the communities they form, and the forces that influence them are poorly understood. Here we report the first comprehensive investigation of the microbial communities associated with species of Agave, which are native to semiarid and arid regions of Central and North America and are emerging as biofuel feedstocks. We examined prokaryotic and fungal communities in the rhizosphere, phyllosphere, leaf and root endosphere, as well as proximal and distal soil samples from cultivated and native agaves, through Illumina amplicon sequencing. Phylogenetic profiling revealed that the composition of prokaryotic communities was primarily determined by the plant compartment, whereas the composition of fungal communities was mainly influenced by the biogeography of the host species. Cultivated A. tequilana exhibited lower levels of prokaryotic diversity compared with native agaves, although no differences in microbial diversity were found in the endosphere. Agaves shared core prokaryotic and fungal taxa known to promote plant growth and confer tolerance to abiotic stress, which suggests common principles underpinning Agave-microbe interactions. No claim to US Government works. New Phytologist © 2015 New Phytologist Trust.
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Directory of Open Access Journals (Sweden)
Pu Wang
Full Text Available Spatial heterogeneity in light supply is common in nature. Many studies have examined the effects of heterogeneous light supply on growth, morphology, physiology and biomass allocation of clonal plants, but few have tested those effects on intraspecific competition. In a greenhouse experiment, we grew one (no competition or nine ramets (with intraspecific competition of a stoloniferous clonal plant, Duchesnea indica, in three homogeneous light conditions (high, medium and low light intensity and two heterogeneous ones differing in patch size (large and small patch treatments. The total light in the two heterogeneous treatments was the same as that in the homogeneous medium light treatment. Both decreasing light intensity and intraspecific competition significantly decreased the growth (biomass, number of ramets and total stolon length of D. indica. As compared with the homogeneous medium light treatment, the large patch treatment significantly increased the growth of D. indica without intraspecific competition. However, the growth of D. indica with competition did not differ among the homogeneous medium light, the large and the small patch treatments. Consequently, light heterogeneity significantly increased intraspecific competition intensity, as measured by the decreased log response ratio. These results suggest that spatial heterogeneity in light supply can alter intraspecific interactions of clonal plants.
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Antimalarial Activity of Plant Metabolites.
Pan, Wen-Hui; Xu, Xin-Ya; Shi, Ni; Tsang, Siu Wai; Zhang, Hong-Jie
2018-05-06
Malaria, as a major global health problem, continues to affect a large number of people each year, especially those in developing countries. Effective drug discovery is still one of the main efforts to control malaria. As natural products are still considered as a key source for discovery and development of therapeutic agents, we have evaluated more than 2000 plant extracts against Plasmodium falciparum . As a result, we discovered dozens of plant leads that displayed antimalarial activity. Our phytochemical study of some of these plant extracts led to the identification of several potent antimalarial compounds. The prior comprehensive review article entitled “Antimalarial activity of plant metabolites” by Schwikkard and Van Heerden (2002) reported structures of plant-derived compounds with antiplasmodial activity and covered literature up to the year 2000. As a continuation of this effort, the present review covers the antimalarial compounds isolated from plants, including marine plants, reported in the literature from 2001 to the end of 2017. During the span of the last 17 years, 175 antiplasmodial compounds were discovered from plants. These active compounds are organized in our review article according to their plant families. In addition, we also include ethnobotanical information of the antimalarial plants discussed.
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Antimalarial Activity of Plant Metabolites
Directory of Open Access Journals (Sweden)
Wen-Hui Pan
2018-05-01
Full Text Available Malaria, as a major global health problem, continues to affect a large number of people each year, especially those in developing countries. Effective drug discovery is still one of the main efforts to control malaria. As natural products are still considered as a key source for discovery and development of therapeutic agents, we have evaluated more than 2000 plant extracts against Plasmodium falciparum. As a result, we discovered dozens of plant leads that displayed antimalarial activity. Our phytochemical study of some of these plant extracts led to the identification of several potent antimalarial compounds. The prior comprehensive review article entitled “Antimalarial activity of plant metabolites” by Schwikkard and Van Heerden (2002 reported structures of plant-derived compounds with antiplasmodial activity and covered literature up to the year 2000. As a continuation of this effort, the present review covers the antimalarial compounds isolated from plants, including marine plants, reported in the literature from 2001 to the end of 2017. During the span of the last 17 years, 175 antiplasmodial compounds were discovered from plants. These active compounds are organized in our review article according to their plant families. In addition, we also include ethnobotanical information of the antimalarial plants discussed.
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Schiavon, Michela; Pilon-Smits, Elizabeth A H
2017-03-01
Contents 1582 I. 1582 II. 1583 III. 1588 IV. 1590 V. 1592 1592 References 1592 SUMMARY: The importance of selenium (Se) for medicine, industry and the environment is increasingly apparent. Se is essential for many species, including humans, but toxic at elevated concentrations. Plant Se accumulation and volatilization may be applied in crop biofortification and phytoremediation. Topics covered here include beneficial and toxic effects of Se on plants, mechanisms of Se accumulation and tolerance in plants and algae, Se hyperaccumulation, and ecological and evolutionary aspects of these processes. Plant species differ in the concentration and forms of Se accumulated, Se partitioning at the whole-plant and tissue levels, and the capacity to distinguish Se from sulfur. Mechanisms of Se hyperaccumulation and its adaptive significance appear to involve constitutive up-regulation of sulfate/selenate uptake and assimilation, associated with elevated concentrations of defense-related hormones. Hyperaccumulation has evolved independently in at least three plant families, probably as an elemental defense mechanism and perhaps mediating elemental allelopathy. Elevated plant Se protects plants from generalist herbivores and pathogens, but also gives rise to the evolution of Se-resistant specialists. Plant Se accumulation affects ecological interactions with herbivores, pollinators, neighboring plants, and microbes. Hyperaccumulation tends to negatively affect Se-sensitive ecological partners while facilitating Se-resistant partners, potentially affecting species composition and Se cycling in seleniferous ecosystems. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.
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Insect herbivores should follow plants escaping their relatives
Yguel, B.; Bailey, R.I.; Villemant, C.; Brault, A.; Jactel, H.; Prinzing, A.
2014-01-01
Neighboring plants within a local community may be separated by many millions of years of evolutionary history, potentially reducing enemy pressure by insect herbivores. However, it is not known how the evolutionary isolation of a plant affects the fitness of an insect herbivore living on such a
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DEFF Research Database (Denmark)
Hansen, Veronika; Hauggaard-Nielsen, Henrik; Petersen, Carsten Tilbæk
2016-01-01
Abstract Gasification biochar (GB) contains recalcitrant carbon that can contribute to soil carbon sequestration and soil quality improvement. However, the impact of GB on plant-available water capacity (AWC) and plant growth in diverse soil types still needs to be explored. A pot experiment......, the reduced water regime significantly affected plant growth and water consumption, whereas the effect was less pronounced in the coarse sand. Irrespective of the soil type, both GBs increased AWC by 17–42%, with the highest absolute effect in the coarse sand. The addition of SGB to coarse sand led...
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Zhang, Qian; Yang, Ruyi; Tang, Jianjun; Yang, Haishui; Hu, Shuijin; Chen, Xin
2010-08-24
Negative or positive feedback between arbuscular mycorrhizal fungi (AMF) and host plants can contribute to plant species interactions, but how this feedback affects plant invasion or resistance to invasion is not well known. Here we tested how alterations in AMF community induced by an invasive plant species generate feedback to the invasive plant itself and affect subsequent interactions between the invasive species and its native neighbors. We first examined the effects of the invasive forb Solidago canadensis L. on AMF communities comprising five different AMF species. We then examined the effects of the altered AMF community on mutualisms formed with the native legume forb species Kummerowia striata (Thunb.) Schindl. and on the interaction between the invasive and native plants. The host preferences of the five AMF were also assessed to test whether the AMF form preferred mutualistic relations with the invasive and/or the native species. We found that S. canadensis altered AMF spore composition by increasing one AMF species (Glomus geosporum) while reducing Glomus mosseae, which is the dominant species in the field. The host preference test showed that S. canadensis had promoted the abundance of AMF species (G. geosporum) that most promoted its own growth. As a consequence, the altered AMF community enhanced the competitiveness of invasive S. canadensis at the expense of K. striata. Our results demonstrate that the invasive S. canadensis alters soil AMF community composition because of fungal-host preference. This change in the composition of the AMF community generates positive feedback to the invasive S. canadensis itself and decreases AM associations with native K. striata, thereby making the native K. striata less dominant.
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Directory of Open Access Journals (Sweden)
Qian Zhang
2010-08-01
Full Text Available Negative or positive feedback between arbuscular mycorrhizal fungi (AMF and host plants can contribute to plant species interactions, but how this feedback affects plant invasion or resistance to invasion is not well known. Here we tested how alterations in AMF community induced by an invasive plant species generate feedback to the invasive plant itself and affect subsequent interactions between the invasive species and its native neighbors. We first examined the effects of the invasive forb Solidago canadensis L. on AMF communities comprising five different AMF species. We then examined the effects of the altered AMF community on mutualisms formed with the native legume forb species Kummerowia striata (Thunb. Schindl. and on the interaction between the invasive and native plants. The host preferences of the five AMF were also assessed to test whether the AMF form preferred mutualistic relations with the invasive and/or the native species. We found that S. canadensis altered AMF spore composition by increasing one AMF species (Glomus geosporum while reducing Glomus mosseae, which is the dominant species in the field. The host preference test showed that S. canadensis had promoted the abundance of AMF species (G. geosporum that most promoted its own growth. As a consequence, the altered AMF community enhanced the competitiveness of invasive S. canadensis at the expense of K. striata. Our results demonstrate that the invasive S. canadensis alters soil AMF community composition because of fungal-host preference. This change in the composition of the AMF community generates positive feedback to the invasive S. canadensis itself and decreases AM associations with native K. striata, thereby making the native K. striata less dominant.
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Aroma of some plants cultivated in Lithuania : composition, processing and release
Bylaite, E.
2000-01-01
In this study, some factors affecting the aroma of some plants of the families Umbelliferae and Asteraceae were evaluated. The composition of the aromas is influenced by several factors: plant family, harvesting time, anatomical part of plant,
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Bernstein, Nirit; Sela Saldinger, Shlomo; Dudai, Nativ; Gorbatsevich, Elena
2017-01-01
Crop produce can be contaminated in the field during cultivation by bacterial human pathogens originating from contaminated soil or irrigation water. The bacterial pathogens interact with the plant, can penetrate the plant via the root system and translocate and survive in above-ground tissues. The present study is first to investigate effects of an abiotic stress, salinity, on the interaction of plants with a bacterial human pathogen. The main sources of human bacterial contamination of plants are manures and marginal irrigation waters such as treated or un-treated wastewater. These are often saline and induce morphological, chemical and physiological changes in plants that might affect the interaction between the pathogens and the plant and thereby the potential for plant contamination. This research studied effects of salinity on the internalization of the bacterial human pathogen Salmonella enterica serovar Newport via the root system of sweet-basil plants, dissemination of the bacteria in the plant, and kinetics of survival in planta . Irrigation with 30 mM NaCl-salinity induced typical salt-stress effects on the plant: growth was reduced, Na and Cl concentrations increased, K and Ca concentrations reduced, osmotic potential and anti-oxidative activity were increased by 30%, stomatal conductance was reduced, and concentrations of essential-oils in the plants increased by 26%. Despite these physical, chemical and morphological changes in the plants, root internalization of the bacteria and its translocation to the shoot were not affected, and neither was the die-off rate of Salmonella in planta . The results demonstrate that the salinity-induced changes in the sweet-basil plants did not affect the interaction between Salmonella and the plant and thereby the potential for crop contamination.
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Biological significance of complex N-glycans in plants and their impact on plant physiology.
Strasser, Richard
2014-01-01
Asparagine (N)-linked protein glycosylation is a ubiquitous co- and post-translational modification which can alter the biological function of proteins and consequently affects the development, growth, and physiology of organisms. Despite an increasing knowledge of N-glycan biosynthesis and processing, we still understand very little about the biological function of individual N-glycan structures in plants. In particular, the N-glycan-processing steps mediated by Golgi-resident enzymes create a structurally diverse set of protein-linked carbohydrate structures. Some of these complex N-glycan modifications like the presence of β1,2-xylose, core α1,3-fucose or the Lewis a-epitope are characteristic for plants and are evolutionary highly conserved. In mammals, complex N-glycans are involved in different cellular processes including molecular recognition and signaling events. In contrast, the complex N-glycan function is still largely unknown in plants. Here, in this short review, I focus on important recent developments and discuss their implications for future research in plant glycobiology and plant biotechnology.
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Relationship of sulfur content of soils and plants
Energy Technology Data Exchange (ETDEWEB)
Hengl, F; Reckendorfer, P
1928-01-01
Crops were fertilized with fertilizers which contained chloride and sulfate in order to examine how the sulfur content of a plant may be affected by that of the soil. At the time of flowering the respective chlorine or sulfate content of the plants was considerably above that of the controls; differences were less, however, when the plants were fully mature. Sulfate, in particular, was little different. In field observations, little correlation was noted between sulfate content of plants and soils. Natural variations in the sulfur content of plants were greater than the increases attributable to smoke air pollution. 2 tables.
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Polonium-210 and lead-210 contamination of plants
Energy Technology Data Exchange (ETDEWEB)
Popova, O N; Taskaev, A I
1977-01-01
A model experiment with a water culture of barley grown in closed vessels, with an increased content of radon-222 in the air, has demonstrated an intensive contamination of the overground part and roots of the plant with polonium-210 and lead-210. Roots having no overground part were affected by radionuclides in a similar way as those of intact plants. Contamination was minimal in the plants grown from soil cultures.
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Analysis and utilization of plant antioxidative mechanism by radiation
Energy Technology Data Exchange (ETDEWEB)
Lee, Haeng Soon; Kwak, Sang Soo; Kwon, Hye Gyung [Korea Research Institute of Bioscience and Biotechnology, Taejon (Korea)
1999-03-01
The gamma radiation-induced changes of antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) in callus cultures of cassava (Manihot esculenta) and sweet potato (Ipomoea batatas) were investigated. Both cell lines irradiated with 50 and 70 Gy on 7 days after subculture inhibited significantly the cell growth by 50% and 80% at 14 days after treatment (DAT), respectively. In 70 Gy irradiated with cassava calli SOD and POD specific activities increased by 4 and 2.5 folds at 14 DAT, respectively, whereas CAT activity was not affected. When sweet potato calli were irradiated 10 Gy POD activity showed the highest at 14 DAT, whereas the CAT activity was not affected. In the transgenic tobacco plants that overexpress swpal encoding anionic POD cDNA or swpnl encoding neutral POD cDNA, POD and SOD activities were not significantly increased after {gamma}-radiation treatment, but swpal-plants showed a higher activity than that of swpnl-or non-transgenic plants. Plant growth was severely inhibited showing a well correlation with the dose of radiation. Specially, {gamma}-radiation affected growth of shoot apical meristem. (author). 32 refs., 7 figs.
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Plant Respiration and Climate Change Effects
International Nuclear Information System (INIS)
Bruhn, D.
2002-04-01
Plant respiration is one of the key processes in terms of an understanding of plant growth and functioning in a future climate. Short- and long-term effects of temperature and CO 2 on plant respiration were investigated in a number of plant species. The experiments tested effects of either temperature and/or CO 2 from the level of individual respiratory enzymes, isolated mitochondria, whole-tissue, and up to the whole canopy level. The short-term effects of elevated atmospheric CO 2 on plant respiration appeared to be less than suggested so far in the literature. This was true both at the tissue level and for intact mitochondria. Respiratory enzymes can, however, be affected already at low CO 2 . These effects did not manifest itself at the tissue level, though, due to low degrees of control on the whole respiratory process exerted by the particular enzymes. Plant respiration on the other hand was affected by long-term growth at elevated atmospheric CO 2 . The findings of the reduced plant respiration at the leaf level were consistent with the literature and potential causes are discussed. Short-term effects of temperature on plant respiration were demonstrated to be dependent on the actual measurement temperature. Further, it is shown that mitochondrial leaf respiration in darkness and light differ substantially in the temperature sensitivity with the former being the far most sensitive. This has implications for modelling CO 2 exchange between vegetation and atmosphere as demonstrated here, since this has so far been neglected. Long-term effects of temperature resulted in respiratory acclimation in a number of species. Respiratory acclimation appeared not to occur to any one single type of growth temperature. The implications of this finding in combination with the timing of acclimation are discussed for modelling respiratory CO 2 release. (au)
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Plant Respiration and Climate Change Effects
Energy Technology Data Exchange (ETDEWEB)
Bruhn, D
2002-04-01
Plant respiration is one of the key processes in terms of an understanding of plant growth and functioning in a future climate. Short- and long-term effects of temperature and CO{sub 2} on plant respiration were investigated in a number of plant species. The experiments tested effects of either temperature and/or CO{sub 2} from the level of individual respiratory enzymes, isolated mitochondria, whole-tissue, and up to the whole canopy level. The short-term effects of elevated atmospheric CO{sub 2} on plant respiration appeared to be less than suggested so far in the literature. This was true both at the tissue level and for intact mitochondria. Respiratory enzymes can, however, be affected already at low CO{sub 2}. These effects did not manifest itself at the tissue level, though, due to low degrees of control on the whole respiratory process exerted by the particular enzymes. Plant respiration on the other hand was affected by long-term growth at elevated atmospheric CO{sub 2}. The findings of the reduced plant respiration at the leaf level were consistent with the literature and potential causes are discussed. Short-term effects of temperature on plant respiration were demonstrated to be dependent on the actual measurement temperature. Further, it is shown that mitochondrial leaf respiration in darkness and light differ substantially in the temperature sensitivity with the former being the far most sensitive. This has implications for modelling CO{sub 2} exchange between vegetation and atmosphere as demonstrated here, since this has so far been neglected. Long-term effects of temperature resulted in respiratory acclimation in a number of species. Respiratory acclimation appeared not to occur to any one single type of growth temperature. The implications of this finding in combination with the timing of acclimation are discussed for modelling respiratory CO{sub 2} release. (au)
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Plant community responses to climate change
Energy Technology Data Exchange (ETDEWEB)
Kongstad, J.
2012-07-01
Climate change is expected to affect terrestrial ecosystems across the globe with increased atmospheric CO{sub 2} concentration, higher temperatures and changes in precipitation patterns. These environmental factors are drivers of many important ecosystem processes, and changes in ecosystem function are therefore expected in the future. The aim of this PhD-thesis was to examine the effects of climate change on aboveground plant growth, plant composition and plant phenology in Danish heathland ecosystems. Two sites were investigated in large-scale field experiments: 1) the CLIMAITE site, 'Brandbjerg' and 2) the INCREASE site at Mols. Field manipulations lasted years and included: Warming, summer drought and (CLIMAITE only) elevated CO{sub 2} concentrations. The treatments were applied individually and in all possible combinations. Further, at Brandbjerg, but outside the treatment plots, a study was performed on the effects nitrogen and phosphorus addition on phenology, chemistry and growth of the dominant grass Deschampsia flexuosa (Wavy Hairgrass). In general, the aboveground vegetation responded less than expected to changing climatic conditions; even though Calluna vulgaris (Heather) increased in biomass over the study period, the biomass was not affected by the manipulations, indicating that C. vulgaris, has a strong resistance to changes in climate. Also, the grass biomass (primarily D. flexuosa) was not affected and was relatively constant over the period. I argue that the resilience of D. flexuosa towards the climatic treatments came from the plants ability to let the tissue die back, and then quickly recover once conditions again became favourable. That gave the plant a high resilience to changes in climatic factors. Calluna vulgaris, on the other hand, showed a resistance to changes by constantly maintaining the growth during the whole season, probably because of its evergreen status. Together, the two different strategies made the heathland
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Patterns of woody plant species diversity in Lebanon as affected by climatic and soil properties
International Nuclear Information System (INIS)
Zahreddine, H.; Barker, D.; Struve, D.; Martin, F.; Quigley, M.; Sleem, K.
2007-01-01
Lebanese biodiversity is threatened by tourist and urban development, political instability, over-collection of medicinal and aromatic plants, lack of compliance to the regulations prohibiting over-exploitation from the wild, over-grazing and forest fires. A large number of the native species have unexplored economic potential for either medicinal or ornamental use. One way to preserve these species is by propagation and reintroduction into appropriate habitats. However, this requires an understanding of the species biology and environment. The relationship of nine species to the soil and climatic conditions in eight sites along an altitudinal gradient was studied. Individual species were counted and identified within transects at each site. Climatic data were collected and soil samples were taken and analyzed for soil texture, soil pH, EC, CaCO3, organic matter content and the following nutrients: Ca, Mn, Na, Fe, P, K, Cu, Mg, and Zn. Each ecosystem had a unique environment that could be described using the first two factors (70.3 % of variation) in a Factor Analysis of the six most important variables. Some species densities were affected by soil conditions (the first factor) while climatic conditions (the second factor) explained the densities of other species. Recommendations are made for the in-situ and ex-situ preservations of the nine species and their ecosystems.(author)
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Possible effects of regulating hydroponic water temperature on plant ...
African Journals Online (AJOL)
Water temperature can affect many physiological processes during plant growth and development. Temperatures below or above optimum levels may influence plant metabolic activities positively or negatively. This may include accumulation of different metabolites such as phenolic compounds, reactive oxygen species ...
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Mercury Concentrations in Plant Tissues as Affected by FGDG Application to Soil
Flue Gas Desulfurization Gypsum (FGDG) is produced by reducing sulfur dioxide emissions from themo-electric coal-fired power plants. The most common practice of FGDG production may trap some of the Mercury (Hg) present in the coal that normally would escape as vapor in the stack gases. Concern for t...
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2012-01-01
Background Induced defense responses to herbivores are generally believed to have evolved as cost-saving strategies that defer the fitness costs of defense metabolism until these defenses are needed. The fitness costs of jasmonate (JA)-mediated defenses have been well documented. Those of the early signaling units mediating induced resistance to herbivores have yet to be examined. Early signaling components that mediate herbivore-induced defense responses in Nicotiana attenuata, have been well characterized and here we examine their growth and fitness costs during competition with conspecifics. Two mitogen-activated protein kinases (MAPKs), salicylic acid (SA)-induced protein kinase (SIPK) and wound-induced protein kinase (WIPK) are rapidly activated after perception of herbivory and both kinases regulate herbivory-induced JA levels and JA-mediated defense metabolite accumulations. Since JA-induced defenses result in resource-based trade-offs that compromise plant productivity, we evaluated if silencing SIPK (irSIPK) and WIPK (irWIPK) benefits the growth and fitness of plants competiting with wild type (WT) plants, as has been shown for plants silenced in JA-signaling by the reduction of Lipoxygenase 3 (LOX3) levels. Results As expected, irWIPK and LOX3-silenced plants out-performed their competing WT plants. Surprisingly, irSIPK plants, which have the largest reductions in JA signaling, did not. Phytohormone profiling of leaves revealed that irSIPK plants accumulated higher levels of SA compared to WT. To test the hypothesis that these high levels of SA, and their presumed associated fitness costs of pathogen associated defenses in irSIPK plants had nullified the JA-deficiency-mediated growth benefits in these plants, we genetically reduced SA levels in irSIPK plants. Reducing SA levels partially recovered the biomass and fitness deficits of irSIPK plants. We also evaluated whether the increased fitness of plants with reduced SA or JA levels resulted from
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Caplan, Joshua S; Stone, Bram W G; Faillace, Cara A; Lafond, Jonathan J; Baumgarten, Joni M; Mozdzer, Thomas J; Dighton, John; Meiners, Scott J; Grabosky, Jason C; Ehrenfeld, Joan G
2017-04-01
Temperate deciduous forest understoreys are experiencing widespread changes in community composition, concurrent with increases in rates of nitrogen supply. These shifts in plant abundance may be driven by interspecific differences in nutrient foraging (i.e. conservative vs. acquisitive strategies) and, thus, adaptation to contemporary nutrient loading conditions. This study sought to determine if interspecific differences in nutrient foraging could help explain patterns of shrub success and decline in eastern North American forests. Using plants grown in a common garden, fine root traits associated with nutrient foraging were measured for six shrub species. Traits included the mean and skewness of the root diameter distribution, specific root length (SRL), C:N ratio, root tissue density, arbuscular mycorrhizal colonization and foraging precision. Above- and below-ground productivity were also determined for the same plants, and population growth rates were estimated using data from a long-term study of community dynamics. Root traits were compared among species and associations among root traits, measures of productivity and rates of population growth were evaluated. Species fell into groups having thick or thin root forms, which correspond to conservative vs. acquisitive nutrient foraging strategies. Interspecific variation in root morphology and tissue construction correlated with measures of productivity and rates of cover expansion. Of the four species with acquisitive traits, three were introduced species that have become invasive in recent decades, and the fourth was a weedy native. In contrast, the two species with conservative traits were historically dominant shrubs that have declined in abundance in eastern North American forests. In forest understoreys of eastern North America, elevated nutrient availability may impose a filter on species success in addition to above-ground processes such as herbivory and overstorey canopy conditions. Shrubs that have
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Shao-Yuan Leu; J.Y. Zhu
2013-01-01
Enzymatic saccharification of cellulose is a key step in conversion of plant biomass to advanced biofuel and chemicals. Many substrate-related factors affect saccharification. Rather than examining the role of each individual factor on overall saccharification efficiency, this study examined how each factor affects the three basic processes of a heterogeneous...
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Whole plant senescence of sunflower following seedhead removal
International Nuclear Information System (INIS)
Ho, InSun; Below, F.E.
1989-01-01
This study was undertaken to further clarify the relationship between seed development and monocarpic senescence of sunflower (Helianthus annuus L.). Field-grown plants with and without seedheads were evaluated for rate and duration of accumulation of dry weight, reduced N, and P by whole shoots, and for partitioning of these constituents within the individual plant parts. Concurrent with seedhead removal, [ 15 N]nitrate was applied to the plants in a selected are of the experimental plot. Whole plants (above ground portions) were harvested seven times during the seed-filling period and analyzed from dry weight, reduced N, and P. Although seedhead removal depressed the rates of dry weight, reduced N, and P accumulation by whole shoots, it extended the duration of accumulation of these constituents, relative to headed control plants. As a result, the final whole shoot dry weight and N and P contents at seed maturity were similar for deheaded and headed plants. Seedhead removal also affected the partitioning of dry matter, reduced N, and P but the relative proportions varied as a function of constituent and growth stage. Analysis of 15 N present in whole shoots at physiological maturity showed that similar amounts of nitrate were absorbed during the postflowering period by headed and deheaded plants. These data indicate that the absence of seeds does not affect the total accumulation of dry matter, reduced N, or P, by sunflower plants, but does alter the rates of accumulation and partitioning of these constituents
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International Nuclear Information System (INIS)
Bogdan, Katja; Schenk, Manfred K.
2009-01-01
Paddy rice may contribute considerably to the human intake of As. The knowledge of soil characteristics affecting the As content of the rice plant enables the development of agricultural measures for controlling As uptake. During field surveys in 2004 and 2006, plant samples from 68 fields (Italy, Po-area) revealed markedly differing As concentration in polished rice. The soil factors total As (aquaregia) , pH, grain size fractions, total C, plant available P (CAL) , poorly crystalline Fe (oxal.) and plant available Si (Na-acetate) content that potentially affect As content of rice were determined. A multiple linear regression analysis showed a significant positive influence of the total As (aquaregia) and plant available P (CAL) content and a negative influence of the poorly crystalline Fe (oxal.) content of the soil on the As content in polished rice and rice straw. Si concentration in rice straw varied widely and was negatively related to As content in straw and polished rice. - Field selection for total As, poorly crystalline Fe and plant available P in soil might contribute to control As content of paddy rice.
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Planting and care of fine hardwood seedlings: diseases in hardwood tree plantings
Paula M. Pijut
2006-01-01
Hardwood trees planted for timber production, wildlife habitat, riparian buffers, native woodland restoration, windbreaks, watershed protection, erosion control, and conservation are susceptible to damage or even death by various native and exotic fungal or bacterial diseases. Establishment, growth, and the quality of the trees produced can be affected by these disease...
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Directory of Open Access Journals (Sweden)
Hamdia, M. A
2010-09-01
Full Text Available Several environmental factors adversely affect plant growth and development and final yield performance of a crop. Drought, salinity, nutrient imbalances (including mineral toxicities and deficiencies and extremes of temperature are among the major environmental constraints to crop productivity worldwide. Development of crop plants with stress tolerance, however, requires, among others, knowledge of the physiological mechanisms and genetic controls of the contributing traits at different plant developmental stages. In the past 2 decades, biotechnology research has provided considerable insights into the mechanism of biotic stress tolerance in plants at the molecular level. Furthermore, different abiotic stress factors may provoke osmotic stress, oxidative stress and protein denaturation in plants, which lead to similar cellular adaptive responses such as accumulation of compatible solutes, induction of stress proteins, and acceleration of reactive oxygen species scavenging systems. Recently, the authores try to improve plant tolerance to salinity injury through either chemical treatments (plant hormones, minerals, amino acids, quaternary ammonium compounds, polyamines and vitamins or biofertilizers treatments (Asymbiotic nitrogen-fixing bacteria, symbiotic nitrogen-fixing bacteria and mycorrhiza or enhanced a process used naturally by plants to minimise the movement of Na+ to the shoot, using genetic modification to amplify the process, helping plants to do what they already do - but to do it much better."
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Gelling agents and culture vessels affect in vitro multiplication of banana plantlets.
Kaçar, Y A; Biçen, B; Varol, I; Mendi, Y Y; Serçe, S; Cetiner, S
2010-03-09
Agar is the most commonly used gelling agent in media for plant tissue culture. Because of the high price of tissue-culture-grade agar, attempts have been made to identify suitable alternatives. The type of culture vessel and lid also affects the gaseous composition inside the vessel as well as light penetration. In turn, the vessel affects growth parameters, such as shoot elongation, proliferation and fresh weight, as well as hyperhydric degradation processes. We examined the effects of different culture vessels, including commercial glass jars, magenta boxes, and disposable containers, as well as different gelling agents (agar-agar, Agargel, Phytagel, and plant agar) on the micropropagation of Dwarf Cavendish bananas in an effort to find a combination that yields large numbers of high-quality seedlings. The different culture vessels did not significantly affect seedling culture success. The medium significantly affected shoot weight. Phytagel resulted in the highest shoot weight (overall mean = 2.4 g), while agar, Agargel and plant agar resulted in 1.7, 2.2 and 2.2 g, respectively. Disposable container/Phytagel and Magenta/Agargel combinations yielded the highest shoot weights (2.9 and 3.0 g, respectively). Mean shoot length increased progressively with subculture (four subcultures were made). The highest mean shoot length was obtained with Phytagel and Agargel media (6.4 and 6.3 cm, respectively). Shoot number was significantly affected by medium only at subculture 4. Overall, the highest mean shoot length was obtained with the Magenta/Agargel combination (8.5 cm). Phytagel and plant agar gave higher mean shoot number than agar and Agargel (2.1, 2.1 and 1.7 and 1.9, respectively). The costs of the media and of the culture vessels need to be taken into account for final choice of the banana shoot culture system.
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Kurm, Viola; van der Putten, W.H.; Pineda, A.M.; Hol, W.H.G.
2018-01-01
• Background and Aims Plant growth-promoting rhizobacteria (PGPR) strains can influence plant–insect interactions. However, little is known about the effect of changes in the soil bacterial community in general and especially the loss of rare soil microbes on these interactions. Here, the influence
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International Nuclear Information System (INIS)
Garcia Rodriguez, A.; Schwee, S.M.
1994-01-01
The nuclear industry is currently faced with an intense pressure to reduce the cost of electric production. To achieve these cost reductions, utilities are changing the way they have traditionally operated. They are embracing innovative processes and systems to fundamentally change the way they have operated and maintained their plants. Plant monitoring and control technology has been instrumental in affecting these rapid and proactive changes. Our challenge is to use these new technologies in ways that improve plant reliability while lowering operation and maintenance costs. What must we do to increase operational time, improve safety and reliability while reducing all costs including fixed as well as labor? We will discuss an overall plant monitoring system vision that will allow these changes in operational practices. (Author)
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Does plant-Microbe interaction confer stress tolerance in plants: A review?
Kumar, Akhilesh; Verma, Jay Prakash
2018-03-01
The biotic and abiotic stresses are major constraints for crop yield, food quality and global food security. A number of parameters such as physiological, biochemical, molecular of plants are affected under stress condition. Since the use of inorganic fertilizers and pesticides in agriculture practices cause degradation of soil fertility and environmental pollutions. Hence it is necessary to develop safer and sustainable means for agriculture production. The application of plant growth promoting microbes (PGPM) and mycorrhizal fungi enhance plant growth, under such conditions. It offers an economically fascinating and ecologically sound ways for protecting plants against stress condition. PGPM may promote plant growth by regulating plant hormones, improve nutrition acquisition, siderophore production and enhance the antioxidant system. While acquired systemic resistance (ASR) and induced systemic resistance (ISR) effectively deal with biotic stress. Arbuscular mycorrhiza (AM) enhance the supply of nutrients and water during stress condition and increase tolerance to stress. This plant-microbe interaction is vital for sustainable agriculture and industrial purpose, because it depends on biological processes and replaces conventional agriculture practices. Therefore, microbes may play a key role as an ecological engineer to solve environmental stress problems. So, it is a feasible and potential technology in future to feed global population at available resources with reduced impact on environmental quality. In this review, we have attempted to explore about abiotic and biotic stress tolerant beneficial microorganisms and their modes of action to enhance the sustainable agricultural production. Copyright © 2017 Elsevier GmbH. All rights reserved.
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International Nuclear Information System (INIS)
Massas, I.; Skarlou, V.; Haidouti, C.; Giannakopoulou, F.
2010-01-01
Three rates of Ca(OH) 2 were applied to an acid soil and the 134 Cs uptake by radish, cucumber, soybean and sunflower plants was studied. The 134 Cs concentration in all plant species was reduced from 1.6-fold in the sunflower seeds to 6-fold in the soybean vegetative parts at the higher Ca(OH) 2 rate. Potassium (K) concentration in plants was also reduced, but less effectively. The significantly decreased 134 Cs-K soil to plant distribution factors (D.F.) clearly suggest a stronger effect of soil liming on 134 Cs than on K plant uptake. This observation was discussed in terms of ionic interactions in the soil matrix and within the plants. The results also indicated that the increased Ca 2+ concentration in the exchange phase and in the soil solution along with the improved root activity, due to the soil liming, enhanced the immobilization of 134 Cs in the soil matrix and consequently lowered the 134 Cs availability for plant uptake.
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Omnivore-herbivore interactions: thrips and whiteflies compete via the shared host plant.
Pappas, Maria L; Tavlaki, Georgia; Triantafyllou, Anneta; Broufas, George
2018-03-05
Phytophagy is a common feature among pure herbivorous insects and omnivores that utilise both plant and prey as food resources; nevertheless, experimental evidence for factors affecting their interactions is restricted to intraguild predation and predator-mediated competition. We herein focused on plant-mediated effects that could result from plant defence activation or quality alteration and compared the performance of an omnivore, the western flower thrips Frankliniella occidentalis, and a pure herbivore, the greenhouse whitefly Trialeurodes vaporariorum, on cucumber plants previously infested with either species. Furthermore, we recorded their behavioural responses when given a choice among infested and clean plants. Whiteflies laid less eggs on plants previously exposed to thrips but more on whitefly-infested plants. Thrips survival was negatively affected on whitefly-infested than on thrips-infested or clean plants. Notably, whiteflies developed significantly faster on plants infested with conspecifics. In accordance, whiteflies avoided thrips-infested plants and preferred whitefly-infested over clean plants. Thrips showed no preference for either infested or clean plants. Our study is a first report on the role of plant-mediated effects in shaping omnivore-herbivore interactions. Considering the factors driving such interactions we will likely better understand the ecology of the more complex relationships among plants and pest organisms.
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How does a change in the control room design affect diagnostic strategies in nuclear power plants?
International Nuclear Information System (INIS)
Kim, Dong Young; Kim, Jonghyun
2014-01-01
Recently, main control rooms have been considerably changed by modern computer techniques. Some of the features that distinguish digital control rooms from conventional, analog rooms in nuclear power plants include advanced alarm systems, graphic information display systems, computerized procedure systems, and soft control. These features can bring changes in operator tasks, changing the characteristics of tasks or creating new tasks for operators. It is especially expected that these features may bring out changes in the operator's diagnostic tasks and strategies in a digital control room as compared with an analog control room. This study investigates the differences in the operator's diagnostic tasks and strategies in analog and digital control rooms. This study also attempts to evaluate how new systems in a digital control room affect diagnostic strategies. Three different approaches, which are complementary, are used to identify diagnostic strategies in the digital control room and in the analog control room: (1) observation in the simulator, (2) interview with operators, and (3) a literature review. The results show that the digital control room introduces new diagnosis strategies compared with the analog control room while also changing the characteristics of the strategies, mostly by gaining more support from the computerized system. (author)
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Model of the long-term transfer of radionuclides in forests
Energy Technology Data Exchange (ETDEWEB)
Avila, Rodolfo [Facilia AB, Bromma (Sweden)
2006-05-15
This report describes a model of the long-term behaviour in temperate and boreal forests of radionuclides entering the ecosystem with subsurface water. The model can be applied for most radionuclides that are of relevance in safety assessment of repositories for high-level radioactive waste. The model can be used for estimating radionuclide concentrations in soil, trees, understorey plants, mushrooms and forest mammals. A recommended (nominal) value and an interval of variation are provided for each model parameter and a classification of parameters by the degree of confidence in the values is given. Model testing against existing empirical data showing satisfactory results is also presented. Forests can play an important role in the spatial and temporal distribution of radionuclides in the environment. Despite of this, forest ecosystems have not been addressed in previous safety assessments. This can be explained by the fact that a suitable model of the long-term transfer of a wide range of radionuclides in forests has not been readily available. The objective of this work was to develop a forest model applicable for a wide range of radionuclides of relevance for high level radioactive waste management (Am-241, Cl-36, Cs-135, I-129, Ni-59, Np-237, Pu-239, Ra-226, Sr-90, Tc-99, Th-232, U-238) that can potentially enter the ecosystem with contaminated groundwater. The model assumes that biomass growth, precipitation and evapo-transpiration drive the radionuclide cycling in the system by influencing the uptake of radionuclides by vegetation and their export from the system via runoff. The mathematical model of radionuclide transfer consists of a system of ordinary differential describing the mass balance in different forest compartments, taking into account the fluxes in and out from the compartment and the radionuclides decay. The fluxes between compartments are calculated by multiplying a transfer coefficient (TC) by the radionuclide inventory in the compartment
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Model of the long-term transfer of radionuclides in forests
International Nuclear Information System (INIS)
Avila, Rodolfo
2006-05-01
This report describes a model of the long-term behaviour in temperate and boreal forests of radionuclides entering the ecosystem with subsurface water. The model can be applied for most radionuclides that are of relevance in safety assessment of repositories for high-level radioactive waste. The model can be used for estimating radionuclide concentrations in soil, trees, understorey plants, mushrooms and forest mammals. A recommended (nominal) value and an interval of variation are provided for each model parameter and a classification of parameters by the degree of confidence in the values is given. Model testing against existing empirical data showing satisfactory results is also presented. Forests can play an important role in the spatial and temporal distribution of radionuclides in the environment. Despite of this, forest ecosystems have not been addressed in previous safety assessments. This can be explained by the fact that a suitable model of the long-term transfer of a wide range of radionuclides in forests has not been readily available. The objective of this work was to develop a forest model applicable for a wide range of radionuclides of relevance for high level radioactive waste management (Am-241, Cl-36, Cs-135, I-129, Ni-59, Np-237, Pu-239, Ra-226, Sr-90, Tc-99, Th-232, U-238) that can potentially enter the ecosystem with contaminated groundwater. The model assumes that biomass growth, precipitation and evapo-transpiration drive the radionuclide cycling in the system by influencing the uptake of radionuclides by vegetation and their export from the system via runoff. The mathematical model of radionuclide transfer consists of a system of ordinary differential describing the mass balance in different forest compartments, taking into account the fluxes in and out from the compartment and the radionuclides decay. The fluxes between compartments are calculated by multiplying a transfer coefficient (TC) by the radionuclide inventory in the compartment
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Fungal endophytes: modifiers of plant disease.
Busby, Posy E; Ridout, Mary; Newcombe, George
2016-04-01
Many recent studies have demonstrated that non-pathogenic fungi within plant microbiomes, i.e., endophytes ("endo" = within, "phyte" = plant), can significantly modify the expression of host plant disease. The rapid pace of advancement in endophyte ecology warrants a pause to synthesize our understanding of endophyte disease modification and to discuss future research directions. We reviewed recent literature on fungal endophyte disease modification, and here report on several emergent themes: (1) Fungal endophyte effects on plant disease span the full spectrum from pathogen antagonism to pathogen facilitation, with pathogen antagonism most commonly reported. (2) Agricultural plant pathosystems are the focus of research on endophyte disease modification. (3) A taxonomically diverse group of fungal endophytes can influence plant disease severity. And (4) Fungal endophyte effects on plant disease severity are context-dependent. Our review highlights the importance of fungal endophytes for plant disease across a broad range of plant pathosystems, yet simultaneously reveals that complexity within plant microbiomes presents a significant challenge to disentangling the biotic environmental factors affecting plant disease severity. Manipulative studies integrating eco-evolutionary approaches with emerging molecular tools will be poised to elucidate the functional importance of endophytes in natural plant pathosystems that are fundamental to biodiversity and conservation.
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Effects of Soil Quality Enhancement on Pollinator-Plant Interactions
Directory of Open Access Journals (Sweden)
Yasmin J. Cardoza
2012-01-01
Full Text Available Both biotic and abiotic factors can affect soil quality, which can significantly impact plant growth, productivity, and resistance to pests. However, the effects of soil quality on the interactions of plants with beneficial arthropods, such as pollinators, have not been extensively examined. We studied the effects of vermicompost (earthworm compost, VC soil amendment on behavioral and physiological responses of pollinators to flowers and floral resources, using cucumbers, Cucumis sativus, as our model system. Results from experiments conducted over three field seasons demonstrated that, in at least two out of three years, VC amendment significantly increased visit length, while reducing the time to first discovery. Bumblebee (Bombus impatiens workers that fed on flowers from VC-amended plants had significantly larger and more active ovaries, a measure of nutritional quality. Pollen fractions of flowers from VC-grown plants had higher protein compared to those of plants grown in chemically fertilized potting soil. Nectar sugar content also tended to be higher in flowers from VC-grown plants, but differences were not statistically significant. In conclusion, soil quality enhancement, as achieved with VC amendment in this study, can significantly affect plant-pollinator interactions and directly influences pollinator nutrition and overall performance.
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New handbook for standardised measurement of plant functional traits worldwide
Pérez-Harguindeguy N Díaz S Garnier E Lavorel S Poorter H Jaureguiberry P Bret-Harte MS Cor
2013-01-01
Plant functional traits are the features (morphological physiological phenological) that represent ecological strategies and determine how plants respond to environmental factors affect other trophic levels and influence ecosystem properties. Variation in plant functional traits and trait syndromes has proven useful for tackling many important ecological questions at a range of scales giving rise to a demand for standardised ways to measure ecologically meaningful plant traits. This line of r...
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Directory of Open Access Journals (Sweden)
A. Zarea Feizabadi
2016-07-01
in each plot in 2011. At the harvest time tuber yield and also percent and severity of infection was determined. All data was analyzed statistically and Duncan test was used for comparison of means. Results and Discussion: Analysis of variance results showed that, potato tuber yield was affected by the crop rotation, the rate of returning residues, and also interaction between rotation × returning residues statistically (P≤0.01.When 1000 tuber was considered, analysis of variance results showed, crop rotation had a very significant effect (P≤0.01 on number and percent of infected tubers to wireworm and its holes. The most infected tubers ie.42.34 and holed i.e. 61.4 and totally 4.24% of tubers were belonged to the rotation 2, where in the rapeseed crop was preceding plant. The least one was achieved in rotation 1, with the rates of 27, 37 and 2.8% where in potato crop was not planted previously. The most infection to wireworm was found in 100% residue returning to the soil with 3.8% and the least one in no residue returning to the soil, i.e. 3.4 %. Results showed with increasing residue returning to the soil, the damage of wireworms is increased too. Conclusion: Generally applying crop rotation using different crops and residue returning to the soil is resulted in higher potato tuber yield. This increasing rate for tuber yield was 116% and 57 % when the preceding crops were wheat and rapeseed respectively compared to the mean of rotations 3 and 4. For the aim of sustainable production of potato and reducing of wireworm damage it is necessary we focus on other crop rotation and the importance of C:N ratio and the rate of residue returning to the soil. So we need to conduct new experiments with these purposes.
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Bouckenooghe, Dave; Raja, Usman; Butt, Arif Nazir
2013-01-01
Capturing data from employee-supervisor dyads (N = 321) from eight organizations in Pakistan, including human service organizations, an electronics assembly plant, a packaging material manufacturing company, and a small food processing plant, we used moderated regression analysis to examine whether the relationships between trait affect (positive affectivity [PA] and negative affectivity [NA]) and two key work outcome variables (job performance and turnover) are contingent upon the level of job satisfaction. We applied the Trait Activation Theory to explain the moderating effect of job satisfaction on the relationship between affect and performance and between affect and turnover. Overall, the data supported our hypotheses. Positive and negative affectivity influenced performance and the intention to quit, and job satisfaction moderated these relationships. We discuss in detail the results of these findings and their implications for research and practice.
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Does the use of biofuels affect respiratory health among male Danish energy plant workers?
DEFF Research Database (Denmark)
Schlünssen, Vivi; Madsen, Anne Mette; Skov, Simon
2011-01-01
were collected by questionnaire. Spirometry, metacholine provocation tests and skin prick tests were performed on 310 workers. The work area concentrations of ‘total dust’ (n=181), airborne endotoxin (n=179), cultivable Aspergillus fumigatus (n=373) and cultivable fungi (n=406) were measured at each...... plant. Personal exposure was calculated from the time spent on different tasks and average work area exposures. Results Median (range) average personal exposures in biofuel plants were 0.05 (0 to 0.33) mg/m3 for ‘total’ dust and 3.5 (0 to 294) endotoxin units/m3 for endotoxin. Fungi were cultivated from...
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Vossen, T.; Towns, A.M.; Ruysschaert, S.; Quiroz Villarreal, D.K.; Andel, van T.
2014-01-01
Folk perceptions of health and illness include cultural bound syndromes (CBS), ailments generally confined to certain cultural groups or geographic regions and often treated with medicinal plants. Our aim was to compare definitions and plant use for CBS regarding child health in the context of the
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Fruiting of browse plants affected by pine site preparation in east Texas
John J. Stransky; Douglas Richardson
1977-01-01
Pine planting sites prepared by burning yielded 120 kg/ha of browse fruits the third growing season after site treatment. Control plots yielded 74, KG-bladed plots 57, and chopped plots 41 kg/ha. Blackberries, American beautyberry, sumac, Sebastian bush, muscadine grape, blueberries, and southern wax-myrtle were the principal species. Most fruit was available in summer...
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Atmospheric transformation of plant volatiles disrupts host plant finding
Li, Tao; Blande, James D.; Holopainen, Jarmo K.
2016-09-01
Plant-emitted volatile organic compounds (VOCs) play important roles in plant-insect interactions. Atmospheric pollutants such as ozone (O3) can react with VOCs and affect the dynamics and fidelity of these interactions. However, the effects of atmospheric degradation of plant VOCs on plant-insect interactions remains understudied. We used a system comprising Brassica oleracea subsp. capitata (cabbage) and the specialist herbivore Plutella xylostella to test whether O3-triggered VOC degradation disturbs larval host orientation, and to investigate the underlying mechanisms. Larvae oriented towards both constitutive and larva-induced cabbage VOC blends, the latter being the more attractive. Such behaviour was, however, dramatically reduced in O3-polluted environments. Mechanistically, O3 rapidly degraded VOCs with the magnitude of degradation increasing with O3 levels. Furthermore, we used Teflon filters to collect VOCs and their reaction products, which were used as odour sources in behavioural tests. Larvae avoided filters exposed to O3-transformed VOCs and spent less time searching on them compared to filters exposed to original VOCs, which suggests that some degradation products may have repellent properties. Our study clearly demonstrates that oxidizing pollutants in the atmosphere can interfere with insect host location, and highlights the need to address their broader impacts when evaluating the ecological significance of VOC-mediated interactions.
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Directory of Open Access Journals (Sweden)
Victoria L. SCAVEN, Nicole E. RAFFERTY
2013-06-01
Full Text Available Growing concern about the influence of climate change on flowering plants, pollinators, and the mutualistic interactions between them has led to a recent surge in research. Much of this research has addressed the consequences of warming for phenological and distributional shifts. In contrast, relatively little is known about the physiological responses of plants and insect pollinators to climate warming and, in particular, how these responses might affect plant-pollinator interactions. Here, we summarize the direct physiological effects of temperature on flowering plants and pollinating insects to highlight ways in which plant and pollinator responses could affect floral resources for pollinators, and pollination success for plants, respectively. We also consider the overall effects of these responses on plant-pollinator interaction networks. Plant responses to warming, which include altered flower, nectar, and pollen production, could modify floral resource availability and reproductive output of pollinating insects. Similarly, pollinator responses, such as altered foraging activity, body size, and life span, could affect patterns of pollen flow and pollination success of flowering plants. As a result, network structure could be altered as interactions are gained and lost, weakened and strengthened, even without the gain or loss of species or temporal overlap. Future research that addresses not only how plant and pollinator physiology are affected by warming but also how responses scale up to affect interactions and networks should allow us to better understand and predict the effects of climate change on this important ecosystem service [Current Zoology 59 (3: 418–426, 2013].
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Effect of different planting time on different varieties of strawberries
Zhong, Yue; Luo, Ya; Ge, Cong; Mo, Qin; Lin, Yajie; Luo, Shu; Tang, Haoru
2018-04-01
The experiment chose two strawberry varieties which planted in two periods of September 10 and September 20, in order to identify the optimum planting time of strawberries by exploring the effects of different planting time on strawberry quality and flowering initially. The results showed that different planting time will affect the growth and quality of strawberry, and the quality of September 10 planting strawberries is better than September 20 planting strawberries while there do exist some differences between strawberry varieties. In summary, the preliminary determination is that in Hanyuan area, the Hong Yan and Zhang Ji's optimum planting time is 10 September.
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Assessment of plant biomass and nitrogen nutrition with plant height in early-to mid-season corn.
Yin, Xinhua; Hayes, Robert M; McClure, M Angela; Savoy, Hubert J
2012-10-01
The physiological basis for using non-destructive high-resolution measurements of plant height through plant height sensing to guide variable-rate nitrogen (N) applications on corn (Zea mays L.) during early (six-leaf growth stage, V6) to mid (V12) season is largely unknown. This study was conducted to assess the relationships of plant biomass and leaf N with plant height in early- to mid-season corn under six different N rate treatments. Corn plant biomass was significantly and positively related to plant height under an exponential model when both were measured at V6. This relationship explained 62-78% of the variations in corn biomass production. Leaf N concentration was, in general, significantly and positively related to plant height when both were measured at V6, V8, V10 and V12. This relationship became stronger as the growing season progressed from V6 to V12. The relationship of leaf N with plant height in early- to mid-season corn was affected by initial soil N fertility and abnormal weather conditions. The relationship of leaf N concentration with plant height may provide a physiological basis for using plant height sensing to guide variable-rate N applications on corn. Copyright © 2012 Society of Chemical Industry.
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Radhakrishnan, Ramalingam; Baek, Kwang Hyun
2017-07-01
Climatic changes on earth affect the soil quality of agricultural lands, especially by increasing salt deposition in soil, which results in soil salinity. Soil salinity is a major challenge to growth and reproduction among glycophytes (including all crop plants). Soil bacteria present in the rhizosphere and/or roots naturally protect plants from the adverse effects of soil salinity by reprogramming the stress-induced physiological changes in plants. Bacteria can enrich the soil with major nutrients (nitrogen, phosphorus, and potassium) in a form easily available to plants and prevent the transport of excess sodium to roots (exopolysaccharides secreted by bacteria bind with sodium ions) for maintaining ionic balance and water potential in cells. Salinity also affects plant growth regulators and suppresses seed germination and root and shoot growth. Bacterial secretion of indole-3-acetic acid and gibberellins compensates for the salt-induced hormonal decrease in plants, and bacterial 1-aminocyclopropane-1-carboxylate (ACC) deaminase synthesis decreases ethylene production to stimulate plant growth. Furthermore, bacteria modulate the redox state of salinity-affected plants by enhancing antioxidants and polyamines, which leads to increased photosynthetic efficiency. Bacteria-induced accumulation of compatible solutes in stressed plants regulates plant cellular activities and prevents salt stress damage. Plant-bacterial interaction reprograms the expression of salt stress-responsive genes and proteins in salinity-affected plants, resulting in a precise stress mitigation metabolism as a defense mechanism. Soil bacteria increase the fertility of soil and regulate the plant functions to prevent the salinity effects in glycophytes. This review explains the current understanding about the physiological changes induced in glycophytes during bacterial interaction to alleviate the adverse effects of soil salinity stress. Copyright © 2017 Elsevier Masson SAS. All rights
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Preventive maintenance-A countermeasure to plant aging
International Nuclear Information System (INIS)
Hlubek, W.
1985-01-01
The aging of power plants is caused by manifold and different influences. For instance, mechanical and thermal stress, radiation exposure, denting or wastage can considerably affect the aging of plant components and thus cause premature failures of components. In this presentation, the term 'Plant Aging' in nuclear power plants is to be understood more comprehensively than wear on components and material fatigue. In addition, nuclear power plants are to be adjusted to the advancing state of the science and technology (state-of-the-art) in order to guarantee safe operation at all times. The preventive maintenance - as a countermeasure to plant aging - comprises the systematic checks and servicing of the plant systems in operation and follows aging by inspection and tests. Experience with Rheinisch-Westfaelisches Elektrizitaetswerk AG (RWE) preventive maintenance program at the Biblis NNP (1300 MW, PWR) is discussed. The concept of an 'Integrated Maintenance System' as a means to avoid 'Plant Aging' is presented
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Directory of Open Access Journals (Sweden)
Jonathon eMuller
2014-10-01
Full Text Available Buildings structures and surfaces are explicitly being used to grow plants, and these ‘urban plantings’ are typically designed for aesthetic value. Urban plantings also have the potential to contribute significant ‘ecological values’ by increasing urban habitat for animals such as arthropods and by increasing plant productivity. In this study, we evaluated how the provision of these additional ecological values is affected by plant species richness; the availability of essential resources for plants, such as water, light, space; and soil characteristics. We sampled 33 plantings located on the exterior of three buildings in the urban centre of Brisbane, Australia (subtropical climatic region over two, six week sampling periods characterised by different temperature and rainfall conditions. Plant cover was estimated as a surrogate for productivity as destructive sampling of biomass was not possible. We measured weekly light levels (photosynthetically active radiation, plant CO2 assimilation, soil CO2 efflux, and arthropod diversity.Differences in plant cover were best explained by a three-way interaction of plant species richness, management water regime and sampling period. As the richness of plant species increased in a planter, productivity and total arthropod richness also increased significantly - likely due to greater habitat heterogeneity and quality. Overall we found urban plantings can provide additional ecological values if essential resources are maintained within a planter such as water, light and soil temperature. Diverse urban plantings that are managed with these principles in mind can contribute to the attraction of diverse arthropod communities, and lead to increased plant productivity within a dense urban context.
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Wangensteen, Helle; Klarpås, Line; Alamgir, Mahiuddin; Samuelsen, Anne B. C.; Malterud, Karl E.
2013-01-01
Diarrhoea is a common disease which causes pain and may be deadly, especially in developing countries. In Bangladesh, diarrhoeal diseases affect thousands of people every year, and children are especially vulnerable. Bacterial toxins or viral infections are the most common cause of the disease. The diarrhoea outbreaks are often associated with flood affected areas with contaminated drinking water and an increased risk of spreading the water-borne disease. Not surprisingly, plants found in the near surroundings have been taken into use by the local community as medicine to treat diarrhoeal symptoms. These plants are cheaper and more easily available than conventional medicine. Our question is: What is the level of documentation supporting the use of these plants against diarrhoea and is their consumption safe? Do any of these plants have potential for further exploration? In this review, we have choosen seven plant species that are used in the treatment of diarrhoea; Diospyros peregrina, Heritiera littoralis, Ixora coccinea, Pongamia pinnata, Rhizophora mucronata, Xylocarpus granatum, and Xylocarpus moluccensis. Appearance and geographical distribution, traditional uses, chemical composition, and biological studies related to antidiarrhoeal activity will be presented. This review reveals that there is limited scientific evidence supporting the traditional use of these plants. Most promising are the barks from D. peregrina, X. granatum and X. moluccensis which contain tannins and have shown promising results in antidiarrhoeal mice models. The leaves of P. pinnata also show potential. We suggest these plants should be exploited further as possible traditional herbal remedies against diarrhoea including studies on efficacy, optimal dosage and safety. PMID:23698166
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Wangensteen, Helle; Klarpås, Line; Alamgir, Mahiuddin; Samuelsen, Anne B C; Malterud, Karl E
2013-05-22
Diarrhoea is a common disease which causes pain and may be deadly, especially in developing countries. In Bangladesh, diarrhoeal diseases affect thousands of people every year, and children are especially vulnerable. Bacterial toxins or viral infections are the most common cause of the disease. The diarrhoea outbreaks are often associated with flood affected areas with contaminated drinking water and an increased risk of spreading the water-borne disease. Not surprisingly, plants found in the near surroundings have been taken into use by the local community as medicine to treat diarrhoeal symptoms. These plants are cheaper and more easily available than conventional medicine. Our question is: What is the level of documentation supporting the use of these plants against diarrhoea and is their consumption safe? Do any of these plants have potential for further exploration? In this review, we have choosen seven plant species that are used in the treatment of diarrhoea; Diospyros peregrina, Heritiera littoralis, Ixora coccinea, Pongamia pinnata, Rhizophora mucronata, Xylocarpus granatum, and Xylocarpus moluccensis. Appearance and geographical distribution, traditional uses, chemical composition, and biological studies related to antidiarrhoeal activity will be presented. This review reveals that there is limited scientific evidence supporting the traditional use of these plants. Most promising are the barks from D. peregrina, X. granatum and X. moluccensis which contain tannins and have shown promising results in antidiarrhoeal mice models. The leaves of P. pinnata also show potential. We suggest these plants should be exploited further as possible traditional herbal remedies against diarrhoea including studies on efficacy, optimal dosage and safety.
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Directory of Open Access Journals (Sweden)
Karl E. Malterud
2013-05-01
Full Text Available Diarrhoea is a common disease which causes pain and may be deadly, especially in developing countries. In Bangladesh, diarrhoeal diseases affect thousands of people every year, and children are especially vulnerable. Bacterial toxins or viral infections are the most common cause of the disease. The diarrhoea outbreaks are often associated with flood affected areas with contaminated drinking water and an increased risk of spreading the water-borne disease. Not surprisingly, plants found in the near surroundings have been taken into use by the local community as medicine to treat diarrhoeal symptoms. These plants are cheaper and more easily available than conventional medicine. Our question is: What is the level of documentation supporting the use of these plants against diarrhoea and is their consumption safe? Do any of these plants have potential for further exploration? In this review, we have choosen seven plant species that are used in the treatment of diarrhoea; Diospyros peregrina, Heritiera littoralis, Ixora coccinea, Pongamia pinnata, Rhizophora mucronata, Xylocarpus granatum, and Xylocarpus moluccensis. Appearance and geographical distribution, traditional uses, chemical composition, and biological studies related to antidiarrhoeal activity will be presented. This review reveals that there is limited scientific evidence supporting the traditional use of these plants. Most promising are the barks from D. peregrina, X. granatum and X. moluccensis which contain tannins and have shown promising results in antidiarrhoeal mice models. The leaves of P. pinnata also show potential. We suggest these plants should be exploited further as possible traditional herbal remedies against diarrhoea including studies on efficacy, optimal dosage and safety.
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Effects of air pollution on plant growth
Energy Technology Data Exchange (ETDEWEB)
Bleasadle, J K.A.
1959-01-01
The environment for plant growth is affected in three ways by the presence of coal smoke (1) by a reduction in the amount of light available to the plants, (2) by an alteration in soil conditions, and (3) by the contamination of the air by foreign gases. The smoke haze in or near industrial areas reduced the light available to plants for photosynthesis, thus reducing their growth rate. The tarry deposit on leaves further reduced the light available to the plant, and lowered the assimilation rate. It was generally thought that rain falling in or near industrial areas dissolved the predominantly acidic polluting gases from the air and leached bases from the soil. Rainwater collected showed a reduced number of soil bacteria, resulting in a reduction in the availability of plant nutrients. The most common and abundant gaseous pollutant in Britain was sulfur dioxide formed from the sulfur contained in coal. Concentrations of 0.5 parts per million induced symptoms of leaf scorch in many species. Results showed the yield of Aberystwyth 523 ryegrass was reduced when plants were grown continuously in air polluted with coal smoke. This affected the processes involving cell division. Coal smoke and sulfur also increased the rate of leaf senescence. This rate increased as the concentration of sulfur dioxide increased, or as the length of exposure per day to a standard concentration was increased. The leaves of evergreen trees and shrubs also aged more rapidly in conditions of pollution. 14 references.
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Plant odour plumes as mediators of plant-insect interactions.
Beyaert, Ivo; Hilker, Monika
2014-02-01
Insect olfactory orientation along odour plumes has been studied intensively with respect to pheromonal communication, whereas little knowledge is available on how plant odour plumes (POPs) affect olfactory searching by an insect for its host plants. The primary objective of this review is to examine the role of POPs in the attraction of insects. First, we consider parameters of an odour source and the environment which determine the size, shape and structure of an odour plume, and we apply that knowledge to POPs. Second, we compare characteristics of insect pheromonal plumes and POPs. We propose a 'POP concept' for the olfactory orientation of insects to plants. We suggest that: (i) an insect recognises a POP by means of plant volatile components that are encountered in concentrations higher than a threshold detection limit and that occur in a qualitative and quantitative blend indicating a resource; (ii) perception of the fine structure of a POP enables an insect to distinguish a POP from an unspecific odorous background and other interfering plumes; and (iii) an insect can follow several POPs to their sources, and may leave the track of one POP and switch to another one if this conveys a signal with higher reliability or indicates a more suitable resource. The POP concept proposed here may be a useful tool for research in olfactory-mediated plant-insect interactions. © 2013 The Authors. Biological Reviews © 2013 Cambridge Philosophical Society.
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Directory of Open Access Journals (Sweden)
BAMBANG HERO SAHARJO
2006-04-01
Full Text Available Biomass burning is the burning of the world’s living and dead vegetation, including grasslands, forests and agricultural lands following the harvest for land clearing and land-use change. One of the important information needed following this biomass burning is how long the burnt forest or land can be recovered, and how worst the changing occurred. Repeated burning occurred at the same place trend to clean the vegetation which leads to have the land with lower number and quality of species left. The research objective is to understand the vegetation changing following peat fires in the sapric peat type at the land preparation using belong to the local community located in the Pelalawan district, Riau province, Indonesia during the dry season in the year 2001. Before burning, logging, slashing, drying and burning the site was dominated by Uncaria glabrata at seedling stage, Ficus sundaica at sapling stage, Ficus sundaica at pole stage and Stenochlaena palustris at understorey. After logging, slashing and followed by 4 weeks drying then continued by burning with high flame temperature range from 900-1100oC, it had been found that 3-months following burning the site was dominated by Uncaria glabrata at seedling stage and Nephrolepis flaccigera at understorey while 6-months following burning the site was dominated by Parastemon uruphyllus at seedling stage and Erechites valeriantifolia at understorey stage.
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Composite harm to plants by sulfurous acid gas and oxidant
Energy Technology Data Exchange (ETDEWEB)
Matsushima, J
1971-01-01
The composite effects on plants of sulfur dioxide and ozone, SO/sub 2/ and PAN, SO/sub 2/ and nitrogen dioxide, and NO/sub 2/ and ozone were studied. Pinto bean plants were exposed to SO/sub 2/ or O/sub 3/ only, to each gas alternately, and to a mixture of the two. The degree of injury by the gas or gases was indicated in percentage by area of the leaves damaged. In cases where no geometric effect occurred the damage to the plant by the individual gas had been great; damage from the individual gas had been slight in these cases where such an effect was observed. The geometric effect is produced when the density of SO/sub 2/ is rather low, generally 0.05-0.25 ppm. A mixture of SO/sub 2/ and O/sub 3/ was applied to a tabacco plant; it affected fully grown leaves. In experiments on the composite effects of SO/sub 2/ and PAN on bean, tomato and pepper plants, PAN affected mainly young leaves while SO/sub 2/ affected mature ones. These effects were arithmetric rather then geometric. The SO/sub 2/ and NO/sub 2/ were also studied in the same manner. When SO/sub 2/ and NO/sub 2/ were mixed, a geometric effect was conspicuous in damage to vegetables, the symptoms of damage by either of the two appeared about the same, younger leaves being affected less. When treated with the two gases alternately, the damage was greater if the plants were first treated with NO/sub 2/; possible causes for this effect are discussed. No significant composite effect of NO/sub 2/ and O/sub 3/ was observed.
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Intra-specific downsizing of frugivores affects seed germination of fleshy-fruited plant species
Pérez-Méndez, Néstor; Rodríguez, Airam; Nogales, Manuel
2018-01-01
The loss of largest-bodied individuals within species of frugivorous animals is one of the major consequences of defaunation. The gradual disappearance of large-bodied frugivores is expected to entail a parallel deterioration in seed dispersal functionality if the remaining smaller-sized individuals are not so effective as seed dispersers. While the multiple impacts of the extinction of large bodied species have been relatively well studied, the impact of intraspecific downsizing (i.e. the extinction of large individuals within species) on seed dispersal has rarely been evaluated. Here we experimentally assessed the impact of body-size reduction in the frugivorous lizard Gallotia galloti (Lacertidae), an endemic species of the Canary Islands, on the seed germination patterns of two fleshy-fruited plant species (Rubia fruticosa and Withania aristata). Seed germination curves and the proportions of germinated seeds were compared for both plant species after being defecated by large-sized individuals and small-sized individuals. The data show that seeds of W. aristata defecated by larger-sized lizards germinated faster and in a higher percentage than those defecated by small-sized lizards, while no differences were found for R. fruticosa seeds. Our results suggest that disappearance of the largest individuals of frugivorous species may impair recruitment of some plant species by worsening seed germination. They also warn us of a potential cryptic loss of seed dispersal functionality on defaunated ecosystems, even when frugivorous species remain abundant.
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Slana, I.; Pribylova, R.; Kralova, A.; Pavlik, I.
2011-01-01
In this study, products from all steps of anaerobic digestion at a farm-scale biogas plant supplied with manure from paratuberculosis-affected dairy cattle were examined and quantified for the presence of the causal agent of paratuberculosis, Mycobacterium avium subsp. paratuberculosis, using culture and quantitative real-time PCR (qPCR). Viable M. avium subsp. paratuberculosis cells were detected using culture in fermentors for up to 2 months; the presence of M. avium subsp. paratuberculosis DNA (101 cells/g) was demonstrated in all anaerobic fermentors and digestate 16 months after initiation of work at a biogas plant, using IS900 qPCR. F57 qPCR was able to detect M. avium subsp. paratuberculosis DNA (102 cells/g) at up to 12 months. According to these results, a fermentation process that extended beyond 2 months removed all viable M. avium subsp. paratuberculosis cells and therefore rendered its product M. avium subsp. paratuberculosis free. However, M. avium subsp. paratuberculosis DNA was found during all the examined periods (more than 1 year), which could be explained by either residual DNA being released from dead cells or by the presence of viable cells whose amount was under the limit of cultivability. As the latter hypothesis cannot be excluded, the safety of the final products of digestion used for fertilization or animal bedding cannot be defined, and further investigation is necessary to confirm or refute this risk. PMID:21398476
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Madejón, P; Murillo, J M; Marañón, T; Cabrera, F; Soriano, M A
2003-05-20
The failure of a tailing pond dam at the Aznalcóllar pyrite mine (SW Spain) in April 1998 released a toxic spill affecting approximately 4300 ha along the Agrio and Guadiamar valleys. Two years later, we have studied yield and concentration of mineral nutrients and trace elements in sunflower plants grown in the spill-affected soil, and in an adjacent unaffected soil as comparison. The study has been carried out in plants at seedling (V4) and mature (R8) stages. Shoot and root biomass of sunflower seedlings was significantly smaller in the affected soil than in the unaffected soil, but there was no significant difference at the mature stage. Oil production was greater in the spill-affected plants. We have not detected any 'fertilising' effect caused by the acid waters of the spill on the main nutrient (N, P and Ca) acquisition, as documented in 1998 for sunflower plants flooded by the spill. Sunflower plants growing in the spill-affected soil reached adequate levels of nutrients. None of the trace elements measured-As, Cd, Cu, Pb and Tl-reached levels either phytotoxic or toxic for humans or animals in seeds and the above-ground part of the spill-affected plants. We evaluate the potential use of sunflower plants for phytoremediation. The potential for phytoextraction is very low; however, it may be used for soil conservation. The production of oil (usable for industrial purposes) may add some value to this crop.
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Studies on saponin production in tropical medicinal plants Maesa argentea and Maesa lanceolata
Faizal, Ahmad; Geelen, Danny
2015-09-01
The continuous need for new compounds with important medicinal activities has lead to the identification and characterization of various plant-derived natural products. As a part of this program, we studied the saponin production from two tropical medicinal plants Maesa argentea and M. lanceolata and evaluated several treatments to enhance their saponin production. In this experiment, we present the analyses of saponin production from greenhouse grown plants by means of TLC and HPLC-MS. We observed that the content of saponin from these plants varied depending on organ and physiological age of the plants. In addition, the impact of elicitors on saponin accumulation on in vitro grown plants was analyzed using TLC. The production of saponin was very stable and not affected by treatment with methyl jasmonate, and salicylic acid. In conclusion, Maesa saponins are constitutively produced in plants and the level of these compounds in plants is mainly affected by the developmental or physiological stage.
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Quality of medicinal plants traditionally used in Sudan as affected by ionizing radiation treatments
Energy Technology Data Exchange (ETDEWEB)
Musa, H A. A. [Department of Botany and Agricultural Biotechnology, Faculty of Agriculture, University of Khartoum, Khartoum (Sudan)
2009-11-15
This investigation was conducted to study the effect of gamma-radiation doses of 5, 10 and 15 KGy on the microbial and chemical quality as well as antioxidant activity of nine medical plants from 8 plant species grown in Sudan. The plant materials were collected from the country-side of Khartoum State as well as from local markets. Plant parts were selected according to their traditional uses as medicinal plants. Irradiation treatment was carried out or dried ground samples using doses of 5,10, 15 KGy from experimental cobalt-60 gamma source. Plants extracts were prepared using 80% methanol. The control and irradiated samples were analyzed for total bacterial count (cfu/g), secondary compounds, tannin content, total phenol, and antioxidant activity. Tannins, flavonoids, glycosides, anthraquinones, saponin and phenols were evaluated through major compounds in extracts. The total bacterial count indicated that the non- irradiated samples of Trigonella foenum-graecum L., Cassia senna (pods), Cassia senna (leaves), Acacia nilotica L., Brassica nigra L. Koch, Lepidium sativum L., Cymbopogon citratus and Hibiscus sabdariffa L. were highly contaminated with bacteria. The sample of Cymbopogon schoenanthus L. showed a lower count of bacteria (9x10'' 3 Cfu/g), which did not exceed the acceptable level. The samples irradiated with 5, 10 and 15 KGy of gamma radiation dose had significantly lower bacterial counts than the non-irradiated control. The highest sensitivity to gamma rays at 5 KGy dose was observed in Trigonella foenum-graecum L. and Acacia nilotica L. while the lowest sensitivity was in Cymbopogon schoenanthus L. At 15 KGy dose Hibiscus sabdariffa L. and Cymbopogon citratus showed complete absence of microorganisms. The highest reduction in tannin content (mg/L catechin) due to irradiation with 15 KGy dose was observed in Cymbopogon citratus, followed by Cymbopogon schoenanthus L., Cassia senna L. leaves Acacia nilotica L. and Hibiscus sabdariffa L.. Irradiation
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Quality of medicinal plants traditionally used in Sudan as affected by ionizing radiation treatments
International Nuclear Information System (INIS)
Musa, H. A. A.
2009-11-01
This investigation was conducted to study the effect of gamma-radiation doses of 5, 10 and 15 KGy on the microbial and chemical quality as well as antioxidant activity of nine medical plants from 8 plant species grown in Sudan. The plant materials were collected from the country-side of Khartoum State as well as from local markets. Plant parts were selected according to their traditional uses as medicinal plants. Irradiation treatment was carried out or dried ground samples using doses of 5,10, 15 KGy from experimental cobalt-60 gamma source. Plants extracts were prepared using 80% methanol. The control and irradiated samples were analyzed for total bacterial count (cfu/g), secondary compounds, tannin content, total phenol, and antioxidant activity. Tannins, flavonoids, glycosides, anthraquinones, saponin and phenols were evaluated through major compounds in extracts. The total bacterial count indicated that the non- irradiated samples of Trigonella foenum-graecum L., Cassia senna (pods), Cassia senna (leaves), Acacia nilotica L., Brassica nigra L. Koch, Lepidium sativum L., Cymbopogon citratus and Hibiscus sabdariffa L. were highly contaminated with bacteria. The sample of Cymbopogon schoenanthus L. showed a lower count of bacteria (9x10'' 3 Cfu/g), which did not exceed the acceptable level. The samples irradiated with 5, 10 and 15 KGy of gamma radiation dose had significantly lower bacterial counts than the non-irradiated control. The highest sensitivity to gamma rays at 5 KGy dose was observed in Trigonella foenum-graecum L. and Acacia nilotica L. while the lowest sensitivity was in Cymbopogon schoenanthus L. At 15 KGy dose Hibiscus sabdariffa L. and Cymbopogon citratus showed complete absence of microorganisms. The highest reduction in tannin content (mg/L catechin) due to irradiation with 15 KGy dose was observed in Cymbopogon citratus, followed by Cymbopogon schoenanthus L., Cassia senna L. leaves Acacia nilotica L. and Hibiscus sabdariffa L.. Irradiation
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Osmotic potential of Zinnia elegans plant material affects the yield ...
African Journals Online (AJOL)
To examine whether the growth conditions that determine leaf osmolarity (LO) affect the final %TE, we used three light intensities (50, 70 and 100 μmol.m-2s-1) and three electrical conductivity (EC) levels (EC 2, 4 and 6 dS.m-1 ) in hydroponic systems to induce different osmolarities in leaf materials from two cultivars (cvs) of ...
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Roan antelope ( Hippotragus equinus desmarest1804) food plants ...
African Journals Online (AJOL)
The habitat changes in Borgu sector of Kainji lake National Park affects the food plants and feeding habits of roan antelope. The changes which are usually seasonal variation in climate and the effect of uncontrolled bush burning by poachers. The objectives of the study were to determine the food plants and feeding habits ...
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International Nuclear Information System (INIS)
Akhtar, L.H.; Gorham, J.; Siddiqui, S.Z.; Jamil, M.; Arshad, M.
2002-01-01
Salinity affects the physiological and biochemical processes of the plants in a variety of ways. In this manuscript, variability in plant, with respect to salinity-tolerance and morphological adaptations in plants for salinity-tolerance, have been discussed. Salinity effects on growth of plants, cell membranes, proteins, sugars, nucleic acids, starch, cell sap, transpiration, stomatal conductance, pollen viability, Co/sub 2/ assimilation, chlorophyll, photosynthesis and enzymes have been reviewed. Proline and glycinebetaine accumulation, localisation in the cell and their physiological role under salt-stress has been presented. Cellular mechanism of salt-tolerance and role of calcium in salt-stress have been reviewed. The possible approaches to deal with all types of stresses have been suggested. (author)
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DEFF Research Database (Denmark)
Stranne, Maria
The plant cell wall is a dynamic structure and it is involved in regulating a number of physiological features of plants such as physical strength, growth, cell differentiation, intercellular communication, water movement and defense responses. Pectins constitute a major class of plant cell wall...... polysaccharides and consist of backbones rich in galacturonic acids, which are decorated with a range of functional groups including acetyl esters and arabinan sidechains. Although much effort has been made to uncover biological functions of pectins in plants and remarkable progresses have taken place, many...... aspects remain elusive. Studies described in this thesis aimed at gaining new insights into the biological roles of pectin acetylation and arabinosylation in the model plant Arabidopsis thaliana. The thesis consists of four chapters: physiological characterization of cell wall mutants affected in cell...
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DEFF Research Database (Denmark)
Mortensen, Hanne Skovgaard; Dupont, Yoko; Olesen, Jens Mogens
2008-01-01
native plant species in Guam. We investigated flower visitation, seed set and germination in two native plants, the mangrove tree Bruguiera gymnorrhiza and the forest tree Erythrina variegata var. orientalis. Both species are bird-pollinated. Studies were conducted on two Mariana islands, Guam (with high...... mutualistic interactions, which may, in turn, result in a lower recruitment of native plants. Thus, the treesnake affects not only potential prey species, but its effects cascade through the entire ecosystem on Guam. Conservation actions should be directed towards an improved recruitment (artificial...... pollination, planting) of the affected plant species....
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International Nuclear Information System (INIS)
Kurdali, F.; Al-Shamma'a, M.
2006-08-01
A pot experiment was conducted throughout two successive years to determine the impact of adding four rates of nitrogen (0, 60, 120 and 180 kg N/ha) in the form of Leucaena leucocephala (lam.) de Wit green manure as affected by different time (T0, T15 and T30) of application (just before sowing, 15 and 30 days before sowing, respectively) on the performance of sorghum (Sorghum bicolor L.) using the indirect N-15 isotopic dilution technique. Results showed that leucaena leaves, used as a green manure, significantly increased dry matter production and N yield of sorghum. The effect was more pronounced in panicles than shoots. In the first year, N recoveries in sorghum of the total N contained in leucaena green manure ranged between 17-24% in T0, 14-24% in T15 and 15-19% in T30. The highest N recovery value was obtained in lowest rate of n treatment (N 60 ). Moreover, soil incorporated with leucaena green manure one month before planting enhanced both soil and mineral N fertilizer in sorghum plants. In the second year, total N uptake in sorghum (eg., panicles and the entire plant) increased with increasing amounts of N added as a leucaena green manure. N recoveries in sorghum ranged between 26-47% in T0, about 24% in T15 and 23-325 in T30 of the total N contained in leucaena green manure (LGM). As shown in the first year, the highest value of N recovery was obtained in lowest rate of N treatment. The beneficial effects of leucaena green manure on dry matter and N yield in sorghum was attributed not only to the additional N availability to the plant, but also to effects on the enhancement of soil N uptake, particularly when the incorporation was made before a sufficient time from sowing. The beneficial effect of green manuring with leucaena leaves at T15 and T30 was mainly resulted from enhancement of N uptake from this added material, as well as from soil and fertilizer N; whereas, it was only attributed to N uptake from green manure in the T0 treatment. Incorporation
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International Nuclear Information System (INIS)
Kurdali, F.; Al-Shamma'a, M.
2007-01-01
A pot experiment was conducted throughout two successive years to determine the impact of adding four rates of nitrogen (0, 60, 120 and 180 kg N/ha) in the form of Leucaena leucocephala (lam.) de Wit green manure as affected by different time (T0, T15 and T30) of application (just before sowing, 15 and 30 days before sowing, respectively) on the performance of sorghum (Sorghum bicolor L.) using the indirect N-15 isotopic dilution technique. Results showed that leucaena leaves, used as a green manure, significantly increased dry matter production and N yield of sorghum. The effect was more pronounced in panicles than shoots. In the first year, N recoveries in sorghum of the total N contained in leucaena green manure ranged between 17-24% in T0, 14-24% in T15 and 15-19% in T30. The highest N recovery value was obtained in lowest rate of n treatment (N60). Moreover, soil incorporated with leucaena green manure one month before planting enhanced both soil and mineral N fertilizer in sorghum plants. In the second year, total N uptake in sorghum (eg., panicles and the entire plant) increased with increasing amounts of N added as a leucaena green manure. N recoveries in sorghum ranged between 26-47% in T0, about 24% in T15 and 23-325 in T30 of the total N contained in leucaena green manure (LGM). As shown in the first year, the highest value of N recovery was obtained in lowest rate of N treatment. The beneficial effects of leucaena green manure on dry matter and N yield in sorghum was attributed not only to the additional N availability to the plant, but also to effects on the enhancement of soil N uptake, particularly when the incorporation was made before a sufficient time from sowing. The beneficial effect of green manuring with leucaena leaves at T15 and T30 was mainly resulted from enhancement of N uptake from this added material, as well as from soil and fertilizer N. Whereas, it was only attributed to N uptake from green manure in the T0 treatment. Incorporation
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Hydrologic alteration affects aquatic plant assemblages in an arid-land river
Vinson, Mark; Hestmark, Bennett; Barkworth, Mary E.
2014-01-01
We evaluated the effects of long-term flow alteration on primary-producer assemblages. In 1962, Flaming Gorge Dam was constructed on the Green River. The Yampa River has remained an unregulated hydrologically variable river that joins the Green River 100 km downstream from Flaming Gorge Dam. In the 1960s before dam construction only sparse occurrences of two macroalgae, Cladophora and Chara, and no submerged vascular plants were recorded in the Green and Yampa rivers. In 2009–2010, aquatic plants were abundant and widespread in the Green River from the dam downstream to the confluence with the Yampa River. The assemblage consisted of six vascular species, Elodea canadensis, Myriophyllum sibiricum, Nasturtium officinale,Potamogeton crispus, Potamogeton pectinatus, and Ranunculus aquatilis, the macroalgae Chara and Cladophora, and the bryophyte, Amblystegium riparium. In the Green River downstream from the Yampa River, and in the Yampa River, only sparse patches of Chara and Cladophora growing in the splash zone on boulders were collected. We attribute the observed changes in the Green River to an increase in water transparency and a reduction in suspended and bed-load sediment and high flow disturbances. The lack of hydrophyte colonization downstream from the confluence with the Yampa River has implications for understanding tributary amelioration of dam effects and for designing more natural flow-regime schedules downstream from large dams.
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THE USE OF PLANTS TO PROTECT PLANTS AND FOOD AGAINST FUNGAL PATHOGENS: A REVIEW.
Shuping, D S S; Eloff, J N
2017-01-01
Plant fungal pathogens play a crucial role in the profitability, quality and quantity of plant production. These phytopathogens are persistent in avoiding plant defences causing diseases and quality losses around the world that amount to billions of US dollars annually. To control the scourge of plant fungal diseases, farmers have used fungicides to manage the damage of plant pathogenic fungi. Drawbacks such as development of resistance and environmental toxicity associated with these chemicals have motivated researchers and cultivators to investigate other possibilities. Several databases were accessed to determine work done on protecting plants against plant fungal pathogens with plant extracts using search terms "plant fungal pathogen", "plant extracts" and "phytopathogens". Proposals are made on the best extractants and bioassay techniques to be used. In addition to chemical fungicides, biological agents have been used to deal with plant fungal diseases. There are many examples where plant extracts or plant derived compounds have been used as commercial deterrents of fungi on a large scale in agricultural and horticultural setups. One advantage of this approach is that plant extracts usually contain more than one antifungal compound. Consequently the development of resistance of pathogens may be lower if the different compounds affect a different metabolic process. Plants cultivated using plants extracts may also be marketed as organically produced. Many papers have been published on effective antimicrobial compounds present in plant extracts focusing on applications in human health. More research is required to develop suitable, sustainable, effective, cheaper botanical products that can be used to help overcome the scourge of plant fungal diseases. Scientists who have worked only on using plants to control human and animal fungal pathogens should consider the advantages of focusing on plant fungal pathogens. This approach could not only potentially increase
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Indispensable Role of Proteases in Plant Innate Immunity.
Balakireva, Anastasia V; Zamyatnin, Andrey A
2018-02-23
Plant defense is achieved mainly through the induction of microbe-associated molecular patterns (MAMP)-triggered immunity (MTI), effector-triggered immunity (ETI), systemic acquired resistance (SAR), induced systemic resistance (ISR), and RNA silencing. Plant immunity is a highly complex phenomenon with its own unique features that have emerged as a result of the arms race between plants and pathogens. However, the regulation of these processes is the same for all living organisms, including plants, and is controlled by proteases. Different families of plant proteases are involved in every type of immunity: some of the proteases that are covered in this review participate in MTI, affecting stomatal closure and callose deposition. A large number of proteases act in the apoplast, contributing to ETI by managing extracellular defense. A vast majority of the endogenous proteases discussed in this review are associated with the programmed cell death (PCD) of the infected cells and exhibit caspase-like activities. The synthesis of signal molecules, such as salicylic acid, jasmonic acid, and ethylene, and their signaling pathways, are regulated by endogenous proteases that affect the induction of pathogenesis-related genes and SAR or ISR establishment. A number of proteases are associated with herbivore defense. In this review, we summarize the data concerning identified plant endogenous proteases, their effect on plant-pathogen interactions, their subcellular localization, and their functional properties, if available, and we attribute a role in the different types and stages of innate immunity for each of the proteases covered.
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Overexpression of maize anthocyanin regulatory gene Lc affects rice fertility.
Li, Yuan; Zhang, Tao; Shen, Zhong-Wei; Xu, Yu; Li, Jian-Yue
2013-01-01
Seventeen independent transgenic rice plants with the maize anthocyanin regulatory gene Lc under control of the CaMV 35S promoter were obtained and verified by molecular identification. Ten plants showed red spikelets during early development of florets, and the degenerate florets were still red after heading. Additionally, these plants exhibited intense pigmentation on the surface of the anther and the bottom of the ovary. They were unable to properly bloom and were completely sterile. Following pollination with normal pollen, these plants yielded red caryopses but did not mature normally. QRT-PCR analysis indicated that mRNA accumulation of the CHS-like gene encoding a chalcone synthase-related protein was increased significantly in the sterile plant. This is the first report to suggest that upregulation of the CHS gene expression may result in rice sterility and affect the normal development of rice seeds.
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Miki, Takeshi; Ushio, Masayuki; Fukui, Shin; Kondoh, Michio
2010-08-10
Theory and empirical evidence suggest that plant-soil feedback (PSF) determines the structure of a plant community and nutrient cycling in terrestrial ecosystems. The plant community alters the nutrient pool size in soil by affecting litter decomposition processes, which in turn shapes the plant community, forming a PSF system. However, the role of microbial decomposers in PSF function is often overlooked, and it remains unclear whether decomposers reinforce or weaken litter-mediated plant control over nutrient cycling. Here, we present a theoretical model incorporating the functional diversity of both plants and microbial decomposers. Two fundamental microbial processes are included that control nutrient mineralization from plant litter: (i) assimilation of mineralized nutrient into the microbial biomass (microbial immobilization), and (ii) release of the microbial nutrients into the inorganic nutrient pool (net mineralization). With this model, we show that microbial diversity may act as a buffer that weakens plant control over the soil nutrient pool, reversing the sign of PSF from positive to negative and facilitating plant coexistence. This is explained by the decoupling of litter decomposability and nutrient pool size arising from a flexible change in the microbial community composition and decomposition processes in response to variations in plant litter decomposability. Our results suggest that the microbial community plays a central role in PSF function and the plant community structure. Furthermore, the results strongly imply that the plant-centered view of nutrient cycling should be changed to a plant-microbe-soil feedback system, by incorporating the community ecology of microbial decomposers and their functional diversity.
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The FRIABLE1 gene product affects cell adhesion in Arabidopsis.
Directory of Open Access Journals (Sweden)
Lutz Neumetzler
Full Text Available Cell adhesion in plants is mediated predominantly by pectins, a group of complex cell wall associated polysaccharides. An Arabidopsis mutant, friable1 (frb1, was identified through a screen of T-DNA insertion lines that exhibited defective cell adhesion. Interestingly, the frb1 plants displayed both cell and organ dissociations and also ectopic defects in organ separation. The FRB1 gene encodes a Golgi-localized, plant specific protein with only weak sequence similarities to known proteins (DUF246. Unlike other cell adhesion deficient mutants, frb1 mutants do not have reduced levels of adhesion related cell wall polymers, such as pectins. Instead, FRB1 affects the abundance of galactose- and arabinose-containing oligosaccharides in the Golgi. Furthermore, frb1 mutants displayed alteration in pectin methylesterification, cell wall associated extensins and xyloglucan microstructure. We propose that abnormal FRB1 action has pleiotropic consequences on wall architecture, affecting both the extensin and pectin matrices, with consequent changes to the biomechanical properties of the wall and middle lamella, thereby influencing cell-cell adhesion.
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Williams, Wyatt I; Friedman, Jonathan M; Gaskin, John F; Norton, Andrew P
2014-01-01
Evolution has contributed to the successful invasion of exotic plant species in their introduced ranges, but how evolution affects particular control strategies is still under evaluation. For instance, classical biological control, a common strategy involving the utilization of highly specific natural enemies to control exotic pests, may be negatively affected by host hybridization because of shifts in plant traits, such as root allocation or chemical constituents. We investigated introgressi...
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Directory of Open Access Journals (Sweden)
Nurmi ePangesti
2013-10-01
Full Text Available Plants are members of complex communities and function as a link between above- and below-ground organisms. Associations between plants and soil-borne microbes commonly occur and have often been found beneficial for plant fitness. Root-associated microbes may trigger physiological changes in the host plant that influence interactions between plants and aboveground insects at several trophic levels. Aboveground, plants are under continuous attack by insect herbivores and mount multiple responses that also have systemic effects on belowground microbes. Until recently, both ecological and mechanistic studies have mostly focused on exploring these below- and above-ground interactions using simplified systems involving both single microbe and herbivore species, which is far from the naturally occurring interactions. Increasing the complexity of the systems studied is required to increase our understanding of microbe - plant - insect interactions and to gain more benefit from the use of non-pathogenic microbes in agriculture. In this review, we explore how colonization by either single non-pathogenic microbe species or a community of such microbes belowground affects plant growth and defense and how this affects the interactions of plants with aboveground insects at different trophic levels. Moreover, we review how plant responses to foliar herbivory by insects belonging to different feeding guilds affect interactions of plants with non-pathogenic soil-borne microbes. The role of phytohormones in coordinating plant growth, plant defenses against foliar herbivores while simultaneously establishing associations with non-pathogenic soil microbes is discussed.
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Gamma-Ray Doses Affected on Alfalfa (Medicago sativa L.)
International Nuclear Information System (INIS)
Zayed, E.M; Tarrad, M.M.; Abd El-Daem, G.A.N.A.
2013-01-01
Field experiments were conducted at the experimental from, Nuclear Research Center at Inshas. Atomic Energy Authority (AEA) at Egypt during 2011– 2012 growing seasons on alfalfa genotype. The aim of this investigation to evaluate the effect of different gamma ray doses (100-300 Gy) on the alfalfa yield and related traits. Seeds lots of alfalfa genotype were subjected to five gamma ray treatments (100,150,200,250 and 300 Gray). Over all cuts, the dose treatment 300 Gy increased the majority of studied traits i.e., plant height, No. of shoots/plant, fresh weight/plant, fresh yield/Fadden and dry weight yield/fed. The results observed indicated that. In addition, dose of 200 and 250 Gy increased No. of leaves /plant, No. of shoots/plant, stem diameter and fresh weight /plant. However, the plant dry weight was decreased by all doses used and over all cuts, but the dose of 100 and 150 Gy increased leaves /stem ratio. Meanwhile, the later cuts were more affected by irradiation treatments than the earlier ones. In general, the low doses had negative effects on yield traits, but, the relatively high doses exhibited an increase in yield traits
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Farré, Maria José; Döderer, Katrin; Hearn, Laurence; Poussade, Yvan; Keller, Jurg; Gernjak, Wolfgang
2011-01-30
N-nitrosodimethylamine (NDMA) can be formed when secondary effluents are disinfected by chloramines. By means of bench scale experiments this paper investigates operational parameters than can help Advanced Water Treatment Plants (AWTPs) to reduce the formation of NDMA during the production of high quality recycled water. The formation of NDMA was monitored during a contact time of 24h using dimethylamine as NDMA model precursor and secondary effluent from wastewater treatment plants. The three chloramine disinfection strategies tested were pre-formed and in-line formed monochloramine, and pre-formed dichloramine. Although the latter is not employed on purpose in full-scale applications, it has been suggested as the main contributing chemical generating NDMA during chloramination. After 24h, the NDMA formation decreased in both matrices tested in the order: pre-formed dichloramine>in-line formed monochloramine≫pre-formed monochloramine. The most important parameter to consider for the inhibition of NDMA formation was the length of contact time between disinfectant and wastewater. Formation of NDMA was initially inhibited for up to 6h with concentrations consistently NDMA concentrations were reduced by a factor of 20 by optimizing the disinfection strategy. Copyright © 2010 Elsevier B.V. All rights reserved.
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NMR metabolomics of esca disease-affected Vitis vinifera cv. Alvarinho leaves.
Lima, Marta R M; Felgueiras, Mafalda L; Graça, Gonçalo; Rodrigues, João E A; Barros, António; Gil, Ana M; Dias, Alberto C P
2010-09-01
Esca is a destructive disease that affects vineyards leading to important losses in wine production. Information about the response of Vitis vinifera plants to this disease is scarce, particularly concerning changes in plant metabolism. In order to study the metabolic changes in Vitis plants affected by esca, leaves from both infected and non-affected cordons of V. vinifera cv. Alvarinho (collected in the Vinho Verde region, Portugal) were analysed. The metabolite composition of leaves from infected cordons with visible symptoms [diseased leaves (dl)] and from asymptomatic cordons [healthy leaves (hl)] was evaluated by 1D and 2D (1)H-nuclear magnetic resonance (NMR) spectroscopy. Principal component analysis (PCA) of the NMR spectra showed a clear separation between dl and hl leaves, indicating differential compound production due to the esca disease. NMR/PCA analysis allowed the identification of specific compounds characterizing each group, and the corresponding metabolic pathways are discussed. Altogether, the study revealed a significant increase of phenolic compounds in dl, compared with hl, accompanied by a decrease in carbohydrates, suggesting that dl are rerouting carbon and energy from primary to secondary metabolism. Other metabolic alterations detected comprised increased levels of methanol, alanine, and gamma-aminobutyric acid in dl, which might be the result of the activation of other defence mechanisms.
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Piovesan, Mônica; Specht, Alexandre; Carneiro, Eduardo; Paula-Moraes, Silvana Vieira; Casagrande, Mirna Martins
2018-03-01
The identification of factors responsible for the population dynamics is fundamental for pest management, since losses can reach 18% of annual production. Besides regular seasonal environmental factors and crop managements, additional supra-annual meteorological phenomena can also affect population dynamics, although its relevance has been rarely investigated. Among crop pests, Spodoptera stands out due to its worldwide distribution, high degree of polyphagy, thus causing damages in several crops in the world. Aiming to distinguish the relevance of different factors shaping population dynamics of Spodoptera in an ecosystem constituted of dry and rainy seasons, the current study used circular statistics to identify phenological patterns and test if its population fluctuation is driven by El Niño-Southern Oscillation (ENSO) effect, seasonal meteorological parameters, and/or host plant availability. Samplings were done in an intercropping system, in the Brazilian Savanna, during the new moon cycles between July/2013 and June/2016. Species were recorded all year round, but demonstrated differently non-uniform distribution, being concentrated in different seasons of the year. Population fluctuations were mostly affected by the ENSO intensity, despite the contrasting seasonal meteorological variation or host plant availability in a 400-m radius. Studies involving the observation of supra-annual phenomena, although rare, reach similar conclusions in relation to Neotropical insect fauna. Therefore, it is paramount to have long-term sampling studies to obtain a more precise response of the pest populations towards the agroecosystem conditions.
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DEFF Research Database (Denmark)
Saj, S.; Mikola, J.; Ekelund, Flemming
2008-01-01
It is known that plant species can induce development of different soil decomposer communities and that they differ in their influence on organic matter decomposition and N mineralization in soil. However, no study has so far assessed whether these two observations are related to each other. Base...... that plant traits such as competitive ability for soil mineral N were more important for plant uptake of litter-N than those that directly affected the growth of soil decomposers.......It is known that plant species can induce development of different soil decomposer communities and that they differ in their influence on organic matter decomposition and N mineralization in soil. However, no study has so far assessed whether these two observations are related to each other. Based...... on the hypothesis that root-induced growth of soil decomposers leads to accelerated decomposition of SOM and increased plant N availability in soil, we predicted that (1) among a set of grassland plants the abundance of soil decomposers in the plant rhizosphere is positively associated with plant N uptake from soil...
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Theuwissen, Elke; Mensink, Ronald P
2007-03-01
Intake of food products rich in water-soluble fiber beta-glucan and products enriched with plant stanol esters lower serum cholesterol. Combining 2 functional food ingredients into one food product may achieve additional reductions of serum cholesterol. Our objective was to investigate the effects of a simultaneous intake of beta-glucan plus plant stanol esters on lipid metabolism in mildly hypercholesterolemic volunteers. In a randomized, controlled, 3-period crossover study, 40 mildly hypercholesterolemic men and women received muesli in random order twice a day for 4 wk, which provided, in total, 5 g control fiber from wheat (control muesli), 5 g oat beta-glucan (beta-glucan muesli), or 5 g oat beta-glucan plus 1.5 g plant stanols (combination muesli). beta-Glucan muesli decreased serum LDL cholesterol by 5.0% compared with control muesli (P = 0.013). Combination muesli reduced LDL cholesterol by 9.6% compared with control muesli (P < 0.001), and by 4.4% compared with beta-glucan muesli (P = 0.036). Serum HDL cholesterol and triacylglycerol concentrations did not differ after the 3 treatments. Compared with control muesli, beta-glucan muesli increased bile acid synthesis (P = 0.043) and decreased cholesterol absorption (P = 0.011). Addition of plant stanols did not influence bile acid synthesis but decreased cholesterol absorption (P < 0.001) and raised cholesterol synthesis (P = 0.016) compared with control muesli, and the plant stanols decreased cholesterol absorption compared with beta-glucan muesli (P = 0.004). The combination muesli decreased serum concentrations of sitostanol compared with control muesli (P = 0.010). Plasma concentrations of lipid-soluble antioxidants did not differ after the 3 treatments. beta-Glucan muesli effectively lowered serum LDL cholesterol concentrations. The addition of plant stanol esters to beta-glucan-enriched muesli further lowered serum LDL cholesterol, although effects were slightly less than predicted.
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Impact of tillage, plant population and mulches on phenological characters of maize
International Nuclear Information System (INIS)
Gul, B.; Khan, M.A.; Khan, H.
2014-01-01
Field experiments were conducted during 2006 and 2007 in Peshawar, using open pollinated maize variety Azam in RCB design having 3 factors viz., tillage, maize populations and mulches with split-split plot arrangements. Tillage levels (zero and conventional) were assigned to the main plots, populations (90000, 60000 and 30000 plants ha/sup -1/) to sub-plots and four types of mulches (weeds mulch, black plastic mulch, white plastic mulch and mungbean as living mulch), a hand weeding and a weedy check were allotted to sub-sub plots, respectively. Data were recorded on days to tasseling, days to silking, days to maturity, leaf area of maize plant-1 (cm/sub 2/) and plant height (cm). Tillage affected leaf area of maize, where zero tillage resulted lower leaf area of 4094 cm/sub 2/ compared to conventional tillage (4722 cm/sub 2/). Different levels of plant populations affected all the physiological parameters. Days to tasseling, silking and maturity were more in higher plant population as compared to medium and lower plant population. Similarly, minimum leaf area plant-1 was recorded in higher plant population (3894 cm/sub 2/) than medium and lower plant population of 4398 and 4932 cm/sub 2/, respectively. Maximum plant height was recorded in hand weeding treatment (173 cm). However, it was statistically at par with black plastic mulch (171 cm), followed by weeds mulch (162 cm) and white plastic mulch (161 cm) as compared to weedy check (152 cm). Based on two years study it is suggested that even if tillage options and plant populations are a part of the weed management program, it should not be used as a sole management tool, as both have a negative impact on the phenological parameters of maize which subsequently affected the final yield and must be integrated and supplemented with other control methods. (author)