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Sample records for limiting post-logging seedling

  1. Linking carbon and water limitations to drought-induced mortality of Pinus flexilis seedlings

    Science.gov (United States)

    Reinhardt, Keith; Germino, Matthew J.; Kueppers, Lara M.; Domec, Jean-Christophe; Mitton, Jeffry

    2015-01-01

    Survival of tree seedlings at high elevations has been shown to be limited by thermal constraints on carbon balance, but it is unknown if carbon relations also limit seedling survival at lower elevations, where water relations may be more important. We measured and modeled carbon fluxes and water relations in first-year Pinus flexilis seedlings in garden plots just beyond the warm edge of their natural range, and compared these with dry-mass gain and survival across two summers. We hypothesized that mortality in these seedlings would be associated with declines in water relations, more so than with carbon-balance limitations. Rather than gradual declines in survivorship across growing seasons, we observed sharp, large-scale mortality episodes that occurred once volumetric soil-moisture content dropped below 10%. By this point, seedling water potentials had decreased below −5 MPa, seedling hydraulic conductivity had decreased by 90% and seedling hydraulic resistance had increased by >900%. Additionally, non-structural carbohydrates accumulated in aboveground tissues at the end of both summers, suggesting impairments in phloem-transport from needles to roots. This resulted in low carbohydrate concentrations in roots, which likely impaired root growth and water uptake at the time of critically low soil moisture. While photosynthesis and respiration on a leaf area basis remained high until critical hydraulic thresholds were exceeded, modeled seedling gross primary productivity declined steadily throughout the summers. At the time of mortality, modeled productivity was insufficient to support seedling biomass-gain rates, metabolism and secondary costs. Thus the large-scale mortality events that we observed near the end of each summer were most directly linked with acute, episodic declines in plant hydraulic function that were linked with important changes in whole-seedling carbon relations.

  2. Root carbon reserve dynamics in aspen seedlings: does simulated drought induce reserve limitation?

    Science.gov (United States)

    Galvez, David A; Landhäusser, S M; Tyree, M T

    2011-03-01

    In a greenhouse study we quantified the gradual change of gas exchange, water relations and root reserves of aspen (Populus tremuloides Michx.) seedlings growing over a 3-month period of severe water stress. The aim of the study was to quantify the complex interrelationship between growth, water and gas exchange, and root carbon (C) dynamics. Various growth, gas exchange and water relations variables in combination with root reserves were measured periodically on seedlings that had been exposed to a continuous drought treatment over a 12-week period and compared with well-watered seedlings. Although gas exchange and water relations parameters significantly decreased over the drought period in aspen seedlings, root reserves did not mirror this trend. During the course of the experiment roots of aspen seedlings growing under severe water stress showed a two orders of magnitude increase in sugar and starch content, and roots of these seedlings contained more starch relative to sugar than those in non-droughted seedlings. Drought resulted in a switch from growth to root reserves storage which indicates a close interrelationship between growth and physiological variables and the accumulation of root carbohydrate reserves. Although a severe 3-month drought period created physiological symptoms of C limitation, there was no indication of a depletion of root C reserve in aspen seedlings.

  3. Why Seedlings Die: Linking Carbon and Water Limitations to Mechanisms of Mortality During Establishment in Conifer Seedlings

    Science.gov (United States)

    Reinhardt, K.; Germino, M. J.; Kueppers, L. M.; Mitton, J.; Castanha, C.

    2012-12-01

    BACKGROUND Recent ecophysiological studies aimed at explaining adult tree mortality during drought have examined the carbon (C)-exhaustion compared to the hydraulic-failure hypotheses for death. Prolonged drought leads to durations of stomatal closure (and thus limited C gain), which could result in long periods of negative C balance and fatal reductions in whole-plant C reserves (i.e., available non-structural carbohydrates ["NSC"]). Alternatively, C reserves may not decrease much but could become increasingly inaccessible to sink tissues in long dry-periods due to impediments to translocation of photosynthate (e.g., through disruption of hydrostatic pressure flow in phloem). As C reserves decline or become inaccessible, continued maintenance respiration has been hypothesized to lead to exhaustion of NSC after extended durations of drought, especially in isohydric plant species. On the other hand, hydraulic failure (e.g., catastrophic xylem embolisms) during drought may be the proximate cause of death, occurring before true C starvation occurs. Few studies have investigated specifically the mechanism(s) of tree death, and no published studies that we know of have quantified changes in NSC during mortality. EXPERIMENTAL DESIGN AND HYPOTHESES We conducted two studies that investigated whole-tree and tissue-specific C relations (photosynthetic C gain, respiration, dry-mass gain, and NSC pools) in Pinus flexilis seedlings during the initial establishment phase, which is characterized by progressive drought during summer. We measured survival, growth and biomass allocation, and C-balance physiology (photosynthetic C-gain and chlorophyll fluorescence, respiration C-use, and NSC concentrations) from germination to mortality. We hypothesized that 1) stomatal and biochemical limitations to C gain would constrain seedling survival (through inadequate seasonal C-balance), as has been shown for conifer seedlings near alpine treeline; 2) hydraulic constraints (embolisms and

  4. Light limitation and litter of an invasive clonal plant, Wedelia trilobata, inhibit its seedling recruitment

    Science.gov (United States)

    Qi, Shan-Shan; Dai, Zhi-Cong; Miao, Shi-Li; Zhai, De-Li; Si, Chun-Can; Huang, Ping; Wang, Rui-Ping; Du, Dao-Lin

    2014-01-01

    Background and Aims Invasive clonal plants have two reproduction patterns, namely sexual and vegetative propagation. However, seedling recruitment of invasive clonal plants can decline as the invasion process proceeds. For example, although the invasive clonal Wedelia trilobata (Asteraceae) produces numerous seeds, few seedlings emerge under its dense population canopy in the field. In this study it is hypothesized that light limitation and the presence of a thick layer of its own litter may be the primary factors causing the failure of seedling recruitment for this invasive weed in the field. Methods A field survey was conducted to determine the allocation of resources to sexual reproduction and seedling recruitment in W. trilobata. Seed germination was also determined in the field. Effects of light and W. trilobata leaf extracts on seed germination and seedling growth were tested in the laboratory. Key Results Wedelia trilobata blooms profusely and produces copious viable seeds in the field. However, seedlings of W. trilobata were not detected under mother ramets and few emerged seedlings were found in the bare ground near to populations. In laboratory experiments, low light significantly inhibited seed germination. Leaf extracts also decreased seed germination and inhibited seedling growth, and significant interactions were found between low light and leaf extracts on seed germination. However, seeds were found to germinate in an invaded field after removal of the W. trilobata plant canopy. Conclusions The results indicate that lack of light and the presence of its own litter might be two major factors responsible for the low numbers of W. trilobata seedlings found in the field. New populations will establish from seeds once the limiting factors are eliminated, and seeds can be the agents of long-distance dispersal; therefore, prevention of seed production remains an important component in controlling the spread of this invasive clonal plant. PMID:24825293

  5. Light limitation and litter of an invasive clonal plant, Wedelia trilobata, inhibit its seedling recruitment.

    Science.gov (United States)

    Qi, Shan-Shan; Dai, Zhi-Cong; Miao, Shi-Li; Zhai, De-Li; Si, Chun-Can; Huang, Ping; Wang, Rui-Ping; Du, Dao-Lin

    2014-08-01

    Invasive clonal plants have two reproduction patterns, namely sexual and vegetative propagation. However, seedling recruitment of invasive clonal plants can decline as the invasion process proceeds. For example, although the invasive clonal Wedelia trilobata (Asteraceae) produces numerous seeds, few seedlings emerge under its dense population canopy in the field. In this study it is hypothesized that light limitation and the presence of a thick layer of its own litter may be the primary factors causing the failure of seedling recruitment for this invasive weed in the field. A field survey was conducted to determine the allocation of resources to sexual reproduction and seedling recruitment in W. trilobata. Seed germination was also determined in the field. Effects of light and W. trilobata leaf extracts on seed germination and seedling growth were tested in the laboratory. Wedelia trilobata blooms profusely and produces copious viable seeds in the field. However, seedlings of W. trilobata were not detected under mother ramets and few emerged seedlings were found in the bare ground near to populations. In laboratory experiments, low light significantly inhibited seed germination. Leaf extracts also decreased seed germination and inhibited seedling growth, and significant interactions were found between low light and leaf extracts on seed germination. However, seeds were found to germinate in an invaded field after removal of the W. trilobata plant canopy. The results indicate that lack of light and the presence of its own litter might be two major factors responsible for the low numbers of W. trilobata seedlings found in the field. New populations will establish from seeds once the limiting factors are eliminated, and seeds can be the agents of long-distance dispersal; therefore, prevention of seed production remains an important component in controlling the spread of this invasive clonal plant. © The Author 2014. Published by Oxford University Press on behalf of

  6. Defoliation by pastoralists affects savanna tree seedling dynamics by limiting the facilitative role of canopy cover.

    Science.gov (United States)

    Bufford, Jennifer L; Gaoue, Orou G

    2015-07-01

    Recurrent tree defoliation by pastoralists, akin to herbivory, can negatively affect plant reproduction and population dynamics. However, our understanding of the indirect role of defoliation in seedling recruitment and tree-grass dynamics in tropical savanna is limited. In West African savanna, Fulani pastoralists frequently defoliate several fodder tree species to feed livestock in the dry season. We investigated the direct and indirect effects of recurrent defoliation of African mahogany (Khaya senegalensis) by Fulani people on seedling (forest systems in West Africa, it has the potential to affect tree-grass coexistence. Incorporating the influence of large tree defoliation into existing models of savanna dynamics can further our understanding of tree-grass coexistence and improve management. A rotating harvest system, which allows seedlings to recruit episodically, or a patchwork harvest, which maintains some nursery trees in the mosaic, could help sustain seedling recruitment and minimize the indirect effects of harvest.

  7. Nutrients limit photosynthesis in seedlings of a lowland tropical forest tree species.

    Science.gov (United States)

    Pasquini, S C; Santiago, L S

    2012-02-01

    We investigated how photosynthesis by understory seedlings of the lowland tropical tree species Alseis blackiana responded to 10 years of soil nutrient fertilization with N, P and K. We ask whether nutrients are limiting to light and CO(2) acquisition in a low light understory environment. We measured foliar nutrient concentrations of N, P and K, isotopic composition of carbon (δ(13)C) and nitrogen (δ(15)N), and light response curves of photosynthesis and chlorophyll fluorescence. Canopy openness was measured above each study seedling and included in statistical analyses to account for variation in light availability. Foliar N concentration increased by 20% with N addition. Foliar P concentration increased by 78% with P addition and decreased by 14% with N addition. Foliar K increased by 8% with K addition. Foliar δ(13)C showed no significant responses, and foliar δ(15)N decreased strongly with N addition, matching the low δ(15)N values of applied fertilizer. Canopy openness ranged from 0.01 to 6.71% with a mean of 1.76 ± 0.14 (± 1SE). Maximum photosynthetic CO(2) assimilation rate increased by 9% with N addition. Stomatal conductance increased with P addition and with P and K in combination. Chlorophyll fluorescence measurements revealed that quantum yield of photosystem II increased with K addition, maximum electron transport rate trended 9% greater with N addition (p = 0.07), and saturating photosynthetically active radiation increased with N addition. The results demonstrate that nutrient addition can enhance photosynthetic processes, even under low light availability.

  8. Stomatal and non-stomatal limitations on leaf carbon assimilation in beech (Fagus sylvatica L.) seedlings under natural conditions

    Energy Technology Data Exchange (ETDEWEB)

    Aranda, I.; Rodriguez-Calcerrada, J.; Robson, T. M.; Cano, F. J.; Alte, L.; Sanchez-Gomez, D.

    2012-07-01

    Limitations to diffusion and biochemical factors affecting leaf carbon uptake were analyzed in young beech seedlings (Fagus sylvtica L.) growing in natural gaps of a beech-wood at the southern limit of the species. Half of the seedlings received periodic watering in addition to natural rainfall to reduce the severity of the summer drought. Plant water status was evaluated by measuring predawn water potential. Basic biochemical parameters were inferred from chlorophyll fluorescence and photosynthesis-CO{sub 2} curves (A-C{sub c}) under saturating light. The curves were established on three dates during the summer months. The main variables studied included: stomatal and mesophyll conductance to CO{sub 2} (g{sub s} and g{sub m} respectively), maximum velocity of carboxylation (V{sub c}max) and maximum electron transport capacity (J{sub m}ax). The gm was estimated by two methodologies: the curve-fitting and J constant methods. Seedlings withstood moderate water stress, as the leaf predawn water potential ({Psi}{sub p}d) measured during the study was within the range -0.2 to -0.5 MPa. Mild drought caused gs and gm to decrease only slightly in response to {Psi}{sub p}d. However both diffusional parameters explained most of the limitations to CO{sub 2} uptake. In addition, it should be highlighted that biochemical limitations, prompted by V{sub c}max and J{sub m}ax, were related mainly to ontogenic factors, without any clear relationship with drought under the moderate water stress experienced by beech seedlings through the study. The results may help to further understanding of the functional mechanisms influencing the carbon fixation capacity of beech seedlings under natural conditions. (Author) 68 refs.

  9. Growth potential limits drought morphological plasticity in seedlings from six Eucalyptus provenances.

    Science.gov (United States)

    Maseda, Pablo H; Fernández, Roberto J

    2016-02-01

    Water stress modifies plant above- vs belowground biomass allocation, i.e., morphological plasticity. It is known that all species and genotypes reduce their growth rate in response to stress, but in the case of water stress it is unclear whether the magnitude of such reduction is linked to the genotype's growth potential, and whether the reduction can be largely attributed to morphological adjustments such as plant allocation and leaf and root anatomy. We subjected seedlings of six seed sources, three from each of Eucalyptus camaldulensis (potentially fast growing) and E. globulus (inherently slow growing), to three experimental water regimes. Biomass, leaf area and root length were measured in a 6-month glasshouse experiment. We then performed functional growth analysis of relative growth rate (RGR), and aboveground (leaf area ratio (LAR), specific leaf area (SLA) and leaf mass ratio (LMR)) and belowground (root length ratio (RLR), specific root length (SRL) and root mass ratio (RMR)) morphological components. Total biomass, root biomass and leaf area were reduced for all Eucalyptus provenances according to drought intensity. All populations exhibited drought plasticity, while those of greater growth potential (RGRmax) had a larger reduction in growth (discounting the effect of size). A positive correlation was observed between drought sensitivity and RGRmax. Aboveground, drought reduced LAR and LMR; under severe drought a negative correlation was found between LMR and RGRmax. Belowground, drought reduced SRL but increased RMR, resulting in no change in RLR. Under severe drought, a negative correlation was found between RLR, SRL and RGRmax. Our evidence strongly supports the classic ecophysiological trade-off between growth potential and drought tolerance for woody seedlings. It also suggests that slow growers would have a low capacity to adjust their morphology. For shoots, this constraint on plasticity was best observed in partition (i.e., LMR) whereas for

  10. Limits to seaward expansion of mangroves: Translating physical disturbance mechanisms into seedling survival gradients

    NARCIS (Netherlands)

    Balke, T.; Swales, A.; Lovelock, C.E.; Herman, P.M.J.; Bouma, T.J.

    2015-01-01

    Mangroves are valuable coastal habitats that are globally under pressure due to climate change and coastal development. Small-scale physical disturbance by tidal inundation and wave-induced sediment dynamics has been described as the main bottlenecks to mangrove seedling establishment on exposed tid

  11. Effects of forest fragmentation on the seedling recruitment of a tropical herb: assessing seed vs. safe-site limitation.

    Science.gov (United States)

    Uriarte, María; Bruna, Emilio M; Rubim, Paulo; Anciães, Marina; Jonckheere, Inge

    2010-05-01

    Studies simultaneously evaluating the importance of safe-site and seed limitation for plant establishment are rare, particularly in human-modified landscapes. We used spatially explicit neighborhood models together with data from 10 0.5-ha mapped census plots in a fragmented landscape spanning 1000 km2 to (1) evaluate the relative importance of seed production, dispersal, and safe-site limitation for the recruitment of the understory herb Heliconia acuminata; and (2) determine how these processes differ between fragments and continuous forests. Our analyses demonstrated a large degree of variation in seed production, dispersal, and establishment among and within the 10 study plots. Seed production limitation was strong but only at small spatial scales. Average dispersal distance was less than 4 m, leading to severe dispersal limitation at most sites. Overall, safe-site limitation was the most important constraint on seedling establishment. Fragmentation led to a more heterogeneous light environment with negative consequences for seedling establishment but had little effect on seed production or dispersal. These results suggest that the effects of fragmentation on abiotic processes may be more important than the disruption of biotic interactions in driving biodiversity loss in tropical forests, at least for some functional groups. These effects may be common when the matrix surrounding fragments contains enough tree cover to enable movement of dispersers and pollinators.

  12. Low Root Zone Temperature Limits Nutrient Effects on Cucumber Seedling Growth and Induces Adversity Physiological Response

    Institute of Scientific and Technical Information of China (English)

    YAN Qiu-yan; DUAN Zeng-qiang; MAO Jing-dong; LI Xun; DONG Fei

    2013-01-01

    Effects of root-zone temperatures (RZT) (12°C-RZT and 20°C-RZT) and different N, P, and K nutrient regimes on the growth, reactive oxygen species (ROS), and antioxidant enzyme in cucumber seedlings were investigated in hydroponics. Strong interactions were observed between RZT and nutrient on the dry weight (P=0.001), root length (P=0.001) and leaf area (P=0.05). Plant dry weights were suppressed at low RZT of 12°C, while higher biomass and growth of cucumber seedlings were produced at elevated RZT of 20°C under each nutrient treatment. Growth indexes (plant height, internode length, root length, and leaf area) at 12°C-RZT had less difference among nutrient treatments, but greater response was obtained for different nutrients at high RZT. RZT had larger effects (P=0.001) on cucumber seedling growth than nutrients. In addition, N was more effective nutrients to plant growth than P and K under low root temperature to plant growth. Higher hydrogen peroxide (H2O2), malondialdehyde (MDA), soluble sugar (SS) contents in leaves were observed at 12°C-RZT in all nutrient treatments than those at 20°C-RZT, indicating the chilling adversity damaged to plant growth. In general, antioxidant enzyme had larger response under low root-zone temperature. Superoxide dismutase (SOD) activities were higher in both leaves and roots while peroxidase (POD) and catalase (CAT) showed large different action in leaves and roots at both the two root-zone temperature.

  13. The limitations of seedling growth and drought tolerance to novel soil substrates in arid systems: Implications for restoration success

    Science.gov (United States)

    Bateman, Amber; Lewandrowski, Wolfgang; Stevens, Jason; Muñoz-Rojas, Miriam

    2016-04-01

    Introduction With the limited knowledge available regarding the impact of drought on seedling growth, an understanding of seedling tolerance to arid conditions is crucial for restoration success (James et al., 2013; Muñoz-Rojas et al., 2014). However, restoration in semi-arid areas faces the challenge of re-establishing plant communities on altered soil substrates (Muñoz-Rojas et al., 2015). These substrates are a result of anthropogenic disturbances such as mining which have altered the plant-soil-water dynamics of the ecosystem (Machado et al., 2013). The aim of this study was to assess the impact of mining on the plant-soil-water dynamics of an arid ecosystem of Western Australia (Pilbara region, North Western Australia) and the implications these altered relationships have on seedling growth and their responses to drought. Methods Drought responses of native plant species were assessed through a series of glasshouse experiments. Firstly, 21 species dominant to the Pilbara region were subjected to drought in a topsoil growth media to assess variation in responses (leaf water potential at the time of stomatal closure) across species and identify traits associated with drought tolerance. Secondly, four species ranging in their drought tolerance identified previously, were grown to two leaf stages (second and fourth leaf stage) in three mining substrates (topsoil, a topsoil and waste mix and waste) to assess seedling drought responses to various potential restoration substrates and how that varied with plant development stage. Results and discussion Four morphological traits were found to be significantly associated with drought indicators (leaf mass ratio, stem area, stem length, stem weight), however, these were weak correlations. Waste substrate and its addition to topsoil reduced plant total biomass but did not alter species responses to drought. However, the soil physical properties of the waste reduced water retention and water availability for plant uptake

  14. What loggers leave behind: Impacts on big-leaf mahogany (Swietenia macrophylla) commercial populations and potential for post-logging recovery in the Brazilian Amazon.

    Science.gov (United States)

    James Grogan; Stephen B. Jennings; R. Matthew Landis; Mark Schulze; Anadilza M.V. Baima; do Carmo A. Lopes J.; Julian M. Norghauer; L. Rog& eacute Oliveira; rio; Frank Pantoja; Diane Pinto; Jose Natalino M. Silva; Edson Vidal; Barbara L. Zimmerman

    2008-01-01

    The sustainability of current harvest practices for high-value Meliaceae can be assessed by quantifying logging intensity and projecting growth and survival by post-logging populations over anticipated intervals between harvests. From 100%-area inventories of big-leaf mahogany (Swietenia macrophylla) covering 204 ha or more at eight logged and unlogged forest sites...

  15. Leaf Collection Posting Log

    Data.gov (United States)

    Montgomery County of Maryland — This dataset contains leaf collection dates for area and subarea where leaf collection service is provided by Montgomery County Department of Transportation. Update...

  16. Quantifying efficacy and limits of unmanned aerial vehicle (UAV) technology for weed seedling detection as affected by sensor resolution.

    Science.gov (United States)

    Peña, José M; Torres-Sánchez, Jorge; Serrano-Pérez, Angélica; de Castro, Ana I; López-Granados, Francisca

    2015-03-06

    In order to optimize the application of herbicides in weed-crop systems, accurate and timely weed maps of the crop-field are required. In this context, this investigation quantified the efficacy and limitations of remote images collected with an unmanned aerial vehicle (UAV) for early detection of weed seedlings. The ability to discriminate weeds was significantly affected by the imagery spectral (type of camera), spatial (flight altitude) and temporal (the date of the study) resolutions. The colour-infrared images captured at 40 m and 50 days after sowing (date 2), when plants had 5-6 true leaves, had the highest weed detection accuracy (up to 91%). At this flight altitude, the images captured before date 2 had slightly better results than the images captured later. However, this trend changed in the visible-light images captured at 60 m and higher, which had notably better results on date 3 (57 days after sowing) because of the larger size of the weed plants. Our results showed the requirements on spectral and spatial resolutions needed to generate a suitable weed map early in the growing season, as well as the best moment for the UAV image acquisition, with the ultimate objective of applying site-specific weed management operations.

  17. Quantifying Efficacy and Limits of Unmanned Aerial Vehicle (UAV Technology for Weed Seedling Detection as Affected by Sensor Resolution

    Directory of Open Access Journals (Sweden)

    José M. Peña

    2015-03-01

    Full Text Available In order to optimize the application of herbicides in weed-crop systems, accurate and timely weed maps of the crop-field are required. In this context, this investigation quantified the efficacy and limitations of remote images collected with an unmanned aerial vehicle (UAV for early detection of weed seedlings. The ability to discriminate weeds was significantly affected by the imagery spectral (type of camera, spatial (flight altitude and temporal (the date of the study resolutions. The colour-infrared images captured at 40 m and 50 days after sowing (date 2, when plants had 5–6 true leaves, had the highest weed detection accuracy (up to 91%. At this flight altitude, the images captured before date 2 had slightly better results than the images captured later. However, this trend changed in the visible-light images captured at 60 m and higher, which had notably better results on date 3 (57 days after sowing because of the larger size of the weed plants. Our results showed the requirements on spectral and spatial resolutions needed to generate a suitable weed map early in the growing season, as well as the best moment for the UAV image acquisition, with the ultimate objective of applying site-specific weed management operations.

  18. EFFECT OF POST-LOGGING SILVICULTURAL TREATMENT ON GROWTH RATES OF RESIDUAL STAND IN A TROPICAL FOREST

    Directory of Open Access Journals (Sweden)

    Haruni Krisnawati

    2010-12-01

    Full Text Available Post-logging silvicultural treatments are generally performed to improve yields of the remaining tree species by increasing their growth rate. In this study the effects of silvicultural treatment on the growth rates of commercial (dipterocarps and non-dipterocarps as well as non- commercial tree species in a tropical forest in West Kalimantan were examined and were compared to a control treatment. Silvicultural treatment applied was liberation of future crop trees from lianas and neighbouring competing trees. Treatments were applied to six plots of 80 m x 80 m each. The plots comprised 64 quadrats of 10 m x 10 m to allow better control of measurements. The treatment and control plots were established 6 years after logging. Effects were measured 2,4 and 7 years after treatment application. In all obser vation periods, the growth rates increased with silvicultural treatment. Overall, commercial dipterocarps, commercial non-dipterocarps and non-commercial tree species groups differed in response to silvicultural treatment. The growth rates of commercial tree species in plots that received silvicultural treatment were 62–97% higher than in the control plots. For non-commercial tree species, the increase of growth rates was 20–58%, compared to the control plots. These results indicate that the application of silvicultural treatments after logging could help improve the growth of the residual stands. These provide quantitative information that silvicultural treatments in logged-over forest should be considered as a viable management option and may guide the choice of cutting cycle.

  19. Limitações nutricionais de mudas de mangostãozeiro Nutritional limitations of mangosteen seedlings

    Directory of Open Access Journals (Sweden)

    Larissa Alexandra Cardoso Moraes

    2006-07-01

    Full Text Available Este trabalho teve o objetivo de avaliar, por meio da análise foliar, as limitações nutricionais para produção de mudas de mangostãozeiro. Após 12 meses do plantio, em condições de viveiro, com sombreamento no início do desenvolvimento, foi observado amarelecimento progressivo das folhas novas, com diminuição significativa dos teores foliares de Fe e Mn. A aplicação de sulfato de manganês (0,8 mg L-1 de Mn + 2,5 g L-1 de uréia, via foliar, não ocasionou recuperação da tonalidade verde do limbo foliar. Entretanto, com sulfato de ferro, na concentração de 0,8 mg L-1 de Fe + 2,5 g L-1 de uréia, houve aumento da pigmentação verde nas folhas, o que mostra a baixa eficiência do mangostãozeiro na absorção de Fe, apesar da alta concentração desse nutriente no terriço (223,7 mg dm-3. Isto indica a necessidade de aplicação suplementar de Fe, no substrato ou nas folhas, na fase de viveiro do mangostãozeiro.This work had the objective to evaluate, by foliar analysis, the nutritional limitations to the production of mangosteen seedlings. After 12 months in the nursery, under shade in the initial development, a progressive yellowing of the young leaves was observed, together with significant reduction of Fe and Mn concentrations in the leaf. Foliar sprays of Mn 0.8 mg L-1 as MnSO4 plus 2.5 g L-1 of urea was ineffective to recover green color of the leaf blades. However, this was achieved with application of Fe 0.8 mg L-1, as FeSO4, plus 2.5 g L-1 of urea, with increase of regreening, which highlights the low Fe absorption efficiency of mangosteen, despite the high concentration of this nutrient in the substrate of surface soil (223.7 mg dm-3. This indicates the need of application of Fe in the substrate or on the leaves, during the nursery stage of mangosteen.

  20. Effects of high CO2 on growth and metabolism of Arabidopsis seedlings during growth with a constantly limited supply of nitrogen.

    Science.gov (United States)

    Takatani, Nobuyuki; Ito, Takuro; Kiba, Takatoshi; Mori, Marie; Miyamoto, Tetsuro; Maeda, Shin-Ichi; Omata, Tatsuo

    2014-02-01

    Elevated CO2 has been reported to stimulate plant growth under nitrogen-sufficient conditions, but the effects of CO2 on growth in a constantly nitrogen-limited state, which is relevant to most natural habitats of plants, remain unclear. Here, we maintained Arabidopsis seedlings under such conditions by growing a mutant with reduced nitrate uptake activity on a medium containing nitrate as the sole nitrogen source. Under nitrogen-sufficient conditions (i.e. in the presence of ammonium), growth of shoots and roots of both the wild type (WT) and the mutant was increased approximately 2-fold by elevated CO2. Growth stimulation of shoots and roots by elevated CO2 was observed in the WT growing with nitrate as the sole nitrogen source, but in the mutant grown with nitrate, the high-CO2 conditions stimulated only the growth of roots. In the mutant, elevated CO2 caused well-known symptoms of nitrogen-starved plants, including decreased shoot/root ratio, reduced nitrate content and accumulation of anthocyanin, but also had an increased Chl content in the shoot, which was contradictory to the known effect of nitrogen depletion. A high-CO2-responsive change specific to the mutant was not observed in the levels of the major metabolites, although CO2 responses were observed in the WT and the mutant. These results indicated that elevated CO2 causes nitrogen limitation in the seedlings grown with a constantly limited supply of nitrogen, but the Chl content and the root biomass of the plant increase to enhance the activities of both photosynthesis and nitrogen uptake, while maintaining normal metabolism and response to high CO2.

  1. Seedling mycorrhiza

    DEFF Research Database (Denmark)

    Rasmussen, Hanne Nina; Rasmussen, Finn N.

    2014-01-01

    mycobionts suggest a derivation from a pathogenic relationship, and sister group comparison offers little support for derivation from other mycorrhizal relationships. A combination of in situ sowings and molecular identification of seedling mycobionts has established that a broad range of fungi besides...

  2. Limiter

    Science.gov (United States)

    Cohen, S.A.; Hosea, J.C.; Timberlake, J.R.

    1984-10-19

    A limiter with a specially contoured front face is provided. The front face of the limiter (the plasma-side face) is flat with a central indentation. In addition, the limiter shape is cylindrically symmetric so that the limiter can be rotated for greater heat distribution. This limiter shape accommodates the various power scrape-off distances lambda p, which depend on the parallel velocity, V/sub parallel/, of the impacting particles.

  3. Windows of opportunity: tresholds to mangrove seedling establishement on tidal flats

    NARCIS (Netherlands)

    Balke, T.; Bouma, T.J.; Horstman, Erik; Webb, E.L.; Erftemeijer, P.L.A.; Herman, P.M.J.

    2011-01-01

    Physical processes limiting colonization of bare tidal flats by pioneer mangrove species have commonly been described but not yet quantified. Understanding thresholds to early seedling establishment is critical for successful restoration and management of mangrove forests. We determined how seedling

  4. Windows of opportunity: thresholds to mangrove seedling establishment on tidal flats

    NARCIS (Netherlands)

    Balke, T.; Bouma, T.J.; Horstman, E.M.; Webb, E.L.; Erftemeijer, P.L.A.; Herman, P.M.J.

    2011-01-01

    Physical processes limiting colonization of bare tidal flats by pioneer mangrove species have commonly been described but not yet quantified. Understanding thresholds to early seedling establishment is critical for successful restoration and management of mangrove forests. We determined how seedling

  5. The Study of Seedlings

    NARCIS (Netherlands)

    Jacobs, M.

    1966-01-01

    ”The seedling represents the most critical stage in the life of a tree. Conditions of seeding and germination may be entirely favourable, and natural seedlings may appear in countless quantities at the beginning of the rainy season, only to disappear largely or entirely within a comparatively short

  6. Responsibility of non-stomatal limitations for the reduction of photosynthesis-response of photosynthesis and antioxidant enzyme characteristics in alfalfa (Medicago sativa L.) seedlings to water stress and rehydration

    Institute of Scientific and Technical Information of China (English)

    LI Wenrao; ZHANG Suiqi; SHAN Lun

    2007-01-01

    Water stress by polyethylene glycol (PEG)-6000 solution (Ψs=0.2 MPa,stress time:48 h,rehydration time:48 h) was performed in leaves of two alfalfa cultivar (Long-Dong and Algonquin) seedlings.Gas exchange parameters,chlorophyll fluorescence parameters,activity of antioxidant enzyme and photosynthetic pigment concentrations were measured to investigate the available photosynthetic and antioxidant enzyme response to variable water conditions as well as stomatal and non-stomatal limitations to photosynthesis.The results showed that non-stomatal limitations were responsible for the reduction of photosynthesis during water stress.At the beginning of water stress (12 h),water was lost and then the stomata closed rapidly,which resulted in a decrease of transpiration,net photosynthesis and CO2 diffusion.Therefore,when intercellular CO2 concentration and carboxylation efficiency decrease,water use efficiency and value of stomatal limitation would increase.However,the decline of net photosynthetic rate was faster than transpiration rate.At the same time,the maximal photochemical efficiency,potential activity of PSII reaction center and photochemical quenching of chlorophyll fluorescence declined significantly,the activity of antioxidant enzyme increased rapidly and the photosynthetic pigment concentrations changed slightly.The results also indicated that,at the initial period of stress,neither oxidative stress nor membrane lipid peroxidation was induced,nor were photosynthetic structures damaged,but photosynthetic functions were partly inhibited.Therefore,the stomatal limitation and non-stomatal limitations had the same responsibility for the reduction of photosynthesis.At the mid-late stage of water stress,net photosynthetic rate,stomatal conductance,maximal photochemical efficiency,potential activity of PSII reaction center and photochemical quenching of chlorophyll fluorescence decreased linearly with the decline of the relative water content.And the relative electron

  7. Influence of irrigation method and container type on Northern red oak seedling growth and media electrical conductivity

    Science.gov (United States)

    Anthony S. Davis; Douglass F. Jacobs; Ronald P. Overton; R. Kasten Dumroese

    2008-01-01

    Container production of hardwood seedlings has not been extensively practiced. Efficient nursery production of hardwood seedlings in containers can be limited by formation of a broad foliar canopy, which limits irrigation uniformity. This study was established to investigate suitability of subirrigation, a method of irrigating seedlings from the container base that...

  8. Eucalyptus obliqua seedling growth in organic vs. mineral soil horizons.

    Science.gov (United States)

    Barry, Karen M; Janos, David P; Nichols, Scott; Bowman, David M J S

    2015-01-01

    Eucalyptus obliqua, the most widespread timber tree in Tasmania, is a pioneer after fire which can eliminate the organic layer of forest soil, exposing the underlying mineral soil. We compared seedling growth, mycorrhiza formation, and mineral nutrient limitation in organic layer vs. mineral soil. We grew E. obliqua seedlings separately in pots of organic layer and mineral soil in a glasshouse. Additional treatments of organic soil only, involved fully crossed methyl-bromide fumigation and fertilization. Fertilization comprised chelated iron for 121 days after transplant (DAT) followed by soluble phosphorus. At 357 DAT, whole plant dry weight was three times greater in ambient organic than in mineral soil. In organic soil, fumigation halved ectomycorrhiza abundance and reduced seedling growth at 149 DAT, but by 357 DAT when negative effects of fumigation on seedling growth had disappeared, neither fumigation nor fertilization affected mycorrhiza abundance. Iron fertilization diminished seedling growth, but subsequent phosphorus fertilization improved it. E. obliqua seedlings grow much better in organic layer soil than in mineral soil, although phosphorus remains limiting. The prevalent forestry practice of burning to mineral soil after timber harvest exposes a poor growth medium likely only partially compensated by fire-induced mineral soil alterations.

  9. Eucalyptus obliqua seedling growth in organic versus mineral soil horizons

    Directory of Open Access Journals (Sweden)

    Karen eBarry

    2015-02-01

    Full Text Available Eucalyptus obliqua, the most widespread timber tree in Tasmania, is a pioneer after fire which can eliminate the organic layer of forest soil, exposing the underlying mineral soil. We compared seedling growth, mycorrhiza formation, and mineral nutrient limitation in organic layer versus mineral soil. We grew E. obliqua seedlings separately in pots of organic layer and mineral soil in a glasshouse. Additional treatments of organic soil only, involved fully crossed methyl-bromide fumigation and fertilization. Fertilization comprised chelated iron for 121 days after transplant (DAT followed by soluble phosphorus. At 357 DAT, whole plant dry weight was three times greater in ambient organic than in mineral soil. In organic soil, fumigation halved ectomycorrhiza abundance and reduced seedling growth at 149 DAT, but by 357 DAT when negative effects of fumigation on seedling growth had disappeared, neither fumigation nor fertilization affected mycorrhiza abundance. Iron fertilization diminished seedling growth, but subsequent phosphorus fertilization improved it. E. obliqua seedlings grow much better in organic layer soil than in mineral soil, although phosphorus remains limiting. The prevalent forestry practice of burning to mineral soil after timber harvest exposes a poor growth medium likely only partially compensated by fire-induced mineral soil alterations.

  10. Community-Wide Spatial and Temporal Discordances of Seed-Seedling Shadows in a Tropical Rainforest

    Science.gov (United States)

    Rother, Débora Cristina; Pizo, Marco Aurélio; Siqueira, Tadeu; Rodrigues, Ricardo Ribeiro; Jordano, Pedro

    2015-01-01

    Several factors decrease plant survival throughout their lifecycles. Among them, seed dispersal limitation may play a major role by resulting in highly aggregated (contagious) seed and seedling distributions entailing increased mortality. The arrival of seeds, furthermore, may not match suitable environments for seed survival and, consequently, for seedling establishment. In this study, we investigated spatio-temporal patterns of seed and seedling distribution in contrasting microhabitats (bamboo and non-bamboo stands) from the Brazilian Atlantic Forest. Spatial distribution patterns, spatial concordance between seed rain and seedling recruitment between subsequent years in two fruiting seasons (2004–2005 and 2007–2009), and the relation between seeds and seedlings with environmental factors were examined within a spatially-explicit framework. Density and species richness of both seeds and seedlings were randomly distributed in non-bamboo stands, but showed significant clustering in bamboo stands. Seed and seedling distributions showed across-year inconsistency, suggesting a marked spatial decoupling of the seed and seedling stages. Generalized linear mixed effects models indicated that only seed density and seed species richness differed between stand types while accounting for variation in soil characteristics. Our analyses provide evidence of marked recruitment limitation as a result of the interplay between biotic and abiotic factors. Because bamboo stands promote heterogeneity in the forest, they are important components of the landscape. However, at high densities, bamboos may limit recruitment for the plant community by imposing marked discordances of seed arrival and early seedling recruitment. PMID:25856393

  11. RESULTS ON THE EFFECT OF DIFFERENT TYPES OF ROMANIAN NATIVE PEAT BIO COMPOSITES POTS ON SEEDLING GROWTH

    Directory of Open Access Journals (Sweden)

    Florina Uleanu

    2013-07-01

    Full Text Available Seedlings production is an important link in vegetable culture because many vegetables species are grown by producing prior of seedlings. The theme work is in line with Western trends to produce seedlings by integrating new vegetables technologies, profitable, with positive effect on limiting pathogens to obtain seedlings, using biodegradable pots. Were conducted various observations and measurements on plants when they have reached the optimum phase for planting. We have determined: height of seedlings, root length, leaf number, root volume total weight, weight of the aerial and weight of roots. The obtained data was calculated and considered as average / variant.

  12. The role of plant water relations in achieving and maintaining the target seedling

    Science.gov (United States)

    John G. Mexal; Nabil Khadduri

    2011-01-01

    Water management is one of the most important factors in achieving the target seedling. Water is required for cell growth, nutrient transport, cooling through transpiration, and in small amounts for the photosynthetic reaction. Furthermore, judicious use of limiting water availability during the hardening phase can induce budset and increase seedling cold hardiness....

  13. Linking carbon and water relations to drought-induced mortality in Pinus flexilis seedlings.

    Science.gov (United States)

    Reinhardt, Keith; Germino, Matthew J; Kueppers, Lara M; Domec, Jean-Christophe; Mitton, Jeffry

    2015-07-01

    Survival of tree seedlings at high elevations has been shown to be limited by thermal constraints on carbon balance, but it is unknown if carbon relations also limit seedling survival at lower elevations, where water relations may be more important. We measured and modeled carbon fluxes and water relations in first-year Pinus flexilis seedlings in garden plots just beyond the warm edge of their natural range, and compared these with dry-mass gain and survival across two summers. We hypothesized that mortality in these seedlings would be associated with declines in water relations, more so than with carbon-balance limitations. Rather than gradual declines in survivorship across growing seasons, we observed sharp, large-scale mortality episodes that occurred once volumetric soil-moisture content dropped below 10%. By this point, seedling water potentials had decreased below -5 MPa, seedling hydraulic conductivity had decreased by 90% and seedling hydraulic resistance had increased by >900%. Additionally, non-structural carbohydrates accumulated in aboveground tissues at the end of both summers, suggesting impairments in phloem-transport from needles to roots. This resulted in low carbohydrate concentrations in roots, which likely impaired root growth and water uptake at the time of critically low soil moisture. While photosynthesis and respiration on a leaf area basis remained high until critical hydraulic thresholds were exceeded, modeled seedling gross primary productivity declined steadily throughout the summers. At the time of mortality, modeled productivity was insufficient to support seedling biomass-gain rates, metabolism and secondary costs. Thus the large-scale mortality events that we observed near the end of each summer were most directly linked with acute, episodic declines in plant hydraulic function that were linked with important changes in whole-seedling carbon relations.

  14. Potential production of Aspidosperma cylindrocarpon seedlings viarescue seedlings

    Directory of Open Access Journals (Sweden)

    Nathália Ferreira e Silva

    Full Text Available ABSTRACT: Translocation of rare populations is regarded as the last resort for the conservation of species whose habitat destruction is imminent. The objective of the present study was to evaluate the effect of two height classes and three leaf reduction intensities on growth and increases in height, stem diameter, survival, and new leaf production in seedlings of Aspidosperma cylindrocarpon (peroba obtained via rescue seedlings in a remnant of tropical semi deciduous forest. We recovered 240 individuals that were divided into two height classes (Class I-5 to 15cm and Class II-20 to 35cm and subjected to three leaf reduction intensities (0%, 50%, and 100%, which were then transported to a shade house with 50% light reduction. Measurements of height, stem diameter, and new leaf production were collected 8 times at 0, 15, 60, 75, 90, 105, 120, and 135 days, and survival rate was measured at day 135. The average survival rate was 82.9%; 77.5% for one Class I (5-15cm and 88.3% for Class II (20-35cm. Higher seedling growth was observed for the 0% leaf reduction treatment in both height classes. The leaves insertion were greater in the 100% cuts, with a decrease observed over time. It is advisable to restore A. cylindrocarpon seedlings in two height classes owing to the high survival rate, leaf appearance, and growth reported in the present study. The no-leaf reduction treatment (0% is the most viable alternative for the production of A. cylindrocarpon seedlings, via rescue seedlings.

  15. Development of seedlings of watermelon cv. Crimson Sweet irrigated with biosaline water

    Directory of Open Access Journals (Sweden)

    José E. S. B. da Silva

    2015-09-01

    Full Text Available ABSTRACTThe limited access and the scarcity of good quality water for agriculture are some of the major problems faced in agricultural areas, particularly in arid and semiarid regions. The aim of this study was to evaluate the quality of watermelon seedlings (cv. Crimson Sweet, irrigated with different concentrations of biosaline water of fish culture. The experimental design was completely randomized with five treatments, corresponding to biosaline water at different concentrations (0, 33, 50, 67 and 100%, and four replicates of 108 seedlings. Watermelon seeds were sown in plastic trays filled with commercial substrate and irrigated with different solutions of biosaline water. Seedlings were harvested for biometric analysis at 14, 21 and 28 days after sowing. The use of biosaline water did not affect emergence and establishment of seedlings until 14 days after sowing, the period recommended for transplantation. However, the use of biosaline water affected the development of seedlings with longer exposure time.

  16. Experimental test for facilitation of seedling recruitment by the dominant bunchgrass in a fire-maintained savanna.

    Directory of Open Access Journals (Sweden)

    Gwenllian D Iacona

    Full Text Available Facilitative interactions between neighboring plants can influence community composition, especially in locations where environmental stress is a factor limiting competitive effects. The longleaf pine savanna of the southeastern United States is a threatened and diverse system where seedling recruitment success and understory species richness levels are regulated by the availability of moist microsites. We hypothesized that the dominant bunch grass species (Aristida stricta Michx. would facilitate moist seedling microsites through shading, but that the effect would depend on stress gradients. Here, we examined the environmental properties modified by the presence of wiregrass and tested the importance of increased shade as a potential facilitative mechanism promoting seedling recruitment across spatial and temporal stress gradients. We showed that environmental gradients, season, and experimental water manipulation influence seedling success. Environmental properties were modified by wiregrass proximity in a manner that could facilitate seedling success, but we showed that shade alone does not provide a facilitative benefit to seedlings in this system.

  17. N2-fixation and seedling growth promotion of lodgepole pine by endophytic Paenibacillus polymyxa.

    Science.gov (United States)

    Anand, Richa; Grayston, Susan; Chanway, Christopher

    2013-08-01

    We inoculated lodgepole pine (Pinus contorta var. latifolia (Dougl.) Engelm.) with Paenibacillus polymyxa P2b-2R, a diazotrophic bacterium previously isolated from internal stem tissue of a naturally regenerating pine seedling to evaluate biological nitrogen fixation and seedling growth promotion by this microorganism. Seedlings generated from pine seed inoculated with strain P2b-2R were grown for up to 13 months in a N-limited soil mix containing 0.7 mM available N labeled as Ca((15)NO3)2 to facilitate detection of N2-fixation. Strain P2b-2R developed a persistent endophytic population comprising 10(2)-10(6) cfu g(-1) plant tissue inside pine roots, stems, and needles during the experiment. At the end of the growth period, P2b-2R had reduced seedling mortality by 14 % and (15)N foliar N abundance 79 % and doubled foliar N concentration and seedling biomass compared to controls. Our results suggest that N2-fixation by P. polymyxa enhanced growth of pine seedlings and support the hypothesis that plant-associated diazotrophs capable of endophytic colonization can satisfy a significant proportion of the N required by tree seedlings growing under N-limited conditions.

  18. 增强UV-B辐射和Cd2+复合胁迫下绿豆幼苗Cd积累和光合作用的气孔和非气孔限制%Stomatal and Nonstomatal Limitations of Photosynthesis in P. radiatus L. Seedling Leaves under the Combination of Enhanced UVB Radiation and Cd2+ Stress

    Institute of Scientific and Technical Information of China (English)

    张媛华; 王真; 佘小平

    2011-01-01

    [ Objective ] The research aimed to study the stomatal and nonstomatal limitations of photosynthesis in P. radiatus L. seedling leaves under the combination of enhanced UV-B radiation and Cd2+ stress. [ Method] The test designed one control group and 3 test groups, enhanced UV-B radiation(UV-B) group, Cd2+ (Cd) group and enhanced UV-B radiation + Cd2+ (UV-B + Cd) group respectively. Stomatl and nonstomatal limitations of photosynthesis in P. radiatus L. seedling leaves under the combination of 0.35 W/m2 UV-B radiation and 1 μmol/L Cd2+ stress were studied. Cd concentration in root, hypocotyls, and leaf were determined by atomic absorption spectrometer, respectively. The photnsynthetic parameters of the first pair leaves of P. radiatus L. seeding were monitored by TPS-1 photosynthesis system or calculated according to the theory of Farquhar and Sharkey. [Result] Cd concentration allocated in different parts of P. radiatus L. was root > hypocotyl > leaf,and UV-B group had no effect on the absorption and allocation in P. radiatus L.. In addition, separated or combined treatments of enhanced UV-B radiation and Cd2 + stress all resulted in a decrease in net photosynthetic rate, stomatal conductance, photosynthetic ability, efficiency of CO2 carboxylafion and rubisco content. That intercellular CO2 concentration increased and stomatal limitation value decreased under UV-B treatment indicated that the inhibition of photosynthesis in P. radiatus L. seedling leaves was nonstomatal limitation. That intercellular CO2 concentration decreased and stomatal limitation value increased under Cd treatment and combined treatment showed that the inhibition of photosynthesis in Cd treatment was stomatal limitation and the combined treatment was the results of stomatal and nonstomatal limination. [ Conclusion ] The study reveals the main factors of photosynthetic changes of P. radiatus L. seedling under the combination of enhanced UV-B radiation and Cd2+ stress, can provide the

  19. Measuring Maize Seedling Drought Response in Search of Tolerant Germplasm

    Directory of Open Access Journals (Sweden)

    Dirk Hays

    2013-02-01

    Full Text Available To identify and develop drought tolerant maize (Zea mays L., high-throughput and cost-effective screening methods are needed. In dicot crops, measuring survival and recovery of seedlings has been successful in predicting drought tolerance but has not been reported in C4 grasses such as maize. Seedlings of sixty-two diverse maize inbred lines and their hybrid testcross progeny were evaluated for germination, survival and recovery after a series of drought cycles. Genotypic differences among inbred lines and hybrid testcrosses were best explained approximately 13 and 18 days after planting, respectively. Genotypic effects were significant and explained over 6% of experimental variance. Specifically three inbred lines had significant survival, and 14 hybrids had significant recovery. However, no significant correlation was observed between hybrids and inbreds (R2 = 0.03, indicating seedling stress response is more useful as a secondary screening parameter in hybrids than in inbred lines per se. Field yield data under full and limited irrigation indicated that seedling drought mechanisms were independent of drought responses at flowering in this study.

  20. Studies With Triazoles to Alleviate Drought Stress in GreenHouse-Grown Maize (Zea mays) Seedlings

    OpenAIRE

    Batlang, Utlwang

    2006-01-01

    In semi-arid environments, dry-land farming often exposes crops to drought stress. Although some plant species are well adapted to drought, most crops are not. Drought can reduce plant populations and limit growth and development in ways that have serious yield consequences. Planting at the beginning of the wet season, when rainfalls are often sporadic and unreliable, can expose young maize seedlings to severe drought. Through the use of plant growth regulators (PGR), maize seedlings can per...

  1. Response of barley seedlings to oxidative stress generated by treatments with growth hormones

    OpenAIRE

    Zenovia Olteanu; Elena Truta; Lacramiora Oprica; Maria Magdalena Zamfirache

    2009-01-01

    The effects induced by growth hormone regulators on soluble protein level and some oxidoreductases in Hordeum vulgare cv. Madalin seedlings were investigated. The study of superoxide dismutase, catalyse and peroxidase behaviour and of protein synthesis was realized in dynamics to evaluate the response of barley seedlings to oxidative stress generated by exposure to hormone factors. During experiments, peroxidase registered smaller limits of variability than superoxide dismutase an...

  2. Substrate influences ecophysiological performance of tree seedlings.

    Science.gov (United States)

    Pröll, Gisela; Hietz, Peter; Delaney, Christina M; Katzensteiner, Klaus

    2016-01-01

    Unfavourable soil conditions frequently limit tree regeneration in mountain forests on calcareous bedrock. Rocky, shallow organic soils on dolomite pose a particular problem for tree regeneration due to commonly restricted water and nutrient supplies. Moreover, an often dense layer of understorey vegetation competes for the limited resources available. Hence, an array of interacting factors impairs tree seedlings' performance on dolomite, but there is little information on the ecophysiological mechanisms. We studied the effects of substrate, competing vegetation and foliar nutrient concentrations on the photosynthetic rate (A), stomatal conductance (gs) and leaf water potentials (ψ) of sycamore (Acer pseudoplatanus L.), beech (Fagus sylvatica L.), spruce [Picea abies (L.) Karst.] and larch (Larix decidua Mill.) under controlled (well-watered/drought-stressed) conditions and under prevailing field conditions. While A and gs of well-watered spruce in the pot experiment were reduced by the mineral substrate, the organic dolomite substrate with dense competing vegetation reduced gs and ψ of sycamore, spruce and larch under drought-stressed conditions in the field. For sycamore and spruce, A and gs were strongly correlated with foliar nitrogen (N) and potassium (K) concentrations in the pot experiment. In contrast, soil water primarily affected beech and larch. Finally, dense competing vegetation negatively affected A and gs of spruce and A of larch on dolomite. Our results highlight the critical role of N, K and water availability for tree seedlings in shallow soils on calcareous bedrock. On these sites, natural tree regeneration is at particular risk from episodic drought, a likely consequence of climate change.

  3. Indoleacetaldehyde in Cucumber Seedlings 1

    Science.gov (United States)

    Purves, William K.; Brown, Hugh M.

    1978-01-01

    The presence of indoleacetaldehyde in cucumber (Cucumis sativus L.) cotyledons was demonstrated by thin layer chromatographic RF values in three solvent systems, by the formation and hydrolysis of a bisulfite adduct, and by chemical reduction to indoleethanol and oxidation to indoleacetic acid. Bioassays indicated a minimum indoleacetaldehyde content in etiolated cotyledons of 0.7 μg per kg fresh weight. Tissue samples from all parts of both green and etiolated cucumber seedlings reduced exogenously supplied indoleacetaldehyde to indoleethanol. PMID:16660219

  4. Root architecture and hydraulic conductance in nutrient deprived Pistacia lentiscus L. seedlings.

    Science.gov (United States)

    Trubat, Roman; Cortina, Jordi; Vilagrosa, Alberto

    2012-12-01

    Plants respond to low nutrient availability by modifying root morphology and root system topology. Root responses to nitrogen (N) and phosphorus (P) limitation may affect plant capacity to withstand water stress. But studies on the effect of nutrient availability on plant ability to uptake and transport water are scarce. In this study, we assess the effect of nitrogen and phosphorus limitation on root morphology and root system topology in Pistacia lentiscus L seedlings, a common Mediterranean shrub, and relate these changes to hydraulic conductivity of the whole root system. Nitrogen and phosphorus deprivation had no effect on root biomass, but root systems were more branched in nutrient limited seedlings. Total root length was higher in seedlings subjected to phosphorus deprivation. Root hydraulic conductance decreased in nutrient-deprived seedlings, and was related to the number of root junctions but not to other architectural traits. Our study shows that changes in nutrient availability affect seedling water use by modifying root architecture. Changes in nutrient availability should be taken into account when evaluating seedling response to drought.

  5. The role of nurse functional types in seedling recruitment dynamics of alternative states in rangelands

    Science.gov (United States)

    López, Dardo R.; Cavallero, Laura

    2017-02-01

    In arid ecosystems, recruitment dynamics are limited by harsh environmental conditions and greatly depend on the net outcome of the balance between facilitation and competition. This outcome can change as a consequence of degradation caused by livestock overgrazing. Also, distinct plant species may show a differential response to a common neighbour under the same environmental conditions. Therefore, ecosystem degradation could affect the net balance of plant-plant interactions, which can also depend on the functional traits of potential nurse species. The aim of this study is to assess the influence of alternative degradation states on (i) the density of seedlings of perennial species emerging in four microsite types, and on (ii) the relative interaction intensity (RII) between seedlings and potential nurses belonging to three functional types (deep- and shallow-rooted shrubs, and tussock grasses). During three years, we recorded seedling density of perennial species in four alternative degradation states in grass-shrubby steppes from northwestern Patagonia. The density of emerged seedlings of perennial species decreased sharply as degradation increased, showing non-linear responses in most microsites. Seedling density underneath deep-rooted shrubs was higher than underneath shallow-rooted shrubs and tussock grasses. Also, deep-rooted shrubs were the only functional type that recorded seedling emergence in highly degraded states. Deep-rooted shrubs had facilitative effects on the seedlings emerging and surviving underneath them, independently of ecosystem degradation. In contrast, RII between shallow-rooted shrubs and recently emerged seedlings, switched from positive effects in the less degraded states, to negative effects in the most degraded state. Tussock grasses recorded the weakest intensity of facilitative interactions with recently emerged seedlings, switching to competitive interactions as degradation increased. Our results suggest that species with key

  6. Arbuscular mycorrhiza and water and nutrient supply differently impact seedling performance of dry woodland species with different acquisition strategies

    NARCIS (Netherlands)

    Emiru Birhane, E.B.; Kuyper, T.W.; Sterck, F.J.; Gebrehiwot, K.; Bongers, F.

    2015-01-01

    Background: Arbuscular mycorrhizal (AM) fungi increase seedling survival and performance through enhancement of nutrient and water uptake under stress conditions. Acacia etbaica, A. senegal and Boswellia papyrifera dominate large areas in African drylands where both moisture and nutrients are limite

  7. Diversity of seedling responses to drought

    NARCIS (Netherlands)

    Slot, M.; Poorter, L.

    2007-01-01

    Drought is an important seedling mortality agent in dry and moist tropical forests, and more severe and frequent droughts are predicted in the future. The effect of drought on leaf gas exchange and seedling survival was tested in a dry-down experiment with four tree species from dry and moist forest

  8. Morpho-physiological changes in maize seedling sunder osmotic stress

    Directory of Open Access Journals (Sweden)

    Anđelković Violeta

    2012-01-01

    Full Text Available Drought is a major abiotic stress factor limiting crop growth, development and production worldwide. The objective of this study was to evaluate tolerance to osmotic stress of maize seedlings. More than 6,000 accessions from the Maize Research Institute gene bank were tested under controlled drought (at flowering in Egypt, and afterwards in temperate climate (Serbia and Macedonia. Out of 41 drought tolerant accessions in the field, five inbred lines were chosen for laboratory testing, as well as one drought sensitive line. These genotypes were exposed to 4% polyethylene glycol-PEG (Mr 10000 for 24 h and 48 h. Nine-day-old seedlings compared to control conditions were analyzed in root and shoot length, fresh and dry weight and proline content. Results showed reduction in all parameters under stress, while only proline content increased in all PEG treated genotypes compared to control.

  9. Mycorrhizas on nursery and field seedlings of Quercus garryana.

    Science.gov (United States)

    Southworth, Darlene; Carrington, Elizabeth M; Frank, Jonathan L; Gould, Peter; Harrington, Connie A; Devine, Warren D

    2009-03-01

    Oak woodland regeneration and restoration requires that seedlings develop mycorrhizas, yet the need for this mutualistic association is often overlooked. In this study, we asked whether Quercus garryana seedlings in nursery beds acquire mycorrhizas without artificial inoculation or access to a mycorrhizal network of other ectomycorrhizal hosts. We also assessed the relationship between mycorrhizal infection and seedling growth in a nursery. Further, we compared the mycorrhizal assemblage of oak nursery seedlings to that of conifer seedlings in the nursery and to that of oak seedlings in nearby oak woodlands. Seedlings were excavated and the roots washed and examined microscopically. Mycorrhizas were identified by DNA sequences of the internal transcribed spacer region and by morphotype. On oak nursery seedlings, predominant mycorrhizas were species of Laccaria and Tuber with single occurrences of Entoloma and Peziza. In adjacent beds, seedlings of Pseudotsuga menziesii were mycorrhizal with Hysterangium and a different species of Laccaria; seedlings of Pinus monticola were mycorrhizal with Geneabea, Tarzetta, and Thelephora. Height of Q. garryana seedlings correlated with root biomass and mycorrhizal abundance. Total mycorrhizal abundance and abundance of Laccaria mycorrhizas significantly predicted seedling height in the nursery. Native oak seedlings from nearby Q. garryana woodlands were mycorrhizal with 13 fungal symbionts, none of which occurred on the nursery seedlings. These results demonstrate the value of mycorrhizas to the growth of oak seedlings. Although seedlings in nursery beds developed mycorrhizas without intentional inoculation, their mycorrhizas differed from and were less species rich than those on native seedlings.

  10. Field evaluation of switchgrass seedlings divergently selected for crown node placement

    NARCIS (Netherlands)

    Elbersen, H.W.; Ocumpaugh, W.R.; Hussey, M.A.; Sanderson, M.A.; Tischler, C.R.

    1999-01-01

    Excessive crown node elevation of warm-season grass seedlings is a major limitation to successful establishment. Crown node placement at or above the soil surface limits the opportunity for adventitious root development at the crown node. Switchgrass (Panicum virgatum L.) germplasm selected for low-

  11. Influence of microhabitat on seedling survival and growth of the mediterranean seagrass posidonia oceanica (l.) Delile

    Science.gov (United States)

    Alagna, Adriana; Fernández, Tomás Vega; Terlizzi, Antonio; Badalamenti, Fabio

    2013-03-01

    Early life history phases are crucial stages limiting species distribution and abundance, thus influencing assemblage composition in marine benthic environments. In seagrass systems the period between seed germination and establishment is one of the most vulnerable phases for plant development. This study analyzes the influence of microhabitat structure, in terms of substrate nature and algal canopy, on the persistence and growth over two years of seedlings of Posidonia oceanica, the dominant Mediterranean seagrass. Long time persistence of seedlings only occurred on microhabitats providing vegetated rocky substrates, with a maximum value of 81% on rock covered by Cystoseira spp. No seedling was found on unvegetated sand and gravel after the first year. Seedling growth resulted increased on rock covered by Halopteris spp. and Dilophus spp. than on rock covered by Cystoseira spp. Results suggest that high canopy onto a stable substrate enhances seedling persistence, probably because these allow the best anchorage by roots while hampering water flow. In contrast, turf algal cover promotes better seedling growth, possibly through higher light irradiance and nutrient availability. Our findings support the view that the understanding of the factors controlling early life processes is a necessary prerequisite for the comprehension of seagrass species distribution patterns, colonization and recovery potentials, which, in turn, can guide sound strategies for seagrass management and restoration.

  12. The Potential for Cereal Rye Cover Crops to Host Corn Seedling Pathogens.

    Science.gov (United States)

    Bakker, Matthew G; Acharya, Jyotsna; Moorman, Thomas B; Robertson, Alison E; Kaspar, Thomas C

    2016-06-01

    Cover cropping is a prevalent conservation practice that offers substantial benefits to soil and water quality. However, winter cereal cover crops preceding corn may diminish beneficial rotation effects because two grass species are grown in succession. Here, we show that rye cover crops host pathogens capable of causing corn seedling disease. We isolated Fusarium graminearum, F. oxysporum, Pythium sylvaticum, and P. torulosum from roots of rye and demonstrate their pathogenicity on corn seedlings. Over 2 years, we quantified the densities of these organisms in rye roots from several field experiments and at various intervals of time after rye cover crops were terminated. Pathogen load in rye roots differed among fields and among years for particular fields. Each of the four pathogen species increased in density over time on roots of herbicide-terminated rye in at least one field site, suggesting the broad potential for rye cover crops to elevate corn seedling pathogen densities. The radicles of corn seedlings planted following a rye cover crop had higher pathogen densities compared with seedlings following a winter fallow. Management practices that limit seedling disease may be required to allow corn yields to respond positively to improvements in soil quality brought about by cover cropping.

  13. Within-population variability influences early seedling establishment in four Mediterranean oaks

    Science.gov (United States)

    González-Rodríguez, Victoria; Barrio, Isabel C.; Villar, Rafael

    2012-05-01

    Regeneration of Mediterranean forests is severely limited. Multiple abiotic factors are known to constrain the establishment of woody seedlings at its first phases, such as summer drought or excessive incident radiation, but less attention has been paid to the role of intra-specific variation in seedling performance. In this study we investigate the relative influence of environment (light availability, soil moisture and summer irrigation) and intrinsic factors (seed mass and maternal origin) as determinants of within-population variability in the early establishment of four coexisting Mediterranean oaks (Quercus ilex, Quercus suber, Quercus faginea and Quercus pyrenaica), from emergence and early growth to second-year survival in a field experiment. Seed size was a poor predictor of seed and seedling success. Instead, mother identity showed a stronger effect on seedling performance. Time and percentage of emergence, establishment success and morphological traits varied among seedlings from different maternal trees but main drivers for each variable were different for each species. In addition to a direct effect, in many cases mother-related intrinsic traits and seed mass influenced the effects of environmental conditions on seedling performance. The role of intrinsic factors was masked under ameliorated conditions (i.e. summer irrigation), indicating the relevant role of within-population variability to cope with highly heterogeneous and unpredictable Mediterranean environments.

  14. Growth, water relations and photosynthesis of seedlings and resprouts after fire

    Science.gov (United States)

    Clemente, Adelaide S.; Rego, Francisco C.; Correia, Otília A.

    2005-05-01

    Seasonal patterns of growth, water relations, photosynthesis and leaf characteristics were compared between obligate seeders ( Cistus monspeliensis and Cistus ladanifer) and resprouters ( Arbutus unedo and Pistacia lentiscus) from the first to the second year after fire. We hypothesized that seedlings would be more water-limited than resprouts due to their shallower root systems. Regarding water use strategies, Cistus species are drought semi-deciduous and A. unedo and P. lentiscus are evergreen sclerophylls, therefore, comparisons were based on the relative deviation from mature conspecific plants. Seedlings and resprouts had higher shoot elongation and leaf production than mature plants, and over an extended period. Differences from mature plants were larger in resprouts, with two-fold transpiration, leaf conductance and photosynthesis in late spring/early summer. Seedlings of C. monspeliensis exhibited higher transpiration and leaf conductance than mature plants, while those of C. ladanifer only exhibited higher water potential. Growth increments and ameliorated water relations and photosynthesis after fire were attributed to an increase in water and nutrient availability. The small differences in water relations and photosynthesis between seedlings and mature conspecifics are in accordance with the prediction of seedlings experiencing higher water limitation than resprouts. We attribute these results to differences in root systems: resprouters benefited from an increase in root/shoot ratios and the presence of deep roots whereas Cistus seedlings relied on very shallow roots, which cannot provide assess to deep water during summer. Nevertheless, seedlings did not show evidence of experiencing a more severe water limitation than mature conspecifics, which we attributed to the presence of efficient mechanisms of avoiding and tolerating water stress. The results are discussed in relation to post-fire demography of seeders and resprouters in Mediterranean

  15. Controlled release fertilizer improves quality of container longleaf pine seedlings

    Science.gov (United States)

    R. Kasten Dumroese; Jeff Parkhurst; James P. Barnett

    2005-01-01

    In an operational trial, increasing the amount of nitrogen (N) applied to container longleaf pine seedlings by incorporating controlled release fertilizer (CRF) into the media improved seedling growth and quality. Compared with control seedlings that received 40 mg N, seedlings receiving 66 mg N through CRF supplemented with liquid fertilizer had needles that were 4 in...

  16. Cucumber Seedling Indoleacetaldehyde Oxidase 1

    Science.gov (United States)

    Bower, Peter J.; Brown, Hugh M.; Purves, William K.

    1978-01-01

    Extracts of light-grown Cucumis sativus L. seedlings catalyzed the oxidation of indole-3-acetaldehyde to indole-3-acetic acid. No added cofactors were required. Inhibitor studies indicated that the enzyme is a metalloflavoprotein. While indole-3-aldehyde, benzaldehyde, and phenylacetaldehyde partially inhibited the oxidation of indole-3-acetaldehyde, suggesting that they may serve as alternative substrates, it is proposed that indoleacetaldehyde is the major substrate in vivo. 2,4-Dichlorophenoxyacetic acid strongly inhibited the indoleacetaldehyde oxidase activity, and it is proposed that this enzyme may be subject in vivo to feedback inhibition by indole-3-acetic acid. The enzyme was activated by brief heating or by treatment with mercaptoethanol. PMID:16660220

  17. Seedling quality of common sage (Salvia officinalis L. as affected by seedling production methods

    Directory of Open Access Journals (Sweden)

    Ömer Çalişkan

    2006-09-01

    Full Text Available The study was conducted to determine the effects of four different seedling production methods (i.e., open seedbed, greenhouse seedbed, float system and modified float system on the seedling growth and quality of common sage. Sowing rates were 1 g per m2 in an open seedbed and a greenhouse seedbed system, whereas the sowing rate was one seed per cell in the float and modified float systems. Emergence period, seedling growth period, the fresh and dry weights of aerial parts of seedlings, the fresh and dry weights of roots, seedling height, root height and stem diameter were determined as agronomical observations and measurements. The greenhouse seedling method was found to be superior over the other methods

  18. A review of precipitation and temperature control on seedling emergence and establishment for ponderosa and lodgepole pine forest regeneration

    Science.gov (United States)

    Petrie, Matthew; Wildeman, A.M.; Bradford, John B.; Hubbard, R.M.; Lauenroth, W.K.

    2016-01-01

    The persistence of ponderosa pine and lodgepole pine forests in the 21st century depends to a large extent on how seedling emergence and establishment are influenced by driving climate and environmental variables, which largely govern forest regeneration. We surveyed the literature, and identified 96 publications that reported data on dependent variables of seedling emergence and/or establishment and one or more independent variables of air temperature, soil temperature, precipitation and moisture availability. Our review suggests that seedling emergence and establishment for both species is highest at intermediate temperatures (20 to 25 °C), and higher precipitation and higher moisture availability support a higher percentage of seedling emergence and establishment at daily, monthly and annual timescales. We found that ponderosa pine seedlings may be more sensitive to temperature fluctuations whereas lodgepole pine seedlings may be more sensitive to moisture fluctuations. In a changing climate, increasing temperatures and declining moisture availability may hinder forest persistence by limiting seedling processes. Yet, only 23 studies in our review investigated the effects of driving climate and environmental variables directly. Furthermore, 74 studies occurred in a laboratory or greenhouse, which do not often replicate the conditions experienced by tree seedlings in a field setting. It is therefore difficult to provide strong conclusions on how sensitive emergence and establishment in ponderosa and lodgepole pine are to these specific driving variables, or to investigate their potential aggregate effects. Thus, the effects of many driving variables on seedling processes remain largely inconclusive. Our review stresses the need for additional field and laboratory studies to better elucidate the effects of driving climate and environmental variables on seedling emergence and establishment for ponderosa and lodgepole pine.

  19. Wind-dispersed seed deposition patterns and seedling recruitment of Artemisia halodendron in a moving sandy land.

    Science.gov (United States)

    Li, Feng-Rui; Wang, Tao; Zhang, Ai-Sheng; Zhao, Li-Ya; Kang, Ling-Fen; Chen, Wen

    2005-07-01

    Artemisia halodendron is a native sub-shrub that occurs mainly in moving and semi-fixed sandy lands in Inner Mongolia, China. Information on the spatial patterns of wind-dispersed seed deposition and seedling recruitment of A. halodendron inhabiting moving sandy lands is very limited. The aim of this study was to examine wind-dispersed seed deposition patterns and post-dispersal recruitment of A. halodendron seedlings. * The spatial patterns of wind-dispersed seed deposition and seedling recruitment of A. halodendron were examined by investigating the numbers of deposited seeds, emerged and surviving seedlings using sampling points at a range of distances from the parent plant in eight compass directions for two consecutive growing seasons. * Wind-dispersed seed deposition showed considerable variation between directions and years. Wind transported A. halodendron seeds only a few meters away from the parent plant in all eight directions. Seedling emergence and establishment also showed between-direction and between-year variability, but the spatial pattern of seedling distribution differed from that of seed deposition. Only a very small fraction (seeds emerged in the field and survived for long enough to be included in our seedling censuses at the end of the growing season. * The spatial variation in wind speed and frequency strongly affects the pattern of seed deposition, although the variation in seed deposition does not determine the spatial pattern of seedling recruitment. Seeds of A. halodendron are not dispersed very well by wind. The low probability of recruitment success for A. halodendron seedlings suggests that this species does not rely on seedling recruitment for its persistence and maintenance of population.

  20. Seed Mucilage Improves Seedling Emergence of a Sand Desert Shrub

    OpenAIRE

    Xuejun Yang; Baskin, Carol C.; Baskin, Jerry M.; Guangzheng Liu; Zhenying Huang

    2012-01-01

    The success of seedling establishment of desert plants is determined by seedling emergence response to an unpredictable precipitation regime. Sand burial is a crucial and frequent environmental stress that impacts seedling establishment on sand dunes. However, little is known about the ecological role of seed mucilage in seedling emergence in arid sandy environments. We hypothesized that seed mucilage enhances seedling emergence in a low precipitation regime and under conditions of sand buria...

  1. Ostryopsis davidiana seedlings inoculated with ectomycorrhizal fungi facilitate formation of mycorrhizae on Pinus tabulaeformis seedlings.

    Science.gov (United States)

    Bai, Shu-Lan; Li, Guo-Lei; Liu, Yong; Kasten Dumroese, R; Lv, Rui-Heng

    2009-08-01

    Reforestation in China is important for reversing anthropogenic activities that degrade the environment. Pinus tabulaeformis is desired for these activities, but survival and growth of seedlings can be hampered by lack of ectomycorrhizae. When outplanted in association with Ostryopsis davidiana plants on reforestation sites, P. tabulaeformis seedlings become mycorrhizal and survival and growth are enhanced; without O. davidiana, pines often remain without mycorrhizae and performance is poorer. To better understand this relationship, we initiated an experiment using rhizoboxes that restricted root and tested the hypothesis that O. davidiana seedlings facilitated ectomycorrhizae formation on P. tabulaeformis seedlings through hyphal contact. We found that without O. davidiana seedlings, inocula of five indigenous ectomycorrhizal fungi were unable to grow and associate with P. tabulaeformis seedlings. Inocula placed alongside O. davidiana seedlings, however, resulted in enhanced growth and nutritional status of O. davidiana and P. tabulaeformis seedlings, and also altered rhizosphere pH and phosphatase activity. We speculate that these species form a common mycorrhizal network and this association enhances outplanting performance of P. tabulaeformis seedlings used for forest restoration.

  2. Effect of petroleum products on mangrove seedlings

    Digital Repository Service at National Institute of Oceanography (India)

    Jagtap, T.G.; Untawale, A.G.

    seen. General damage in both the species were burning, yellowing and wilting of the leaves associated with root damage causing retardation of growth. Extensive leaf fall in Avicennia seedlings resulted in its mortality...

  3. Virulence of Fusarium species to alfalfa seedlings

    Directory of Open Access Journals (Sweden)

    Krnjaja Vesna

    2005-01-01

    Full Text Available In in vitro conditions, virulence of 91 isolates of species Fusarium genus (F. oxysporum, F. solani, F. acuminatum, F. equiseti, F. arthrosporioides, F. prolifera- tum, F. avenaceum, F. semitectum, F. tricinctum, F. sporotrichioides and F. graminearum towards alfalfa seedlings was investigated. Isolates of investigated species originated from diseased alfalfa plants collected at four locations in Serbia based on symptoms of wilting caused by Fusarium and root rotting. Pathogenicity and virulence of investigated isolates of Fusarium spp. were determined by visual evaluation of inoculated seedlings of cultivar K28 in laboratory conditions. All isolated of investigated species had pathogenic effect on alfalfa seedlings which expressed symptoms such as necrosis of root, moist rotting and "melting of seedlings". Colour of necrotic root tissue varied from light brown, brown lipstick red to explicit black, depending on the Fusarium species. Strong virulence was established in 48 isolates, medium virulence in 31 and weak virulence in 12 isolates.

  4. Virulence of Fusarium species to alfalfa seedlings

    Directory of Open Access Journals (Sweden)

    Krnjaja Vesna

    2005-01-01

    Full Text Available In in vitro conditions, virulence of 91 isolates of species Fusarium genus (F. oxysporum, F. solani, F. acuminatum, F. equiseti, F. arthrosporioides, F. proliferatum, F. avenaceum, F. semitectum, F. tricinctum, F. sporotrichioides and F. graminearum towards alfalfa seedlings was investigated. Isolates of investigated species originated from diseased alfalfa plants collected on four locations in Serbia based on symptoms of wilting caused by fusarium and root rotting. Pathogenicity and virulence of investigated isolates of Fusarium spp. were determined by visual evaluation of inoculated seedlings of cultivars K28 in laboratory conditions. All isolated of investigated species had pathogenic effect on alfalfa seedlings, which expressed symptoms such as necrosis of root, moist rotting and "melting of seedlings". Colour of necrotic root tissue varied from light brown, brown, lipstick red to explicit black, depending on the Fusarium species. Strong virulence was established in 48 isolates, medium virulence in 31 and weak virulence in 12 isolates.

  5. Morphoanatomy of Serjania communis Cambess. seedling (Sapindaceae

    Directory of Open Access Journals (Sweden)

    Willian Adriano Lira Lopes

    2015-07-01

    Full Text Available Serjania communis Cambess. (Sapindaceae is a plant with climbing habit and occurs relatively often in Paraná State, Brazil. The fruits were collected at the 'Parque dos Pioneiros' a remnant of subtropical forest in Maringá, Paraná State, Brazil. The seedlings obtained in the greenhouse were described according to traditional techniques in plant morphology. Seedlings were embedded in historesin and sectioned in rotation microtome. The fruit is the samaroid type, the seeds have about 3 mm in length and brown color. Seedlings are epigeal phanerocotylar. The seedlings have a hairy hypocotyl, foliaceous cotyledons, reduced epicotyl, and two opposite eophylls. The root is diarch, the hypocotyl shows root-stem transition structure, stem epicotyl, and dorsiventral and hypostomatous cotyledons and eophylls. 'Tirodendros' with 45 days of age do not develop cambial variant.

  6. Belowground Competition Directs Spatial Patterns of Seedling Growth in Boreal Pine Forests in Fennoscandia

    Directory of Open Access Journals (Sweden)

    E. Petter Axelsson

    2014-09-01

    Full Text Available Aboveground competition is often argued to be the main process determining patterns of natural forest regeneration. However, the theory of multiple resource limitation suggests that seedling performance also depends on belowground competition and, thus, that their relative influence is of fundamental importance. Two approaches were used to address the relative importance of above- and below-ground competition on regeneration in a nutrient-poor pine (Pinus sylvestris boreal forest. Firstly, seedling establishment beneath trees stem-girdled 12 years ago show that a substantial proportion of the seedlings were established within two years after girdling, which corresponds to a time when nutrient uptake by tree roots was severely reduced without disrupting water transport to the tree canopy, which consequently was maintained. The establishment during these two years also corresponds to abundances high enough for normal stand replacement. Secondly, surveys of regeneration within forest gaps showed that surrounding forests depressed seedlings, so that satisfactory growth occurred only more than 5 m from forest edges and that higher solar radiation in south facing edges was not enough to mediate these effects. We conclude that disruption of belowground competitive interactions mediates regeneration and, thus, that belowground competition has a strong limiting influence on seedling establishment in these forests.

  7. Drought and shade deplete nonstructural carbohydrate reserves in seedlings of five temperate tree species.

    Science.gov (United States)

    Maguire, Andrea J; Kobe, Richard K

    2015-12-01

    Plants that store nonstructural carbohydrates (NSC) may rely on carbon reserves to survive carbon-limiting stress, assuming that reserves can be mobilized. We asked whether carbon reserves decrease in resource stressed seedlings, and if NSC allocation is related to species' relative stress tolerances. We tested the effects of stress (shade, drought, and defoliation) on NSC in seedlings of five temperate tree species (Acer rubrum Marsh., Betula papyrifera Marsh., Fraxinus americana L ., Quercus rubra L., and Quercus velutina Lam.). In a greenhouse experiment, seedlings were subjected to combinations of shade, drought, and defoliation. We harvested seedlings over 32-97 days and measured biomass and NSC concentrations in stems and roots to estimate depletion rates. For all species and treatments, except for defoliation, seedling growth and NSC accumulation ceased. Shade and drought combined caused total NSC decreases in all species. For shade or drought alone, only some species experienced decreases. Starch followed similar patterns as total NSC, but soluble sugars increased under drought for drought-tolerant species. These results provide evidence that species deplete stored carbon in response to carbon limiting stress and that species differences in NSC response may be important for understanding carbon depletion as a buffer against shade- and drought-induced mortality.

  8. The Fungicide Phosphonate Disrupts the Phosphate-Starvation Response in Brassica nigra Seedlings.

    Science.gov (United States)

    Carswell, C.; Grant, B. R.; Theodorou, M. E.; Harris, J.; Niere, J. O.; Plaxton, W. C.

    1996-01-01

    The development of Brassica nigra seedlings over 20 d of growth was disrupted by the fungicide phosphonate (Phi) in a manner inversely correlated with nutritional inorganic phosphate (Pi) levels. The growth of Pi-sufficient (1.25 mM Pi) seedlings was suppressed when 10, but not 5, mM Phi was added to the nutrient medium. In contrast, the fresh weights and root:shoot ratios of Pi-limited (0.15 mM) seedlings were significantly reduced at 1.5 mM Phi, and they progressively declined to about 40% of control values as medium Phi concentration was increased to 10 mM. Intracellular Pi levels generally decreased in Phi-treated seedlings, and Phi accumulated in leaves and roots to levels up to 6- and 16-fold that of Pi in Pi-sufficient and Pi-limited plants, respectively. Extractable activities of the Pi-starvation-inducible enzymes phosphoenolpyruvate phosphatase and inorganic pyrophosphate-dependent phosphofructokinase were unaltered in Pi-sufficient seedlings grown on 5 or 10 mM Phi. However, when Pi-limited seedlings were grown on 1.5 to 10 mM Phi (a) the induction of phosphoenolpyruvate phosphatase and inorganic pyrophosphate-dependent phosphofructokinase activities by Pi limitation was reduced by 40 to 90%, whereas (b) soluble protein concentrations and the activities of the ATP-dependent phosphofructokinase and pyruvate kinase were unaffacted. It is concluded that Phi specifically interrupts processes involved in regulation of the Pi-starvation response in B. nigra.

  9. Morphoanatomy of Serjania communis Cambess. seedling (Sapindaceae)

    OpenAIRE

    2015-01-01

    Serjania communis Cambess. (Sapindaceae) is a plant with climbing habit and occurs relatively often in Paraná State, Brazil. The fruits were collected at the 'Parque dos Pioneiros' a remnant of subtropical forest in Maringá, Paraná State, Brazil. The seedlings obtained in the greenhouse were described according to traditional techniques in plant morphology. Seedlings were embedded in historesin and sectioned in rotation microtome. The fruit is the samaroid type, the seeds have about 3 mm in l...

  10. Wind-dispersed Seed Deposition Patterns and Seedling Recruitment of Artemisia halodendron in a Moving Sandy Land

    OpenAIRE

    LI, FENG-RUI; Wang, Tao; ZHANG, AI-SHENG; ZHAO, LI-YA; KANG, LING-FEN; Chen, Wen

    2005-01-01

    • Background and Aims Artemisia halodendron is a native sub-shrub that occurs mainly in moving and semi-fixed sandy lands in Inner Mongolia, China. Information on the spatial patterns of wind-dispersed seed deposition and seedling recruitment of A. halodendron inhabiting moving sandy lands is very limited. The aim of this study was to examine wind-dispersed seed deposition patterns and post-dispersal recruitment of A. halodendron seedlings.

  11. Transplant shock of northern red oak seedlings following simulated drought as influenced by root morphology

    Science.gov (United States)

    Douglass F. Jacobs; Francis Salifu; Anthony Davis

    2005-01-01

    Transplant shock, implicated by depressed seedling physiological response associated with moisture or nutrient stress immediately following planting, limits early plantation establishment. We investigated the impacts of simulated drought and transplant root volume on predawn leaf xylem water potential, photosynthetic assimilation rates, stomatal conductance, and growth...

  12. Influence of plant-parasitic nematodes on longleaf pine seedlings.

    Science.gov (United States)

    Ruehle, J L

    1973-01-01

    Seedlings of longleaf pine (Pinus palustris) were grown in 20-cm pots for 5 to 7 months in the greenhouse following inoculation with a high or low level of one of seven species of plant-parasitic nematodes. Belonolaimus longicaudatus and Helicotylenchus dihystera had no effect on seedling growth. High inoculum densities of Hoplolaimus galeatus and Tylenchorhynchus claytoni caused a significant reduction of fresh weight of seedling roots. Root and top weights of seedlings grown in soil infested with Meloidodera floridensis or Pratylenchus brachyurus were significantly less than those of seedlings in noninfested soil. Root growth of seedlings was stimulated by the higher inoculum density of Scutellonema brachyurum.

  13. Ecophysiological variation in two provenances of Pinus flexilis seedlings across an elevation gradient from forest to alpine.

    Science.gov (United States)

    Reinhardt, Keith; Castanha, Cristina; Germino, Matthew J; Kueppers, Lara M

    2011-06-01

    Climate change is predicted to cause upward shifts in forest tree distributions, which will require seedling recruitment beyond current forest boundaries. However, predicting the likelihood of successful plant establishment beyond current species' ranges under changing climate is complicated by the interaction of genetic and environmental controls on seedling establishment. To determine how genetics and climate may interact to affect seedling establishment, we transplanted recently germinated seedlings from high- and low-elevation provenances (HI and LO, respectively) of Pinus flexilis in common gardens arrayed along an elevation and canopy gradient from subalpine forest into the alpine zone and examined differences in physiology and morphology between provenances and among sites. Plant dry mass, projected leaf area and shoot:root ratios were 12-40% greater in LO compared with HI seedlings at each elevation. There were no significant changes in these variables among sites except for decreased dry mass of LO seedlings in the alpine site. Photosynthesis, carbon balance (photosynthesis/respiration) and conductance increased >2× with elevation for both provenances, and were 35-77% greater in LO seedlings compared with HI seedlings. There were no differences in dark-adapted chlorophyll fluorescence (Fv/Fm) among sites or between provenances. Our results suggest that for P. flexilis seedlings, provenances selected for above-ground growth may outperform those selected for stress resistance in the absence of harsh climatic conditions, even well above the species' range limits in the alpine zone. This indicates that forest genetics may be important to understanding and managing species' range adjustments due to climate change.

  14. [Usefulness of the Centrifuge Accommodation Module for analyzing gravity responses in plant seedlings].

    Science.gov (United States)

    Hoson, T

    2001-10-01

    Onboard centrifuges are indispensable tools for clarifying the effects of microgravity on various physiological processes in plant seedlings. Centrifuges are basically attached to the incubators designed for the International Space Station (ISS). However, because of the limitation in size, that loaded to the Cell Biology Experiment Facility (CBEF) is usable only to some small seedlings such as Arabidopsis. The Centrifuge Accommodation Module (CAM) has great advantages in the size and the amounts of plant materials feasible to load, the quality of acceleration produced, and the easiness of operation on it. The CAM is an apparatus that characterizes the ISS most and its construction on schedule is highly expected.

  15. Assessment of salinity tolerance in rice using seedling based morpho-physiological indices

    Directory of Open Access Journals (Sweden)

    Syed Adeel Zafar

    2015-08-01

    Full Text Available Background: Salinity is among the most damaging abiotic stresses for rice production which limits its growing area. The present research was conducted to evaluate five rice varieties for salinity tolerance at seedling stage. Methods: Experiment was conducted in triplicate and in two sets. One set was grown as a control (non-stress and other as salt stressed. Salt stress of 15 dS/m was applied to one set of rice seedlings under controlled conditions. Data for different growth related morpho-physiological traits, i.e. germination percentage, root and shoot length, seedling fresh and dry weight, Na+ and K+ uptake were recorded after 15 days of seedling emergence under control as well as salinity condition. Results: Significant differences were observed among the genotypes under both the treatments and interaction of the evaluated traits suggested a significant variability among the rice genotypes under salt stress. NIAB-IRRI-9, Basmati-198 and KSK-133 were proved to be relatively salt tolerant varieties as they showed good performance for the recorded parameters. However, Basmati-385 was observed a salt sensitive variety due to highest reduction in seedling fresh and dry weight along with the maximum Na+ uptake. Conclusion: Based on obtained results, it was concluded that the evaluated morpho-physiological traits were useful to screen rice cultivars for salinity stress. In addition, NIAB-IRRI-9, Basmati-198 and KSK-133 can be used in breeding programs as tolerant check and Basmati-385 can be used as sensitive check.

  16. Can environmental variation affect seedling survival of plants in northeastern Mexico?

    Directory of Open Access Journals (Sweden)

    García Jaime F.

    2011-01-01

    Full Text Available The effects of global warming increase the frequency and intensity of many climate events such as rainfall. We evaluated the effects of environmental conditions on early stage seedling survival of the native thorn scrub species Caesalpinia mexicana A. Gray, Celtis pallida Torr., Cordia boissieri A. DC., and Ebenopsis ebano (Berland. Barneby and J.W. Grimes, during the summer of 2009 and 2010. The experimental design had two factors, two levels of rainfall and three microhabitats of thorn scrub: (i open interspace, (ii thorn scrub edge and (iii under the canopy of dense thorn scrub. In dense thorn scrub, seedling survival was higher for Caesalpinia mexicana and Celtis pallida, and for Cordia boissieri and Ebenopsis ebano seedling survival was higher in dense thorn scrub and thorn scrub edge. The effect of rainfall on seedling survival depended on the year. Rainfall in 2010 and dense thorn scrub increased seedling survival of native species. For survival, the limiting factors of microhabitats appear to change across the years. Besides rainfall events, biological aspects like competition and mycorrhiza effects would need to be considered in models of plant establishment.

  17. Root architecture simulation improves the inference from seedling root phenotyping towards mature root systems.

    Science.gov (United States)

    Zhao, Jiangsan; Bodner, Gernot; Rewald, Boris; Leitner, Daniel; Nagel, Kerstin A; Nakhforoosh, Alireza

    2017-02-01

    Root phenotyping provides trait information for plant breeding. A shortcoming of high-throughput root phenotyping is the limitation to seedling plants and failure to make inferences on mature root systems. We suggest root system architecture (RSA) models to predict mature root traits and overcome the inference problem. Sixteen pea genotypes were phenotyped in (i) seedling (Petri dishes) and (ii) mature (sand-filled columns) root phenotyping platforms. The RSA model RootBox was parameterized with seedling traits to simulate the fully developed root systems. Measured and modelled root length, first-order lateral number, and root distribution were compared to determine key traits for model-based prediction. No direct relationship in root traits (tap, lateral length, interbranch distance) was evident between phenotyping systems. RootBox significantly improved the inference over phenotyping platforms. Seedling plant tap and lateral root elongation rates and interbranch distance were sufficient model parameters to predict genotype ranking in total root length with an RSpearman of 0.83. Parameterization including uneven lateral spacing via a scaling function substantially improved the prediction of architectures underlying the differently sized root systems. We conclude that RSA models can solve the inference problem of seedling root phenotyping. RSA models should be included in the phenotyping pipeline to provide reliable information on mature root systems to breeding research. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  18. Substrates and nutrient addition rates affect morphology and physiology of Pinus leiophylla seedlings in the nursery stage

    Directory of Open Access Journals (Sweden)

    Buendía_Velázquez MV

    2016-10-01

    Full Text Available Production of forest seedlings is expensive mainly due to the use of inputs such as peat moss and fertilizers. Seedling survival in field conditions is low when seedlings with limited internal nutrient reserves are used in low fertility sites. In this work, raw sawdust and exponential fertilization were tested against peat-moss and constant fertilization, the common components of containerized seedling production systems in Mexico. The experiment was carried out under nursery conditions by using a complete randomized experimental design with a 2×2 factorial arrangement. Two substrates   peat-moss (PM and sawdust (SA   and two nutrient addition rates   constant (CR and exponential (ER   were tested. The response of seedlings was assessed based on diameter at the root collar, seedling height, dry weight (shoot, root, total and 100-needle, Dickson quality index (DQI, slenderness index (SI, and foliar nutrient concentrations and contents. Analysis of variance indicated that the substrate significantly affect all dry weights, with the greatest biomass observed for PM. Similarly, DQI and SI were affected by the substrate, with PM showing the best DQI and highest SI. Neither plant quality variables nor dry weights were affected by nutrient addition rates. Both substrate and nutrient addition rate significantly affected N, P, and K foliar concentrations. At the end of the production cycle, SA promoted higher foliar concentrations of N and P than PM, but not those of K. This suggests that K limited the growth of seedlings in sawdust, likely due to the low capacity of this substrate to adsorb K. ER produced needle concentrations of N, P, and K significantly higher than those of CR (2.65 vs. 2.26 %, 2303 vs. 2011 ppm, and 4235 vs. 3949 ppm, respectively. Our results indicate that ER is likely to give rise to more suited seedlings for outplanting in low fertility sites than CR.

  19. Simulated drought influences oxidative stress in Zea mays seedlings ...

    African Journals Online (AJOL)

    Simulated drought influences oxidative stress in Zea mays seedlings. ... Bayero Journal of Pure and Applied Sciences. Journal Home · ABOUT ... Seedlings were grown for 8 weeks in nursery bags filled with sandy-loam soil in two categories.

  20. The fungi causin damping-off of carrot seedlings

    Directory of Open Access Journals (Sweden)

    Bogdan Nowicki

    2013-12-01

    Full Text Available When 136 samples of dying carrot seedlings from several fields were analyzed Alternaria rudicina proved to be the most common seedling pathogen (41%, followed by some Fusarium species (27%, mostly F. avenaceum.The less common seedling pathogens were Pythium spp. (13%, Phoma spp.(2,5% and Botrytis cinerea (1,4%. Some other fungi (Bipolaris sorokiniana, Sclerotinia sclerotiorum, Stemphylium botryosym and Ulocladium consortiale were found in less than 1% of seedlings examined.

  1. Containers of Attalea funifera fibers to produce eucalyptus seedlings

    Directory of Open Access Journals (Sweden)

    Andrea Vita Reis Mendonça

    2016-09-01

    Full Text Available The aim of this study was to assess the technical feasibility of using biodegradable containers made of fiber waste of Attalea funifera Martius to produce seedling of Eucalyptus camaldulensis Dehnh. The work was carried out in three stages: manufacture of piassava fiber containers, seedling production and field simulation. The experiment of seedling production was in completely randomized design, with two treatments (polyethylene tube and biodegradable container and 10 repetitions, with 64 seedlings per repetition. After 93 days, seedlings were evaluated based on quality variables. The simuation of initial growth of seedlings in the field consisted in planting seedlings in containers of 11L, in completely randomized design, with three treatments: seedlings produced in polyethylene tubes; seedlings produced in biodegradable containers, without removal of the container during planting; and seedlings produced in biodegradable containers, with removal of the container at planting, with ten repetitions, with one seedling by repetition. The biodegradable container withstood the production cycle and resulted in seedlings within acceptable standards quality. The use of biodegradable container, made of palm fibers, waived the removal of this vessel in the final planting.

  2. Containers of Attalea funifera fibers to produce eucalyptus seedlings

    Directory of Open Access Journals (Sweden)

    Andrea Vita Reis Mendonça

    2016-09-01

    Full Text Available The aim of this study was to assess the technical feasibility of using biodegradable containers made of fiber waste of Attalea funifera Martius to produce seedling of Eucalyptus camaldulensis Dehnh. The work was carried out in three stages: manufacture of piassava fiber containers, seedling production and field simulation. The experiment of seedling production was in completely randomized design, with two treatments (polyethylene tube and biodegradable container and 10 repetitions, with 64 seedlings per repetition. After 93 days, seedlings were evaluated based on quality variables. The simuation of initial growth of seedlings in the field consisted in planting seedlings in containers of 11L, in completely randomized design, with three treatments: seedlings produced in polyethylene tubes; seedlings produced in biodegradable containers, without removal of the container during planting; and seedlings produced in biodegradable containers, with removal of the container at planting, with ten repetitions, with one seedling by repetition. The biodegradable container withstood the production cycle and resulted in seedlings within acceptable standards quality. The use of biodegradable container, made of palm fibers, waived the removal of this vessel in the final planting.

  3. [Influence of seedling assortment on Panax notoginseng growth and yield].

    Science.gov (United States)

    Cui, X; Wang, C; Chen, Z

    1998-02-01

    Making Panax notoginseng seedling assortment according to seedling size before transplanting, the result shows that the influence is better, the yield of root tuber and fruit is higher. Culturing good seedling is the fundamental measure to increase yield of P. notoginseng.

  4. Seed mucilage improves seedling emergence of a sand desert shrub.

    Directory of Open Access Journals (Sweden)

    Xuejun Yang

    Full Text Available The success of seedling establishment of desert plants is determined by seedling emergence response to an unpredictable precipitation regime. Sand burial is a crucial and frequent environmental stress that impacts seedling establishment on sand dunes. However, little is known about the ecological role of seed mucilage in seedling emergence in arid sandy environments. We hypothesized that seed mucilage enhances seedling emergence in a low precipitation regime and under conditions of sand burial. In a greenhouse experiment, two types of Artemisia sphaerocephala achenes (intact and demucilaged were exposed to different combinations of burial depth (0, 5, 10, 20, 40 and 60 mm and irrigation regimes (low, medium and high, which simulated the precipitation amount and frequency in May, June and July in the natural habitat, respectively. Seedling emergence increased with increasing irrigation. It was highest at 5 mm sand burial depth and ceased at burial depths greater than 20 mm in all irrigation regimes. Mucilage significantly enhanced seedling emergence at 0, 5 and 10 mm burial depths in low irrigation, at 0 and 5 mm burial depths in medium irrigation and at 0 and 10 mm burial depths in high irrigation. Seed mucilage also reduced seedling mortality at the shallow sand burial depths. Moreover, mucilage significantly affected seedling emergence time and quiescence and dormancy percentages. Our findings suggest that seed mucilage plays an ecologically important role in successful seedling establishment of A. sphaerocephala by improving seedling emergence and reducing seedling mortality in stressful habitats of the sandy desert environment.

  5. Herbivory on temperate rainforest seedlings in sun and shade: resistance, tolerance and habitat distribution.

    Directory of Open Access Journals (Sweden)

    Cristian Salgado-Luarte

    Full Text Available Differential herbivory and/or differential plant resistance or tolerance in sun and shade environments may influence plant distribution along the light gradient. Embothrium coccineum is one of the few light-demanding tree species in the temperate rainforest of southern South America, and seedlings are frequently attacked by insects and snails. Herbivory may contribute to the exclusion of E. coccineum from the shade if 1 herbivory pressure is greater in the shade, which in turn can result from shade plants being less resistant or from habitat preferences of herbivores, and/or 2 consequences of damage are more detrimental in the shade, i.e., shade plants are less tolerant. We tested this in a field study with naturally established seedlings in treefall gaps (sun and forest understory (shade in a temperate rainforest of southern Chile. Seedlings growing in the sun sustained nearly 40% more herbivore damage and displayed half of the specific leaf area than those growing in the shade. A palatability test showed that a generalist snail consumed ten times more leaf area when fed on shade leaves compared to sun leaves, i.e., plant resistance was greater in sun-grown seedlings. Herbivore abundance (total biomass was two-fold greater in treefall gaps compared to the forest understory. Undamaged seedlings survived better and showed a slightly higher growth rate in the sun. Whereas simulated herbivory in the shade decreased seedling survival and growth by 34% and 19%, respectively, damaged and undamaged seedlings showed similar survival and growth in the sun. Leaf tissue lost to herbivores in the shade appears to be too expensive to replace under the limiting light conditions of forest understory. Following evaluations of herbivore abundance and plant resistance and tolerance in contrasting light environments, we have shown how herbivory on a light-demanding tree species may contribute to its exclusion from shade sites. Thus, in the shaded forest understory

  6. Organ-coordinated response of early post-germination mahogany seedlings to drought.

    Science.gov (United States)

    Horta, Lívia P; Braga, Márcia R; Lemos-Filho, José P; Modolo, Luzia V

    2014-04-01

    Water deficit tolerance during post-germination stages is critical for seedling recruitment. In this work, we studied the effect of water deficit on morphological and biochemical responses in different organs of newly germinated mahogany (Swietenia macrophylla King) seedlings, a woody species that occurs in the Amazon rainforest. The root : shoot ratio increased under water deficit. The leaf number and water potential were not altered, although reductions in leaf area and stomatal conductance were observed. Osmotic potential became more negative in leaves of seedlings under severe stress. Water deficit increased fructose, glucose, sucrose and myo-inositol levels in leaves. Stems accumulated fructose, glucose and l-proline. Nitric oxide (NO) levels increased in the vascular cylinder of roots under severe stress while superoxide anion levels decreased due to augmented superoxide dismutase activity in this organ. Water deficit induced glutathione reductase activity in both roots and stems. Upon moderate or severe stress, catalase activity decreased in leaves and remained unaffected in the other seedling organs, allowing for an increase of hydrogen peroxide (H2O2) levels in leaves. Overall, the increase of signaling molecules in distinct organs-NO in roots, l-proline in stems and H2O2 and myo-inositol in leaves-contributed to the response of mahogany seedlings to water deficit by triggering biochemical processes that resulted in the attenuation of oxidative stress and the establishment of osmotic adjustment. Therefore, this body of evidence reveals that the development of newly germinated mahogany seedlings may occur in both natural habitats and crop fields even when water availability is greatly limited.

  7. Comparative proteomic analysis reveals molecular mechanism of seedling roots of different salt tolerant soybean genotypes in responses to salinity stress

    Directory of Open Access Journals (Sweden)

    Hongyu Ma

    2014-09-01

    Full Text Available Salinity stress is one of the major abiotic stresses that limit agricultural yield. To understand salt-responsive protein networks in soybean seedling, the extracted proteins from seedling roots of two different genotypes (Lee 68 and Jackson were analyzed under salt stress by two-dimensional polyacrylamide gel electrophoresis. Sixty-eight differentially expressed proteins were detected and identified. The identified proteins were involved in 13 metabolic pathways and cellular processes. Proteins correlated to brassinosteroid and gilbberellin signalings were significantly increased only in the genotype Lee 68 under salt stress; abscisic acid content was positively correlated with this genotype; proteins that can be correlated to Ca2+ signaling were more strongly enhanced by salt stress in the seedling roots of genotype Lee 68 than in those of genotype Jackson; moreover, genotype Lee 68 had stronger capability of reactive oxygen species scavenging and cell K+/Na+ homeostasis maintaining in seedling roots than genotype Jackson under salt stress. Since the genotype Lee 68 has been described in literature as being tolerant and Jackson as sensitive, we hypothesize that these major differences in the genotype Lee 68 might contribute to salt tolerance. Combined with our previous comparative proteomics analysis on seedling leaves, the similarities and differences between the salt-responsive protein networks found in the seedling leaves and roots of both the genotypes were discussed. Such a result will be helpful in breeding of salt-tolerant soybean cultivars.

  8. The use of compost in afforestation of Mediterranean areas: Effects on soil properties and young tree seedlings.

    Science.gov (United States)

    Larchevêque, Marie; Ballini, Christine; Korboulewsky, Nathalie; Montès, Nicolas

    2006-10-01

    In Mediterranean frequently burnt areas, fire and erosion result in the decrease of soil fertility, so afforestation is a major concern. We carried out an in situ experiment of compost amendment to improve survival and growth of planted tree seedlings. One-year-tree seedlings of native species (Quercus ilex, Pinus halepensis and Pinus pinea) were planted on a frequently burnt calcareous site. Three rates of fresh co-composted sewage sludge and greenwastes (control without compost, 20 and 40 kg m(-2) of compost) were incorporated into the soil at each seedling stem. Changes of soil properties and tree development were studied during 3 years (2001-2003) and 2 years (2002-2003) respectively. The compost improved survival of Quercus ilex and Pinus pinea seedlings in severe drought conditions, but had no effect on Pinus halepensis. For all species seedling length and radial growth and NPK nutrition were increased for both rates of amendment. Amendment improved soil fertility, but available P concentration increased 13 fold in the neighbouring soil of seedlings amended at the maximal rate compared to control. However, amendment did not significantly increase concentrations of Cd, Cr, Ni and Pb in soils or tree seedlings. It increased Cu and Zn total and available concentrations in soils, while foliar Cu and Zn concentrations in the seedlings remained similar in all plots. Compost can efficiently help afforestation of dry soils with low organic matter content. However, sewage sludge concentrations in P, and to a lesser extent in Cu and Zn, limit rates of application that can be applied without environmental hazard.

  9. A comparison of growth, photosynthetic capacity and water stress in Eucalyptus globulus coppice regrowth and seedlings during early development.

    Science.gov (United States)

    Drake, Paul L; Mendham, Daniel S; White, Don A; Ogden, Gary N

    2009-05-01

    Eucalyptus globulus Labill., a globally significant plantation species, is grown commercially in a multiple rotation framework. Second and subsequent crops of E. globulus may be established either by allowing the cut stumps to resprout (commonly referred to as coppice) or by replanting a new crop of seedlings. Currently, long-term growth data comparing coppice and seedling productivity in second or later rotations in southern Australia is limited. The capacity to predict productivity using these tools is dependent on an understanding of the physiology of seedlings and coppice in response to light, water and nutrient supply. In this study, we compared the intrinsic (independent of the immediate environment) and native (dependent on the immediate environment) physiology of E. globulus coppice and second-generation seedlings during their early development in the field. Coppice not only grew more rapidly, but also used more water and drew on stored soil water to a depth of at least 4.5 m during the first 2 years of growth, whereas the seedlings only accessed the top 0.9 m of the soil profile. During the same period, there was no significant difference between coppice and seedlings in either their stomatal response to leaf-to-air vapour pressure difference (D) or intrinsic water-use efficiency; CO(2)- and light-saturated rates of photosynthesis were greater in seedlings than that in coppice as were the quantum yield of photosynthesis and total leaf chlorophyll content. Thus, at a leaf scale, seedlings are potentially more productive per unit leaf area than coppice during early development, but this is not realised under ambient conditions. The underlying cause of this inherent difference is discussed in the context of the allocation of resources to above- and below-ground organs during early development.

  10. Characterization of rhizobacteria associated with weed seedlings.

    Science.gov (United States)

    Kremer, R J; Begonia, M F; Stanley, L; Lanham, E T

    1990-06-01

    Rhizobacteria were isolated from seedlings of seven economically important weeds and characterized for potential phytopathogenicity, effects on seedling growth, and antibiosis to assess the possibility of developing deleterious rhizobacteria as biological control agents. The abundance and composition of rhizobacteria varied among the different weed species. For example, fluorescent pseudomonads represented from 11 to 42% of the total rhizobacterial populations from jimsonweed and lambsquarters, respectively. Other bacteria frequently isolated were nonfluorescent pseudomonads, Erwinia herbicola, Alcaligenes spp., and Flavobacterium spp. Only 18% of all isolates were potentially phytopathogenic, based on an Escherichia coli indicator bioassay. However, the proportion of isolates that inhibited growth in seedling assays ranged from 35 to 65% depending on the weed host. Antibiosis was most prevalent among isolates of fluorescent Pseudomonas spp., the activity of which was due to siderophore production in over 75% of these isolates. Overall, rhizobacterial isolates exhibited a complex array of properties that were inconsistent with accepted definitions for plant growth-promoting and deleterious rhizobacteria. It is suggested that for development of effective biological control agents for weed control, deleterious rhizobacteria must be screened directly on host seedlings and must possess several properties including high colonizing ability, specific phytotoxin production, and resistance or tolerance to antibiotics produced by other rhizosphere microorganisms, and they must either synthesize or utilize other bacterial siderophores.

  11. How do riparian woody seedlings survive seasonal drought?

    Science.gov (United States)

    Stella, John C; Battles, John J

    2010-11-01

    In semi-arid regions, a major population limitation for riparian trees is seedling desiccation during the dry season that follows annual spring floods. We investigated the stress response of first-year pioneer riparian seedlings to experimental water table declines (0, 1 and 3 cm day(-1)), focusing on the three dominant cottonwood and willows (family Salicaceae) in California's San Joaquin Basin. We analyzed growth and belowground allocation response to water stress, and used logistic regression to determine if these traits had an influence on individual survival. The models indicate that high root growth (>3 mm day(-1)) and low shoot:root ratios (water-use efficiency for surviving water stress. Both S. gooddingii and sandbar willow (S. exigua) reduced leaf size from controls, whereas Fremont cottonwood (Populus fremontii) sustained a 29% reduction in specific leaf area (from 13.4 to 9.6 m(2) kg(-1)). The functional responses exhibited by Goodding's willow, the more drought-tolerant species, may play a role in its greater relative abundance in dry regions such as the San Joaquin Basin. This study highlights the potential for a shift in riparian forest composition. Under a future drier climate regime or under reduced regulated river flows, our results suggest that willow establishment will be favored over cottonwood.

  12. Water management in hardening Maytenus ilicifolia (Schrad. Planch. seedlings

    Directory of Open Access Journals (Sweden)

    João Alexandre Lopes Dranski

    2017-02-01

    Full Text Available This study evaluated the effects of seedling height and irrigation management on M. ilicilofia seedlings. The experiment used a completely randomized design in a 2 x 3 factorial arrangement. Seedlings of two height classes (greater than or less than 18.0 cm were subjected to three irrigation regimes (daily irrigation, irrigation every other day, and gradual reduction of irrigation. After eight weeks, the morphophysiological and performance attributes of the seedlings were quantified. Gradual reduction of irrigation promoted the highest rate of net carbon assimilation. Irrigating every other day resulted in greater secondary growth rate, biomass accumulation in the shoot and root tissues, and lower electrolyte leakage rate. After planting, these treatments maintained higher leaf relative water content (RWC. RWC in seedlings smaller than 18 cm was significantly higher until the third week after planting. Therefore, larger seedlings submitted to hardening by gradually reducing irrigation improves seedling quality.

  13. Challenges in forest reclamation of marginal lands: a balance between site conditions and seedling quality

    Science.gov (United States)

    Landhäusser, Simon

    2017-04-01

    appropriate seedling qualities to be identified. In this presentation, I will show results from a range of studies that explored the role of seedling characteristics in response to challenging site conditions and explore the need for a balance between the recognition and improvement of limiting site conditions and the availability of quality seedling stock in forest restoration.

  14. Postfire seedling dynamics and performance in Pinus halepensis Mill. populations

    Science.gov (United States)

    Daskalakou, Evangelia N.; Thanos, Costas A.

    2010-09-01

    Postfire dynamics of Aleppo pine seedling density, survival and growth were assessed in five burned forests of Attica, Greece (Stamata, Villia, Avlona, Kapandriti and Agios Stefanos) through the establishment of permanent experimental plots. All emerging seedlings were tagged and their survival and growth monitored at regular intervals. Seedling density dynamics show an initial, steep increase (to maximum values 2.9-4.6 seedlings m -2) followed by a gradual decrease that levels off at the second and third postfire year (1.3-3.0 seedlings m -2); similarly, postfire seedling survival more or less stabilised at 30-50%, 2-3 years after fire. On the basis of density and mortality trends as well as relevant bibliographic data, it is predicted that very dense, mature forests (10.000 trees ha -1 or more) will be reinstated within 15-20 years. During the first 5-7 postfire years, seedling/sapling annual height followed linear trends with various yearly rates, ranging mostly between 8 and 15 cm (and 27-30 cm in two exceptional, fast growing cases). Within an individual growth season, seedling height dynamics were found to follow sigmoid curves with growth increment peaks in mid-spring. The time (on a monthly basis) of seedling emergence did not affect seedling growth or survival. On the other hand, for the first time under natural conditions, it has been shown that cotyledon number per seedling, an indirect measure of both seed size and initial photosynthetic capacity, significantly affected seedling survival but not growth. Seedlings bearing a higher number of cotyledons, presumably derived from larger seeds, showed greater survival at the end of the first postfire year than seedlings with fewer cotyledons. A postfire selective pressure, favouring large seed size, is postulated to counteract with a contrasting one, which favours small seed size, expressed during fire-free conditions.

  15. On the biomechanics of seedling anchorage

    Science.gov (United States)

    Crouzy, Benoît; Edmaier, Katharina; Perona, Paolo

    2014-05-01

    We propose a minimal model for the response of vegetation to pullout constraints at early development stage. We try to capture both the average mechanical properties of the root system and the stochastic component of the uprooting process of seedlings. We identify a minimal set of relevant physical components in the purpose of quantifying the uprooting process: length of the root fibres, elastic response of the fibres and adhesion between the roots and the soil matrix. We present for validation a dataset extracted from Edmaier et al. (under revision), accounting for 98 uprooting experiments using Avena sativa L. seedlings (common oat), growing in non-cohesive sediment under controlled conditions. The corresponding root system has a very simple architecture, with three root fibres of different lengths. The response of the system to the constraint is however complex: the stress-strain signal presents sudden jumps followed by partial elastic recoveries. The analysis of the jumps and partial recoveries gives an insight into the resilience of the system. The anchorage of less mature seedlings rapidly collapses after the peak force has been reached, while more mature seedlings usually recover from partial failures. We explore this crossover with our validation dataset. The type of seedlings we study has been used in flume experiments investigating the feedbacks between the vegetation and the river morphodynamics (see for example Perona et al. (2012)). An understanding of the characteristics of the uprooting curve (maximal uprooting force and total uprooting work) of such vegetation reveals the ability of seedlings to withstand environmental constraints in terms of duration or intensity (see Edmaier et al., under revision), and is therefore helpful for planning future experiments. REFERENCES - P. Perona, P. Molnar, B. Crouzy, E. Perucca, Z. Jiang, S. McLelland, D. Wüthrich, K. Edmaier, R. Francis, C. Camporeale, et al., Biomass selection by floods and related timescales

  16. Maximizing growth of vegetable seedlings in controlled environments at elevated temperature, light and CO/sub 2/

    Energy Technology Data Exchange (ETDEWEB)

    Krizek, D.T.; Bailey, W.A.; Klueter, H.; Liu, R.C.

    1974-01-01

    Seedlings of cucumber Burpee Hybrid, tomato Michigan-Ohio and lettuce Grand Rapids were germinated in the greenhouse for 5, 8, and 11 days respectively, and then grown for 15 days at elevated temperature (30/24/sup 0/C), light (43.1 klx), and CO/sub 2/ (2000 ppm) a 16-hr photoperiod, 65% relative humidity, and fertilized 4 times daily. At the end of this time, they weighed 2 to 4.6 times those grown at standard environmental conditions in the growth chamber (24/18/sup 0/C, 21.5 klx, and 400 ppm CO/sub 2/) and 10 to 25 times those of greenhouse controls kept on natural days (24/18/sup 0/C, 350 ppm CO/sub 2/, and ca 12-hr photoperiod). Leaf expansion of seedlings grown under elevated growth chamber conditions was double that of seedlings in standard growth chamber conditions, and 6 to 7 times greater than under natural days in the greenhouse. Temperature was the most limiting factor for seedling growth. At the levels of light and CO/sub 2/ used in the experiment, CO/sub 2/ was more limiting than light intensity. In general, optimum seedling growth was obtained when temperature, light, and CO/sub 2/ were increased simultaneously. The most striking effects of CO/sub 2/ enrichment were precocious flower bud formation in tomato and cucumber and extensive growth of the lateral buds in all three species.

  17. Effects of Different Pretreatments to the Seed on Seedling Emergence and Growth of Acacia polyacantha

    Directory of Open Access Journals (Sweden)

    Edward Missanjo

    2014-01-01

    Full Text Available Acacia polyacantha Willd. is a multipurpose tree species prioritised as one of the agroforestry tree species in Malawi. However, its use in agroforestry practices is limited by the low seedling growth and survival at the nursery stage. A study was conducted to evaluate the seedling growth and survival of Acacia polyacantha as affected by different pretreatments on the seeds at Malawi College of Forestry and Wildlife nursery, Malawi. Seeds were subjected to five presowing seed treatments methods, namely, immersion in cold water at room temperature for 24 hours, immersion in hot water (100°C for 5 minutes, immersion in concentrated sulfuric acid (0.3 M H2SO4 for 20 minutes, scarification by mechanically nicking using secateurs, and a control where seeds were sown without any treatment. The results indicate that presowing seed treatments have positive influence on the seedling growth and survival percentage. Nicked seeds exhibited the highest significant (P<0.001 performance for vegetative characteristics of height, root collar diameter, number of leaves, and survival percentage compared to other pretreatments. Therefore, it is suggested to use nicking as a pretreatment method on Acacia polyacantha seeds in order to enhance the speed and the amount of early seedling growth at the nursery stage.

  18. Plant SILAC: stable-isotope labelling with amino acids of arabidopsis seedlings for quantitative proteomics.

    Directory of Open Access Journals (Sweden)

    Dominika Lewandowska

    Full Text Available Stable Isotope Labelling by Amino acids in Cell culture (SILAC is a powerful technique for comparative quantitative proteomics, which has recently been applied to a number of different eukaryotic organisms. Inefficient incorporation of labelled amino acids in cell cultures of Arabidopsis thaliana has led to very limited use of SILAC in plant systems. We present a method allowing, for the first time, efficient labelling with stable isotope-containing arginine and lysine of whole Arabidopsis seedlings. To illustrate the utility of this method, we have combined the high labelling efficiency (>95% with quantitative proteomics analyses of seedlings exposed to increased salt concentration. In plants treated for 7 days with 80 mM NaCl, a relatively mild salt stress, 215 proteins were identified whose expression levels changed significantly compared to untreated seedling controls. The 92 up-regulated proteins included proteins involved in abiotic stress responses and photosynthesis, while the 123 down-regulated proteins were enriched in proteins involved in reduction of oxidative stress and other stress responses, respectively. Efficient labelling of whole Arabidopsis seedlings by this modified SILAC method opens new opportunities to exploit the genetic resources of Arabidopsis and analyse the impact of mutations on quantitative protein dynamics in vivo.

  19. Antioxidant activity of seedling growth in selected soybean genotypes (Glycine max (L.) Merrill) responses of submergence

    Science.gov (United States)

    Damanik, R. I.; Marbun, P.; Sihombing, L.

    2016-08-01

    In order to better understand the physiological and biochemical responses relating to direct seeding establishment in soybeans, the plant growth rate and antioxidative defense responses of seedlings in seven Indonesian soybean genotypes (Anjasmoro, Detam-1, Detam-2, Dieng, Grobogan, Tanggamus, and Willis) at different submergence periods (4, and 8 days) were examined. Twelve-day old seedlings were hydroponically grown in limited oxygen conditions. The results showed that the chlorophyll content in soybean seedlings was reduced beginning as early as 4 d under submerged condition, except for Detam-1, Detam-2, and Grobogan genotypes. The dry weight and protein concentration of seedlings were significantly higher at control condition (0 d) than those in submerged condition. The activities of superoxide dismutase (SOD) increased linearly until 8 d submerged for all genotypes. On the other hand, our results showed that catalase (CAT) and ascorbate peroxidase (APX) activities did not work together, meaning that CAT is activated and APX deactivated, or vice versa, in response to submergence conditions, except for Grobogan and Tanggamus genotypes which had an effect on both CAT and APX activities. Submergence stress led to a significant increase in glutathione reductase (GR) together with APX activity for Detam-2 and Dieng genotypes at 8 d submerged.

  20. Effects of soil nitrogen:phosphorus ratio on growth rate of Artemisia ordosica seedlings

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    To address how the ratios of nitrogen and phosphorus (N:P ratios) in soil affect plant growth, we performed a two-factor (soil available N:P ratios and plant density) randomized block pot experiment to examine the relationships between soil N:P ratios, and the N:P ratios and growth rate of Artemisia ordosica seedlings. Under moderate water stress and adequate nutrient status, both soil N:P and plant density influenced the N:P ratios and growth rates of A. ordosica. With the increase of soil N:P ratios, the growth rates of A. ordosica seedlings decreased significantly. With the increase of soil N:P ratios, N:P ratios in A. ordosica seedlings increased significantly. While the nitrogen concentrations in the plant increased slightly, the phosphorus concentrations significantly decreased. With the increase of plant density, the shoot N:P ratios and growth rates significantly decreased, which resulted from soil N:P ratios. Thus, soil N:P ratios influenced the N:P ratios in A. ordosica seedlings, and hence, influenced its growth. Our results suggest that, under adequate nutrient environment, soil N:P ratios can be a limiting factor for plant growth.

  1. Multiple amine oxidases in cucumber seedlings.

    Science.gov (United States)

    Percival, F W; Purves, W K

    1974-10-01

    Cell-free extracts of cucumber (Cucumis sativus L. cv. National Pickling) seedlings were found to have amine oxidase activity when assayed with tryptamine as a substrate. Studies of the effect of lowered pH on the extract indicated that this activity was heterogeneous, and three amine oxidases could be separated by ion exchange chromatography. The partially purified enzymes were tested for their activities with several substrates and for their sensitivities to various amine oxidase inhibitors. One of the enzymes may be a monoamine oxidase, although it is inhibited by some diamine oxidase inhibitors. The other two enzymes have properties more characteristic of the diamine oxidases. The possible relationship of the amine oxidases to indoleacetic acid biosynthesis in cucumber seedlings is discussed.

  2. Arborescent palm seed morphology and seedling distribution

    OpenAIRE

    Rodolfo Salm

    2005-01-01

    This study examines how the seed morphology of two large arborescent palms, Attalea maripa (Aubl.) Mart. and Astrocaryum aculeatum G. Mey, may affect their seed shadow in a seasonally dry Amazonian forest. In addition to being smaller and produced in larger numbers than those of A. aculeatum, A. maripa seeds also presented a substantially lower amount of nutritional reserves available for the embryo. However, A. maripa seedlings were found in much higher numbers than those of A. aculeatum. Th...

  3. Fungi causing dying out of heather seedlings

    Directory of Open Access Journals (Sweden)

    Maria Kowalik

    2012-12-01

    Full Text Available The aim of the study was to determine the fungi causing dying out of one-yearold heather seedlings. Observations were carried out on: 'Amethyst', 'Annemarie', 'Colette', 'Perestroika' and 'Reini'. The shoots revealing necrotic symptoms were plated on PDA medium. 25 species of fungi were isolated. Among them Pestalotia sydowiana, Alternaria alternata, Cylindrocarpon destructans, Leptosphaeria coniothyrium and Epicoccum purpurascens were dominant, while Mammaria echinobotryoides, Phoma leveillei, Kaissleriella subalpina, Botrytis cinerea and Phytophthora cinnamomi occurred less frequently.

  4. Fungi causing dying out of heather seedlings

    OpenAIRE

    Maria Kowalik; Agnieszka Wandzel

    2012-01-01

    The aim of the study was to determine the fungi causing dying out of one-yearold heather seedlings. Observations were carried out on: 'Amethyst', 'Annemarie', 'Colette', 'Perestroika' and 'Reini'. The shoots revealing necrotic symptoms were plated on PDA medium. 25 species of fungi were isolated. Among them Pestalotia sydowiana, Alternaria alternata, Cylindrocarpon destructans, Leptosphaeria coniothyrium and Epicoccum purpurascens were dominant, while Mammaria echinobotryoides, Phoma leveille...

  5. Excess nickel modulates activities of carbohydrate metabolizing enzymes and induces accumulation of sugars by upregulating acid invertase and sucrose synthase in rice seedlings.

    Science.gov (United States)

    Mishra, Pallavi; Dubey, R S

    2013-02-01

    The effects of increasing concentrations of nickel sulfate, NiSO(4) (200 and 400 μM) in the growth medium on the content of starch and sugars and activity levels of enzymes involved in starch and sugar metabolism were examined in seedlings of the two Indica rice cvs. Malviya-36 and Pant-12. During a 5-20 day growth period of seedlings in sand cultures, with Ni treatment, no definite pattern of alteration in starch level could be observed in the seedlings. In both roots and shoots of the seedlings Ni treatment led to a significant decrease in activities of starch degrading enzymes α-amylase, β-amylase, whereas starch phosphorylase activity increased. The contents of reducing, non-reducing, and total sugars increased in Ni-treated rice seedlings with a concomitant increase in the activities of sucrose degrading enzymes acid invertase and sucrose synthase. However, the activity of sucrose synthesizing enzyme sucrose phosphate synthase declined. These results suggest that Ni toxicity in rice seedlings causes marked perturbation in metabolism of carbohydrates leading to increased accumulation of soluble sugars. Such perturbation could serve as a limiting factor for growth of rice seedlings in Ni polluted environments and accumulating soluble sugars could serve as compatible solutes in the cells under Ni toxicity conditions.

  6. A widespread plant-fungal-bacterial symbiosis promotes plant biodiversity, plant nutrition and seedling recruitment.

    Science.gov (United States)

    van der Heijden, Marcel G A; de Bruin, Susanne; Luckerhoff, Ludo; van Logtestijn, Richard S P; Schlaeppi, Klaus

    2016-02-01

    Highly diverse microbial assemblages colonize plant roots. It is still poorly understood whether different members of this root microbiome act synergistically by supplying different services (for example, different limiting nutrients) to plants and plant communities. In order to test this, we manipulated the presence of two widespread plant root symbionts, arbuscular mycorrhizal fungi and nitrogen-fixing rhizobia bacteria in model grassland communities established in axenic microcosms. Here, we demonstrate that both symbionts complement each other resulting in increased plant diversity, enhanced seedling recruitment and improved nutrient acquisition compared with a single symbiont situation. Legume seedlings obtained up to 15-fold higher productivity if they formed an association with both symbionts, opposed to productivity they reached with only one symbiont. Our results reveal the importance of functional diversity of symbionts and demonstrate that different members of the root microbiome can complement each other in acquiring different limiting nutrients and in driving important ecosystem functions.

  7. Pathogenicity of P. terrestris on Maize Seedlings

    Directory of Open Access Journals (Sweden)

    Jelena Lević

    2012-01-01

    Full Text Available Pathogenicity of P. terrestris was determined by the Knop’s medium slants method intest tubes. Isolates originated from the roots of maize (Zea mays L., barley (Hordeum vulgareL., Johnson grass (Sorghum halepense Pers., sorghum (Sorghum bicolour (L. Moench., garlic(Allium sativum L., onion (Allium cepa L., barnyard millet (Echinochloa crus-galli (L. P.Beauv.and green foxtail (Setaria viridis (L. P.B.. A fragment of a fungal colony, cultivated on PDA,was placed on the bottom of Knop’s medium slant in each test tube and then steriliseda maize seed was placed 2 cm away from the inoculum. After 21-day inoculation of seeds,the intensity of the development of symptoms on maize seedlings was estimated. The reddishor dark pigment on the root, mesocotyl and/or coleoptyl of seedlings was an indicatorfor the infection by the fungus under in vitro conditions. Based on the pathogenicity test,the isolates were classified into the following three groups: slightly (3 isolates, moderately(6 isolates and very pathogenic (6 isolates to maize seedlings. The obtained results showthat P. terrestris, originating from different hosts, can be a maize pathogen. These resultscan explain the high frequency and high incidence of this fungus on maize roots in Serbia.

  8. Nutrient partitioning and seedling development in the genus Leucaena

    Energy Technology Data Exchange (ETDEWEB)

    Dovel, R.L.

    1987-01-01

    Slow establishment of the genus Leucaena from seed has been attributed to law seedling vigor and late nodulation. Observation of early seedling growth indicated that partitioning of a large proportion of resources to the root of young Leucaena seedlings could account, in part, for the slow initial shoot growth observed in this genus. Therefore, a series of experiments were conducted to examine the partitioning of stored seed reserves, photosynthate, and nitrogen in developing Leucaena seedlings. The effects of nodulation and nitrogen fertilization on partitioning of nutrients in the seedling were also examined. Seed reserves were initially used for radicle growth in dark grown seedlings; however, partitioning soon shifted to the hypocotyl. By four days after imbibition, hypocotyl weight exceeded radicle weight in both species tested (L. leucocephala and L. retusa), at all temperatures above 20/sup 0/C. Two experiments were conducted examining the carbon partitioning of L. leucocephala cultivar K-8 using /sup 14/CO/sub 2/ pulse labeling techniques.

  9. Propagation of Cucumber Seedlings in Different Organic and Inorganic Media

    Directory of Open Access Journals (Sweden)

    H. Cinkilİc

    2008-05-01

    Full Text Available The objective of this study is to investigate the possibility of using grape marc and cinder an alternative media to peat for cucumber propagation and find out the results.In the study;normal grape marc, normal grape marc+25% süper coarse perlite, ground grape marc+25% süper coarse perlite, cinder+25% süper coarse perlite, peat+25% süper coarse perlite and peat were used, the best results were obtained from grape marc + 25% super coarse perlite in stem diameter, number of true leaves, weight of seedling, width of seedling, length of leaves and width of leaves; from peat + 25% super coarse perlite in length of seedling, length of seedling with root, weight of root, weight of seedling with root and length of root. The cinder which is the residue of burned coal, gave the worst results in all seedling properties.

  10. Comparative performance of Moringa oleifera and Moringa ovalifolia seeds and seedlings establishment in central Namibia

    OpenAIRE

    Morlu Korsor; Charles Ntahonshikira; Habauka M. Kwaambwa; Haruna M. Bello

    2016-01-01

    Trees and shrubs can serve as fodder to supplement shortage of feeds for livestock particularly in arid and semi-arid environments where palatable grasses or browse plants could be limited due to low rainfall pattern and constant droughts. However, in Namibia Moringa tree species show the potential to curb shortage of feeds in livestock. A completely randomized design (CRD) was used in this study to compare the performance of M. ovalifolia and M. oleifera seed germination and seedlings establ...

  11. Growth and transpiration of Japanese cedar (Cryptomeria japonica) and Hinoki cypress (Chamaecyparis obtusa) seedlings in response to soil water content.

    Science.gov (United States)

    Nagakura, Junko; Shigenaga, Hidetoshi; Akama, Akio; Takahashi, Masamichi

    2004-11-01

    To investigate the effects of soil water content on growth and transpiration of Japanese cedar (Cryptomeria japonica D. Don) and Hinoki cypress (Chamaecyparis obtusa (Siebold et Zucc.) Endl.), potted seedlings were grown in well-watered soil (wet treatment) or in drying soil (dry treatment) for 12 weeks. Seedlings in the wet treatment were watered once every 2 or 3 days, whereas seedlings in the dry treatment were watered when soil water content (Theta; m3 m(-3)) reached 0.30, equivalent to a soil matric potential of -0.06 MPa. From Weeks 7 to 12 after the onset of the treatments, seedling transpiration was measured by weighing the potted seedlings. After the last watering, changes in transpiration rate during soil drying were monitored intensely. The dry treatment restricted aboveground growth but increased biomass allocation to the roots in both species, resulting in no significant treatment difference in whole-plant biomass production. The species showed similar responses in relative growth rate (RGR), net assimilation rate (NAR) and shoot mass ratio (SMR) to the dry treatment. Although NAR did not change significantly in either C. japonica or C. obtusa as the soil dried, the two species responded differently to the dry treatment in terms of mean transpiration rate (E) and water-use efficiency (WUE), which are parameters that relate to NAR. In the dry treatment, both E and WUE of C. japonica were stable, whereas in C. obtusa, E decreased and WUE increased (E and WUE counterbalanced to maintain a constant NAR). Transpiration rates were lower in C. obtusa seedlings than in C. japonica seedlings, even in well-watered conditions. During soil drying, the transpiration rate decreased after Theta reached about 0.38 (-0.003 MPa) in C. obtusa and 0.32 (-0.028 MPa) in C. japonica. We conclude that C. obtusa has more water-saving characteristics than C. japonica, particularly when water supply is limited.

  12. Longleaf pine bud development: influence of seedling nutrition

    Science.gov (United States)

    J. P. Barnett; D. P. Jackson; R. K. Dumroese

    2010-01-01

    A subset of seedlings from a larger study (Jackson and others 2006, 2007) were selected and evaluated for two growing seasons to relate bud development, and root-collar diameter (RCD), and height growth with three nursery fertilization rates. We chose seedlings in the 0.5 (lowest), 2.0 (mid-range), and 4.0 (highest) mg of nitrogen per seedling treatments. Buds moved...

  13. Containers of Attalea funifera fibers to produce eucalyptus seedlings

    OpenAIRE

    Andrea Vita Reis Mendonça; Lucas Gonçalves Ribeiro; José Roque Azevedo Assunção; Teresa Aparecida Soares de Freitas; Josival Santos Souza

    2016-01-01

    The aim of this study was to assess the technical feasibility of using biodegradable containers made of fiber waste of Attalea funifera Martius to produce seedling of Eucalyptus camaldulensis Dehnh. The work was carried out in three stages: manufacture of piassava fiber containers, seedling production and field simulation. The experiment of seedling production was in completely randomized design, with two treatments (polyethylene tube and biodegradable container) and 10 repetitions, with 64 s...

  14. Effects of carbon dioxide enrichment and nitrogen supply on growth of boreal tree seedlings.

    Science.gov (United States)

    Brown, Kevin; Higginbotham, K. O.

    1986-12-01

    The effects of two levels of atmospheric carbon dioxide (350 microl l(-1), 750 microl l(-1)) and three levels of nitrogen (15.5 mM, 1.55 mM, 0.155 mM N) on biomass accumulation and partitioning were examined in aspen (Populus tremuloides Michx.) and white spruce (Picea glauca (Moench) Voss) seedlings grown in controlled environment rooms for 100 days after germination. Nitrogen supply had pronounced effects on biomass accumulation, height, and leaf area of both species. Root weight ratio (RWR) of white spruce was significantly increased at the lowest level of nitrogen, whereas RWR of aspen did not change much with increasing levels of nitrogen. Carbon dioxide enrichment significantly increased (1) the leaf and total biomass of spruce seedlings grown in the high-N regime, (2) the RWR of seedlings in the medium-N regime, and (3) the root biomass of seedlings in the low-N regime after 100 days. Carbon dioxide enrichment of aspen temporarily increased biomass and height in all three nitrogen regimes. Root, stem, and leaf mass, height, and leaf area of aspen were increased only at the 30-day harvest in the high-N treatment and at 50 and 60 days in the low-N treatment. Height, stem biomass, and leaf biomass of aspen seedlings were significantly increased by CO(2) enrichment after 40 days in the medium-N treatment. These effects did not persist, possibly because of the onset of mineral nutrient supply limitations with increasing plant size.

  15. Can a genetic correlation with seed mass constrain adaptive evolution of seedling desiccation tolerance in wild barley?

    NARCIS (Netherlands)

    Verhoeven, K.J.F.; Biere, A.; Nevo, E.; Van Damme, J.M.M.

    2004-01-01

    Very young seedlings of wild barley Hordeum spontaneum have the ability to survive extended periods of severe drought. This desiccation tolerance is considered an adaptation to the rain-limited and unpredictable habitats that the species occupies. Genetic variation has been observed for this trait,

  16. Can a genetic correlation with seed mass constrain adaptive evolution of seedling desiccation tolerance in wild barley?

    NARCIS (Netherlands)

    Verhoeven, K.J.F.; Biere, A.; Nevo, E.; Van Damme, J.M.M.

    2004-01-01

    Very young seedlings of wild barley Hordeum spontaneum have the ability to survive extended periods of severe drought. This desiccation tolerance is considered an adaptation to the rain-limited and unpredictable habitats that the species occupies. Genetic variation has been observed for this trait,

  17. Genetic architecture of cold tolerance in rice at the seedling stage and heading determined through genome-wide association studies

    Science.gov (United States)

    Cold stress at the seedling stage limits rice (Oryza sativa L.) production in temperate regions or at high elevations in the tropics due to poor plant stand establishment and delayed maturity. At the heading stage, cold temperature causes sterility, thus decreasing grain yield. Initially, the Rice D...

  18. Influence of enhanced UV-B radiation on the chloroplast pigments and photosynthesis rate in cucumber seedlings

    Directory of Open Access Journals (Sweden)

    Magdalena Rybus-Zając

    2012-09-01

    Full Text Available The effect of increased UV-B radiation (16 kJ/m2 per day on the level of chloroplast pigments and rate of photosynthesis and growth of seedlings of cucumber in two stages was examined. In the cotyledons subjected to UV-B radiation content of chloroplast pigments and photosynthesis rate was higher than in controls. In the leaves of 3-week-old seedlings increased UV-B radiation limited chloroplast pigments level, intensity photosynthesis and growth.  

  19. Seed germination, seedling traits, and seed bank of the tree Moringa peregrina (Moringaceae) in a hyper-arid environment.

    Science.gov (United States)

    Gomaa, Nasr H; Picó, F Xavier

    2011-06-01

    Water-limited hot environments are good examples of hyper-aridity. Trees are scarce in these environments but some manage to survive, such as the tree Moringa peregrina. Understanding how trees maintain viable populations in extremely arid environments may provide insight into the adaptive mechanisms by which trees cope with extremely arid weather conditions. This understanding is relevant to the current increasing aridity in several regions of the world. Seed germination experiments were conducted to assess variation in seed mass, seed germination, and seedling traits of Moringa peregrina plants and the correlations among these traits. A seed burial experiment was also designed to study the fate of M. peregrina seeds buried at two depths in the soil for two time periods. On average, seeds germinated in three days and seedling shoots grew 0.7 cm per day over three weeks. Larger seeds decreased germination time and increased seedling growth rates relative to smaller seeds. Seeds remained quiescent in the soil and germination was very high at both depths and burial times. The after-ripening time of Moringa peregrina seeds is short and seeds germinate quickly after imbibition. Plants of M. peregrina may increase in hyper-arid environments from seeds with larger mass, shorter germination times, and faster seedling growth rates. The results also illustrate the adjustment in allocation to seed biomass and correlations among seed and seedling traits that allows M. peregrina to be successful in coping with aridity in its environment.

  20. Expression Patterns of Glutathione Transferase Gene (GstI in Maize Seedlings Under Juglone-Induced Oxidative Stress

    Directory of Open Access Journals (Sweden)

    Hubert Sytykiewicz

    2011-11-01

    Full Text Available Juglone (5-hydroxy-1,4-naphthoquinone has been identified in organs of many plant species within Juglandaceae family. This secondary metabolite is considered as a highly bioactive substance that functions as direct oxidant stimulating the production of reactive oxygen species (ROS in acceptor plants. Glutathione transferases (GSTs, E.C.2.5.1.18 represent an important group of cytoprotective enzymes participating in detoxification of xenobiotics and limiting oxidative damages of cellular macromolecules. The purpose of this study was to investigate the impact of tested allelochemical on growth and development of maize (Zea mays L. seedlings. Furthermore, the effect of juglone-induced oxidative stress on glutathione transferase (GstI gene expression patterns in maize seedlings was recorded. It was revealed that 4-day juglone treatment significantly stimulated the transcriptional activity of GstI in maize seedlings compared to control plants. By contrast, at the 6th and 8th day of experiments the expression gene responses were slightly lower as compared with non-stressed seedlings. Additionally, the specific gene expression profiles, as well as the inhibition of primary roots and coleoptile elongation were proportional to juglone concentrations. In conclusion, the results provide strong molecular evidence that allelopathic influence of juglone on growth and development of maize seedlings may be relevant with an induction of oxidative stress in acceptor plants.

  1. Embryo Incision as a New Technique for Double Seedling Production of Indonesian Elite Coconut Type “Kopyor”

    Directory of Open Access Journals (Sweden)

    Sisunandar

    2015-12-01

    Full Text Available One of the present major limitations of seedling production of kopyor type coconut using embryo culture is that only one seedling can be produced from a single embryo. Therefore, we report on the development of a new breakthrough technique for the production of double seedlings from a single embryo. The technique consists of four steps, viz. (i germination; (ii incision; (iii splitting; and (iv recovery. A histological study was carried out on the development of the halved embryo into a new shoot. The best recovery process was obtained when the incised embryo was split into two and recovered into Murashige and Skoog (MS medium supplemented with 2 μM IBA and 15 μM kinetin. Following this protocol, an average of 56 shoots was successfully recovered from 30 zygotic embryos. The histological study also revealed that the meristem tissue of the halved embryo was able to produce a new meristem and primordial leaf. Most of the shoots then went on to produce normal seedlings and could be acclimatized successfully after having developed 2 or 3 leaves. This protocol is useful for routine seedling production of the kopyor-type coconut.

  2. Control of seedling blight in winter wheat by seed treatments - impact on emergence, crop stand, yield and deoxynivalenol

    DEFF Research Database (Denmark)

    Jørgensen, Lise N; K. Nielsen, Linda; Nielsen, Bent J

    2012-01-01

    Seedling blight caused by Fusarium spp. and Microdochium spp. is common on wheat grain, and severe attacks can lead to poor establishment of new crops. Several seed treatments using bitertanol, difenoconazole, triticonazole, maneb, fludioxonil or guazatine found to significantly control Fusarium...... seedling blight (Fusarium spp., Microdochium spp.) were improving germination and reducing seedling blight on roots and coleoptiles under field conditions in winter wheat. Some of the seed treatments were also shown to have an impact on soil-borne Fusarium in trials carried out under glasshouse conditions...... germination by approximately 100%, which led to an improved crop stand and yield increases in the range of 1.2–1.5 tonnes ha−1. Attacks of Fusarium head blight were relatively slight in the two trials and the content of deoxynivalenol was below the EU limits of 1250 ppb in the harvested grain. Even so, seed...

  3. Habitat-related variation in seedling recruitment of Gentiana pannonica

    Science.gov (United States)

    Ekrtová, Ester; Košnar, Jan

    2012-11-01

    Differences in seedling recruitment of Gentiana pannonica were investigated between the primary (relict) and the secondary (semi-natural) forest-free habitats of the Bohemian Forest (870-1200 m a.s.l.) and of the Alps (1045-1935 m a.s.l.) to understand the factors promoting the seedling recruitment of G. pannonica and their importance for species distribution, population structure, and conservation. In the communities with adult plants of G. pannonica, we recorded environmental variables (the slope, the altitude, and the covers of bare ground, litter, and rocks), estimated parameters of the vegetation (the covers of herbs, bryophytes, and dwarf shrubs), and counted the seedlings of G. pannonica. In a field experiment, we investigated seedling survival under different soil moisture regimes. We also observed seasonal dynamics of seedling recruitment in permanent plots over the course of three years. In the primary habitats of both regions, G. pannonica grew in a relatively wide range of communities, and its seedlings occurred in each area. In the secondary habitats of the Bohemian Forest, a very low frequency of the seedlings was recorded. The number of seedlings increased with the covers of the moss layer and of bare soil and decreased with the cover of the herb layer, especially of graminoids. The seedling mortality was significantly lower in the plots with higher soil moistures, and the emergence of new-born seedlings was concentrated in the spring season, when the soil received a high water supply due to melting of snow. For the successful generative reproduction of G. pannonica, our findings highlight the critical importance of the microsites with low levels of competition and of sufficient soil moisture G. pannonica. It seems that because of the long-term lack of grazing disturbances, the structures of the secondary habitats of G. pannonica in the Bohemian Forest have become unfavourable for seedling establishment and generative reproduction of this threatened

  4. Seedling transplants reveal species-specific responses of high-elevation tropical treeline trees to climate change.

    Science.gov (United States)

    Rehm, Evan M; Feeley, Kenneth J

    2016-08-01

    The elevations at which tropical treelines occur are believed to represent the point where low mean temperatures limit the growth of upright woody trees. Consequently, tropical treelines are predicted to shift to higher elevations with global warming. However, treelines throughout the tropics have remained stationary despite increasing global mean temperatures. The goal of the study reported here was to build a more comprehensive understanding of the effects of mean temperature, low-temperature extremes, shading, and their interactions on seedling survival at tropical treelines. We conducted a seedling transplant study using three dominant canopy-forming treeline species in the southern tropical Andes. We found species-specific differences and contrasting responses in seedling survival to changes in mean temperature. The most abundant naturally occurring species at the seedling stage outside the treeline, Weinmannia fagaroides, showed a negative relationship between the survival of transplanted seedlings and mean temperature, the opposite of a priori expectations. Conversely, Clethra cuneata showed increased survival at higher mean temperatures, but survival also increased with higher absolute low temperatures and the presence of shade. Finally, the survival of Gynoxys nitida seedlings was insensitive to temperature but increased under shade. These findings show that multiple factors can determine the upper distributional limit of species forming the current tropical treeline. As such, predictions of future local and regional tropical treeline shifts may need to consider several factors beyond changes in mean temperature. If the treeline remains stationary and cloud forests are unable to expand into higher elevations, there may be severe species loss in this biodiversity hotspot.

  5. Relative importance of various regeneration mechanisms in different restoration stages of Quercus variabilis forest after selective logging

    Directory of Open Access Journals (Sweden)

    Yaoqin Xue

    2014-08-01

    Full Text Available Aim of study: Quercus variabilis (Chinese cork oak reproduces asexually and sexually. This study aimed to determine the status and growth of asexual and sexual recruits of Q. variabilis in different forest recovery stages.Area of study: Three selective logged stands and one unlogged stand in Q. variabilis forest, Shaanxi Province, China.Material and Methods: Origin, number, basal diameter, height and size structure of Q. variabilis shoots (height ≤200 cm were investigated in the plots of 5, 10, and 20-years post-logging stands and unlogged stand. Effects of recovery stage on the density and growth of the three original recruits (stump sprouts, stem base sprouts and true seedlings were analysis by One-way ANOVA.Main results: Sprouts dominated logged stands, whereas true seedlings dominated unlogged stand, stem base sprouts only existed in 20-years post-logging and unlogged stands. Stump sprout density and sprout number per stump both declined with extended post-logging time. True seedlings density increased from 7 to 20 shoots/100 m2 as the postlogging time extended, and peaked in unlogged stand (94 shoots/100 m2. An ongoing size structure was observed in true seedlings in all stands. Stump sprouts were taller and greater than true seedlings.Research highlights: Stump sprouts contributed more to Q. variabilis forest recovery in the early stage after disturbance. The contribution of true seedlings was limited in the same stage, but they were beneficial for population long-term development. Stem base sprouts were most likely to be a survival strategy rather than a reproductive strategy.Key words: asexual reproduction; true seedling; post-logging time; Chinese cork oak.

  6. Seedling Growth and Phosphorus Cycling in Northern Forest Soils Amended With Biochar and Wood Ash

    Science.gov (United States)

    Noyce, G. L.; Jones, T.; Fulthorpe, R.; Basiliko, N.

    2015-12-01

    Biochar may be a powerful soil amendment to reduce nutrient depletion in North American forests where long-term nitrogen deposition has led to phosphorus (P) limitation, but many effects of biochar in these ecosystems are still unknown. We performed a 12-week growth chamber experiment in which red pine (Pinus resinosa) and sugar maple (Acer saccharum) seedlings were grown in pots with soil from three Ontario forests and varying amounts of sugar maple biochar. Additionally, biochar effects were compared with the effects of wood ash, a forest biomass bioenergy by-product that may also be a beneficial soil amendment in these ecosystems. We assessed plant biomass, soil microbial biomass and phosphatase activity; additional chemical analyses of plant tissue and soils are ongoing. Biochar effects on seedling growth were not consistent across tree species, soil type, and addition rate. For sugar maple seedlings grown in sand and sandy-loam textured soils, biochar additions of 20 t ha-1 significantly (p = 0.03) decreased root biomass by 25 %, and the root-to-shoot ratio correspondingly declined, but this effect was not observed in a silty soil. For red pine seedlings, the same biochar addition rate slightly increased root biomass. Wood ash effects on biomass were similarly variable. For example, in the sandy soil, sugar maple root biomass was significantly lower after application of 16 t ash ha-1, but unchanged by rates of 4 or 40 t ash ha-1. Microbial biomass and soil phosphatase activity also varied by soil type. Phosphatase activity was significantly lower (p = 0.02) in soils with sugar maple compared to red pine, but there were no consistent biochar or ash effects across all soils and species. However, for red pine seedlings grown in silt, biochar significantly (p = 0.04) reduced the phosphatase activity compared to the control and ash soils. Overall, biochar may lessen P-limitation in forested ecosystems, but the suitability of biochar, and wood ash, for increasing P

  7. Quality of tomato seedling in application bioproducts

    OpenAIRE

    BOTEVA, Hriska

    2014-01-01

    The study was performed during the period 2009 - 2011 in the “Maritsa” Vegetable Crops Research Institute, Plovdiv. The effect of organic products Baikal EM – 1У, Bioglobin and Biolan on the quality of seedlings from tomato, variety Yana was studied in unheated glasshouses ro-ON type. Plants were grown on two substrates: peat-perlite substrate and substrate with Lumbrikal. The post-effect of the applied bioproducts on the plant productivity was studied in field conditions. Tomato seeds from Y...

  8. Radiation effects on Brassica seeds and seedlings

    Science.gov (United States)

    Deoli, Naresh; Hasenstein, Karl H.

    2016-07-01

    Space radiation consists of high energy charged particles and affects biological systems, but because of its stochastic, non-directional nature is difficult to replicate on Earth. Radiation damages biological systems acutely at high doses or cumulatively at low doses through progressive changes in DNA organization. These damages lead to death or cause of mutations. While radiation biology typically focuses on mammalian or human systems, little is known as to how radiation affects plants. In addition, energetic ion beams are widely used to generate new mutants in plants considering their high-LET (Linear Energy Transfer) as compared to gamma rays and X-rays. Understanding the effect of ionizing radiation on plant provides a basis for studying effects of radiation on biological systems and will help mitigate (space) radiation damage in plants. We exposed dry and imbibed Brassica rapa seeds and seedling roots to proton beams of varying qualities and compared the theoretical penetration range of different energy levels with observable growth response. We used 1, 2 and 3 MeV protons in air at the varying fluences to investigate the effect of direct irradiation on the seeds (1012 - 1015 ions/cm2) and seedlings (1013 ions/cm2). The range of protons in the tissue was calculated using Monte-Carlo based SRIM (Stopping and Range of Ions in Matter) software. The simulation and biological results indicate that ions did not penetrate the tissue of dry or hydrated seeds at all used ion energies. Therefore the entire energy was transferred to the treated tissue. Irradiated seeds were germinated vertically under dim light and roots growth was observed for two days after imbibition. The LD50 of the germination was about 2×1014 ions/cm2 and about 5×1014 ions/cm2 for imbibed and dry seeds, respectively. Since seedlings are most sensitive to gravity, the change in gravitropic behavior is a convenient means to assess radiation damage on physiological responses other than direct tissue

  9. Characterization of nutrient deficiency in Hancornia speciosa Gomes seedlings by omitting micronutrients from the nutrient solution

    Directory of Open Access Journals (Sweden)

    Layara Alexandre Bessa

    2013-06-01

    Full Text Available Hancornia speciosa Gomes (Mangaba tree is a fruit tree belonging to the Apocynaceae family and is native to Brazil. The production of seedlings of this species is limited by a lack of technical and nutritional expertise. To address this deficiency, this study aimed to characterize the visual symptoms of micronutrient deficiency and to assess growth and leaf nutrient accumulation in H. speciosa seedlings supplied with nutrient solutions that lack individual micronutrients. H. speciosa plants were grown in nutrient solution in a greenhouse according to a randomized block design, with four replicates. The treatments consisted of a group receiving complete nutrient solution and groups treated with a nutrient solution lacking one of the following micronutrients: boron (B, copper (Cu, iron (Fe, manganese (Mn, zinc (Zn, and molybdenum (Mo. The visual symptoms of nutrient deficiency were generally easy to characterize. Dry matter production was affected by the omission of micronutrients, and the treatment lacking Fe most limited the stem length, stem diameter, root length, and number of leaves in H. speciosa seedlings as well as the dry weight of leaves, the total dry weight, and the relative growth in H. speciosa plants. The micronutrient contents of H. speciosa leaves from plants receiving the complete nutrient solution treatment were, in decreasing order, Fe>Mn>Cu>Zn>B.

  10. Evaluation of Promalin to promote growth of young mangosteen seedlings

    Science.gov (United States)

    A major impediment to the development of a mangosteen (Garcinia mangostana L.) industry is the long pre-bearing stage that seedlings take to produce fruits. A field study was conducted to determine the effect of Promalin on the growth of mangosteen seedlings. Promalin was applied as a foliar spray...

  11. Fusarium resistance in Gladiolus: selection in seedling populations

    NARCIS (Netherlands)

    Straathof, Th.P.; Jansen, J.; Roebroeck, E.J.A.; Löffler, H.J.M.

    1997-01-01

    A test to select Fusarium resistant seedlings of Gladiolus is described. Seedlings of 37 populations, obtained from an incomplete diallel between eight parents with different levels of Fusarium resistance, were used. Significant differences in Fusarium infection between and within populations were d

  12. Coumarin pretreatment alleviates salinity stress in wheat seedlings.

    Science.gov (United States)

    Saleh, Ahmed Mahmoud; Madany, M M Y

    2015-03-01

    The potentiality of COU to improve plant tolerance to salinity was investigated. Wheat grains were primed with COU (50 ppm) and then grown under different levels of NaCl (50, 100, 150 mM) for two weeks. COU pretreatment improved the growth of wheat seedling under salinity, relative to COU-untreated seedlings, due to the accumulation of osmolytes such as soluble sugars and proline. Moreover, COU treatment significantly improved K(+)/Na(+) ratio in the shoots of both salt stressed and un-stressed seedlings. However, in the roots, this ratio increased only under non-salinity. In consistent with phenylalanine ammonia lyase (PAL), phenolics and flavonoids were accumulated in COU-pretreated seedlings under the higher doses of salinity, relative to COU-untreated seedlings. COU primed seedlings showed higher content of the coumarin derivative, scopoletin, and salicylic, chlorogenic, syringic, vanillic, gallic and ferulic acids, under both salinity and non-salinity conditions. Salinity stress significantly improved the activity of peroxidase (POD) in COU-pretreated seedlings. However, the effect of COU on the total antioxidant capacity (TAC) was only obtained at the highest dose of NaCl (150 mM). The present results suggest that COU pretreatment could alleviate the adverse effect of salinity on the growth of wheat seedlings through enhancing, at least partly, the osmoregulation process and antioxidant defense system.

  13. Photoreceptive sites in the photocontrol of oat seedling growth

    Directory of Open Access Journals (Sweden)

    Kazimierz Madela

    2014-01-01

    Full Text Available The influence of red light on the growth of coleoptiles and mesocotyles of etiolated and pre-irradiated oat seedlings was investigated. Red light (15 min. applied on whole seedlings stimulated the elongation of coleoptiles and inhibited the growth of mesocotyles both in etiolated and in pre-irradiated plants. Irradiation with red light (2 min of various 2-mm-long regions of etiolated and pre-irradiated oat seedlings was carried out in order to locate their light reception regions. On the basis of growth reactions after such treatment it was found that in completely etiolated seedlings the light reception sites involved in the stimulation of coleoptile elongation and inhibition of mesocotyle growth lie directly above and below the seedling node, whereas in pre-irradiated seedlings, in the top of the seedling. These results point to the existence of different growth photoregulation systems in etiolated and pre-irradiated oat seedlings. The role of phytochrome in these phenomena is discussed.

  14. Control damage by seedling debarking weevil. Technical note No. 271

    Energy Technology Data Exchange (ETDEWEB)

    Eidt, D.C.; Weaver, C.A.A.

    1993-01-01

    Technical note describing a method of controlling the damage to seedlings by the seedling debarking weevil by using nematodes. Information is given on the damage involved, the nematodes to be used, treatment methods, planting procedures, benefits and costs, and results of earlier trials.

  15. Provenances and fertilizer on early growth cedar seedlings

    Directory of Open Access Journals (Sweden)

    Marcio Carlos Navroski

    2016-03-01

    Full Text Available The aim of the study was to evaluate the initial development of different provenances and the influence of base fertilizer and coverage on growth of Cedrela fissilis seedlings. Provenances of seeds were collected in Lapa, PR, Fernandes Pinheiro, PR and Itaara, RS. After germination, the seedlings were transplanted to plastic bags of 500 cm³, filled with commercial substrate. Total height (h, stem diameter (sd, and ratio h/sd seedlings were measured after 150 days of transplanting. Seedlings of Fernandes Pinheiro received basic fertilization after transplantation (0, 2, 4, 6 and 8 g dm-3  Osmocote® and cover (3 and 6 g L-1, respectively, of Peter’s® and urea. The provenance and doses of controlled-release fertilizer influenced early development of Cedrela fissilis seedlings. Itaara provenance showed better seedlings growth. Cedar seedlings showed good growth when incorporated into the substrate 5 g dm-3 Osmocote® and, in addition, applied in topdressing 3 g L-1 of Peter’s®. Urea topdressing is rarely recommended for cedar seedlings.

  16. Carbohydrate accumulation in the needles of Siberian stone pine seedlings

    Directory of Open Access Journals (Sweden)

    A. Panov

    2013-12-01

    Full Text Available The aim of the research presented is to study effects extracted from biologically active peat substances on carbohydrate accumulationprocesses. The study was carried out on 5-year-old Siberian stone pine seedlings grown in the nursery forest in the southern part of the Tomsk region. These seedlings were treated with a peat preparation, which was created in Tomsk. Four groups of experimental plants were organized on the analog principle. Each group consisted of 30 seedlings of average size and half of these seedlings were control. At the beginning of the vegetative season, a single treatment was applied to experimental plants with water solution peat preparation. The first group of plants was treated with a 0.1% solution; the dose was calculated by dry substance. For the second group, the dose was increased by 25%. For the third and fourth groups, the dose was decreased by 25% relative to the first group. Control plants were sprayed with water. Accumulation of carbohydrates and pigments as well as growth values in the 2-year- old needles were studied by standard methods. Glucose levels in the experimental plants existed within the limits 117-120%. On the whole, simple sugar quantity did not differs between experimental variants.Glucose synthesis was accompanied by changes in quantitative values of fructose. This, connected with glucose being a more stable compound, and compulsory conversion from glucose to labile form fructose was necessary. The amount of fructose in the experimental seedlings had a very wide range. This process was accompanied by shoot elongationin Siberian stone pine in the first year after treatment, with the fructose amount of 14% exceeding control values in the first and fourth group. Shoot growth was accompanied by increased fructose amount to 20% relative to control. A similar situation was observed afterwinter with respect to buds. Experimental plants dominated by number of buds

  17. Evolutionary history and distance dependence control survival of dipterocarp seedlings.

    Science.gov (United States)

    Bagchi, Robert; Press, Malcolm C; Scholes, Julie D

    2010-01-01

    One important hypothesis to explain tree-species coexistence in tropical forests suggests that increased attack by natural enemies near conspecific trees gives locally rare species a competitive advantage. Host ranges of natural enemies generally encompass several closely related plant taxa suggesting that seedlings should also do poorly around adults of closely related species. We investigated the effects of adult Parashorea malaanonan on seedling survival in a Bornean rain forest. Survival of P. malaanonan seedlings was highest at intermediate distances from parent trees while heterospecific seedlings were unaffected by distance. Leaf herbivores did not drive this relationship. Survival of seedlings was lowest for P. malaanonan, and increased with phylogenetic dissimilarity from this species, suggesting that survival of close relatives of common species is reduced. This study suggests that distance dependence contributes to species coexistence and highlights the need for further investigation into the role of shared plant enemies in community dynamics.

  18. Analysis on Factors Affecting Seedling Establishment in Rice

    Directory of Open Access Journals (Sweden)

    Ju LUO

    2007-03-01

    Full Text Available Elongations of coleoptile and mesocotyl are related directly to rice seedling establishment in soil and height of plant is related to lodging in rice production. Twelve typical rice cultivars with different lengths of coleoptile and mesocotyl (long, medium and short were selected by screening the lengths of coleoptile and mesocotyl in 1500 accessions. The seedling establishments of these typical cultivars were compared under the combinations of different sowing depths and flooding durations, and two semi-dwarf varieties (G140, Zhong 96–21 with good seedling establishments and optimum mesocotyl lengths were found. The length of mesocotyl was completely fitted negative binomial distribution and the length of coleoptile was nearly fitted lognormal distribution. Analysis of the relationships among mesocotyl, coleoptile, seeding depth, flooding duration, and their interactions to seedling establishment percentage showed that there existed significant relations among mesocotyl, coleoptile, mesocotyl × coleoptile, seeding depth, flooding duration and mesocotyl × sowing depth in the experiment for seedling establishment.

  19. Analysis on Factors Affecting Seedling Establishment in Rice

    Institute of Scientific and Technical Information of China (English)

    LUO Ju; TANG Shao-qing; HU Pei-song; Aleman LOUIS; JIAO Gui-ai; TANG Jian

    2007-01-01

    Elongations of coleoptile and mesocotyl are related directly to rice seedling establishment in soil and height of plant is related to lodging in rice production. Twelve typical rice cultivars with different lengths of coleoptile and mesocotyl (long, medium and short) were selected by screening the lengths of coleoptile and mesocotyl in 1500 accessions. The seedling establishments of these typical cultivars were compared under the combinations of different sowing depths and flooding durations, and two semi-dwarf varieties (G140, Zhong 96-21) with good seedling establishments and optimum mesocotyl lengths were found. The length of mesocotyl was completely fitted negative binomial distribution and the length of coleoptile was nearly fitted Iognormal distribution.Analysis of the relationships among mesocotyl, coleoptile, seeding depth, flooding duration, and their interactions to seedling establishment percentage showed that there existed significant relations among mesocotyl, coleoptile, mesocotyl × coleoptile,seeding depth, flooding duration and mesocotyl × sowing depth in the experiment for seedling establishment.

  20. Effects of graphene on seed germination and seedling growth

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Ming; Gao, Bin, E-mail: bg55@ufl.edu [University of Florida, Department of Agricultural and Biological Engineering (United States); Chen, Jianjun [University of Florida, Department of Environmental Horticulture and Mid-Florida Research & Education Center (United States); Li, Yuncong [University of Florida, Soil and Water Science Department Tropical Research & Education Center (United States)

    2015-02-15

    The environmental impact of graphene has recently attracted great attention. In this work, we show that graphene at a low concentration affected tomato seed germination and seedling growth. Graphene-treated seeds germinated much faster than control seeds. Analytical results indicated that graphene penetrated seed husks. The penetration might break the husks to facilitate water uptake, resulting in faster germination and higher germination rates. At the stage of seedling growth, graphene was also able to penetrate root tip cells. Seedlings germinated from graphene-treated seeds had slightly lower biomass accumulation than the control, but exhibited significantly longer stems and roots than the control, which suggests that graphene, in contrast with other nanoparticles, had different effects on seedling growth. Taken together, our results imply that graphene played complicated roles in affecting the initial stage of seed germination and subsequent seedling growth.

  1. Climate and soil factors influencing seedling recruitment of plant species used for dryland restoration

    Science.gov (United States)

    Muñoz-Rojas, Miriam; Erickson, Todd E.; Martini, Dylan C.; Dixon, Kingsley W.; Merritt, David J.

    2016-06-01

    Land degradation affects 10-20 % of drylands globally. Intensive land use and management, large-scale disturbances such as extractive operations, and global climate change, have contributed to degradation of these systems worldwide. Restoring these damaged environments is critical to improving ecosystem services and functions, conserve biodiversity, and contribute to climate resilience, food security, and landscape sustainability. Here, we present a case study on plant species of the mining intensive semi-arid Pilbara region in Western Australia that examines the effects of climate and soil factors on the restoration of drylands. We analysed the effects of a range of rainfall and temperature scenarios and the use of alternative soil materials on seedling recruitment of key native plant species from this area. Experimental studies were conducted in controlled environment facilities where conditions simulated those found in the Pilbara. Soil from topsoil (T) stockpiles and waste materials (W) from an active mine site were mixed at different proportions (100 % T, 100 % W, and two mixes of topsoil and waste at 50 : 50 and 25 : 75 ratios) and used as growth media. Our results showed that seedling recruitment was highly dependent on soil moisture and emergence was generally higher in the topsoil, which had the highest available water content. In general, responses to the climate scenarios differed significantly among the native species which suggest that future climate scenarios of increasing drought might affect not only seedling recruitment but also diversity and structure of native plant communities. The use of waste materials from mining operations as growth media could be an alternative to the limited topsoil. However, in the early stages of plant establishment successful seedling recruitment can be challenging in the absence of water. These limitations could be overcome by using soil amendments but the cost associated to these solutions at large landscape scales

  2. Effects of carbon dioxide concentration and nutrition on photosynthetic functions of white birch seedlings

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, S. [Lakehead Univ., Thunder Bay, ON (Canada). Faculty of Forestry and the Forest Environment; Dang, Q.L. [Lakehead Univ., Thunder Bay, ON (Canada). Faculty of Forest and the Forest Environment; Chinese Academy of Sciences, Beijing (China). Inst. of Botany, Laboratory of Quantitative Vegetation Ecology

    2006-11-15

    Increases in atmospheric carbon dioxide (CO{sub 2}) can impact photosynthesis and dry mass production of plants. This study investigated the physiological responses of white birch seedlings to elevated carbon dioxide (CO{sub 2}) at low and high supplies of nitrogen (N), phosphorus (P) and potassium (K). A 2-way factorial experiment was carried out with birch seedlings grown for 4 months in environment-controlled greenhouses. Elevated CO{sub 2} enhanced maximal carboxylation rate and photosynthetically active radiation-saturated electron transport rates were measured after 2.5 and 3.5 months of treatment, as well as actual photochemical efficiency and photosynthetic linear electron transport to carboxylation. Net photosynthetic rate increases were observed as well as increases in photosynthetic water use efficiency (WUE); photosynthetic N efficiency and P efficiency. Stomatal conductance, transpiration rate and the fraction of total photosynthetic linear electron transport partitioned to oxygenation were reduced. Low nutrient availability decreased net photosynthetic rates, WUE, and triose phosphate utilization. However, photosynthetic linear electron transport and N use efficiency increased. There were significant interactive effects of CO{sub 2} and nutrition over time, with evidence of photosynthetic up-regulation in response to elevated CO{sub 2} in seedlings receiving high nutrition. Photosynthetic depression in response to low nutrient availability was attributed to biochemical limitation rather than stomatal limitation. Elevated CO{sub 2} reduced leaf N concentration in seedlings receiving low nutrition, but had no significant effect on leaf P or K concentrations. High nutrient availability generally increased area-based leaf N, P and K concentrations but had negligible effects on K after 2.5 months of treatment. Results suggested that increases in electron partitioning to photorespiration in response to low nutrient availability may be related to

  3. Seedling growth responses to soil resources in the understory of a wet tropical forest.

    Science.gov (United States)

    Holste, Ellen K; Kobe, Richard K; Vriesendorp, Corine F

    2011-09-01

    Plant growth responses to resources may be an important mechanism that influences species' distributions, coexistence, and community structure. Irradiance is considered the most important resource for seedling growth in the understory of wet tropical forests, but multiple soil nutrients and species have yet to be examined simultaneously with irradiance under field conditions. To identify potentially limiting resources, we modeled tree seedling growth as a function of irradiance and soil nutrients across five sites, spanning a soil fertility gradient in old-growth, wet tropical forests at La Selva Biological Station, Costa Rica. We measured an array of soil nutrients including total nitrogen (total N), inorganic N (nitrate [NO3-] and ammonium [NH4+]), phosphate (PO4-), and sum of base cations (SBC; potassium, magnesium, and calcium). Shade in the forest understory did not preclude seedling growth correlations with soil nutrients. Irradiance was a significant predictor of growth in 52% of the species, inorganic N in 54% (NO3- in 32%; NH4+ in 34%), total N in 47%, SBC in 39%, and PO4- in 29%. Overall, growth was correlated with both irradiance and soil nutrients in 45% of species and with soil nutrients only in an additional 48%; rarely was irradiance alone correlated with growth. Contrary to expectations, the magnitudes of growth effects, assessed as the maximum growth response to significant resources for each species, were similar for irradiance and most soil nutrients. Among species whose growth correlated with soil nutrients, the rank importance of nutrient effects was SBC, followed by N (total N, NO3-, and/or NH4+) and PO4-. Species' growth responsiveness (i.e., magnitudes of effect) to irradiance and soil nutrients was negatively correlated with species' shade tolerance (survival under 1% full sun). In this broad survey of species and resources, the nearly ubiquitous effects of soil nutrients on seedling growth challenge the idea that soil nutrients are less

  4. Screening cotton genotypes for seedling drought tolerance

    Directory of Open Access Journals (Sweden)

    Penna Julio C. Viglioni

    1998-01-01

    Full Text Available The objectives of this study were to adapt a screening method previously used to assess seedling drought tolerance in cereals for use in cotton (Gossypium hirsutum L. and to identify tolerant accessions among a wide range of genotypes. Ninety genotypes were screened in seven growth chamber experiments. Fifteen-day-old seedlings were subjected to four 4-day drought cycles, and plant survival was evaluated after each cycle. Three cycles are probably the minimum required in cotton work. Significant differences (at the 0.05 level or lower among entries were obtained in four of the seven experiments. A "confirmation test" with entries previously evaluated as "tolerant" (high survival and "susceptible" (low survival was run. A number of entries duplicated their earlier performance, but others did not, which indicates the need to reevaluate selections. Germplasms considered tolerant included: `IAC-13-1', `IAC-RM4-SM5', `Minas Sertaneja', `Acala 1517E-1' and `4521'. In general, the technique is simple, though time-consuming, with practical value for screening a large number of genotypes. Results from the screening tests generally agreed with field information. The screening procedure is suitable to select tolerant accessions from among a large number of entries in germplasm collections as a preliminary step in breeding for drought tolerance. This research also demonstrated the need to characterize the internal lack of uniformity in growth chambers to allow for adequate designs of experiments.

  5. Accelerating Seed Germination and seedling development of Sorghum (Sorghum bicolor L. Moench) through hydro-priming

    Science.gov (United States)

    Dembele, S., Jr.

    2015-12-01

    Mali, a West Africa Sahelian country, is characterized by a strong dependence on rain-fed agriculture and a low adaptive capacity, making it one of the most vulnerable regions to climate change worldwide. Moreover, although with high uncertainties, most climate models used for the region recognize a growing uncertainty in the onset of the rainy season, which demands urgent adaptation measures. Early-season drought limits crops germination, and hence growth, and yield during rainfed depending production as is common now in Mali, West Africa. Crops germination and establishment could be improved by using seed priming, a process that dry seeds take up water to initiate the primary stages of germination, but the amount of water added is not enough for completing germination. The effects of hydro-priming (distilled, tap, rain, river and well water) were evaluated for three priming durations (4, 8 and 12 hour) in 2014 and 2015. Monitored were seed germination and seedling development of nine sorghum genotypes. Preliminary results showed that hydro-priming significantly improved germination rate, germination speed, number of seminal root, rate of survival and seedling vigour index, compared to non-primed seed treatments. However, seedling length, root length, shoot length and seedling dry weight did not differ significantly. Four out of the nine genotypes evaluated were attributed good seed quality and good response to hydro-priming. The priming with different sources of water resulted in higher seed germination (90%) and seedling development with well and river water, compared to the others. Seed germination rate, uniformity and speed were also enhanced by hydro-priming. It is argued that hydro-priming is a simple but effective method for improving seed germination and seedling development of sorghum. In addition hydro-priming is a safe, simple and inexpensive method to enhance germination. The most promising genotypes have consequently been included in consequent pot

  6. Improving Survival and Growth of Planted Austrocedrus chilensis Seedlings in Disturbed Patagonian Forests of Argentina by Managing Understory Vegetation

    Science.gov (United States)

    Pafundi, Leticia; Urretavizcaya, M. Florencia; Defossé, Guillermo E.

    2014-12-01

    This study was aimed at determining, under field conditions, early interactions between planted cypress seedlings and their associated shrubs in a mesic area of Andean Patagonia and, in a nursery, the effects of increasing light availability on cypress performance when soil water was not a limiting factor. The field experiment was performed in a former cypress-coihue mixed forest (42°02'S, 71°33'W), which was replaced in the 1970s by a plantation of radiata pine. In 2005, 800 cypress seedlings were planted under maqui shrubs in a clear-cut area of the pine stand. In 2007, two treatments were set: no-competition treatment ([NCT] i.e., the surrounding aboveground biomass was removed) and competition treatment ([CT] i.e., without disturbance). The nursery experiment (42°55'S, 71°21'W) consisted of two groups: "shade" (grown under shade cloth) and "sun" (grown at full sun) cypress seedlings. After one growing season, seedling survival and stem growth (in height and diameter) were determined at both sites. Furthermore, the growth rate of leaves, stems, and roots was determined in the nursery. In the field experiment, height growth and survival in NCT were significantly greater than in CT, and a competition process occurred between cypress and surrounding shrubs. In the nursery, sun plants grew more in diameter and increased root weight more than shade plants. Results also showed that in mesic areas of Patagonia, decreasing competition and increasing light levels produced stouter seedlings better adapted to support harsh environmental conditions. Therefore, the removal of protecting shrubs could be a good management practice to improve seedling establishment.

  7. Seed trait-mediated selection by rodents affects mutualistic interactions and seedling recruitment of co-occurring tree species.

    Science.gov (United States)

    Zhang, Hongmao; Yan, Chuan; Chang, Gang; Zhang, Zhibin

    2016-02-01

    As mutualists, seed dispersers may significantly affect mutualistic interactions and seedling recruitment of sympatric plants that share similar seed dispersers, but studies are rare. Here, we compared seed dispersal fitness in two co-occurring plant species (Armeniaca sibirica and Amygdalus davidiana) that inhabit warm temperate deciduous forest in northern China. We tested the hypothesis that seed trait-mediated selection by rodents may influence mutualistic interactions with rodents and then seedling establishment of co-occurring plant species. A. davidiana seeds are larger and harder (thick endocarps) than A. sibirica seeds, but they have similar levels of nutrients (crude fat, crude protein), caloric value and tannin. More A. sibirica seedlings are found in the field. Semi-natural enclosure tests indicated that the two seed species were both harvested by the same six rodent species, but that A. sibirica had mutualistic interactions (scatter hoarding) with four rodent species (Apodemus peninsulae, A. agrarius, Sciurotamias davidianus, Tamias sibiricus), and A. davidiana with only one (S. davidianus). Tagged seed dispersal experiments in the field indicated that more A. sibirica seeds were scatter-hoarded by rodents, and more A. sibirica seeds survived to the next spring and became seedlings. A. sibirica seeds derive more benefit from seed dispersal by rodents than A. davidiana seeds, particularly in years with limited seed dispersers, which well explained the higher seedling recruitment of A. sibirica compared with that of A. davidiana under natural conditions. Our results suggest that seed dispersers may play a significant role in seedling recruitment and indirect competition between co-occurring plant species.

  8. Effects of open-field experimental warming on the growth of two-year-old Pinus densiflora and Abies holophylla seedlings

    Science.gov (United States)

    Han, S.; Son, Y.; Lee, S.; Jo, W.; Yoon, T.; Park, C.; Ko, S.; Kim, J.; Han, S.; Jung, Y.

    2012-12-01

    Temperature increase due to climate change is expected to affect tree growth and distribution [Way and Oren, 2010]. The responses of trees to warming vary with tree species, ontogenic stages, tree life forms, and biomes. Especially, seedling stage is a vulnerable period for tree survival and competition [Saxe et al., 2007] and thus research on effects of temperature increase on seedling stage is needed. We aimed to examine the responses of coniferous seedlings to future temperature increase by conducting an open-field warming experiment. An experimental warming set-up using infra-red heater was built in 2011 and the temperature in warming plots has been regulated to 3°C higher than that of control plots constantly. The seeds of Pinus densiflora and Abies holophylla were planted in each 1 m × 1 m plot (n=3) in April, 2012. Seedling growth, root collar diameter (RCD) and height of 45 individuals of each plot were measured in June and July, 2012. The survival rate of seedlings was also measured. Survival rate of P. densiflora was lower in warming plots (93.3%) than in control plots (100.0%, pdensiflora seedlings were not significantly different between control and warming plots, however, height of A. holophylla was significantly higher in warming plots in June and July (p<0.01). Comparatively, RCD of A. holophylla was only higher in control plots in June. While there is still a lack of case studies on the growth of seedlings under experimental warming, a few studies reported increased seedling growth [Yin et al., 2008] or and no difference [Han et al., 2009] in warming plots. Different responses of seedling growth between two species of the current study might be derived from species-specific acclimation to temperature increase and/or other limiting factors [Way and Oren, 2010]. This result is, to our knowledge, unprecedented and will contribute to the knowledge of species-specific growth response of tree species and to development of model predicting species

  9. Effects of "short" photoperiods on seedling growth of Pinus brutia.

    Science.gov (United States)

    Iakovoglou, V; Radoglou, K; Kostopoulou, P; Dini-Papanastasi, O

    2012-03-01

    This study investigated how nurseries could benefit by inducing "short" photoperiods as low as 4 hr to produce "better" seedlings characterized by more vigorous roots; a substantial feature to overcome transplanting stress. The carryover effect of the photoperiod was also investigated on seedlings that grew for 30 days more underthe consistent 14 hr photoperiod. Seedlings of Pinus brutia were subjected to 4, 6, 8 and 14 hr photoperiod for 3 week. Fifteen seedlings were used to evaluate the leaf area, the root and shoot dry weight and their ratio. Six and sixteen seedlings were used to evaluate the shoot electrolyte leakage and the root growth potential, respectively. Based on the results, the 6 and 8 hr photoperiod indicated greater root allocation (4.8 and 4.9 mg, respectively) and chlorophyll content (3.7 and 4.4, respectively). They also indicated greater leaf area values (3.3 and 3.5 cm2, respectively) along with the 14 hr (3.4 cm2). The photoperiod effect continued even after seedlings were subjected at consistent photoperiod. Overall, "short" photoperiods could provide "better" P. brutia seedlings to accommodate immediate massive reforestation and afforestation needs.

  10. Genetic diversity of seagrass seeds influences seedling morphology and biomass.

    Science.gov (United States)

    Randall Hughes, A; Hanley, Torrance C; Schenck, Forest R; Hays, Cynthia G

    2016-12-01

    Genetic diversity can influence ecological processes throughout ontogeny, yet whether diversity at early life history stages is important in long-lived taxa with overlapping generations is unclear. Seagrass systems provide some of the best evidence for the ecological effects of genetic diversity among adult shoots, but we do not know if the genetic diversity of seeds and seedlings also influences seagrass ecology. We tested the effects of seagrass (Zostera marina) seed diversity and relatedness on germination success, seedling morphology, and seedling production by comparing experimental assemblages of seeds collected from single reproductive shoots ("monocultures") to assemblages of seeds collected from multiple reproductive shoots ("polycultures"). There was no difference in seedling emergence, yet seedlings from polycultures had larger shoots above and below ground than seedlings from monocultures at the end of the 1-yr experiment. Genetic relatedness of the seedlings predicted some aspects of shoot morphology, with more leaves and longer roots and shoots at intermediate levels of relatedness, regardless of seed diversity. Our results suggest that studies of only adult stages may underestimate the importance of genetic diversity if the benefits at early life history stages continue to accrue throughout the life cycle. © 2016 by the Ecological Society of America.

  11. Seed Germination and Seedling Survival of Spartina alterniflora Loisel

    Directory of Open Access Journals (Sweden)

    Patrick D. Biber

    2008-01-01

    Full Text Available Spartina alterniflora (smooth cordgrass is a widespread intertidal salt marsh plant that is frequently used in coastal restoration projects. Seeds collected in 2004 were tested for seed germination and seedling survival after 6 months of cold seed storage to determine differences among collection locations (experiment 1. Seeds collected in 2005, after Hurricane Katrina, were tested for seed germination and seedling survival from 0 to 15 months of cold seed storage time to determine minimum and maximum storage time and seedling survival rates (experiment 2. Seed germination increased from 1-4 months of cold, wet storage (stratification and then began to decline. Survival of the seedlings was highest after 2 months of stratification. In experiment 1, seedling size was found to vary widely among seedlings of the same source and age. Seedling height at 22 days after planting ranged from 2-16 cm, despite identical environmental conditions. Selective breeding could target plants with fast early growth characteristics to promote strains that can be raised quickly in a nursery in response to demands for restoration.

  12. Germination and initial development of aroeira (Myracrodruon urundeuva seedlings

    Directory of Open Access Journals (Sweden)

    Silvana de Paula Quintão Scalon

    2012-12-01

    Full Text Available Aroeira has great economic importance due to its wood useful, tannins extraction and use in the pharmacology. The aim of this work was to evaluate the germination aspects and initial seedlings development of aroeira, under gibberellins, substrata and shading effects, and for that two experiments were led out. In the first one, seeds were previously soaked for 24 hours in water and in 100 mg.L-1 gibberellin solution and were sowed directly in cells trays in the following substrata: land and sand (1:1 and 1:2 and Plantmax . In the second experiment, 15 cm length seedlings were transplanted to polyethylene sacks filled out land+sand+poultry manure (1:1:1 partly decomposed and they were maintained at greenhouse for 15 days. Soon after, seedlings were transferred for the following conditions: shading (50% and full sun and they were 50 mg.L-1 and 150 mg.L-1 gibberellins solutions pulverized, as control seedlings water pulverized. Aroeira seeds should not be previously water or gibberellins imbibed before being sowed. The best substrata for aroeira seeds germination was Plantmax without germinative treatments to reach higher than 80% of seedlings survival. The seedlings developed better at full sun light and the gibberellin. It was observed increment in height, diameter, foliar area and fresh and dry mass from aerial and root part when compared to shading situation. The gibberellins applications did not influence the aroeira seedlings initial growth characteristics.

  13. Effects of benzoic acid and cadmium toxicity on wheat seedlings

    Directory of Open Access Journals (Sweden)

    Kavita Yadav

    2013-06-01

    Full Text Available Benzoic acid (BA and Cd exhibit cumulative effects on plants due to their accumulation in the soil. The present study reports the effects of BA an allelochemical, Cd and their combinations on seed germination, seedling growth, biochemical parameters, and response of antioxidant enzymes in Triticum aestivum L. The experiment was conducted in sand supplemented with Hoagland nutrient solution. Benzoic acid was applied at concentrations of 0.5, 1.0, and 1.5 mM with or without Cd (7 mg L-1 to observe effects of allelochemical and Cd alone and in combination on wheat. Both stresses exhibited inhibitory effect on growth and metabolism of wheat seedlings. The allelochemical in single and combined treatments with Cd decreased seedling growth as compared to Cd stress. The two stresses significantly enhanced malondialdehyde content of wheat seedlings. The activity of other antioxidant enzymes, viz. superoxide dismutase (SOD, catalase (CAT, ascorbate peroxidase (APX, and guaiacol peroxidase (POX were also recorded. SOD increased in seedlings under the two stresses. CAT more prominently ameliorates the toxic effects of H2O2 as compared with APX and POX and protected wheat seedlings from oxidative stress. Allelochemical buttressed the toxic effect of Cd on wheat seedlings.

  14. Survivel, growth, and nutrition of tree seedlings fertilized at planting on Andisol soils in Iceland

    DEFF Research Database (Denmark)

    Oskarsson, Hreinn; Sigurgeirsson, Adalsteinn; Raulund-Rasmussen, Karsten

    2006-01-01

    Ledeb. and Picea sitchensis (Bong.) Carr. After six growing seasons, seedlings provided with controlled-release-fertilizer (Osmocote®: 25 g per seedling) or smaller amounts of easily soluble nitrogen–phosphorus fertilizer (e.g. 1.2 g N per seedling and 1.4 g P per seedling) showed significantly improved...

  15. Early field performance of Acacia koa seedlings grown under subirrigation and overhead irrigation

    Science.gov (United States)

    Anthony S. Davis; Jeremiah R. Pinto; Douglass F. Jacobs

    2011-01-01

    Koa (Acacia koa A. Gray [Fabaceae]) seedlings were grown with subirrigation and overhead irrigation systems in an effort to characterize post-nursery field performance. One year following outplanting, we found no differences in seedling height or survival, but root-collar diameter was significantly larger for subirrigated seedlings. This indicates that koa seedlings,...

  16. Accumulation of nickel ions in seedlings of Vicia sativa L. and manifestations of oxidative stress.

    Science.gov (United States)

    Ivanishchev, V V; Abramova, E A

    2015-05-01

    The accumulation of nickel ions in the roots and shoots of vetch seedlings (Vicia sativa L.) at increasing concentrations of nickel chloride in the medium was studied. It was shown that the accumulation of nickel in the shoots was increased when the concentration of nickel chloride in the medium was more than 50 μM. The bioconcentration factor and sustainability index for vetch seedlings were calculated under the experimental conditions. The obtained results were similar to parameters for other plants, grown on a nutrient medium or soil substrate. First, the obtained results allowed estimate the limits of nickel chloride concentrations for four of five zones, which correspond to the theoretical concept of dose-response curves in the studies on the influence of physiologically essential heavy metals on plants (Prasad 2010). Some parameters of oxidative stress caused by the presence of nickel chloride in the medium were shown. It seems that at low nickel concentrations in the medium in vetch seedlings the increase of several biochemical parameters (catalase activity and proline) caused by the high amylase activity in seeds.

  17. Use of Spent Mushroom Substrate as Growing Media for Tomato and Cucumber Seedlings

    Institute of Scientific and Technical Information of China (English)

    ZHANG Run-Hua; DUAN Zeng-Qiang; LI Zhi-Guo

    2012-01-01

    The aim of this research was to evaluate weathered spent mushroom substrate (SMS),made from spent Flammulina velutipes mushroom substrate,as a growing medium for nursery seedlings.Two vegetable species,cucumber (Cucumis sativus L.cv.Jinchun No.2) and tomato (Solanum lycopersicum L.cv.Mandy),were grown in 8 media of SMS in various ratios with perlite or vermiculite.A mixed substrate of peat with perlite (1∶1; v∶v) was used as the control (CK).The experiment was arranged in a completely randomized design under greenhouse conditions.Prior to sowing,some physical and chemical properties of the growing media were determined.Results showed that all the mixtures had desirable physical and chemical properties for their use in nursery tomato and cucumber seedlings except for the T4 (SMS∶vermiculite =1∶1;v∶v) and the T8 (SMS∶perlite =2∶1; v∶v) mixtures.Compared with the CK,increased plant height,leaf area,fresh weight,dry weight and index of seedling quality were found in the T3 (SMS∶vermiculite =2∶1; v∶v) and T6 (SMS:perlite =4∶1; v∶v) growing media.SMS should be considered as an alternative for the widely used but expensive and resource-limited peat in greenhouse cultivation.

  18. Pretreating dogwood seedlings with simulated acidic precipitation increases dogwood anthracnose symptoms in greenhouse-laboratory trials

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, R.L.; Knighten, J. (USDA Forest Service, Resistance Screening Center, Asheville, NC (United States)); Berrange, P.; Lawton, K.A. (USDA Forest Service, Center for Forest Environmental Studies, Dry Branch, GA (United States)); Britton, K.O. (USDA Forest Service, Southeastern Forest Experiment Station, Athens, GA (United States))

    1993-01-01

    Dogwood anthracnose is the most damaging disease of flowering dogwood (Cornus florida L.) in a large part of the tree's natural range. It is caused by Discula destructiva infection. Previous attempts to inoculate C. florida to produce anthracnose symptoms have met with limited success except when the leaves were pretreated with acidic water, suggesting that acidic precipitation may predispose dogwoods to the disease. This hypothesis was tested in two greenhouse-laboratory studies in which year-old C. florida seedlings were randomly assigned to four treatments of simulated rain (pH 2.5, 3.5, 4.5, and 5.5) in 1989 and 1990. After 10 applications over a 42-d period, the seedlings were moved to a temperature-controlled laboratory, placed in plastic bags, humidified, and sprayed with a spore suspension of five D. destructiva isolates. About 30 d layter, the seedlings were examined for the percentage of leaves exhibiting anthracnose symptoms and disease severity on affected leaves. Both trials showed that as the acidity of the simulated rain increased, the incidence and severity of anthracnose leaf symptoms increased. The 1989 study included a soil lime treatment that showed the same trend but the overall occurrence and severity of symptoms was higher. 17 refs., 5 tabs.

  19. Growth of ponderosa pine seedlings as affected by air pollution

    Science.gov (United States)

    Momen, B.; Anderson, P. D.; Houpis, J. L. J.; Helms, J. A.

    The effect of air pollution on seedling survival and competitive ability is important to natural and artificial regeneration of forest trees. Although biochemical and physiological processes are sensitive indicators of pollution stress, the cumulative effects of air pollutants on seedling vigor and competitive ability may be assessed directly from whole-plant growth characteristics such as diameter, height, and photosynthetic area. A few studies that have examined intraspecific variation in seedling response to air pollution indicate that genotypic differences are important in assessing potential effects of air pollution on forest regeneration. Here, we studied the effects of acid rain (no-rain, pH 5.1 rain, pH 3.0 rain) and ozone (filtered, ambient, twice-ambient) in the field on height, diameter, volume, the height:diameter ratio, maximum needle length, and time to reach maximum needle length in seedlings of three families of ponderosa pine ( Pinus ponderosa Dougl. ex Laws). Seedling diameter, height, volume, and height:diameter ratio related significantly to their pre-treatment values. Twice-ambient ozone decreased seedling diameter compared with ozone-filtered air. A significant family-by-ozone interaction was detected for seedling height, as the height of only one of the three families was decreased by twice-ambient ozone compared with the ambient level. Seedling diameter was larger and the height:diameter ratio was smaller under pH 3.0 rain compared to either the no-rain or the pH 5.1-rain treatment. This suggests greater seedling vigor, perhaps due to a foliar fertilization effect of the pH 3.0 rain.

  20. BIM LAU-PE: Seedlings in Microgravity

    Science.gov (United States)

    Gass, S.; Pennese, R.; Chapuis, D.; Dainesi, P.; Nebuloni, S.; Garcia, M.; Oriol, A.

    2015-09-01

    The effect of gravity on plant roots is an intensive subject of research. Sounding rockets represent a costeffective platform to study this effect under microgravity conditions. As part of the upcoming MASER 13 sounding rocket campaign, two experiments on Arabidopsis thaliana seedlings have been devised: GRAMAT and SPARC. These experiments are aimed at studying (1) the genes that are specifically switched on or off during microgravity, and (2) the position of auxin-transporting proteins during microgravity. To perform these experiments, RUAG Space Switzerland site of Nyon, in collaboration with the Swedish Space Corporation (SSC) and the University of Freiburg, has developed the BIM LAU-PE (Biolology In Microgravity Late Access Unit Plant Experiment). In the following an overview of the BIM LAU-PE design is presented, highlighting specific module design features and verifications performed. A particular emphasis is placed on the parabolic flight experiments, including results of the micro-g injection system validation.

  1. Arborescent palm seed morphology and seedling distribution

    Directory of Open Access Journals (Sweden)

    Rodolfo Salm

    Full Text Available This study examines how the seed morphology of two large arborescent palms, Attalea maripa (Aubl. Mart. and Astrocaryum aculeatum G. Mey, may affect their seed shadow in a seasonally dry Amazonian forest. In addition to being smaller and produced in larger numbers than those of A. aculeatum, A. maripa seeds also presented a substantially lower amount of nutritional reserves available for the embryo. However, A. maripa seedlings were found in much higher numbers than those of A. aculeatum. The results suggest that, within the spatial scale considered, the seed rain of A. maripa is more restricted to the area surrounding around reproductive conspecifics than that of A. aculeatum. Furthermore, in comparison with those of A. aculeatum, the smaller seeds of A. maripa might be less attractive to scatterhoarding rodents (e.g. Dasyprocta aguti. The pattern observed emphasizes the importance of scatterhoarding rodents as dispersers of large-seeded plant species in Neotropical forests.

  2. Arborescent palm seed morphology and seedling distribution.

    Science.gov (United States)

    Salm, Rodolfo

    2005-11-01

    This study examines how the seed morphology of two large arborescent palms, Attalea maripa (Aubl.) Mart. and Astrocaryum aculeatum G. Mey, may affect their seed shadow in a seasonally dry Amazonian forest. In addition to being smaller and produced in larger numbers than those of A. aculeatum, A. maripa seeds also presented a substantially lower amount of nutritional reserves available for the embryo. However, A. maripa seedlings were found in much higher numbers than those of A. aculeatum. The results suggest that, within the spatial scale considered, the seed rain of A. maripa is more restricted to the area surrounding around reproductive conspecifics than that of A. aculeatum. Furthermore, in comparison with those of A. aculeatum, the smaller seeds of A. maripa might be less attractive to scatterhoarding rodents (e.g. Dasyprocta aguti). The pattern observed emphasizes the importance of scatterhoarding rodents as dispersers of large-seeded plant species in Neotropical forests.

  3. Tree Seed and Seedling Supply Systems

    DEFF Research Database (Denmark)

    Nyoka, Betserai I.; Roshetko, James M.; Jamnadass, Ramni

    2015-01-01

    The paper reviews tree seed and seedling supply systems in sub-Saharan Africa, Asia and Latin America. Across these regions, the review found that some of the germplasm supply systems do not efficiently meet farmers’ demands and environmental expectations in terms of productivity, species...... and genetic diversity. In some countries, germplasm used is mostly sourced from undocumented sources and often untested. Germplasm quality control systems are only found in a few countries. Appreciation of the value of tree germplasm of high genetic quality is low. Non-government organisations (NGOs) in many...... out private entrepreneurs, although this is not substantiated by any evidence to suggest that the smallholder farmers are willing and able to pay for the germplasm. In some Latin American countries, private companies, government and NGOs provide farmers tree germplasm in a partnership in which farmers...

  4. Growth strategies and threshold responses to water deficit modulate effects of warming on tree seedlings from forest to alpine

    Science.gov (United States)

    Lazarus, Brynne E.; Castanha, Cristina; Germino, Matthew; Kueppers, Lara M.; Moyes, Andrew B.

    2017-01-01

    1.Predictions of upslope range shifts for tree species with warming are based on assumptions of moisture stress at lower elevation limits and low temperature stress at high elevation limits. However, recent studies have shown that warming can reduce tree seedling establishment across the entire gradient from subalpine forest to alpine via moisture limitation. Warming effects also vary with species, potentially resulting in community shifts in high elevation forests. 2.We examined the growth and physiology underlying effects of warming on seedling demographic patterns. We evaluated dry mass (DM), root length, allocation above- and belowground, and relative growth rate (RGR) of whole seedlings, and their ability to avoid or endure water stress via water-use efficiency and resisting turgor loss, for Pinus flexilis, Picea engelmannii and Pinus contorta seeded below, at, and above treeline in experimentally warmed, watered, and control plots in the Rocky Mountains, USA. We expected that growth and allocation responses to warming would relate to moisture status and that variation in drought tolerance traits would explain species differences in survival rates. 3.Across treatments and elevations, seedlings of all species had weak turgor-loss resistance, and growth was marginal with negative RGR in the first growth phase (-0.01 to -0.04 g/g/d). Growth was correlated with soil moisture, particularly in the relatively small-seeded P. contorta and P. engelmannii. P. flexilis, known to have the highest survivorship, attained the greatest DM and longest root but was also the slowest growing and most water-use-efficient. This was likely due to its greater reliance on seed reserves. Seedlings developed 15% less total DM, 25% less root DM, and 11% shorter roots in heated compared to unheated plots. Higher temperatures slightly increased DM, root length and RGR where soils were wettest, but more strongly decreased these variables under drier conditions. 4.Synthesis: The surprising

  5. Effect of SiO2 nanoparticles on drought resistance in hawthorn seedlings

    Directory of Open Access Journals (Sweden)

    Ashkavand Peyman

    2015-12-01

    Full Text Available Drought is a significant factor limiting crop production in arid regions while hawthorns (Crataegus sp. are an important component of such region’s forests. Therefore, treatments that increase hawthorn drought resistance may also increase transplanting success. Thus, the physiological and biochemical responses of hawthorn seedlings to a factorial combination of different concentrations of silica nanoparticles (SNPs at 0, 10, 50 and 100 mg L−1 and three soil moisture treatments (without stress, moderate stress and severe stress were investigated. Seedlings were irrigated with one of the four concentrations of SNPs for 45 days before exposing them to drought stress. Photosynthesis parameters, malondialdehyde (MDA, relative water content (RWC, membrane electrolyte leakage (ELI as well as chlorophyll, carotenoid, carbohydrate and proline content were determined. At the end of the experiment, positive effects by SNP pre-treatment on physiological indexes were observed during drought stress. Under drought conditions, the effect of SNPs on photosynthetic rate and stomatal conductance was evident. Although the SNPs increased plant biomass, xylem water potential and MDA content, especially under drought conditions, RWC and ELI were not affected by the SNP pre-treatments. Seedlings pre-treated with SNPs had a decreased carbohydrate and proline content under all water regimes, but especially so under drought. Total chlorophyll content and carotenoid content did not change among the treatments. Generally, the findings imply that SNPs play a positive role in maintaining critical physiological and biochemical functions in hawthorn seedlings under drought stress conditions. However, more studies are needed before the physiological and biochemical basis of induced drought resistance can be determined.

  6. Fungicidal control of Lophodermium seditiosum on Pinus sylvestris seedlings in Swedish forest nurseries

    Energy Technology Data Exchange (ETDEWEB)

    Stenstroem, Elna [Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Dept. of Forest Mycology and Pathology; Arvidsson, Bernt [Svenska Skogsplantor AB, Joenkoeping (Sweden)

    2001-07-01

    During the 1990s, there were serious outbreaks of the pathogen Lophodermium seditiosum on pine seedlings in Swedish forest nurseries, even though the seedlings had been treated with the fungicide propiconazole. The present experiment was carried out to evaluate two other fungicides, fluazinam and azoxystrobin, as possible alternatives to propiconazole. In the tests, which were all carried out in the same forest nursery, seedlings were treated with either propiconazole, fluazinam. or azoxystrobin, and the proportion of needles with ascocarps of L. seditiosum and the number of ascocarps per needle were recorded over the following 2 yrs. Seedlings treated with azoxystrobin already appeared healthier than control seedlings in September of the first year, and by November all azoxystrobin-treated seedlings had fewer ascocarps per needle compared with control seedlings. In autumn of the second year, there were no ascocarps on seedlings treated with fluazinam or azoxystrobin, whereas seedlings treated with propiconazole had similar numbers of ascocarps to non-treated control seedlings.

  7. Biological seed priming mitigates the effects of water stress in sunflower seedlings

    OpenAIRE

    Singh, Narsingh Bahadur; Singh, Deepmala; Singh, Amit

    2015-01-01

    The sunflower (Helianthus annuus L. cv. PAC 36) seedlings were inoculated with plant growth promoting rhizobacteria (PGPR), viz. Azotobacter chroococcum (A+), Bacillus polymyxa (B+), separately and in combination of the two (AB+). Relative water content and seedling growth were maximum in AB+ seedlings under control. Water stress significantly decreased the RWC, growth and dry mass of non-inoculated seedlings. However, inoculated seedlings maintained higher growth even under water stress. Pig...

  8. Pulse seedling recruitment on the population dynamics of a columnar cactus: Effect of an extreme rainfall event

    Science.gov (United States)

    Arroyo-Cosultchi, Gabriel; Golubov, Jordan; Mandujano, María C.

    2016-02-01

    Demographic studies on the Cactaceae have highlighted several threats which are clearly human induced (e.g., disturbance) or intrinsic to their biology (e.g., infrequent recruitment). Most demographic studies suggest that early life stages of germination and seedling recruitment are crucial and often a limitation for population growth. The population dynamics of Neobuxbaumia polylopha (DC) Backeb. was modeled for a three-year period to assess the contribution of the early life cycle stages on population growth rate (λ). Two annual size-classified matrix population models were constructed for standard analysis, applied a life table response experiment (LTRE) analysis to explore the contributions of demographic processes, plant size, and temporal variability (years) to λ, and changes in the matrix elements were simulated including a seed bank, and seed-to-seedling transition using observed and experimental data. The population growth rates for 2012-2013 and 2013-2014 were 0.9916 (0.9906-0.9929) and 1.0216 (1.011-1.0280) respectively, suggesting two opposite growth rates for the studied period. The increase in λ in 2013-2014 was driven primarily by the increased growth and seedling recruitment and survival of small individuals. The rate of recruitment was higher in 2013-2014 with a left-skewed stable size distribution. Elasticity values were high for matrix entries corresponding to individuals remaining in the same category (stasis), followed by growth, retrogression and fecundity. The simulations show that the seed bank has a minor effect in comparison with the seed-seedling transition which became the population bottleneck under the assumption that seeds are not limited, so programs designed to preserve N. polylopha populations must focus on seedling establishment.

  9. Inheritance of autumn frost hardiness in Pinus sylvestris L. seedlings.

    Science.gov (United States)

    Norell, L; Eriksson, G; Ekberg, I; Dormling, I

    1986-07-01

    Inheritance of frost hardiness was analysed making use of a 12×12 incomplete factorial mating design. Owing to space limitations only 59 families could be tested in four experiments. To link the four experiments, some families were common to two or more experiments. The seedlings were grown in climate chambers under conditions inducing autumn hardening. The plants were exposed to a freezing temperature of -10 °C for three hours at night lengths of 11-13 h. A statistical model was developed for analyses of variance of our data. The genetic variation and the variation due to the cultivation regimes during autumn hardening were of the same magnitude. The additive effects were the most important ones for induction of frost damage. No interaction following long-distance crossing was noted. Mixed model equations were used for ranking of the parents. The results obtained support a polygenic inheritance of frost hardiness. The large within-population variation offers good opportunities for hardiness breeding.

  10. Hunting alters seedling functional trait composition in a Neotropical forest.

    Science.gov (United States)

    Kurten, Erin L; Wright, S Joseph; Carson, Walter P

    2015-07-01

    Defaunation alters trophic interactions between plants and vertebrates, whichmay disrupt trophic cascades, thereby favoring a subset of plant species and reducing diversity. If particular functional traits characterize the favored plant species,.then defaunation may alter community-wide patterns of functional trait composition. Changes in plant functional traits occurring with defaunation may help identify the species interactions affected by defaunation and the potential for other cascading effects of defaunation. We tested the hypotheses that defaunation would (1) disrupt seed dispersal, thereby favoring species whose dispersal agents are not affected (e.g., small birds, bats, and abiotic agents), (2) reduce seed predation, thereby favoring larger-seeded species, and (3) reduce herbivory, thereby favoring species with lower leaf mass per area (LMA), leaf toughness, and wood density. We examined how these six traits responded to vertebrate defaunation caused by hunters or by experimental exclosures among more than-30 000 woody seedlings in a lowland tropical moist forest. Exclosures reduced terrestrial frugivores, granivores, and herbivores, while hunters also reduced volant and arboreal frugivores and granivores. The comparison of exclosures and hunting allowed us to parse the impacts of arboreal and volant species (reduced by hunters only) and terrestrial species (reduced by both hunters and exclosures). The loss of terrestrial vertebrates alone had limited effects on plant trait composition. The additional loss of volant and arboreal vertebrates caused significant shifts in plant species composition towards communities with more species dispersed abiotically, including lianas and low wood-density tree species, and fewer species dispersed by large vertebrates. In contrast to previous studies, community seed mass did not decline significantly in hunted sites. Our exclosure results suggest this is because reducing seed predators disproportionately benefits large

  11. A leaf phosphorus assay for seedlings of Acacia mangium.

    Science.gov (United States)

    Sun, J S; Simpson, R J; Sands, R

    1992-10-01

    Concentrations of extractable and total phosphorus in leaves, stem, root and nodules of 12-week-old seedlings of two provenances of Acacia mangium Willd. were analyzed to identify the fraction of phosphorus and the plant part most suitable for predicting the phosphorus nutritional status of the seedlings.For both provenances, concentrations of extractable phosphorus were more sensitive to changes in soil phosphorus status and varied less among different plant parts than concentrations of total phosphorus. Concentrations of extractable phosphorus in the youngest fully expanded leaf (Leaf 3 from the apex) and the next two older leaves correlated closely with seedling dry mass and may be used to assess the phosphorus nutritional status of Acacia mangium seedlings.

  12. Strong microsite control of seedling recruitment in tundra

    DEFF Research Database (Denmark)

    Graae, Bente J; Ejrnæs, Rasmus; Lang, Simone I

    2011-01-01

    , the experimental seed addition showed that the microsite environment was even more important. For all species, seedling emergence peaked at the productive end of the gradient, irrespective of the adult niches realized. Disturbance promoted recruitment at all positions along the environmental gradient, not just......The inclusion of environmental variation in studies of recruitment is a prerequisite for realistic predictions of the responses of vegetation to a changing environment. We investigated how seedling recruitment is affected by seed availability and microsite quality along a steep environmental...... at high productivity. Early seedling emergence constituted the main temporal bottleneck in recruitment for all species. Surprisingly, winter mortality was highest at what appeared to be the most benign end of the gradient. The results highlight that seedling recruitment patterns are largely determined...

  13. Seedlings and Saplings - Spears and Didion Ranches [ds318

    Data.gov (United States)

    California Department of Resources — These data are the total number and average number of saplings and seedlings of trees detected from 0.05-ha circular plot habitat samples taken in 2005 at sample...

  14. Identification of zygotic and nucellar seedlings in polyembryonic mango cultivars

    Directory of Open Access Journals (Sweden)

    Elisa del Carmen Martínez Ochoa

    2012-11-01

    Full Text Available The objective of this work was to evaluate the occurrence of polyembryony in the mango cultivars Manila and Ataulfo, and to determine whether seedlings cultured in vitro are zygotic or nucelar. Percentage of polyembryony was calculated and the number of embryos in 100 seeds of each cultivar was recorded. 'Manila' exhibited 97% polyembryony with 3.4 embryos per seed, while 'Ataulfo' had 95% polyembryony with 3.2 embryos per seed. Later, 20 seeds of each cultivar were established in vitro, and it was analyzed those in which all embryos germinated (12 seeds from 'Manila' and 7 from 'Ataulfo'. DNA was extracted from seedling leaf tissue, and its origin was identified with 14 RAPD primers. The polymorphic markers recognized the seedlings of sexual origin in seven of nine 'Manila' polyembryonic seeds, and in four of seven 'Ataulfo' ones. Also, in polyembryonic seeds not all zygotic seedlings were produced by small embryos located at the micropyle.

  15. [Effects of exogenous nitric oxide on the subcellular distribution and chemical forms of copper in tomato seedlings under copper stress].

    Science.gov (United States)

    Jiang, Chun-Hui; Wang, Xiu-Feng; Yin, Bo; Li, Xiao-Yun; Cui, Xiu-Min

    2012-11-01

    A nutrient solution culture experiment was conducted to study the effects of exogenous NO donor (sodium nitroprusside) on the subcellular distribution and chemical form of copper (Cu) in tomato seedlings under the stress of 50 micromol x L(-1) of Cu2+ (CuCl2). Under this stress, the biomass and plant height of tomato seedlings decreased by 33.7% and 23.1%, respectively. Exogenous NO alleviated this inhibition effect significantly, but the Cu concentration and accumulation in the seedling organs still had a significant increase. Under the Cu stress, the Cu concentration and accumulation in the seedling organs were in the order of root > leaf > stem > petiole. Exogenous NO limited the absorbed Cu transferred from root to shoot, but could not remove this translocation. Exogenous NO increased the Cu concentration in vacuole and cell wall significantly, and decreased the Cu concentration in organelle, which lessened the damage of Cu on the regular metabolic balance in cytoplasm and increased the tolerance of organelle against Cu. Exogenous NO increased the acetic acid-extractable Cu (F(HAc)) in root, sodium chloride-extractable Cu (F(NaCl)) in stem, F(HAc) in petiole, and ethanol-extractable Cu (F(E)) and F(NaCl) in leaf, while decreased the concentration and distribution of water-extractable Cu (F(W)) in different organs, which efficiently reduced the bio-toxicity of excessive copper.

  16. Control of reed canarygrass promotes wetland herb and tree seedling establishment in an upper Mississippi River Floodplain forest

    Science.gov (United States)

    Thomsen, Meredith; Brownell, Kurt; Groshek, Matthew; Kirsch, Eileen

    2012-01-01

    Phalaris arundinacea (reed canarygrass) is recognized as a problematic invader of North American marshes, decreasing biodiversity and persisting in the face of control efforts. Less is known about its ecology or management in forested wetlands, providing an opportunity to apply information about factors critical to an invader's control in one wetland type to another. In a potted plant experiment and in the field, we documented strong competitive effects of reed canarygrass on the establishment and early growth of tree seedlings. In the field, we demonstrated the effectiveness of a novel restoration strategy, combining site scarification with late fall applications of pre-emergent herbicides. Treatments delayed reed canarygrass emergence the following spring, creating a window of opportunity for the early growth of native plants in the absence of competition from the grass. They also allowed for follow-up herbicide treatments during the growing season. We documented greater establishment of wetland herbs and tree seedlings in treated areas. Data from small exclosures suggest, however, that deer browsing can limit tree seedling height growth in floodplain restorations. Slower tree growth will delay canopy closure, potentially allowing reed canarygrass re-invasion. Thus, it may be necessary to protect tree seedlings from herbivory to assure forest regeneration.

  17. Response of Pinus halepensis Mill. seedlings to biosolids enriched with Cu, Ni and Zn in three Mediterranean forest soils

    Energy Technology Data Exchange (ETDEWEB)

    Fuentes, David [Fundacion CEAM, Universidad de Alicante, Ap 99, 03080 Alicante (Spain)]. E-mail: david.fuentes@ua.es; Disante, Karen B. [Dept. d' Ecologia, Universitat d' Alacant, Ap 99, 03080 Alicante (Spain)]. E-mail: kb.disante@ua.es; Valdecantos, Alejandro [Fundacion CEAM, Universidad de Alicante, Ap 99, 03080 Alicante (Spain) and Dept. Ecosistemas Agroforestales (EPS Gandia), Universidad Politecnica de Valencia. Ctra. Nazaret-Oliva s/n. 46730 Gandia, Valencia (Spain)]. E-mail: a.valdecantos@ua.es; Cortina, Jordi [Dept. d' Ecologia, Universitat d' Alacant, Ap 99, 03080 Alicante (Spain)]. E-mail: jordi@ua.es; Ramon Vallejo, V. [Fundacion CEAM, Universidad de Alicante, Ap 99, 03080 Alicante (Spain)]. E-mail: ramonv@ceam.es

    2007-01-15

    We investigated the response of Pinus halepensis seedlings to the application of biosolids enriched with Cu, Ni and Zn on three Mediterranean forest soils under semiarid conditions. One-year-old seedlings were planted in lysimeters on soils developed from marl, limestone and sandstone which were left unamended, amended with biosolids, or amended with biosolids enriched in Cu, Ni and Zn. Enriched biosolids increased plant heavy metal concentration, but always below phytotoxic levels. Seedlings receiving unenriched biosolids showed a weak reduction in Cu and Zn concentration in needles, negatively affecting physiological status during drought. This effect was alleviated by the application of enriched sludge. Sewage sludge with relatively high levels of Cu, Zn and Ni had minor effects on plant performance on our experimental conditions. Results suggest that micronutrient limitations in these soils may be alleviated by the application of biosolids with a higher Cu, Zn and Ni content than those established by current regulations. - Biosolid-borne Cu, Ni and Zn did not show negative effects on Pinus halepensis seedlings performance after application on three Mediterranean forest soils.

  18. Multivariate and Clustering Analysis in Sweet Tamarind Seedling Progenies

    OpenAIRE

    D. Saraladevi, V. Ponnuswami, R.M. Vijayakumar and S.Chitra

    2010-01-01

    Seventy eight seedling progenies of a sweet tamarind type collected from Dindigul region were planted at HorticulturalCollege and Research Institute, Periyakulam during September 2005. These seedling progenies in pre bearing stagewere evaluated to assess the variability existing in respect of growth parameters viz., tree height, girth and canopyspread. Among the three characters studied, canopy spread exhibited highest correlation with girth (0.61) than treeheight (0.21). Tree height having h...

  19. Study on Quantitative Character for Anatomy in Tomato Seedling Stem

    Institute of Scientific and Technical Information of China (English)

    LI Fuheng; WEI Liyan; YU Longfeng; QI Donglai; ZHANG Da

    2009-01-01

    The results of quantitative characters for anatomy in stems of three varieties tomatoes seedlings showed that the cell population between vascular bundle and epidermis, the cellular layers among vascular bundles and the cell population in an unit area(mm2) of no vascular bundle areas were similar and there had small difference among three varieties. On the foundation of these studies, the developmental mechanism of tomato seedling stem was discussed.

  20. Effects of gravel mulch on emergence of galleta grass seedlings. Oral summary report

    Energy Technology Data Exchange (ETDEWEB)

    Winkel, V.K.; Medrano, J.C.; Stanley, C.; Walo, M.D.

    1993-03-01

    The Department of Energy Nevada Operations Office, Technology Development and Program Management Division, has identified the need to clean up several sites on the Nevada Test Site and Tonopah Test Range contaminated with surface plutonium. An important objective of the project identified as the Plutonium In Soils Integrated Demonstration is to develop technologies to stabilize and restore the disturbed sites after decontamination. Revegetation of these contaminated sites will be difficult due to their location in the arid Mojave and Great Basin Deserts. The major factors which will affect successful plant establishment and growth at these sites are limited and sporadic precipitation, limited soil water, extreme air and soil temperatures, limited topsoil, and herbivory . Research has shown that providing microsites for seed via mulching can aid in plant emergence and establishment. Since many of the soils at the sites slated for plutonium decontamination have a large percentage of gravel in the upper 10 cm of soil, the use of gravel as mulch could provide microsites for seed and stabilize soils during subsequent revegetation of the sites. In July 1992, EG&G/EM Environmental Sciences Department initiated a greenhouse study to examine the possible benefits of gravel mulch. The specific objectives of this greenhouse study were to: (1) determine the effects seedling emergence and soil water, and (2) determine effects of irrigation rates on seedling emergence for gravel mulches and other conventional seedbed preparation techniques. A secondary objective was to determine the depth of gravel mulch that was optimal for seedling emergence. Results from this greenhouse study will assist in formulating specific reclamation plans for sites chosen for cleanup.

  1. Silvicultural Attempts to Induce Browse Resistance in Conifer Seedlings

    Directory of Open Access Journals (Sweden)

    Bruce A. Kimball

    2011-01-01

    Full Text Available A multiyear study was conducted to determine if soil amendment combined with topical application of elemental sulfur could be employed to reduce deer browse damage to four conifer species. Fertilizer and sulfur were applied to conifer seedlings at seven sites near Corvallis, OR. Growth and browse damage data were collected for all seedlings over a period of 17 months. Additionally, foliar concentrations of monoterpenes and simple carbohydrates were assessed in western redcedar (Thuja plicata seedlings over a period of three years. Fertilization and sulfur treatments had a moderate impact on growth and no influence on browse damage or the chemical responses. Over the course of the study, browse damage diminished while foliar monoterpene concentrations increased in redcedar. It appears that silvicultural manipulation via sulfur application and/or soil amendment cannot accelerate or alter the ontogenetical changes that may naturally defend seedlings against mammalian herbivores. In a brief trial with captive deer, redcedar browse resistance was influenced by seedling maturation, but not monoterpene content. Other maturation effects may yield significant browse protection to young seedlings.

  2. Growth of white tabebuia seedlings in different substrates

    Directory of Open Access Journals (Sweden)

    Marichel Canazza de Macedo

    2011-03-01

    Full Text Available The objective of this work was to evaluate the white tabebuia (Tabebuia roseo-alba (Ridl. Sandwith seedlings emergence and growth in the beds according to different substrates. Two independent experiments were conducted. The emergence study was carried out in six substrates: 1- Plantmax®; 2- vermiculite; 3- sand; 4- soil + sand (1:1; 5- soil + carbonized rice husk (1:1; 6- soil + sand + carbonized rice husk (2:1:1 (v/v, and the experiment was set up according to a three-replicate randomized complete-block design. The growth study of seedlings was carried out according to a five-replicate randomized complete-block design with five substrates: 1- soil + sand (1:1; 2- soil + semi decomposed chicken manure (1:1; 3- soil + carbonized rice husk (1:1; 4- soil + sand + semi decomposed chicken manure (1:1:1; 5- soil + sand + carbonized rice husk (1:1:1 (v/v. The height results of seedling emergence, emergence speed index and the stem height were observed with Plantmax®, vermiculite, soil + carbonized rice husk and soil + sand + carbonized rice husk. The best results of seedling height, stem diameter, chlorophyll index, leaf area, root length and the stem dry mass weight and root were observed in the substrates with semi decomposed chicken manure. It is recommended the use of P, V, SC or SAC for seedling germination and emergence and SACF or SCF for seedling growth of white tabebuia.

  3. Wood formation in Abies balsamea seedlings subjected to artificial defoliation.

    Science.gov (United States)

    Rossi, Sergio; Simard, Sonia; Deslauriers, Annie; Morin, Hubert

    2009-04-01

    We determined the cambial sensitivity and quantified the anatomical differences in xylem of Abies balsamea (L.) Mill. seedlings subjected to artificial defoliation to simulate spruce budworm feeding. Defoliation was performed by removing two-thirds of needles of all current-year shoots for up to four consecutive growth cycles to account for inter- and intra-annual xylem formation. In Experiment 1, xylem development was studied from May to October 2005 in seedlings defoliated at the end of June. In Experiment 2, anatomical features of the xylem were measured along the tree rings formed in 2005 and 2006 during the four cycles of growth and defoliation. Control and defoliated seedlings showed similar patterns of cambial activity and timing of xylem differentiation, although fewer enlarging cells were observed in August to September in defoliated seedlings. Tree-ring widths were similar in control and defoliated seedlings, with thinner rings produced in the greenhouse in winter. No effect of defoliation on cell lumen area was observed, and effects on radial cell diameter and wall thickness were found only occasionally. The results indicate that the A. balsamea seedlings produced all the resources required to maintain stem growth during the four cycles of defoliation.

  4. Effect of Salt Stress on Transpiration and Ion Distribution in Seedlings of Four Tree Species

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Transpiration rate and ion distribution of pagoda tree, walnut, velvet ash and poplar seedlings treated by NaCl solution of 0, 50, 100, 200 mmol·L-1 were studied. The results showed that there were significant differences in the response to NaCl among the four tree species. Na+ exclusion capacity of pagoda tree was the largest among the four species. The Na+ exclusion capacity of velvet ash was less than that of pagoda tree. Salt excretion capacity of velvet ash was limited. Its salt-tolerance was bigge...

  5. Root-zone cooling effect of water-cooled seedling bed on growth of tomato seedling%水冷式苗床根际降温效果及其对番茄幼苗生长的影响

    Institute of Scientific and Technical Information of China (English)

    李胜利; 师晓丹; 夏亚真; 孙治强

    2014-01-01

    作为水分和养分吸收运输的主要器官,根系及其代谢直接影响着植株的生长与发育,相对于地上部温度植株对地温更为敏感。根际高温是影响夏季蔬菜集约化育苗主要障碍因子之一,适宜、稳定的根际温度是幼苗根系生长和培育壮苗的重要保证。为了降低夏季集约化育苗时幼苗的根际高温环境,设计了一种低能耗的根际降温方式,该研究利用地下水作为降温媒介,采用梯形排管作为冷却管道,设计了一套水冷式苗床用于集约化育苗根际局部降温。试验结果表明,在番茄育苗期间,水冷式苗床番茄幼苗根际积温、日均温和平均最高温分别比对照苗床降低了154.1、4.5和6.5℃。水冷式苗床平均一天中番茄幼苗根际温度高于25℃历时比对照苗床减少了7.6 h,高于28℃历时比对照苗床减少了7.2 h。水冷式苗床番茄幼苗叶片的蒸腾速率比对照提高了36.3%,提高了叶-气温差。水冷式苗床番茄幼苗根系活力和光合作用显著高于对照苗床,壮苗指数比对照苗床提高了34.9%。因此,水冷式降温苗床能够较好的降低根际温度,缓解夏季高温对番茄幼苗生长的胁迫。%As the main plant organ of absorbing and transporting water and nutrients, root system and its metabolism directly affect plant growth and development.Plant growth is more susceptible to root zone temperature than above ground portion. The root zone temperature greatly affects the growth and physiological metabolism of plant. Optimal and stable rhizosphere temperature is an important factor for root growth and metabolism. The heat stress around rhizosphere during summer season is an important factor limiting the seedling growth. Root-zone cooling is more economical compared with air temperature cooling, it can be an effective solution to alleviate high temperature stress. A new water-cooled seedling bed (WSD) was exploited by using

  6. Effectiveness of Low-Cost Planting Techniques for Improving Water Availability to Olea europaea Seedlings in Degraded Drylands

    OpenAIRE

    Valdecantos Dema, Alejandro; Fuentes Delgado, David; Smanis, Athanasios; Llovet López, Joan; Morcillo Juliá, Luna; Bautista Aguilar, Susana

    2014-01-01

    Reforestation projects in semiarid lands often yield poor results. Water scarcity, poor soil fertility, and structure strongly limit the survival and growth of planted seedlings in these areas. At two experimental semiarid sites, we evaluated a variety of low-cost planting techniques in order to increase water availability to plants. Treatments included various combinations of traditional planting holes; water-harvesting microcatchments; stone or plastic mulches; small waterproof sheets to in...

  7. Growth and nitrogen acquisition strategies of Acacia senegal seedlings under exponential phosphorus additions.

    Science.gov (United States)

    Isaac, M E; Harmand, J M; Drevon, J J

    2011-05-15

    There remains conflicting evidence on the relationship between P supply and biological N(2)-fixation rates, particularly N(2)-fixing plant adaptive strategies under P limitation. This is important, as edaphic conditions inherent to many economically and ecologically important semi-arid leguminous tree species, such as Acacia senegal, are P deficient. Our research objective was to verify N acquisition strategies under phosphorus limitations using isotopic techniques. Acacia senegal var. senegal was cultivated in sand culture with three levels of exponentially supplied phosphorus [low (200 μmol of P seedling(-1) over 12 weeks), mid (400 μmol) and high (600 μmol)] to achieve steady-state nutrition over the growth period. Uniform additions of N were also supplied. Plant growth and nutrition were evaluated. Seedlings exhibited significantly greater total biomass under high P supply compared to low P supply. Both P and N content significantly increased with increasing P supply. Similarly, N derived from solution increased with elevated P availability. However, both the number of nodules and the N derived from atmosphere, determined by the (15)N natural abundance method, did not increase along the P gradient. Phosphorus stimulated growth and increased mineral N uptake from solution without affecting the amount of N derived from the atmosphere. We conclude that, under non-limiting N conditions, A. senegal N acquisition strategies change with P supply, with less reliance on N(2)-fixation when the rhizosphere achieves a sufficient N uptake zone.

  8. The role of carbohydrates in seed germination and seedling establishment of Himatanthus sucuuba, an Amazonian tree with populations adapted to flooded and non-flooded conditions

    Science.gov (United States)

    da Silva Ferreira, Cristiane; Piedade, Maria Teresa Fernandez; Tiné, Marco Aurélio Silva; Rossatto, Davi Rodrigo; Parolin, Pia; Buckeridge, Marcos Silveira

    2009-01-01

    Background and Aims In the Amazonian floodplains plants withstand annual periods of flooding which can last 7 months. Under these conditions seedlings remain submerged in the dark for long periods since light penetration in the water is limited. Himatanthus sucuuba is a tree species found in the ‘várzea’ (VZ) floodplains and adjacent non-flooded ‘terra-firme’ (TF) forests. Biochemical traits which enhance flood tolerance and colonization success of H. sucuuba in periodically flooded environments were investigated. Methods Storage carbohydrates of seeds of VZ and TF populations were extracted and analysed by HPAEC/PAD. Starch was analysed by enzyme (glucoamylase) degradation followed by quantification of glucose oxidase. Carbohydrate composition of roots of VZ and TF seedlings was studied after experimental exposure to a 15-d period of submersion in light versus darkness. Key Results The endosperm contains a large proportion of the seed reserves, raffinose being the main non-structural carbohydrate. Around 93 % of the cell wall storage polysaccharides (percentage dry weight basis) in the endosperm of VZ seeds was composed of mannose, while soluble sugars accounted for 2·5%. In contrast, 74 % of the endosperm in TF seeds was composed of galactomannans, while 22 % of the endosperm was soluble sugars. This suggested a larger carbohydrate allocation to germination in TF populations whereas VZ populations allocate comparatively more to carbohydrates mobilized during seedling development. The concentration of root non-structural carbohydrates in non-flooded seedlings strongly decreased after a 15-d period of darkness, whereas flooded seedlings were less affected. These effects were more pronounced in TF seedlings, which showed significantly lower root non-structural carbohydrate concentrations. Conclusions There seem to be metabolic adjustments in VZ but not TF seedlings that lead to adaptation to the combined stresses of darkness and flooding. This seems to be

  9. Phosphorus requirements for containerized Pterocarpus indicus seedlings

    Institute of Scientific and Technical Information of China (English)

    Eng Hai Lok; Bernard Dell

    2015-01-01

    Pterocarpus indicus Willd is a tropical woody legume that holds promise for plantation forestry. Two glasshouse experiments were undertaken on two soil types to determine the phosphorus (P) concentration ranges in the foliage of P-stressed and healthy plants, and to define cri-tical P concentrations for the diagnosis of deficiency and toxicity. There was a narrow range in rates of P fertilizer, supplied as Ca(H2PO4)2?H20, between deficiency and toxicity compared to other tree species. The relationship between shoot yield and P concentration in the youngest fully expanded leaf enabled critical P concentrations for the diagnosis of deficiency (0.17%) and toxicity (0.41%) to be determined at 90% maximum yield from linear re-gressions fitted to the data. The foliar P concentration ranges for deficiency and toxicity were similar to other nitrogen-fixing trees. The defined P concentration ranges and the critical P concentrations for the diagnosis of P deficiency and P toxicity should be useful for monitoring the P status of nursery stock and the health of young seedlings after out-planting.

  10. The Vibration Ring. Phase 1; [Seedling Fund

    Science.gov (United States)

    Asnani, Vivake M.; Krantz, Timothy L.; Delap, Damon C.; Stringer, David B.

    2014-01-01

    The vibration ring was conceived as a driveline damping device to prevent structure-borne noise in machines. It has the appearance of a metal ring, and can be installed between any two driveline components like an ordinary mechanical spacer. Damping is achieved using a ring-shaped piezoelectric stack that is poled in the axial direction and connected to an electrical shunt circuit. Surrounding the stack is a metal structure, called the compression cage, which squeezes the stack along its poled axis when excited by radial driveline forces. The stack in turn generates electrical energy, which is either dissipated or harvested using the shunt circuit. Removing energy from the system creates a net damping effect. The vibration ring is much stiffer than traditional damping devices, which allows it to be used in a driveline without disrupting normal operation. In phase 1 of this NASA Seedling Fund project, a combination of design and analysis was used to examine the feasibility of this concept. Several designs were evaluated using solid modeling, finite element analysis, and by creating prototype hardware. Then an analytical model representing the coupled electromechanical response was formulated in closed form. The model was exercised parametrically to examine the stiffness and loss factor spectra of the vibration ring, as well as simulate its damping effect in the context of a simplified driveline model. The results of this work showed that this is a viable mechanism for driveline damping, and provided several lessons for continued development.

  11. Little evidence for niche partitioning among ectomycorrhizal fungi on spruce seedlings planted in decayed wood versus mineral soil microsites.

    Science.gov (United States)

    Walker, Jennifer K M; Jones, Melanie D

    2013-12-01

    Ectomycorrhizal fungal (EMF) communities vary among microhabitats, supporting a dominant role for deterministic processes in EMF community assemblage. EMF communities also differ between forest and clearcut environments, responding to this disturbance in a directional manner over time by returning to the species composition of the original forest. Accordingly, we examined EMF community composition on roots of spruce seedlings planted in three different microhabitats in forest and clearcut plots: decayed wood, mineral soil adjacent to downed wood, or control mineral soil, to determine the effect of retained downed wood on EMF communities over the medium and long term. If downed and decayed wood provide refuge habitat distinct from that of mineral soil, we would expect EMF communities on seedlings in woody habitats in clearcuts to be similar to those on seedlings planted in the adjacent forest. As expected, we found EMF species richness to be higher in forests than clearcuts (P ≤ 0.01), even though soil nutrient status did not differ greatly between the two plot types (P ≥ 0.05). Communities on forest seedlings were dominated by Tylospora spp., whereas those in clearcuts were dominated by Amphinema byssoides and Thelephora terrestris. Surprisingly, while substrate conditions varied among microsites (P ≤ 0.03), especially between decayed wood and mineral soil, EMF communities were not distinctly different among microhabitats. Our data suggest that niche partitioning by substrate does not occur among EMF species on very young seedlings in high elevation spruce-fir forests. Further, dispersal limitations shape EMF community assembly in clearcuts in these forests.

  12. Barriers to seed and seedling survival of once-common Hawaiian palms: the role of invasive rats and ungulates.

    Science.gov (United States)

    Shiels, Aaron B; Drake, Donald R

    2015-05-27

    Mammalian herbivores can limit plant recruitment and affect forest composition. Loulu palms (Pritchardia spp.) once dominated many lowland ecosystems in Hawai'i, and non-native rats (Rattus spp.), ungulates (e.g. pigs Sus scrofa, goats Capra hircus) and humans have been proposed as major causes of their decline. In lowland wet forest, we experimentally determined the vulnerability of seeds and seedlings of two species of Pritchardia, P. maideniana and P. hillebrandii, by measuring their removal by introduced vertebrates; we also used motion-sensing cameras to identify the animals responsible for Pritchardia removal. We assessed potential seed dispersal of P. maideniana by spool-and-line tracking, and conducted captive-feeding trials with R. rattus and seeds and seedlings of both Pritchardia species. Seed removal from the forest floor occurred rapidly for both species: >50 % of Pritchardia seeds were removed from the vertebrate-accessible stations within 6 days and >80 % were removed within 22 days. Although rats and pigs were both common to the study area, motion-sensing cameras detected only rats (probably R. rattus) removing Pritchardia seeds from the forest floor. Captive-feeding trials and spool-and-line tracking revealed that vertebrate seed dispersal is rare; rats moved seeds up to 8 m upon collection and subsequently destroyed them (100 % mortality in 24-48 h in captivity). Surprisingly, seedlings did not suffer vertebrate damage in field trials, and although rats damaged seedlings in captivity, they rarely consumed them. Our findings are consistent with the hypothesis generated from palaeoecological studies, indicating that introduced rats may have assisted in the demise of native insular palm forests. These findings also imply that the seed stage of species in this Pacific genus is particularly vulnerable to rats; therefore, future conservation efforts involving Pritchardia should prioritize the reduction of rat predation on the plant recruitment stages

  13. Influence of stomatic aperture on photosynthetic activity of bean-seedlings leaves; Influencia de la apertura estomatica sobre la actividad fotosintetica de las hojas de plantas de judias

    Energy Technology Data Exchange (ETDEWEB)

    Suarez Moya, J.; Fernandez Gonzalez, J.

    1984-07-01

    The present paper contains the data of photosynthetic activity and stomatic aperture of bean-seedlings Ieaves, and the relations obtained with both results. It has been observed that the product of photosynthetic activity by the resistance; to transpiration measured by a promoter ia a constant, between some limits. (Author) 45 refs.

  14. The effect of phosphours and water deficit on phosphatase activity and proline accumulation in seedling cotyledons and roots of oilseed rape as compared to that of excised cotyledons and roots

    Directory of Open Access Journals (Sweden)

    Stanisław Flasiński

    2014-01-01

    Full Text Available Oilseed rape seedlings and excised cotyledons and roots were exposed to phosphorus and osmotic stress (-1 MPa: NaCl or PEG. The stress factors limited the growth of the seedlings and inhibited the growth of the excised roots and cotyledons. The phosphorus content in the cotyledons and roots depended on its level in the media and on the stress factors used. Phosphorus deficiency differentiated total phosphatase activity in seedling cotyledons and increased the activity in the excised cotyledons. In the excised and seedling roots, the lack of phosphorus, its deficiency and stress imposed by the addition of NaCl, caused an increase in total and specific phosphatase activity. Osmotic stress caused proline accumulation in both the seedling and excised cotyledons, but the effect of phosphorus stress was much smaller. Proline increase in seedling roots followed only after the osmotic stress caused by NaCl. The proline content in the excised roots was low. Stress factors lowered the protein content in the seedling and excised cotyledons. In both seedling and excised roots, the lowering of the protein content occurred mainly in response to osmotic stress. Kinetin modified metabolic responses in seedling cotyledons and roots. The use of in vitro culture allowed the elucidation of the tested responses. In excised cotyledons grown under stress conditions, kinetin increased the phosphorus and protein contents and lowered proline accumulation, suggesting that kinetin had the ability to overcome phosphorus and osmotic stress. The excised oilseed rape roots responded only slightly to kinetin (Drozdowska and Rogozińska 1984 and its effect was much smaller.

  15. Gene expression in plant lipid metabolism in Arabidopsis seedlings.

    Directory of Open Access Journals (Sweden)

    An-Shan Hsiao

    Full Text Available Events in plant lipid metabolism are important during seedling establishment. As it has not been experimentally verified whether lipid metabolism in 2- and 5-day-old Arabidopsis thaliana seedlings is diurnally-controlled, quantitative real-time PCR analysis was used to investigate the expression of target genes in acyl-lipid transfer, β-oxidation and triacylglycerol (TAG synthesis and hydrolysis in wild-type Arabidopsis WS and Col-0. In both WS and Col-0, ACYL-COA-BINDING PROTEIN3 (ACBP3, DIACYLGLYCEROL ACYLTRANSFERASE1 (DGAT1 and DGAT3 showed diurnal control in 2- and 5-day-old seedlings. Also, COMATOSE (CTS was diurnally regulated in 2-day-old seedlings and LONG-CHAIN ACYL-COA SYNTHETASE6 (LACS6 in 5-day-old seedlings in both WS and Col-0. Subsequently, the effect of CIRCADIAN CLOCK ASSOCIATED1 (CCA1 and LATE ELONGATED HYPOCOTYL (LHY from the core clock system was examined using the cca1lhy mutant and CCA1-overexpressing (CCA1-OX lines versus wild-type WS and Col-0, respectively. Results revealed differential gene expression in lipid metabolism between 2- and 5-day-old mutant and wild-type WS seedlings, as well as between CCA1-OX and wild-type Col-0. Of the ACBPs, ACBP3 displayed the most significant changes between cca1lhy and WS and between CCA1-OX and Col-0, consistent with previous reports that ACBP3 is greatly affected by light/dark cycling. Evidence of oil body retention in 4- and 5-day-old seedlings of the cca1lhy mutant in comparison to WS indicated the effect of cca1lhy on storage lipid reserve mobilization. Lipid profiling revealed differences in primary lipid metabolism, namely in TAG, fatty acid methyl ester and acyl-CoA contents amongst cca1lhy, CCA1-OX, and wild-type seedlings. Taken together, this study demonstrates that lipid metabolism is subject to diurnal regulation in the early stages of seedling development in Arabidopsis.

  16. Venus Flytrap Seedlings Show Growth-Related Prey Size Specificity

    Directory of Open Access Journals (Sweden)

    Christopher R. Hatcher

    2014-01-01

    Full Text Available Venus flytrap (Dionaea muscipula has had a conservation status of vulnerable since the 1970s. Little research has focussed on the ecology and even less has examined its juvenile stages. For the first time, reliance on invertebrate prey for growth was assessed in seedling Venus flytrap by systematic elimination of invertebrates from the growing environment. Prey were experimentally removed from a subset of Venus flytrap seedlings within a laboratory environment. The amount of growth was measured by measuring trap midrib length as a function of overall growth as well as prey spectrum. There was significantly lower growth in prey-eliminated plants than those utilising prey. This finding, although initially unsurprising, is actually contrary to the consensus that seedlings (traps < 5 mm do not catch prey. Furthermore, flytrap was shown to have prey specificity at its different growth stages; the dominant prey size for seedlings did not trigger mature traps. Seedlings are capturing and utilising prey for nutrients to increase their overall trap size. These novel findings show Venus flytrap to have a much more complex evolutionary ecology than previously thought.

  17. LIMING AND FERTILIZING FOR MAHOGANI (Switenia macrophylla King. SEEDLING FORMATION

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Franco Tucci

    2007-09-01

    Full Text Available The production of seedlings is one of the most important phases of the cultivation of forest species. Seedlings ofappropriate quality are fundamental in the growth and development of the species. In the production of seedlings, the substratum isfundamental for the good development of the plants. However, the subsoil in general, is acid and it contains low levels of nutritious.The acidity of the soil and the deficiency of nutrients can be corrected through liming and mineral fertilization. The objective of thepresent work was to evaluate the effect of liming and of the fertilization of the soil for the production of mahogany seedlings. Theexperiment was carried out in the period of 120 days, in the Federal University of Amazonas, UFAM. The experimental design wasrandomized complete blocks with statistical analysis in split plot. The plots were composed with eight treatments and four repetitionsand the subplots were eight sampling times of the plants. The treatments were control (natural soil, liming, corrective phosphate,fertilizing with NPK, liming + corrective phosphate, corrective phosphate + fertilizing with NPK, liming + fertilizing with NPK andliming + corrective phosphate + fertilizing with NPK. It was concluded that the associated liming and corrective phosphate and withthe fertilizing with nitrogen, phosphorous and potassium promoted the smallest levels of exchangeable aluminum and the largestlevels of calcium, magnesium, phosphorous and potassium in the soil. These levels of nutrients in the soil caused larger levels ofnutrients in the plants, providing larger growth rate. The liming, corrective phosphate and fertilizing are a fundamental practices inthe formation of mahogany seedlings.

  18. Why are there few seedlings beneath the myrmecophyte Triplaris americana?

    Science.gov (United States)

    Larrea-Alcázar, Daniel M.; Simonetti, Javier A.

    2007-07-01

    We compared the relative importance of chemical alellopathy, pruning behaviour of resident ants and other non-related agents to ant-plant mutualism for seedling establishment beneath Triplaris americana L. (Polygonaceae), a myrmecophyte plant. We also included a preliminary analysis of effects of fragmentation on these ecological processes. Seeds and seedlings of Theobroma cacao L. (Sterculiaceae) were used as the target species in all experiments. Leaf-tissue extracts of the myrmecophyte plant did not inhibit germination of cacao seeds. Resident Pseudomyrmex triplarinus Weddell (Pseudomyrmecinae) ants did not remove seeds under the canopy of their host plants. The main seed consumer was the leaf-cutting ant Atta sexdens L. (Myrmicinae). Leaves of cacao seedlings were partially or totally pruned by Pseudomyrmex ants mainly in forest fragments studied. We offer evidence pointing to the possibility that the absence of seedlings beneath Triplaris may result from effects of both ant species. We discuss the benefits of pruning behaviour for the resident ant colony and the effects of ant-ant interactions on seedling establishment beneath this ant-plant system.

  19. Growth and nutrients tenor in soursop seedlings cultivated

    Directory of Open Access Journals (Sweden)

    Rosiane de Lourdes Silva de Lima

    2009-12-01

    Full Text Available Although it is being recommended small containers, such as plastic tubes for seedling production of fruit trees, it is still necessary to study a suitable substrate for use in nursery. This experiment aimed to evaluate the effects of six organic components of the substrate on the growth and mineral composition of soursop seedlings in plastic tubes. For this purpose were evaluated six substrates: 1 Earthworm humus (HM + carbonized rice husk (CAC, 2 HM + powder coconut husk (PCCS, 3 HM + carnauba straw (BC , 4 CAC + PCCS, 5 CAC + BC and 6 PCCS + BC, being the treatments distributed in a randomized block design with four replications. Four months after sowing were evaluated the seedling growth and determined the nutrient concentration in leaves. The seedlings presented suitable vigor in substrates formed by the mixture of soil, earthworm humus, rice husk, powdered coconut husk or carnauba straw, in the volume ratio of 2:1:1. Substrates composed only by mixing soil, carbonized rice husk, powder coconut husk or carnauba straw do not allow adequate growth and nutrition in the formation of soursop seedlings.

  20. Effects of clouds and ozone on red spruce seedlings

    Energy Technology Data Exchange (ETDEWEB)

    Pier, P.A.; Thornton, F.C.; McDuffie, C. Jr. (Tennessee Valley Authority, Muscle Shoals, AL (USA))

    1989-04-01

    Potted native and Phyton-grown (Phyton Technologies) red spruce seedlings were placed in open-top field chambers constructed on Whitetop Mountain, VA (elevation 1680 m) to evaluate the effect of ozone and acid cloud deposition on seedling growth and metabolism. Chamber treatments were (1) exclusion of clouds and an approximate 50% reduction in ambient ozone, (2) ambient ozone with clouds excluded, and (3) exposure to clouds and ambient ozone (control). No differences were detected between chamber treatments for diameter growth, total chlorophyll, chl a and b, chl a/b ratio, and carotenoids. No enhancement of photosynthesis and respiration was seen in exclusion chambers for current and previous year's growth of native seedlings during the growing season. Photosynthesis of Phyton-grown seedlings was consistently higher in exclusion chambers compared to control chambers over the course of the growing season, although differences were not statistically significant. After one growing season, neither pollutant had significant effects on seedling growth and metabolism.

  1. Degraded dryland rehabilitation: boosting seedling survival using zeolitic tuff

    Science.gov (United States)

    Alhamad, Mohammad Noor; Alrbabah, Mohammad; Athamneh, Hana

    2016-04-01

    More than 90% of Jordan is broadly defined as rangelands. Most rangelands are located within the arid zone of the country. Extensive grazing occurs across much of the natural pastures resulting in serious environmental degradation of natural resources in these rangelands. Several programs were carried out for rangeland conservation and rehabilitation in the country. However, these programs face a major challenge of the low survival rate of transplanted shrub seedlings. Seeking innovative approaches to assure healthy establishment of seedling is a big challenge to achieve successful rehabilitation programs. Drought is considered one of the major problems in rehabilitation. Promoting survival and growth, using zeolitic tuff added to planting holes is suggested to be a possible solution. The experiment was conducted on a factorial arrangement within RCBD design. Two shrub species (Atriplex halimus, Atriplex nummularia) were transplanted into holes prepared with three levels of tuff treatments (mulching, mixing and control) under rainfed condition. The result showed insignificant effect of tuff on seedling survival percentage, when mixing tuff with plantation soil or adding tuff as mulch. Also, the two species showed similar survival percentages over two measured dates. However, mixing tuff with soil during hole preparation significantly enhanced seedling heights. Furthers, The Australian atriplex (Atriplex nummularia) species significantly grow higher than Atriplex halimus. The study results suggested that mixing zeoltic tuff with soil during transplantation of seedling is promising in improving the success of rangeland rehabilitation in dry areas in Jordan.

  2. Symbiotic propagation of seedlings of Cyrtopodium glutiniferum Raddi (Orchidaceae

    Directory of Open Access Journals (Sweden)

    Fernanda Aparecida Rodrigues Guimarães

    2013-09-01

    Full Text Available In nature, orchid seeds obtain the nutrients necessary for germination by degrading intracellular fungal structures formed after colonization of the embryo by mycorrhizal fungi. Protocols for asymbiotic germination of orchid seeds typically use media with high concentrations of soluble carbohydrate and minerals. However, when reintroduced into the field, seedlings obtained via asymbiotic germination have lower survival rates than do seedlings obtained via symbiotic germination. Tree fern fiber, the ideal substrate for orchid seedling acclimatization, is increasingly scarce. Here, we evaluated seed germination and protocorm development of Cyrtopodium glutiniferum Raddi cultivated in asymbiotic media (Knudson C and Murashige & Skoog and in oatmeal agar (OA medium inoculated with the mycorrhizal fungus Epulorhiza sp., using non-inoculated OA medium as a control. We also evaluated the performance of tree fern fiber, pine bark, eucalyptus bark, corncob and sawdust as substrates for the acclimatization of symbiotically propagated plants. We determined germination percentages, protocorm development and growth indices at 35 and 70 days of cultivation. Relative growth rates and the effects of substrates on mycorrhizal formation were calculated after 165 days of cultivation. Germination efficiency and growth indices were best when inoculated OA medium was used. Corncob and pine bark showed the highest percentages of colonized system roots. The OA medium inoculated with Epulorhiza sp. shows potential for C. glutiniferum seedling production. Corncob and pine bark are promising substitutes for tree fern fiber as substrates for the acclimatization of orchid seedlings.

  3. BIOACTIVE COMPOUNDS AND ANTIOXIDANT CAPACITY FROM FIVE TYPES OF SEEDLINGS

    Directory of Open Access Journals (Sweden)

    Florina Maria Copaciu

    2016-10-01

    Full Text Available After germination process, the green seedlings accumulate important quantities of bioactive compounds such as: enzymes, vitamins, minerals, chlorophylls and nutrients. The current study presents a comparison between different bioactive compounds and their antioxidant capacity, after the seedling germination and growth of five seeds (arugula, lentil, wheat, beans and mustard both on soil, in a pot (natural system, and directly on cotton wool soaked, in water (artificial system. In this study the carotenoids content and the antioxidant capacity were analysed. The data of the present study showed that the highest amount of zeaxanthin and β - carotene was found in cultivars of wheat grown in natural system, while the highest antioxidant activity was found in cultivars of wheat, lentils and beans, though in this case with no statistical differences between the systems. The results show statistical differences between the values of bioactive compounds in the five types of seedlings but also in the values obtained for the same seedlings in different systems. The best cultivars for improving the nutritional quality for human consumption are wheat seedlings followed by lentil ones.

  4. Polyphenolic Profile of Maize Seedlings Treated with 24-Epibrassinolide

    Directory of Open Access Journals (Sweden)

    Hadi Waisi

    2015-01-01

    Full Text Available High-performance thin-layer chromatography (HPTLC combined with image analysis and pattern recognition methods were used for fingerprinting of phenolic compounds present in seedlings of two maize genotypes ZP 434 (new generation hybrid, drought tolerant and ZP 704 (older generation hybrid, drought sensitive treated with different concentrations of 24-epibrassinolide. This is the first report of TLC chromatographic profile of phenolics’ mixtures in maize seed extracts influenced by brassinosteroid phytohormones. Nine samples of shoot of seedlings for the whole concentration range of phytohormones (5.2 × 10−7–5.2 × 10−15 M, one sample of root of seedlings treated with 5.2 × 10−15 M 24-epibrassinolide, and the control samples of nontreated seedlings, for both genotypes, were analyzed. Phenolic profiles of root extracts indicate the absence of more polar compounds such as phenolic acids and glycosides present in shoot of seedlings. Also, hormones applied in higher concentrations have an inhibiting effect on the content of phenolics in ZP 434. Application of chemometric methods enables characterization of particular genotype of maize according to its phenolic profile.

  5. Influence of selected Rhizoctonia solani isolates on sugar beet seedlings

    Directory of Open Access Journals (Sweden)

    Skonieczek Paweł

    2016-04-01

    Full Text Available From 2008 to 2010 the levels of sugar beet seedlings infection caused by Rhizoctonia solani were compared in laboratory tests. Seven sugar beet lines were tested: H56, H66, S2, S3, S4, S5 and S6 as well as three control cultivars: Carlos, Esperanza and Janosik. Sugar beet lines with tolerance to rhizoctoniosis and cultivars without tolerance were infected artificially by R. solani isolates: R1, R28a and R28b. These isolates belong to the second anastomosis group (AG, which is usually highly pathogenic to beet roots. The aim of the experiment was to test whether the tolerance of sugar beet genotypes to R. solani AG 2 prevents both root rot, and damping-off of seedlings, induced by the pathogen. Sugar beet lines tolerant to brown root rot in laboratory tests were significantly less sensitive to infection of the seedlings by R. solani AG 2 isolates in comparison to control cultivars. Rhizoctonia solani AG 2 isolates demonstrated considerable differences in pathogenicity against seedlings of sugar beet lines and cultivars. The strongest infection of sugar beet seedlings occurred with the isolate R28b. The greatest tolerance to infection by AG 2 isolates was found for the S5 and S3 breeding lines.

  6. Tebuconazole Regulates Fatty Acid Composition of Etiolated Winter Wheat Seedlings

    Directory of Open Access Journals (Sweden)

    A.V. Korsukova

    2016-05-01

    Full Text Available The fatty acid composition of shoots of unhardened and hardened to cold etiolated winter wheat seedlings grown from seeds treated with tebuconazole-based protectant «Bunker» (content of tebuconazole 60 grams per liter, g/L, and the seedlings frost resistance has been studied. It is shown that treatment of winter wheat seeds by «Bunker» preparation (1,5 microliter per gram of seeds, µl/g is accompanied by an increase of the fatty acids unsaturation in the shoots and increase of the seedlings frost resistance (–8°C, 24 h. The most pronounced decrease in the content of saturated palmitic acid and increase in the content of unsaturated α-linolenic acid were observed during cold hardening of winter wheat seedlings grown from seeds treated by tebuconazole-based protectant. It is concluded that the seeds treatment with tebuconazole-based protectant causes changes of fatty acid composition of winter wheat seedlings to increase their frost resistance.

  7. The effects of H2SO4 and (NH42SO4 treatments on the chemistry of soil drainage water and pine seedlings in forest soil microcosms

    Directory of Open Access Journals (Sweden)

    M. I. Stutter

    2004-01-01

    Full Text Available An experiment comparing effects of sulphuric acid and reduced N deposition on soil water quality and on chemical and physical growth indicators for forest ecosystems is described. Six H2SO4 and (NH42SO4 treatment loads, from 0 – 44 and 0 – 25 kmolc ha-1 yr-1, respectively, were applied to outdoor microcosms of Pinus sylvestris seedlings in 3 acid to intermediate upland soils (calc-silicate, quartzite and granite for 2 years. Different soil types responded similarly to H2SO4 loads, resulting in decreased leachate pH, but differently to reduced N inputs. In microcosms of calc-silicate soil, nitrification of NH4 resulted in lower pH and higher cation leaching than in acid treatments. By contrast, in quartzite and granite soils, (NH42SO4 promoted direct cation leaching, although leachate pH increased. The results highlighted the importance of soil composition on the nature of the cations leached, the SO4 adsorption capacities and microbial N transformations. Greater seedling growth on calc-silicate soils under both treatment types was related to sustained nutrient availability. Reductions in foliar P and Mg with higher N treatments were observed for seedlings in the calc-silicate soil. There were few treatment effects on quartzite and granite microcosm tree seedlings since P limitation precluded seedling growth responses to treatments. Hence, any benefits of N deposition to seedlings on quartzite and granite soils appeared limited by availability of co-nutrients, exacerbated by rapid depletion of soil exchangeable base cations. Keywords: acidification, manipulation, nitrogen, ammonium, deposition, soil, drainage, pine, microcosms, forest

  8. Current limiters

    Energy Technology Data Exchange (ETDEWEB)

    Loescher, D.H. [Sandia National Labs., Albuquerque, NM (United States). Systems Surety Assessment Dept.; Noren, K. [Univ. of Idaho, Moscow, ID (United States). Dept. of Electrical Engineering

    1996-09-01

    The current that flows between the electrical test equipment and the nuclear explosive must be limited to safe levels during electrical tests conducted on nuclear explosives at the DOE Pantex facility. The safest way to limit the current is to use batteries that can provide only acceptably low current into a short circuit; unfortunately this is not always possible. When it is not possible, current limiters, along with other design features, are used to limit the current. Three types of current limiters, the fuse blower, the resistor limiter, and the MOSFET-pass-transistor limiters, are used extensively in Pantex test equipment. Detailed failure mode and effects analyses were conducted on these limiters. Two other types of limiters were also analyzed. It was found that there is no best type of limiter that should be used in all applications. The fuse blower has advantages when many circuits must be monitored, a low insertion voltage drop is important, and size and weight must be kept low. However, this limiter has many failure modes that can lead to the loss of over current protection. The resistor limiter is simple and inexpensive, but is normally usable only on circuits for which the nominal current is less than a few tens of milliamperes. The MOSFET limiter can be used on high current circuits, but it has a number of single point failure modes that can lead to a loss of protective action. Because bad component placement or poor wire routing can defeat any limiter, placement and routing must be designed carefully and documented thoroughly.

  9. THE EFFECT OF MAGNETIC LIQUIDS IN SOME TREE SEEDLINGS

    Directory of Open Access Journals (Sweden)

    Ioan Creanga

    2005-08-01

    Full Text Available The seedlings of two tree species, the black poplar hybrid (Populus canadiensis Moench. and the pedunculate oak (Quercus robur L., among the most important for the temperate region, were treated with various concentrations of oil-ferrofluid based on natural hydrocarbons. The experiment has revealed the ferrofluid influence on the assimilatory pigments as well as on the nucleic acids (spectral measurements in young plantlets aged of 3 months. It was found that the levels of assimilatory pigments are generally diminished though the ratio chlorophyll a/chlorophyll b is generally enhanced for ferrofluid samples suggesting the seedlings sensitivity to the chemical and magnetic stimuli consistent with the ferrofuid addition. The LHC II system (Light Harvesting Complex II sensitivity to external factors might be associated with the ferrofluid influence on the young seedlings photosynthesis.

  10. Nitrogen ion utilization by tulip poplar (Liriodendron tulipifera L. ) seedlings

    Energy Technology Data Exchange (ETDEWEB)

    Mann, L.K.

    1982-01-01

    Growth responses of one-year-old tulip poplar seedlings were determined for different nitrogen sources (HN/sub 4/NO/sub 3/, NH+/sub 4/, NO-/sub 3/, no nitrogen) at 336 ppm N in nutrient culture. At the end of three months, there were no significant differences in growth observed among treatments in terms of stem elongation, leaf area, and leaf size. After four months, however, seedlings of the NH/sub 4/NO/sub 3/ treatment exhibited significantly (P<0.05) greater growth (final weight gain and stem elongation) than all other nitrogen sorces. Growth was slightly less for the NO-/sub 3/ treatment plants, but compared with NH+/sub 4/ and no nitrogen treatment, both NH/sub 4/NO/sub 3/ and NO-/sub 3/ treatments exhibited significantly greater growth responses. NO-/sub 3/ is recommended as the sole nitrogen source, especially for small seedlings of tulip poplar.

  11. Seedling establishment of Ferocactus acanthodes in relation to drought

    Energy Technology Data Exchange (ETDEWEB)

    Jordan, P.W.; Nobel, P.S.

    1981-08-01

    The 30 smallest seedlings of Ferocactus acanthodes (Lem.) Britton and Rose (Cactaceae) at a canyon site in the northwestern Sonoran desert averaged 2.5 cm in height. Based on field studies of CO/sub 2/ exchange throughout the year, the estimated time of their germination was late summer 1976. To explan why so little establishment occurred in recent years, the length of lethal drought for seedlings of various ages was calculated from the seedling geometry (volume-to-surface ratio), dehydration tolerance, and transpiration rates. Individual years were identified which had sufficiently long growing seasons relative to the length of the subsequent droughts to allow establishment. Eight of the last 18 y were found to be suitable for establishment of F. acanthodes, the latest year being 1976.

  12. Growth response of Pinus densiflora seedlings inoculated with three indigenous ectomycorrhizal fungi in combination

    OpenAIRE

    Dalong,M; Luhe,W; Guoting,Y; M Liqiang; Chun,L

    2011-01-01

    Pinus densiflora seedlings were inoculated with three indigenous ectomycorrhizal fungi (Cenococcum geophilum, Rhizopogon roseolus and Russula densifolia) in single-, two-, and three-species treatments. After 8 months, the colonization rates of each ectomycorrhizal species, seedling growth and the nutrition were assessed in each treatment. P. densiflora seedlings inoculated with different ECM species composition showed an increase in height and basal diameter and improved seedling root and sho...

  13. Recruitment of a mast-fruiting, bird-dispersed tree: Bridging frugivore activity and seedling establishment

    OpenAIRE

    Herrera, Carlos M.; Jordano, Pedro; López-Soria, L.; Amat, Juan A.

    1994-01-01

    The recruitment of Phillyrea latifolia L. (Oleaceae), a bird-dispersed tree of Mediterranean forest, is described. Fruit removal by birds, seed rain, post-dispersal seed predation, seed germination, and seedling emergence, survival, and establishment were studied. The main objective was testing whether seed dispersal by birds produced a predictable seedling shadow as a result of coupled patterns of seed rain, seedling emergence, and seedling establishment. P. latifolia is a mast-fruiting spec...

  14. Study on the Export Competitiveness of China’s Flower Seedlings

    Institute of Scientific and Technical Information of China (English)

    Jie; ZHOU

    2015-01-01

    This paper introduces the " National Diamond Model" and reviews the literature concerning the export of flower seedlings.Then it analyzes the production and export of Chinese flower seedlings,as well as the factors( factor endowments,foreign demand,related industries and industrial organization) influencing the production of Chinese flower seedlings based on Diamond Model.Finally,this paper puts forth the recommendations for the enhancement of the export competitiveness of Chinese flower seedlings.

  15. Impact of climate change, seedling type and provenance on the risk of damage to Norway spruce (Picea abies (L.) Karst.) seedlings in Sweden due to early summer frosts

    Energy Technology Data Exchange (ETDEWEB)

    Langvall, Ola (Swedish Univ. of Agricultural Sciences, Unit for Field-based Forest Research, Asa Forest Research Station, Lammhult (Sweden))

    2011-04-15

    A model including site-specific microclimate-affecting properties of a forest regeneration area together with seedling characteristics was used to evaluate the accumulated risk of frost damage to Norway spruce (Picea abies (L.) Karst.) seedlings. Climate change in Sweden was simulated on the basis of the regional climate model RCA3. The daily average temperature, the driving factor for bud burst in the model, was adjusted using the difference between the mean of the climate model data for the years 1961-1990 and 2036-2065. The model was run for a highly frost prone, clear-cut site in which bare-rooted Norway spruce seedlings of mid-Swedish provenance were planted. Alternate runs were conducted with data for containerized seedlings and seedlings of Belarusian origin. The study showed that bud burst will occur at earlier dates throughout Sweden in the period 2036-2065 if the climate changes according to either of the climate scenarios examined, compared to the reference period 1961-1990. Furthermore, the risk of damage to Norway spruce seedlings as a result of frost events during summer will increase in southern Sweden and be unaffected or decrease in northern Sweden. The risk of frost damage was exacerbated in containerized seedlings, while the risk was lower for the seedlings of Belarusian provenance when compared with bare-rooted seedlings or seedlings of mid-Swedish origin

  16. Role of geographical provenance in the response of silver fir seedlings to experimental warming and drought.

    Science.gov (United States)

    Matías, Luis; Gonzalez-Díaz, Patricia; Quero, José L; Camarero, J Julio; Lloret, Francisco; Jump, Alistair S

    2016-10-01

    Changes in climate can alter the distribution and population dynamics of tree species by altering their recruitment patterns, especially at range edges. However, geographical patterns of genetic diversity could buffer the negative consequences of changing climate at rear range edges where populations might also harbour individuals with drought-adapted genotypes. Silver fir (Abies alba Mill.) reaches its south-western distribution limit in the Spanish Pyrenees, where recent climatic dieback events have disproportionately affected westernmost populations. We hypothesized that silver fir populations from the eastern Pyrenees are less vulnerable to the expected changing climate due to the inclusion of drought-resistant genotypes. We performed an experiment under strictly controlled conditions simulating projected warming and drought compared with current conditions and analysed physiology, growth and survival of silver fir seedlings collected from eastern and western Pyrenean populations. Genetic analyses separated eastern and western provenances in two different lineages. Climate treatments affected seedling morphology and survival of both lineages in an overall similar way: elevated drought diminished survival and induced a higher biomass allocation to roots. Increased temperature and drought provoked more negative stem water potentials and increased δ(13)C ratios in leaves. Warming reduced nitrogen concentration and increased soluble sugar content in leaves, whereas drought increased nitrogen concentration. Lineage affected these physiological parameters, with western seedlings being more sensitive to warming and drought increase in terms of δ(13)C, nitrogen and content of soluble sugars. Our results demonstrate that, in A. alba, differences in the physiological response of this species to drought are also associated with differences in biogeographical history.

  17. Organic Molecules from Biochar Leacheates Have a Positive Effect on Rice Seedling Cold Tolerance.

    Science.gov (United States)

    Yuan, Jun; Meng, Jun; Liang, Xiao; E, Yang; Yang, Xu; Chen, Wenfu

    2017-01-01

    Biochar is known to have a number of positive effects on plant ecophysiology. However, limited research has been carried out to date on the effects and mechanisms of biochar on plant ecophysiology under abiotic stresses, especially responses to cold. In this study, we report on a series of experiments on rice seedlings treated with different concentrations of biochar leacheates (between 0 and 10% by weight) under cold stress (10°C). Quantitative real-time PCR (qRT-PCR) and cold-resistant physiological indicator analysis at low temperatures revealed that the cold tolerance of rice seedlings increased after treatment with high concentrations of biochar leacheates (between 3 and 10% by weight). Results also show that the organic molecules in biochar leacheates enhance the cold resistance of plants when other interference factors are excluded. We suggest that the positive influence of biochar on plant cold tolerance is because of surface organic molecules which likely function by entering a plant and interacting with stress-related proteins. Thus, to verify these mechanisms, this study used gas chromatography-mass spectrometry (GC-MS) techniques, identifying 20 organic molecules in biochar extracts using the National Institute of Standards and Technology (NIST) library. Further, to illustrate how these organic molecules work, we utilized the molecular docking software Autodock to show that the organic molecule 6-(Methylthio)hexa-1,5-dien-3-ol from biochar extracts can dock with the stress-related protein zinc-dependent activator protein (ZAP1). 6-(Methylthio)hexa-1,5-dien-3-ol has a similar binding mode with the ligand succinic acid of ZAP1. It can be inferred that the organic molecule identified in this study performs the same function as the ZAP1 ligand, stimulating ZAP1 driving cold-resistant functions, and enhancing plant cold tolerance. We conclude that biochar treatment enhances cold tolerance in rice seedlings via interactions between organic molecules and

  18. Comparative analysis of MAMP-induced calcium influx in Arabidopsis seedlings and protoplasts.

    Science.gov (United States)

    Maintz, Jens; Cavdar, Meltem; Tamborski, Janina; Kwaaitaal, Mark; Huisman, Rik; Meesters, Christian; Kombrink, Erich; Panstruga, Ralph

    2014-10-01

    Rapid transient elevation of cytoplasmic calcium (Ca(2+)) levels in plant cells is an early signaling event triggered by many environmental cues including abiotic and biotic stresses. Cellular Ca(2+) levels and their alterations can be monitored by genetically encoded reporter systems such as the bioluminescent protein, aequorin. Employment of proteinaceous Ca(2+) sensors is usually performed in transgenic lines that constitutively express the reporter construct. Such settings limit the usage of these Ca(2+) biosensors to particular reporter variants and plant genetic backgrounds, which can be a severe constraint in genetic pathway analysis. Here we systematically explored the potential of Arabidopsis thaliana leaf mesophyll protoplasts, either derived from a transgenic apoaequorin-expressing line or transfected with apoaequorin reporter constructs, as a complementary biological resource to monitor cytoplasmic changes of Ca(2+) levels in response to various biotic stress elicitors. We tested a range of endogenous and pathogen-derived elicitors in seedlings and protoplasts of the corresponding apoaequorin-expressing reporter line. We found that the protoplast system largely reflects the Ca(2+) signatures seen in intact transgenic seedlings. Results of inhibitor experiments including the calculation of IC50 values indicated that the protoplast system is also suitable for pharmacological studies. Moreover, analyses of Ca(2+)signatures in mutant backgrounds, genetic complementation of the mutant phenotypes and expression of sensor variants targeted to different subcellular localizations can be readily performed. Thus, in addition to the prevalent use of seedlings, the leaf mesophyll protoplast setup represents a versatile and convenient tool for the analysis of Ca(2+) signaling pathways in plant cells.

  19. Genetics of drought tolerance at seedling and maturity stages in Zea mays L

    Energy Technology Data Exchange (ETDEWEB)

    Khan, N.H.; Ahsan, M.; Naveed, M.; Sadaqat, H.A.; Javed, I.

    2016-11-01

    Shortage of irrigation water at critical growth stages of maize is limiting its production worldwide. Breeding drought-tolerant cultivars is one possible solution while identification of potential genotypes is crucial for genetic improvement. To assess genetic variation for seedling-stage drought tolerance, we tested 40 inbred lines in a completely randomized design under glasshouse conditions. From these, two contrasting inbred lines were used to develop six basic generations (P1, P2, F1, F2, BC1F1, BC2F2). These populations were then evaluated in a triplicated factorial randomized complete block design under non-stressed and drought-stressed conditions. For statistical analyses, a nested block design was employed to ignore the replication effects. Significant differences (p=0.01) were recorded among the genotypes for investigated seedling-traits. Absolute values of fresh root length, fresh root weight, and dry root weight lead to select two genotypes, one tolerant (WFTMS) and one susceptible (Q66). Estimates of heritability, genetic advance, and genotypic correlation coefficients were higher and significant for most of the seedling-traits. Generation variance analysis revealed additive gene action. Narrow-sense heritability [F2 = 65; F8 = 79] revealed the same results. Generation mean analysis signified additive genetic effects in the inheritance of cob girth, non-additive for plant height, grains per ear row and grain yield per plant, and environmental for ear leaf area, cob length, grain rows per ear, biomass per plant, and 100-grain weight under drought-stressed conditions. For conferring drought-tolerance in maize, breeders can adopt the recombinant breeding strategy to pyramid the desirable genes. (Author)

  20. The Effect of vermicompost on salt tolerance of bean seedlings (Phaseolus vulgaris L.

    Directory of Open Access Journals (Sweden)

    A. Beyk Khurmizi

    2016-04-01

    Full Text Available In the recent years, increasing production of waste as a result of population growth, increased food consumption, industrial development and urbanization growth, is regarded as a serious challenge. Vermicompost, as an end product of urban waste recycling with proper physicochemical features, can play an effective role in plant growth and development and also in reducing harmful effects of various environmental stresses on plants. For this purpose, a study with the aim of investigating the effects of vermicompost and salinity interactions on morphological traits of bean (Phaseolus vulgaris L. cv. Light Red Kidney seedlings was performed. The experiment was conducted based on a randomized complete block design, including five different volumetric ratios of vermicompost and sand (0:100; 10:90; 25:75; 50:50 and 75:25, and four levels of salinity (30, 60, 90 and 120 mmol l-1 NaCl, equal to 2.75, 5.50, 8.25 and 11 deciSiemens per meter (dS/m respectively, along with control (0.00, in three replications. Seeds were cultured in plastic pots and sampling of seedlings was done after 28 days. The results showed that in an environment without stress, vermicompost had significant effect (p ≤ 0.05 on the stem length, internodes number, area and dry weight of leaves, diameter, dry weight and total roots length, while having no significant effect on stem dry weight. The interaction between salinity and vermicompost has significant effect on the stem length, internodes number, the area and dry weight of leaves and dry weight of roots but no significant effect was observed on the stem dry weight, diameter and total roots length. Thus, in the low levels of salinity, all ratios of vermicompost and in high levels of salinity, high ratios of vermicompost can limit the negative effects of salinity on bean seedlings.

  1. Genotypic effects of fertilization on seedling sweetgum biomass allocation, N uptake, and N use efficiency.

    Science.gov (United States)

    Chang, S X; Robison, D J

    2001-10-23

    Screening and selecting tree genotypes that are responsive to N additions and that have high nutrient use efficiencies can provide better genetic material for short-rotation plantation establishment. A pot experiment was conducted to test the hypotheses that (1) sweetgum ( Liquidambar styraciflua L.) families have different patterns in biomass production and allocation, N uptake, and N use efficiency (NUE), because of their differences in growth strategies, and (2) sweetgum families that are more responsive to N additions will also have greater nutrient use efficiencies. Seedlings from two half-sib families (F10022 and F10023) that were known to have contrasting responses to fertility and other stress treatments were used for an experiment with two levels of N (0 vs. 100 kg N/ha equivalent) and two levels of P (0 vs. 50 kg P/ha equivalent) in a split-plot design. Sweetgum seedlings responded to N and P treatments rapidly, with increases in both size and biomass production, and those responses were greater with F10023 than with F10022. Growth response to N application was particularly strong. N and P application increased the proportional allocation of biomass to leaves. Under increased N supply, P application increased foliar N concentration and content, as well as total N uptake by the seedlings. However, NUE was decreased by N addition and was higher in F10023 than in F10022 when P was not limiting. A better understanding of genotype by fertility interactions is important in selecting genotypes for specific site conditions and for optimizing nutrient use in forestry production.

  2. Genotypic Effects of Fertilization on Seedling Sweetgum Biomass Allocation, N Uptake, and N Use Efficiency

    Directory of Open Access Journals (Sweden)

    Scott X. Chang

    2001-01-01

    Full Text Available Screening and selecting tree genotypes that are responsive to N additions and that have high nutrient use efficiencies can provide better genetic material for short-rotation plantation establishment. A pot experiment was conducted to test the hypotheses that (1 sweetgum (Liquidambar styraciflua L. families have different patterns in biomass production and allocation, N uptake, and N use efficiency (NUE, because of their differences in growth strategies, and (2 sweetgum families that are more responsive to N additions will also have greater nutrient use efficiencies. Seedlings from two half-sib families (F10022 and F10023 that were known to have contrasting responses to fertility and other stress treatments were used for an experiment with two levels of N (0 vs. 100 kg N/ha equivalent and two levels of P (0 vs. 50 kg P/ha equivalent in a split-plot design. Sweetgum seedlings responded to N and P treatments rapidly, with increases in both size and biomass production, and those responses were greater with F10023 than with F10022. Growth response to N application was particularly strong. N and P application increased the proportional allocation of biomass to leaves. Under increased N supply, P application increased foliar N concentration and content, as well as total N uptake by the seedlings. However, NUE was decreased by N addition and was higher in F10023 than in F10022 when P was not limiting. A better understanding of genotype by fertility interactions is important in selecting genotypes for specific site conditions and for optimizing nutrient use in forestry production.

  3. Gleditschia amorphoides Taub. SEEDLING GROWTH PRODUCED UNDER DIFFERENT SUBSTRATES

    Directory of Open Access Journals (Sweden)

    Michele Fernanda Bortolini

    2012-03-01

    Full Text Available http://dx.doi.org/10.5902/198050985077Locally known as sucará, Gleditschia amorphoides besides being a woody species, it can be used in plantations used for the rehabilitation of degraded areas. Therefore, the objective of the current work was to evaluate the seedling growth, over time produced under different substrates. The experiment was made at the UNIOESTE nursery in Santa Helena district, in Paraná state, using direct sowing in polypropylene sized tubes of 200cm3. Different mixtures were tested as substrate, containing Plantmax®, decomposed leaves residue, sawdust, litter, cattle manure and carbonized rice hulls. Monthly, during 180 days, evaluations of height and diameter of the lap were made, analyzed by a completely randomized design, with 5 replicates of 12 seedlings, in a subdivided plot scheme in time. At the end of the experiment, root dry mass and aerial part dry mass, the relation between these variables and the leaf area, were determined for 12 seedlings each treatment, in a completely randomized design. The water-holding capacity, substrate total porosity and pH were determined. All data were submitted to variance analysis and the means compared by the Tukey’s test. In general, all substrates provided gradual increase in the diameter of the lap and seedling height. Seedlings produced in 50% of Plantmax®+ 20% of carbonized rice hulls + 30% of cattle manure provided bigger diameter (4,5mm and seedlings height (22,7 cm, as well as bigger root dry mass and aerial part dry mass (0,88 and 1,62g, respectively followed by seedlings produced in 50% of Plantmax®+ 20% of carbonized rice hulls + 20% of cattle manure + 10% leaf residue with 4,0mm and 19,7mm, for diameter and height respectively. In these experimental conditions, Sucará seedlings produced in 50% of Plantmax®+ 20% of carbonized rice hulls + 30% of cattle manure presented bigger growth.

  4. Transport of calcium in seedlings and cuttings of mung bean

    Energy Technology Data Exchange (ETDEWEB)

    Broadbent, W.

    1984-01-01

    At germination, a very small proportion of stored calcium is mobilized to the axis in the absence of exogenous supplies of calcium. There is no evidence for transport in phloem since exported calcium does not enter the seedling root. /sup 45/Calcium is not redistributed when applied to cotyledons at germination of leaves of seedlings. A subsequent large addition of unlabelled calcium promotes a small redistribution from leaves. Triiodobenzoic acid (TIBA), applied to leaves, leads to a small reduction in calcium accumulation but does not effect redistribution. Auxin is without effect and auxin plus TIBA promotes accumulation. These results are discussed in relation to possible extracellular binding sites for calcium.

  5. Seedling Growth and Physiological Responses of Sixteen Eucalypt Taxa under Controlled Water Regime

    Directory of Open Access Journals (Sweden)

    Paulo H. M. Silva

    2016-05-01

    Full Text Available We assessed growth and physiological responses of Eucalyptus and Corymbia species to water limitation aiming to widen possibilities for plantations in dry climatic conditions. We selected 16 taxa: 4 Corymbia and 12 Eucalyptus species from the Subgenera Symphyomyrtus. Seedlings were evaluated from 100 to 170 days after sowing. Growth and physiological traits showed significant differences among taxa and between two levels of water availability. Water limitation significantly impacted biomass production and physiological characteristics, however in different levels. Leaf area and biomass production decreased 15%–48% under water limitation among taxa. Eucalyptus moluccana, CCV 2, and VM1 (drought tolerant clone showed the largest decrease in leaf area. Transpiration across taxa decreased 30%–57% and photosynthesis 14%–48% under water limited condition. Taxa from cold environments were less responsive in leaf area reduction under water limitation, and taxa from Exsertaria section showed lower reduction in photosynthesis (E. camaldulensis showed the lowest reduction. Responses to water limitation are related to the environment of origin. E. molucana, the only Adnataria species from a high precipitation region (>1500 mm year−1, was one of the most sensitive in reduction of biomass production, different behavior from the other Adnataria species, originated in regions with rainfall <750 mm year−1. Water limitation increased leaf-level water use efficiency by 18% on average, 8% in E. longirostrata, and 28% in E. camaldulensis, E. brassiana, and E. crebra. Growth and physiological responses observed show the potential of different eucalypts taxa to tolerate water limited environments.

  6. Common arbuscular mycorrhizal networks amplify competition for phosphorus between seedlings and established plants

    DEFF Research Database (Denmark)

    Merrild, Marie Porret; Ambus, Per; Rosendahl, Søren;

    2013-01-01

    ) seedlings grew into established networks of Rhizophagus irregularis and cucumber (Cucumis sativus) in two experiments. One experiment studied seedling uptake of 32P in the network in response to cutting of cucumber shoots; the other analysed seedling uptake of P and nitrogen (N) in the presence of intact...

  7. Effects of vesicular-arbuscular mycorrhizae and seed source on nursery-grown black walnut seedlings

    Science.gov (United States)

    B. L. Brookshire; H. E. Garrett; T. L. Robison

    2003-01-01

    A nursery study was established in Missouri to evaluate the effects of endomycorrhizal inoculation and seed source on the growth of black walnut seedlings. Inoculation, in general, resulted in seedlings with significantly larger sturdiness quotients. Glomus intraradicies was found to produce larger seedlings than Glomus etunicatus...

  8. Effects of Toxic Levels of Aluminium on Seedling Parameters of Rice under Hydroponic Culture

    Institute of Scientific and Technical Information of China (English)

    Bidhan ROY; Sanjib BHADRA

    2014-01-01

    The presence of Al in the rhizosphere of rice in acid soil restricts root growth and significantly reduces crop productivity. In this study, the effects of Al (30, 60 and 90 µg/mL) on seedling root growth, number of primary roots per seedling, seedling shoot length, number of leaves per seedling, seedling fresh weight, and seedling dry weight were studied. Rice genotypes were classified into three different classes, namely, tolerant, moderately tolerant, and susceptible, based on root tolerance index. The method of hydroponic culture was modified, and elaborated in the text. Toxic levels of Al in nutrient solution significantly decreased seedling root growth, number of primary roots, seedling shoot length, number of leaves per seedling, seedling fresh weight, and seedling dry weight. Few genotypes showed longer root length at 30 µg/mL Al in nutrient solutions compared with the control. High levels of Al in nutrient solutions were highly toxic for rice seedlings. Based on root tolerance index, Radhunipagal, Gobindobhog, Badshabhog, Kalobhog, UBKVR-11, UBKVR-16, UBKVR-18, Khasha and IVT4007-B were classified as tolerant genotypes, and these genotypes may be used as donors for breeding of Al-toxicity tolerance.

  9. Growth and water relations of seedlings of two subspecies of Eucalyptus globulus.

    Science.gov (United States)

    Wang, D; Bachelard, E P; Banks, J C

    1988-06-01

    Seedlings of Eucalyptus globulus Labill subsp. globulus grown in soil in pots in the greenhouse grew faster than seedlings of E. globulus subsp. bicostata, and responded better to added nutrients and water. However, water stress caused a greater reduction in the growth of shoots and roots, and in the root/shoot ratios of fertilized seedlings of subsp. globulus than in those of bicostata. More leaf surface wax was produced by seedlings grown in the presence of fertilizer and an adequate supply of water than by seedlings subjected to nutrient or water stress. Despite larger amounts of leaf surface wax, seedlings of subsp. bicostata had higher epidermal conductances than seedlings of subspecies globulus. However, epidermal conductances were reduced more by water stress and by fertilization in seedlings of subsp. bicostata than in subsp. globulus. Tissue osmotic potentials at full and zero turgor were reduced by water stress only in seedlings of subsp. bicostata and were increased by fertilizer only in seedlings of subsp. globulus. The results indicate that although seedlings of subsp. globulus have inherently higher growth rates, seedlings of subsp. bicostata are better adapted to drought.

  10. Comparative growth of black spruce container seedlings grown in worm-casting-amended soilless media

    Energy Technology Data Exchange (ETDEWEB)

    Menes, P.A.; Colombo, S.J.

    1992-01-01

    This study compared the morphology of containerized black spruce seedlings grown in fertilized and non-fertilized worm- casting-amended media to seedlings grown in a non-amended fertilized peat-vermiculite mix. The comparison was made to determine if various media amended with castings could produce seedlings equivalent to those produced using a standard nursery growing medium.

  11. INFLUENCE OF A PERIOD OF ARTIFICIAL LIGHTING ON FORMATION OF LETTUCE SEEDLINGS

    Directory of Open Access Journals (Sweden)

    Abyan M. V.

    2014-09-01

    Full Text Available The article presents a research of reaction of seedlings of lettuce on light duration with sodium lamps when grown in a greenhouse. It was shown that in winter conditions of the Krasnodar Region the intensity of natural light to produce quality seedlings of lettuce is insufficient and additional lighting has a significant influence on the morphology of lettuce seedlings

  12. Antioxidants and anti-stress compounds improve the survival of cryopreserved Arabidopsis seedlings

    Science.gov (United States)

    Cryopreservation is a safe and cost-effective tool for the long-term storage of plant germplasm. Successful cryopreservation depends on suitable cryoprotection protocol. In Arabidopsis seedlings cryopreservation, the growth ability could be partly restored in 60-h seedlings, whereas 72-h seedlings d...

  13. Four different Phytophthora species that are able to infect Scots pine seedlings in laboratory conditions

    Directory of Open Access Journals (Sweden)

    Tkaczyk Miłosz

    2016-09-01

    Full Text Available To investigate susceptibility of young Scots pine seedlings to four Phytophthora species: Phytophthora cactorum, Phytophthora cambivora, Phytophthora plurivora and Phytophthora pini; seven-day-old seedlings of Scots pine (15 seedlings per experiment were infected using agar plugs of the respective species. Control group also consisted of 15 seedlings and was inoculated with sterile agar plugs. Results unambiguously show that after 4.5 days, all seedlings show clear signs of infection and display severe symptoms of tissue damage and necrosis. Moreover, three and two seedlings in the P. cactorum and P. cambivora infected seedlings groups, respectively, collapsed. The length of largest necrosis measured 13.4±3.90 mm and was caused by P. cactorum. To rule out any putative contamination or infection by secondary pathogens, re-isolations of pathogens from infection sites were performed and were positive in 100% of plated pieces of infected seedlings. All re-isolations were, however, negative in the case of the control group. Detailed microscopic analyses of infected tissues of young seedlings confirmed the presence of numerous Phytophthora species inside and on the surface of infected seedlings. Therefore, our results suggest Phytophthora spp. and mainly P. cactorum and P. cambivora as aggressive pathogens of Scots pine seedlings and highlight a putative involvement of these species in the damping off of young Scots pine seedlings frequently observed in forest nurseries.

  14. Sensitivity of limber pine (Pinus flexilis) seedling physiology to elevation, warming, and water availability across a timberline ecotone

    Science.gov (United States)

    Moyes, A. B.; Castanha, C.; Ferrenberg, S.; Germino, M. J.; Kueppers, L. M.

    2010-12-01

    Treelines occur where environmental gradients such as temperature become limiting to tree establishment, and are thus likely to respond to changes in climate. We collected gas exchange, water potential, and fluorescence measurements from limber pine (Pinus flexilis) seedlings planted into experimental plots at three elevations at Niwot Ridge, Colorado, ranging from within forest to alpine. At each site seeds from local high- and low-elevation populations were sewn into replicated and controlled watering and infrared heating treatment plots. Heating led to earlier snowmelt, germination, and soil moisture availability in spring; higher soil surface temperatures throughout the growing season; and drier soils in late summer. Assimilation rates in all plots were most strongly associated with soil moisture availability following germination, and decreased as soils dried over the growing season. Intrinsic water use efficiency was consistent for the two source populations, but there was evidence that individuals germinating from high-elevation seeds respired more per unit carbon assimilated under our experimental conditions. Chlorophyll fluorescence showed no evidence of photoinhibition in any elevation or treatment category. Earlier soil moisture depletion in heated plots was associated with lower midday stem water potentials and reduced stomatal conductance in August. Our watering treatments did not substantially reduce apparent midsummer water stress. Seedlings in ambient temperature plots had higher assimilation rates in August than those in heated plots, but also greater carbon loss via photorespiration. Moisture limitation in heated plots in summer interacted with variability in afternoon sun exposure within plots, and qualitative observations suggested that many seedlings were killed by desiccation and heat girdling at all elevations. While early snowmelt and moisture availability in heated plots provided a longer growing season, earlier reduction of soil moisture

  15. Limited Neutrality

    DEFF Research Database (Denmark)

    Nielsen, Morten Ebbe Juul

    2006-01-01

    Article Concerning the prospect of a kind of limited neutrality in place of the standard liberal egalitarian "neutrality of justification."......Article Concerning the prospect of a kind of limited neutrality in place of the standard liberal egalitarian "neutrality of justification."...

  16. Limiting Skepticism

    DEFF Research Database (Denmark)

    Hendricks, Vincent Fella; Symons, John

    2011-01-01

    Skeptics argue that the acquisition of knowledge is impossible given the standing possibility of error. We present the limiting convergence strategy for responding to skepticism and discuss the relationship between conceivable error and an agent’s knowledge in the limit. We argue that the skeptic...

  17. Limited Neutrality

    DEFF Research Database (Denmark)

    Nielsen, Morten Ebbe Juul

    2006-01-01

    Article Concerning the prospect of a kind of limited neutrality in place of the standard liberal egalitarian "neutrality of justification."......Article Concerning the prospect of a kind of limited neutrality in place of the standard liberal egalitarian "neutrality of justification."...

  18. Effects of saline-alkaline stress on seed germination and seedling growth of Sorghum bicolor (L.) Moench.

    Science.gov (United States)

    Zhao, Yanyun; Lu, Zhaohua; He, Lei

    2014-08-01

    In order to study the adaptation ability of sweet sorghum (Sorghum bicolor L. Moench) in the Yellow River Delta, the sweet sorghum variety Mart was used in this study to determine the roles of different saline-alkaline ratio stress treatment during seed germination to seedling stage. The results showed that Na+ concentration had a significant impact on the seed germination, seedling growth, and plant survival of sweet sorghum. Increasing Na+ concentration led to a decline in germination rate, final germination percentage, survival percentage, plant height, and dry weight per plant, a prolonged mean time of germination, as well as loss of improvement effect of low-Na+ concentration. The interaction effect of Na+ concentration and pH on the mean time of germination and germination rate was not significant (psorghum was resistant to the pH stress (≥9.04) when the Na+ concentration was below 100 mM. When suffered from the saline-alkaline stress, the seedling of sweet sorghum was characterized by ecological adaptive features, such as decreased stem ratio and chlorophyll b content in leaves and increased root ratio and chlorophyll a content, in order to maintain the uptakes of water and nutrient, and carbon assimilation. When the stress intensified, the lipid oxidation products, e.g., malondialdehyde (MDA), increased in sweet sorghum seedlings. However, the increasing of soluble protein content and antioxidant enzyme activity (superoxide dismutase (SOD), guaiacol peroxidase (POD), and gatalase (CAT)) was only founded in neutral low-Na+ concentration treatment (A1), which indicated that high-salt concentration and pH all elicited harmful effects and limited the self-healing ability of sweet sorghum seedlings. In all, in order to grow sweet sorghum in the saline-alkaline soils of the Yellow River Delta, the salt concentration and pH value of the soil must be taken into consideration, and seeding density should be increased and supported by appropriate irrigation measures

  19. Towards improved quantification of post-fire conifer mortality and recovery: Impacts of fire radiative flux on seedling and mature tree mortality, physiology, and growth

    Science.gov (United States)

    Sparks, A. M.; Kolden, C.; Smith, A. M.

    2016-12-01

    Fire activity, in terms of intensity, frequency, and total area burned, is expected to increase with changing climate. A challenge for landscape level assessment of fire effects, termed burn severity, is that current assessments provide very little information regarding vegetation physiological performance and recovery, limiting our understanding of fire effects on ecosystem services such as carbon storage/cycling. To address these limitations, we evaluated an alternative dose-response methodology for quantifying fire effects that attempts to bridge fire combustion dynamics and ecophysiology. Specifically, we conducted a highly controlled, laboratory assessment of seedling response to increasing doses of fire radiative energy applied through surface fires, for two western U.S. conifer species. Seedling physiology and spectral reflectance were acquired pre- and up to 1 year post-fire. Post-fire mortality, physiological performance, and spectral reflectance were strongly related with fire radiative energy density (FRED: J m-2) dose. To examine how these relationships change with tree size and age, we conducted small prescribed fires at the tree scale (35 m2) in a mature conifer stand. Radial growth and resin duct defenses were assessed on the mature conifer trees following the prescribed fires. Differences in dose-response relationships between seedlings and mature trees indicate the importance of fire behavior (e.g., flaming-dominated versus smoldering-dominated combustion) in characterizing these relationships. Ultimately, these results suggest that post-fire impacts on growth of surviving seedlings and mature trees require modes of heat transfer to impact tree canopies.

  20. Lianas always outperform tree seedlings regardless of soil nutrients: results from a long-term fertilization experiment.

    Science.gov (United States)

    Pasquini, Sarah C; Wright, S Joseph; Santiago, Louis S

    2015-07-01

    Lianas are a prominent growth form in tropical forests, and there is compelling evidence that they are increasing in abundance throughout the Neotropics. While recent evidence shows that soil resources limit tree growth even in deep shade, the degree to which soil resources limit lianas in forest understories, where they coexist with trees for decades, remains unknown. Regardless, the physiological underpinnings of soil resource limitation in deeply shaded tropical habitats remain largely unexplored for either trees or lianas. Theory predicts that lianas should be more limited by soil resources than trees because they occupy the quick-return end of the "leaf economic spectrum," characterized by high rates of photosynthesis, high specific leaf area, short leaf life span, affinity to high-nutrient sites, and greater foliar nutrient concentrations. To address these issues, we asked whether soil resources (nitrogen, phosphorus, and potassium), alone or in combination, applied experimentally for more than a decade would cause significant changes in the morphology or physiology of tree and liana seedlings in a lowland tropical forest. We found evidence for the first time that phosphorus limits the photosynthetic performance of both trees and lianas in deeply shaded understory habitats. More importantly, lianas always showed significantly greater photosynthetic capacity, quenching, and saturating light levels compared to trees across all treatments. We found little evidence for nutrient x growth form interactions, indicating that lianas were not disproportionately favored in nutrient-rich habitats. Tree and liana seedlings differed markedly for six key morphological traits, demonstrating that architectural differences occurred very early in ontogeny prior to lianas finding a trellis (all seedlings were self-supporting). Overall, our results do not support nutrient loading as a mechanism of increasing liana abundance in the Neotropics. Rather, our finding that lianas

  1. Mycorrhizal inoculation of pecan seedlings with some marketable truffles

    Directory of Open Access Journals (Sweden)

    Gian M. Benucci

    2013-12-01

    Full Text Available Pecan is the common name of Carya illinoinensis (Wangenh. K. Koch, an ectomycorrhizal tree native to North America, also frequently known as hickory. Mycorrhizal inoculations of pecan seedlings with: Tuber aestivum Vittad., T. borchii Vittad., T. indicum Cooke & Massee, and T. lyonii Butters are described and discussed.

  2. Sewage sludge as substrate for Tectona grandis L. seedlings production

    Directory of Open Access Journals (Sweden)

    Daniele Rodrigues Gomes

    2013-03-01

    Full Text Available The sewage sludge is a waste from sewage treatment plants, which can be used in formulations of substrates for seedling production. This study aimed to evaluate the effects of different proportions of sewage sludge, soil and commercial substrate on the growth characteristics of Tectona grandis seedlings in tubes of 120 cm³ volume capacity. The sewage sludge used came from the STP's Cachoeiro de Itapemirim / ES. The seedlings were grown in the forest nursery / CCA / UFES. The statistical design used in the experiment was completely randomized design (CRD with six treatments and five replications. The treatments constituted of sewage sludge : commercial substrate: soil (v: v: v, which corresponded to 20:70:10 (T1, 40:50:10 (T2, 60:30:10 (T3, 80 : 10:10 (T4, 90:0:10 (T5 and the control treatment with 0:90:10 (T6. All variables assessed were significant at the 5% level of probability. The control (T6 showed results statistically equal to or lower than the treatments T3 with 60% of sewage sludge concentration (T3. It follows then that the use of sewage sludge in seedling production is feasible and promising, however, used in a proper proportion.

  3. [Characterization of growth-promoting rhizobacteria in Eucalyptus nitens seedlings].

    Science.gov (United States)

    Angulo, Violeta C; Sanfuentes, Eugenio A; Rodríguez, Francisco; Sossa, Katherine E

    2014-01-01

    Rhizospheric and endophytic bacteria were isolated from the rizosphere and root tissue of Eucalyptus nitens. The objective of this work was to evaluate their capacity to promote growth in seedlings of the same species under greenhouse conditions. The isolates that improved seedling growth were identified and characterized by their capacity to produce indoleacetic acid (IAA), solubilize phosphates and increase 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity. One hundred and five morphologically different strains were isolated, 15 of which promoted E. nitens seedling growth, significantly increasing the height (50%), root length (45%) as well as the aerial and root dry weight (142% and 135% respectively) of the plants. Bacteria belonged to the genus Arthrobacter, Lysinibacillus, Rahnella and Bacillus. Isolates A. phenanthrenivorans 21 and B. cereus 113 improved 3.15 times the emergence of E. nitens after 12 days, compared to control samples. Among isolated R. aquatilis, 78 showed the highest production of IAA (97.5±2.87 μg/ml) in the presence of tryptophan and the highest solubilizer index (2.4) for phosphorus, while B. amyloliquefaciens 60 isolate was positive for ACC deaminase activity. Our results reveal the potential of the studied rhizobacteria as promoters of emergence and seedling growth of E. nitens, and their possible use as PGPR inoculants, since they have more than one mechanism associated with plant growth promotion.

  4. Starch bioengineering affects cereal grain germination and seedling establishment

    DEFF Research Database (Denmark)

    Shaik, Shahnoor Sultana; Carciofi, Massimiliano; Martens, Helle Juel

    2014-01-01

    Cereal grain germination is central for plant early development, and efficient germination has a major role in crop propagation and malting. Endosperm starch is the prime energy reserve in germination and seedling establishment. In this study, it was hypothesized that optimized starch granule...

  5. Measuring Tree Seedlings and Associated Understory Vegetation in Pennsylvania's Forests

    Science.gov (United States)

    William H. McWilliams; Todd W. Bowersox; Patrick H. Brose; Daniel A. Devlin; James C. Finley; Kurt W. Gottschalk; Steve Horsley; Susan L. King; Brian M. LaPoint; Tonya W. Lister; Larry H. McCormick; Gary W. Miller; Charles T. Scott; Harry Steele; Kim C. Steiner; Susan L. Stout; James A. Westfall; Robert L. White

    2005-01-01

    The Northeastern Research Station's Forest Inventory and Analysis (NE-FIA) unit is conducting the Pennsylvania Regeneration Study (PRS) to evaluate composition and abundance of tree seedlings and associated vegetation. Sampling methods for the PRS were tested and developed in a pilot study to determine the appropriate number of 2-m microplots needed to capture...

  6. MARVIN : high speed 3D imaging for seedling classification

    NARCIS (Netherlands)

    Koenderink, N.J.J.P.; Wigham, M.L.I.; Golbach, F.B.T.F.; Otten, G.W.; Gerlich, R.J.H.; Zedde, van de H.J.

    2009-01-01

    The next generation of automated sorting machines for seedlings demands 3D models of the plants to be made at high speed and with high accuracy. In our system the 3D plant model is created based on the information of 24 RGB cameras. Our contribution is an image acquisition technique based on

  7. Phosphine-induced physiological and biochemical responses in rice seedlings.

    Science.gov (United States)

    Mi, Lina; Niu, Xiaojun; Lu, Meiqing; Ma, Jinling; Wu, Jiandong; Zhou, Xingqiu

    2014-04-01

    Paddy fields have been demonstrated to be one of the major resources of atmospheric phosphine and may have both positive and negative effects on rice plants. To elucidate the physiological and biochemical responses of rice plants to phosphine, rice seedlings (30 d old) were selected as a model plant and were treated with different concentrations of phosphine (0, 1.4, 4.2, and 7.0 mg m(-3)). Antioxidant enzymes, including superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), and lipid peroxidation measured via malondialdehyde (MDA) were determined as indicators of the physiological and biochemical responses of the rice seedlings to phosphine exposure. Increasing concentrations of phosphine treatment enhanced the activity of SOD, POD, and CAT. In addition, the MDA content increased with increasing concentrations of phosphine. These results suggested that antioxidant enzymes played important roles in protecting rice seedlings from ROS damage. Moreover, rice seedlings were able to cope with the oxidative stress induced by low concentrations of phosphine via an increase in antioxidant enzymatic activities. However, oxidative stress may not fully be prevented when the plants were exposed to higher concentrations of phosphine.

  8. The effect of ectomycorrhizal fungi and bacteria on pine seedlings

    Directory of Open Access Journals (Sweden)

    Hanna Dahm

    2014-08-01

    Full Text Available The effect of ecomycorrhizal fungi (Hebelon crustuliniforme(Bull.: Fr. Quél. 5392 and Pisolithus tinctorius (Pers. Coker et Couch 5335 and bacteria (Bacillus polymyxa and Azospirillum brasilense. associated with mycorrhizas on the growth of pine seedligs was investigated. In addition the influence of bacteria on fungal biomass production and the relationship between ectomycorrhizal fungi and fungi pathogenic to root of pine seedlings were determined. In general, the shoot/root ratio was higher in plants inoculated with Hebeloma crustuliniforme and bacteria than in the control seedlings (grown only under sterile conditions. In non-sterile substrate the root/shoot ratio of the mycorrhizal seedlings was lower as compared to the control. Similar phenomenon was noted in plants inoculated with the mycorrhizal fungus Pisolithus tinetorius. The bacteria used as well as the time of introduction of these organisms into the cultures of mycorrhiza fungi affected the production of fungal biomass. Hebeloma crustuliniforme and Pisolithus tinctorius inhibited the growth of Rizoctonia solani and Fusarium oxysporum fungi pathogenic to pine seedlings.

  9. Photosynthetic efficiency of Pedunculate oak seedlings under simulated water stress

    Directory of Open Access Journals (Sweden)

    Popović Zorica

    2010-01-01

    Full Text Available Photosynthetic performance of seedlings of Quercus robur exposed to short-term water stress in the laboratory conditions was assessed through the method of induced fluorometry. The substrate for seedlings was clayey loam, with the dominant texture fraction made of silt, followed by clay and fine sand, with total porosity 68.2%. Seedlings were separated in two groups: control (C (soil water regime in pots was maintained at the level of field water capacity and treated (water-stressed, WS (soil water regime was maintained in the range of wilting point and lentocapillary capacity. The photosynthetic efficiency was 0.642±0.25 and 0.522±0.024 (WS and C, respectively, which was mostly due to transplantation disturbances and sporadic leaf chlorosis. During the experiment Fv/Fm decreased in both groups (0.551±0.0100 and 0.427±0.018 in C and WS, respectively. Our results showed significant differences between stressed and control group, in regard to both observed parameters (Fv/Fm and T½. Photosynthetic efficiency of pedunculate oak seedlings was significantly affected by short-term water stress, but to a lesser extent than by sufficient watering.

  10. Soybean seedlings tolerate abrasion from air-propelled grit

    Science.gov (United States)

    New tools for controlling weeds would be useful for soybean production in organic systems. Air-propelled abrasive grit is one such tool that performs well for in-row weed control in corn, but crop safety in soybean is unknown. We examined responses to abrasion by corn-cob grit of soybean seedlings a...

  11. Optimal light for greenhouse culture of American ginseng seedlings

    Directory of Open Access Journals (Sweden)

    John T.A. Proctor

    2017-07-01

    Full Text Available Three greenhouse experiments with American ginseng seedlings growing under light levels from 4.8% to 68% showed a quadratic response for root dry weight, giving an optimal root dry weight of 239 mg (range 160–415 mg at an optimal light level of 35.6% (range 30.6–43.2%.

  12. Sugar signalling during germination and early seedling establishment in Arabidopsis

    NARCIS (Netherlands)

    Dekkers, S.J.W.

    2006-01-01

    Sugars have pronounced effects on many plant processes like gene expression, germination and early seedling development. Several screens for sugar insensitive mutants were performed to identify genes involved in sugar response pathways using the model plant Arabidopsis. These include sun, gin and si

  13. Identification of seedling cabbages and weeds using hyperspectral imaging

    Science.gov (United States)

    Target detectionis one of research focues for precision chemical application. This study developed a method to identify seedling cabbages and weeds using hyperspectral spectral imaging. In processing the image data, with ENVI software, after dimension reduction, noise reduction, de-correlation for h...

  14. Growth and Mineral Composition of Passion Fruit Seedlings

    Directory of Open Access Journals (Sweden)

    Edson Batista Lopes

    2010-06-01

    Full Text Available The aim of this study was to evaluate the growth and mineral composition of the yellow passion fruit plant seedlings (Passiflora edulis Sims f. flavicarpa Degener in fertilized substrates with boron and kalium, with and without coconut fiber (25 % e 0% and bovine manure (15%. The treatments were distributed in a outlined random block with four blocks and four seedlings per portion being five kalium doses and five boron doses combined according to the main Composite Central of Box. Each 20 days were done evaluations. Were analyzed the dry and green matter of the root and the leaf, foliated area and nutriment contents of the leaf. The results were submitted to analysis of change and regression. There was no significant effect of the treatments on the seedling's height, diameter of the shaft, number of leaves and foliated area. The coconut fiber doesn’t affect their growth and mineral composition. The kalium increased in a lineal way the root growth and aerial part of the seedlings, either the foliar contents of kalium, but reduce magnesium proportions. The boron increased the foliar contents of boron and reduced the nitrogen’s.

  15. Proteome Profiling of Paulownia Seedlings Infected with Phytoplasma

    Science.gov (United States)

    Cao, Xibing; Fan, Guoqiang; Dong, Yanpeng; Zhao, Zhenli; Deng, Minjie; Wang, Zhe; Liu, Wenshan

    2017-01-01

    Phytoplasma is an insect-transmitted pathogen that causes witches' broom disease in many plants. Paulownia witches' broom is one of the most destructive diseases threatening Paulownia production. The molecular mechanisms associated with this disease have been investigated by transcriptome sequencing, but changes in protein abundance have not been investigated with isobaric tags for relative and absolute quantitation. Previous results have shown that methyl methane sulfonate (MMS) can help Paulownia seedlings recover from the symptoms of witches' broom and reinstate a healthy morphology. In this study, a transcriptomic-assisted proteomic technique was used to analyze the protein changes in phytoplasma-infected Paulownia tomentosa seedlings, phytoplasma-infected seedlings treated with 20 and 60 mg·L−1 MMS, and healthy seedlings. A total of 2,051 proteins were obtained, 879 of which were found to be differentially abundant in pairwise comparisons between the sample groups. Among the differentially abundant proteins, 43 were related to Paulownia witches' broom disease and many of them were annotated to be involved in photosynthesis, expression of dwarf symptom, energy production, and cell signal pathways. PMID:28344590

  16. Inhibitory effects of monoterpenes on seed germination and seedling growth.

    Science.gov (United States)

    Kordali, Saban; Cakir, Ahmet; Sutay, Sunay

    2007-01-01

    Monoterpenes, the chemical constituents of essential oils found in plants, are known biologically active compounds. The present study was conducted to investigate the inhibitory effects of 30 monoterpenes including monoterpene hydrocarbons and oxygenated monoterpenes on seed germination and seedling growth of Amaranthus retroflexus, Chenopodium album and Rumex crispus under laboratory conditions. The monoterpenes were applied at contents of 10 and 20 microl for liquid compounds and 10 and 20 microg for solid compounds. The results show that most of the monoterpenes significantly inhibited seed germination and seedling growth of the tested plants. Oxygenated monoterpenes including beta-citronellol, nerol and terpinen-4-ol completely inhibited seed germination and seedling growth of all tested plants. Their inhibitory effects were also stronger than that of the herbicide 2,4-D. In general, monoterpenes were less effective against seed germination and seedling growth of C. album as compared with R. crispus and A. retroflexus. Phytotoxic effects of monoterpene hydrocarbons were found to be lower than those of oxygenated monoterpenes. The alcohol derivatives of oxygenated monoterpenes were also found to be more phytotoxic as compared with their acetate derivatives. Based on the present results, it can be concluded that the oxygenated monoterpenes can be used as potential bio-herbicides.

  17. No de novo sulforaphane biosynthesis in broccoli seedlings

    NARCIS (Netherlands)

    Gorissen, Antonie; Kraut, Nicolai U.; de Visser, Ries; de Vries, Marcel; Roelofsen, Han; Vonk, Roel J.

    2011-01-01

    The isothiocyanate sulforaphane, present in significant amounts in broccoli (Brassica oleracea L.) seedlings in the form of its precursor glucoraphanin, has been identified as an inducer of quinine reductase, a phase-II detoxification enzyme known for its anticarcinogenic properties. Its

  18. Growth promotion mediated by endophytic fungi in cloned seedlings ...

    African Journals Online (AJOL)

    Elohor Owebor

    2016-11-30

    Nov 30, 2016 ... promote plant growth and productivity (Chang et al., .... software Sigma Scan Pro- V.S. O, Jandel Scientific. The quarterly values for stem length and stem diameter were used to determine the percentage growth increase of the seedlings ... values were obtained after six days of drying in a forced air oven at.

  19. Phototropism in seedlings of sunflower, Helianthus annuus L.

    NARCIS (Netherlands)

    Franssen, J.M.

    1980-01-01

    In this thesis the phototropic bending of hypocotyls of sunflower seedlings, Helianthus annuus L., is investigated.

    Chapter 1 gives the reasons for this project. Although phototropism has been studied extensively over the past 100 years, the understanding of

  20. Response of Raphia (Raphia Hookeri) Palm Seedlings to Fertilizer ...

    African Journals Online (AJOL)

    2012r

    2014-11-17

    Nov 17, 2014 ... Key words: Nursery, fertilizer application, Raphia hookeri seedling, dry ... holder farms is the fundamental root causes of declining per capital food ... requirements of plants and the nutrient reserves in the soils is essential for ... A good fertilizer management programme is important to achieve good soil.

  1. Effect of trace elements on growth of Pinus tabulaeformis seedling

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The stimulative effect of trace elements on seed germination and seedling growth of Pinus tabulaeformis was tested. The experiments were carried out on seed soak and topdressing with different trace elements and varied concentrat ions at the nursery of Gardens Research Institute, Harbin, in 2000-2001. The experimental results showed that soaking seed with 1% and 0.2% concentrations of Mn element produced best result for seed germination, and the germination rate was increased by 9%~19% for the seeds treated with 1% concentration and 12%~14% for the seeds treated with 0.2% concentration compared with the control group. The seeds treated with boron element had lowest germination rate. For trace element topdressing, Mn and Mo elements presented good result for seedling growth and th e treatment with low concentration was even better. The height or chlorophyll co ntent of the seedlings with spray of low-concentration Mn and Mo element was muc h higher than that of untreated ones. In the contrast to the treating method of seed soak, topdressing (application of spraying on foliage) had evident effect o n seedling growth.

  2. Sesinoside, a new iridoid glucoside from sesame (Sesamum indicum) seedlings.

    Science.gov (United States)

    Takase, Ryo; Hasegawa, Tsuyoshi; Yamada, Kosumi; Hasegawa, Koji; Shigemori, Hideyuki

    2014-11-01

    A new iridoid glucoside, sesinoside (1), was isolated from the seedlings of Sesamum indicum. The structure of 1 was elucidated by spectroscopic analyses and by methanolysis of 1, which produced the known compounds, phlorigidosides C (2) and (6Z)-foliamenthic acid methyl ester (3). This is the first report of an iridoid glucoside with 3.

  3. Flood tolerance of oak seedlings from bottomland and upland sites

    Science.gov (United States)

    Michael P. Walsh; Jerry Van Sambeek; Mark Coggeshall; David. Gwaze

    2009-01-01

    Artificial regeneration of oak species in floodplains presents numerous challenges because of the seasonal flooding associated with these areas. Utilizing not only flood-tolerant oak species, but also flood tolerant seed sources of the oak species, may serve to enhance seedling survival and growth rates. Despite the importance of these factors to hardwood forest...

  4. Phototropism in seedlings of sunflower, Helianthus annuus L

    NARCIS (Netherlands)

    Franssen, J.M.

    1980-01-01

    In this thesis the phototropic bending of hypocotyls of sunflower seedlings, Helianthus annuus L., is investigated.Chapter 1 gives the reasons for this project. Although phototropism has been studied extensively over the past 100 years, the understanding of the mechanism is far from clear. During th

  5. Inverse Limits

    CERN Document Server

    Ingram, WT

    2012-01-01

    Inverse limits provide a powerful tool for constructing complicated spaces from simple ones. They also turn the study of a dynamical system consisting of a space and a self-map into a study of a (likely more complicated) space and a self-homeomorphism. In four chapters along with an appendix containing background material the authors develop the theory of inverse limits. The book begins with an introduction through inverse limits on [0,1] before moving to a general treatment of the subject. Special topics in continuum theory complete the book. Although it is not a book on dynamics, the influen

  6. Drought survival of tropical tree seedlings enhanced by non-structural carbohydrate levels

    Science.gov (United States)

    O'Brien, Michael J.; Leuzinger, Sebastian; Philipson, Christopher D.; Tay, John; Hector, Andy

    2014-08-01

    Plants in most biomes are thought to be living at their hydraulic limits, and alterations to precipitation patterns consistent with climate change trends are causing die-back in forests across the globe. However, within- and among-species variation in plant traits that promote persistence and adaptation under these new rainfall regimes may reduce mortality in these changing climates. Storage of non-structural carbohydrates (NSCs) is posited as an important trait for resistance and resilience of forests to climate-change-induced drought, but the underlying mechanisms remain unclear. Here we demonstrate a positive relationship between NSCs and drought survival by manipulating NSC concentrations within seedlings of ten tropical tree species. Seedlings experimentally enriched in NSCs showed higher stem water potentials and sustained NSCs during drought. NSC use for maintenance of osmoregulation and hydraulic function therefore seems to underlie improved drought resistance. That drought mortality is delayed by higher NSC concentrations has implications for predicting the impacts of climate change on forest die-back and may help focus restoration efforts on species that increase the resistance and resilience of forests to climate change.

  7. [Effects of exogenous spermidine on Cucumis sativus L. seedlings photosynthesis under root zone hypoxia stress].

    Science.gov (United States)

    Wang, Tian; Wang, Suping; Guo, Shirong; Sun, Yanjun

    2006-09-01

    With water culture, this paper studied the effects of exogenous spermidine (Spd) on the net photosynthetic rate (Pn), intercellular CO2 concentrations (Ci), stomatal conductance (Gs), transpiration rate (Tr), apparent quantum yield (phi c), and carboxylation efficiency (CE) of cucumber seedlings tinder hypoxia stress. The results showed that the Pn decreased gradually under hypoxia stress, and reached the minimum 10 days after by 63. 33% of the control. Compared with that of hypoxia-stressed plants, the Pn after 10 days application of exogenous Spd increased 1.25 times. A negative correlation (R2 = 0.4730 - 0.7118) was found between Pn and Ci. Gs and Tr changed in wider ranges, which decreased under hypoxia-stress, but increased under hypoxia-stress plus exogenous Spd application. There was a significant positive correlation between Gs and Tr (R2 = 0.7821 - 0.9458), but these two parameters had no significant correlation with Pn; Hypoxia stress induced a decrease of phi c and CE by 63.01% and 72.33%, respectively, while hypoxia stress plus exogenous Spd application made phi c and CE increase by 23% and 14%, respectively. The photo-inhibition of cucumber seedlings under hypoxia stress was mainly caused by non-stomatal limitation, while exogenous Spd alleviated the hypoxia stress by repairing photosynthesis system.

  8. Transcriptome Profiling of Wheat Seedlings following Treatment with Ultrahigh Diluted Arsenic Trioxide

    Directory of Open Access Journals (Sweden)

    Ilaria Marotti

    2014-01-01

    Full Text Available Plant systems are useful research tools to address basic questions in homeopathy as they make it possible to overcome some of the drawbacks encountered in clinical trials (placebo effect, ethical issues, duration of the experiment, and high costs. The objective of the present study was to test the hypothesis whether 7-day-old wheat seedlings, grown from seeds either poisoned with a sublethal dose of As2O3 or unpoisoned, showed different significant gene expression profiles after the application of ultrahigh diluted As2O3 (beyond Avogadro’s limit compared to water (control. The results provided evidence for a strong gene modulating effect of ultrahigh diluted As2O3 in seedlings grown from poisoned seeds: a massive reduction of gene expression levels to values comparable to those of the control group was observed for several functional classes of genes. A plausible hypothesis is that ultrahigh diluted As2O3 treatment induced a reequilibration of those genes that were upregulated during the oxidative stress by bringing the expression levels closer to the basal levels normally occurring in the control plants.

  9. Variation in Ecophysiological Traits and Drought Tolerance of Beech (Fagus sylvatica L.) Seedlings from Different Populations

    Science.gov (United States)

    Cocozza, Claudia; de Miguel, Marina; Pšidová, Eva; Ditmarová, L'ubica; Marino, Stefano; Maiuro, Lucia; Alvino, Arturo; Czajkowski, Tomasz; Bolte, Andreas; Tognetti, Roberto

    2016-01-01

    Frequency and intensity of heat waves and drought events are expected to increase in Europe due to climate change. European beech (Fagus sylvatica L.) is one of the most important native tree species in Europe. Beech populations originating throughout its native range were selected for common-garden experiments with the aim to determine whether there are functional variations in drought stress responses among different populations. One-year old seedlings from four to seven beech populations were grown and drought-treated in a greenhouse, replicating the experiment at two contrasting sites, in Italy (Mediterranean mountains) and Germany (Central Europe). Experimental findings indicated that: (1) drought (water stress) mainly affected gas exchange describing a critical threshold of drought response between 30 and 26% SWA for photosynthetic rate and Ci/Ca, respectively; (2) the Ci to Ca ratio increased substantially with severe water stress suggesting a stable instantaneous water use efficiency and an efficient regulation capacity of water balance achieved by a tight stomatal control; (3) there was a different response to water stress among the considered beech populations, differently combining traits, although there was not a well-defined variability in drought tolerance. A combined analysis of functional and structural traits for detecting stress signals in beech seedlings is suggested to assess plant performance under limiting moisture conditions and, consequently, to estimate evolutionary potential of beech under a changing environmental scenario. PMID:27446118

  10. Establishing northern red oak on a degraded upland site in northeastern Pennsylvania: Influence of seedling pedigree and quality

    Science.gov (United States)

    Cornelia C. Pinchot; Thomas J. Hall; Scott E. Schlarbaum; Arnold M. Saxton; James. Bailey

    2017-01-01

    Enrichment plantings using large oak seedlings of regional sources may promote superior survival and growth compared to direct seeding or standard nursery seedling material. This study evaluated the survival and growth of planted 1-0 northern red oak (Quercus rubra L.) seedlings among 11 families and 3 seedling size classes (small, average, and...

  11. Neighborhood and community interactions determine the spatial pattern of tropical tree seedling survival.

    Science.gov (United States)

    Queenborough, Simon A; Burslem, David F R P; Garwood, Nancy C; Valencia, Renato

    2007-09-01

    Factors affecting survival and recruitment of 3531 individually mapped seedlings of Myristicaceae were examined over three years in a highly diverse neotropical rain forest, at spatial scales of 1-9 m and 25 ha. We found convincing evidence of a community compensatory trend (CCT) in seedling survival (i.e., more abundant species had higher seedling mortality at the 25-ha scale), which suggests that density-dependent mortality may contribute to the spatial dynamics of seedling recruitment. Unlike previous studies, we demonstrate that the CCT was not caused by differences in microhabitat preferences or life history strategy among the study species. In local neighborhood analyses, the spatial autocorrelation of seedling survival was important at small spatial scales (1-5 m) but decayed rapidly with increasing distance. Relative seedling height had the greatest effect on seedling survival. Conspecific seedling density had a more negative effect on survival than heterospecific seedling density and was stronger and extended farther in rare species than in common species. Taken together, the CCT and neighborhood analyses suggest that seedling mortality is coupled more strongly to the landscape-scale abundance of conspecific large trees in common species and the local density of conspecific seedlings in rare species. We conclude that negative density dependence could promote species coexistence in this rain forest community but that the scale dependence of interactions differs between rare and common species.

  12. First year survival of barefoot and containerized hardwood tree seedlings planted in northeast Texas lignite minesoils

    Energy Technology Data Exchange (ETDEWEB)

    Wood, J.; Denman, J. [Texas Utilities Mining Company, Mt. Pleasant, TX (United States); Waxler, M.; Huber, D.A. [Weyerhaeuser, Hot Springs, AK (United States)

    1997-12-31

    Successful regeneration of hardwood tree seedlings is critical to the reclamation of quality wildlife habitat and commercial forests on lignite mines in northeast Texas. Because bareroot hardwood seedlings survival rates have often been lower than desired, the survival of containerized and bareroot hardwood tree seedlings was compared. Seven hardwood species, including six species of oaks, were planted in lignite minesoils on sites classified as bottomland, slope and upland. Three species were planted per site. Containerized seedlings were planted during the fall and winter, whereas bareroot seedlings were planted in the winter only. Survival was determined at the end of the first growing season. Results across all sites indicate that winter-planted containerized seedlings (74%) or bareroot seedlings (76%). Within the sites, the only significant difference was on upland sites where survival of winter-planted containerized seedlings (60%) was lower than bareroot seedlings (77%). Survival among species was not significantly different. There was no significant survival benefit from using more expensive containerized hardwood seedlings. The results also question the practice of planting containerized hardwood seedlings during the typical winter planting season for optimum survival.

  13. Biological seed priming mitigates the effects of water stress in sunflower seedlings.

    Science.gov (United States)

    Singh, Narsingh Bahadur; Singh, Deepmala; Singh, Amit

    2015-04-01

    The sunflower (Helianthus annuus L. cv. PAC 36) seedlings were inoculated with plant growth promoting rhizobacteria (PGPR), viz. Azotobacter chroococcum (A+), Bacillus polymyxa (B+), separately and in combination of the two (AB+). Relative water content and seedling growth were maximum in AB+ seedlings under control. Water stress significantly decreased the RWC, growth and dry mass of non-inoculated seedlings. However, inoculated seedlings maintained higher growth even under water stress. Pigments and protein contents decreased under water stress, but higher amount of the same was observed in stressed AB+ seedlings. Enhanced activity of nitrate reductase was recorded in AB+ seedlings with maximum in control. Water stress significantly decreased the nitrate reductase activity. A significant increase in the activity of superoxide dismutase (SOD) in leaves was recorded under water stress except in B+ with maximum increase in non-inoculated seedlings. Catalase (CAT) activity decreased in stressed non-inoculated seedlings while increased in the leaves of A+ and AB+ seedlings. Almost similar trends were recorded for both leaves and cotyledons. PGPR improved the water status in stressed seedlings and thereby physiological and biochemical parameters and thus ameliorated the severe effects of water stress.

  14. Effects of seed traits variation on seedling performance of the invasive weed, Ambrosia artemisiifolia L.

    Science.gov (United States)

    Ortmans, William; Mahy, Grégory; Monty, Arnaud

    2016-02-01

    Seedling performance can determine the survival of a juvenile plant and impact adult plant performance. Understanding the factors that may impact seedling performance is thus critical, especially for annuals, opportunists or invasive plant species. Seedling performance can vary among mothers or populations in response to environmental conditions or under the influence of seed traits. However, very few studies have investigated seed traits variations and their consequences on seedling performance. Specifically, the following questions have been addressed by this work: 1) How the seed traits of the invasive Ambrosia artemisiifolia L. vary among mothers and populations, as well as along the latitude; 2) How do seed traits influence seedling performance; 3) Is the influence on seedlings temperature dependent. With seeds from nine Western Europe ruderal populations, seed traits that can influence seedling development were measured. The seeds were sown into growth chambers with warmer or colder temperature treatments. During seedling growth, performance-related traits were measured. A high variability in seed traits was highlighted. Variation was determined by the mother identity and population, but not latitude. Together, the temperature, population and the identity of the mother had an effect on seedling performance. Seed traits had a relative impact on seedling performance, but this did not appear to be temperature dependent. Seedling performance exhibited a strong plastic response to the temperature, was shaped by the identity of the mother and the population, and was influenced by a number of seed traits.

  15. Influence of ozone on cold acclimation in sugar maple seedlings

    Energy Technology Data Exchange (ETDEWEB)

    Bertrand, A. [Agriculture and Agri-Food Canada, Sainte-Foy, PQ (Canada) Research Station; Robitaille, G. [Natural Resources Canada, Ste. Foy, PQ (Canada) Canadian Forest Service; Nadeau, P.; Castonguay, Y. [Agriculture and Agri-Food Canada, Sainte-Foy, PQ (Canada) Research Station

    1999-07-01

    A study was carried out with the aim of determining: a) if exposure to ozone gas induces changes in the key parts of cold acclimation in maple seedlings; and b) if the putative changes effect the process of cold acclimation. Two year old seedlings were exposed to two concentrations of ozone, ambient ozone (low ozone), and threefold ambient ozone concentrations (high ozone) from June to September. During the fall, winter and spring, the seedlings were left outdoors to acclimate to natural winter conditions. The freezing tolerance of stems and root tissues was determined for high ozone and low ozone treated seedlings over the winter period. Concomitant determination of the concentrations of starch, sucrose, raffinose, and stachyose in the sugar maple roots as well as ABA concentration in the xylem sap were carried out to assess the molecular changes associated with the cold acclimation of seedlings in the two treatments. Exposure to high concentrations of ozone did not decrease the freezing tolerance of sugar maple roots and improved the freezing tolerance of the stems in the fall. During the period of cold acclimation, an eightfold increase in sucrose concentration occurred in roots and stems, while starch concentration decreased. In roots, the accumulation of soluble sugars coincided with the period of lowest soil temperature. This showed that temperature has a major influence on the amount of sugar formed and the degree of freezing tolerance. There were no ozone treatment effects on either starch hydrolysis or sucrose accumulation in roots. Sucrose is a membrane and protein stabilizer during winter drying. In roots, the concentrations of the galactose containing oligosaccharides, raffinose and stachyose, were higher in the high ozone treatment than in the low ozone treatment, and stachyose indicated a similar response in stems. There is a relation between the increase in ABA concentration and cold acclimation in the sugar maple. 29 refs., 7 figs.

  16. Effects of vesicular-arbuscular mycorrhizal (VAM) fungi on the seedling growth of three Pistacia species.

    Science.gov (United States)

    Caglar, S; Akgun, A

    2006-07-01

    The experiment was undertaken to test the efficiency of inoculation of vesicular-arbuscular mycorrhizal (VAM) fungi on the seedling growth of three Pistacia species used as rootstocks. The stratified Pistacia seeds were inoculated with VAM fungi. The highest rate of inoculated roots was 96.7% in P. khinjuck seedlings with G. clarum and G. etunicatum, 83.3% in P. vera seedlings with G. caledonium and 73.3% in P. terebinthus seedlings with G. caledonium. Mycorrhizal inoculations improved seedling height only in P. terebinthus. Certain mycorrhizal inoculations increased the leaf N, but not P and K contents. Seedlings inoculated with G. caledonium had higher reducing sugar contents. It was concluded that pre-inoculated Pistacia seedlings could have a better growth in the harsh field conditions.

  17. Changes in soluble carbohydrates and related enzymes induced by low temperature during early developmental stages of quinoa (Chenopodium quinoa) seedlings.

    Science.gov (United States)

    Rosa, Mariana; Hilal, Mirna; González, Juan A; Prado, Fernando E

    2004-06-01

    Low temperature represents one of the principal limitations in species distribution and crop productivity. Responses to chilling include the accumulation of simple carbohydrates and changes in enzymes involved in their metabolism. Soluble carbohydrate levels and invertase, sucrose synthase (SS), sucrose-6-phosphate synthase (SPS) and alpha-amylase activities were analysed in cotyledons and embryonic axes of quinoa seedlings grown at 5 degrees C and 25 degrees C in the dark. Significant differences in enzyme activities and carbohydrate levels were observed. Sucrose content in cotyledons was found to be similar in both treatments, while in embryonic axes there were differences. Invertase activity was the most sensitive to temperature in both organs; however, SS and SPS activities appear to be less stress-sensitive. Results suggest that 1) metabolism in germinating perispermic seeds would be different from endospermic seeds, 2) sucrose futile cycles would be operating in cotyledons, but not in embryonic axes of quinoa seedlings under our experimental conditions, 3) low temperature might induce different regulatory mechanisms on invertase, SS and SPS enzymes in both cotyledons and embryonic axes of quinoa seedlings, and 4) low temperature rather than water uptake would be mainly responsible for the changes observed in carbohydrate and related enzyme activities.

  18. Understanding Trichoderma in the root system of Pinus radiata: associations between rhizosphere colonisation and growth promotion for commercially grown seedlings.

    Science.gov (United States)

    Hohmann, Pierre; Jones, E Eirian; Hill, Robert A; Stewart, Alison

    2011-08-01

    Two Trichoderma isolates (T. hamatum LU592 and T. atroviride LU132) were tested for their ability to promote the growth and health of commercially grown Pinus radiata seedlings. The colonisation behaviour of the two isolates was investigated to relate rhizosphere competence and root penetration to subsequent effects on plant performance. Trichoderma hamatum LU592 was shown to enhance several plant health and growth parameters. The isolate significantly reduced seedling mortality by up to 29%, and promoted the growth of shoots (e.g. height by up to 16%) and roots (e.g. dry weight by up to 31%). The introduction of LU592 as either seed coat or spray application equally improved seedling health and growth demonstrating the suitability of both application methods for pine nursery situations. However, clear differences in rhizosphere colonisation and root penetration between the two application methods highlighted the need for more research on the impact of inoculum densities. When spray-applied, LU592 was found to be the predominant Trichoderma strain in the plant root system, including bulk potting mix, rhizosphere and endorhizosphere. In contrast, T. atroviride LU132 was shown to colonise the root system poorly, and no biological impact on P. radiata seedlings was detected. This is the first report to demonstrate rhizosphere competence as a useful indicator for determining Trichoderma bio-inoculants for P. radiata. High indigenous Trichoderma populations with similar population dynamics to the introduced strains revealed the limitations of the dilution plating technique, but this constraint was alleviated to some extent by the use of techniques for morphological and molecular identification of the introduced isolates.

  19. [Effects of gap size on seedling natural regeneration in artificial Pinus tabulaeformis plantation].

    Science.gov (United States)

    Han, Wen-Juan; Yuan, Xiao-Qing; Zhang, Wen-Hui

    2012-11-01

    To clarify the effects of gap size created by thinning on the seedling natural regeneration in artificial Pinus tabulaeformis plantation, a plot investigation was conducted to study the ecological factors and the age structure, height, diameter, length of needles, and dry biomass of roots, stems, and needles of 1-10 year-old seedlings in different habitats, and a path analysis was made on the environmental factors affecting the seedling regeneration. Obvious differences were observed in the ecological factors in different size gaps and slope aspects. There lacked of above 3 year-old seedlings in understory and of above 7 year-old seedlings in small gap, and the seedlings of 5 and 6 year-old were lesser in big gap. The 1-10 year-old seedlings could be divided into 3 development phases, i. e. , 1-3 year-old, 4-7 year-old, and 8-10 year-old seedlings, among which, 1-3 year-old seedlings were critical for the establishment and growth of the population. The growth situation of the seedlings in different habitats was in order of big gap in shady slope > big gap in sunny slope > small gap in sunny slope > small gap in shady slope > understory in sunny slope > understory in shady slope. Path analysis showed light intensity had decisive positive effects on the seedling number of different development phases, shrub coverage had decisive negative effects on the seedling number of 4-7 year-old and 8-10 year-old phases, whereas humus dry mass had negative effects on the seedling number of 4-7 year-old but positive effects on the seedling number of 8-10 year-old. It was suggested that in the management of artificial P. tabulaeformis plantation, relatively high intensity thinning combined with shrub clearing should be adopted to provide favorable conditions for the sustainable development of P. tabulaeformis population.

  20. A rapid and robust method of identifying transformed Arabidopsis thaliana seedlings following floral dip transformation

    Directory of Open Access Journals (Sweden)

    Gray John C

    2006-11-01

    Full Text Available Abstract Background The floral dip method of transformation by immersion of inflorescences in a suspension of Agrobacterium is the method of choice for Arabidopsis transformation. The presence of a marker, usually antibiotic- or herbicide-resistance, allows identification of transformed seedlings from untransformed seedlings. Seedling selection is a lengthy process which does not always lead to easily identifiable transformants. Selection for kanamycin-, phosphinothricin- and hygromycin B-resistance commonly takes 7–10 d and high seedling density and fungal contamination may result in failure to recover transformants. Results A method for identifying transformed seedlings in as little as 3.25 d has been developed. Arabidopsis T1 seeds obtained after floral dip transformation are plated on 1% agar containing MS medium and kanamycin, phosphinothricin or hygromycin B, as appropriate. After a 2-d stratification period, seeds are subjected to a regime of 4–6 h light, 48 h dark and 24 h light (3.25 d. Kanamycin-resistant and phosphinothricin-resistant seedlings are easily distinguished from non-resistant seedlings by green expanded cotyledons whereas non-resistant seedlings have pale unexpanded cotyledons. Seedlings grown on hygromycin B differ from those grown on kanamycin and phosphinothricin as both resistant and non-resistant seedlings are green. However, hygromycin B-resistant seedlings are easily identified as they have long hypocotyls (0.8–1.0 cm whereas non-resistant seedlings have short hypocotyls (0.2–0.4 cm. Conclusion The method presented here is an improvement on current selection methods as it allows quicker identification of transformed seedlings: transformed seedlings are easily discernable from non-transformants in as little as 3.25 d in comparison to the 7–10 d required for selection using current protocols.

  1. Relationships between established seedling survival and growth in evergreen broad-leaved forest in Tiantong

    Directory of Open Access Journals (Sweden)

    Heming Liu

    2017-01-01

    Full Text Available Community seedling regeneration is a crucial process for maintaining species coexistence. The stage from which an established seedling becomes a new reproductive individual is one of the most important components of community regeneration, and influences the community recruitment pattern. However, the short-term mortality of established seedlings is lower than newly germinated seedlings, and previous studies have not been able to analyze the effect of biotic neighborhoods and abiotic micro-habitat factors on established seedling survival perfectly. Therefore, we suggest that the growth status of established seedlings could predict established seedling survival during development, and analyze the effects of these biotic and abiotic factors on established seedling growth, in order to indirectly estimate their effects on established seedling survival. To test this hypothesis, we selected established seedlings in the 20 ha forest dynamics plot in Tiantong as samples. Then, we used generalized linear mixed models to assess the effects of relative growth rate, biotic neighborhood factors (conspecific/heterospecific adult neighborhood indices, density of conspecific/heterospecific seedling neighbors, the amount of conspecific/heterospecific leaf litter from neighbors and abiotic micro-habitat factors (canopy openness, herbaceous coverage, elevation, slope, aspect, pH value, total nitrogen and total phosphorus in the soil on short-term established seedling survival rates. We used linear mixed models to assess the effects of biotic neighborhood factors and abiotic micro-habitat factors on relative growth rates of established seedlings. Results showed that relative growth rates have a significant, positive effect on established seedling survival, and this factor is the most important factor among potential influencing factors. In addition, canopy openness, as only one significant influencing factor, has a positive effect on relative growth rates of

  2. Effects of Light Intensity and Fertilization on the Growth of Andean Oak Seedlings at Nursery

    Directory of Open Access Journals (Sweden)

    Yira Lucia Sepúlveda

    2014-03-01

    Full Text Available Quercus humboldtii is a native plant species of great importance in Colombia for use in reforestation and restoration of degraded Andean highlands. The species is highly threatened and it is necessary to establish programs of propagation and planting. However, little is known about their nutritional and light requirements. The aim of this study was to determine the effects of single and combined relative illumination (IR and fertilization on the growth of seedlings of  Q. humboldtii at nursery. For this purpose three contrasting IR regimes (high, medium, and low IR and nine fertilization treatments were established: complete (TC, a missing nutrient (-N,-P,-K,-Ca,-Mg, -S,-B and a control without fertilization (T0. The best development of seedlings was showed in the medium IR condition. All treatments with a lacking nutrient showed decreases in seedling development regarding TC, except in the –B treatment. Nitrogen was the most limiting nutrient yielding biomass similar to that of T0. The impact of nutrient limitation on seedling performance was in the following order:-N>-Ca,-K,-P>-Mg,-S>-B. No significant interaction IR x Fertilization was detected on seedling development.EFECTOS DE LA ILUMINACIÓN RELATIVA Y LA FERTILIZACIÓN SOBRE EL CRECIMIENTO DE PLÁNTULAS DE ROBLE ANDINO EN VIVEROQuercus humboldtii es una especie vegetal nativa de mucha importancia en Colombia por su uso en repoblamiento forestal y restauración de tierras altoandinas degradadas. La especie se encuentra fuertemente amenazada y es necesario establecer programas de propagación de la misma. Sin embargo, poco se conoce sobre sus exigencias nutricionales y lumínicas. El objetivo de este estudio fue determinar los efectos simples y combinados de la iluminación relativa (IR y la fertilización sobre el crecimiento de plántulas de  Q. humboldtii en vivero. Para esto se establecieron en combinación tres condiciones contrastantes de iluminación relativa (alta, media y baja

  3. Effects of Cutting Density on Growth,Yield and Quality of Poplar Clone Seedlings

    Institute of Scientific and Technical Information of China (English)

    Fang Shengzuo; Tian Ye; Yuan Fayin

    2006-01-01

    In order to identify the optimum cutting density for producing the highest number of plantable seedlings of poplar clones,a split-plot randomized block design was used to establish four cutting densities in plots.Based on data on the survival,leaf area,seedling height,caliper,and biomass of 1-year-old seedlings of clones Nanlin-95,Nanlin-895,Nanlin-1388 and NL-80351,the growth characteristics and seedling quality under four cutting densities were analyzed.Results indicated that the leaf area,stern and leaf biomass,and caliper of seedlings of all four poplar clones increased with the decrease in cutting density.Leaf area index reached its highest level at the spacing of 40 cm×40 cm,while the aboveground biomass of the seedling on an area basis increased as the cutting density increased.Seedling quality at low cutting density was higher than that at closer cutting density.The quantity of first-grade seedlings (grade Ⅰ) for clones Nanlin-95 and Nanlin-895 was achieved at the spacing of 40 cm×50 cm;for NL-1388 and NL-80351,it was 50 cm×50 cm.According to the seedling quality and the number of plantable seedlings produced,the suggested cutting density for these four poplar clones was 50,000 stems/hm2.

  4. Higher Chilling-Tolerance of Grafted-Cucumber Seedling Leaves upon Exposure to Chilling Stress

    Institute of Scientific and Technical Information of China (English)

    LI Jian-yong; TIAN Hai-xia; LI Xin-guo; MENG Jing-jing; HE Qi-wei

    2008-01-01

    The roots of figleaf gourd (Cucurbita ficifolia, as rootstock) could improve the resistance of cucumber plants (Cucumis sativus L. cv. Jinyan 4, as scion) to low temperature. In this experiment, the root activity and photosynthetic activity of photosystems in the own-rooted and grafted-cucumber plants were studied at chilling temperature (4℃) under low irradiance (100 μmol m-2 s-1 PFD). Compared with dark adaptation seedlings, the chlorophyll a fluorescence transient curve and the oxidizable P700 (P700+) of both the own-rooted and grafted seedlings decreased, and PS2 and PSl of the own-rooted seedling leaves were more inhibited than that of grafted ones at the end of chilling stress. The reduced triphenyltetrazolium chloride (TTC), which was used to reflect the root activity, kept stable in grafted seedling roots at the end of chilling stress, while it decreased noticeably in the own-rooted seedling roots. These results implied that the root system activity of the grafted seedling roots was higher than that of the own-rooted ones. Superoxide dismutase (SOD) activity was higher in both the grafted seedling roots and leaves than that in own-rooted seedlings at both room temperature and chilling temperature. Upon exposure to chilling stress, the malondialdehyde (MDA) content, which reflects the degree of lipid peroxidation, increased markedly in the own-rooted seedling roots and leaves and kept stable in the grafted-cucumber seedlings.

  5. Implications of seed size for seedling survival in Carnegiea gigantea and Ferocactus wislizeni (Cactaceae)

    Science.gov (United States)

    Bowers, Janice E.; Pierson, E.A.

    2001-01-01

    Larger seeds have been shown to convey benefits for seedling survival but the mechanisms of this process are not well understood. In this study, seed size and seedling survival were compared for 2 sympatric cactus species, Carnegiea gigantea (Engelm.) Britt. & Rose and Ferocactus wislizeni (Engelm.) Britt. & Rose, in laboratory and field experiments in the northern Sonoran Desert. Both species have small seeds, but Ferocactus seeds are nearly twice as long and 3 times as heavy as those of Carnegiea. The difference in size is perpetuated after germination: new Ferocactus seedlings have 4 times the estimated volume of new Carnegiea seedlings. In an outdoor experiment, annual survivorship of both species was low but was 6 times higher for Ferocactus (6 seedlings, 8.1%) than Carnegiea (1 seedling, 1.4%). The pattern of seedling mortality in relation to temperature and rain suggests that, after the initial flush of seed and seedling predation, drought and heat took a greater toll on Carnegiea than Ferocactus seedlings, probably because the larger seedling volume of Ferocactus conferred greater drought tolerance. In addition, F. wislizeni could become established without benefit of nurse plants whereas C. gigantea could not; this might reflect differential tolerance to high soil temperatures.

  6. Effects of invasive rats and burrowing seabirds on seeds and seedlings on New Zealand islands.

    Science.gov (United States)

    Grant-Hoffman, Madeline N; Mulder, Christa P H; Bellingham, Peter J

    2010-04-01

    Rats (Rattus rattus, Rattus norvegicus, Rattus exulans) are important invaders on islands. They alter vegetation indirectly by preying on burrowing seabirds. These seabirds affect vegetation through nutrient inputs from sea to land and physical disturbance through trampling and burrowing. Rats also directly affect vegetation though consumption of seeds and seedlings. Seedling communities on northern New Zealand islands differ in composition and densities among islands which have never been invaded by rats, are currently invaded by rats, or from which rats have been eradicated. We conducted experimental investigations to determine the mechanisms driving these patterns. When the physical disturbance of seabirds was removed, in soils collected from islands and inside exclosures, seedling densities increased with seabird burrow density. For example, seedling densities inside exclosures were 10 times greater than those outside. Thus the negative effects of seabirds on seedlings, by trampling and uprooting, overwhelm the potentially beneficial effects of high levels of seed germination, seedling emergence, and possibly seed production, which result from seed burial and nutrient additions. Potential seedling density was reduced on an island where rats were present, germination of seeds from soils of this island was approximately half that found on other islands, but on this island seedling density inside exclosures was 7 times the density outside. Although the total negative effects of seabirds and rats on seedling densities are similar (reduced seedling density), the differences in mechanisms and life stages affected result in very different filters on the plant community.

  7. Effects of Seedbed Density on Seedling Morphological Characteristics of four Broadleaved Species

    Energy Technology Data Exchange (ETDEWEB)

    Yucedag, C.; Gailing, O.

    2012-11-01

    The aim of this study was to investigate the effects of seedling spacing on morphological characteristics of one year-old Amygdalus communis L., Prunus avium L., Pyrus elaeagnifolia Pall. and Eriolobus trilobatus (Poiret) Roemer seedlings under nursery conditions. Seedlings were grown in completely randomized blocks with four replications. Seedbeds were 1.2 m wide with 5 rows each 20 cm apart. Within-row spacings were chosen as 4, 8 and 12 cm to analyze the effect of seedlings density on growth performance. Seedling spacing significantly affected root collar diameter, shoot height, tap root length and number of fine roots in A. communis and P. avium, but not in P. elaeagnifolia and E. tribolatus. Additionally wider seedling spacings resulted in larger seedlings in A. communis and P. avium. In conclusion, it would be beneficial to use wider seedling spacing in order to obtain better seedling growth in A. communis and P. avium. Larger seedlings could also provide significant advantages because of reduced cultural activities and an expected higher growth and survival rate. (Author) 27 refs.

  8. Colonization with Arbuscular Mycorrhizal Fungi Promotes the Growth of Morus alba L. Seedlings under Greenhouse Conditions

    Directory of Open Access Journals (Sweden)

    Nan Lu

    2015-03-01

    Full Text Available Morus alba L. is an important tree species planted widely in China because of its economic value. In this report, we investigated the influence of two arbuscular mycorrhizal fungal (AMF species, Glomus mosseae and Glomus intraradices, alone and together, on the growth of M. alba L. seedlings under greenhouse conditions. The growth parameters and physiological performance of M. alba L. seedlings were evaluated 90 days after colonization with the fungi. The growth and physiological performance of M. alba L. seedlings were significantly affected by the AMF species. The mycorrhizal seedlings were taller, had longer roots, more leaves and a greater biomass than the non-mycorrhizae-treated seedlings. In addition, the AMF species-inoculated seedlings had increased root activity and a higher chlorophyll content compared to non-inoculated seedlings. Furthermore, AMF species colonization increased the phosphorus and nitrogen contents of the seedlings. In addition, simultaneous root colonization by the two AMF species did not improve the growth of M. alba L. seedlings compared with inoculation with either species alone. Based on these results, these AMF species may be applicable to mulberry seedling cultivation.

  9. Phenylalanine is required to promote specific developmental responses and prevents cellular damage in response to ultraviolet light in soybean (Glycine max) during the seed-to-seedling transition.

    Science.gov (United States)

    Sullivan, Joe H; Muhammad, DurreShahwar; Warpeha, Katherine M

    2014-01-01

    UV-radiation elicits a suite of developmental (photomorphogenic) and protective responses in plants, but responses early post-germination have received little attention, particularly in intensively bred plants of economic importance. We examined germination, hypocotyl elongation, leaf pubescence and subcellular responses of germinating and/or etiolated soybean (Glycine max (L.) Merr.) seedlings in response to treatment with discrete wavelengths of UV-A or UV-B radiation. We demonstrate differential responses of germinating/young soybean seedlings to a range of UV wavelengths that indicate unique signal transduction mechanisms regulate UV-initiated responses. We have investigated how phenylalanine, a key substrate in the phenylpropanoid pathway, may be involved in these responses. Pubescence may be a key location for phenylalanine-derived protective compounds, as UV-B irradiation increased pubescence and accumulation of UV-absorbing compounds within primary leaf pubescence, visualized by microscopy and absorbance spectra. Mass spectrometry analysis of pubescence indicated that sinapic esters accumulate in the UV-irradiated hairs compared to unirradiated primary leaf tissue. Deleterious effects of some UV-B wavelengths on germination and seedling responses were reduced or entirely prevented by inclusion of phenylalanine in the growth media. Key effects of phenylalanine were not duplicated by tyrosine or tryptophan or sucrose, nor is the specificity of response due to the absorbance of phenylalanine itself. These results suggest that in the seed-to-seedling transition, phenylalanine may be a limiting factor in the development of initial mechanisms of UV protection in the developing leaf.

  10. Nutrient Limitation in Central Red Sea Mangroves

    KAUST Repository

    Almahasheer, Hanan

    2016-12-24

    As coastal plants that can survive in salt water, mangroves play an essential role in large marine ecosystems (LMEs). The Red Sea, where the growth of mangroves is stunted, is one of the least studied LMEs in the world. Mangroves along the Central Red Sea have characteristic heights of ~2 m, suggesting nutrient limitation. We assessed the nutrient status of mangrove stands in the Central Red Sea and conducted a fertilization experiment (N, P and Fe and various combinations thereof) on 4-week-old seedlings of Avicennia marina to identify limiting nutrients and stoichiometric effects. We measured height, number of leaves, number of nodes and root development at different time periods as well as the leaf content of C, N, P, Fe, and Chl a in the experimental seedlings. Height, number of nodes and number of leaves differed significantly among treatments. Iron treatment resulted in significantly taller plants compared with other nutrients, demonstrating that iron is the primary limiting nutrient in the tested mangrove population and confirming Liebig\\'s law of the minimum: iron addition alone yielded results comparable to those using complete fertilizer. This result is consistent with the biogenic nature of the sediments in the Red Sea, which are dominated by carbonates, and the lack of riverine sources of iron.

  11. Invasive rats alter woody seedling composition on seabird-dominated islands in New Zealand.

    Science.gov (United States)

    Grant-Hoffman, Madeline N; Mulder, Christa P; Bellingham, Peter J

    2010-06-01

    Invasive rats (Rattus rattus, R. norvegicus, R. exulans) have large impacts on island habitats through both direct and indirect effects on plants. Rats affect vegetation by extirpating burrowing seabirds through consumption of eggs, chicks, and adults. These seabirds serve as ecosystem engineers, affecting plant communities by burying and trampling seeds and seedlings, and by altering microclimate. Rats also directly affect plant communities by consuming seeds and seedlings. We studied the direct and indirect impacts of rats on the seedlings of woody plants on 21 islands in northern New Zealand. We compared seedling densities and richness on islands which differed in status with respect to rats: nine islands where rats never invaded, seven islands where rats were present at the time of our study, and five islands where rats were either eradicated or where populations were likely to be small as a result of repeated eradications and re-invasions. In addition, we compared plots from a subset of the 21 islands with different burrow densities to examine the effects of burrowing seabirds on plants while controlling for other factors that differ between islands. We categorized plant communities by species composition and seedling density in a cluster analysis. We found that burrow densities explained more variation in seedling communities than rat status. In areas with high seabird burrow density seedling densities were low, especially for the smallest seedlings. Species richness and diversity of seedlings, but not seedling density, were most influenced by changes in microclimate induced by seabirds. Islands where rats had been eradicated or that had low rat populations had the lowest diversity and richness of seedlings (and adults), but the highest seedling density. Seedling communities on these islands were dominated by Pseudopanax lessonii and Coprosma macrocarpa. This indicates lasting effects of rats that may prevent islands from returning to pre-invasion states.

  12. The role of genetic and chemical variation of Pinus sylvestris seedlings in influencing slug herbivory.

    Science.gov (United States)

    O'Reilly-Wapstra, Julianne M; Iason, Glenn R; Thoss, Vera

    2007-05-01

    This study investigated the genetic and chemical basis of resistance of Pinus sylvestris seedlings to herbivory by a generalist mollusc, Arion ater. Using feeding trials with captive animals, we examined selective herbivory by A. ater of young P. sylvestris seedlings of different genotypes and correlated preferences with seedling monoterpene levels. We also investigated the feeding responses of A. ater to artificial diets laced with two monoterpenes, Delta(3)-carene and alpha-pinene. Logistic regression indicated that two factors were the best predictors of whether seedlings in the trial would be consumed. Individual slug variation (replicates) was the most significant factor in the model; however, alpha-pinene concentration (also representing beta-pinene, Delta(3)-carene and total monoterpenes due to multicollinearity) of needles was also a significant factor. While A. ater did not select seedlings on the basis of family, seedlings not eaten were significantly higher in levels of alpha-pinene compared to seedlings that were consumed. We also demonstrated significant genetic variation in alpha-pinene concentration of seedlings between different families of P. sylvestris. Nitrogen and three morphological seedling characteristics (stem length, needle length and stem diameter) also showed significant genetic variation between P. sylvestris families. Artificial diets laced with high (5 mg g(-1) dry matter) quantities of either Delta(3)-carene or alpha-pinene, were eaten significantly less than control diets with no added monoterpenes, supporting the results of the seedling feeding trial. This study demonstrates that A. ater selectively feed on P. sylvestris seedlings and that this selection is based, in part, on the monoterpene concentration of seedlings. These results, coupled with significant genetic variation in alpha-pinene concentration of seedlings and evidence that slug herbivory is detrimental to P. sylvestris fitness, are discussed as possible evidence for A

  13. Production and characterization of monoclonal antibodies to wall-localized peroxidases from corn seedlings

    Science.gov (United States)

    Kim, S. H.; Terry, M. E.; Hoops, P.; Dauwalder, M.; Roux, S. J.

    1988-01-01

    A library of 22 hybridomas, which make antibodies to soluble wall antigens from the coleoptiles and primary leaves of etiolated corn (Zea mays L.) seedlings, was raised and cloned three times by limit dilution to assure monoclonal growth and stability. Two of these hybridomas made immunoglobulin G antibodies, designated mWP3 and mWP19, which both effectively immunoprecipitated peroxidase activity from crude and partially purified preparations of wall peroxidases. Direct peroxidase-binding assays revealed that both antibodies bound enzymes with peroxidase activity. As judged by immunoblot analyses, mWP3 recognized a Mr 98,000 wall peroxidase with an isoelectric point near 4.2, and mWP19 recognized a Mr 58,000 wall peroxidase. Immunogold localization studies showed both peroxidases are predominately in cell walls.

  14. Future heat waves due to climate change threaten the survival of Posidonia oceanica seedlings.

    Science.gov (United States)

    Guerrero-Meseguer, Laura; Marín, Arnaldo; Sanz-Lázaro, Carlos

    2017-11-01

    Extreme weather events are major drivers of ecological change, and their occurrence is likely to increase due to climate change. The transient increases in atmospheric temperatures are leading to a greater occurrence of heat waves, extreme events that can produce a substantial warming of water, especially in enclosed basins such as the Mediterranean Sea. Here, we tested the effects of current and predicted heat waves on the early stages of development of the seagrass Posidonia oceanica. Temperatures above 27 °C limited the growth of the plant by inhibiting its photosynthetic system. It suffered a reduction in leaf growth and faster leaf senescence, and in some cases mortality. This study demonstrates that the greater frequency of heat waves, along with anticipated temperature rises in coming decades, are expected to negatively affect the germination of P. oceanica seedlings. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Production and characterization of monoclonal antibodies to wall-localized peroxidases from corn seedlings

    Science.gov (United States)

    Kim, S. H.; Terry, M. E.; Hoops, P.; Dauwalder, M.; Roux, S. J.

    1988-01-01

    A library of 22 hybridomas, which make antibodies to soluble wall antigens from the coleoptiles and primary leaves of etiolated corn (Zea mays L.) seedlings, was raised and cloned three times by limit dilution to assure monoclonal growth and stability. Two of these hybridomas made immunoglobulin G antibodies, designated mWP3 and mWP19, which both effectively immunoprecipitated peroxidase activity from crude and partially purified preparations of wall peroxidases. Direct peroxidase-binding assays revealed that both antibodies bound enzymes with peroxidase activity. As judged by immunoblot analyses, mWP3 recognized a Mr 98,000 wall peroxidase with an isoelectric point near 4.2, and mWP19 recognized a Mr 58,000 wall peroxidase. Immunogold localization studies showed both peroxidases are predominately in cell walls.

  16. Responses of Tree Seedlings to a Changing Atmosphere: Effects of Carbon Dioxide, Nitrogen Dioxide, and Ozone

    Science.gov (United States)

    Eller, A. S.; Sparks, J. P.

    2008-12-01

    Human activities have caused changes in the chemical composition of the atmosphere: the concentrations of carbon dioxide (CO2), nitrogen dioxide (NO2), and ozone (O3) have increased and are expected to continue increasing in the future. These gases have the potential to alter plant physiological processes, change growth rates, C:N, and carbon storage potential. The responses of tree seedlings to these changes will have a profound impact on the species composition and carbon storage potential of forests in the future. Others have found CO2 tends to increase plant growth and O3 to decrease it. NO2, if assimilated by plants, can be a source of nutrient nitrogen, but is also an oxidant with the potential to damage cell membranes and decrease growth. The objectives of this study were to determine the single and combined effects of CO2, NO2, and O3 on sugar maple, eastern hemlock, and two clones of trembling aspen. The trees were fumigated for two growing seasons with elevated (40ppb) or ambient NO2, elevated (560ppm) or ambient CO2, elevated (100 ppb 5 days/week) or ambient O3, and with or without additional soil nitrate (30 kg ha-1 yr-1) to simulate ecosystems with and without nitrogen limitation. We found that elevated CO2 increased total biomass of both maples and hemlocks. Further, the CO2 growth effect was most striking when combined with elevated O2; elevated CO2 eliminated the growth decrease induced by O3 especially when nitrogen was limited. Elevated NO2 had no effect on maple seedlings, but, similar to CO2, eliminated the decrease in growth under O3 on hemlock seedlings. The two aspen clones differed in their resistance to ozone. The non-resistant clone exhibited growth responses similar to maple. However, the resistant clone did not exhibit a growth response under any gas treatment regardless of soil nitrogen status. The variation in responses among species, within clones of the same species, and between fumigations was large in this study and suggests

  17. Clinorotation affects mesophyll photosynthetic cells in leaves of pea seedlings.

    Science.gov (United States)

    Adamchuk, N I

    1998-07-01

    Experiments with autotrophs in altered gravity condition have a grate significant for development of space biology. The main results of investigation in the photosynthetic apparatus state under microgravity condition have based on the experiments with maturity plants and their differentiated cells. The structural and functional organization of photosynthetic cells in seedlings is poor understandable still. Along with chloroplasts preserving a native membrane system in palisade parenchyma cells of the 29-day pea plant leaves in microgravity, chloroplasts with fribly packed or damaged granae, whose thylakoids appeared as vesicles with an electrontransparent content, were also observed. The investigation of preceding process induced these effects have a sense. That is why, the goal of our experiments was to perform the study of a structural organization of the photosynthetic cells of 3-d pair of pea seedlings leaves under the influence of clinorotation.

  18. Starch bioengineering affects cereal grain germination and seedling establishment

    DEFF Research Database (Denmark)

    Shaik, Shahnoor Sultana; Carciofi, Massimiliano; Martens, Helle Juel;

    2014-01-01

    Cereal grain germination is central for plant early development, and efficient germination has a major role in crop propagation and malting. Endosperm starch is the prime energy reserve in germination and seedling establishment. In this study, it was hypothesized that optimized starch granule...... structure, and not only the endosperm starch content per se, is important for germination and seedling establishment. For that purpose, wild-type (WT), and specifically engineered degradable hyperphosphorylated (HP) starch and more resistant amylose-only (AO) starch barley lines were used. The transgenics...... showed no severe phenotypes and the WT and HP lines degraded the starch similarly, having 30% residual starch after 12 d of germination. However, the AO line showed significant resistance to degradation, having 57% residual starch. Interestingly, protein and β-glucan (BG) degradation was stimulated...

  19. Architectural ideotype of pear seedling in five hybrid combinations

    Directory of Open Access Journals (Sweden)

    Vasile GHIDRA

    1998-08-01

    Full Text Available The architectural ideotype - type of growing - was studied in a topcross experiment with five hybrid combinations in which Cluj 72-2-100 selection, typical spur, was used as a maternal tester. The analyzed seedlings were at the end of their sixth year of vegetation. There were no significant differences among the five hybrid combinations concerning the distributions of F1 seedling in the four accepted ideotypes (columnar, spur, standard, and weeping. A high variability was found for ideotype (between 18.8% in Cluj 72-2-100 x Napoca and 34.4% in Cluj 72-2-100 x Red Bartlett. The participation rate of genotype in the phenotypic manifestation of this character is relatively low. The coefficient of heritability in broad sense was 0.29 and the coefficient of heritability in narrow sense was very low, 0.001.

  20. QUALITY EVALUATION OF Cedrela fissilis SEEDS AND SEEDLINGS

    Directory of Open Access Journals (Sweden)

    Edicléia Aparecida Iensen Cherobini

    2009-10-01

    Full Text Available Belonging to the Meliaceae family, cedro (Cedrela fissilis Vell. presents a great economical and ecological importance. The wood is light and easy to work, being suggested to the manufacturing of furniture in general, also it is used to reset degraded areas. The objective of this work was to evaluate the quality of Cedrela fissilis seedlings and seeds from Rio Grande do Sul, Santa Catarina and Paraná, through the accomplishment of varied tests of vigor, test of health and evaluation of the quality of seedlings produced from these seeds. The present study showed that the presence of fungi pathological potential – Aspergillus spp. and Penicillium spp. – can cause losses in the germination. Considering tests with seeds collected in the different states of the South Region, it was possible to verify that differences of the vigor levels exist. The fungi found in the seeds can cause damages in the production.

  1. Arabidopsis plastidial folylpolyglutamate synthetase is required for seed reserve accumulation and seedling establishment in darkness.

    Directory of Open Access Journals (Sweden)

    Hongyan Meng

    Full Text Available Interactions among metabolic pathways are important in plant biology. At present, not much is known about how folate metabolism affects other metabolic pathways in plants. Here we report a T-DNA insertion mutant (atdfb-3 of the plastidial folylpolyglutamate synthetase gene (AtDFB was defective in seed reserves and skotomorphogenesis. Lower carbon (C and higher nitrogen (N content in the mutant seeds than that of the wild type were indicative of an altered C and N partitioning capacity. Higher levels of organic acids and sugars were detected in the mutant seeds compared with the wild type. Further analysis revealed that atdfb-3 seeds contained less total amino acids and individual Asn and Glu as well as NO3-. These results indicate significant changes in seed storage in the mutant. Defects in hypocotyl elongation were observed in atdfb-3 in darkness under sufficient NO3- conditions, and further enhanced under NO3- limited conditions. The strong expression of AtDFB in cotyledons and hypocotyl during early developmental stage was consistent with the mutant sensitivity to limited NO3- during a narrow developmental window. Exogenous 5-formyl-tetrahydrofolate completely restored the hypocotyl length in atdfb-3 seedlings with NO3- as the sole N source. Further study demonstrated that folate profiling and N metabolism were perturbed in atdfb-3 etiolated seedlings. The activity of enzymes involved in N reduction and assimilation was altered in atdfb-3. Taken together, these results indicate that AtDFB is required for seed reserves, hypocotyl elongation and N metabolism in darkness, providing novel insights into potential associations of folate metabolism with seed reserve accumulation, N metabolism and hypocotyl development in Arabidopsis.

  2. Termite biocontrol on cacao seedling: Vetiver grass application

    OpenAIRE

    Du, Le; Truc, N.H.

    2008-01-01

    Just in the last decade, cacao (Theobroma cacao) has been introduced to the agroforestry systems in some upland provinces of southern Vietnam, especially in cashew plantation for improving the income of local farmers. However termite attack on cacao seedlings is the main constraint to the development of this crop in these systems. Chemical application is the only method available for farmers to protect their cacao crop. So far there is no study on non-chemical termite control method. An exper...

  3. Growth responses of Picea mongolica seedlings to defoliation rate

    Institute of Scientific and Technical Information of China (English)

    ZOU Chun-jing; HAN Shi-jie; QI Shu-yan; XU Wen-duo; LI Dao-tang

    2005-01-01

    Picea mongolica W. D. Xu. is an endemic species in China. The spruce forest is only found in semi-arid habitat in Inner Mongolia Autonomous Region of China. Based on the simulative defoliation experiment, it was proved that Picea mongolica seedlings had the compensatory and overcompensatory effects under the certain defoliation rate. The results of variance analysis on growth indexes showed that in PM Ⅰ (natural regeneration seedlings under Picea mongolica forest), the differences of H1 (height in June 23) and H2 (height in September 3) were extremely significant, and the difference of D(diameter at the breast height) were not significant. In PM Ⅱ (artificial regeneration seedlings under Betula platyphylla Suk. forest), the difference of H1 was significant, the difference of H2 was not significant, and the difference of D was extremely significant. The regression equations were established and the compensatory and overcompensatory points were obtained. In PM Ⅰ , the compensatory points of H1, H2, and D were 0.7628, 0.7436, 0.5725, and the overcompensatory points were 0.6056, 0.5802 and 0.2909 respectively. In PM Ⅱ, the compensatory points of H1, H2, and D are 0.5012, 0.3421, 0.2488, and the overcompensatory points are 0.4137, 0.2633 and 0.0747 respectively. These results suggested that the induction of compensatory growth mechanisms in spruce seedlings required a threshold level of defoliation, and the insects in Picea mongolica forest could be controlled in a certain degree.

  4. Evaluating first-year pine seedling survival plateau in Louisiana

    Science.gov (United States)

    Puskar N. Khana; Thomas J. Dean; Scott D. Roberts; Donald L. Grebner

    2016-01-01

    First-year seeding survival has been a continuing problem since the start of commercial pine plantation forestry in the 1950s. First-year survival of bare-root loblolly pine seedlings on intensively prepared sites in Louisiana has maintained a survival plateau between 79 to 89 percent with an average of about 82 percent. The specific objectives of this study were to...

  5. Cork oak (Quercus suber L.) seedlings acclimate to elevated

    OpenAIRE

    2012-01-01

    Leaf gas-exchange, leaf and shoot anatomy, wood density and hydraulic conductivity were investigated in seedlings of Quercus suber L. grown for 15 months either at elevated (700 lmol mol-1) or normal (350 lmol mol-1) ambient atmospheric CO2 concentrations. Plants were grown in greenhouses in a controlled environment: relative humidity 50% (±5), temperature similar to external temperature and natural light conditions. Plants were supplied with nutrients and two water re...

  6. Chloroplasts in seeds and dark-grown seedlings of lotus.

    Science.gov (United States)

    Ushimaru, Takashi; Hasegawa, Takahiro; Amano, Toyoki; Katayama, Masao; Tanaka, Shigeyasu; Tsuji, Hideo

    2003-03-01

    In most higher plants, mature dry seeds have no chloroplasts but etioplasts. Here we show that in a hydrophyte, lotus (Nelumbo nucifera), young chloroplasts already exist in shoots of mature dry seeds and that they give rise to mature chloroplasts during germination, even in darkness. These shoots contain chlorophyll and chlorophyll-binding proteins CP1 and LHCP. The unique features of chloroplast formation in N. nucifera suggest a unique adaptive strategy for seedling development correlated with the plant's habitat.

  7. THE EFFECT OF INDUSTRIAL WATER ON THE GERMINATION OF SEEDS AND THE DEVELOPMENT OF SEEDLINGS OF PISUM SATIVUM L.

    OpenAIRE

    Liliana Cristina SOARE; Codruţa-Mihaela DOBRESCU; Liana Elena LASCU

    2011-01-01

    The aim of the research was to highlight the influence of industrial water on the germination of seeds and the development of seedlings of Pisum sativum L., so that the impact of these water on the plants may be assessed, in case of accidental spills. The analysis of polluted industrial water indicates the presence of Cr, Fe, Ni, Pb, Cd, Cu, and Zn concentrations higher than CMA, except Cd, which was below the detection limit, and Cu. On leaving the neutralization station, metal concentration...

  8. Seedling Performance Associated with Live or Herbicide Treated Tall Fescue

    Directory of Open Access Journals (Sweden)

    Jonathan J. Halvorson

    2015-01-01

    Full Text Available Tall fescue is an important forage grass which can host systemic fungal endophytes. The association of host grass and endophyte is known to influence herbivore behavior and host plant competition for resources. Establishing legumes into existing tall fescue sods is a desirable means to acquire nitrogen and enhance the nutritive value of forage for livestock production. Competition from existing tall fescue typically must be controlled to ensure interseeding success. We used a soil-on-agar method to determine if soil from intact, living (L, or an herbicide killed (K tall fescue sward influenced germination and seedling growth of three cultivars of tall fescue (E+, MaxQ, and E− or legumes (alfalfa, red clover, and white clover. After 30 days, seedlings were larger and present in greater numbers when grown in L soil rather than K soil. Root growth of legumes (especially white clover and tall fescue (especially MaxQ were not as vigorous in K soil as L soil. While shoot biomass was similar for all cultivars of tall fescue in L soil, MaxQ produced less herbage when grown in K soil. Our data suggest establishing legumes or fescue cultivars may not be improved by first killing the existing fescue sod and seedling performance can exhibit significant interseasonal variation, related only to soil conditions.

  9. Endophytic fungi reduce leaf-cutting ant damage to seedlings.

    Science.gov (United States)

    Bittleston, L S; Brockmann, F; Wcislo, W; Van Bael, S A

    2011-02-23

    Our study examines how the mutualism between Atta colombica leaf-cutting ants and their cultivated fungus is influenced by the presence of diverse foliar endophytic fungi (endophytes) at high densities in tropical leaf tissues. We conducted laboratory choice trials in which ant colonies chose between Cordia alliodora seedlings with high (E(high)) or low (E(low)) densities of endophytes. The E(high) seedlings contained 5.5 times higher endophyte content and a greater diversity of fungal morphospecies than the E(low) treatment, and endophyte content was not correlated with leaf toughness or thickness. Leaf-cutting ants cut over 2.5 times the leaf area from E(low) relative to E(high) seedlings and had a tendency to recruit more ants to E(low) plants. Our findings suggest that leaf-cutting ants may incur costs from cutting and processing leaves with high endophyte loads, which could impact Neotropical forests by causing variable damage rates within plant communities.

  10. Gluconeogenesis from storage wax in the cotyledons of jojoba seedlings.

    Science.gov (United States)

    Moreau, R A; Huang, A H

    1977-08-01

    The cotyledons of jojoba (Simmondsia chinensis) seeds contained 50 to 60% of their weight as intracellular wax esters. During germination there was a gradual decrease in the wax content with a concomitant rise in soluble carbohydrates, suggesting that the wax played the role of a food reserve. Thin layer chromatography revealed that both the fatty alcohol and fatty acid were metabolized. The disappearance of wax was matched with an increase of catalase, a marker enzyme of the gluconeogenic process in other fatty seedlings. Subcellular organelles were isolated by sucrose gradient centrifugation from the cotyledons at the peak stage of germination. The enzymes of the beta oxidation of fatty acid and of the glyoxylate cycle were localized in the glyoxysomes but not in the mitochondria. The glyoxysomes had specific activities of individual enzymes similar to those of the castor bean glyoxysomes. An active alkaline lipase was detected in the wax bodies at the peak stage of germination but not in the ungerminated seeds. No lipase was detected in glyoxysomes or mitochondria. After the wax in the wax bodies had been extracted with diethyl ether, the organelle membrane was isolated and it still retained the alkaline lipase. The gluconeogenesis from wax in the jojoba seedling appears to be similar, but with modification, to that from triglyceride in other fatty seedlings.

  11. Fungi of the genus Fusarium as pathogens of soybean seedlings

    Directory of Open Access Journals (Sweden)

    Joanna Marcinkowska

    2013-12-01

    Full Text Available Twenty isolates of fungi of the genus Fusarium collected in the period 1980-1982 from various organs of diseased soybean plants were investigated. Eight of them proved pathogenic to soybean seedlings. The species F. culmorum was most numerously represented among the isolated (4 of 8 pathogens. Isolates of F. sambucinum were also pathogenic (2 of 4 and those of F. soloni (1 of 3, too. The only isolate of F. avenaceum also caused seedling blight. Two isolates of F. oxysporum and two of F. arthrosporioides were not pathogenic. Numerous isolates affected seed gernination and one greatly inhibited growth of the infected seedlings. Pathogenicity was tested in the laboratory in Petri plates on isolate cultures and on filter paper imbibed with fungal inoculum and, in the greenhouse on a peat and perlite substrate. The degree of infection and the character of the disease symptoms depended on the experimental conditions. The results of experiments in plates and in the greenhouse supplemented one another.

  12. [Thermal dissipation pathway in cucumber seedling leaves under hypoxia stress].

    Science.gov (United States)

    Jia, Yong-xi; Sun, Jin; Wang, Li-ping; Shu, Sheng; Guo, Shi-rong

    2011-03-01

    A water culture experiment was conducted to study the relationship between photosynthetic thermal dissipation and xanthophyll cycle in cucumber seedling leaves under hypoxia stress (the dissolved oxygen concentration in nutrient solution was 0.9-1.1 mg x L(-1)). Under the hypoxia stress, there was a significant decrease in the quantum yield of PS II photochemistry rate (phi(PS II)), net photosynthetic rate (Pn) under saturation light intensity, quanta yield (AQY), and maximal photochemical efficiency (Fv/Fm), suggesting that the photoinhibition of the seedling leaves was induced. Meanwhile, the thermal dissipation (NPQ) and the allocation of dissipation energy (D) by antenna increased, but the photochemical quenching apparent (q(p)) decreased, suggesting the enhancement of thermal dissipation in cucumber leaves under hypoxia stress. A positive correlation was observed between NPQ and xanthophyll de-epoxidation state (DEPS), and both of them were promoted by ascorbic acid (AsA) and inhibited by 1,4-dithiothreitol (DTT), suggesting that xanthophyll cycle was the major pathway of photosynthetic thermal dissipation in cucumber seedling leaves under hypoxia stress.

  13. Effects of gravel mulch on emergency of galleta grass seedlings

    Energy Technology Data Exchange (ETDEWEB)

    Winkel, V.K.; Medrano, J.C.; Stanley, C.; Walo, M.D.

    1993-02-01

    Gravel mulches show promise as effective material on the US Dept. of Energy Nevada Test Site for stabilizing erosive soils and aiding plant establishment by conserving soil water. A greenhouse study was implemented to determine the effects of gravel mulch on seedling emergence and soil water, and optimal depths of gravel for various native plant species. Greenhouse flats were sown with seeds of nine species of native grasses, forbs, and shrubs. The flats were then treated with a variety of mulch treatments including, no mulch, a 1-cm layer of soil over seeds, and 2 to 3-cm and 4 to 5-cm layers of 3 to 25-mm mixed gravel. Superimposed over these treatments were 3 irrigation treatments. Seedling density data was collected daily, and soil water was monitored daily with the gravimetric method. This study showed that under a variety of soil water conditions, a 2--3 cm gravel layer may aid emergence of galleta grass. Results from this study also demonstrated that a deeper layer of gravel (4--5 cm) prohibits emergence, probably because it acts as a physical barrier to the seedlings. Galleta grass emergence can be used as a model for how other species might respond to these seedbed and irrigation treatments, provided they have adequate germination and are exposed to similar environmental conditions.

  14. Evaluation of Oxygen Deficit Stress on Germination Indicators and Seedling

    Directory of Open Access Journals (Sweden)

    F Hoseini

    2012-06-01

    Full Text Available To investigate the relationship oxygen deficit stress on germination indicators and seedling growth of five wheat cultivars in laboratory condition, an experiment with Randomized Complete Block design in factorial arrangement with three replications was conducted in 2008. The treatments consisted of five wheat cultivars (Chamran, Flat, Roshan, Stare and Shole as A factor, and two oxygen level (normal seed and seed under oxygen deficit stress conditions as B factor in each of these figures was done. Results showed that oxygen deficit stress caused to decrease for various cultivars germination percentage, germination rate, allometric coefficient, seed vigor index and other germination indicators. Therefore, this test as a suitable method for determining the quality of various seed lot can be used in the water logging condition. In addition, among different cultivars characterized that Roshan cultivar was more resistant to oxygen deficit stress than Chamran, Flat and Star cultivars. Although Chamran cultivar is common cultivar in Khouzestan, but of look most germination indicators arranged as weak seed class. The highest correlation coefficients among the tested cultivars have been related to seed vigor with seedling length and dry weight of radicle with seedling with 0.92 and 0.90, respectively.

  15. Morphogenesis of rice and Arabidopsis seedlings in space.

    Science.gov (United States)

    Hoson, T; Soga, K; Mori, R; Saiki, M; Wakabayashi, K; Kamisaka, S; Kamigaichi, S; Aizawa, S; Yoshizaki, I; Mukai, C; Shimazu, T; Fukui, K; Yamashita, M

    1999-12-01

    Seedlings of rice (Oryza saliva L.) and Arabidopsis (A. thaliana L.) were cultivated for 68.5 hr in the RICE experiment on board during Space Shuttle STS 95 mission, and changes in their growth and morphology were analyzed. Microgravity in space stimulated elongation growth of both rice coleoptiles and Arabidopsis hypocotyls by making their cell walls extensible. In space, rice coleoptiles showed an inclination toward the caryopsis in the basal region and also a spontaneous curvature in the same direction in the elongating region. These inclinations and curvatures were more prominent in the Koshihikari cultivar compared to a dwarf cultivar, Tan-ginbozu. Rice roots elongated in various directions including into the air on orbit, but two thirds of the roots formed a constant angle with the axis of the caryopsis. In space, Arabidopsis hypocotyls also elongated in a variety of directions and about 10% of the hypocotyls grew into the agar medium. No clear curvatures were observed in the elongating region of Arabidopsis hypocotyls. Such a morphology of both types of seedlings was fundamentally similar to that observed on a 3 D clinostat. Thus, it was confirmed by the RICE experiment that rice and Arabidopsis seedlings perform an automorphogenesis under not only simulated but also true microgravity conditions.

  16. GAS EXCHANGE AND CARBOHYDRATE PARTITIONING IN COFFEE SEEDLINGS UNDER WATERLOGGING

    Directory of Open Access Journals (Sweden)

    Helbert Rezende de Oliveira Silveira

    2015-04-01

    Full Text Available Irrigation has enhanced coffee production in several regions of Brazil. However, with the increase in irrigated crop areas, problems related to the frequent and poorly planned usage of irrigation may arise. Since there are few studies related to the physiological alterations in coffee plants exposed to water excess, we evaluated the effects of waterlogging on metabolism and partitioning of carbohydrates, levels of photosynthetic pigments and gas exchange in seedlings of two commercial coffee cultivars (Mundo Novo and Catuaí. After acclimation, seedlings with eight pairs of fully expanded leaves were cultivated under three water availability conditions: field capacity, intermittent waterlogging and continuous waterlogging. Gas exchange and the levels of chlorophyll, carotenoids and carbohydrates were evaluated during the five months after the beginning of the treatments. Waterlogging reduced the rates of photosynthesis and transpiration, leading to lower activity of the carboxylative step of photosynthesis and culminating in the reduction of carbohydrate partitioning in coffee seedlings. Although many physiological parameters were affected by waterlogging, the cultivars in our study survived for five months under stressful conditions.

  17. Limits on $\

    CERN Document Server

    Perego, D L

    2002-01-01

    A limit on the tau neutrino mass is obtained using all the $Z^{0} \\to \\tau^{+} \\tau^{-}$ data collected at LEP by the DELPHI detector between 1992 and 1995. In this analysis events in which one of the taus decays into one charged particle, while the second $\\tau$ decays into f{}ive charged pions (1-5 topology) have been used. The neutrino mass is determined from a bidimensional \\fit ~on the invariant mass $m^{*}_{5 \\pi}$ and on the energy $E_{5 \\pi}$ of the f{}ive $\\pi^{\\pm}$ system. The result found is $m_{\

  18. Effects of tip-pruning treatment on source-sink regulation of Catharanthus roseus seedlings

    Institute of Scientific and Technical Information of China (English)

    GAO Yang; ZHANG Xue-ke; GUO Xiao-rui; SUN Yan-fei; ZU Yuang-gang

    2006-01-01

    Fifty cultivated Catharanthus roseus seedlings were selected for tip-pruning treatment and the effects of tip-pruning on seedling growth and source-sink regulation were investigated for revealing physiological mechanisms of plants. The results showed that tip-pruning treatment resulted in obvious inhibition of apical dominance and enhancement of branching numbers. The contents of soluble sugars, acid sucrose invertase activity (AI) had a great change in differently positional leaves of the seedling. The sink strength in tip leaves of seedlings dramatically declined after tip-pruning treatment, while that in the leaves at the middle and bottom of seedlings had no obvious changes. The inhibition of apical dominance of tip leaves of seedlings was caused by the diminished sink strength due to tip-pruning treatment,

  19. Effects of Ectomycorrhizal Fungi on Growth of Seedlings of Pinus densiflora.

    Science.gov (United States)

    Sim, Mi-Yeong; Eom, Ahn-Heum

    2006-12-01

    This study was conducted to investigate the different effects of ectomycorrhizal fungal (ECMF) species on the growth of seedlings of Pinus densiflora, and the effects of ECMF diversity on plant productivity. A total of five species of ECMF were isolated from root tips of pine seedlings collected from Mt. Songni and used as inocula. Pots containing pine seedlings were inoculated with either a single ECMF species or a mixture of five ECMF species. All of the seedlings formed ECM on their roots except for the control plants. The pine seedlings' growth responses varied by the different ECMF species. Also, pine seedlings inoculated with a mixture of five ECMF species showed the highest growth response. The results of the study suggest that the colonization of diverse species of ECMF will increase plant productivity, and the selection of suitable ECMF species could be an important factor for plant growth.

  20. Growth response of Pinus densiflora seedlings inoculated with three indigenous ectomycorrhizal fungi in combination

    Directory of Open Access Journals (Sweden)

    M Dalong

    2011-09-01

    Full Text Available Pinus densiflora seedlings were inoculated with three indigenous ectomycorrhizal fungi (Cenococcum geophilum, Rhizopogon roseolus and Russula densifolia in single-, two-, and three-species treatments. After 8 months, the colonization rates of each ectomycorrhizal species, seedling growth and the nutrition were assessed in each treatment. P. densiflora seedlings inoculated with different ECM species composition showed an increase in height and basal diameter and improved seedling root and shoot nutrition concentrations compared to control treatment. Generally, combined inoculation had a more positive influence on the seedlings than the single inoculation. The three-species inoculation presented the highest growth and basal diameter and concentration of most nutrients except potassium. In conclusion, the results provided strong evidence for benefits of combined inoculation with the indigenous ectomycorrhizal fungi on P. densiflora seedlings under controlled conditions.

  1. Growth response of Pinus densiflora seedlings inoculated with three indigenous ectomycorrhizal fungi in combination.

    Science.gov (United States)

    Dalong, M; Luhe, W; Guoting, Y; Liqiang, M; Chun, L

    2011-07-01

    Pinus densiflora seedlings were inoculated with three indigenous ectomycorrhizal fungi (Cenococcum geophilum, Rhizopogon roseolus and Russula densifolia) in single-, two-, and three-species treatments. After 8 months, the colonization rates of each ectomycorrhizal species, seedling growth and the nutrition were assessed in each treatment. P. densiflora seedlings inoculated with different ECM species composition showed an increase in height and basal diameter and improved seedling root and shoot nutrition concentrations compared to control treatment. Generally, combined inoculation had a more positive influence on the seedlings than the single inoculation. The three-species inoculation presented the highest growth and basal diameter and concentration of most nutrients except potassium. In conclusion, the results provided strong evidence for benefits of combined inoculation with the indigenous ectomycorrhizal fungi on P. densiflora seedlings under controlled conditions.

  2. Biochemical contents of pepper seedlings inoculated with phytophthora infestans and arbuscular mycorrhiza

    Directory of Open Access Journals (Sweden)

    Odebode A.C.

    2004-01-01

    Full Text Available The effect of interactions between Arbuscular Glomus etunicatum and fungus Phytophthora infestans on biochemical contents of pepper plants was investigated in a greenhouse experiment. The sugar contents (i.e. Glucose fructose and sucrose were higher in the control and mycorrhizal inoculated pepper seedlings and the lowest in pathogen inoculated seedlings. Free amino acids were the highest in the simultaneously inoculated pepper seedlings while total phenol was found to be the highest in pepper seedlings inoculated with P. infestans. The levels of nitrogen, phosphorus and potassium varied in the inoculated pepper seedlings without any significant difference in the treatment. The results obtained suggest protective influence of mycorrhiza by enhancing the nutritional status of the inoculated pepper seedlings.

  3. Root graviresponsiveness and columella cell structure in carotenoid-deficient seedlings of Zea mays

    Science.gov (United States)

    Moore, R.; McClelen, C. E.

    1985-01-01

    Root graviresponsiveness in normal and carotenoid-deficient mutant seedlings of Zea mays was not significantly different. Columella cells in roots of mutant seedlings were characterized by fewer, smaller, and a reduced relative volume of plastids as compared to columella cells of normal seedlings. Plastids in columella cells of mutant seedlings possessed reduced amounts of starch. Although approximately 10 per cent of the columella cells in mutant seedlings lacked starch, their plastids were located at the bottom of the cell. These results suggest that (i) carotenoids are not necessary for root gravitropism, (ii) graviresponsiveness is not necessarily proportional to the size, number, or relative volume of plastids in columella cells, and (iii) sedimentation of plastids in columella cells may not result directly from their increased density due to starch content. Plastids in columella cells of normal and mutant seedlings were associated with bands of microtubule-like structures, suggesting that these structures may be involved in 'positioning' plastids in the cell.

  4. Przebieg mitozy w korzeniach siewek pszenicy pod wpływem rubidu [Course of mitosis in root seedlings of Triticum aestivum L. under the influence of rubidium

    Directory of Open Access Journals (Sweden)

    Kazimierz Olech

    2015-06-01

    Full Text Available The depresion of mitosis as a result of rubidium action illustrated by the lower frequency of mitosis was found in an investigation made on roots of wheat seedlings grown on a nutrient medium which the total amount of potassium or a half of it was replaced by rubidium. The lower mitotic activity was caused by limited number of nuclei beginning prophase and by a prolonged duration of metaphase.

  5. Cation Uptake and Allocation by Red Pine Seedlings under Cation-Nutrient Stress in a Column Growth Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Zhenqing; Balogh-Brunstad, Zsuzsanna; Grant, Michael R.; Harsh, James B.; Gill, Richard; Thomashow, Linda; Dohnalkova, Alice; Stacks, Daryl; Letourneau, Melissa; Keller, Chester K.

    2014-01-10

    Background and Aims Plant nutrient uptake is affected by environmental stress, but how plants respond to cation-nutrient stress is poorly understood. We assessed the impact of varying degrees of cation-nutrient limitation on cation uptake in an experimental plant-mineral system. Methods Column experiments, with red pine (Pinus resinosa Ait.) seedlings growing in sand/mineral mixtures, were conducted for up to nine months under a range of Ca- and K-limited conditions. The Ca and K were supplied from both minerals and nutrient solutions with varying Ca and K concentrations. Results Cation nutrient stress had little impact on carbon allocation after nine months of plant growth and K was the limiting nutrient for biomass production. The Ca/Sr and K/Rb ratio results allowed independent estimation of dissolution incongruency and discrimination against Sr and Rb during cation uptake processes. The fraction of K in biomass from biotite increased with decreasing K supply from nutrient solutions. The mineral anorthite was consistently the major source of Ca, regardless of nutrient treatment. Conclusions Red pine seedlings exploited more mineral K in response to more severe K deficiency. This did not occur for Ca. Plant discrimination factors must be carefully considered to accurately identify nutrient sources using cation tracers.

  6. Quality assessment of truffle-inoculated seedlings in Italy: proposing revised parameters for certification

    Directory of Open Access Journals (Sweden)

    Domizia Donnini

    2014-08-01

    Full Text Available Aim of study: the main aims of this study were to evaluate the quality of truffle-inoculated seedlings produced by commercial nurseries in Italy and to identify their minimum requisites in terms of plant age, health, homogeneity, and cut-off percentage of inoculated Tuber and non-Tuber ectomycorrhizae, based on the analysis of an extensive sample of seedlings subjected to quality control and certification.Area of study: truffle-inoculated seedlings produced by Italian commercial nurseries.Material and Methods: analysis of truffle-inoculated seedlings for health and quality standards; recording of presence of inoculated Tuber spp. and other concurrent fungi according to the official Italian method for certification; selective amplification of ectomycorrhizal DNA by PCR species-specific primers.Main results: We showed that mycorrhization levels in truffle-inoculated seedlings increased with time after truffle-spore inoculation. The highest mean percentage of the inoculated Tuber spp., but also the highest presence of contaminants, were recorded after three years. The mycorrhization level of Tuber melanosporum and T. aestivum was higher in Corylus and Ostrya seedlings than in Q. ilex and Q. pubescens, but the latter two host species showed the lowest presence of other ectomycorrhizal fungi. Mycorrhization level distribution in truffle-inoculated seedlings of suitable batches differed very little from the distribution in only all suitable seedlings. Truffle seedlings with other Tuber spp. were very few and even absent after three years. The general quality of Italian truffle-inoculated seedlings is high but can be improved even further by revising the parameters used for their certification.Research highlights: Mycorrhization assessment in truffle-inoculated seedlings produced by commercial nurseries and a revision of the parameters of quality standards following several years of certification in Italy.Keywords: Truffle cultivation; truffle

  7. Characteristics of water relations in seedling of Machilus yunnanensis and Cinnamomum camphora under soil drought condition

    Institute of Scientific and Technical Information of China (English)

    TANG Tian-tian; ZHAO Lin-sen

    2006-01-01

    The soil drought stress experiment in different durations (no watering within 3d, 6d, 9d, 11d individually) was conducted to study the drought-resistant capacity of one-year-old seedlings for the native tree species (Machilus yunnanensis) in Yunnan Province and the introduced tree species (Cinnamomum camphora). The leaf water potential, chlorophyll content, proline content and plasma membrane permeability for two species seedlings were measured in different soil drought conditions. The results showed that, on the 9th day of drought stress, the leaf water potential of two species decreased obviously, whereas the free proline content and plasma membrane permeability increased sharply. On the 11th day, the leaf water potential of C. camphora seedlings was lower than that of M. yunnanensis seedlings; the plasma membrane permeability in C. camphora seedling leaves increased much more than that in M. yunnanensis seedling leaves, which showed that the injury to the former by soil drought stress was more severe than that to the latter. The free proline content in M. yunnanensis seedling leaves continued to increase on the 11th day, but that in the C. camphora seedling leaves started to drop obviously, indicating that the reduction of osmotic regulation substance in C. camphora seedling leaves after the 11th day was unable to maintain the osmotic balance between the plasma system and its surroundings and the water loss occurred inevitably. Comprehensively, M. yunnanensis seedlings enhanced the drought-resistance in the course of soil drought stress by maintaining higher leaf water potential and by increasing osmotic regulation substance to promote cell plasma concentration and maintain membrane structure integrity so as to reduce water loss. The subordination function index evaluated with fuzzy mathematic theory also showed that the drought-resistant capacity ofM. yunnanensis seedlings was stronger than that of C. camphora seedlings.

  8. Tree fern trunks facilitate seedling regeneration in a productive lowland temperate rain forest.

    Science.gov (United States)

    Gaxiola, Aurora; Burrows, Larry E; Coomes, David A

    2008-03-01

    Seedling regeneration on forest floors is often impaired by competition with established plants. In some lowland temperate rain forests, tree fern trunks provide safe sites on which tree species establish, and grow large enough to take root in the ground and persist. Here we explore the competitive and facilitative effects of two tree fern species, Cyathea smithii and Dicksonia squarrosa, on the epiphytic regeneration of tree species in nutrient-rich alluvial forests in New Zealand. The difficulties that seedlings have in establishing on vertical tree fern trunks were indicated by the following observations. First, seedling abundance was greatest on the oldest sections of tree fern trunks, near the base, suggesting that trunks gradually recruited more and more seedlings over time, but many sections of trunk were devoid of seedlings, indicating the difficulty of establishment on a vertical surface. Second, most seedlings were from small-seeded species, presumably because smaller seeds can easily lodge on tree fern trunks. Deer browsing damage was observed on 73% of epiphytic seedlings growing within 2 m of the ground, whereas few seedlings above that height were browsed. This suggests that tree ferns provide refugia from introduced deer, and may slow the decline in population size of deer-preferred species. We reasoned that tree ferns would compete with epiphytic seedlings for light, because below the tree fern canopy photosynthetically active radiation (PAR) was about 1% of above-canopy PAR. Frond removal almost tripled %PAR on the forest floor, leading to a significant increase in the height growth rate (HGR) of seedlings planted on the forest floor, but having no effects on the HGRs of epiphytic seedlings. Our study shows evidence of direct facilitative interactions by tree ferns during seedling establishment in plant communities associated with nutrient-rich soils.

  9. Growth Responses of Acacia mangium and Paraserianthes falcataria Seedlings on Different Soil Origin under Nursery Condition

    Directory of Open Access Journals (Sweden)

    Tirtha Ayu Paramitha

    2015-12-01

    Full Text Available The objective of the present study was to examine the growth responses of Acacia mangium (mangium and Paraserianthes falcataria (sengon seedlings growing on different soil origin under nursery condition. This study was started in September 2012 and terminated in March 2013.  The seedlings were grown from seeds sown in a plastic box filled with sterilized sands. One week after sowing, the seedlings were transplanted into polybags contained sterilized soils originated from secondary forest, Imperata cylindrica grassland and ex-coal mining. The number of all seedlings were 180 seedlings consisted of 3 different soils, 2 species of seedlings with 10 seedlings replicated 3 times. Assessment was conducted one week after transplanting, then subsequently monitored every 2 weeks, except dry weighing and counting nodules were performed at the end of the study. A completely randomized design was used in this study. The data was analyzed using Costat software. The study resulted that the different of soil origin influenced on all growth variables of mangium and sengon of 4.5 months old. The survival rate of seedlings, height and diameter increments, dry weight and root nodules were better in both species of seedlings growing on soil originated from secondary forest and Imperata grassland compared with the soil from ex-coal mining. But the survival rates of sengon seedlings were higher than that of mangium on these three soils. The highest dry weight of sengon seedlings was achieved on soil originated from secondary forest. In the present study, soil originated from secondary forest increased more in weight of shoot than root, so that the shoot-root ratio was unbalanced more than one. Based on the results of this study, it is recommended that soil from secondary forest and Imperata grassland can be used as growing media for mangium and sengon seedlings in the nursery.

  10. Book review: The Tallgrass Prairie Center guide to seed and seedling identification in the Upper Midwest

    Science.gov (United States)

    Larson, Diane L.; Galatowitsch, Susan M.

    2011-01-01

    This attractive, slim volume provides a wonderful introduction to a neglected aspect of prairie plant identification: seeds and seedlings. Williams, and the illustrator Brent Butler, take the mystery out of dichotomous keys with clear descriptions, vivid illustrations, and abundant photographs of characteristics that distinguish common, tallgrass prairie, seedlings. A botanical novice should have no problem using this book to identify seedlings in their prairie garden – presuming that they planted only those species included in the book (more on that later).

  11. The growth and uptake of Ga and In of rice (Oryza sative L.) seedlings as affected by Ga and In concentrations in hydroponic cultures.

    Science.gov (United States)

    Syu, Chien-Hui; Chien, Po-Hsuan; Huang, Chia-Chen; Jiang, Pei-Yu; Juang, Kai-Wei; Lee, Dar-Yuan

    2017-01-01

    Limited information is available on the effects of gallium (Ga) and indium (In) on the growth of paddy rice. The Ga and In are emerging contaminants and widely used in high-tech industries nowadays. Understanding the toxicity and accumulation of Ga and In by rice plants is important for reducing the effect on rice production and exposure risk to human by rice consumption. Therefore, this study investigates the effect of Ga and In on the growth of rice seedlings and examines the accumulation and distribution of those elements in plant tissues. Hydroponic cultures were conducted in phytotron glasshouse with controlled temperature and relative humidity conditions, and the rice seedlings were treated with different levels of Ga and In in the nutrient solutions. The growth index and the concentrations of Ga and In in roots and shoots of rice seedlings were measured after harvesting. A significant increase in growth index with increasing Ga concentrations in culture solutions (<10mgGaL(-1)) was observed. In addition, the uptake of N, K, Mg, Ca, Mn by rice plants was also enhanced by Ga. However, the growth inhibition were observed while the In concentrations higher than 0.08mgL(-1), and the nutrients accumulated in rice plants were also significant decreased after In treatments. Based on the dose-response curve, we observed that the EC10 (effective concentration resulting in 10% growth inhibition) value for In treatment was 0.17mgL(-1). The results of plant analysis indicated that the roots were the dominant sink of Ga and In in rice seedlings, and it was also found that the capability of translocation of Ga from roots to shoots were higher than In. In addition, it was also found that the PT10 (threshold concentration of phytotoxicity resulting in 10% growth retardation) values based on shoot height and total biomass for In were 15.4 and 10.6μgplant(-1), respectively. The beneficial effects on the plant growth of rice seedlings were found by the addition of Ga in

  12. Identification and Seedlings Growth Evaluation of Shorea Species-Producing Tengkawang

    Directory of Open Access Journals (Sweden)

    Eritrina Windyarini

    2015-06-01

    Full Text Available Most of  non timber forest product (NTFP utilization taken from natural forests which decrease on productivity annually, including tengkawang producer species which taken from West Kalimantan natural forests. This condition needs an effort to preserve those species from natural population utilization through plantation forest development that require spesific strategy. This study was part of breeding strategy of shorea species producing tengkawang which aimed to species identify and seedling growth evaluation used genetic material from 2 (two population from West Kalimantan. The research was arranged in 2 (two steps, i.e.1 species identification used morphology characteristic difference, and 2 seedling growth evaluation (height,diameter,sturdiness. Seedling growth evaluation was arranged in RCBD, with 5 plot (combination of species and source population, contained 25 seedlings and 4 replications (blocks. The result showed that seedlings of shorea species producing tengkawang, i.e. S.stenoptera,  S.macrophylla, and S.gysbertsiana can be different from its stipulae morphology characteristic. Growth of 10 months shorea species producing tengkawang seedlings were significantly different on height and sturdiness. Seedlings height were 67,19 – 88,79 cm, seedlings diameter 9,65 – 10,33 mm and sturdiness 7 – 9,21 in range. The best seedling growth was S.stenoptera and S.macrophylla from Gunung Bunga, West Kalimantan.

  13. Identification and Seedlings Growth Evaluation of Shorea Species-Producing Tengkawang

    Directory of Open Access Journals (Sweden)

    Eritrina Windyarini

    2015-06-01

    Full Text Available Most of non timber forest product (NTFP utilization taken from natural forests which decrease on productivity annually, including tengkawang producer species which taken from West Kalimantan natural forests. This condition needs an effort to preserve those species from natural population utilization through plantation forest development that require spesific strategy. This study was part of breeding strategy of shorea species producing tengkawang which aimed to species identify and seedling growth evaluation used genetic material from 2 (two population from West Kalimantan. The research was arranged in 2 (two steps, i.e.1 species identification used morphology characteristic difference, and 2 seedling growth evaluation (height,diameter,sturdiness. Seedling growth evaluation was arranged in RCBD, with 5 plot (combination of species and source population, contained 25 seedlings and 4 replications (blocks. The result showed that seedlings of shorea species producing tengkawang, i.e. S.stenoptera, S.macrophylla, and S.gysbertsiana can be different from its stipulae morphology characteristic. Growth of 10 months shorea species producing tengkawang seedlings were significantly different on height and sturdiness. Seedlings height were 67,19 – 88,79 cm, seedlings diameter 9,65 – 10,33 mm and sturdiness 7 – 9,21 in range. The best seedling growth was S.stenoptera and S.macrophylla from Gunung Bunga, West Kalimantan.

  14. Effects of filamentous macroalgae mats on growth and survival of eelgrass, Zostera marina, seedlings

    DEFF Research Database (Denmark)

    Rasmussen, Jonas; Olesen, Birgit; Krause-Jensen, Dorte

    2012-01-01

    A laboratory experiment was conducted to assess the effect of filamentous algae mats on the performance of seedlings of the eelgrass, Zostera marina. The seedlings were covered by three levels (3, 6 and 9 cm) of natural (Chaetomorpha linum) and imitation algae mats and it was hypothesized...... that the effects of the natural algae on seedling growth may be more severe because of the metabolic demands of the algae. Results show that coverage by both C. linum and imitation algae significantly reduced seedling growth and increased allocation of resources to above ground tissues. No clear effects of algae...

  15. [Effects of grafting on physiological characteristics of melon (Cucumis melo) seedlings under copper stress].

    Science.gov (United States)

    Tan, Ming-min; Zhang, Xin-ying; Fu, Qiu-shi; He, Zhong-qun; Wang, Huai-song

    2014-12-01

    The effects of grafting on physiological characters of melon (Cucumis melo) seedlings under copper stress were investigated with Pumpkin Jingxinzhen No. 3 as stock and oriental melon IVF09 as scion. The results showed that the physiological characters of melon seedlings were inhibited significantly under copper stress. Compared with self-rooted seedlings, the biomass, the contents of photosynthetic pigment, glucose and fructose, the photosynthetic parameters, the activities of sucrose phosphate synthase, neutral invertase and acid invertase in the leaves of the grafted seedlings were increased significantly. The uptake of nutrients was improved with the contents of K, P, Na increased and the content of Cu decreased. When the concentration of Cu2+ stress was 800 micromol L(-1), the contents of Cu in the leaves and roots of the grafted seedlings were decreased by 31.3% and 15.2%, respectively. Endogenous hormone balance of seedlings was improved by grafting. In the grafted seedlings, the content of IAA and peroxidase activity were higher, whereas the contents of ABA, maleicdialdehyde, the activities of superoxide dismutase and catalase were lower than that in the control. It was concluded that the copper stress on the physiological characters of melon seedlings was relieved by grafting which improved the resistance of the grafted seedlings.

  16. Effects of Exogenous Cinnamic Acids on the Growth and Physiological Characteristics of Cucumber Seedlings

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    In order to study the effects of exogenous cinnamic acids on plant growth, contents of photosynthetic pigment, root activities and ATPase activities of root membrane at cucumber seedling stage, the seedlings of Shandong Mici cucumber were tested. The results showed that seedlings growth, contents of photosynthetic pigment, root activities and ATPase activities of root membrane were inhibited by cinnamic acids. The growth and root activities of seedlings were significantly cinnamic acids, whereas ATPase activities exhibited a higher sensitivity and greatly decreased in the soil amended with 50 mg kg-1 cinnamic acids. These results suggested that cinnamic acids could induce a stress condition, and the stress intensities increased with enhanced cinnamic acid concentration.

  17. Research and Development of Statistical Analysis Software System of Maize Seedling Experiment

    Directory of Open Access Journals (Sweden)

    Hui Cao

    2014-03-01

    Full Text Available In this study, software engineer measures were used to develop a set of software system for maize seedling experiments statistics and analysis works. During development works, B/S structure software design method was used and a set of statistics indicators for maize seedling evaluation were established. The experiments results indicated that this set of software system could finish quality statistics and analysis for maize seedling very well. The development of this software system explored a new method for screening of maize seedlings.

  18. Variation in chromosome number in the seedling progeny of a somaclone of Paspalum dilatatum

    Institute of Scientific and Technical Information of China (English)

    ZHUJM; LJDAVIES; 等

    1994-01-01

    The somaclone,C39,derived by tissue culture from the obligate apomict Paspalum dilatatum cv Raki(2n=50),had 50 chromosomes and a karyotype apparently identical to Raki.SC2 seedlings of C39 showed a high degree of phenotypic variation which was often associated with increased chromosome numbers,but some of the variant seedlings were karyotypically indistinguishable from Raki or C39.Plants with increased chromosome numbers exhibited a high degree of intraplant chromosome variation(aneusomaty).In one of the SC2 seedlings,the chromosome number of root tip cells varied from 58 to 82 and in several other seedlings the range was more than 10.The results suggested that the ability to form seed apomictically was much reduced in C39 and that this plant showed some capacity for sexual reproduction and the resulting seedlings,with a chromosome number of about 70,were genetically unstable.Of 11 SC2 seedlings examined cytologically,6 did not produce any viable seed.Seedlings grown from seed of the remaining 5 plants showed that aneusomaty persisted in the SC3 generation.SC3 seedlings which were phenotypically similar to their maternal parent showed a similar range of chromosome numbers to that parent.Some of the SC3 seedlings exhibited an even wider range of chromosome numbers(e.g.56-136),and these plants were all dwarfs.

  19. Improving seedling growth in longleaf pine plantations with nematicidal soil fumigants.

    Science.gov (United States)

    Ruehle, J L

    1969-07-01

    In-row, preplanting fumigation with DD and DBCP in a longleaf pine plantation was evaluated for nematode control, improved seedling survival, and early and uniform release of seedlings from the grass stage. Only DD significantly lowered the nematode population during the first growing season. DBCP not only failed to control nematodes, but was phytotoxic. Fumigation had little effect on seedling survival. Seedlings in rows fumigated with DD started height growth earlier and produced taller trees after 5 years than those in nonfumigated rows.

  20. Influence of slow disintegrating fertilizer rates on quality of gazania (Gazania rigens L. seedlings

    Directory of Open Access Journals (Sweden)

    Vujošević Ana

    2007-01-01

    Full Text Available The work has examined the influence of slow disintegrating fertilizer rates of Scotts (Osmocote Exact formulation 15:9:9:MgO + Me on quality of Gazania rigens L. seedlings. The seedlings of Gazania rigens L. was produced in polystyrene containers (speedling system and polypropylene pots (pot system. During the production of seedlings the fertilizer has been applied in rates (0, 1, 2, 3, and 4g/l. The results show that the fertilizer rate of substrata 4g/l influences the qualitative properties of Gazania rigens L. seedlings.

  1. SOURCES OF MYCORRHIZAL INFECTION OF SHOREA ACUMINATA SEEDLINGS UNDER LABORATORY CONDITIONS

    Directory of Open Access Journals (Sweden)

    LEE Su SEE

    1995-01-01

    Full Text Available Uninoculated dipterocarp seedlings raised in normal field soil in nurseries were always found to have mycorrhizas after a few months. This study set out to determine whether dipterocarp seedlings could continue to grow and develop in the absence of mycorrhizas and also to determine possible sources of mycorrhizal infection of dipterocarp seedlings raised under laboratory conditions using Shorea acuminata as a typical example. Seedlings were planted in capped or uncapped perspex boxes containing sterile or non-sterile field soil and watered daily with sterile water or tap water. Seedling growth and development of mycorrhizas were monitored at monthly intervals for up to seven months. Seedlings grown in sterile soil remained uninfected after seven months while infection was found in some of the seedlings grown in normal soil regardless of whether they had been watered with tap water or sterile water. This showed that field soil (i.e. under grass far from the forest contained suitable inoculum for forest tree seedlings. Tap water and the air were not important sources of infection. However, mycorrhizal infection was very uneven indicating that the inoculum was probably very unevenly distributed in the soil or that the inoculum density was rather low. Seedlings grown in sterile soil showed better growth than those grown in normal soil and infection of roots by parasitic fungi in the latter was also observed.

  2. Age Limits.

    Science.gov (United States)

    Antfolk, Jan

    2017-03-01

    Whereas women of all ages prefer slightly older sexual partners, men-regardless of their age-have a preference for women in their 20s. Earlier research has suggested that this difference between the sexes' age preferences is resolved according to women's preferences. This research has not, however, sufficiently considered that the age range of considered partners might change over the life span. Here we investigated the age limits (youngest and oldest) of considered and actual sex partners in a population-based sample of 2,655 adults (aged 18-50 years). Over the investigated age span, women reported a narrower age range than men and women tended to prefer slightly older men. We also show that men's age range widens as they get older: While they continue to consider sex with young women, men also consider sex with women their own age or older. Contrary to earlier suggestions, men's sexual activity thus reflects also their own age range, although their potential interest in younger women is not likely converted into sexual activity. Compared to homosexual men, bisexual and heterosexual men were more unlikely to convert young preferences into actual behavior, supporting female-choice theory.

  3. Foliar potassium nitrate application improves the tolerance of Citrus macrophylla L. seedlings to drought conditions.

    Science.gov (United States)

    Gimeno, V; Díaz-López, L; Simón-Grao, S; Martínez, V; Martínez-Nicolás, J J; García-Sánchez, F

    2014-10-01

    Scarcity of water is a severe limitation in citrus tree productivity. There are few studies that consider how to manage nitrogen (N) nutrition in crops suffering water deficit. A pot experiment under controlled-environment chambers was conducted to explore if additional N supply via foliar application could improve the drought tolerance of Citrus macrophylla L. seedlings under dry conditions. Two-month-old seedlings were subjected to a completely random design with two water treatments (drought stress and 100% water/field capacity). Plants under drought stress (DS) received three different N supplies via foliar application (DS: 0, DS + NH4NO3: 2% NH4NO3, DS + KNO3: 2% KNO3). KNO3-spraying increased leaf and stem DW as compared with DS + NH4NO3 and DS treatments. Leaf water potential (Ψw) was decreased by drought stress in all the treatments. However, in plants from DS + NH4NO and DS + KNO3, this was due to a decrease in the leaf osmotic potential, whereas the decrease in those from the DS treatment was due to a decrease in the leaf turgor potential. These responses were correlated with the leaf proline and K concentrations. DS + KNO3-treated plants had a higher leaf proline and K concentration than DS-treated plants. In terms of leaf gas exchange parameters, it was observed that net assimilation of CO2 [Formula: see text] was decreased by drought stress, but this reduction was much lower in DS + KNO3-treated plants. Thus, when all results are taken into account, it can be concluded that a 2% foliar-KNO3 application can enhance the tolerance of citrus plants to water stress by increasing the osmotic adjustment process. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  4. Mobilization of seed storage lipid by Arabidopsis seedlings is retarded in the presence of exogenous sugars

    Directory of Open Access Journals (Sweden)

    Gibson Susan I

    2002-05-01

    Full Text Available Abstract Background Soluble sugar levels must be closely regulated in germinating seeds to ensure an adequate supply of energy and building materials for the developing seedling. Studies on germinating cereal seeds indicate that production of sugars from starch is inhibited by increasing sugar levels. Although numerous studies have focused on the regulation of starch metabolism, very few studies have addressed the control of storage lipid metabolism by germinating oilseeds. Results Mobilization of storage lipid by germinating seeds of the model oilseed plant Arabidopsis thaliana (L. Heynh. occurs at a greatly reduced rate in the presence of exogenous glucose or mannose, but not in the presence of equi-molar 3-O-methylglucose or sorbitol. The sugar-insensitive5-1/abscisic acid-insensitive4-101 (sis5-1/abi4-101 mutant is resistant to glucose inhibition of seed storage lipid mobilization. Wild-type seedlings become insensitive to glucose inhibition of storage lipid breakdown within 3 days of the start of imbibition. Conclusions Growth in the presence of exogenous glucose significantly retards mobilization of seed storage lipid in germinating seeds from wild-type Arabidopsis. This effect is not solely due to the osmotic potential of the media, as substantially higher concentrations of sorbitol than of glucose are required to exert significant effects on lipid breakdown. The inhibitory effect of glucose on lipid breakdown is limited to a narrow developmental window, suggesting that completion of some critical metabolic transition results in loss of sensitivity to the inhibitory effect of glucose on lipid breakdown.

  5. Dry forest restoration and unassisted native tree seedling recruitment at Auwahi, Maui

    Science.gov (United States)

    Medeiros, Arthur C.; von Allmen, E. I.; Chimera, C.G.

    2014-01-01

    Efforts to restore highly degraded but biologically significant forests draw from a limited toolbox. With less than 10% of their former distribution remaining, Hawaiian dry forests, though critically endangered, remain important biological and cultural refugia. At restoration onset (1997), vegetation of restoration and control areas of degraded Auwahi dry forest, Maui Island, was similar, dominated by nonnative graminoids (restoration 78.3%; control 75.4%), especially Cenchrus (Pennisetum) clandestinus. In 2012, unrestored control area vegetation was basically unchanged. In contrast, in the restoration area in 2012, native shrub cover increased from 3.1% to 81.9%, and cover of nonnative graminoids declined from 75.4% to 3.3%. In 2012, nonplanted seedlings of 14 of 22 native tree species and six of seven native shrub species were observed in restoration plots; the majority (99%) were five native (Dodonaea viscosa, Coprosma foliosa, Osteomeles anthyllidifolia, Chamaesyce celastoides, Nestegis sandwicensis) and one nonnative species (Bocconia frutescens). By 2012, stem counts of native woody plants had increased from 12.4 to 135.0/100 m2, and native species diversity increased from 2.4 to 6.6/100 m2. By 2012, seven rare dry forest tree species, Charpentiera obovata, Nothocestrum latifolium, Ochrosia haleakalae, Pleomele auwahiensis, Santalum ellipticum, S. haleakalae, and Streblus pendulinus, had established seedlings and/or saplings within the restoration site, especially notable because natural reproduction is largely lacking elsewhere. Without development and implementation of appropriate management strategies, remaining Hawaiian dry forest will likely disappear within the next century. Multicomponent restoration incorporating ungulate exclusion, weed control, and outplanting as described here offers one strategy to conserve and restore tracts of high-value but degraded forests.

  6. Influence of the24-epibrassinolide on tolerance to salt stress in rice seedlings

    Directory of Open Access Journals (Sweden)

    Cristina Ferreira Larré

    2014-02-01

    Full Text Available Salinity can be considered a limiting factor to the growth and development of plants to affect various physiological processes. The aim of this study was to determine the effect of 24 – epibrassinolide in emergence, seedling growth, leaf area and chlorophyll concentration in two cultivars of rice in salt stress condition. The study was conducted at the research laboratory of seeds and greenhouse of the Department of Botany UFPel. Rice seeds of cvs. BRS Bojurú tolerant to salinity and BRS Querência not tolerant, were soaked for two hours in water, 100 mMNaCl and 100 mMNaCl solutions supplemented with 24 – epibrassinolide at concentrations of 0.01, 0,1 and 1.0 mM and sown in expanded polypropylene tray. The experimental design was completely randomized with five treatments, two cultivars and four replications. Means were compared by Tukey test (p < 5 %, within each cultivar. In cv. BRS Querência the application of 24 – epibrassinolide increased chlorophyll concentration, leaf area, seedling length and dry mass of shoots, reducing the effects caused by salinity. However, cv. BRS Bojurú, tolerant to salinity, the application of the 24 – epibrassinolide 0.01 mM did not affect the growth characteristics, but the concentrations of 0.1 and 1.0 mM reduced the same, no affecting the concentration of chlorophyll. The 24 – epibrassinolide in cv. BRS Querencia, induces an increase in all growth characteristics, minimizing the deleterious effects of salinity on the sensitive cultivar. In cv. BRS Bojurú, higher concentrations reduce the growth characteristics, not by changing the concentration of chlorophyll.

  7. Analysis of peg formation in cucumber seedlings grown on clinostats and in a microgravity (space) environment

    Science.gov (United States)

    Link, B. M.; Cosgrove, D. J.

    1999-01-01

    In young cucumber seedlings, the peg is a polar out-growth of tissue that functions by snagging the seed coat, thereby freeing the cotyledons. Previous studies have indicated that peg formation is gravity dependent. In this study we analyzed peg formation in cucumber seedlings (Cucumis sativus L. cv Burpee Hybrid II) grown under conditions of normal gravity, microgravity, and simulated microgravity (clinostat rotation). Seeds were germinated on the ground, in clinostats and on board the space shuttle (STS 95) for 1-2 days, frozen and subsequently examined for their stage of development, degree of hook formation, number of pegs formed, and peg morphology. The frequency of peg formation in space grown seedlings was found to be nearly identical to that of clinostat grown seedlings and to differ from that of seedlings germinated under normal gravity only in a minority of cases; approximately 6% of the seedlings formed two pegs and nearly 2% of the seedlings lacked pegs, whereas such abnormalities did not occur in ground controls. The degree of hook formation was found to be less pronounced for space grown seedlings, compared to clinostat grown seedlings, indicating a greater degree of decoupling between peg formation and hook formation in space. Nonetheless, in all seedlings having single pegs and a hook, the peg was found to be positioned correctly on the inside of the hook, showing that there is coordinate development even in microgravity environments. Peg morphologies were altered in space grown samples, with the pegs having a blunt appearance and many pegs showing alterations in expansion, with the peg extending out over the edges of the seed coat and downwards. These phenotypes were not observed in clinostat or ground grown seedlings.

  8. Fuel reduction at a Spanish heathland by prescribed fire and mechanical shredding: effects on seedling emergence.

    Science.gov (United States)

    Fernández, Cristina; Vega, José A; Fonturbel, Teresa

    2013-11-15

    Traditional heathland burning has declined in Spain, leading to fuel accumulation and fuel reduction treatments have become common for severe wildfire hazard reduction. These methods need to maintain the botanical composition of those shrub communities. Prescribed fire has been widely used in the past, but we need to compare mechanical fuel reduction with prescribed fire because it is easier and safer to carry out in a wide range of weather conditions. This information could be particularly useful in flammable ecosystems all over the world where traditional anthropogenic burning has declined. In this study, we compared the effects of prescribed burning and mechanical shredding on the seedling emergence and its relation to the mature vegetation in a fire-prone heathland dominated by Erica australis L. and Pterospartum tridentatum (L.) Willk., in Galicia (NW Spain). We combined a greenhouse experiment with periodic field inventories of seedling emergence. In the greenhouse study, the seedling emergence was significantly higher in the soil samples after burning (383 seedlings m(-2)) than in samples before burning (242 seedlings m(-2)). In contrast, there was no significant difference in seedling density before and after mechanical shredding (243 compared with 261 seedlings m(-2)). Also, the number of seedlings that emerged after burning was significantly higher than that emerged after mechanical shredding. The maximum temperatures at the soil organic layer surface during burning were significantly and positively related to the density of Halimium lasianthum ssp. alyssoides and P. tridentatum seedlings. In the field study, the observed seedling density was very low both after prescribed burning and mechanical shredding. There was a high degree of similarity between emerged seedlings and mature vegetation in both the treated and in the untreated soils, which was probably a consequence of the dominance of resprouting species. Some consequences for the management of

  9. Characteristics of cadmium uptake and membrane transport in roots of intact wheat (Triticum aestivum L.) seedlings.

    Science.gov (United States)

    Li, Lian-Zhen; Tu, Chen; Peijnenburg, Willie J G M; Luo, Yong-Ming

    2017-02-01

    Wheat is one of several cereals that is capable of accumulating higher amounts of Cd in plant tissues. It is important to understand the Cd(2+) transport processes in roots that result in excess Cd accumulation. Traditional destructive technologies have limited capabilities in analyzing root samples due to methodological limitations, and sometimes may result in false conclusions. The mechanisms of Cd(2+) uptake into the roots of wheat seedlings (Triticum aestivum L.) were investigated by assessing the impact of various inhibitors and channel blockers on Cd accumulation as well as the real-time net Cd(2+) flux at roots with the non-destructive scanning ion-selective electrode technique. The P-type ATPase inhibitor Na3VO4 (500 μM) had little effect on Cd uptake (p wheat, suggesting that Cd(2+) uptake into wheat root cells is not directly dependent on H(+) gradients. While, the uncoupler 2,4-dinitrophenol significantly limited Cd(2+) uptake (p wheat, suggesting the existence of metabolic mediation in the Cd(2+) uptake process by wheat. The Cd content at the whole-plant level in wheat was significantly (p wheat root via Ca(2+) channels. In addition, our results suggested a role for protein synthesis in mediating Cd(2+) uptake and transport by wheat. Copyright © 2016. Published by Elsevier Ltd.

  10. Competition for nitrogen between Fagus sylvatica and Acer pseudoplatanus seedlings depends on soil nitrogen availability

    Directory of Open Access Journals (Sweden)

    Xiuyuan eLi

    2015-04-01

    Full Text Available Competition for nitrogen (N, particularly in resource-limited habitats, might be avoided by different N acquisition strategies of plants. In our study, we investigated whether slow-growing European beech and fast-growing sycamore maple seedlings avoid competition for growth-limiting N by different N uptake patterns and the potential alteration by soil N availability in a microcosm experiment. We quantified growth and biomass indices, 15N uptake capacity and N pools in the fine roots. Overall, growth indices, N acquisition and N pools in the fine roots were influenced by species-specific competition depending on soil N availability. With interspecific competition, growth of sycamore maple reduced regardless of soil N supply, whereas beech only showed reduced growth when N was limited. Both species responded to interspecific competition by alteration of N pools in the fine roots; however, sycamore maple showed a stronger response compared to beech for almost all N pools in roots, except for structural N at low soil N availability. Beech generally preferred organic N acquisition while sycamore maple took up more inorganic N. Furthermore, with interspecific competition, beech had an enhanced organic N uptake capacity, while in sycamore maple inorganic N uptake capacity was impaired by the presence of beech. Although sycamore maple could tolerate the suboptimal conditions at the cost of reduced growth, our study indicates its reduced competitive ability for N compared to beech.

  11. Drought-Induced Leaf Proteome Changes in Switchgrass Seedlings

    Directory of Open Access Journals (Sweden)

    Zhujia Ye

    2016-08-01

    Full Text Available Switchgrass (Panicum virgatum is a perennial crop producing deep roots and thus highly tolerant to soil water deficit conditions. However, seedling establishment in the field is very susceptible to prolonged and periodic drought stress. In this study, a “sandwich” system simulating a gradual water deletion process was developed. Switchgrass seedlings were subjected to a 20-day gradual drought treatment process when soil water tension was increased to 0.05 MPa (moderate drought stress and leaf physiological properties had expressed significant alteration. Drought-induced changes in leaf proteomes were identified using the isobaric tags for relative and absolute quantitation (iTRAQ labeling method followed by nano-scale liquid chromatography mass spectrometry (nano-LC-MS/MS analysis. Additionally, total leaf proteins were processed using a combinatorial library of peptide ligands to enrich for lower abundance proteins. Both total proteins and those enriched samples were analyzed to increase the coverage of the quantitative proteomics analysis. A total of 7006 leaf proteins were identified, and 257 (4% of the leaf proteome expressed a significant difference (p < 0.05, fold change <0.6 or >1.7 from the non-treated control to drought-treated conditions. These proteins are involved in the regulation of transcription and translation, cell division, cell wall modification, phyto-hormone metabolism and signaling transduction pathways, and metabolic pathways of carbohydrates, amino acids, and fatty acids. A scheme of abscisic acid (ABA-biosynthesis and ABA responsive signal transduction pathway was reconstructed using these drought-induced significant proteins, showing systemic regulation at protein level to deploy the respective mechanism. Results from this study, in addition to revealing molecular responses to drought stress, provide a large number of proteins (candidate genes that can be employed to improve switchgrass seedling growth and

  12. Drought-Induced Leaf Proteome Changes in Switchgrass Seedlings.

    Science.gov (United States)

    Ye, Zhujia; Sangireddy, Sasikiran; Okekeogbu, Ikenna; Zhou, Suping; Yu, Chih-Li; Hui, Dafeng; Howe, Kevin J; Fish, Tara; Thannhauser, Theodore W

    2016-01-01

    Switchgrass (Panicum virgatum) is a perennial crop producing deep roots and thus highly tolerant to soil water deficit conditions. However, seedling establishment in the field is very susceptible to prolonged and periodic drought stress. In this study, a "sandwich" system simulating a gradual water deletion process was developed. Switchgrass seedlings were subjected to a 20-day gradual drought treatment process when soil water tension was increased to 0.05 MPa (moderate drought stress) and leaf physiological properties had expressed significant alteration. Drought-induced changes in leaf proteomes were identified using the isobaric tags for relative and absolute quantitation (iTRAQ) labeling method followed by nano-scale liquid chromatography mass spectrometry (nano-LC-MS/MS) analysis. Additionally, total leaf proteins were processed using a combinatorial library of peptide ligands to enrich for lower abundance proteins. Both total proteins and those enriched samples were analyzed to increase the coverage of the quantitative proteomics analysis. A total of 7006 leaf proteins were identified, and 257 (4% of the leaf proteome) expressed a significant difference (p 1.7) from the non-treated control to drought-treated conditions. These proteins are involved in the regulation of transcription and translation, cell division, cell wall modification, phyto-hormone metabolism and signaling transduction pathways, and metabolic pathways of carbohydrates, amino acids, and fatty acids. A scheme of abscisic acid (ABA)-biosynthesis and ABA responsive signal transduction pathway was reconstructed using these drought-induced significant proteins, showing systemic regulation at protein level to deploy the respective mechanism. Results from this study, in addition to revealing molecular responses to drought stress, provide a large number of proteins (candidate genes) that can be employed to improve switchgrass seedling growth and establishment under soil drought conditions (Data are

  13. Soil Temperature Dependent Growth of Cotton Seedlings Before Emergence

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Soil temperature is an important variable governing plant growth and development.Studies were conducted under laboratory conditions to determine the effect of soil temperature on root and shoot growth of cotton during emergence.Cotton seedlings were grown for 192 h at 20,32 and 38℃ in soil packed in 300 mm long and 50 mm diameter cylinders.The data indicated that the longest roots(173 ram)as well as shoots(152 mm)were recorded at 32 ℃ followed by 20 (130 mm root and 82 mm shoot)and 38℃(86 mm root and 50 mm shoot).Roots grown at 20 and 38 ℃ were 20% and 50% shorter,respectively,than those grown at 32℃ after 192 h.Roots and shoots exhibited the lowest length and dry biomass at 38℃.Shoot lengths grown at 20(74 ram)and 38℃(51 mm)were 44% and 61% shorter than those grown at 32℃(131 mm)after 180 h growth period,respectively.Growth at all three temperatures followed a similar pattern.Initially there was a linear growth phase followed by the reduction or cessation of growth.Time to cessation of growth varied with temperature and decreased faster at higher temperatures.Sowing of cotton should be accomlplished before seedbed reaches a soil temperature(≥38℃)detrimental for emergence.Further,the seedbeds should be capable of providing sufficient moisture and essential nutrients for emerging seedling before its seed reserves are exhausted to enhance seedling establishment in soil.

  14. Improving Acacia auriculiformis seedlings using microbial inoculant (Beneficial Microorganisms)

    Institute of Scientific and Technical Information of China (English)

    Bayezid M. Khan; M.K. Hossain; M.A.U. Mridha

    2014-01-01

    A microbial inoculant, known as effective microorganisms (EM), was applied to determine its efficacy on seed germination and seedling growth in the nursery of Acacia auriculiformis A Cunn. ex Benth. The seedlings were grown in a mixture of sandy soil and cow dung (3:1) and kept in polybags;EM was poured at different concentra-tions (0.1%, 0.5%, 1%, 2%, 5% and 10%). Seed germination rate and growth parameters of seedlings - shoot and root lengths, fresh and dry weights of shoots and roots, vigor, volume, and quality indices and stur-diness - were measured. The nodulation status influenced by EM was also observed, along with the measurement of pigment contents in leaves. The highest germination rate (72%) was observed in 2% EM solution while the lowest (55%) was found in control treatment. The highest shoot and root lengths (30.6 cm and 31.2 cm respectively) were recorded in 2%EM and were significantly (p <0.05) different from control. Both fresh and dry weights of shoots were maximum (8.66 g and 2.99 g respectively) in 2% EM, whereas both fresh and dry weights of root were maximum (2.56 g and 1.23 g respectively) in 5%EM solution. Although the highest vigor index, volume index, and sturdiness (4450, 628 and 67.5 respec-tively) were found in 2% EM, the highest quality index (0.455) was found in 5%EM solution. The nodule number was higher at a very low (0.5%) concentration of EM but it normally decreased with the increase of concentration. The contents of chlorophyll a, chlorophyll b, and caro-tenoid were maximum (43.26 mg⋅L-1, 13.56 mg⋅L-1and 17.99 mg⋅L-1 respectively) in 2%EM. Therefore, low concentration of EM (up to 2%)can be recommended for getting maximum seed germination and seed-ling development of A. auriculiformis in the nursery.

  15. EFFECTS OF PISOLITHUS TINCTORIUS AND LACCARIA FRATERNA ON THE GROWTH AND MYCORRfflZAL DEVELOPMENT OF PINUSPATULA SEEDLINGS

    Directory of Open Access Journals (Sweden)

    M. SUDHAKARA REDDY

    1995-01-01

    Full Text Available Vegetative inoculum of Pisolithus tinctorius and Laccariafraterna were inoculated to Pinuspatula seedlings grown in both steam sterilized and unsterilized shola soil. After 4 months of seedling growth, 10 seedlings from each treatment were harvested and various growth parameters were studied. Inoculation of these two fungi resulted in the production of ectomycorrhizas and increase in growth of P. patula seedlings when compared to uninoculated seedlings. Laccariafraterna inoculated seedlings showed more number of mycorrhizas than P. tinctorius inoculated seedlings at the end of one year. Both these fungi poorly colonized the root system in both soil treatments. There was no significant difference between these two fungi in improving the seedling growth in the nursery.

  16. Effect of Ionic and Chelate Assisted Hexavalent Chromium on Mung Bean Seedlings (Vigna radiata L. wilczek. var k-851 During Seedling Growth

    Directory of Open Access Journals (Sweden)

    Mohanty, Monalisa

    2013-04-01

    Full Text Available The effect of Cr+6 with and without chelating agents were assessed in mung bean seedlings grown hydroponically. It was noted that the growth parameters showed a declining trend with increasing Cr+6 concentrations without chelate application. Among the seedlings grown with chelated chromium complexes, Cr+6–DTPA (10µM showed highest growth rate of roots as well as shoots. At higher concentration of Chromium i.e. Cr+6 (100µM, there exhibited high chlorophyll content in mung bean leaves where the seedlings showed stunted growth. The seedlings treated without and with chelated chromium complexes showed increased proline content as compared to control. The enzymatic study showed that, the catalase activity was maximum in shoots as compared to roots and the reverse is true in the case of peroxidase activity i.e. the roots showed higher value than that of the shoots.

  17. CROWN GALL INCIDENCE: SEEDLING PARADOX WALNUT ROOTSTOCK VERSUS OWN-ROOTED ENGLISH WALNUT TREES

    Science.gov (United States)

    Seedling Paradox (Juglans hindsii x J. regia) has been the rootstock of choice for English walnut in California because of its vigor and greater tolerance of wet soil conditions. However, seedling Paradox rootstock is highly susceptible to crown gall, a disease caused by the soil-borne bacterium Agr...

  18. A systems genetics study of seed quality and seedling vigour in Brassica rapa

    NARCIS (Netherlands)

    Basnet, R.K.

    2015-01-01

    Summary Seed is the basic and most critical input for seed propagated agricultural crops: seed quality and seedling vigour determine plant establishment, growth and development in both natural and agricultural ecosystems. Seed quality and seedling vigour are mainly determined by the

  19. [Relationships between seed size and seedling growth strategy of herbaceous plant: a review].

    Science.gov (United States)

    Wu, Gao-lin; Du, Guo-zhen

    2008-01-01

    Seed size and seedling recruitment strategy are of importance in the life-history strategy of plant. In this paper, the current ecological researches at home and aboard on the relationships between seed size and seedling growth were reviewed from the aspects of the effects of seed size on seed germination and seedling emergence, the relationships between seed size and seedling growth traits, and the relationships between seed size and seedling survival and competition ability. Some suggestions on future researches in this field were put forward. There were likely different relationships between seed size and seedling growth in different microenvironments and vegetation types, and the effects of seed size on seedling growth could result in different contributions of different seed-size species to the seedling recruitment of vegetation. The large-scale community level and the small-scale intra- and inter-species level researches on this issue should be strengthened, which would have significance for the recruitment and renewing of natural vegetation.

  20. Development of a doorframe-typed swinging seedling pick-up device for automatic field transplantation

    Energy Technology Data Exchange (ETDEWEB)

    Han, H.; Mao, H.; Hu, J.; Tian, K.

    2015-07-01

    A doorframe-typed swing seedling pick-up device for automatic field transplanters was developed and evaluated in a laboratory. The device, consisting of a path manipulator and two grippers, can move the pins slowly to extract seedlings from the tray cells and return quickly to the pick-up point for the next extraction. The path manipulator was constructed with the creative design of type-Ⅱ mechanism combination in series. It consists of an oscillating guide linkage mechanism and a grooved globoidal cam mechanism. The gripper is a pincette-type mechanism using the pick-up pins to penetrate into the root mass for seedling extraction. The dynamic analysis of the designed seedling pick-up device was simulated with ADAMS software. Being the first prototype, various performance tests under local production conditions were conducted to find out the optimal machine operation parameters and transplant production conditions. As the gripper with multiple fine pins was moved by the swing pick-up device, it can effectively complete the transplanting work cycle of extracting, transferring, and discharging a seedling. The laboratory evaluation showed that the pick-up device equipped with two grippers can extract 80 seedlings/min with a 90% success and a 3% failure in discharging seedlings, using 42-day-old tomato plantlets. The quality of extracting seedlings was satisfactory. (Author)

  1. Response of germinating barley seeds to Fusarium graminearum: The first molecular insight into Fusarium seedling blight

    DEFF Research Database (Denmark)

    Yang, Fen; Svensson, Birte; Finnie, Christine

    2011-01-01

    Fusarium seedling blight in cereals can result in significant reductions in plant establishment but has not received much attention. The disease often starts during seed germination due to sowing of the seeds infected by Fusarium spp. including Fusarium graminearum. In order to gain the first...... provides the first molecular insight into Fusarium seedling blight....

  2. Growth of transplanted timber species seedlings in the south of the Colombian Amazon: A preliminary study

    NARCIS (Netherlands)

    Gruezmacher, M.; Duivenvoorden, J.F.

    2008-01-01

    Two commonly used timber species in the area of Amacayacu National Park (Quararibea sp. and Minquartia guianensis) were selected to develop an experiment that compared the early performance of seedlings in mature and old secondary forest. We transplanted seedlings of these species into mature and

  3. Seedling regeneration on decayed pine logs after the deforestation events caused by pine wilt disease

    Directory of Open Access Journals (Sweden)

    Y. Fukasawa

    2016-12-01

    Full Text Available Coarse woody debris (CWD forms an important habitat suitable for tree seedling establishment, and the CWD decay process influences tree seedling community. In Japan, a severe dieback of Pinus densiflora Sieb. & Zucc. caused by pine wilt disease (PWD damaged huge areas of pine stands but creates huge mass of pine CWD. It is important to know the factors influencing seedling colonization on pine CWD and their variations among geographical gradient in Japan to expect forest regeneration in post-PWD stands. I conducted field surveys on the effects of latitude, climates, light condition, decay type of pine logs, and log diameter on tree seedling colonization at ten geographically distinct sites in Japan. In total, 59 tree taxa were recorded as seedlings on pine logs. Among them, 13 species were recorded from more than five sites as adult trees or seedlings and were used for the analyses. A generalized linear model showed that seedling colonization of Pinus densiflora was negatively associated with brown rot in sapwood, while that of Rhus trichocarpa was positively associated with brown rot in heartwood. Regeneration of Ilex macropoda had no relationships with wood decay type but negatively associated with latitude and MAT, while positively with log diameter. These results suggested that wood decay type is a strong determinant of seedling establishment for certain tree species, even at a wide geographical scale; however, the effect is tree species specific.

  4. Fertility-dependent effects of ectomycorrhizal fungal communities on white spruce seedling nutrition

    Science.gov (United States)

    Alistair J. H. Smith; Lynette R. Potvin; Erik A. Lilleskov

    2015-01-01

    Ectomycorrhizal fungi (EcMF) typically colonize nursery seedlings, but nutritional and growth effects of these communities are only partly understood. To examine these effects, Picea glauca seedlings collected from a tree nursery naturally colonized by three dominant EcMF were divided between fertilized and unfertilized treatments. After one...

  5. Development of a doorframe-typed swinging seedling pick-up device for automatic field transplantation

    Directory of Open Access Journals (Sweden)

    Han Luhua

    2015-06-01

    Full Text Available A doorframe-typed swing seedling pick-up device for automatic field transplanters was developed and evaluated in a laboratory. The device, consisting of a path manipulator and two grippers, can move the pins slowly to extract seedlings from the tray cells and return quickly to the pick-up point for the next extraction. The path manipulator was constructed with the creative design of type-II mechanism combination in series. It consists of an oscillating guide linkage mechanism and a grooved globoidal cam mechanism. The gripper is a pincette-type mechanism using the pick-up pins to penetrate into the root mass for seedling extraction. The dynamic analysis of the designed seedling pick-up device was simulated with ADAMS software. Being the first prototype, various performance tests under local production conditions were conducted to find out the optimal machine operation parameters and transplant production conditions. As the gripper with multiple fine pins was moved by the swing pick-up device, it can effectively complete the transplanting work cycle of extracting, transferring, and discharging a seedling. The laboratory evaluation showed that the pick-up device equipped with two grippers can extract 80 seedlings/min with a 90% success and a 3% failure in discharging seedlings, using 42-day-old tomato plantlets. The quality of extracting seedlings was satisfactory.

  6. An improved method for seed-bank analysis : Seedling emergence after removing the soil by sieving

    NARCIS (Netherlands)

    ter Heerdt, G.N.J.; Bekker, R.M.; Bakker, J.P.; Verweij, G.L.

    1. The seedling emergence method for assessing the size of the seed bank is improved by washing soil samples on a fine sieve and spreading the thus concentrated samples in a 3-5 mm thick layer on sterilized potting compost. 2. The method largely increases the number of seedlings that emerge as

  7. Energy biomass tree seedling production study. Fuels from woody biomass. Progress report, September 1978-January 1980

    Energy Technology Data Exchange (ETDEWEB)

    Foote, K.R.

    1980-03-01

    The research to date has centered around the establishment of baseline growing conditions for a number of species of tree seedlings, primarily deciduous hardwoods. As these baseline conditions were established for each specie, the shoot and root environments were manipulated in an attempt to establish techniques to increase seedling growth and reduce production times. Seedlings were outplanted in an attempt to establish baseline survival rates for seedlings grown in totally controlled environments. Studies to determine the optimum container for tree seedling production have been run and will continue as other containers are identified and made available. The most significant of the research results has been in the maximization of seedling growth. Seedling production times have been decreased in some species by as much as 50% under the baseline production times. Controlled environment production techniques provide for plant densities as high as 144 seedlings per square foot of growing space. Investigations of growing media indicate a significant species specific responses. Preliminary results of outplanting indicate survival rates as high as 90% plus.

  8. An improved method for seed-bank analysis : Seedling emergence after removing the soil by sieving

    NARCIS (Netherlands)

    ter Heerdt, G.N.J.; Bekker, R.M.; Bakker, J.P.; Verweij, G.L.

    1996-01-01

    1. The seedling emergence method for assessing the size of the seed bank is improved by washing soil samples on a fine sieve and spreading the thus concentrated samples in a 3-5 mm thick layer on sterilized potting compost. 2. The method largely increases the number of seedlings that emerge as compa

  9. Two-year results of herbicide released, naturally-regenerated bottomland cherrybark and shumard oak seedlings

    Science.gov (United States)

    John F., Jr. Thompson; Larry E. Nix

    1995-01-01

    After clearcuting in bottomlands, oak seedlings that naturally regenerate are often overtopped by woody pioneer species, sprouts and herbaceous material. To improve the competitive status of three- to four-year-old oak seedlings in two bottomland stands in South Carolina, several herbicides and methods of application were used to kill and/or stunt the overtopping...

  10. The changes of glutation reductase activity in maize seedlings under heavy metals and herbicide frontjere influence

    Directory of Open Access Journals (Sweden)

    V. S. Bilchuk

    2005-01-01

    Full Text Available In modelling experiment joint action of heavy metal ions (lead, cadmium and cloroacetanilide herbicide frontjere on glutationreductase activity in maize seedlings at initial stages of ontogenesis was investigated. The increasing of enzyme activity in a sprouting grain at herbicide and ions of lead and cadmium presence and variation of enzyme activity in seedlings were established at joint action of toxicants.

  11. Seedling establishment and physiological responses to temporal and spatial soil moisture changes

    Science.gov (United States)

    Jeremy Pinto; John D. Marshall; Kas Dumroese; Anthony S. Davis; Douglas R. Cobos

    2016-01-01

    In many forests of the world, the summer season (temporal element) brings drought conditions causing low soil moisture in the upper soil profile (spatial element) - a potentially large barrier to seedling establishment. We evaluated the relationship between initial seedling root depth, temporal and spatial changes in soil moisture during drought after...

  12. Effect of nitrogen fertilization and seedling density on fine rice yield in Faisalabad, Pakistan

    Directory of Open Access Journals (Sweden)

    Ehsanullah, Khawar Jabran, Ghulam Asghar

    2012-11-01

    Full Text Available Rice seedlings density per hill and optimal nitrogen fertilization exercises a strong influence on rice growth and grain yield due to competitive effects both on the vegetative and reproductive development. Present study was conducted to explore the possible role of nitrogen fertilizer and seedlings density on rice kernel yield and yield contributing factors. Three nitrogen (N rates viz. 75, 100 and 125 kg ha-1 and four seedling densities (1, 2, 3 and 4 seedlings hill-1 were tested in the study. Panicle length, number of branches per panicle and kernels per panicle remained unaffected at varying levels of N and rice seedlings per hill. Two, 3 and 4 seedlings per hill along with 100 and 125 kg N ha-1 resulted in maximum rice kernel yield and harvest index due to enhanced number of panicle bearing tillers and 1000-kernel weight. While application of N at 75 kg ha-1 along with one seedling per hill revealed the poorest results with respect to 1000-kernel weight, panicle bearing tillers per hill and the kernel yield of rice. In crux, two seedlings hill-1 at 100 kg N ha-1 proved to be the best combination for maximizing the rice yield in the Faisalabad area of Pakistan.

  13. Development and plasticity of endangered shrub Lindera melissifolia (Lauraceae) seedlings under contrasting light regimes

    Science.gov (United States)

    Brian R Lockhart; Emile S Gardiner; Theran Stautz; Theodor D. Leininger

    2012-01-01

    Lindera melissifolia (Walt.) Blume seedlings were raised in a growth chamber to determine the effects of light availability on shoot growth pattern, and basic leaf and stem growth. Lindera melissifolia seedlings exhibited a sympodial shoot growth pattern for 3 months following emergence from the soil medium, but this pattern was characterized by a reduction in leaf...

  14. Morphotypes of Dactylorhiza incarnata (L. Soу (Orchidaceae seedlings in vitro

    Directory of Open Access Journals (Sweden)

    Oleg A. Marakaev

    2012-03-01

    Full Text Available The morphotypes, linear parameters and morphological features for Dactylorhiza incarnata seedlings in vitro have been set. The uneven growth and development of seedlings in depending from the location and degree of contact with the medium have been identified.

  15. Chilling Tolerance and Physiological Parameters as Influenced by Grafting in Watermelon Seedlings

    Institute of Scientific and Technical Information of China (English)

    LIU Hui-ying; ZHU Zhu-jun; LU Guo-hua; QIAN Qiong-qiu

    2003-01-01

    The influences of different rootstocks on chilling tolerance and physiological parameters in wa-termelon seedlings have been studied. The results showed that grafting improved the chilling tolerance. Com-pared with own-rooted watermelon seedlings, the grafted watermelon seedlings had lower chilling injury index,lower electrolytic leakage (%), lower malondialdehyde (MDA) content, higher chlorophyll and proline con-tent, and higher activities of superoxide dismutase (SOD), ascorbate peroxidase (AsA-POD) and de-hydroascorbate reductase (DR) in the leaves under iow temperature stress. There was a considerable differenceof chilling tolerance among different grafted watermelon seedlings due to the difference of rootstock chillingtolerance. After low temperature treatment, the grafted seedling with higher chilling tolerance had lower elec-trolytic leakage ( %), lower MDA content, higher proline content and higher activities of SOD, AsA-POD andDR in the leaves compared with the grafted seedling with weaker chilling tolerance. From these, we could con-clude that chilling tolerance of watermelon seedlings may be related to higher antioxidative ability and mem-brane stability in the plants. The chilling tolerance of grafted seedling could be properly evaluated by compre-hensive physiological indexes but not a single physiological index.

  16. Pseudomonas fluorescens and Pseudomonas putida for Promoting Growth of Jatropha curcas Seedling Root

    Directory of Open Access Journals (Sweden)

    Sri Sumarsih

    2012-05-01

    Full Text Available Pseudomonas fluorescens and P. putida are Plant Growth Promoting Rhizobacteria (PGPR that can produce growth hormone. The objective of this study is to know the effects of those two combined species of PGPR on seedling root growth of Jatropha curcas. The condition of the seedling root determines the success of dry land cultivation. The root which has wider coverage, is larger in number, and is bigger in diameter makes seedling more resistant to stress in dry land environment. In the experiment, two kinds of plant materials are used for seedling, the Jatropha seed and stem material, which are treated in a mixed culture of PGPR. For the Jatropha seed, this mixed culture of PGPR is given at the same time of cultivating the sprout on the seedling medium. For the stem cutting, the PGPR is poured in together during the first watering of the seedling cultivation medium. In the fourthweek, the observed growth parameters are root length, root diameter, primary and secondary lateral root numbers, Root Length Density (RLD, Frequency of Lateral Root (FLR, and Specific Root Length (SRL. These data are analyzed using analysis of variant with DMRT test at 0.05 level of significance. The result of this study shows that PGPR tend to reduce FLR values on the seedling root made from seeds. On the seedling root made from stem cutting, PGPR increase the root length, primary and secondary lateral root numbers, root diameter, FLR and SRL values as well.

  17. Maize white seedling 3 results from disruption of homogentisate solanesyl transferase

    Science.gov (United States)

    Maize white seedling 3 (w3) has served as a model albino-seedling mutant since its discovery in 1923. We show here that the w3 phenotype is caused by disruptions in homogentisate solanesyl transferase (HST), an enzyme that catalyzes the committed step in plastoquinone-9 (PQ9) biosynthesis. This re...

  18. Effects of Different Quantities of Tea-leaf Wormcast Substrate on the Growth of Tomato Seedling

    Directory of Open Access Journals (Sweden)

    YANG Wei

    2015-08-01

    Full Text Available The tomato seedling experiment was conducted to investigate the effect of substrate on the tomato seedling growth from five proportions of tea-leaf wormcast to peat, perlite and vermiculite, namely treatment I(1:5:2:2, treatment Ⅱ(2:4:2:2, treatment Ⅲ(3:3:2:2, treatment Ⅳ(4:2:2:2, treatment Ⅴ(6:0:2:2, respectively. The botany properties and characters of tomato seedling were observed to discuss the application effect of tea-leaf wormcast substrate. The results showed that in all treatments of the compound substrate of tea-leaf wormcast, except of treatment I, the tomato seedling indexes were superior to the control treatments(conventional seedling substrate in market, and the treatments Ⅳ had the best effect, followed by treatment Ⅴ. With the increasing proportion of tea-leaf wormcast, the plant height, stem diameter, SPAD value, and root morphology index of tomato seedlings firstly increased, and then decreased obviously. The substrate with the appropriate proportion of tea-leaf wormcast could obviously improve the quality of tomato seedlings, and the treatment Ⅳ was the best, which could be recommended for the actual production of tomato seedling.

  19. Recovery of l-year-old loblolly pine seedlings from simulated browse damage

    Science.gov (United States)

    Michael G. Shelton; Michael D. Cain

    2002-01-01

    Loblolly pine (Pinus taeda L.) seedlings are frequently browsed by a wide variety of animals during the first few years of their development. Although anecdotal observations indicate that the potential for seedling recovery is good, there is little quantitative information on the factors affecting the recovery process. Thus, we conducted a study to...

  20. Tree invasion in a semi-arid savanna in Zimbabwe : seedling recruitment of Acacia karroo

    NARCIS (Netherlands)

    Chirara, C. (Chipangura)

    2002-01-01

    In this thesis Chirara reports on his study on the competitive interaction between savanna grasses and young tree seedlings of Acacia karroo, from hereon indicated as ' Acacia seedlings' . Acacia is one of the tree species that dominates savanna grassland in situations of overgrazing (bush encroachm

  1. Tree invasion in a semi-arid savanna in Zimbabwe : seedling recruitment of Acacia karroo

    NARCIS (Netherlands)

    Chirara, C. (Chipangura)

    2001-01-01

    In this thesis Chirara reports on his study on the competitive interaction between savanna grasses and young tree seedlings of Acacia karroo, from hereon indicated as ' Acacia seedlings' . Acacia is one of the tree species that dominates savanna grassland in situations of overgrazing (bush

  2. Seedling regeneration on decayed pine logs after the deforestation events caused by pine wilt disease

    Directory of Open Access Journals (Sweden)

    Y. Fukasawa

    2016-12-01

    Full Text Available Coarse woody debris (CWD forms an important habitat suitable for tree seedling establishment, and the CWD decay process influences tree seedling community. In Japan, a severe dieback of Pinus densiflora Sieb. & Zucc. caused by pine wilt disease (PWD damaged huge areas of pine stands but creates huge mass of pine CWD. It is important to know the factors influencing seedling colonization on pine CWD and their variations among geographical gradient in Japan to expect forest regeneration in post-PWD stands. I conducted field surveys on the effects of latitude, climates, light condition, decay type of pine logs, and log diameter on tree seedling colonization at ten geographically distinct sites in Japan. In total, 59 tree taxa were recorded as seedlings on pine logs. Among them, 13 species were recorded from more than five sites as adult trees or seedlings and were used for the analyses. A generalized linear model showed that seedling colonization of Pinus densiflora was negatively associated with brown rot in sapwood, while that of Rhus trichocarpa was positively associated with brown rot in heartwood. Regeneration of Ilex macropoda had no relationships with wood decay type but negatively associated with latitude and MAT, while positively with log diameter. These results suggested that wood decay type is a strong determinant of seedling establishment for certain tree species, even at a wide geographical scale; however, the effect is tree species specific.

  3. Fungicide seed treatments for evaluating the corn seedling disease complex following a winter rye cover crop

    Science.gov (United States)

    Seed treatments have been used to manage corn seedling diseases since the 1970’s and they contain a combination of active ingredients with specificity towards different pathogens. We hypothesized that using different seed treatment combinations and assessing seedling disease incidence and severity ...

  4. Effect of apical meristem clipping on carbon allocation and morphological development of white oak seedlings

    Science.gov (United States)

    Paul P. Kormanik; Shi-Jean S. Sung; T.L. Kormanik; Stanley J. Zarnoch

    1994-01-01

    Seedlings from three open-pollinated half-sib white oak seedlots were clipped in mid-July and their development was compared to nonclipped controls after one growing season.In general when data were analyzed by family, clipped seedlings were significantly less desirable in three to six of the eight variables tested.Numerically, in all families seedlots, the clipped...

  5. Inhibition of seedling survival under Rhodendron maximum (Ericaceae): could allelopathy be a cause?

    Science.gov (United States)

    Erik T. Nilsen; John F. Walker; Orson K. Miller; Shawn W. Semones; Thomas T. Lei; Barton D. Clinton

    1999-01-01

    In the Southern Appalachian Mountains a subcanopy species, Rhododendron maximum, inhibits the establishment and survival of canopy tree seedlings. One of the mechanisms by which seedlings could be inhibited is an allelopathic effect of decomposing litter or leachate from the canopy of R. maximum (R.m.) on seed germination, root...

  6. Variation among black walnut seedling families in resistance to competition and allelopathy

    Science.gov (United States)

    George Rink; J.W. Van Sambeek

    1985-01-01

    Of three environmental variables affecting black walnut seedling establishment, moisture stress overshadowed the effects of fescue leachate and fertilizer. Interactions between moisture stress and family and between fescue leachate and moisture stress for both seedling height and dry weight suggested that selection for tolerance to moisture stress is possible, whereas...

  7. Formula for Determining Number of Basic Seedlings at Scattered-Planting with Seedling Dry-Raised on Plastic Trays in Double-Season Rice

    Institute of Scientific and Technical Information of China (English)

    PAN Xiao-hua; CHEN Xiao-rong; YANG Fu-sun

    2006-01-01

    The tiller emergence in seedling nursery beds and field, and panicle formation in the field were investigated under scattered-planting with seedling dry-raised on plastic trays in double-season rice. A significant difference was noted in the non-synchronously-emerged tillers (the tillers that formed from latent buds and did not emerge following the normal tillering law on seedling nursery beds and recovered to grow after scattered-planting or transplanting) as well as the percentage of the available synchronously-emerged tillers between seedlings raised on plastic trays under dry-land conditions (DPT) and seedlings raised on nursery beds under wetland conditions (WB). The seedlings under DPT had some non-synchronously-emerged tillers, but those under WB had not. Therefore, the traditional formula for determining the number of rice seedlings was improved, and the formula for determining the number of basic seedlings under scattered planting with DPT in double-season rice was introduced. For early rice, it was X=YI{(1+t1r1)[1+(N-n-SN)Rr2]+(SN-3-t1)R2r5}, and for late rice, it was X=YI{(1+t1r1)[1+(N-n-SN)Rr2]+(N-n-SN-3)Rr2R1r3+(SN-3-t1)R2r5}. Where, X represents reasonable number of basic seedlings per unit area at scattered-planting; Y,number of fitting panicles per unit area; t1, total number of tillers per plant; r1, percentage of the total available tillers; N, total number of leaves of the main culm; n, total number of elongated internodes in the main culm; SN, seedling leaf ages at scattered-planting; R,percentage of the primary tillers emerged in available node-position; r2, percentage of the available primary tillers; R1, percentage of the secondary tillers in the field (except the secondary tillers of the seedlings); r3, percentage of the available secondary tillers; R2,percentage of the asynchronously-emerged tillers after scattered-planting; r5, percentage of the available non-synchronously-emerged tillers after scattered-planting.

  8. Spectral Indices Accurately Quantify Changes in Seedling Physiology Following Fire: Towards Mechanistic Assessments of Post-Fire Carbon Cycling

    Directory of Open Access Journals (Sweden)

    Aaron M. Sparks

    2016-07-01

    Full Text Available Fire activity, in terms of intensity, frequency, and total area burned, is expected to increase with a changing climate. A challenge for landscape-level assessment of fire effects, often termed burn severity, is that current remote sensing assessments provide very little information regarding tree/vegetation physiological performance and recovery, limiting our understanding of fire effects on ecosystem services such as carbon storage/cycling. In this paper, we evaluated whether spectral indices common in vegetation stress and burn severity assessments could accurately quantify post-fire physiological performance (indicated by net photosynthesis and crown scorch of two seedling species, Larix occidentalis and Pinus contorta. Seedlings were subjected to increasing fire radiative energy density (FRED doses through a series of controlled laboratory surface fires. Mortality, physiology, and spectral reflectance were assessed for a month following the fires, and then again at one year post-fire. The differenced Normalized Difference Vegetation Index (dNDVI spectral index outperformed other spectral indices used for vegetation stress and burn severity characterization in regard to leaf net photosynthesis quantification, indicating that landscape-level quantification of tree physiology may be possible. Additionally, the survival of the majority of seedlings in the low and moderate FRED doses indicates that fire-induced mortality is more complex than the currently accepted binary scenario, where trees survive with no impacts below a certain temperature and duration threshold, and mortality occurs above the threshold.

  9. Effects of filamentous macroalgae on growth and survival of eelgrass, Zostera marina, seedlings

    DEFF Research Database (Denmark)

    Rasmussen, Jonas; Krause-Jensen, Dorte; Olesen, Birgit

    the mat and periods of anoxia in the lower parts can possibly be followed by release of sulphide from the sediments. We assessed the impact of algae mats on seedling performance and evaluated the relative importance of light attenuation and low oxygen concentrations for seedling growth and survival based...... and effects on seedling growth can thus be attributed to reduced light caused by shading of the algae. Generally, the seedlings are shown to be robust to short-term reductions in light availability, but further experiments are needed to elucidate the relative contributions of reduced light vs. anoxic...... on eelgrass seedling performance. The covering of eelgrass shoots by algae decreases the light availability and may hamper the diffusive movement of oxygen, inorganic carbon and nutrients to and from the shoots. Moreover, the high productivity of the algae can result in large diurnal oxygen variations within...

  10. Increased Biomass of Nursery-Grown Douglas-Fir Seedlings upon Inoculation with Diazotrophic Endophytic Consortia

    Directory of Open Access Journals (Sweden)

    Zareen Khan

    2015-10-01

    Full Text Available Douglas-fir (Pseudotsuga menziesii seedlings are periodically challenged by biotic and abiotic stresses. The ability of endophytes to colonize the interior of plants could confer benefits to host plants that may play an important role in plant adaptation to environmental changes. In this greenhouse study, nursery-grown Douglas-fir seedlings were inoculated with diazotrophic endophytes previously isolated from poplar and willow trees and grown for fifteen months in nutrient-poor conditions. Inoculated seedlings had significant increases in biomass (48%, root length (13% and shoot height (16% compared to the control seedlings. Characterization of these endophytes for symbiotic traits in addition to nitrogen fixation revealed that they can also solubilize phosphate and produce siderophores. Colonization was observed through fluorescent microscopy in seedlings inoculated with gfp- and mkate-tagged strains. Inoculation with beneficial endophytes could prove to be valuable for increasing the production of planting stocks in forest nurseries.

  11. Metabolite profiling of Ricinus communis germination at different temperatures provides new insights into thermo-mediatedrequirements for successful seedling establishment

    NARCIS (Netherlands)

    Ribeiro de Jesus, P.R.; Willems, L.A.J.; Mutimawurugo, M.C.; Fernandez, L.G.; Castro, De R.D.; Ligterink, W.; Hilhorst, H.W.M.

    2015-01-01

    Ricinus communis seeds germinate to a high percentage and faster at 35¿C than at lower temperatures, butwith compromised seedling establishment. However, seedlings are able to cope with high temperaturesat later stages of seedling establishment if germination occurred at lower temperatures. Our

  12. [Allelopathy of different plants on wheat, cucumber and radish seedlings].

    Science.gov (United States)

    Shen, Huimin; Guo, Hongru; Huang, Gaobao

    2005-04-01

    By means of bioassay in laboratory and field, this paper studied the allelopathy of 18 kinds of plants in Gansu Province on the seedlings of wheat, cucumber and radish. The results showed that the aqueous extract of the stems and leaves of Artemisia annua, Solanum nigrum and Datura stramonium had the strongest allelopathy on test receptor plants, and their synthetic inhibitory effect (SE) was 47.66%, 32.89% and 26.63%, respectively. The SE of Xanthium sibiricum, Portulaca oleraca, Cephalanoplos segetum, and Chenopodium album was 21.71%, 20.93%, 20.83% and 20.2%, respectively, while Vicia amoena (SE 3.5%), Setaria viridis (SE 2.2%), and Cymamchum chinense (SE 1.97%) had a weaker allelopathy. Chenopodium ambrosioides (SE - 1.03%), Polygonum caespitosum (SE - 1.63%) and Avena fatua (SE 5.33%) had no evident allelopathy, but Artemisia annua affected the seedling height and fresh weight of radish, cucumber, wheat and maize, with the SE being 54.07%, 38.46%, 33.35% and 20.88%, respectively. Artemisia annua had a 44.70% of SE on wheat growth, and thus, had a certain value to develop and use.

  13. Effects of topsoil removal on seedling emergence and species diversity

    Energy Technology Data Exchange (ETDEWEB)

    Winkel, V.K.; Ostler, W.K.

    1994-02-01

    Approximately 800 hectares on the US Department of Energy Nevada Test Site and vicinity are contaminated with Plutonium. As part of a cleanup effort, both the vegetation and the top 5--10 cm of soil may be removed. A study was developed to determine the effects of topsoil removal on seedling emergence and plant species diversity. Trial plots were prepared by removing 5, 10, or 20 cm of topsoil, seeding a mix of nine native species, mulching with straw, and then anchoring the straw with erosion netting. Additional plots (0 topsoil removal treatment) were lightly bladed to remove existing vegetation and then treated as above. Approximately 85 mm of supplemental irrigation was applied to help initiate germination during early spring. Seedling density data of seeded and nonseeded species was collected following emergence, and species diversity was calculated with the Shannon diversity index for the nonseeded species. Densities of seeded species either were unaffected by or increased with increased depth of topsoil removal. In general, densities of nonseeded species decreased with increased depth of topsoil removal. The number of species, species diversity and evenness also decreased with increased depth of topsoil removal. Initial emergence of seeded species is apparently unaffected by topsoil removal at this site.

  14. Developmental reaction norms for water stressed seedlings of succulent cacti.

    Science.gov (United States)

    Rosas, Ulises; Zhou, Royce W; Castillo, Guillermo; Collazo-Ortega, Margarita

    2012-01-01

    Succulent cacti are remarkable plants with capabilities to withstand long periods of drought. However, their adult success is contingent on the early seedling stages, when plants are highly susceptible to the environment. To better understand their early coping strategies in a challenging environment, two developmental aspects (anatomy and morphology) in Polaskia chichipe and Echinocactus platyacanthus were studied in the context of developmental reaction norms under drought conditions. The morphology was evaluated using landmark based morphometrics and Principal Component Analysis, which gave three main trends of the variation in each species. The anatomy was quantified as number and area of xylem vessels. The quantitative relationship between morphology and anatomy in early stages of development, as a response to drought was revealed in these two species. Qualitatively, collapsible cells and collapsible parenchyma tissue were observed in seedlings of both species, more often in those subjected to water stress. These tissues were located inside the epidermis, resembling a web of collapsible-cell groups surrounding turgid cells, vascular bundles, and spanned across the pith. Occasionally the groups formed a continuum stretching from the epidermis towards the vasculature. Integrating the morphology and the anatomy in a developmental context as a response to environmental conditions provides a better understanding of the organism's dynamics, adaptation, and plasticity.

  15. Developmental reaction norms for water stressed seedlings of succulent cacti.

    Directory of Open Access Journals (Sweden)

    Ulises Rosas

    Full Text Available Succulent cacti are remarkable plants with capabilities to withstand long periods of drought. However, their adult success is contingent on the early seedling stages, when plants are highly susceptible to the environment. To better understand their early coping strategies in a challenging environment, two developmental aspects (anatomy and morphology in Polaskia chichipe and Echinocactus platyacanthus were studied in the context of developmental reaction norms under drought conditions. The morphology was evaluated using landmark based morphometrics and Principal Component Analysis, which gave three main trends of the variation in each species. The anatomy was quantified as number and area of xylem vessels. The quantitative relationship between morphology and anatomy in early stages of development, as a response to drought was revealed in these two species. Qualitatively, collapsible cells and collapsible parenchyma tissue were observed in seedlings of both species, more often in those subjected to water stress. These tissues were located inside the epidermis, resembling a web of collapsible-cell groups surrounding turgid cells, vascular bundles, and spanned across the pith. Occasionally the groups formed a continuum stretching from the epidermis towards the vasculature. Integrating the morphology and the anatomy in a developmental context as a response to environmental conditions provides a better understanding of the organism's dynamics, adaptation, and plasticity.

  16. Arsenic toxicity in soybean seedlings and their attenuation mechanisms.

    Science.gov (United States)

    Armendariz, Ana L; Talano, Melina A; Travaglia, Claudia; Reinoso, Herminda; Wevar Oller, Ana L; Agostini, Elizabeth

    2016-01-01

    Even though vast areas contaminated with arsenic (As) are under soybean (Glycine max) cultivation, little is known about the growth and intrinsic antioxidant metabolism of soybean in response to As exposure. Thus, an evaluation was carried out of plant growth, root anatomy, antioxidant system and photosynthetic pigment content under arsenate (As(V)) and arsenite (As(III)) treatment. Soybean seedling growth was significantly affected at 25 μM or higher concentrations of As(V) or As(III), and the toxic effect on root growth was associated with cell death of root tips. Microscopic analysis of cross-sections of As-treated root showed a reduction in the cortex area, dark deposits in cortex cells and broken cells in the outer layer. Similarly, in the vascular cylinder, dark deposits within xylem vessel elements and phloem cell walls were observed. In all the analyzed parameters, the deleterious effect was more evident under As(III) than As(V) treatment. Arsenic-treated soybean seedlings showed increased activity of antioxidant enzymes [total peroxidases (Px) and superoxide dismutase (SOD)] in root and shoot harvested after 2 and 5 d of treatment. However, a reduction in chlorophyll content and an increase in membrane lipids peroxidation were observed. It is suggested that root structural alterations induced by As, such as the particular pattern of dark depositions in the vascular system, could be associated with an adaptation or detoxification mechanism to prevent As translocation to the aboveground tissues.

  17. Mexican propolis flavonoids affect photosynthesis and seedling growth.

    Science.gov (United States)

    King-Díaz, Beatriz; Granados-Pineda, Jessica; Bah, Mustapha; Rivero-Cruz, J Fausto; Lotina-Hennsen, Blas

    2015-10-01

    As a continuous effort to find new natural products with potential herbicide activity, flavonoids acacetin (1), chrysin (2) and 4',7-dimethylnarangenin (3) were isolated from a propolis sample collected in the rural area of Mexico City and their effects on the photosynthesis light reactions and on the growth of Lolium perenne, Echinochloa crus-galli and Physalis ixocarpa seedlings were investigated. Acacetin (1) acted as an uncoupler by enhancing the electron transport under basal and phosphorylating conditions and the Mg(2+)-ATPase. Chrysin (2) at low concentrations behaved as an uncoupler and at concentrations up to 100 μM its behavior was as a Hill reaction inhibitor. Finally, 4',7-dimethylnarangenin (3) in a concentration-dependent manner behaved as a Hill reaction inhibitor. Flavonoids 2 and 3 inhibited the uncoupled photosystem II reaction measured from water to 2,5-dichloro-1,4-benzoquinone (DCBQ), and they did not inhibit the uncoupled partial reactions measured from water to sodium silicomolybdate (SiMo) and from diphenylcarbazide (DPC) to diclorophenol indophenol (DCPIP). These results indicated that chrysin and 4',7-dimethylnarangenin inhibited the acceptor side of PS II. The results were corroborated with fluorescence of chlorophyll a measurements. Flavonoids also showed activity on the growth of seedlings of Lolium perenne and Echinochloa crus-galli. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Physiological Responses of Cotton at Seedling Stage to Waterlogged Stress

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    Kai-wen Liu

    2012-12-01

    Full Text Available In Jianghan plain as well as south China, cotton at seedling stage often encounter waterlogged stress, by which normal growth of cotton plants is affected, the purpose of the study is to analyze the responses to Waterlogging stress. Therefore flooding experiments of cotton in the seedling stage was made and a series of physiological indices were observed such as Chlorophyll Relative value (RC, chlorophyll fluorescence (F0, Fm, Malondialdehyde (MDA, nomadic Proline (Pro, Dissoluble Sugar (DS, Peroxidase (POD and Superoxide Dismutase (SOD, Analytic results indicated that, after Waterlogging, chlorophyll hydrolysis rate was higher in the first 3 days, the peak value of chlorophyll fluorescence decrease occurred between the 6th to 9th day. It figured that stagnant water on the field should be drained off in 3 days after Waterlogging stress, to avoid the photosynthetic efficiency being strongly inhibited. The balance of normal physiological metabolic process in cotton leaf was broken after Waterlogging, some new negative changes occurred, as MDA content increasing and the activity of SOD decline. Some other positive changes were accompanied, as the increasing of DS and Pro content and the activity of POD, for protecting active tissues. These physiological indices appeared regularly changing characterized by fastslow- fast, which can be simulated in unary cubic regression curve model.

  19. Cadmium interferes with maintenance of auxin homeostasis in Arabidopsis seedlings.

    Science.gov (United States)

    Hu, Yan Feng; Zhou, Guoying; Na, Xiao Fan; Yang, Lijing; Nan, Wen Bin; Liu, Xu; Zhang, Yong Qiang; Li, Jiao Long; Bi, Yu Rong

    2013-07-15

    Auxin and its homeostasis play key roles in many aspects of plant growth and development. Cadmium (Cd) is a phytotoxic heavy metal and its inhibitory effects on plant growth and development have been extensively studied. However, the underlying molecular mechanism of the effects of Cd stress on auxin homeostasis is still unclear. In the present study, we found that the root elongation, shoot weight, hypocotyl length and chlorophyll content in wild-type (WT) Arabidopsis seedlings were significantly reduced after exposure to Cd stress. However, the lateral root (LR) formation was markedly promoted by Cd stress. The level and distribution of auxin were both greatly altered in primary root tips and cotyledons of Cd-treated plants. The results also showed that after Cd treatment, the IAA content was significantly decreased, which was accompanied by increases in the activity of the IAA oxidase and alteration in the expression of several putative auxin biosynthetic and catabolic genes. Application of the auxin transport inhibitor, 1-naphthylphthalamic acid (NPA) and 1-naphthoxyacetic acid (1-NOA), reversed the effects of Cd on LR formation. Additionally, there was less promotion of LR formation by Cd treatment in aux1-7 and pin2 mutants than that in the WT. Meanwhile, Cd stress also altered the expression of PINs and AUX1 in Arabidopsis roots, implying that the auxin transport pathway is required for Cd-modulated LR development. Taken together, these findings suggest that Cd stress disturbs auxin homeostasis through affecting auxin level, distribution, metabolism, and transport in Arabidopsis seedling.

  20. Proteomic Study for Responses to Cadmium Stress in Rice Seedlings

    Institute of Scientific and Technical Information of China (English)

    GE Cai-lin; WANG Ze-gang; WAN Ding-zhen; DING Yan; WANG Yu-long; SHANG Qi; LUO Shi-shi

    2009-01-01

    A proteomic approach including two-dimensional electrophoresis and mass spectrometric (MALDI-TOF MS) analyses was used to investigate the responses to cadmium (Cd) stress in seedlings of rice (Oryza sativa L.) varieties Shanyou 63 and Aizaizhan. Cd stress significantly inhibited root and shoot growth, and affected the global proteome in rice roots and leaves, which induced or upregulated the expression of corresponding proteins in rice roots and leaves when rice seedlings were exposed to 0.1 or 1.0 mmol/L Cd. The Cd-induced proteins are involved in chelation and compartmentation of Cd, elimination of active oxygen free radicals, detoxification of toxic substances, degradation of denatured proteins or inactivated enzymes, regulation of physiologic metabolism and induction of pathogenesis-related proteins. Comparing the Cd-induced proteins between the two varieties, the β-glucosidase and pathogenesis-related protein family 10 proteins were more drastically induced by Cd stress in roots and leaves of Aizaizhan, and the UDP-glucose protein transglucosylase and translational elongation factor Tu were induced by 0.1 mmol/L Cd stress in roots of Shanyou 63. This may be one of the important mechanisms for higher tolerance to Cd stress in Shanyou 63 than in Aizaizhan.

  1. Continuous Spectrum LEDs Promote Seedling Quality Traits and Performance of Quercus ithaburensis var. macrolepis.

    Science.gov (United States)

    Smirnakou, Sonia; Ouzounis, Theoharis; Radoglou, Kalliopi M

    2017-01-01

    Regulation of the growth, development, and quality of plants by the control of light quality has attracted extensive attention worldwide. The aim of this study was to examine the effects of continuous LED spectrum for indoor plant pre-cultivation and to investigate the morphological and physiological responses of a common broadleaved tree species in Mediterranean environment, Quercus ithaburensis var. macrolepis at seedling developmental stage. Thus, the seedlings were pre-cultivated for 28 days, under five different LED light qualities: (1) Fluorescent (FL) as control light (2) L20AP67 (high in green and moderate in far-red), (3) AP673L (high in green and red), (4) G2 (highest in red and far-red), AP67 (high in blue, red, and far-red), and (5) NS1 (highest in blue and green and lowest in far-red) LEDs. Further examination was held at the nursery for 1 year, on several seedling quality traits. Indeed, AP67 and AP673L triggered higher leaf formation, while L20AP67 positively affected seedling shoot development. NS1 and AP67 LED pre-cultivated seedlings showed significantly higher root fibrosity than those of FL light. Furthermore, NS1 and AP673L LEDs induced fourfold increase on seedling root dry weight than FL light. Hence, evaluating the seedling nursery performance attributes, most of those photomorphogenetic responses previously obtained were still detectable. Even more so, LED pre-cultivated seedlings showed higher survival and faster growth indicating better adaptation even under natural light conditions, a fact further reinforced by the significantly higher Dickson's quality index acquired. In conclusion, the goal of each nursery management program is the production of high quality seedlings with those desirable traits, which in turn satisfy the specific needs for a particular reforestation site. Thus, the enhanced oak seedling quality traits formed under continuous LEDs spectrum especially of NS1 and AP673L pre-cultivation may potentially fulfill this goal.

  2. Interannual variation in rainfall, drought stress and seedling mortality may mediate monodominance in tropical flooded forests.

    Science.gov (United States)

    Lopez, Omar R; Kursar, Thomas A

    2007-11-01

    Flood tolerance is commonly regarded as the main factor explaining low diversity and monodominance in tropical swamps. In this study we examined seedling mortality in relation to seasonality, i.e., flooding versus drought, of the dominant tree species (Prioria copaifera), and three associated species (Pterocarpus officinalis, Carapa guianensis and Pentaclethra macroloba), in seasonally flooded forests (SFF) in Darien, Panama. Seedling mortality differed among species, years and seasons. Prioria seedlings experienced the lowest overall mortality, and after 3 years many more Prioria seedlings remained alive than those of any of the associated species. In general, within species, larger seedlings had greater survival. Seed size, which can vary by close to 2 orders of magnitude in Prioria, had a confounding effect with that of topography. Large-seeded Prioria seedlings experienced 1.5 times greater mortality than small-seeded seedlings, as large-seeded Prioria seedlings were more likely to be located in depressions. This finding suggests that seed size, plant size and topography are important in understanding SFF regeneration. For all species, seedling mortality was consistently greater during the dry season than during flooding. For Prioria, dry season seedling mortality was correlated with drought stress, that is, high mortality during the long El Niño dry season of 1998 and the normal dry season of 2000, but very low dry season mortality during the mild dry season of 1999. Prioria's ability to dominate in seasonally flooded forest of Central America is partly explained by its low drought-related mortality in comparison to associated species.

  3. Periodic exposure to ambient solar irradiance benefits the growth of juvenile seedlings of Hizikia fusiformis

    Institute of Scientific and Technical Information of China (English)

    SHAN Tifeng; PANG Shaojun; GAO Suqin

    2011-01-01

    In our trials,from 2007 to 2008,of mass production of seedlings of Hizikiafusiformis using synchronization techniques,problems of a “dark thalli” phenomenon and epiphytes contamination severely threatened the health of juvenile seedlings.In this investigation,we optimized conditions for improving the growth of juvenile seedlings.Seven string collectors were seeded with zygotes and a series of experiments were conducted including direct exposure to solar irradiance,co-culture with Ulva spp.and treatment with sodium hypochlorite.It was found that direct exposure to solar irradiance (maximum:1 740 μmol photons/(m2·s)) for 2 h per day could efficiently enhance the growth of young seedlings and simultaneously inhibit the growth of epiphytic algae.In this treatment,50-day old seedlings could reach an average of 0.44 cm in length and possess up to nine leaflets.However,a single treatment with 18-mmol/L sodium hypochlorite for 10 min severely harmed 15-day old seedlings.In comparison,weekly treatment with 2.2-mmol/L sodium hypochlorite for 10 min brought no apparent harm to seedlings and eliminated epiphytic algae efficiently.However,this treatment significantly increased the detachment rate of seedlings.Inoculating Ulva spp.onto the collector caused a dramatic decrease in the number of seedlings.However,the growth of the remaining seedlings appeared unhampered.All collectors except the control were daily sprayed with a high pressure water jet from the 8th day post fertilization.From the first day to 50th day,no “dark thallus” was observed on any of the seven collectors.We believe that well-timed daily exposure to solar irradiance would favor H.fusiformis in its early growing stages.

  4. Effect of Fertilization on the Morphological Development of European Hophormbeam (Ostrya carpinifolia Scop. Seedlings

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    Şemsettin Kulaç

    2016-10-01

    Full Text Available In this study, in order to help the mass production of seedlings, the effect of fertilization on the morphological development of hornbeam leafy European hophornbeam (Ostry carpinifolia Scop seedlings were investigated. For this, seedlings, which were obtained from the seeds coming from different European hophornbeam populations (Düzce-Yığılca, Antalya-Finike, Antalya-Akseki, Kastamonu-Şehdağ ve Adana-Saimbeyli from various parts of Turkey, were used. European hophornbeam seedlings were treated with different fertilizers, including urea, ammonium sulphate, compound fertilizer 15-15-15 and 20-20-0, and 6-9 months Osmocote release fertilizer, and effects of these fertilizers on the morphological characters were investigated. Fertilization contained the same amount of nitrogen, and was made in three different ways; (1 mixing with habitat, (2 topical application and (3 liquid application. The development of germinated European hophornbeam seeds, which were spring-sowed in the same medium were monitored during the vegetation period. At the end of vegetation period, seedlings were removed from the soil and morphological characteristics of root (seedling length, root collar diameter, root length, fresh root and stem weight of the seedlings, dried root and stem weight of the seedlings and bud number were measured. As a result, it was observed that fertilization positively affects the development of seedlings and depending on the fertilization type the seedlings of European hophornbeam populations were found to exhibit different improvements/growing. In addition, 6-9 months Osmocote release fertilizers were determined to be the best fertilizers affecting the morphological (diameter and height development of European hophornbeam populations effectively, and among the populations, Düzce and Kastamonu populations showed the best improvement/growing.

  5. The influence of seedling density in containers on morphological characteristics of European beech

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    Wrzesiński Piotr

    2015-09-01

    Full Text Available This study examines the influence on growth parameters, in particular the morphological features of the root system, of 1-year-old European beech seedlings cultivated in containers with two different densities. The experiment was conducted in the container nursery in Skierdy (Forest District of Jabłonna in spring 2011. After 10 months of cultivation in Hiko polyethylene containers, above- and below-ground parts of the seedlings were measured. The measurements of the root system were conducted with a scanner and the WinRHIZO software. No influence due to the seedling density on either shoot height or thickness was observed, but instead the research showed that different seedling densities affected the development of root systems. The mean root thickness and dry mass of the European beech seedlings were significantly higher at the lower density. The influence of seedling density on the development of root mass deserves special attention as it is the most important factor affecting future growth of the seedlings during cultivation. This tendency also suggests that the amount of nutrients allocated to shoot development may be higher in order to improve the efficiency of photosynthesis. At both densities, differences in biomass accumulation affected the root-toshoot ratio. In seedlings cultivated at the lower density, the increased dry root matter of the seedlings resulted in a significant increase in the root-to-shoot ratio. This may cause a potential growth advantage of these seedlings after they are planted and may thus result in a more productive cultivation.

  6. [Growth, survival and herbivory of seedlings in Brosimum alicastrum (Moraceae), a species from the Neotropical undergrowth].

    Science.gov (United States)

    Ballina-Gómez, H S; Iriarte-Vivar, S; Orellana, R; Santiago, L S

    2008-12-01

    Growth responses, survival, and herbivory, on seedlings of Brosimum alicastrum were studied in a neotropical Mexican forest. We selected 122 seedlings and divided them into three groups assigned to defoliation treatments: control or 0 (n=21), 50 (n=51) and 90% (n=50). Every 4 months during two years we measured seedling growth (in terms of relative growth rate in biomass, leaf area growth, produced leaves and height growth) and survival. In addition, we evaluated every 12 months pathogen damage and insect herbivory using a 2 mm(-2) grid. Separately, we estimated mammal herbivory in 3-month old seedlings that were selected within a plot of 500 m x 10 m (N=1095). Pathogen damage and insect herbivory were evaluated within the same plot in 113 seedlings. We found that 50% defoliated seedlings showed compensatory responses in all growth parameters. Relative growth rate and height growth also had a compensatory response in seedlings at 90% defoliation. Relative growth rate and leaf area growth gradually decreased with time although height growth seedling showed an opposite pattern. Leaves produced were not affected by time. Estimated seedling survival probability increased with defoliation to a maximum of 97%, decreasing at 24 month to 37%. Mammal herbivory was more frequent and severe than herbivory caused by pathogens and insects. In some cases, mammal herbivory produced total defoliation. Compensatory growth in leaf area growth, produced leaves and height growth seedling suggest a synergic compensatory mechanism expressed in a whole-plant growth biomass (relative growth rate). Compensation and survival results suggest trade-offs at the leaf level, such as leaf area growth and produced leaves versus chemical defenses, respectively.

  7. Mineral elements of subtropical tree seedlings in response to elevated carbon dioxide and nitrogen addition.

    Directory of Open Access Journals (Sweden)

    Wenjuan Huang

    Full Text Available Mineral elements in plants have been strongly affected by increased atmospheric carbon dioxide (CO2 concentrations and nitrogen (N deposition due to human activities. However, such understanding is largely limited to N and phosphorus in grassland. Using open-top chambers, we examined the concentrations of potassium (K, calcium (Ca, magnesium (Mg, aluminum (Al, copper (Cu and manganese (Mn in the leaves and roots of the seedlings of five subtropical tree species in response to elevated CO2 (ca. 700 μmol CO2 mol(-1 and N addition (100 kg N ha(-1 yr(-1 from 2005 to 2009. These mineral elements in the roots responded more strongly to elevated CO2 and N addition than those in the leaves. Elevated CO2 did not consistently decrease the concentrations of plant mineral elements, with increases in K, Al, Cu and Mn in some tree species. N addition decreased K and had no influence on Cu in the five tree species. Given the shifts in plant mineral elements, Schima superba and Castanopsis hystrix were less responsive to elevated CO2 and N addition alone, respectively. Our results indicate that plant stoichiometry would be altered by increasing CO2 and N deposition, and K would likely become a limiting nutrient under increasing N deposition in subtropics.

  8. Nitrogen deficiency in barley (Hordeum vulgare) seedlings induces molecular and metabolic adjustments that trigger aphid resistance.

    Science.gov (United States)

    Comadira, Gloria; Rasool, Brwa; Karpinska, Barbara; Morris, Jenny; Verrall, Susan R; Hedley, Peter E; Foyer, Christine H; Hancock, Robert D

    2015-06-01

    Agricultural nitrous oxide (N2O) pollution resulting from the use of synthetic fertilizers represents a significant contribution to anthropogenic greenhouse gas emissions, providing a rationale for reduced use of nitrogen (N) fertilizers. Nitrogen limitation results in extensive systems rebalancing that remodels metabolism and defence processes. To analyse the regulation underpinning these responses, barley (Horedeum vulgare) seedlings were grown for 7 d under N-deficient conditions until net photosynthesis was 50% lower than in N-replete controls. Although shoot growth was decreased there was no evidence for the induction of oxidative stress despite lower total concentrations of N-containing antioxidants. Nitrogen-deficient barley leaves were rich in amino acids, sugars and tricarboxylic acid cycle intermediates. In contrast to N-replete leaves one-day-old nymphs of the green peach aphid (Myzus persicae) failed to reach adulthood when transferred to N-deficient barley leaves. Transcripts encoding cell, sugar and nutrient signalling, protein degradation and secondary metabolism were over-represented in N-deficient leaves while those associated with hormone metabolism were similar under both nutrient regimes with the exception of mRNAs encoding proteins involved in auxin metabolism and responses. Significant similarities were observed between the N-limited barley leaf transcriptome and that of aphid-infested Arabidopsis leaves. These findings not only highlight significant similarities between biotic and abiotic stress signalling cascades but also identify potential targets for increasing aphid resistance with implications for the development of sustainable agriculture.

  9. Nutrient omission effect on growth and nutritional status of assai palm seedlings

    Directory of Open Access Journals (Sweden)

    Fábio Reis Ribeiro Araújo

    2016-12-01

    Full Text Available The Amazonian assai palm has a great socioeconomic importance, but most of its commercial plantations take place in uplands and low natural fertility soils, what may hinder its development. This study aimed at evaluating the effect of nutrient omission on growth and nutritional status of assai palm seedlings (Ver-o-Peso cultivar. The experimental design was completely randomized, with 14 treatments and 5 replicates. The treatments consisted of complete fertilization with liming; no fertilization and no liming (control; complete fertilization with individual omission of N, P, K, Ca, Ca with no liming, Mg, Mg with no liming, S, B, Cu and Zn. Plant height, stem diameter and dry mass, leaf and total shoot dry mass, and leaf nutrients content and accumulation were evaluated. The initial growth of the assai palm plants was limited by the omission of P, N, K, Ca, Mg and Cu. The production of leaf dry mass was decreasingly affected by the omission of P > Cu > N > K > Mg, while leaf area was limited by the individual omissions of Ca > N > P > K > Mg > Zn. Plant development, measured by relative growth of shoots, was affected by lack of Ca > P > N > Mg > Cu > K, with an average reduction of 31 %. The nutrients most needed by the assai palm plants, as evidenced by nutrients contents and accumulation in the leaf dry mass, are: N > K > S > Ca > Mg > P > Mn > Zn > B > Cu.

  10. Effects of inorganic amendments (urea, gypsum) on seed germination and seedling recruitment of 20 native plant species used in dryland restoration

    Science.gov (United States)

    Bateman, Amber; E Erickson, Todd; Merritt, David J.; Muñoz-Rojas, Miriam

    2017-04-01

    affected by higher doses of gypsum and urea amendments. In the lower dose treatments, however, the total biomass of seedlings showed a positive effect for species from the Amaranthaceae. There was no apparent effect on species from the Fabaceae, Malvaeceae, Myrtaceae, and Poaceae families. Small doses of the amendments had a positive impact on the seed germination for three of the five evaluated species (Acacia bivenosa, Triodia wiseana and, Senna notabilis). Yet, despite the addition of soil amendments there was a high rate of mortality between the germination and emergence phases, a common occurrence in arid zone species subject to extreme environmental conditions (James et al., 2011). Seedling emergence of Acacia bivenosa and Triodia wiseana in TW and W substrates with low doses of urea achieved levels comparable to emergence in topsoil. Overall, responses to the inorganic amendments varied considerably across species and long-term field studies are required to assess plant responses in a restoration setting. Nevertheless, the findings of this suggest that the addition of these N-based inorganic amendments at low concentrations will benefit some plant species and improve arid zone restoration. References James JJ, Svejcar TJ, Rinella MJ. 2011. Demographic processes limiting seedling recruitment in arid grassland restoration. Journal of Applied Ecology, 48, 961-969 Muñoz-Rojas M, Erickson TE, Martini D, Dixon KW, Merritt DJ. 2016. Climate and soil factors influencing seedling recruitment of plant species used for dryland restoration. SOIL, 2, 1-11, DOI: 10.5194/soil-2016-25

  11. Comparative Effects of Drought and Salt Stress on Germination and Seedling Growth of Pennisetum divisum (Gmel. Henr.

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    Wafaa A. Al-Taisan

    2010-01-01

    Full Text Available Problem statement: Water stress due to drought and salinity is probably the most significant abiotic factor limiting plant and also crop growth and development. Salinity and drought stresses are physiologically related, because both induce osmotic stress and most of the metabolic responses of the affected plants are similar to some extent. Water deficit affects the germination of seed and the growth of seedlings negatively. Temperature is an exceedingly important factor in seed germination. It directly affects whether a plant can sprout and, if so, how long it will take to emerge from the ground. Approach: The objective of this investigation was to determine the effect of four alternating temperature regime, drought and salt stress on germination characteristics of Pennisetum divisum. Seeds were germinated at four alternating temperatures (10/20, 15/25, 20/35 and 25/40°C at 12 h light. Seeds were also germinated with the iso-osmotic concentrations of sodium chloride (NaCl or in polyethylene glycol PEG8000 (0, -0.2, -0.4, -0.6 and -0.8 MPa for 14 days. Concentrations were applied to determine their effects on seed germination and seedling growth under laboratory conditions. The effects of different osmotic concentrations of NaCl and PEG were compared to distilled water (control. Results: Optimum germination was attained at 15/25°C which corresponds to temperatures prevailing during spring time. The highest values of germination parameters were obtained with no osmotic potential (0 MPa under 15/25°C. The final germination percentage and rate of germination in the Pennisetum divisum treated seeds were decreased with the increase of the osmotic potential. At treatment by PEG, the germination was severely decreased at -0.6 MPa. While, no germination occurred at- 0.8 MPa by NaCl. The results of the effects of the different osmotic potential of NaCl and PEG on the Radicle Length (RL and the Hypocotyl Length (HL mm of the tested P. divisum

  12. Growth response of Douglas-fir seedlings to nitrogen fertilization: importance of Rubisco activation state and respiration rates.

    Science.gov (United States)

    Manter, Daniel K; Kavanagh, Kathleen L; Rose, Cathy L

    2005-08-01

    effects of maximum Rubisco carboxylation, Rdark and KL responses to N fertilization may limit seedling production when foliar N exceeds about 13 mg g(-1) or is reduced to less than about 11 mg g(-1).

  13. Effect of Different Irrigation and Fertilizer Treatments on the Seedlings Growth of Cupressus torulosa in Containers%不同水肥处理对藏柏容器苗生长的影响

    Institute of Scientific and Technical Information of China (English)

    胡丁猛; 臧真荣; 王翠香; 王开芳; 任飞; 吴德军

    2012-01-01

    [目的]探讨藏柏轻基质容器苗生长与水肥处理的关系.[方法]对藏柏一年生轻基质容器苗进行不同的水肥处理,在生长季结束后调查地径和苗高.[结果]藏柏容器苗地径和苗高生长量分别随施肥量和浇水次数增多而增大;A1B1组合(1d1次,施肥0.1 g),地径平均生长量最大;A1B2组合(1d1次,施肥0.2g),苗高平均生长量最大.[结论]水分为藏柏轻基质容器苗生长的限制因子.%[Objective] The aim was to discuss the relationship between -the seedlings growth of Cupressus torulosa in containers with light medium and the irrigation and fertilizer treatments. [ Method ] One-year-old seedlings of Cupressus torulosa in containers with light medium were treated by different irrigation and fertilizer treatments, the height and basal diameter of seedlings were measured after the growing season. [ Result] The value of seedlings height and basal diameter rose with the increase of the weight of fertilizer and watering frequency respectively; value of seedling height reached the maximum when watering once each day and fertilized 0. 1 g, namely A1B2 combination, and so did the value of basal diameter as watering once ten days and fertilized 0.2 g, namely A1 B2 combination. [ Conclusion] Water is the limiting factor for seedlings growth of Cupressus torulosa in containers with light medium.

  14. Preparation of Microencapsulated Bacillus subtilis SL-13 Seed Coating Agents and Their Effects on the Growth of Cotton Seedlings

    Directory of Open Access Journals (Sweden)

    Liang Tu

    2016-01-01

    Full Text Available Inoculation of the bacterial cells of microbial seed coating agents (SCAs into the environment may result in limited survival and colonization. Therefore, the application efficacy of an encapsulated microbial seed coating agent (ESCA was investigated on potted cotton plants; the agent was prepared with polyvinyl alcohol, sodium dodecyl sulfate, bentonite, and microencapsulated Bacillus subtilis SL-13. Scanning electron micrography revealed that the microcapsules were attached to ESCA membranes. The ESCA film was uniform, bubble-free, and easy to peel. The bacterial contents of seeds coated with each ESCA treatment reached 106 cfu/seed. Results indicated that the germination rate of cotton seeds treated with ESCA4 (1.0% (w/v sodium alginate, 4.0% polyvinyl alcohol, 1.0% sodium dodecyl sulfate, 0.6% acacia, 0.5% bentonite, and 10% (v/v microcapsules increased by 28.74%. Other growth factors of the cotton seedlings, such as plant height, root length, whole plant fresh weight, and whole plant dry weight, increased by 52.70%, 25.13%, 46.47%, and 33.21%, respectively. Further analysis demonstrated that the peroxidase and superoxide dismutase activities of cotton seedlings improved, whereas their malondialdehyde contents decreased. Therefore, the ESCA can efficiently improve seed germination, root length, and growth. The proposed ESCA exhibits great potential as an alternative to traditional SCA in future agricultural applications.

  15. Preparation of Microencapsulated Bacillus subtilis SL-13 Seed Coating Agents and Their Effects on the Growth of Cotton Seedlings.

    Science.gov (United States)

    Tu, Liang; He, Yanhui; Shan, Chunhui; Wu, Zhansheng

    2016-01-01

    Inoculation of the bacterial cells of microbial seed coating agents (SCAs) into the environment may result in limited survival and colonization. Therefore, the application efficacy of an encapsulated microbial seed coating agent (ESCA) was investigated on potted cotton plants; the agent was prepared with polyvinyl alcohol, sodium dodecyl sulfate, bentonite, and microencapsulated Bacillus subtilis SL-13. Scanning electron micrography revealed that the microcapsules were attached to ESCA membranes. The ESCA film was uniform, bubble-free, and easy to peel. The bacterial contents of seeds coated with each ESCA treatment reached 10(6) cfu/seed. Results indicated that the germination rate of cotton seeds treated with ESCA4 (1.0% (w/v) sodium alginate, 4.0% polyvinyl alcohol, 1.0% sodium dodecyl sulfate, 0.6% acacia, 0.5% bentonite, and 10% (v/v) microcapsules) increased by 28.74%. Other growth factors of the cotton seedlings, such as plant height, root length, whole plant fresh weight, and whole plant dry weight, increased by 52.70%, 25.13%, 46.47%, and 33.21%, respectively. Further analysis demonstrated that the peroxidase and superoxide dismutase activities of cotton seedlings improved, whereas their malondialdehyde contents decreased. Therefore, the ESCA can efficiently improve seed germination, root length, and growth. The proposed ESCA exhibits great potential as an alternative to traditional SCA in future agricultural applications.

  16. Seasonal patterns of photosynthetic light response in Douglas-fir seedlings subjected to elevated atmospheric CO(2) and temperature.

    Science.gov (United States)

    Lewis, J. D.; Olszyk, D.; Tingey, D. T.

    1999-04-01

    Increases in atmospheric CO(2) concentration and temperature are predicted to increase the light response of photosynthesis by increasing light-saturated photosynthetic rates and apparent quantum yields. We examined the interactive effects of elevated atmospheric CO(2) concentration and temperature on the light response of photosynthesis in Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seedlings. Seedlings were grown in sunlit chambers controlled to track either ambient (~400 ppm) CO(2) or ambient + 200 ppm CO(2), at ambient temperature or ambient + 4 degrees C. Photosynthetic light response curves were measured over an 18-month period beginning 32 months after treatments were initiated. Light-response curves were measured at the growth CO(2) concentration, and were used to calculate the light-saturated rate of photosynthesis, light compensation point, quantum yield and respiration rate. Elevated CO(2) increased apparent quantum yields during two of five measurement periods, but did not significantly affect light-saturated net photosynthetic rates, light compensation points or respiration rates. Elevated temperature increased all parameters. There were no significant interactions between CO(2) concentration and temperature. We conclude that down-regulation of photosynthesis occurred in the elevated CO(2) treatments such that carbon uptake at a given irradiance was similar across CO(2) treatments. In contrast, increasing temperature may substantially increase carbon uptake rates in Douglas-fir, assuming other environmental factors do not limit photosynthesis; however, it is not clear whether the increased carbon uptake will increase growth rates or be offset by increased carbon efflux through respiration.

  17. Nitric oxide induced by polyamines involves antioxidant systems against chilling stress in tomato (Lycopersicon esculentum Mill.) seedling*#

    Science.gov (United States)

    Diao, Qian-Nan; Song, Yong-Jun; Shi, Dong-Mei; Qi, Hong-Yan

    2016-01-01

    Polyamines (PAs) and nitric oxide (NO) are vital signals in modulating plant response to abiotic stress. However, to our knowledge, studies on the relationship between NO and PAs in response to cold stress in tomato are limited. Accordingly, in this study, we investigated the effects of putrescine (Put) and spermidine (Spd) on NO generation and the function of Spd-induced NO in the tolerance of tomato seedling under chilling stress. Spd increased NO release via the nitric oxide synthase (NOS)-like and nitrate reductase (NR) enzymatic pathways in the seedlings, whereas Put had no such effect. Moreover, H2O2 might act as an upstream signal to stimulate NO production. Both exogenous NO donor (sodium nitroprusside (SNP)) and Spd enhanced chilling tolerance in tomato, thereby protecting the photosynthetic system from damage. Compared to chilling treatment alone, Spd enhanced the gene expressions of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX), and their enzyme activities in tomato leaves. However, a scavenger or inhibitor of NO abolished Spd-induced chilling tolerance and blocked the increased expression and activity due to Spd of these antioxidant enzymes in tomato leaves under chilling stress. The results showed that NO induced by Spd plays a crucial role in tomato’s response to chilling stress. PMID:27921397

  18. Nitric oxide induced by polyamines involves antioxidant systems against chilling stress in tomato (Lycopersicon esculentum Mill.) seedling.

    Science.gov (United States)

    Diao, Qian-Nan; Song, Yong-Jun; Shi, Dong-Mei; Qi, Hong-Yan

    Polyamines (PAs) and nitric oxide (NO) are vital signals in modulating plant response to abiotic stress. However, to our knowledge, studies on the relationship between NO and PAs in response to cold stress in tomato are limited. Accordingly, in this study, we investigated the effects of putrescine (Put) and spermidine (Spd) on NO generation and the function of Spd-induced NO in the tolerance of tomato seedling under chilling stress. Spd increased NO release via the nitric oxide synthase (NOS)-like and nitrate reductase (NR) enzymatic pathways in the seedlings, whereas Put had no such effect. Moreover, H2O2 might act as an upstream signal to stimulate NO production. Both exogenous NO donor (sodium nitroprusside (SNP)) and Spd enhanced chilling tolerance in tomato, thereby protecting the photosynthetic system from damage. Compared to chilling treatment alone, Spd enhanced the gene expressions of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX), and their enzyme activities in tomato leaves. However, a scavenger or inhibitor of NO abolished Spd-induced chilling tolerance and blocked the increased expression and activity due to Spd of these antioxidant enzymes in tomato leaves under chilling stress. The results showed that NO induced by Spd plays a crucial role in tomato's response to chilling stress.

  19. Influence of water logging time on the growth of candel seedlings

    Institute of Scientific and Technical Information of China (English)

    CHEN Luzhen; WANG Wenqing; LIN Peng

    2004-01-01

    Influence ofwaterlogging time on the growth ofKandeliacandel(L.) Druce seedlings grown for 70 d in the artificial-tidal tanks' simulated semidiumal tide under greenhouse is studied. Sand and soil act as the substrate and artificial sea-water with salinity of 15 is used in cultivation. Shorter waterlogging time (inundated for about 2 ~ 4 h) promotes thegrowth of K. candel seedlings, while longer time(inundated more than 8 h) or no waterlogging(0 h) inhibits theirgrowth. The number and length of aerating roots increase with the increase ofwaterlogging time. Under existing condi-tions, the optimalwaterlogging time for the growth of K. canoel seedlings is about 2 ~ 4 h in every tide cycle. Com-pared with other treatments, the 2 h sanded treatments obtain the highest biomass of seedlings, have the lowest massloss ofhypocotyl and broaden the photosynthetic area by increasing the area per leaf after 70-d cultivation. And the soiltreatments have the similar tendeney. However, waterlogging for 8 h in every tide cycle is critieal for normal develop-ment of seedlings. K. candel seedlings are highly tolerant to waterlogging and a proper waterlogging is beneficial to thegrowth ofK. candel seedlings.

  20. Short-term toxic effects of chlorobenzenes on broadbean (Vicia faba) seedlings

    Institute of Scientific and Technical Information of China (English)

    LIU; Wan; LI; Peijun; ZHOU; Qixing; SUN; Tieheng; TAI; Peid

    2005-01-01

    The root growth, changes in superoxide dismutase (SOD, EC 1.15.1.1) activity,malonyldialdehyde (MDA) and total soluble protein level of broadbean (Vicia faba) seedlings were researched at different soil concentrations of chlorobenzene (CB), 1,2,4-trichlorobenzene (TCB) and hexachlorobenzene (HCB). The results showed that root growth of seedlings was growth was, however, restored to some extent although there was a delay in returning to the control level. The total soluble protein content in seedlings increased with TCB concentration and duration of exposure. Effect of TCB stress on SOD activity in seedlings displayed a significant were placed in clean tap water for 3 d following exposure to 5 d of TCB stress to clear tap water (P<0.05). The experiments also revealed that a significant increase of MDA level in seedlings was a positive correlation between TCB concentration and MDA level. All the above results showed that SOD activity and MDA level of broadbean seedlings might be proposed as the biomarkers for short-term TCB contamination in soil. Compared to TCB, the toxicity of 50-1000 μg · g-1 CB or HCB in soil to broadbean seedlings was not observed after a 3 d exposure.

  1. Effect of electrostatic field on seed germination and seedling growth of Sorbus pohuashanesis

    Institute of Scientific and Technical Information of China (English)

    YANG Ling; SHEN Hai-long

    2011-01-01

    A study was conducted to determine the effects of electro static field (ESF) treatment on seed germination and seedling growth of Sorbus pohuashanesis. The experiments were arranged by uniform design computed by the Data Processing System (DPS), including three levels of seeds soaking time, four levels of ESF intensity and four levels of ESF treatment time, with 12 treatments. Ten seeds were used in each treatment with three replicates. Seed vigor, seed germinating ability,emergence rate of seedling, survival rate of seedling, and seedling height and diameter, as well as the change in activities of superoxide dismutase (SOD), soluble protein contents, total chlorophyll contents, soluble total sugar contents in leaves of S. pohuashanensis seedlings were measured after ESF treatments. The experiment results show that ESF treatment could improve the water absorption ability of dry seeds of S. pohuashanensis, resulting in fast germination at room temperature under light conditions. Combined treatment of ESF with cold stratification could increase seed germination percentage significantly (to 42.20%),promote seedling height growth, affect leaf SOD activity, and could raise contents of total chlorophyll, soluble protein, and total soluble sugar in leaves. Seed soaking time had a significant effect on seed relative electroconductivity, seed germination under light, SOD activity, soluble protein content and total soluble sugar content of seedling leaves. ESF intensity exerted a moderate effect on these indexes. ESF treatment time only had significant effect on total chlorophyll contents, no evident effect on other indexes.

  2. Use of aquatic macrophytes in substrate composition to produce moringa seedlings

    Directory of Open Access Journals (Sweden)

    Walda Monteiro Farias

    2016-03-01

    Full Text Available The use of aquatic macrophytes in substrate composition to produce seedlings of moringa is a sustainable alternative. Therefore, the objective of this research was to evaluate the development of moringa seedlings using substrates composed with aquatic macrophytes, and to determine concentrations of N, P and K in the seedlings. We used different combinations of weeds (M, manure (E and topsoil (TV to compose the substrates. The experiment was conducted in a 3 × 4 factorial in randomized arrangement with four replications. We evaluated plant height, crown diameter and stem, relative growth rate in height, canopy diameter and in stem, dry matter of aerial part and of roots, root length and root/shoot ratio, besides the content of N, P and K in seedlings. Moringa seedlings showed reduced growth when produced in substrates composed only with cattail. Water lettuce and substrates composed of 60% M + 30%E + 10 % TV and 70% M + 30% E, promoted greater nutrition and growth of moringa seedlings. The substrate 60M +30E +10TV composed by water hyacinth and cattail resulted in greater amount of P in moringa seedlings.

  3. Leaching of nitrogen and phosphorus during production of forest seedlings in containers.

    Science.gov (United States)

    Juntunen, Marja-Liisa; Hammar, Taina; Rikala, Risto

    2002-01-01

    Little information is available concerning the contamination risk caused by forest seedling nurseries to local surface and ground waters compared with agricultural and horticultural production. Leaching of nitrogen (N) and phosphorus (P) through peat growing medium in containers and nutrient uptake of seedlings were monitored in production of silver birch (Betula pendula Roth), Norway spruce [Picea abies (L.) Karst], and Scots pine (Pinus sylvestris L.) seedlings. About half of the applied nutrients (total amount applied = 149 to 260 kg N ha(-1) and 60 to 108 kg P ha(-1)) was premixed into the peat medium, as is usual in Finnish nursery practice, and the other half was applied to seedlings in liquid form with mobile booms. Depending on tree species, 11 to 19% of the applied N was recovered in leachates and 15 to 63% in seedlings. The undiscovered proportion varied from 19 to 71%. The amounts of leached N were 19 to 41 kg ha(-1). Only 5 to 31% of the applied P was recovered in seedlings; 16 to 64% (11 to 56 kg ha(-1)) was found in leachates. Total N and P load to the environment may increase substantially if nutrients applied in liquid fertilization outside container trays are included. Consequently, it is important to determine the sources of nutrient load in container seedling production to mitigate the risk of environment contamination.

  4. Injuries on Seedlings Caused by Potential Weed in Tropical Rain Forest Regeneration Areas

    Directory of Open Access Journals (Sweden)

    Sumardi Sumardi

    2000-07-01

    Full Text Available The experiment aimed to assess the injuries on Shorea seedlings caused by weed in artificial regeneration of tropical rain forest in Jambi. Four planting systems, strip nurse planting (using Acacia mangium, Paraserianthes falcataria and Gmelina arborea, line planting, gap planting and natural regeneration, were used. Seedling injuries were assessed based on part of seedling suppressed. Results indicated that Shorea seedling suffered from varying degrees of injuries, depending on weed species and part of the seedling suppressed. The dominance of weed and damage intensity were determined by the level of canopy opening on the planting systems. Ground cover dominated rapidly in open canopy, causing up to 55.27% injuries on the seedlings in the strips of G. arborea and P. falcataria. Whereas creepers and vines became dominant in moderate canopy opening. The injury of Shorea seedling planted under nurse tree was determined by the species and planting density of nurse tree used. Light canopy nurse tree such as P. falcataria failed to suppress ground weed, but in the contrary, A. mangium with heavy canopy still allowed creepers and vines to grow.

  5. Use of plant residues on growth of mycorrhizal seedlings of neem (Azadirachta indica A. Juss.).

    Science.gov (United States)

    Monte Júnior, Inácio P; Maia, Leonor C; Silva, Fábio S B; Cavalcante, Uided M T

    2012-02-01

    Owing to its multiple uses in veterinary medicine, biofertilizers, pest control, etc., the commercial cultivation of neem (Azadirachta indica) has been increasing in various countries. The use of arbuscular mycorrhizal fungi (AMF) and plant by-products (composted leaves and residues of neem and sugarcane) for the propagation of seedlings can be an efficient alternative to stimulate plant growth, reducing the propagation time and conferring increased tolerance of plants to biotic and abiotic stresses. Therefore this study aimed to evaluate the effect of plant substrates and inoculation with AMF on the production of neem seedlings. Beneficial effects of the application of neem by-products to neem seedlings were observed on most of the variables analysed. However, the treatment with sugarcane cake did not improve the growth of neem seedlings. In general, the inoculation treatments using Glomus etunicatum in the composted neem substrates improved seedling growth. Neem by-products benefit the growth of seedlings of this plant under greenhouse conditions. Inoculation with G. etunicatum enhances plants growth mainly in substrates with residues of neem leaves, providing an alternative for the production of seedlings of this crop under nursery conditions, which can reduce the need for chemical fertilizers that impact the environment. Copyright © 2011 Society of Chemical Industry.

  6. GROWTH OF Jacaranda puberula Cham. SEEDLINGS IN NURSERY UNDER DIFFERENT SHADING LEVELS

    Directory of Open Access Journals (Sweden)

    Lausanne Soraya de Almeida

    2010-08-01

    Full Text Available Jacaranda puberula, known as caroba, is a species that presents potential use for the recovery of degraded areas, since it possesses fast growth and adapts well to sandy and loamy soils. It presents great aggressiveness in secondary forests and it can be used as urban tree because it produces beautiful lilac flowers. With the intention of obtaining information about potential species for use in recovery of riparian forest, were tested in the nursery of the city hall of the municipal district of Colombo, the development of seedlings of Jacaranda puberula submitted at 30, 50 and 70% of shading. There were used 40 seedlings by treatment and there were evaluated the following parameters: height (60, 90 and 120 days and diameter (90 and 120 days of all seedlings, leaf area and root and shoot dry weight of 6 seedlings per treatment. The largest averages of the analyzed variables were obtained for the 30% shading, except for root dry weight.  The seedlings exposed to full sun presented high mortality rate and was not compared to the others. The smallest averages of the analyzed variables, except for height, were observed for the shading of 70%, indicating that this treatment is not advisable for the production of seedlings of this species in nursery. The best condition for planting the seedlings appears to be in open areas with shading of 30 to 50%, since its natural occurrence is not at full exposure.

  7. Variation in Seedling Growth of Tamarindus indica (L.: A Threatening Medicinal Fruit Tree Species in Bangladesh

    Directory of Open Access Journals (Sweden)

    Md. Salim Azad

    2014-01-01

    Full Text Available Seedling growth is a precondition for conservation and sustainable use of genetic resources which depends upon understanding of breeding system, genetic inconsistency, and evolutionary forces in forest tree improvement. The aim of this study was to determine variation in seedling growth and age-age correlations of Tamarindus indica at population level in Bangladesh. The study revealed significant (P<0.05 differences of seasonal variation in seedling growth. Height and collar diameter growth showed significant (P<0.05 positive correlation with mean monthly rainfall. The study also revealed significant difference (P<0.05 of seedling growth among T. indica population. PCA illustrated rainfall, height growth, and diameter growth as the main characters in this study which defined drought as an additive character for this species. Cluster analysis of similarity showed how seedlings from 22.67°N latitude (origin separated from others. An increasing trend of age-age correlation was identified in both cases of shoot height and diameter growth. The study concluded that seed collection for either ex situ conservation or seedling production can be done from 22.67°N latitude as seedlings from that area performed better than others, and early clonal selection of T. indica can be done at the age of 9 months.

  8. Survey to Evaluate Escape of Eucalyptus spp. Seedlings from Plantations in Southeastern USA

    Directory of Open Access Journals (Sweden)

    Mac A. Callaham

    2013-01-01

    Full Text Available Interest in biomass-based energy in the southeastern Unites States has led to increased need for fast-growing tree species. Several Eucalyptus species exhibit characteristics that make them attractive in the bioenergy context. However, some of these also possess traits that suggest they could become invasive. To make a preliminary assessment of the risk of seedling establishment in the vicinity of Eucalyptus plantations, we conducted surveys at 3 sites in South Carolina and 16 sites in Florida. In South Carolina, no seedlings were detected in any sample transect. In Florida, we found seedlings within the boundaries of Eucalyptus plantations at 4 of the 16 sites surveyed. We also detected seedlings outside the boundaries of these same four plantations, but only two seedlings were detected at distances >45 m from plantation boundaries. All seedlings from Florida were either E. amplifolia, E. robusta, or E. grandis. The most predictive variable evaluated was latitude, with 27°N being the highest latitude at which seedlings established with regularity. Results of this survey indicate that, under current conditions, the spread of Eucalyptus spp. from plantations should be possible to manage with appropriate monitoring, but this should be evaluated further before Eucalyptus spp. are adopted for widespread planting.

  9. Growth and photosynthetic responses of Fraxinus mandshurica seedlings to various light environments

    Institute of Scientific and Technical Information of China (English)

    WANG Kai; ZHU Jiao-jun; YAN Qiao-ling; YU Li-zhong; SUN Yi-rong

    2011-01-01

    To determine light requirement and adaptability of Fraxinusmandshurica seedlings, the seasonal variations of photosynthetic vari-ables were measured in 3-year-old seedlings grown under four lightlevels (100%, 60%, 30%, and 15% of full sunlight) with a LI-6400 port-able photosynthesis system. The leaf chlorophyll content, special leafweight, annual height and basal diameter increment of seedlings werealso observed. The maximum and minimum values of net photosyntheticrate, maximum rate of carboxylation, and maximum rate of electrontransport of F. Mandshurica seedlings were detected with 60% and 15%of full sunlight treatments, respectively. With the decrease of light level,both light saturation point and special leaf weight significantly declined(p<0.05), but leaf chlorophyll content significantly increased (p<0.05).Annual height and basal diameter increments of seedlings grown under60% of full sunlight treatment were significantly greater than those ofseedlings under other treatments (p<0.05). It was concluded that F.mandshurica seedlings can adapt to a wide range of light environmentsfrom 15% to 100% of full sunlight by adjusting light saturation point,leaf chlorophyll content and special leaf weight. According to the maxi-mum of relative growth, 60% of full sunlight treatment is the optimumlight level for the growth of 3-year-old F. Mandshurica seedlings.

  10. Effect of CO2 Enrichment on the Growth and Nutrient Uptake of Tomato Seedlings

    Institute of Scientific and Technical Information of China (English)

    LI Juan; ZHOU Jian-Min; DUAN Zeng-Qiang; DU Chang-Wen; WANG Huo-Yan

    2007-01-01

    Exposing tomato seedlings to elevated CO2 concentrations may have potentially profound impacts on the tomato yield and quality. A growth chamber experiment was designed to estimate how different nutrient concentrations influenced the effect of elevated CO2 on the growth and nutrient uptake of tomato seedlings. Tomato (Hezuo 906) was grown in pots placed in controlled growth chambers and was subjected to ambient or elevated CO2 (360 or 720 μL L-1), and four nutrient solutions of different strengths (1/2-, 1/4-, 1/8-, and 1/16-strength Japan Yamazaki nutrient solutions) in a completely randomized design. The results indicated that some agricultural characteristics of the tomato seedlings such as the plant height, stem thickness, total dry and fresh weights of the leaves, stems and roots, the G value (G value = total plant dry weight/seedling age),and the seedling vigor index (seedling vigor index = stem thickness/(plant height × total plant dry weight) increased with the elevated CO2, and the increases were strongly dependent on the nutrient solution concentrations, being greater with higher nutrient solution concentrations. The elevated CO2 did not alter the ratio of root to shoot. The total N, P, K, and C absorbed from all the solutions except P in the 1/8- and 1/16-strength nutrient solutions increased in the elevated CO2 treatment. These results demonstrate that the nutrient demands of the tomato seedlings increased at elevated CO2 concentrations.

  11. Influences of excessive Cu on photosynthesis and growth in ectomycorrhizal Pinus sylvestris seedlings

    Institute of Scientific and Technical Information of China (English)

    HUANG Yi; TAO Shu

    2004-01-01

    Growth and photosynthesis responses were measured for Scots pine(Pinus sylvestris L. cv.) inoculated with ectomycorrhizal fungi(Suillus bovinus) under 6.5 and 25 mg/L Cu treatments to evaluate ectomycorrhizal seedlings' tolerance to heavy metal stress. Results showed that excessive Cu can significantly impair the growth and photosynthesis of pine seedlings, but such impairment is much smaller to the ectomycorrhizal seedlings. Under 25 mg/L Cu treatment, the dry weight of ectomycorrhizal seedlings is 25% lower than the control in contrary to 53% of the non-mycorrhizal seedlings, and the fresh weight of ectomycorrhizal roots was significantly higher than those of non-mycorrhizal roots, about 25% and 42% higher at 6.5 and 25 mg/L Cu treatments respectively. Furthermore, ectomycorrhizal fungi induced remarkable difference in the growth rate and pigment content of seedlings under excessive Cu stress. At 25 mg/L Cu, the contents of total chlorophyll, chlorophyll-a and chlorophyll-b were 30% higher in ectomycorrhizal plants than those in non-mycorrhizal plants. O2 evolution and electron transport of PSI and PSII were restrained by elevated Cu stress. However, no significant improvement was observed in reducing the physiological restraining in ectomycorrhizal seedlings over the non-mycorrhizal ones.

  12. Effects of seed mass on seedling success in Artocarpus heterophyllus L., a tropical tree species of north-east India

    Science.gov (United States)

    Khan, M. L.

    2004-03-01

    I examined the effects of seed mass on performance of seedlings of Artocarpus heterophyllus L. (Moraceae), a large evergreen late successional shade-tolerant tree species in three contrasting light conditions. Seed mass varied many fold from 1.5 to 14 g in A. heterophyllus. Germination and germination time showed a significant correlation with seed mass. Germination differed significantly among three light regimes (50%, 25% and 3%). Seed mass and light level significantly affected seedling survival. The seedlings that emerged from large seeds survived better than those from small seeds under all light regimes. Survival of seedlings was maximum in 25% light regime for all seed mass classes but did not differ significantly from that at 50% light regime. Survival was significantly lower in 3% light as compared to 50% and 25% light regimes. Seedling vigor (expressed in terms of seedling height, leaf area and dry weight) was also significantly affected by seed mass and light regimes. Seedlings that emerged from larger seeds and grew under 50% light regime produced the heaviest seedlings, while those resulting from smaller seeds and grown under 3% light regime produced the lightest seedlings. Resprouting capacity of seedlings after clipping was significantly affected by seed mass and light regime. Seedlings emerging from larger seeds were capable of resprouting several times successively. Resprouting was more pronounced under 50% and 25% light regimes as compared to 3% light. Success of A. heterophyllus regeneration appears to be regulated by an interactive effect of seed mass and light regime.

  13. Effects of copper on chlorophyll, proline, protein and abscisic acid level of sunflower (Helianthus annuus L.) seedlings.

    Science.gov (United States)

    Zengin, Fikriye Kirbag; Kirbag, Sevda

    2007-07-01

    The effect of copperchloride (CuCl2) on the level of chlorophyll (a+b), proline, protein and abscisic acid in sunflower (Helianthus annuus L.) seedlings were investigated Control and copper treated (0.4, 0.5 and 0.6 mM) seedlings were grown for ten days in Hoagland solution. Abscisic acid content was determined in root, shoot and leaf tissues of seedlings by HPLC. Copper stress caused significant increase of the abscisic acid contents in roots, shoots and leaves of seedlings. The increase was dependent on the copper salt concentration. Enhanced accumulation of proline in the leaves of seedlings exposed to copper was determined, as well as a decrease of chlorophyll (a+b) and total protein (p Helianthus annuus L.) seedlings. Thus, we assumed that copper levels increase above some critical points seedling growth get negative effects. This assumption is in line with previous findings.

  14. Exogenous calcium induces tolerance to atrazine stress in Pennisetum seedlings and promotes photosynthetic activity, antioxidant enzymes and psbA gene transcripts.

    Science.gov (United States)

    Erinle, Kehinde Olajide; Jiang, Zhao; Ma, Bingbing; Li, Jinmei; Chen, Yukun; Ur-Rehman, Khalil; Shahla, Andleeb; Zhang, Ying

    2016-10-01

    Calcium (Ca) has been reported to lessen oxidative damages in plants by upregulating the activities of antioxidant enzymes. However, atrazine mediated reactive oxygen species (ROS) reduction by Ca is limited. This study therefore investigated the effect of exogenously applied Ca on ROS, antioxidants activity and gene transcripts, the D1 protein (psbA gene), and chlorophyll contents in Pennisetum seedlings pre-treated with atrazine. Atrazine toxicity increased ROS production and enzyme activities (ascorbate peroxidase APX, peroxidase POD, Superoxide dismutase SOD, glutathione-S-transferase GST); but decreased antioxidants (APX, POD, and Cu/Zn SOD) and psbA gene transcripts. Atrazine also decreased the chlorophyll contents, but increased chlorophyll (a/b) ratio. Contrarily, Ca application to atrazine pre-treated seedlings lowered the harmful effects of atrazine by reducing ROS levels, but enhancing the accumulation of total chlorophyll contents. Ca-protected seedlings in the presence of atrazine manifested reduced APX and POD activity, whereas SOD and GST activity was further increased with Ca application. Antioxidant gene transcripts that were down-regulated by atrazine toxicity were up-regulated with the application of Ca. Calcium application also resulted in up-regulation of the D1 protein. In conclusion, ability of calcium to reverse atrazine-induced oxidative damage and calcium regulatory role on GST in Pennisetum was presented. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. Seedling-herbivore interactions: insights into plant defence and regeneration patterns.

    Science.gov (United States)

    Barton, Kasey E; Hanley, Mick E

    2013-08-01

    Herbivores have the power to shape plant evolutionary trajectories, influence the structure and function of vegetation, devastate entire crops, or halt the spread of invasive weeds, and as a consequence, research into plant-herbivore interactions is pivotal to our understanding of plant ecology and evolution. However, the causes and consequences of seedling herbivory have received remarkably little attention, despite the fact that plants tend to be most susceptible to herbivory during establishment, and this damage can alter community composition and structure. In this Viewpoint article we review why herbivory during early plant ontogeny is important and in so doing introduce an Annals of Botany Special Issue that draws together the latest work on the topic. In a synthesis of the existing literature and a collection of new studies, we examine several linked issues. These include the development and expression of seedling defences and patterns of selection by herbivores, and how seedling selection affects plant establishment and community structure. We then examine how disruption of the seedling-herbivore interaction might affect normal patterns of plant community establishment and discuss how an understanding of patterns of seedling herbivory can aid our attempts to restore semi-natural vegetation. We finish by outlining a number of areas where more research is required. These include a need for a deeper consideration of how endogenous and exogenous factors determine investment in seedling defence, particularly for the very youngest plants, and a better understanding of the phylogenetic and biogeographical patterns of seedling defence. There is also much still be to be done on the mechanisms of seedling selection by herbivores, particularly with respect to the possible involvement of volatile cues. These inter-related issues together inform our understanding of how seedling herbivory affects plant regeneration at a time when anthropogenic change is likely to

  16. Ecophysiology of seedlings of three Mediterranean pine species in contrasting light regimes.

    Science.gov (United States)

    Awada, Tala; Radoglou, Kalliopi; Fotelli, Mariangela N; Constantinidou, Helen I A

    2003-01-01

    Seasonal dynamics of net photosynthesis (Anet) in 2-year-old seedlings of Pinus brutia Ten., Pinus pinea L. and Pinus pinaster Ait. were investigated. Seedlings were grown in the field in two light regimes: sun (ambient light) and shade (25% of photosynthetically active radiation (PAR)). Repeated measures analyses over a 12-month period showed that Anet varied significantly among species and from season to season. Maximum Anet in sun-acclimated seedlings was low in winter (yet remained positive) and peaked during summer. Maximum Anet was observed in June in P. pinea (12 micromol m-2 s-1), July in P. pinaster (23 micromol m-2 s-1) and August in P. brutia (20 micromol m-2 s-1). Photosynthetic light response curves saturated at a PAR of 200-300 micromol m-2 s-1 in winter and in shade-acclimated seedlings in summer. Net photosynthesis in sun-acclimated seedlings did not saturate at PAR up to 1900 micromol m-2 s-1 in P. brutia and P. pinaster. Minimum air temperature of the preceding night was apparently one of the main factors controlling Anet during the day. In shade-acclimated seedlings, photosynthetic rates were reduced by 50% in P. brutia and P. pinaster and by 20% in P. pinea compared with those in sun-acclimated seedlings. Stomatal conductance was generally lower in shaded seedlings than in seedlings grown in the sun, except on days with a high vapor pressure deficit. Total chlorophyll concentration per unit leaf area, specific leaf area (SLA) and height significantly increased in P. pinea in response to shade, but not in P. pinaster or P. brutia. In response to shade, P. brutia showed a significant increase in total chlorophyll concentration but not SLA. Photosynthetic and growth data indicate that P. pinaster and P. brutia are more light-demanding than P. pinea.

  17. Identification of 'Ubá' mango tree zygotic and nucellar seedlings using ISSR markers

    Directory of Open Access Journals (Sweden)

    Aline Rocha

    2014-10-01

    Full Text Available Polyembryonic seeds are characterized by the development of over one embryo in the same seed, which can be zygotic and nucellar. The objective of this work was to identify the genetic origin, whether zygotic or nucellar, of seedlings of polyembryonic seeds of 'Ubá' mango tree using ISSR markers, and relating them with the vigor of the seedlings. Thus, mangos were harvested in Visconde do Rio Branco (accession 102 and Ubá (accessions 112, 138, 152 and 159, whose seeds were germinated in plastic trays filled with washed sand. Fifty days after sowing, seedlings from five seeds of each one of the accessions 102, 112, 138, 159 and from 10 seeds of the accession 152, were analyzed. These sseedlings were characterized and evaluated for plant height, stem circumference and mass of fresh aerial part and the most vigorous seedling was the one displaying at least two of these traits higher than the other seedlings from seed. Leaves were collected for genomic DNA extraction, which was amplified using seven ISSR primers previously selected based on the amplification profile and considering the number and resolution of fragments. Zygotic seedlings were found in 18 seeds, which were the most vigorous in six seeds. The results evidenced the existence of genetic variability in orchards using seedlings grown from seeds, because the farmer usually uses the most vigorous ones, assuming that this is of nucellar origin. These results also indicate that the most vigorous seedling are not always nucellar, inasmuch as of 20% of the total seeds evaluated, the zygotic seedling was the most vigorous.

  18. Adaptive Responses of Birch-Leaved Pear (Pyrus betulaefolia Seedlings to Salinity Stress

    Directory of Open Access Journals (Sweden)

    Qiang Sheng WU

    2009-06-01

    Full Text Available One-year-old birch-leaved pear (Pyrus betulaefolia Bunge seedlings were subjected to 0, 50, 100, 150, and 200 mmol/L NaCl solutions for 27 days in order to study the effects of salinity stress on photosynthesis, ion accumulation and enzymatic and non-enzymatic scavenging of reactive oxygen species in the seedlings. The research was performed in a greenhouse using potted trees. Salinity stress reduced photosynthetic rates, stomatal conductance and water use efficiency of leaves of the pear seedlings, but increased transpiration rates and leaf temperature. Hydrogen peroxide and superoxide anion radical contents increased with increasing NaCl concentrations, a phenomena also observed for malondialdehyde, suggesting that leaves of the pear seedlings suffered from oxidative injury. Superoxide dismutase (SOD and catalase (CAT activities quickly responded by increasing when the pear seedlings were subjected to salinity stress. Total protein content in leaves of the seedlings was restrained by salinity stress, whereas ascorbate content increased. Salinity stress reduced glutathione content once the birch-leaved pear seedlings were exposed to a low level (50 or 100 mmol/L of NaCl, whereas a high level (150 or 200 mmol/L NaCl of salinity stress stimulated the accumulation of glutathione. Salinity stress increased the accumulation of Na+, Cl-, K+ and Mg2+ in the seedlings, but reduced Ca2+ levels and the ratio of other ions to Na+ except K+/Na+ under 50 mmol/L NaCl conditions. This suggests that leaves of birch-leaved pear seedlings possess the capacity for salt exclusion only under 50 mmol/L NaCl conditions, and Ca2+ does not play a fundamental role as a secondary messenger under salinity stress conditions.

  19. The Diagnosis of Components Information Distribution of Wheat Seedlings Based on the Hyperspectral Imaging

    Directory of Open Access Journals (Sweden)

    Qiong Wu

    2012-08-01

    Full Text Available It is adopted mostly of the non-imaging spectrometer in current crop seedling monitoring, this method is greatly interfered by the soil background, makes it difficult to analyze the partial area nutritional status of the seedlings. In this study, we took advantage of merging the image with spectrum of the imaging spectrometer, to analyze the canopy, individuals, different size of leaves, characteristics of different regions of the wheat seedlings under the condition of salt stress, to diagnose the distribution of its chlorophyll composition information. We collected the imaging spectrum of 126 wheat samples in the wavelength range of 400 ~1000 nm, selected the average spectrum, exerted Correlation Analysis on the spectrum of wheat seedlings with the SPAD value, It could be seen that the biggest absolute value of the correlation coefficient was at 693 nm, which was considered as the characteristics wavelength of wheat seedlings. To establish the linear regression model using this wavelength and substituted 1the reflectance data of each point into the model, then we got the SPAD value of each point, to form the relative content distribution map of chlorophyll, whereby to diagnose the distribution of seedlings component. The results showed that: Hyper spectral imaging could reflect the reflectance differences of wheat seedlings under different salt stress treatments, through extracting the spectral reflectance curve leaves of single wheat seedlings in different parts of the different leaves and single leaf base, the midst of leaves and tip in the plant, from the results of filling map we could intuitively see the leaves’ chlorophyll distribution in different parts. It indicated that hyper spectral imaging can characterize the seedlings situation of different plants, also could characterize the characteristics of different district of leaves. The results indicated that hyper spectral imaging were suitable for the non-invasive detection of

  20. Germination requirements and seedling responses to water availability and soil type in four eucalypt species

    Science.gov (United States)

    Schütz, Wolfgang; Milberg, Per; Lamont, Byron B.

    2002-03-01

    We conducted experiments on seed germination, seedling survival and seedling growth of four Eucalyptus species to identify factors that might explain why they are restricted to the two major soil types in southwestern Australia, deep sands ( E. macrocarpa, E. tetragona) and lateritic loam ( E. loxophleba, E. wandoo). At high temperatures (28 °C), germination in darkness was lower for the two 'loam species' than for the 'sand species', while there were no differences in light or at low temperatures (10 °C). Germination commenced earlier, and was faster in the sand species than in the loam species, but was almost inhibited in all species by -1.0 MPa. E. tetragona proved the most drought-tolerant in terms of germination level and seedling survival. Seedlings of the sand species had much longer roots two weeks after germination in the absence of water stress, and the roots of more seedlings continued to elongate under moderate water stress (-1.0 MPa), than the two loam species. Roots were longer in all species, except E. macrocarpa, at -0.5 MPa than at -0.1 MPa, despite seedlings having a smaller mass and hypocotyl length. As water availability declined, there was a tendency for the sand species to survive longer on sand than on loam while soil type had no effect on the loam species. Pattern and duration of seedling survival of the loam species was similar to that of the sand species despite their smaller seeds. We conclude that seedlings from the large-seeded sand species are able to penetrate the soil profile faster and deeper, but that they are not less prone to drying soils than seedlings from the small-seeded loam species. Instead, seed size and germination speed are important prerequisites to cope successfully with unstable soil surfaces and to exploit the rapidly descending water in deep sands.

  1. Seedling Regeneration in the Alpine Treeline Ecotone: Comparison of Wood Microsites and Adjacent Soil Substrates

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    Adelaide Chapman Johnson

    2016-11-01

    Full Text Available Although climate warming is generally expected to facilitate upward advance of forests, conifer seedling regeneration and survival may be hindered by low substrate moisture, high radiation, and both low and high snow accumulation. To better understand substrate-related factors promoting regeneration in the alpine treeline ecotone, this study compared 2 substrates supporting conifer seedlings: rotten downed wood and adjacent soil. Study locations, each with 3 levels of incoming radiation, were randomly selected at forest line–alpine meadow borders in Pacific Northwest wilderness areas extending along an east–west precipitation gradient. Associations among substrate type, seedling density, radiation, site moisture, site temperature, plant water potential, and plant stomatal conductance were assessed. Wood microsites, flush with the ground and supporting Abies spp conifer seedlings, extended up to 20 m into alpine meadows from the forest line. Although wood microsites thawed later in the spring and froze earlier in the fall, they had warmer summer temperatures, greater volumetric water content, and more growing degree hours, and seedlings growing on wood had higher water potentials than seedlings growing on adjacent soil. At drier eastern sites, there was a positive relationship between seedling density and volumetric water content. Further, there was a positive relationship between seedling stomatal conductance and volumetric water content. Our study indicates that in the Pacific Northwest. and likely elsewhere, seedlings benefit from wood microsites, which provide greater water content. Given predictions of increased summer drought in some locations globally, wood microsites at forest line–alpine meadows and forest line–grasslands borders may become increasingly important for successful conifer regeneration.

  2. Spatial variation in tree seedling density after the site preparation for planting in a cleared coniferous plantation in Hokkaido, northern Japan

    OpenAIRE

    Shin, ChangSeob; Shibuya, Masato

    2007-01-01

    To study spatial variation in natural tree seedling density and the relationship between variation in seedling density and seed dispersal mode at a cleared site, we surveyed natural tree seedlings after the site preparation for planting in a coniferous plantation cleared by a typhoon disturbance in 2004. The site was located near Sikotsuko Lake, Hokkaido, northern Japan. Twenty-five tree seedling species were found and the mean seedling density was 9.8 seedlings/m2. Seedlings of non-animal-di...

  3. Nutrient utilization in some tropical forest tree seedlings

    Energy Technology Data Exchange (ETDEWEB)

    Lalman, M.A.

    1985-01-01

    The concentration of N, P, K, Ca and Na in seedlings of Dalbergia sissoo, Tamarindus indica, Diospyros melanoxylon, Terminalia arjuna and Tectona grandis was evaluated in field plantings in Uttar Pradesh, from the age of 1 to 12 months (April 1978 to March 1979). In all species, concentration of Na in leaves was higher than that of K, Ca and P (highest in D. melanoxylon) and was higher in leaves than in roots and stems. Concentration was found to increase with age of leaves up to 8-9 months (at the time of yellowing), after which N, P and K contents decreased rapidly. N, P and K content of stems and roots showed steady increase with age, but Ca and Na, after showing increases up to 8-10 months showed a slight reduction in the 11th and 12th months. 51 references.

  4. Tillers induction in Bactris gasipaes var. gasipaes seedlings

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    Ernani Augusto Ochekoski Mossanek

    2014-04-01

    Full Text Available Bactris gasipaes produces heart-of-palm. Peach palm is a perennial crop that has a tillering capacity, being an alternative to illegal extraction. There is a lack of studies about vegetative propagation technics for this species. The present study aimed to analyze different tillering induction methods in Bactris gasipaes var. gasipaes seedlings in four different seasons. The treatments were: 1 stem bending; 2 stem bending and application of 150 mg kg-1 of benzylaminopurine; 3 stem bending and application of 150 mg kg-1 of gibberellic acid and; 4 stem girdling. The experimental design was random with 4 replicates of 20 plants per treatment. Anatomical analyses were conducted at the stem, and the tillering and mortality of the treated plants were evaluated. It was possible to identify the stem tissues and the meristematic apex site by anatomical analysis. The stem bending treatments were inefficient; but girdling presented potential as tillers inducer.

  5. Measurement of seedling growth rate by machine vision

    Science.gov (United States)

    Howarth, M. Scott; Stanwood, Phillip C.

    1993-05-01

    Seed vigor and germination tests have traditionally been used to determine deterioration of seed samples. Vigor tests describe the seed potential to emerge and produce a mature crop under certain field conditions and one measure is seedling growth rate. A machine vision system was developed to measure root growth rate over the entire germination period. The machine vision measurement technique was compared to the manual growth rate technique. The vision system provided similar growth rate measurements as compared to the manual growth rate technique. The average error between the system and a manual measurement was -0.13 for the lettuce test and -0.07 for the sorghum test. This technique also provided an accurate representation of the growth rate as well as percent germination.

  6. Correlations between polyamine ratios and growth patterns in seedling roots

    Science.gov (United States)

    Shen, H. J.; Galston, A. W.

    1985-01-01

    The levels of putrescine, cadaverine, spermidine and spermine were determined in seedling roots of pea, tomato, millet and corn, as well as in corn coleoptiles and pea internodes. In all roots, putrescine content increased as elongation progressed, and the putrescine/spermine ratio closely paralleled the sigmoid growth curve up until the time of lateral root initiation. Spermidine and spermine were most abundant near the apices and declined progressively with increasing age of the cells. In the zone of differentiation of root hairs in pea roots, putrescine rose progressively with increasing age, while cadaverine declined. In both pea internodes and corn coleoptiles, the putrescine/spermidine ratio rises with increasing age and elongation. Thus, a block in the conversion of the diamine putrescine to the triamine spermidine may be an important step in the change from cell division to cell elongation.

  7. Seedling test and genetic analysis of white poplar hybrid clones

    Institute of Scientific and Technical Information of China (English)

    LI Bo; JIANG Xi-bing; ZHANG You-hui; ZHANG Zhi-yi; LI Shan-wen; AN Xin-min

    2008-01-01

    Cross breeding strategies are very efficient for gaining new and superior genotypes. Ninety-eight new white poplar hybrid clones produced from 12 cross combinations within the Section Leuce Duby were studied using genetic analysis and seedling tests. We exploited the wide variation that exists in this population and found that the differences among diameter at breast height (DBH), root collar diameter (RCD) and height (H) were statistically extremely significant. The repeatability of clones of these measured traits ranged from 0.947-0.967, which indicated that these Waits were strongly controlled by genetic factors. Based on multiple comparisons, a total of 25 clones showed better performance in growth than the conlrol cultivar. These 25 clones were from six different cross combinations, which can guarantee a larger genetic background for future new clone promotion projects. This study provides a simple overview on these clones and can guide us to carry out subsequent selection plans.

  8. Development of an automatic visual grading system for grafting seedlings

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    Subo Tian

    2017-01-01

    Full Text Available In this study, a visual grading system of vegetable grafting machine was developed. The study described key technology of visual grading system of vegetable grafting machine. First, the contrasting experiment was conducted between acquired images under blue background light and natural light conditions, with the blue background light chosen as lighting source. The Visual C++ platform with open-source computer vision library (Open CV was used for the image processing. Subsequently, maximum frequency of total number of 0-valued pixels was predicted and used to extract the measurements of scion and rootstock stem diameters. Finally, the developed integrated visual grading system was experimented with 100 scions and rootstock seedlings. The results showed that success rate of grading reached up to 98%. This shows that selection and grading of scion and rootstock could be fully automated with this developed visual grading system. Hence, this technology would be greatly helpful for improving the grading accuracy and efficiency.

  9. Vegetation management for reducing mortality of ponderosa pine seedlings from Thomomys spp

    Science.gov (United States)

    Barnes, V.G.; Anthony, M.; ,

    1995-01-01

    The effects of vegetation management on Mazama pocket gopher activity and damage to ponderosa pine seedlings were studied using atrazine herbicide to alter the habitat. Atrazine treatments were applied to a large treatment unit and observed effects were compared to an untreated control unit. The greatly reduced forb and grass cover on the treated unit was associated with a corresponding decrease in pocket gopher activity. Times until seedlings first incurred gopher damage and overall survival of two cohorts of seedlings were greatly increased on the treated unit.

  10. Effects of different substrates on basil seedlings quality (Ocimum basilicum L.

    Directory of Open Access Journals (Sweden)

    Jelačić Slavica

    2005-01-01

    Full Text Available In this study five different substrates were used, such as: compost; mixture of compost, Lumbrikus H and garden soil; mixture of compost and Lumbrikus H; mixture of compost, Lumbrikus H and peat Galicina and Seedling Klassman substrate. Basil seedling was produced in containers according to "speeding" system. The studies have shown that the best quality of basil seedling of varieties Genovese and Lattuga is achieved when the mixture of substrates Compost, Lumbrikus H and Galicina peat are applied in the volume proportion of 50% : 30% : 20%.

  11. Response of seedlings growth of Pinus sylvestriformis to atmospheric CO2 enrichment in Changbai Mountain

    Institute of Scientific and Technical Information of China (English)

    Han S hijie; Wang Chen rui; Zhang Junhui; Zou Chunjing; Zhou Yumei; Wang Xiaochun

    1999-01-01

    The biomass and ratio of root-shoot of Pinus sylvestriformis seedlings at CO2 concentration of 700 μL· L-1 and 500 μL· L-1 were measured using open-top chambers (OTCs) in Changbai Mountain during Jun.to Oct. in 1999. The results showed that doubling CO2 concentration was benefit to seedling growth of the species (500 μL· L-1 was better than 700 μL-L-1 ) and the biomass production was increased in both aboveground and underground parts of seedlings. Carbon transformation to roots was evident as rising of CO2 concentration.

  12. [Effects of seed coating formulation on seedling characters of Atractylodes macrocephala].

    Science.gov (United States)

    Yu, X; Sheng, S; Wang, Z; Xu, J; Yao, J; Shao, M

    2001-09-01

    The effects of seed coating formulation (SCF) of Atractylodes macrocephala Koidz. on seedling in two experimental plots located in Hangzhou and Jiande were studied, and desinged with L9(3(4)) orthogonal comparison. The results showed that the SCF with paclobutrazol (pp333) had a significant effect on the rate of germination at Hangzhou plot, all factors had no significant effects on length of seedlings in both plots, and both atonik (sodium O-nitrophenolate) and PP333 on the fresh or dry seedling weight had significant effects.

  13. Effects of Different Quantities of Tea-leaf Wormcast Substrate on the Growth of Tomato Seedling

    OpenAIRE

    Yang, Wei; Hu, Feng; Wang, Dong-sheng; LIU Man-qiang; Li, Hui-Xin; HUANG Zhong-yang; Chang, Yi-Jun; JIAO Jia-guo

    2015-01-01

    The tomato seedling experiment was conducted to investigate the effect of substrate on the tomato seedling growth from five proportions of tea-leaf wormcast to peat, perlite and vermiculite, namely treatment I(1:5:2:2), treatment Ⅱ(2:4:2:2), treatment Ⅲ(3:3:2:2), treatment Ⅳ(4:2:2:2), treatment Ⅴ(6:0:2:2), respectively. The botany properties and characters of tomato seedling were observed to discuss the application effect of tea-leaf wormcast substrate. The results showed that in all treatmen...

  14. Responses of fractal dimensions of Picea koraiensis seedlings to different light environments

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The changes of fractal dimension of Picea koraiensis seedlings under different light intensities in natural secondary forests was studied. The results showed that with the change of light environment, crown characters of Picea koraiensis seedlings exhibited a greater plastic in lateral number, lateral increment, lateral dry weight, and specific leaf area. The range of calculated fractal dimensions of seedling crowns was confined between 2.5728 and 2.1036, but maximum of fractal dimension achieved in term moderate shading and in extreme low light conditions fractal dimension was least.

  15. Effect of La3+ on Activities of Antioxidant Enzymes in Wheat Seedlings under Mercury Stress

    Institute of Scientific and Technical Information of China (English)

    庞欣; 王东红; 彭安; 张福锁; 邢晓燕; 李春俭

    2002-01-01

    The effects of La(NO3)3 on the growth,activities of SOD,CAT and MDA content in shoots and roots of wheat seedlings under mercury stress were evaluated by the nutrient solution culture experiment. The results suggest that there is positive effect of La(NO3)3 on enhancing the activities of SOD,CAT,decrease of MDA content in shoots and roots of wheat seedlings during 0~5 d. But La(NO3)3 evens and cooperates with mercury when plants are too long under mercury stress. Mercury inhibits the growth of wheat seedlings more grievously.

  16. Phenylalanine is required to promote specific developmental responses and prevents cellular damage in response to ultraviolet light in soybean (Glycine max during the seed-to-seedling transition.

    Directory of Open Access Journals (Sweden)

    Joe H Sullivan

    Full Text Available UV-radiation elicits a suite of developmental (photomorphogenic and protective responses in plants, but responses early post-germination have received little attention, particularly in intensively bred plants of economic importance. We examined germination, hypocotyl elongation, leaf pubescence and subcellular responses of germinating and/or etiolated soybean (Glycine max (L. Merr. seedlings in response to treatment with discrete wavelengths of UV-A or UV-B radiation. We demonstrate differential responses of germinating/young soybean seedlings to a range of UV wavelengths that indicate unique signal transduction mechanisms regulate UV-initiated responses. We have investigated how phenylalanine, a key substrate in the phenylpropanoid pathway, may be involved in these responses. Pubescence may be a key location for phenylalanine-derived protective compounds, as UV-B irradiation increased pubescence and accumulation of UV-absorbing compounds within primary leaf pubescence, visualized by microscopy and absorbance spectra. Mass spectrometry analysis of pubescence indicated that sinapic esters accumulate in the UV-irradiated hairs compared to unirradiated primary leaf tissue. Deleterious effects of some UV-B wavelengths on germination and seedling responses were reduced or entirely prevented by inclusion of phenylalanine in the growth media. Key effects of phenylalanine were not duplicated by tyrosine or tryptophan or sucrose, nor is the specificity of response due to the absorbance of phenylalanine itself. These results suggest that in the seed-to-seedling transition, phenylalanine may be a limiting factor in the development of initial mechanisms of UV protection in the developing leaf.

  17. Interaction between hydrotropism and gravitropism in seedling roots

    Science.gov (United States)

    Kobayashi, A.; Takahashi, A.; Yamazaki, Y.; Kakimoto, Y.; Higashitani, A.; Fujii, N.; Takahashi, H.

    Roots display positive hydrotropism in response to a moisture gradient, which could play a role in avoiding drought stress. Because roots also respond to other stimuli such as gravity, touch and light and exhibit gravitropism, thigmotropism and phototropism, respectively, their growth orientation is determined by interaction among those tropisms. We have demonstrated the interaction between hydrotropism and gravitropism. For example, 1) agravitropic roots of pea mutant strongly respond to a moisture gradient and show positive hydrotropism by overcoming gravitropism, 2) in wild type pea roots hydrotropism is weak but pronounced when rotated on clinostat, 3) cucumber roots are positively gravitropic on the ground but become hydrotropic in microgravity, and 4) maize roots change their growth direction depending on the intensities of both gravistimulation and hydrostimulation. Here we found that Arabidopsis roots could display strong hydrotropism by overcoming gravitropism. It was discovered that amyloplasts in the columella cells are rapidly degraded upon exposure to a moisture gradient. Thus, degradation of amyloplasts could reduce the responsiveness to gravity, which could pronounce the hydrotropic response. In hydrotropically stimulated roots of pea seedlings, however, we could not observe a rapid degradation of amyloplasts in the columella cells. These results suggest that mechanism underlying the interaction between hydrotropism and gravitropism differs among plant species. To further study the molecular mechanism of hydrotropism and its interaction with gravitropism, we isolated unique mutants of Arabidopsis of which roots showed either ahydrotropism, reduced hydrotropism or negative hydrotropic response and examined their gravitropism, phototropism, waving response, amyloplast degradation and elongation growth. Based on the characterization of hydrotropic mutants, we will attempt to compare the mechanisms of the two tropisms and to clarify their cross talk for

  18. Tolerance of wheat varieties seedlings by glyphosate accelerated degradation

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    Jerković Zoran

    2014-01-01

    Full Text Available Lengths of seedlings aboveground parts of nine wheat varieties grown in greenhouse were reduced by 4-20%. They were tested during April at around 20oC after twice daily treatments with glyphosate based herbicide (0.5 ml in 1l water solution, 0.5 dl on 0.5 m2. When results of permanent artificially and daily lighted trials were compared, four groups of varieties were recognized same as was when near isogenic lines containing different leaf rust resistance genes (Lr NILs were focused in winter. Growth of variety Pobeda decreased more when seedlings were not permanent lighted which confirmed the common herbicide effect. Tolerance of other varieties was again explained by enzymatic degradation of glyphosate and chlorophyll inhibition by consequential phosphorus acids. Varieties Simonida, Tavita and Rapsodia were similar by reaction to glyphosate as Lr 1 and Lr 21 NILs. NS 40S contained Lr 3a with increased hydrolytic stability compared to Lr 24 but able to cleave external single phosphorus for the difference of Lr 19 or Lr 29. Their final effect was similar to previous stated of Lr 15 NIL during the winter. Varieties Gora and Metka had gene Lr 19, Enigma Lr 29 while Ilina Lr 24. Focusing herbicide residua transfer in seed probability, accounting optimal time for recovering ability of chlorophyll and temporary higher temperatures necessary for Lr genes even parasite free activity the varieties Gora, Metka and Enigma appeared to be possible solution for glyphosate apply near wheat heading in semiarid regions.

  19. Amelioration of arsenic toxicity by phosphate salts in mungbean seedlings.

    Science.gov (United States)

    Swarnakar, Arpita; Mukherji, Subhendu

    2005-07-01

    Sodium arsenate (Na2HAsO4.7H2O) is a potent inhibitor of mungbean seed germination and seedling growth. Germination is totally stopped at or above 50 microM Na2HAsO4.7H2O. Inhibition of seedling elongation started at a lower concentration of 5 microM As(V) and was drastically reduced at 20 microM As(V). Nutrients like salts of macroelements viz., NaH2PO4.2H2O, KH2PO4, K2SO4, MgSO4.7H2O, CaCl2.2H2O, (NH4)2SO4 NH4NO3 solutions at a concentration of 10mM and microelements viz., ZnSO4, CuSO4.5H2O, Na2MoO4.2H2O, MnCl2.4H2O, CoCl2.6H2O, FeSO4.7H2O solutions at a concentration of 1mM could help to ameliorate the toxic effects of As(V) to different degrees. Amelioration of As(V) toxicity was possible only when the mungbean seeds were pretreated with the above mentioned nutrients for 24 hr and then transferred to sodium arsenate. Simultaneous treatment of nutrients with As(V) or using nutrient solutions following As(V) treatment were of no help to reverse the toxic effects of sodium arsenate.

  20. High compatibility between arbuscular mycorrhizal fungal communities and seedlings of different land use types in a tropical dry ecosystem.

    Science.gov (United States)

    Gavito, Mayra E; Pérez-Castillo, Daniel; González-Monterrubio, César F; Vieyra-Hernández, Teresa; Martínez-Trujillo, Miguel

    2008-12-01

    We conducted this study to explore limitations for the establishment of mycorrhizal associations in disturbed areas of the tropical dry ecosystem in the Chamela region of Jalisco, Mexico. Specifically, we: (1) assessed the diversity and composition of arbuscular mycorrhizal fungal (AMF) communities through spore morphospecies identification in three common land uses (primary forest, secondary forest, and pasture), (2) tested the inoculum potential of the AMF communities and the effect of water stress on the establishment of mycorrhizal associations in seedlings of various plant species, and (3) explored the importance of AMF community composition on early seedling development. Soil and root samples were taken from 15 random points in each of three plots established in two primary forests, two 26-year-old secondary forests, and two 26-year-old pastures. We expected that because of soil degradation and management, pastures would have the lowest and primary forests the highest AMF species richness. We found evidence for changes in AMF species composition due to land use and for higher morphospecies richness in primary forests than in secondary forests and pastures. We expected also that water stress limited plant and mycorrhizal development and that plants and AMF communities from secondary forests and pastures would be less affected by (better adapted to) water stress than those from the primary forest. We found that although all plant species showed biomass reductions under water stress, only some of the plant species had lower mycorrhizal development under water stress, and this was regardless of the AMF community inoculated. The third hypothesis was that plant species common to all land use types would respond similarly to all AMF communities, whereas plant species found mainly in one land use type would grow better when inoculated with the AMF community of that specific land use type. All plant species were however equally responsive to the three AMF communities

  1. Hylastes ater (Curculionidae: Scolytinae Affecting Pinus radiata Seedling Establishment in New Zealand

    Directory of Open Access Journals (Sweden)

    Stephen D. Reay

    2012-01-01

    Full Text Available The introduced pine bark beetle Hylastes ater has been present in New Zealand for around 100 years. The beetle has been a minor pest on pines. Research was undertaken to control the pest in the 1950s–1970s, with a biological control agent introduced with limited success. Following a reasonably long period with minimal research attention, renewed interest in developing a better understanding of the pest status was initiated in the mid to late 1990s. Subsequently, a significant amount of research was undertaken, with a number of studies exploring the role of this pest of exotic forests in New Zealand. These studies ranged from attempting to quantify damage to seedlings, evaluate the role of the beetle in vectoring sapstain fungi, explore options for management, and evaluate the potential for chemical and biological control. From these studies, a number of findings were made that are relevant to the New Zealand exotic forest industry and shed new light onto the role of secondary bark beetles globally.

  2. Growth and mineral nutrition in seedlings of australian cedar (Toona ciliata subjected to nutrient deprivation

    Directory of Open Access Journals (Sweden)

    Bruno da Silva Moretti

    2011-12-01

    Full Text Available In order to evaluate nutritional requirements and the effect of nutrient deprivation on the development of seedlings of Australian cedar (Toona ciliata M. Roem var. australis, a greenhouse experiment was conducted. The substrate used was a dystroferric red latosol with low nutrient availability, using 15 treatments and applying the missing element technique. The experiment included two complete treatments (one provided N, P, K, S, B, Cu, Zn with limestone while another provided N, P, K, Ca, Mg, S, B, Cu and Zn without limestone, besides deprivation of each nutrient (-N, -P, -K, -Ca, -Mg, -S, -B, -Cu and -Zn, one treatment with combined deprivation of B, Cu and Zn, one treatment applying limestone only, one treatment applying N, P, K, S, B, Cu and Zn, without limestone, and one absolute control treatment (natural soil. The following characteristics were evaluated: height, diameter, shoot dry matter and root dry matter, and nutrient content in the shoot dry matter after 150 days. Australian cedar plants have high nutritional requirements, and nutrients P, N, S, Ca, K, Mg and Cu, in that order, were found to be limiting factors to plant development. B and Zn deprivation did not affect plant development. Limestone application was essential for the development of Australian cedar plants. Initial deficiency symptoms were found to be the result of S, limestone and N deprivation.

  3. Regulation of ion homeostasis by aminolevulinic acid in salt-stressed wheat seedlings

    Energy Technology Data Exchange (ETDEWEB)

    Türk, Hülya, E-mail: hulyaa.turk@hotmail.com [Biology Department, Science Faculty, Ataturk University, Erzurum (Turkey); East Anatolian High Technology Research and Application Center, Ataturk University, Erzurum (Turkey); Genişel, Mucip, E-mail: m.genisel@hotmail.com [Department of Crop and Animal Production, Vocational High School, Agri (Turkey); Erdal, Serkan, E-mail: serkanerdal25@hotmail.com [Biology Department, Science Faculty, Ataturk University, Erzurum (Turkey)

    2016-04-18

    Salinity is regarded as a worldwide agricultural threat, as it seriously limits plant development and productivity. Salt stress reduces water uptake in plants by disrupting the osmotic balance of soil solution. In addition, it creates a damaged metabolic process by causing ion imbalance in cells. In this study, we aim to examine the negative effects of 5-aminolevulinic acid (ALA) (20 mg/l) on the ion balance in wheat seedling leaves exposed to salt stress (150 mM). Sodium is known to be highly toxic for plant cells at high concentrations, and is significantly increased by salt stress. However, it can be reduced by combined application of ALA and salt, compared to salt application alone. On the other hand, while the K{sup +}/Na{sup +} ratio was reduced by salt stress, ALA application changed this ratio in favor of K{sup +}. Manganese, iron, and copper were also able to reduce stress. However, ALA pre-treatment resulted in mineral level increments. Conversely, the stress-induced rise in magnesium, potassium, calcium, phosphorus, zinc, and molybdenum were further improved by ALA application. These data clearly show that ALA has an important regulatory effect of ion balance in wheat leaves.

  4. Rapid analysis of neonicotinoid insecticides in guttation drops of corn seedlings obtained from coated seeds.

    Science.gov (United States)

    Tapparo, Andrea; Giorio, Chiara; Marzaro, Matteo; Marton, Daniele; Soldà, Lidia; Girolami, Vincenzo

    2011-06-01

    Regarding the hypothesis that neonicotinoid insecticides used for seed coating of agricultural crops - mainly corn, sunflower and seed rape - are related to the extensive death of honey bees, the phenomenon of corn seedling guttation has been recently considered as a possible route of exposure of bees to these systemic insecticides. In the present study, guttation drops of corn plants obtained from commercial seeds coated with thiamethoxam, clothianidin, imidacloprid and fipronil have been analyzed by an optimized fast UHPLC-DAD procedure showing excellent detection limits and accuracy, both adequate for the purpose. The young plants grown both in pots - in greenhouse - and in open field from coated seeds, produced guttation solutions containing high levels of the neonicotinoid insecticides (up to 346 mg L(-1) for imidacloprid, 102 mg L(-1) for clothianidin and 146 mg L(-1) for thiamethoxam). These concentration levels may represent lethal doses for bees that use guttation drops as a source of water. The neonicotinoid concentrations in guttation drops progressively decrease during the first 10-15 days after the emergence of the plant from the soil. Otherwise fipronil, which is a non-systemic phenylpyrazole insecticide, was never detected into guttation drops. Current results confirm that the physiological fluids of the corn plant can effectively transfer neonicotinoid insecticides from the seed onto the surface of the leaves, where guttation drops may expose bees and other insects to elevated doses of neurotoxic insecticides.

  5. Genetic diversity analysis of rice (Oryza sativa genotypes for seedling characters under saline - alkaline condition

    Directory of Open Access Journals (Sweden)

    K Seetharam, S.Thirumeni, K.Paramasivam, S.Nadaradjan

    2013-03-01

    Full Text Available Rice is life for Asians as it provides 43 per cent calorie requirement for more than 70 per cent of the population. Theproduction is often limited by salinity. Understanding of physiological and genetic mechanisms is necessary for a breedingprogramme to improve crop performance under environmental stresses. Thirty rice genotypes pre-germinated in salinealkalinewater (pH-9.60; EC-10.0; SAR-54.32; RSC- 11.51 were placed in plastic cups filled with sterile soil and the stresswas imposed upto 21 days. Genetic diversity was estimated based on the observations recorded on germination per centage,vigor index, shoot length, root length, seedling length, root/shoot ratio, seeding dry weight, Na+/K+ ratio. The genotypeswere grouped in to five clusters based on the Euclidean coefficient which ranged between 2.09(CSR10 X CSR 13 and76.29 (IWP X Chettiviruppu. Cluster II was largest (22 genotypes followed by cluster I (4 genotypes. Genotypes groupedunder cluster I showed low Na+/K+ ratio which is an important physiological trait for salinity tolerance. Cluster V (MI 48 &IWP grouped the susceptible genotypes which had high Na+/K+ ratio. The hybrids thus developed from the genotypes ofcluster I & V may express high magnitude of transgressive segregants.

  6. A spatially explicit analysis of seedling recruitment in the terrestrial orchid Orchis purpurea.

    Science.gov (United States)

    Jacquemyn, Hans; Brys, Rein; Vandepitte, Katrien; Honnay, Olivier; Roldán-Ruiz, Isabel; Wiegand, Thorsten

    2007-01-01

    Seed dispersal and the subsequent recruitment of new individuals into a population are important processes affecting the population dynamics, genetic diversity and spatial genetic structure of plant populations. Spatial patterns of seedling recruitment were investigated in two populations of the terrestrial orchid Orchis purpurea using both univariate and bivariate point pattern analysis, parentage analysis and seed germination experiments. Both adults and recruits showed a clustered spatial distribution with cluster radii of c. 4-5 m. The parentage analysis resulted in offspring-dispersal distances that were slightly larger than distances obtained from the point pattern analyses. The suitability of microsites for germination differed among sites, with strong constraints in one site and almost no constraints in the other. These results provide a clear and coherent picture of recruitment patterns in a tuberous, perennial orchid. Seed dispersal is limited to a few metres from the mother plant, whereas the availability of suitable germination conditions may vary strongly from one site to the next. Because of a time lag of 3-4 yr between seed dispersal and actual recruitment, and irregular flowering and fruiting patterns of adult plants, interpretation of recruitment patterns using point patterns analyses ideally should take into account the demographic properties of orchid populations.

  7. The effects of lead on the gaseous exchange and photosynthetic carbon metabolism of pea seedlings

    Directory of Open Access Journals (Sweden)

    Jerzy W. Poskuta

    2014-01-01

    Full Text Available Roots of whole 3 week-old pea seedlings (Pisum sativum L. var. "Bordi" were immersed for 24 h in solutions of lead chloride at Pb copcentrations of 200, 400, 800,12000 mg dm3. Accumulation of lead in roots was independent of the Pb concentration, whereas the accumulation of Pb in shoots was an almost linear function of the concentration of this element in the root medium. This treatment caused Pb concentration-dependent inhibition of apparent photosynthesis (APS, photorespiration (PR, 14CO2 uptake, stomatal opening and transpiration of shoots and also germination of seeds. The most sensitive to Pb contamination was CO2 exchange, then transpiration and to a lesser degree germination of seeds. Lead caused a considerable alteration of photosynthetic and photorespiratory carbon metabolism, restricted the 14C-labeling of: phosphoglycerate, ribose+ribulose, sucrose, glycolate and glycine+serine. Under conditions of C02 uptake limited by lead, an enhancement of the 14C-labeling of malate+citrate, alanine and glucose was observed.

  8. Regulation of ion homeostasis by aminolevulinic acid in salt-stressed wheat seedlings

    Science.gov (United States)

    Türk, Hülya; Genişel, Mucip; Erdal, Serkan

    2016-04-01

    Salinity is regarded as a worldwide agricultural threat, as it seriously limits plant development and productivity. Salt stress reduces water uptake in plants by disrupting the osmotic balance of soil solution. In addition, it creates a damaged metabolic process by causing ion imbalance in cells. In this study, we aim to examine the negative effects of 5-aminolevulinic acid (ALA) (20 mg/l) on the ion balance in wheat seedling leaves exposed to salt stress (150 mM). Sodium is known to be highly toxic for plant cells at high concentrations, and is significantly increased by salt stress. However, it can be reduced by combined application of ALA and salt, compared to salt application alone. On the other hand, while the K+/Na+ ratio was reduced by salt stress, ALA application changed this ratio in favor of K+. Manganese, iron, and copper were also able to reduce stress. However, ALA pre-treatment resulted in mineral level increments. Conversely, the stress-induced rise in magnesium, potassium, calcium, phosphorus, zinc, and molybdenum were further improved by ALA application. These data clearly show that ALA has an important regulatory effect of ion balance in wheat leaves.

  9. Transcriptional profiling of Petunia seedlings reveals candidate regulators of the cold stress response

    Directory of Open Access Journals (Sweden)

    Bei eLi

    2015-03-01

    Full Text Available Petunias are important ornamentals with the capacity for cold acclimation. So far, there is limited information concerning gene regulation and signaling pathways related to the cold stress response in petunias. A custom-designed petunia microarray representing 24816 genes was used to perform transcriptome profiling in petunia seedlings subjected to cold at 2°C for 0.5 h, 2 h, 24 h and 5 d. A total of 2071 transcripts displayed differential expression patterns under cold stress, of which 1149 were up-regulated and 922 were down-regulated. Gene ontology enrichment analysis demarcated related biological processes, suggesting a possible link between flavonoid metabolism and plant adaptation to low temperatures. Many novel stress-responsive regulators were revealed, suggesting that diverse regulatory pathways may exist in petunias in addition to the well-characterized CBF pathway. The expression changes of selected genes under cold and other abiotic stress conditions were confirmed by real-time RT-PCR. Furthermore, weighted gene co-expression network analysis divided the petunia genes on the array into 65 modules that showed high co-expression and identified stress-specific hub genes with high connectivity. Our identification of these transcriptional responses and groups of differentially expressed regulators will facilitate the functional dissection of the molecular mechanism in petunias responding to environment stresses and extend our ability to improve cold tolerance in plants.

  10. Protocols for sagebrush seed processing and seedling production at the Lucky Peak Nursery

    Science.gov (United States)

    Clark D. Fleege

    2010-01-01

    This paper presents the production protocols currently practiced at the USDA Forest Service Lucky Peak Nursery (Boise, ID) for seed processing and bareroot and container seedling production for three subspecies of big sagebrush (Artemisia tridentata).

  11. Effects of 24-Epibrassinolide on Antioxidant System in Cucumber Seedling Roots Under Hypoxia Stress

    Institute of Scientific and Technical Information of China (English)

    KANG Yun-yan; GUO Shi-rong; LI Juan; DUAN Jiu-ju

    2007-01-01

    This article aims to study the effects of exogenous 24-epibrassinolide (EBR) on the changes in ROS, activities of antioxidative enzymes and antioxidants in cucumber (Cucumis sativus L.) seedling roots under hypoxia stress. Seedlings of a hypoxianormoxic or hypoxic nutrient solutions that were added or not added with 10-3 mg L-1 EBR. Under hypoxia stress, the ROS levels and the lipid peroxidation were significantly increased in the roots upon exposure to hypoxia stress, which were inhibited by EBR application. The EBR treatment significantly increased the seedlings growth and SOD, APX, GR activities, and contents of AsA and GSH under hypoxia stress. From the results obtained in this study, it can be concluded that oxidative damage on seedling roots by hypoxia stress can be considerably alleviated and the tolerance of plants was elevated.

  12. The mycorrhizal fungus Tricholoma matsutake stimulates Pinus densiflora seedling growth in vitro.

    Science.gov (United States)

    Guerin-Laguette, Alexis; Shindo, Katsumi; Matsushita, Norihisa; Suzuki, Kazuo; Lapeyrie, Frédéric

    2004-12-01

    While it has been suggested that Matsutake mycorrhizae might not be functional and that Matsutake may behave as a saprobic fungus in soil or even have some pathogenic activity on seedlings, we investigated the consequences of Matsutake inoculation on Pinus densiflora growth. Seventy-five days after inoculation, hyphae were anchored on short roots and well-developed Hartig net palmettis were observed. Compared to both control treatments--seedlings treated with distilled water and seedlings treated with autoclaved mycelium--inoculation significantly stimulated seedling total dry weight by 70.9% and 98.0%, respectively. These findings attest that some type of symbiotic relationship must be functional and favour host growth, ruling out claims of pathogenicity under the sterile conditions used here.

  13. Interaction between a dark septate endophytic isolate from Dendrobium sp. and roots of D. nobile seedlings.

    Science.gov (United States)

    Hou, Xiao-Qiang; Guo, Shun-Xing

    2009-04-01

    Interactions between an isolate of dark septate endophytes (DSE) and roots of Dendrobium nobile Lindl. seedlings are reported in this paper. The isolate was obtained from orchid mycorrhizas on Dendrobium sp. in subtropical forest. The fungus formed typical orchid mycorrhiza in aseptic co-culture with D. nobile seedlings on modified Murashige-Skoog (MMS) medium. Anatomic observations of the infected roots showed that the DSE hyphae invaded the velamen layer, passed through passage cells in exodermis, entered the cortex cells, and then formed fungal pelotons of orchid mycorrhiza. D. nobile seedlings' plant height, stem diameter, new roots number and biomass were greatly enhanced by inoculating the fungus to seedlings. The fungus was identified as Leptodontidium by sequencing the polymerase chain reaction-amplified rDNA ITS1-5.8S-ITS2 (internal transcribed spacer (ITS)) regions and comparison with similar taxa.

  14. Association mapping of germinability and seedling vigor in sorghum under controlled low-temperature conditions

    National Research Council Canada - National Science Library

    Burrell, A. Millie; Upadhyaya, Hari D; Klein, Robert R; Wang, Yi-Hong; Prasad, P.V. Vara; Klein, Patricia E; Sastry, Dintyala V.S.S.R; Morris, Geoffrey P; Dwivedi, Sangam L

    2016-01-01

    ..., sorghum’s sensitivity to low soil temperatures adversely impacts seed germination. In this study, we evaluated the 242 accessions of the ICRISAT sorghum mini core collection for seed germination and seedling vigor at 12...

  15. Morphology and anatomy of the seedling and the tirodendro of Calophyllum brasiliense Cambess. (Clusiaceae

    Directory of Open Access Journals (Sweden)

    Valquíria Aparecida Mendes de Jesus

    2014-10-01

    Full Text Available Calophyllum brasiliense Cambess. is a tree species that is presented as an alternative to replace endangered species of hardwood. The morphology and anatomy of the seedling of this species is the object of the present study. Seedlings at different stages of development were obtained in greenhouse and analyzed fresh and fixed in FAA (Formalin-Acetic-Alcohol 50. The anatomical analysis was done by the freehand and microtome sections, according to standard techniques in plant anatomy. The seedling and/or tirodendro is cryptocotylar and hypogeal, has cataphylls, and presents eophylls and metaphylls simple with venation pinnate craspedodromous simple. The root is polyarch, the hypocotyl is very short, the cotyledons have an oily and starchy reserve, the epicotyl has stem structure, and eophylls and metaphylls are dorsiventral. The seedling may be classified in the Horsfieldia type/subtype.

  16. DRENCH OF SEEDLINGS AS ECOLOGICAL AND ECONOMIC FEASIBLE METHOD OF TOBACCO PROTECTION AGAINST WIREWORMS

    Directory of Open Access Journals (Sweden)

    Renata Bažok

    2012-06-01

    Full Text Available The cultivation of seedlings in hydroponics, the ban of methyl bromide and the discovery of highly systemic insecticides from the neonicotinoid group have opened up new possibilities in tobacco protection against pests. It was supposed that tobacco seedlings drenched in the solution of tiamethoxam would result in efficient protection of transplanted plants against wireworms. The efficacy of tiamethoxam applied as drench or irrigation of seedlings or transplanted plants was compared with the efficacy obtained by standard granular insecticide (tefluthrin in the two-year research in the condition of high infestation by Agriotes ustulatus Schall. larvae. The results show that drench of seedlings is easy and very practical method having satisfactory efficacy against wireworms. Even though statistical analysis doesn’t support this, it was obvious that a certain favorable impact of tiametoxam on the vigour of the plant (exuberant and faster growth and healthier appearance in general exists.

  17. Seedling stage strategies as a means of habitat specialization in herbaceous plants

    DEFF Research Database (Denmark)

    ten Brink, Dirk-Jan; Bruun, Hans Henrik

    2011-01-01

    The regeneration niche has been little investigated in studies of community assembly and plant distribution. We examined adaptive associations between seedling traits and habitat specialization. Two habitat contrasts were investigated across several evolutionary lineages of angiosperms: species...

  18. The role of vanillin and p-coumaric acid in the growth of Scotch pine seedlings

    Directory of Open Access Journals (Sweden)

    M. Michniewicz

    2015-01-01

    Full Text Available It was stated that vanillin and p-coumaric acid used at concentrations 10-8-10-5M stimulated the growth of pine seedlings. Most effective were these substances used at concentration 10-7M. Both phenolic compounds stimulated the elongation, fresh and dry weight in very young seedlings (up to 3-4 weeks and increased the fresh and dry weight only in older ones (7 weeks. The stimulation of growth processes in pine seedlings treated with vanillin and p-coumaric acid coincided with the increase of auxins in roots and with the decrease of free gibberellins in these plant organs. Neither vanillin nor p-coumaric acid influenced the level of ABA-like inhibitor both in the shoots and roots of pine seedlings.

  19. BIO-ACCUMULATION AND RELEASE OF MERCURY IN VIGNA MUNGO (L. HEPPER SEEDLINGS

    Directory of Open Access Journals (Sweden)

    Hussain. K

    2010-09-01

    Full Text Available Effect of mercury on the seedling of Vigna mungo seedlings was studied by culturing the seedlings in Hoagland medium artificially contaminated with 5 and 10mM Mercuric Chloride. Histochemical localization of the mercury in shoot and root tissues was done by staining with dithizone and quantitative analyses of mercury content accumulated in root, stem and leaf tissues were done using mercury analyser. Localization of mercury was observed as coloured masses in the cells of root and stem. Stem tissues of seedlings showed anatomical modification in the epidermal cells as trichomes. Patterns of bioaccumulation of mercury was root> stem> leaves revealing feeble translocation to the shoot system. A comparison of residual mercury content retained in the growth medium after sample harvesting and quantity accumulated in the plant body reveals that some quantity of mercury is lost presumably through the trichomes developed on the stem and/ or through stomata of the leaves.

  20. Community-wide spatial and temporal discordances of seed-seedling shadows in a tropical rainforest

    National Research Council Canada - National Science Library

    Rother, Débora Cristina; Pizo, Marco Aurélio; Siqueira, Tadeu; Rodrigues, Ricardo Ribeiro; Jordano, Pedro

    2015-01-01

    ... (bamboo and non-bamboo stands) from the Brazilian Atlantic Forest. Spatial distribution patterns, spatial concordance between seed rain and seedling recruitment between subsequent years in two fruiting seasons...

  1. Effects of soilless and soil-based nursery media on seedling ...

    African Journals Online (AJOL)

    Effects of soilless and soil-based nursery media on seedling emergence, growth and response to water stress of African breadfruit (Treculia africana Decne) ... African Journal of Biotechnology. Journal Home · ABOUT · Advanced Search ...

  2. Agroforestry wastes used for germination and development of sweet angelim seedlings

    Directory of Open Access Journals (Sweden)

    João Ricardo Avelino Leão

    2013-03-01

    Full Text Available This paper aimed to define the ideal type of agroforestry substrate and the adequate depth of sweet angelim sowing, providing information on the development of seedlings, as well as on low-cost substrates which are easy to be obtained. An experiment in a greenhouse was carried out, in a completely randomized design with treatments distributed in a factorial scheme (5x3, with the factors agroforestry substrates and depths being replicated seven times with a seed in each container. The following parameters were analyzed: germination percentage, germination speed index, total dry weight, number of leaves, seedlings height and coll diameter, and Dickson’s seedling quality index. The results showed that the most suitable substrate for germination and development of this native species was that containing Brazil nut shell, peanut hull, or açai seed, and the ideal depth for sowing and managing seedlings was on the surface.

  3. Produce of seedlings of cedar in function of types of container and fertilization sources

    Directory of Open Access Journals (Sweden)

    Osmar Henrique de Castro Pias

    2015-06-01

    Full Text Available The aim of this study was to evaluate the production of cedar seedlings according to the size of containers and nutrient sources. It was tested three types of containers (Root trainers, plastic bag and plastic vase, three sources of fertilization (Conventional, Kimcoat® and Osmocote® in seven evaluations. The cedar seedlings in root trainers, fertilized with source Osmocote® presented the greatest increments in height and stem diameter when compared to another sources of fertilization. The plastic bag and plastic vase containers promoted similar seedlings height growth. However the seedlings grown in plastic vase presented greatest growth in stem diameter when compared with the ones in plastic bag.

  4. Novel plant communities limit the effects of a managed flood to restore riparian forests along a large regulated river

    Science.gov (United States)

    Cooper, D.J.; Andersen, D.C.

    2012-01-01

    Dam releases used to create downstream flows that mimic historic floods in timing, peak magnitude and recession rate are touted as key tools for restoring riparian vegetation on large regulated rivers. We analysed a flood on the 5th-order Green River below Flaming Gorge Dam, Colorado, in a broad alluvial valley where Fremont cottonwood riparian forests have senesced and little recruitment has occurred since dam completion in 1962. The stable post dam flow regime triggered the development of novel riparian communities with dense herbaceous plant cover. We monitored cottonwood recruitment on landforms inundated by a managed flood equal in magnitude and timing to the average pre-dam flood. To understand the potential for using managed floods as a riparian restoration tool, we implemented a controlled and replicated experiment to test the effects of artificially modified ground layer vegetation on cottonwood seedling establishment. Treatments to remove herbaceous vegetation and create bare ground included herbicide application (H), ploughing (P), and herbicide plus ploughing (H+P). Treatment improved seedling establishment. Initial seedling densities on treated areas were as much as 1200% higher than on neighbouring control (C) areas, but varied over three orders of magnitude among the five locations where manipulations were replicated. Only two replicates showed the expected seedling density rank of (H+P)>P>H>C. Few seedlings established in control plots and none survived 1 year. Seedling density was strongly affected by seed rain density. Herbivory affected growth and survivorship of recruits, and few survived nine growing seasons. Our results suggest that the novel plant communities are ecologically and geomorphically resistant to change. Managed flooding alone, using flows equal to the pre-dam mean annual peak flood, is an ineffective riparian restoration tool where such ecosystem states are present and floods cannot create new habitat for seedling establishment

  5. Grafting Seedling Techniques of Chestnut%板栗嫁接育苗技术

    Institute of Scientific and Technical Information of China (English)

    李国举

    2014-01-01

    Grafting seedling techniques of chestnut were summarized from rootstock breeding,scion collecting and processing,grafting etc.,so as to provide reference for seedling of chestnut growers.%从砧木培育、接穗采集及处理、嫁接等方面总结了板栗嫁接育苗技术,以期为板栗种植者育苗提供参考。

  6. Root system architecture: The invisible trait in container longleaf pine seedlings

    Science.gov (United States)

    Shi-Jean Susana Sung; R. Kasten Dumroese

    2013-01-01

    Longleaf pine (Pinus palustris Mill.) seedlings cultured in four cavity volumes (60 to 336 ml [3.7 to 20.5 cubic inches]), two root pruning treatments (with or without copper coating), and 3 nitrogen levels (low to high) were grown for 29 weeks before they were outplanted into an open area in central Louisiana. Twenty-two months after outplanting, 3 seedlings were...

  7. Addressing post-transplant summer water stress in Pinus pinea and Quercus ilex seedlings

    Directory of Open Access Journals (Sweden)

    Pardos M

    2015-06-01

    Full Text Available In central Spain, post-transplant water stress produces high seedling mortality after the first summer following outplanting. Our study was designed to determine whether survival and performance of outplanted stone pine (Pinus pinea and holm oak (Quercus ilex seedlings in a burned area could be improved by summer irrigation and mulching and to identify whether there is a species-specific adaptive capacity to respond to treatment and environment. Seedlings were outplanted in March 2011 in 200 planting holes in an area of 1.1 ha. Mulch was added in June; irrigation started in July and was repeated every week until mid-September. The severity of the 2011 summer drought constrained growth rates and photosynthetic characteristics, mainly in the non-irrigated seedlings, whose survival at the end of the year after planting was approximately 2.5%. Stone pine and holm oak seedlings responded more to irrigation than to mulching in terms of shoot growth, biomass and survival. Furthermore, stone pine seedlings were found to be more responsive to the partial alleviation of summer drought than holm oak seedlings. Irrigation alone produced similar results to those obtained when both irrigation and mulching were employed. In conclusion, first year summer irrigation should be considered as a planned adaptation measure in the management of outplanted Mediterranean ecosystems, because once a gravimetrically measured soil moisture level as low as 2% is achieved seedling survival and physiological performance can be guaranteed. However, the repercussions for the potential persistence of both species in the area will not only be related to the recurrence and intensity of summer droughts but also to drought duration.

  8. Short-term toxic effects of chlorobenzenes on broadbean (Vicia faba) seedlings.

    Science.gov (United States)

    Liu, Wan; Li, Peijun; Zhou, Qixing; Sun, Tieheng; Tai, Peidong; Xu, Huaxia

    2005-05-01

    The root growth, changes in superoxide dismutase (SOD, EC 1.15.1.1) activity, malonyldialdehyde (MDA) and total soluble protein level of broadbean (Vicia faba) seedlings were researched at different soil concentrations of chlorobenzene (CB), 1,2,4-trichlorobenzene (TCB) and hexachlorobenzene (HCB). The results showed that root growth of seedlings was interrupted after 5 d of 50-200 microg x g(-1) TCB treatment. During a 3 d recovery period, root growth was, however, restored to some extent although there was a delay in returning to the control level. The total soluble protein content in seedlings increased with TCB concentration and duration of exposure. Effect of TCB stress on SOD activity in seedlings displayed a significant dose-effect relationship for 1-5 d of 50-200 microg x g(-1) treatment. When broadbean seedlings were placed in clean tap water for 3 d following exposure to 5 d of TCB stress to clear tap water for 3 d, SOD activity at 50 microg x g(-1) TCB recovered towards control level (P>0.05) while a significant increase in SOD activity was observed at 100 and 200 microg x g(-1) TCB compared to control (P<0.05). The experiments also revealed that a significant increase of MDA level in seedlings occurred after 3 and 5 d of 100 and 200 microg x g(-1) TCB treatment (P<0.05 and P<0.01), and there was a positive correlation between TCB concentration and MDA level. All the above results showed that SOD activity and MDA level of broadbean seedlings might be proposed as the biomarkers for short-term TCB contamination in soil. Compared to TCB, the toxicity of 50-1000 microg x g(-1) CB or HCB in soil to broadbean seedlings was not observed after a 3 d exposure.

  9. Physiological responses of seedlings of two oak species to flooding stress

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The physiological responses of 2-year-old seedlings of Nuttall's oak (Quercus nuttalli) and Southern red oak (Q. falcata) with two treatments i.e., deep-drowning and shallow-drowning, were studied. Taxodium distichum was selected as a control. The survival rates of seedlings were calculated, the photosynthetic indices were detected by Licor-6400 photosynthetic system instrument,and the root activities of seedlings were tested by the method of triphenyltetrazolium chloride (TTC). Results showed that: 1) By experiencing flooding for 76 d and recovering for 60 d after water was drained off, all seedlings survived under the shallow-drowning treatment. None of Q. falcata seedlings died in the deep-drowning treatment until the 49th day. The survival rate of Q. falcata in the deep-drowning treatment was 30%. 2) Within 61 d of waterlogging treatments, the net photosynthetic rate (Pn), stomatal conductance (gs) and transpiration rate (Tr) showed a tendency of declining, but intercellular concentration of CO2 (Ci) increased. With the pro-longation of flooding stress, the extents of variation for all indices under deep-drowning treatment were larger than those under the shallow-drowning treatment. The variation of Q. falcata in flooding stress was larger than that of Q. nuttallii. 3) The root vigor and alcohol dehydrogenase (ADH) activities were detected at the 61st day in flooding stress. Waterlogging obviously inhibited root ac-tivities. Shallow-drowning made root vigor of Q. nuttallii decreased by 11.7%, and for Q. falcata, by 51.88%. Shallow-drowning treatment had no remarkable effects on ADH activities of seedlings, but deep-&owning increased those of Q. nuttallii seedlings by 227.24%, and decreased those of Q. falcata seedlings by 59.22% in the meantime. We conclude that Q. nuttallii had a stronger wa-terlogging resistance than Q. falcata, but weaker than T. distichum.

  10. Araucaria cunninghamii Seedling Response to Different Forms and Rates of 15N-Labelled Fertiliser

    Institute of Scientific and Technical Information of China (English)

    T.J.BLUMFIELD; XU Zhi-Hong

    2006-01-01

    Nitrogenous fertilisers are under consideration for promoting the growth of nursery-reared hoop pine (Araucaria cunninghamii Aiton ex A. Cunn) seedlings in the establishment phase of second rotation (2R) plantations. Using 15Nlabelled fertilisers, we investigated the effect of different forms (ammonium sulphate, ammonium nitrate, potassium nitrate and urea) and rates of application (0, 150 and 300 mg N kg-1 dried soil) of fertilisers on the growth, 15N recovery and carbon isotope composition (δ13C) of hoop pine seedlings in a 12-month glasshouse trial in southeast Queensland,Australia. The 15N-labelled fertilisers were applied to nursery-reared hoop pine seedlings, which were then grown in pots,containing ca. 1.2 kg dried soil, under well watered conditions for 12 months. Four seedlings from each treatment were harvested at 4-month intervals, divided into roots, stem and foliage, with a further subdivision for new and old foliage,and then analysed for 15N, total N, δ13C and total C. There was no significant response in the seedling growth to the form or rate of application of nitrogen (N) fertiliser within the 12-month period, indicating that the seedlings did not experience N deficiency when grown on second rotation hoop pine soils. While the combined 15N recovery from soil and plant remained at around 70% throughout the experiment, the proportion of 15N recovered from the plants increasing steadily over time. Nitrate containing fertilisers at 150 mg N kg-1 soil gradually increased seedling foliage δ13C over the 12-month period, indicating an increase in seedling water use efficiency.

  11. Magnetic field can alleviate toxicological effect induced by cadmium in mungbean seedlings.

    Science.gov (United States)

    Chen, Yi-ping; Li, Ran; He, Jun-Min

    2011-06-01

    To alleviate toxicological effect induced by cadmium in mungbean seedlings, seeds were divided into four groups: The controls groups (CK, without treatment), magnetic field treated groups (MF), cadmium treated groups (CS), and magnetic field treated followed by cadmium treated groups (MF + CS).The results showed: (i) Compared with the controls, cadmium stress resulted in enhancing in the concentration of malondialdehyde, H(2)O(2) and O(2-), and the conductivity of electrolyte leakage while decreasing in the nitrice oxide synthase (NOS) activity, the concentration of nitrice oxide (NO), chlorophyll and total carbon and nitrogen, the net photosynthetic rate, the stomatal conductance, the transpiration rate, the water use efficiency, the lateral number and seedlings growth except for intercellular CO(2) concentration increase. However, the seedlings treated with 600 mT magnetic field followed by cadmium stress the concentration of malondialdehyde, H(2)O(2) and O(2-), and the conductivity of electrolyte leakage decreased, while the above mentioned NO concentration, NOS activity, photosynthesis and growth parameters increased compared to cadmium stress alone. (ii) Compared with the cadmium stress (CS), the seedling growth were inhibited when the seeds were treated with NO scavenger (hemoglobin, HB) and inhibition of NO generating enzyme (sodium tungstate, ST), conversely, the seedling growth were improved by the NO donor sodium nitroprusside (SNP) and CaCl(2). In the case of the HB and ST treatment followed by magnetic field and then the seedling subjected to CS, the seedlings growth was better than that of hemoglobin (HB) followed by CS and ST followed by CS. The seeds were treated with SNP and CaCl(2) followed by MF, and then subjected to CS, the seedlings growth were better than that of SNP followed by CS, and CaCl(2) followed by CS. These results suggested that magnetic field compensates for the toxicological effects of cadmium exposure are related to NO signal.

  12. Performance of northern red oak seedlings across a pH gradient

    Science.gov (United States)

    Anthony S. Davis; Douglass F. Jacobs

    2005-01-01

    Northern red oak (Quercus rubra L.) seedlings were grown from acorns in 4-gallon containers in a greenhouse. Growing medium was amended to a pH of 3.50, 4.25, 5.00, and 5.75 using tri-weekly applications of aluminum sulfate. In addition, seedlings were subjected to either: (1) addition of a 16- to 18-month controlled release fertilizer (CRF), (2)...

  13. Production of gherkin seedlings in coconut fiber fertirrigated with different nutrient solutions

    OpenAIRE

    Francisco de Assis Oliveira; Maria da Saúde de Souza Ribeiro; Mychelle Karla Teixeira de Oliveira; Daniele Campos Martins; Maria Lilia de Souza Neta; José Francismar de Medeiros

    2016-01-01

    ABSTRACT Seedling quality is a key factor to achieve success in vegetable production. The present work aimed to evaluate the production of gherkin seedlings in substrate of coconut fiber fertirrigated with different concentrations of nutrients. The experimental design was completely randomized in a 3 × 5 factorial with four replications. The treatments consisted of combinations of three cultivars of gherkin (Do Norte, Liso de Calcutá, e Liso Gibão) with five concentrations of nutrients in th...

  14. Seedling-nursing technique for olive%橄榄树育苗技术

    Institute of Scientific and Technical Information of China (English)

    叶倩倩

    2015-01-01

    总结橄榄树育苗技术,主要包括品种选择、育苗方法、幼苗培育和管理、嫁接方法等方面内容。%Seedling-nursing technique for olive were summarized in this paper,including variety selection,breeding way, seedling cultivation and management,grafting method,etc.

  15. Effect of mycorrhizae o f pine seedlings on the utilization of different mineral phosphorus sources

    Directory of Open Access Journals (Sweden)

    Roman Pachlewski

    2014-08-01

    Full Text Available Pine seedlings (P. sylvestris L. growing on the unsterilized sand, with addition of different phosphorus sources, were inoculated with ectomycorrhizal fungi. Lack of P in the substrate restricted mycorrhizal infection of roots. In the presence of AIPO4 and FePO4 inoculation with A. verna and H. mesophaeum have positive effect on the seedlings growth and survival. Strain of H. mesophaeum intensified the phosphorus uptakc, particulary when FePO4 was applied.

  16. Growth and heavy metal accumulation of Koelreuteria paniculata seedlings and their potential for restoring manganese mine wastelands in Hunan, China.

    Science.gov (United States)

    Huang, Zhihong; Xiang, Wenhua; Ma, Yu'e; Lei, Pifeng; Tian, Dalun; Deng, Xiangwen; Yan, Wende; Fang, Xi

    2015-02-03

    The planting of trees on mine wastelands is an effective, long-term technique for phytoremediation of heavy metal-contaminated wastes. In this study, a pot experiment with seedlings of Koelreuteria paniculata under six treatments of local mine wastes was designed to determine the major constraints on tree establishment and to evaluate the feasibility of planting K. paniculata on manganese mine wastelands. Results showed that K. paniculata grew well in mine tailings, and also under a regime of equal amounts of mine tailings and soil provided in adjacent halves of pots. In contrast, mine sludge did not favor survival and growth because its clay texture limited fine root development. The bio-concentration factor and the translocation factor were mostly less than 1, indicating a low phytoextraction potential for K. paniculata. K. paniculata is suited to restore manganese mine sludge by mixing the mine sludge with local mine tailings or soil.

  17. Growth and Heavy Metal Accumulation of Koelreuteria Paniculata Seedlings and Their Potential for Restoring Manganese Mine Wastelands in Hunan, China

    Directory of Open Access Journals (Sweden)

    Zhihong Huang

    2015-02-01

    Full Text Available The planting of trees on mine wastelands is an effective, long-term technique for phytoremediation of heavy metal-contaminated wastes. In this study, a pot experiment with seedlings of Koelreuteria paniculata under six treatments of local mine wastes was designed to determine the major constraints on tree establishment and to evaluate the feasibility of planting K. paniculata on manganese mine wastelands. Results showed that K. paniculata grew well in mine tailings, and also under a regime of equal amounts of mine tailings and soil provided in adjacent halves of pots. In contrast, mine sludge did not favor survival and growth because its clay texture limited fine root development. The bio-concentration factor and the translocation factor were mostly less than 1, indicating a low phytoextraction potential for K. paniculata. K. paniculata is suited to restore manganese mine sludge by mixing the mine sludge with local mine tailings or soil.

  18. Systemic Infection of Maize, Sorghum, Rice, and Beet Seedlings with Fumonisin-Producing and Nonproducing Fusarium verticillioides Strains

    Directory of Open Access Journals (Sweden)

    Raana Dastjerdi

    2015-12-01

    Full Text Available Two fumonisin-nonproducing strains of Fusarium verticillioides and their fumonisin producing progenitors were tested for aggressiveness toward maize, sorghum, rice, and beetroot seedlings grown under greenhouse conditions. None of the plants showed obvious disease symptoms after root dip inoculation. Fungal biomass was determined by species-specific real-time PCR. No significant (P = 0.05 differences in systemic colonization were detected between the wild type strains and mutants not producing fumonisins. F. verticillioides was not detected in any of the non-inoculated control plants. The fungus grew from roots to the first two internodes/leaves of maize, rice and beet regardless of fumonisin production. The systemic growth of F. verticillioides in sorghum was limited. The results showed that fumonisin production was not required for the infection of roots of maize, rice and beet by F. verticillioides.

  19. Growth and nutrient balance of Enterolobium contortsiliquum seedlings with addition of organic substrates and wastewater

    Directory of Open Access Journals (Sweden)

    Emanuel França Araújo

    2016-06-01

    Full Text Available Given the strong generation of solid organic waste and wastewater, the use of these materials as a primary source of nutrients is an important practice in environmental management, especially in the production of seedlings with emphasis on degraded areas. The objective of this study was to evaluate growth and nutrient balance of “tamboril” (Enterolobium contortsiliquum (Vell. Morong seedlings grown on substrates with different formulations proportions of organic matter irrigated with wastewater. It was tested five ratios of organic composts and soil: 0:100; 20:80; 40:60; 60:40 and 80:20 v/v. Two procedences of irrigation water was tested: water supply and wastewater from swine farming, arranged in a completely randomized design in a factorial scheme 5 x 2, with four replications. At 90 days, we evaluate seedlings morphological variables, the integrate diagnosis recommendation index and the nutrient balance index. The organic residue contributes to seedlings growth and nutritional balance. The proportion 80:20 proved to be the most suitable for “tamboril” seedlings production. Seedlings presented lower growth and nutritional balance when irrigate with swine farm wastewater.

  20. Effects of aluminum on growth, development, and nutrient composition of honeylocust (Gleditsia triacanthos L.) seedlings.

    Science.gov (United States)

    Thornton, F. C.; Schaedle, M.; Raynal, D. J.

    1986-12-01

    Hydroponic experiments were conducted to determine the effects of aluminum (Al) on root development, shoot morphology and the nutrient composition of honeylocust seedlings (Gleditsia triacanthos L.). Seedlings were grown at pH 4 in a nutrient solution containing 0, 50, 150, 600 or 1500 microM Al. Within seven days, there were significant differences in root growth and root nutrient composition between control seedlings and seedlings grown in the presence of 150 or 600 microM Al. By day 14, significant reductions in leaf production and plant height were observed in seedlings treated with 1500 microM Al. At the lowest Al concentration, 50 microM, leaf size and expansion rates were significantly lower than in the controls. By the third week of the experiment, Ca and Mg concentrations in young leaves of the Al-treated seedlings were significantly lower than in leaves of control plants. Analysis of old leaf tissue, however, revealed no consistent pattern of nutrient concentration with Al treatment.