Minimizing Risks of Invasive Alien Plant Species in Tropical Production Forest Management

Directory of Open Access Journals (Sweden)

Michael Padmanaba

2014-08-01

Full Text Available Timber production is the most pervasive human impact on tropical forests, but studies of logging impacts have largely focused on timber species and vertebrates. This review focuses on the risk from invasive alien plant species, which has been frequently neglected in production forest management in the tropics. Our literature search resulted in 114 publications with relevant information, including books, book chapters, reports and papers. Examples of both invasions by aliens into tropical production forests and plantation forests as sources of invasions are presented. We discuss species traits and processes affecting spread and invasion, and silvicultural practices that favor invasions. We also highlight potential impacts of invasive plant species and discuss options for managing them in production forests. We suggest that future forestry practices need to reduce the risks of plant invasions by conducting surveillance for invasive species; minimizing canopy opening during harvesting; encouraging rapid canopy closure in plantations; minimizing the width of access roads; and ensuring that vehicles and other equipment are not transporting seeds of invasive species. Potential invasive species should not be planted within dispersal range of production forests. In invasive species management, forewarned is forearmed.

Accumulation and long-term behavior of radiocaesium in tropical plants

International Nuclear Information System (INIS)

Carvalho, C.; Mosquera, B.; Anjos, R.M.; Sanches, N.; Bastos, J.; Macario, K.; Veiga, R.

2006-01-01

The accumulation and distribution of 40 K and 137 Cs in tropical plant species were studied through measurements of gamma-ray spectra from mango, avocado, guava, pomegranate, chili pepper, papaya and manioc trees. Our goal was to infer their differences in the uptake and translocation of ions to the aboveground plant parts and to establish the suitability of using radiocaesium as a tracer for the plant uptake of nutrients such as K + . (author)

STUDIES ON FUNCTIONAL BACTERIA OF INDONESIAN TROPICAL FOREST PLANTS FOR BIOREHABILITATION OF DEGRADED LANDS

Directory of Open Access Journals (Sweden)

Irnayuli R. Sitepu

2008-06-01

Full Text Available Forest  degradations  have left vast amount  of damaged  and abandoned  lands in Indonesia.   In this paper, we present our approaches  in rehabilitation of adverse soils using functional  bacteria isolated from plant species of Indonesian tropical  rain forests. For these purposes,  we collected  bacteria  from various  bio-geo-climatically different forests and conducted bioassays to test these bacterial abilities in improving plant growth. Repeated seedling-based studies on Shorea spp., Alstonia scholaris, Acacia crassicarpa, and Agathis lorantifolia have revealed that many bacteria were able to promote plant growth at early stage in the nursery.  Various  plant responses towards  inoculations suggested that although  forest soils maintain  highly diverse and potent  bacteria,  it is necessary to select appropriate approaches to obtain optimum  benefits from these plant-bacteria interactions.  Our  ideas and futures  studies  for further  management  of these plant- bacteria interactions for biorehabilitation are also discussed.

Accumulation and long-term behavior of radiocaesium in tropical plants

Energy Technology Data Exchange (ETDEWEB)

Carvalho, C.; Mosquera, B.; Anjos, R.M.; Sanches, N.; Bastos, J.; Macario, K.; Veiga, R. [Universidade Federal Fluminense, Niteroi, RJ (Brazil). Inst. de Fisica

2006-12-15

The accumulation and distribution of {sup 40}K and {sup 137}Cs in tropical plant species were studied through measurements of gamma-ray spectra from mango, avocado, guava, pomegranate, chili pepper, papaya and manioc trees. Our goal was to infer their differences in the uptake and translocation of ions to the aboveground plant parts and to establish the suitability of using radiocaesium as a tracer for the plant uptake of nutrients such as K{sup +}. (author)

Biological effects of plant residues with constrasting chemical compositions on plant and soil under humid tropical conditions

NARCIS (Netherlands)

Tian, G.

1992-01-01

A study on plant residues with contrasting chemical compositions was conducted under laboratory, growth chamber and humid tropical field conditions to understand the function of the soil fauna in the breakdown of plant residues, the cycling of nutrients, in particular nitrogen, and the

Plant litter dynamics in the forest-stream interface: precipitation is a major control across tropical biomes

OpenAIRE

Tonin, Alan M.; Gon?alves, Jos? F.; Bambi, Paulino; Couceiro, Sheyla R. M.; Feitoza, Lorrane A. M.; Fontana, Lucas E.; Hamada, Neusa; Hepp, Luiz U.; Lezan-Kowalczuk, V?nia G.; Leite, Gustavo F. M.; Lemes-Silva, Aurea L.; Lisboa, Leonardo K.; Loureiro, Rafael C.; Martins, Renato T.; Medeiros, Adriana O.

2017-01-01

Riparian plant litter is a major energy source for forested streams across the world and its decomposition has repercussions on nutrient cycling, food webs and ecosystem functioning. However, we know little about plant litter dynamics in tropical streams, even?though the tropics occupy 40% of the Earth?s land surface. Here we investigated spatial and temporal (along a year cycle) patterns of litter inputs and storage in multiple streams of three tropical biomes in Brazil (Atlantic forest, Ama...

Isolation, diversity, and antimicrobial activity of rare actinobacteria from medicinal plants of tropical rain forests in Xishuangbanna, China.

Science.gov (United States)

Qin, Sheng; Li, Jie; Chen, Hua-Hong; Zhao, Guo-Zhen; Zhu, Wen-Yong; Jiang, Cheng-Lin; Xu, Li-Hua; Li, Wen-Jun

2009-10-01

Endophytic actinobacteria are relatively unexplored as potential sources of novel species and novel natural products for medical and commercial exploitation. Xishuangbanna is recognized throughout the world for its diverse flora, especially the rain forest plants, many of which have indigenous pharmaceutical histories. However, little is known about the endophytic actinobacteria of this tropical area. In this work, we studied the diversity of actinobacteria isolated from medicinal plants collected from tropical rain forests in Xishuangbanna. By the use of different selective isolation media and methods, a total of 2,174 actinobacteria were isolated. Forty-six isolates were selected on the basis of their morphologies on different media and were further characterized by 16S rRNA gene sequencing. The results showed an unexpected level of diversity, with 32 different genera. To our knowledge, this is the first report describing the isolation of Saccharopolyspora, Dietzia, Blastococcus, Dactylosporangium, Promicromonospora, Oerskovia, Actinocorallia, and Jiangella species from endophytic environments. At least 19 isolates are considered novel taxa by our current research. In addition, all 46 isolates were tested for antimicrobial activity and were screened for the presence of genes encoding polyketide synthetases and nonribosomal peptide synthetases. The results confirm that the medicinal plants of Xishuangbanna represent an extremely rich reservoir for the isolation of a significant diversity of actinobacteria, including novel species, that are potential sources for the discovery of biologically active compounds.

Application of digital field photographs as documents for tropical plant inventory1

Science.gov (United States)

LaFrankie, James V.; Chua, Anna I.

2015-01-01

Premise of the study: We tested the credibility and significance of digital field photographs as supplements or substitutes for conventional herbarium specimens with particular relevance to exploration of the tropics. Methods: We made 113 collections in triplicate at a species-rich mountain in the Philippines while we took 1238 digital photographs of the same plants. We then identified the plants from the photographs alone, categorized the confidence of the identification and the reason for failure to identify, and compared the results to identifications based on the dried specimens. Results: We identified 72.6% of the photographic sets with high confidence and 27.4% with low confidence or only to genus. In no case was a confident identification altered by subsequent examination of the dried specimen. The failure to identify photographic sets to species was due to the lack of a key feature in 67.8% of the cases and due to a poorly understood taxonomy in 32.2%. Discussion: We conclude that digital photographs cannot replace traditional herbarium specimens as the primary elements that document tropical plant diversity. However, photographs represent a new and important artifact that aids an expedient survey of tropical plant diversity while encouraging broad public participation. PMID:25995976

Underexploited tropical plants with promising economic value

Energy Technology Data Exchange (ETDEWEB)

1975-01-01

The apparent advantages of staple plants over the minor tropical plants often result only from the disproportionate research attention they have been given. A world-wide inquiry resulted in a list of 400 promising but neglected species. The 36 most important species are described in compact monographs and concern cereals (Echinochloa turnerana, grain amaranths, quinua and Zosterea mazina), roots and tubers (Arrachacha, cocoyams and taro), vegetables (chaya, hearts of palms, wax gourd, winged bean), fruits (durian, mangosteen, naranjilla, pejibaye, pummelo, soursop, uvilla), oilseeds (babassu palm, buffalo gourd, Caryocar species, Hessenia polycarpa and jojoba), forage (Acacia albida, Brosimum alicastrum Cassia sturtii, saltbushes and tamarugo) and other crops (buriti palm, Calathea lutea, candelilla, guar, guayule, Paspalum vaginatum, ramie and Spirulina).

Mutualism, hybrid inviability and speciation in a tropical ant-plant.

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Léotard, G; Saltmarsh, A; Kjellberg, F; McKey, D

2008-07-01

Although biotic interactions are particularly intricate in the tropics, few studies have examined whether divergent adaptations to biotic interactions lead to speciation in tropical organisms. Ant-plant mutualisms are widespread in the tropics. Within Leonardoxa africana, two subspecies present contrasting defences against herbivores. Young leaves of subsp. africana are defended by mutualistic ants, whereas subsp. gracilicaulis satiates herbivores by synchronized leaf production. Subsp. africana possesses hollow internodes and many large foliar nectaries, housing and feeding ants. We detected no genetic introgression between the two subspecies in the contact zone between them. F1 hybrids were present. They were intermediate in phenotype, expressing reduced, nonfunctional but costly myrmecophilic traits. However, they suffered more herbivory than their parents. Hybrids remained small, failing to reach reproductive size, probably due to their maladapted defence phenotype. Hence, there could be a direct link between adaptation to mutualism and reproductive isolation: biotic interactions could be a driver of tropical diversity.

Gastrointestinal nematode infection does not affect selection of tropical foliage by goats in a cafeteria trial.

Science.gov (United States)

Ventura-Cordero, J; González-Pech, P G; Jaimez-Rodriguez, P R; Ortíz-Ocampo, G I; Sandoval-Castro, C A; Torres-Acosta, J F J

2017-01-01

It is important to determine whether gastrointestinal nematodes (GINs) affect foliage choice of goats leading to confirm the expression of a self-medication behavior. This study investigated the effect of GIN infection on tropical foliage selection by goats. During experimental stage 1 (10 days), goats had a natural mixed GIN infection, and at stage 2 (10 days), goats were treated with effective anthelmintics to maintain them free of GIN infection. During stage 1 the twelve adult goats (32 ± 2.3 kg live weight [LW]) were assigned to three groups (n = 4) according to their initial GIN infection status: HI group, with fecal egg count (FEC) between 1450 and 2150 eggs per g/feces (EPG); MI group, medium FEC (592-1167 EPG); and the NI group, free from GIN infection. Fresh foliage of four tropical plants were offered to goats ad libitum for 1 h daily: Gymnopodium floribundum (high condensed tannin [CT] content, 37-40 %), Mimosa bahamensis (medium CT content, 16-17 %), Leucaena leucocephala (low CT content, 3-5 %), and Viguiera dentata (negligible CT content, 0.6-0.9 %). Jacobs' selection indexes (JSIs) were estimated for the experimental foliage based on dry matter (DM), CT, or crude protein (CP) intake. During both study stages, individual fecal egg counts were estimated. The JSI patterns of different plant species, based on DM, CT, or CP, were similar irrespective of infection level during stage 1 (HI, MI, and NI) or no GIN infection (stage 2). Thus, irrespective of GIN infection, goats actively selected M. bahamensis (high CT, low CP content) and V. dentata (negligible CT, high CP content) but avoided G. floribundum (high CT, low CP content) and L. leucocephala (medium CT and high CP content). Thus, natural GIN infection did not influence goats' foliage selection.

Stable isotopic variation in tropical forest plants for applications in primatology.

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Blumenthal, Scott A; Rothman, Jessica M; Chritz, Kendra L; Cerling, Thure E

2016-10-01

Stable isotope analysis is a promising tool for investigating primate ecology although nuanced ecological applications remain challenging, in part due to the complex nature of isotopic variability in plant-animal systems. The aim of this study is to investigate sources of carbon and nitrogen isotopic variation at the base of primate food webs that reflect aspects of primate ecology. The majority of primates inhabit tropical forest ecosystems, which are dominated by C3 vegetation. We used stable isotope ratios in plants from Kibale National Park, Uganda, a well-studied closed-canopy tropical forest, to investigate sources of isotopic variation among C3 plants related to canopy stratification, leaf age, and plant part. Unpredictably, our results demonstrate that vertical stratification within the canopy does not explain carbon or nitrogen isotopic variation in leaves. Leaf age can be a significant source of isotopic variation, although the direction and magnitude of this difference is not consistent across tree species. Some plant parts are clearly differentiated in carbon and nitrogen isotopic composition, particularly leaves compared to non-photosynthetic parts such as reproductive parts and woody stem parts. Overall, variation in the isotopic composition of floral communities, plant species, and plant parts demonstrates that stable isotope studies must include analysis of local plant species and parts consumed by the primates under study from within the study area. Am. J. Primatol. 78:1041-1054, 2016. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

Plant biodiversity changes in Carboniferous tropical wetlands

DEFF Research Database (Denmark)

Cleal, C. J.; Uhl, D.; Cascales-Miñana, B.

2012-01-01

and Sydney coal basins. In all cases, species richness expansion followed an essentially logistic curve typical of that associated with ecologically closed habitats, with niche saturation being achieved in about three million years. The resulting steady-state (“climax”) coal swamp vegetation had a local......Using a combination of species richness, polycohort and constrained cluster analyses, the plant biodiversity of Pennsylvanian (late Carboniferous) tropical wetlands (“coal swamps”) has been investigated in five areas in Western Europe and eastern North America: South Wales, Pennines, Ruhr, Saarland...

Layout Guide for Burnt and Un-burnt Tropical Forest: The Diversity of Forest Plants and Insetcs for Sustainable Environmental

Science.gov (United States)

Watiniasih, N. L.; Tambunan, J.; Merdana, I. M.; Antara, I. N. G.

2018-04-01

Forest fire is a common phenomenon in tropical forest likes in Indonesia. Beside the effect of soaring heat and lack of rain during dry season due to the tropical climate, farming system is also reported as one reason of forest fire in Indonesia. People of surrounding areas and neighbouring countries are suffering from the effect of forest fire. Plants and animals are the most suffer from this occurrence that they cannot escape. This study aimed to investigate the effect of previously burnt and un-burnt tropical forest in Borneo Island on the plant and insect diversity of the tropical forest. The result of the study found that the plants in previously burnt forest area was dominated by one species, while higher and more stable plant diversity was found in un-burnt forest. Although the number of individual insects was higher in previously burnt tropical forest, but the insects was more diverse in un-burnt tropical forest. The alteration of environmental conditions in previously burnt and un-burnt forest indicate that the energy held in natural forest support higher number and more stable insects than previously burnt forest.

Comparisons of invasive plants in southern Africa originating from southern temperate, northern temperate and tropical regions

Directory of Open Access Journals (Sweden)

L. Henderson

2006-08-01

Full Text Available A subset of invasive alien plant species in southern Africa was analysed in terms of their history of introduction, rate of spread, countries/region of origin, taxonomy, growth forms, cultivated uses, weed status and current distribution in southern Africa, and comparisons made of those originating from south of the tropic of Capricorn, north of the tropic of Cancer and from the tropics. The subset of 233 species, belonging to 58 families, includes all important declared species and some potentially important species. Almost as many species originate from temperate regions (112 as from the tropics (121. Most southern temperate species came from Australia (28/36, most tropical species from tropical America (92/121 and most northern temperate species from Europe (including the Mediterranean and Asia (58/76. Transformers account for 33% of  all species. More transformers are of tropical origin (36 than of northern temperate (24 and southern temperate origin (18. However. 50% of southern temperate species are transformers, compared to 32% of northern temperate and 29% of tropical species. Southern temperate transformer species are mainly woody trees and shrubs that were established on a grand scale as silvicultural crops, barriers (hedges, windbreaks and screens and cover/binders. Most aquatics, herbs, climbers and succulent shrubs an. trom the tropics. Ornamentals are the single largest category of plants from all three regions, the tropics having contributed twice as many species as temperate regions.

Effect of feeding some evergreen tropical browse plant leaves on ...

African Journals Online (AJOL)

A feeding trial was conducted with thirty (30) weaner rabbits to investigate the nutritive potentials of some evergreen tropical browse plant leaves (Ficcus thoningii, Vitex doniana, Daniela oliveri, Sarcocephalus latifolia). Mixed breed rabbits were used and randomly assigned to five (5) treatments (T1 - T5). The rabbits in ...

Accuracy and simultaneous selection gains for N-stress tolerance and N-use efficiency in maize tropical lines

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Leandro de Freitas Mendonça

Full Text Available ABSTRACT Maize plants can be N-use efficient or N-stress tolerant. The first have high yields in favorable environments but is drastically affected under stress conditions; whereas the second show satisfactory yields in stressful environments but only moderate ones under optimal conditions. In this context, our aim was to assess the possibility of selecting tropical maize lines that are simultaneously N-stress tolerant and N-use efficient and check for differences between simultaneous selection statistical methods. Sixty-four tropical maize lines were evaluated for Nitrogen Agronomic Efficiency (NAE and Low Nitrogen Tolerance (LNTI response indices and two per se selection indices, Low Nitrogen Agronomic Efficiency (LNAE and Harmonic Mean of Relative Performance (HMRP. We performed eight selection scenarios: LNAE; HMRP; Additive index; Mulamba-Mock index; and Independent culling levels. The last three was predicted by REML/BLUP single-trait and multi-trait using genotypic values of NAE and LNTI. The REML/BLUP multi-trait analysis was superior to the single-trait analysis due to high unfavorable correlation between NAE and LNTI. However, the accuracy and genotypic determination coefficient of NAE and LNTI were too low. Thus, neither single- nor multi-trait analysis achieved a good result for simultaneous selection nor N-use efficiency nor N-stress tolerance. LNAE obtained satisfactorily accurate values and genotypic determination coefficient, but its performance in selection gain was worse than HMRP, particularly in terms of N-use efficiency. Therefore, because of the superior performance in accuracy, genotypic determination coefficient and selection, HMRP was considered the best simultaneous selection methodology of the scenarios tested for N-use efficiency and N-stress tolerance.

Nectar-living yeasts of a tropical host plant community: diversity and effects on community-wide floral nectar traits

Science.gov (United States)

2017-01-01

We characterize the diversity of nectar-living yeasts of a tropical host plant community at different hierarchical sampling levels, measure the associations between yeasts and nectariferous plants, and measure the effect of yeasts on nectar traits. Using a series of hierarchically nested sampling units, we extracted nectar from an assemblage of host plants that were representative of the diversity of life forms, flower shapes, and pollinator types in the tropical area of Yucatan, Mexico. Yeasts were isolated from single nectar samples; their DNA was identified, the yeast cell density was estimated, and the sugar composition and concentration of nectar were quantified using HPLC. In contrast to previous studies from temperate regions, the diversity of nectar-living yeasts in the plant community was characterized by a relatively high number of equally common species with low dominance. Analyses predict highly diverse nectar yeast communities in a relatively narrow range of tropical vegetation, suggesting that the diversity of yeasts will increase as the number of sampling units increases at the level of the species, genera, and botanical families of the hosts. Significant associations between specific yeast species and host plants were also detected; the interaction between yeasts and host plants impacted the effect of yeast cell density on nectar sugars. This study provides an overall picture of the diversity of nectar-living yeasts in tropical host plants and suggests that the key factor that affects the community-wide patterns of nectar traits is not nectar chemistry, but rather the type of yeasts interacting with host plants. PMID:28717591

Nectar-living yeasts of a tropical host plant community: diversity and effects on community-wide floral nectar traits

Directory of Open Access Journals (Sweden)

Azucena Canto

2017-07-01

Full Text Available We characterize the diversity of nectar-living yeasts of a tropical host plant community at different hierarchical sampling levels, measure the associations between yeasts and nectariferous plants, and measure the effect of yeasts on nectar traits. Using a series of hierarchically nested sampling units, we extracted nectar from an assemblage of host plants that were representative of the diversity of life forms, flower shapes, and pollinator types in the tropical area of Yucatan, Mexico. Yeasts were isolated from single nectar samples; their DNA was identified, the yeast cell density was estimated, and the sugar composition and concentration of nectar were quantified using HPLC. In contrast to previous studies from temperate regions, the diversity of nectar-living yeasts in the plant community was characterized by a relatively high number of equally common species with low dominance. Analyses predict highly diverse nectar yeast communities in a relatively narrow range of tropical vegetation, suggesting that the diversity of yeasts will increase as the number of sampling units increases at the level of the species, genera, and botanical families of the hosts. Significant associations between specific yeast species and host plants were also detected; the interaction between yeasts and host plants impacted the effect of yeast cell density on nectar sugars. This study provides an overall picture of the diversity of nectar-living yeasts in tropical host plants and suggests that the key factor that affects the community-wide patterns of nectar traits is not nectar chemistry, but rather the type of yeasts interacting with host plants.

Assessment of Plant Functional Types in Tropical Arid and Semi-Arid Ecosystems of India Using Remote Sensing Data and GIS

Science.gov (United States)

Sudhakar Reddy, C.; Krishna, P. Hari; Murthy, M. S. R.

2011-09-01

vegetation systems were studied along arid, semi-arid and sub-humid regions of Indian Desert and Aravallis of Rajasthan, India, with a distance of 600 km. The annual precipitation decreases from as high as 1600 mm in the south to 700 mm in the north-east and 100 mm in the west. The study is based on the integrated approach of remote sensing, GIS, and phytosociology. In the step 1, vegetation type map was prepared using multi-season IRS P6 LISS III data. Screening of plant traits was done based on field observations and literature. Phytosociological data pertains to 500 sample plots was used to identify plant functional traits of 900 species at morphological level. The vegetation classification scheme at regional level identified thorn forest, dry deciduous forest, broad leaved forest, woodland, shrubland and grasslands. Five plant traits selected in the study were significant for tropical environments. Attributes such as leaf size, leaf texture, spinescence, stem diameter and bark consistency were categorized systematically. Ordination analysis was carried out across the environmental gradient. Plant functional traits were measured on 20 individuals per species at each site. Environmental information was integrated to identify plant trait response. The spatial trends in PFTs were analysed and compared across the vegetation types, along the gradient of land surface temperature, climate, elevation and time integrated NDVI. Results established the occurrence of recurrent patterns of association among selected plant traits. Functional response groups were identified by summarizing results and relating them to individual species. Finally phytoclimatic map was prepared to represent spatial distribution of PFTs. The species with of functional traits of representing microphylls, sclerophyll, rough bark, spinescence and therophyte are demarcated as drought tolerant traits. Drought Intolerant PFTs are represented by macrophyll, malacophyll, smooth Bark, non spinescent stems and leaves

Methyl halide fluxes from tropical plants under controlled radiation and temperature regimes

Science.gov (United States)

Blei, Emanuel; Yokouchi, Yoko; Saito, Takuya; Nozoe, Susumu

2015-04-01

Methyl halides (CH3Cl, CH3Br, CH3I) contribute significantly to the halogen burden of the atmosphere and have the potential to influence the stratospheric ozone layer through their catalytic effect in the Chapman cycle. As such they have been studied over the years, and many plants and biota have been examined for their potential to act as a source of these gases. One of the potentially largest terrestrial sources identified was tropical vegetation such as tropical ferns and Dipterocarp trees. Most of these studies concentrated on the identification and quantification of such fluxes rather than their characteristics and often the chambers used in these studies were either opaque or only partially transparent to the full solar spectrum. Therefore it is not certain to which degree emissions of methyl halides are innate to the plants and how much they might vary due to radiation or temperature conditions inside the enclosures. In a separate development it had been proposed that UV-radiation could cause live plant materials to be become emitters of methane even under non-anoxic conditions. As methane is chemically very similar to methyl halides and had been proposed to be produced from methyl-groups ubiquitously found in plant cell material there is a relatively good chance that such a production mechanism would also apply to methyl halides. To test whether radiation can affect elevated emissions of methyl halides from plant materials and to distinguish this from temperature effects caused by heat build-up in chambers a set of controlled laboratory chamber enclosures under various radiation and temperature regimes was conducted on four different tropical plant species (Magnolia grandiflora, Cinnamonum camphora, Cyathea lepifera, Angiopteris lygodiifolia), the latter two of which had previously been identified as strong methyl halide emitters. Abscised leaf samples of these species were subjected to radiation treatments such UV-B, UV-A and broad spectrum radiation

Contrasting taxonomic and functional responses of a tropical tree community to selective logging

OpenAIRE

Baraloto, C.; Hérault, B.; Paine, C. E. T.; Massot, H.; Blanc, L.; Bonal, D.; Molino, Jean-François; Nicolini, E. A.; Sabatier, Daniel

2012-01-01

1. Considerable debate surrounds the extent to which tropical forests can be managed for resource extraction while conserving biodiversity and ecosystem properties, which depend on functional composition. Here we evaluate the compatibility of these aims by examining the effects of logging on taxonomic and functional diversity and composition in a tropical forest. 2. Twenty years after selective logging, we inventoried 4140 stems regenerating in logging gaps and adjacent undisturbed areas, and...

Polycyclic selection system for the tropical rainforests of northern Australia

Science.gov (United States)

Glen T. Dale; Grahame B. Applegate

1992-01-01

The polycyclic selection logging system developed and practiced for many years in the tropical rainforests of north Queensland has been successful in integrating timber production with the protection of conservation values. The system has been used by the Queensland Forest Service to manage north Queensland rainforests. The Queensland system has considerable potential...

Genomics approaches to unlock the high yield potential of cassava, a tropical model plant

Directory of Open Access Journals (Sweden)

Shengkui ZHANG,Ping'an MA,Haiyan WANG,Cheng LU,Xin CHEN,Zhiqiang XIA,Meiling ZOU,Xinchen ZHOU,Wenquan WANG

2014-12-01

Full Text Available Cassava, a tropical food, feed and biofuel crop, has great capacity for biomass accumulation and an extraordinary efficiency in water use and mineral nutrition, which makes it highly suitable as a model plant for tropical crops. However, the understanding of the metabolism and genomics of this important crop is limited. The recent breakthroughs in the genomics of cassava, including whole-genome sequencing and transcriptome analysis, as well as advances in the biology of photosynthesis, starch biosynthesis, adaptation to drought and high temperature, and resistance to virus and bacterial diseases, are reviewed here. Many of the new developments have come from comparative analyses between a wild ancestor and existing cultivars. Finally, the current challenges and future potential of cassava as a model plant are discussed.

Biohydrogen Production from Hydrolysates of Selected Tropical Biomass Wastes with Clostridium Butyricum

Science.gov (United States)

Dan Jiang; Fang, Zhen; Chin, Siew-Xian; Tian, Xiao-Fei; Su, Tong-Chao

2016-06-01

Biohydrogen production has received widespread attention from researchers in industry and academic fields. Response surface methodology (RSM) was applied to evaluate the effects of several key variables in anaerobic fermentation of glucose with Clostridium butyrium, and achieved the highest production rate and yield of hydrogen. Highest H2 yield of 2.02 mol H2/mol-glucose was achieved from 24 h bottle fermentation of glucose at 35 °C, while the composition of medium was (g/L): 15.66 glucose, 6.04 yeast extract, 4 tryptone, 3 K2HPO4, 3 KH2PO4, 0.05 L-cysteine, 0.05 MgSO4·7H2O, 0.1 MnSO4·H2O and 0.3 FeSO4·7H2O, which was very different from that for cell growth. Sugarcane bagasse and Jatropha hulls were selected as typical tropical biomass wastes to produce sugars via a two-step acid hydrolysis for hydrogen production. Under the optimized fermentation conditions, H2 yield (mol H2/mol-total reducing sugar) was 2.15 for glucose, 2.06 for bagasse hydrolysate and 1.95 for Jatropha hull hydrolysate in a 3L fermenter for 24 h at 35 °C, with H2 purity of 49.7-64.34%. The results provide useful information and basic data for practical use of tropical plant wastes to produce hydrogen.

Tropical Glaciers

Science.gov (United States)

Fountain, Andrew

The term "tropical glacier" calls to mind balmy nights and palm trees on one hand and cold, blue ice on the other. Certainly author Gabriel Garcia Marqez exploited this contrast in One Hundred Years of Solitude. We know that tropical fish live in warm, Sun-kissed waters and tropical plants provide lush, dense foliage populated by colorful tropical birds. So how do tropical glaciers fit into this scene? Like glaciers everywhere, tropical glaciers form where mass accumulation—usually winter snow—exceeds mass loss, which is generally summer melt. Thus, tropical glaciers exist at high elevations where precipitation can occur as snowfall exceeds melt and sublimation losses, such as the Rwenzori Mountains in east Africa and the Maoke Range of Irian Jaya.

Tree planting by small producers in the tropics: A comparative study of Brazil and Panama.

Science.gov (United States)

Cynthia S. Simmons; Robert T. Walker; Charles H. Wood

2002-01-01

Forest regrowth is a notable phenomenon across the tropical forest latitudes. Such reforestation takes place in the wake of land abandonment, occurs cyclically in a rotational agricultural system, and may result from the deliberate planting of trees by farmers. Although less extensive than successional forest regeneration, tree planting by small farmers can have...

Cooling performance assessment of horizontal earth tube system and effect on planting in tropical greenhouse

International Nuclear Information System (INIS)

Mongkon, S.; Thepa, S.; Namprakai, P.; Pratinthong, N.

2014-01-01

Graphical abstract: - Highlights: • The cooling ability of HETS is studied for planting in tropical greenhouse. • The effective of system was moderate with COP more than 2.0. • Increasing diameter and air velocity increase COP more than other parameters. • The plant growth with HETS was significantly better than no-HETS plant. - Abstract: The benefit of geothermal energy is used by the horizontal earth tube system (HETS); which is not prevalent in tropical climate. This study evaluated geothermal cooling ability and parameters studied in Thailand by mathematical model. The measurement of the effect on plant cultivation was carried out in two identical greenhouses with 30 m 2 of greenhouse volume. The HETS supplied cooled air to the model greenhouse (MGH), and the plant growth results were compared to the growth results of a conventional greenhouse (CGH). The prediction demonstrated that the coefficient of performance (COP) in clear sky day would be more than 2.0 while in the experiment it was found to be moderately lower. The parameters study could be useful for implementation of a system for maximum performance. Two plants Dahlias and head lettuce were grown satisfactory. The qualities of the plants with the HETS were better than the non-cooled plants. In addition, the quality of production was affected by variations of microclimate in the greenhouses and solar intensity throughout the cultivation period

An exceptional role for flowering plant physiology in the expansion of tropical rainforests and biodiversity.

Science.gov (United States)

Boyce, C Kevin; Lee, Jung-Eun

2010-11-22

Movement of water from soil to atmosphere by plant transpiration can feed precipitation, but is limited by the hydraulic capacities of plants, which have not been uniform through time. The flowering plants that dominate modern vegetation possess transpiration capacities that are dramatically higher than any other plants, living or extinct. Transpiration operates at the level of the leaf, however, and how the impact of this physiological revolution scales up to the landscape and larger environment remains unclear. Here, climate modelling demonstrates that angiosperms help ensure aseasonally high levels of precipitation in the modern tropics. Most strikingly, replacement of angiosperm with non-angiosperm vegetation would result in a hotter, drier and more seasonal Amazon basin, decreasing the overall area of ever-wet rainforest by 80 per cent. Thus, flowering plant ecological dominance has strongly altered climate and the global hydrological cycle. Because tropical biodiversity is closely tied to precipitation and rainforest area, angiosperm climate modification may have promoted diversification of the angiosperms themselves, as well as radiations of diverse vertebrate and invertebrate animal lineages and of epiphytic plants. Their exceptional potential for environmental modification may have contributed to divergent responses to similar climates and global perturbations, like mass extinctions, before and after angiosperm evolution.

Do tropical wetland plants possess a convective gas flow mechanism?

DEFF Research Database (Denmark)

Jensen, Dennis Konnerup; Sorrell, Brian Keith; Brix, Hans

2011-01-01

Internal pressurization and convective gas flow, which can aerate wetland plants more efficiently than diffusion, are common in temperate species. Here, we present the first survey of convective flow in a range of tropical plants. The occurrence of pressurization and convective flow was determined...... in 20 common wetland plants from the Mekong Delta in Vietnam. The diel variation in pressurization in culms and the convective flow and gas composition from stubbles were examined for Eleocharis dulcis, Phragmites vallatoria and Hymenachne acutigluma, and related to light, humidity and air temperature....... Nine of the 20 species studied were able to build up a static pressure of >50Pa, and eight species had convective flow rates higher than 1mlmin-1. There was a clear diel variation, with higher pressures and flows during the day than during the night, when pressures and flows were close to zero...

Volatile isoprenoids as defense compounds during abiotic stress in tropical plants

Science.gov (United States)

Jardine, K.

2015-12-01

Emissions of volatile isoprenoids from tropical forests play central roles in atmospheric processes by fueling atmospheric chemistry resulting in modified aerosol and cloud lifecycles and their associated feedbacks with the terrestrial biosphere. However, the identities of tropical isoprenoids, their biological and environmental controls, and functions within plants and ecosystems remain highly uncertain. As part of the DOE ARM program's GoAmazon 2014/15 campaign, extensive field and laboratory observations of volatile isoprenoids are being conducted in the central Amazon. Here we report the results of our completed and ongoing activities at the ZF2 forest reserve in the central Amazon. Among the results of the research are the suprisingly high abundance of light-dependent volatile isoprenoid emissions across abundant tree genera in the Amazon in both primary and secondary forests, the discovery of highly reactive monoterpene emissions from Amazon trees, and evidence for the importance of volatile isoprenoids in protecting photosynthesis during oxidative stress under elevated temperatures including energy consumption and direct antioxidant functions and a tight connection betwen volatile isoprenoid emissions, photorespiration, and CO2 recycling within leaves. The results highlight the need to model allocation of carbon to isoprenoids during elevated temperature stress in the tropics.

L’escalfament global i l’extinció de les plantes: un exemple tropical

OpenAIRE

Safont, Elisabet; Rull, Valentí; Vegas-Vilarrúbia, Teresa; Nogué, Sandra

2011-01-01

[EN]Global warminG and plant extinction: a tropical example. – Pantepui is a phytogeographical province made up of a group of approximately 50 tabular mountain summits or tepuis in southeast Venezuela. This region lies between 1500 and 3014 m a.s.l and covers an approximate area of 6000 km2. Its pristine state of conservation is remarkable. The summits of the tepuis contain an excep- tional level of vascular plant diversity, including 2446 known species, of which 771 are endemic t...

Plant litter dynamics in the forest-stream interface: precipitation is a major control across tropical biomes.

Science.gov (United States)

Tonin, Alan M; Gonçalves, José F; Bambi, Paulino; Couceiro, Sheyla R M; Feitoza, Lorrane A M; Fontana, Lucas E; Hamada, Neusa; Hepp, Luiz U; Lezan-Kowalczuk, Vânia G; Leite, Gustavo F M; Lemes-Silva, Aurea L; Lisboa, Leonardo K; Loureiro, Rafael C; Martins, Renato T; Medeiros, Adriana O; Morais, Paula B; Moretto, Yara; Oliveria, Patrícia C A; Pereira, Evelyn B; Ferreira, Lidiane P; Pérez, Javier; Petrucio, Mauricio M; Reis, Deusiano F; S Rezende, Renan; Roque, Nadia; Santos, Luiz E P; Siegloch, Ana E; Tonello, Gabriela; Boyero, Luz

2017-09-07

Riparian plant litter is a major energy source for forested streams across the world and its decomposition has repercussions on nutrient cycling, food webs and ecosystem functioning. However, we know little about plant litter dynamics in tropical streams, even though the tropics occupy 40% of the Earth's land surface. Here we investigated spatial and temporal (along a year cycle) patterns of litter inputs and storage in multiple streams of three tropical biomes in Brazil (Atlantic forest, Amazon forest and Cerrado savanna), predicting major differences among biomes in relation to temperature and precipitation regimes. Precipitation explained most of litter inputs and storage, which were generally higher in more humid biomes (litterfall: 384, 422 and 308 g m -2 y -1 , storage: 55, 113 and 38 g m -2 , on average in Atlantic forest, Amazon and Cerrado, respectively). Temporal dynamics varied across biomes in relation to precipitation and temperature, with uniform litter inputs but seasonal storage in Atlantic forest streams, seasonal inputs in Amazon and Cerrado streams, and aseasonal storage in Amazon streams. Our findings suggest that litter dynamics vary greatly within the tropics, but point to the major role of precipitation, which contrasts with the main influence of temperature in temperate areas.

Evolution of associations between Cymothoe butterflies and their Rinorea host plants in tropical Africa

NARCIS (Netherlands)

Velzen, van R.

2013-01-01

This thesis aimed to elucidate the evolutionary history of the associations between Cymothoeforest butterflies (Nymphalidae, Limenitidinae) and their Rinoreahost plants (Violaceae) in tropical Africa. Insects are by far the most diverse group of multicellular organisms on

Insecticide dissipation from soil and plant surfaces in tropical horticulture of southern Benin, West Africa.

Science.gov (United States)

Rosendahl, Ingrid; Laabs, Volker; Atcha-Ahowé, Cyrien; James, Braima; Amelung, Wulf

2009-06-01

In Sub-Saharan Africa, horticulture provides livelihood opportunities for millions of people, especially in urban and peri-urban areas. Although the vegetable agroecosystems are often characterized by intensive pesticide use, risks resulting therefrom are largely unknown under tropical horticultural conditions. The objective of this study therefore was to study the fate of pesticides in two representative horticultural soils (Acrisol and Arenosol) and plants (Solanum macrocarpon L.) after field application and thus to gain first insight on environmental persistence and dispersion of typical insecticides used in vegetable horticulture in Benin, West Africa. On plant surfaces, dissipation was rapid with half lives ranging from 2 to 87 h (alpha-endosulfan < beta-endosulfan < deltamethrin). Soil dissipation was considerably slower than dissipation from plant surfaces with half-lives ranging from 3 (diazinon) to 74 d (total endosulfan), but persistence of pesticides in soil was still reduced compared to temperate climates. Nevertheless, for deltamethrin and endosulfan, a tendency for mid-term accumulation in soil upon repeated applications was observed. The soil and plant surface concentrations of the metabolite endosulfan sulfate increased during the entire trial period, indicating that this compound is a potential long-term pollutant even in tropical environments.

Potential link between plant and fungal distributions in a dipterocarp rainforest: community and phylogenetic structure of tropical ectomycorrhizal fungi across a plant and soil ecotone.

Science.gov (United States)

Peay, Kabir G; Kennedy, Peter G; Davies, Stuart J; Tan, Sylvester; Bruns, Thomas D

2010-01-01

*Relatively little is known about diversity or structure of tropical ectomycorrhizal communities or their roles in tropical ecosystem dynamics. In this study, we present one of the largest molecular studies to date of an ectomycorrhizal community in lowland dipterocarp rainforest. *We sampled roots from two 0.4 ha sites located across an ecotone within a 52 ha forest dynamics plot. Our plots contained > 500 tree species and > 40 species of ectomycorrhizal host plants. Fungi were identified by sequencing ribosomal RNA genes. *The community was dominated by the Russulales (30 species), Boletales (17), Agaricales (18), Thelephorales (13) and Cantharellales (12). Total species richness appeared comparable to molecular studies of temperate forests. Community structure changed across the ecotone, although it was not possible to separate the role of environmental factors vs host plant preferences. Phylogenetic analyses were consistent with a model of community assembly where habitat associations are influenced by evolutionary conservatism of functional traits within ectomycorrhizal lineages. *Because changes in the ectomycorrhizal fungal community parallel those of the tree community at this site, this study demonstrates the potential link between the distribution of tropical tree diversity and the distribution of tropical ectomycorrhizal diversity in relation to local-scale edaphic variation.

Studies on saponin production in tropical medicinal plants Maesa argentea and Maesa lanceolata

Science.gov (United States)

Faizal, Ahmad; Geelen, Danny

2015-09-01

The continuous need for new compounds with important medicinal activities has lead to the identification and characterization of various plant-derived natural products. As a part of this program, we studied the saponin production from two tropical medicinal plants Maesa argentea and M. lanceolata and evaluated several treatments to enhance their saponin production. In this experiment, we present the analyses of saponin production from greenhouse grown plants by means of TLC and HPLC-MS. We observed that the content of saponin from these plants varied depending on organ and physiological age of the plants. In addition, the impact of elicitors on saponin accumulation on in vitro grown plants was analyzed using TLC. The production of saponin was very stable and not affected by treatment with methyl jasmonate, and salicylic acid. In conclusion, Maesa saponins are constitutively produced in plants and the level of these compounds in plants is mainly affected by the developmental or physiological stage.

Does selective logging stress tropical forest invertebrates? Using fat stores to examine sublethal responses in dung beetles.

Science.gov (United States)

França, Filipe; Barlow, Jos; Araújo, Bárbara; Louzada, Julio

2016-12-01

The increased global demand for tropical timber has driven vast expanses of tropical forests to be selectively logged worldwide. While logging impacts on wildlife are predicted to change species distribution and abundance, the underlying physiological responses are poorly understood. Although there is a growing consensus that selective logging impacts on natural populations start with individual stress-induced sublethal responses, this literature is dominated by investigations conducted with vertebrates from temperate zones. Moreover, the sublethal effects of human-induced forest disturbance on tropical invertebrates have never been examined. To help address this knowledge gap, we examined the body fat content and relative abundance of three dung beetle species (Coleoptera: Scarabaeinae) with minimum abundance of 40 individuals within each examined treatment level. These were sampled across 34 plots in a before-after control-impact design (BACI) in a timber concession area of the Brazilian Amazon. For the first time, we present evidence of logging-induced physiological stress responses in tropical invertebrates. Selective logging increased the individual levels of fat storage and reduced the relative abundance of two dung beetle species. Given this qualitative similarity, we support the measurement of body fat content as reliable biomarker to assess stress-induced sublethal effects on dung beetles. Understanding how environmental modification impacts the wildlife has never been more important. Our novel approach provides new insights into the mechanisms through which forest disturbances impose population-level impacts on tropical invertebrates.

Maize, tropical (Zea mays L.).

Science.gov (United States)

Assem, Shireen K

2015-01-01

Maize (Zea mays L.) is the third most important food crop globally after wheat and rice. In sub-Saharan Africa, tropical maize has traditionally been the main staple of the diet; 95 % of the maize grown is consumed directly as human food and as an important source of income for the resource-poor rural population. The biotechnological approach to engineer biotic and abiotic traits implies the availability of an efficient plant transformation method. The production of genetically transformed plants depends both on the ability to integrate foreign genes into target cells and the efficiency with which plants are regenerated. Maize transformation and regeneration through immature embryo culture is the most efficient system to regenerate normal transgenic plants. However, this system is highly genotype dependent. Genotypes adapted to tropic areas are difficult to regenerate. Therefore, transformation methods used with model genotypes adapted to temperate areas are not necessarily efficient with tropical lines. Agrobacterium-mediated transformation is the method of choice since it has been first achieved in 1996. In this report, we describe a transformation method used successfully with several tropical maize lines. All the steps of transformation and regeneration are described in details. This protocol can be used with a wide variety of tropical lines. However, some modifications may be needed with recalcitrant lines.

Automated classification of tropical shrub species: a hybrid of leaf shape and machine learning approach.

Science.gov (United States)

Murat, Miraemiliana; Chang, Siow-Wee; Abu, Arpah; Yap, Hwa Jen; Yong, Kien-Thai

2017-01-01

Plants play a crucial role in foodstuff, medicine, industry, and environmental protection. The skill of recognising plants is very important in some applications, including conservation of endangered species and rehabilitation of lands after mining activities. However, it is a difficult task to identify plant species because it requires specialized knowledge. Developing an automated classification system for plant species is necessary and valuable since it can help specialists as well as the public in identifying plant species easily. Shape descriptors were applied on the myDAUN dataset that contains 45 tropical shrub species collected from the University of Malaya (UM), Malaysia. Based on literature review, this is the first study in the development of tropical shrub species image dataset and classification using a hybrid of leaf shape and machine learning approach. Four types of shape descriptors were used in this study namely morphological shape descriptors (MSD), Histogram of Oriented Gradients (HOG), Hu invariant moments (Hu) and Zernike moments (ZM). Single descriptor, as well as the combination of hybrid descriptors were tested and compared. The tropical shrub species are classified using six different classifiers, which are artificial neural network (ANN), random forest (RF), support vector machine (SVM), k-nearest neighbour (k-NN), linear discriminant analysis (LDA) and directed acyclic graph multiclass least squares twin support vector machine (DAG MLSTSVM). In addition, three types of feature selection methods were tested in the myDAUN dataset, Relief, Correlation-based feature selection (CFS) and Pearson's coefficient correlation (PCC). The well-known Flavia dataset and Swedish Leaf dataset were used as the validation dataset on the proposed methods. The results showed that the hybrid of all descriptors of ANN outperformed the other classifiers with an average classification accuracy of 98.23% for the myDAUN dataset, 95.25% for the Flavia dataset and 99

Automated classification of tropical shrub species: a hybrid of leaf shape and machine learning approach

Directory of Open Access Journals (Sweden)

Miraemiliana Murat

2017-09-01

Full Text Available Plants play a crucial role in foodstuff, medicine, industry, and environmental protection. The skill of recognising plants is very important in some applications, including conservation of endangered species and rehabilitation of lands after mining activities. However, it is a difficult task to identify plant species because it requires specialized knowledge. Developing an automated classification system for plant species is necessary and valuable since it can help specialists as well as the public in identifying plant species easily. Shape descriptors were applied on the myDAUN dataset that contains 45 tropical shrub species collected from the University of Malaya (UM, Malaysia. Based on literature review, this is the first study in the development of tropical shrub species image dataset and classification using a hybrid of leaf shape and machine learning approach. Four types of shape descriptors were used in this study namely morphological shape descriptors (MSD, Histogram of Oriented Gradients (HOG, Hu invariant moments (Hu and Zernike moments (ZM. Single descriptor, as well as the combination of hybrid descriptors were tested and compared. The tropical shrub species are classified using six different classifiers, which are artificial neural network (ANN, random forest (RF, support vector machine (SVM, k-nearest neighbour (k-NN, linear discriminant analysis (LDA and directed acyclic graph multiclass least squares twin support vector machine (DAG MLSTSVM. In addition, three types of feature selection methods were tested in the myDAUN dataset, Relief, Correlation-based feature selection (CFS and Pearson’s coefficient correlation (PCC. The well-known Flavia dataset and Swedish Leaf dataset were used as the validation dataset on the proposed methods. The results showed that the hybrid of all descriptors of ANN outperformed the other classifiers with an average classification accuracy of 98.23% for the myDAUN dataset, 95.25% for the Flavia

Potential for biotic resistance from herbivores to tropical and subtropical plant invasions in aquatic ecosystems

NARCIS (Netherlands)

Petruzella, A.; Grutters, B.M.C.; Thomaz, S.M.; Bakker, E.S.

2017-01-01

Invasions of tropical and subtropical aquatic plants threaten biodiversity and cause ecological and economic impacts worldwide. An urgent question is whether native herbivores are able to inhibit the spread of these alien species thus providing biotic resistance. The potential for biotic resistance

Phytoremediation potential and ecological and phenological changes of native pioneer plants from weathered oil spill-impacted sites at tropical wetlands.

Science.gov (United States)

Palma-Cruz, Felipe de J; Pérez-Vargas, Josefina; Rivera Casado, Noemí Araceli; Gómez Guzmán, Octavio; Calva-Calva, Graciano

2016-08-01

Pioneer native plant species from weathered oil spill-affected sites were selected to study their potential for phytoremediation on the basis of their ecological and phenological changes during the phytoremediation process. Experiments were conducted in field and in greenhouse. In field, native plants from aged oil spill-impacted sites with up 400 g of weathered petroleum hydrocarbons per kilogram soil were selected. In the impacted sites, the principal dominant plant species with potential for hydrocarbons removal were Cyperus laxus, Cyperus esculentus, and Ludwigia peploides. In greenhouse, the phenology of the selected plant species was drastically affected by the hydrocarbons level above 325 g total petroleum hydrocarbons (TPH) per kilogram soil after 2 years of phytoremediation of soils from the aged oil spill-impacted sites. From the phytoremediation treatments, a mix-culture of C. laxus, C. esculentus, and L. peploides in soil containing 325 g TPH/kg soil, from which 20.3 % were polyaromatic hydrocarbons (PAH) and 34.2 % were asphaltenes (ASF), was able to remove up 93 % of the TPH, while in unvegetated soil the TPH removal was 12.6 %. Furthermore, evaluation of the biodiversity and life forms of plant species in the impacted sites showed that phytoremediation with C. esculentus, alone or in a mix-culture with C. laxus and L. peploides, reduces the TPH to such extent that the native plant community was progressively reestablished by replacing the cultivated species resulting in the ecological recovery of the affected soil. These results demonstrate that native Cyperus species from weathered oil spill-affected sites, specifically C. esculentus and C. laxus, alone or in a mix-culture, have particular potential for phytoremediation of soils from tropical wetlands contaminated with weathered oil hydrocarbons.

The Species Richness of Vascular Plants and Amphibia in Major Plant Communities in Temperate to Tropical Australia: Relationship with Annual Biomass Production

International Nuclear Information System (INIS)

Specht, R. L.; Tyler, M.J.

2010-01-01

Aerodynamic fluxes (frictional, thermal, evaporative) in the atmosphere as it flows over and through a plant community determine the Foliage Projective Covers and eco-morphological attributes of new leaves developed annually in overstorey and understorey strata. The number of leaves produced on vertical foliage shoots depends on available soil water and nutrients, also ambient temperature, during this short growth season. Stem density (number of stems per hectare) and species richness (number of species per hectare) in the overstorey of major Floristic Groups are correlated with annual shoot growth (ASG, t ha-1) in that stratum. Species richness in the overstorey increases in the climatic gradient from the arid to the humid zone as well as with increasing air temperatures (about 10 degree C) from temperate to tropical Australia. Species richness in the understorey is highest in plant communities in temperate Australia, decreasing in the temperature gradient towards the tropics. As with other major plant and animal groups within an ecosystem, the species richness of Amphibia is correlated with the amount of solar energy fixed (per annum) by the major plant formation in the regional photosynthetic potential determined by the foliage shoots (ASG, t ha-1) produced annually in the overstorey.

The Species Richness of Vascular Plants and Amphibia in Major Plant Communities in Temperate to Tropical Australia: Relationship with Annual Biomass Production

Directory of Open Access Journals (Sweden)

R. L. Specht

2010-01-01

Full Text Available Aerodynamic fluxes (frictional, thermal, evaporative in the atmosphere as it flows over and through a plant community determine the Foliage Projective Covers and eco-morphological attributes of new leaves developed annually in overstorey and understorey strata. The number of leaves produced on vertical foliage shoots depends on available soil water and nutrients, also ambient temperature, during this short growth season. Stem density (number of stems per hectare and species richness (number of species per hectare in the overstorey of major Floristic Groups are correlated with annual shoot growth (ASG, t ha−1 in that stratum. Species richness in the overstorey increases in the climatic gradient from the arid to the humid zone as well as with increasing air temperatures (about 10oC from temperate to tropical Australia. Species richness in the understorey is highest in plant communities in temperate Australia, decreasing in the temperature gradient towards the tropics. As with other major plant and animal groups within an ecosystem, the species richness of Amphibia is correlated with the amount of solar energy fixed (per annum by the major plant formation in the region—a photosynthetic potential determined by the foliage shoots (ASG, t ha−1 produced annually in the overstorey.

Correlation between earthworms and plant litter decomposition in a tropical wet forest of Puerto Rico.

Science.gov (United States)

Jennifer Dechainea; Honghua Ruanb; Yaniria Sanchez-de Leon; Xiaoming Zou

2005-01-01

Earthworms are recognized to play an important role in the decomposition of organic materials. To test the use of earthworms as an indicator of plant litter decomposition, we examined the abundance and biomass of earthworms in relation to plant litter decomposition in a tropical wet forest of Puerto Rico. We collected earthworms at 0–0.1m and 0.1–0.25m soil depths from...

Experimental defoliation affects male but not female reproductive performance of the tropical monoecious plant Croton suberosus (Euphorbiaceae).

Science.gov (United States)

Narbona, Eduardo; Dirzo, Rodolfo

2010-08-01

Monoecious plants have the capacity to allocate resources separately to male and female functions more easily than hermaphrodites. This can be advantageous against environmental stresses such as leaf herbivory. However, studies showing effects of herbivory on male and female functions and on the interaction with the plant's pollinators are limited, particularly in tropical plants. Here, the effects of experimental defoliation were examined in the monoecious shrub Croton suberosus (Euphorbiaceae), a wasp-pollinated species from a Mexican tropical dry forest. Three defoliation treatments were applied: 0 % (control), 25 % (low) or 75 % (high) of plant leaf area removed. Vegetative (production of new leaves) and reproductive (pistillate and staminate flower production, pollen viability, nectar production, fruit set, and seed set) performance variables, and the abundance and activity of floral visitors were examined. Defoliated plants overcompensated for tissue loss by producing more new leaves than control plants. Production of staminate flowers gradually decreased with increasing defoliation and the floral sex ratio (staminate : pistillate flowers) was drastically reduced in high-defoliation plants. In contrast, female reproductive performance (pistillate flower production, fruit set and seed set) and pollinator visitation and abundance were not impacted by defoliation. The asymmetrical effects of defoliation on male and female traits of C. suberosus may be due to the temporal and spatial flexibility in the allocation of resources deployed by monoecious plants. We posit that this helps to maintain the plant's pollination success in the face of leaf herbivory stress.

Forest Fragmentation and Selective Logging Have Inconsistent Effects on Multiple Animal-Mediated Ecosystem Processes in a Tropical Forest

Science.gov (United States)

Schleuning, Matthias; Farwig, Nina; Peters, Marcell K.; Bergsdorf, Thomas; Bleher, Bärbel; Brandl, Roland; Dalitz, Helmut; Fischer, Georg; Freund, Wolfram; Gikungu, Mary W.; Hagen, Melanie; Garcia, Francisco Hita; Kagezi, Godfrey H.; Kaib, Manfred; Kraemer, Manfred; Lung, Tobias; Schaab, Gertrud; Templin, Mathias; Uster, Dana; Wägele, J. Wolfgang; Böhning-Gaese, Katrin

2011-01-01

Forest fragmentation and selective logging are two main drivers of global environmental change and modify biodiversity and environmental conditions in many tropical forests. The consequences of these changes for the functioning of tropical forest ecosystems have rarely been explored in a comprehensive approach. In a Kenyan rainforest, we studied six animal-mediated ecosystem processes and recorded species richness and community composition of all animal taxa involved in these processes. We used linear models and a formal meta-analysis to test whether forest fragmentation and selective logging affected ecosystem processes and biodiversity and used structural equation models to disentangle direct from biodiversity-related indirect effects of human disturbance on multiple ecosystem processes. Fragmentation increased decomposition and reduced antbird predation, while selective logging consistently increased pollination, seed dispersal and army-ant raiding. Fragmentation modified species richness or community composition of five taxa, whereas selective logging did not affect any component of biodiversity. Changes in the abundance of functionally important species were related to lower predation by antbirds and higher decomposition rates in small forest fragments. The positive effects of selective logging on bee pollination, bird seed dispersal and army-ant raiding were direct, i.e. not related to changes in biodiversity, and were probably due to behavioural changes of these highly mobile animal taxa. We conclude that animal-mediated ecosystem processes respond in distinct ways to different types of human disturbance in Kakamega Forest. Our findings suggest that forest fragmentation affects ecosystem processes indirectly by changes in biodiversity, whereas selective logging influences processes directly by modifying local environmental conditions and resource distributions. The positive to neutral effects of selective logging on ecosystem processes show that the

Incorporation of {sup 137}Cs by tropical tree species and its correlation with plant physiology

Energy Technology Data Exchange (ETDEWEB)

Cid, Alberto Silva; Anjos, Roberto Meigikos dos; Macario, K.D.; Veiga, R.; Ayubi, J. Juri; Lacerda, T. [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Instituto de Fisica; Zamboni, C.B.; Medeiros, I.M.A. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN- SP), Sao Paulo, SP (Brazil); Velasco, H.; Rizzotto, M. [Universidad Nacional de San Luis (UNSL) (Argentina). Instituto de Matematica Aplicada San Luis; Audicio, P. [Facultad de Ciencias (UDELAR), Montevideo (Uruguay). Centro de Investigaciones Nucleares

2011-07-01

Environmental phenomena associated with potential releases of radionuclides to terrestrial ecosystems have attracted the interest of several researches around the world. However, such interest has not been focused exclusively in its effects on human health. Several radionuclides have also been used as tracers of physicochemical or biological phenomena. These studies depend on both the development of auxiliary analysis techniques, which help to improve the results of traditional methods, and the production of additional data, so that a wide variety of natural processes can be understood. In this sense, the same radiometric results can be analyzed or interpreted from different viewpoints, allowing the interdisciplinary understanding of the overall structure of terrestrial ecosystems. {sup 137}Cs, for example, is one of the main fission products of nuclear reactors and atmospheric nuclear testing that is persistent in the biosphere because of its half-life of 30.2 years and biological mobility. This radionuclide remains in the top soil due to fixation and adsorption to clay minerals and organic matter, persisting in the root zone of plant for a long period of time. As its chemical behavior is similar to other monovalent inorganic cations (such as NH{sup +}{sub 4} , Na{sup +} and K{sup +}), Cs{sup +} can be readily absorbed by roots and translocated to the aboveground parts of plant. In this work, concentrations of {sup 137}Cs{sup +}, K{sup +} and Na{sup +} in fruits of lemon (Citrus limon B.) and coconut (Cocos nucifera L.) were measured by both gamma spectrometry and neutron activation analysis, with the aim to understand the behavior of monovalent inorganic cations in tropical plants as well as the plant ability to store these elements. In contrast to K{sup +} and Na{sup +}, Cs{sup +} is not an essential element to plants. However, our results have shown that {sup 137}Cs{sup +} incorporation to vegetal tissues is positively correlated to K{sup +} distribution inside

Effects of Nonnative Ungulate Removal on Plant Communities and Soil Biogeochemistry in Tropical Forests

Science.gov (United States)

Cole, R. J.; Litton, C. M.; Giardina, C. P.; Sparks, J. P.

2014-12-01

Non-native ungulates have substantial impacts on native ecosystems globally, altering both plant communities and soil biogeochemistry. Across tropical and temperate ecosystems, land managers fence and remove non-native ungulates to conserve native biodiversity, a costly management action, yet long-term outcomes are not well quantified. Specifically, knowledge gaps include: (i) the magnitude and time frame of plant community recovery; (ii) the response of non-native invasive plants; and (iii) changes to soil biogeochemistry. In 2010, we established a series of paired ungulate presence vs. removal plots that span a 20 yr. chronosequence in tropical montane wet forests on the Island of Hawaii to quantify the impacts and temporal legacy of feral pig removal on plant communities and soil biogeochemistry. We also compared soil biogeochemistry in targeted areas of low and high feral pig impact. Our work shows that both native and non-native vegetation respond positively to release from top-down control following removal of feral pigs, but species of high conservation concern recover only if initially present at the time of non-native ungulate removal. Feral pig impacts on soil biogeochemistry appear to last for at least 20 years following ungulate removal. We observed that both soil physical and chemical properties changed with feral pig removal. Soil bulk density and volumetric water content decreased while extractable base cations and inorganic N increased in low vs. high feral pig impact areas. We hypothesize that altered soil biogeochemistry facilitates continued invasions by non-native plants, even decades after non-native ungulate removal. Future work will concentrate on comparisons between wet and dry forest ecosystems and test whether manipulation of soil nutrients can be used to favor native vs. non-native plant establishment.

Early selection of elite plants in Asparagus

Directory of Open Access Journals (Sweden)

COINTRY ENRIQUE LUIS

2000-01-01

Full Text Available In order to establish an efficient selection criterion the variability in three asparagus populations was evaluated defining the most important yield components and analysing its evolution along three growing seasons. The yield components, coefficient of variation (CV and the proportion of plants contributing to 80% of the total yield were estimated. The elite plants were selected by mean of total yield and clusters techniques. Multiple regression showed that spear number (SN and spear weight (SW were the most important yield components. In every population, total yield (TY and SN showed the highest values of CV, independently of sex. 69% of the plants contributed to the 80% of the total yield in the first year while in the second and third year the contribution was 57%. At the end of the third year, 17 plants were selected by the average of the total yield and 43 by clusters. It is suggested to select for SW in the first year, reducing in 68% the experimental material. In the second year, the selection for SN would reduce to 5% the plants to evaluate for total yield in the third year. In this way the selected plants are the same but the number of plants to evaluate is dramatically reduced along the years, therefore facilitating the breeders work.

Assessment of Air Pollution Tolerance Index of some plants to develop vertical gardens near street canyons of a polluted tropical city.

Science.gov (United States)

Pandey, Ashutosh Kumar; Pandey, Mayank; Tripathi, B D

2016-12-01

The aim of the present study was to examine Air Pollution Tolerance Index (APTI) of some climber plant species to develop vertical gardens in Varanasi city which has characteristics of tall building and narrow roads. This condition results in street canyon like structure and hinders the vertical dispersal of air pollutants. We have selected 24 climber plant species which are commonly found in of Varanasi city. Chosen plants can be easily grown either in planter boxes or directly in the ground, with a vertical support they can climb on walls to form green walls or vertical garden. Air Pollution Tolerance Index (APTI) of the selected plant species was calculated and plants with higher APTI are recommended for the development of Vertical garden. Highest APTI was noted for Ipomoea palmata (25.39) followed by Aristolochia elegans (23.28), Thunbergia grandiflora (23.14), Quisqualis indica (22.42), and Clerodendrum splendens (22.36). However, lowest APTI value (8.75) was recorded for the species Hemidesmus indicus. Moreover, the linear regression analysis has revealed a high positive correlation between APTI and ascorbic acid content (R 2 =0.8837) and positive correlation between APTI and Chlorophyll content (R 2 =0.6687). On the basis of higher APTI values (greater than 17), nine species of climber plants viz. I. palmata, T. grandiflora, C. splendens, A. elegans, Q. indica, Petria volubilis, Antigonon leptopus, Cryptolepis buchuanni and Tinospora cordifolia have been recommended to develop vertical greenery systems in a compact tropical city. Copyright © 2015 Elsevier Inc. All rights reserved.

Design basis tropical cyclone for nuclear power plants

International Nuclear Information System (INIS)

1984-01-01

The general characteristics of tropical cyclones are discussed in this Safety Guide, with particular emphasis on their pressure and wind structures in the light of available data. General methods are given for the evaluation of the relevant parameters of a Probable Maximum Tropical Cyclone (PMTC), which can be used as the Design Basis Tropical Cyclone (DBTC); these parameters then serve as inputs for the derivation of a design basis surge and a design basis wind. A possible method is also given for the evaluation of the PMTC pressure and wind field based on an approach valid primarily for a particular region. This method depends on the results of a theoretical study on the tropical cyclone structure and makes use of a large amount of data, including aircraft reconnaissance observations for 170 most intense tropical cyclones near the coast of Japan, Taiwan and the Philippines for the period 1960-1974, as well as detailed analyses of all the extreme storms along the Gulf of Mexico and the east coast of the USA during 1900-1978, for the determination of the necessary parameters

Iron Availability in Tropical Soils and Iron Uptake by Plants

Directory of Open Access Journals (Sweden)

Guilherme Furlan Mielki

Full Text Available ABSTRACT Given the increase in crop yields and the expansion of agriculture in low fertility soils, deficiency of micronutrients, such as iron, in plants grown in tropical soils has been observed. The aim of this study was to evaluate Fe availability and Fe uptake by corn (Zea mays L. plants in 13 different soils, at two depths. Iron was extracted by Mehlich-1, Mehlich-3, and CaCl2 (Fe-CC and was fractionated in forms related to low (Feo and high (Fed crystallinity pedogenic oxyhydroxides, and organic matter (Fep using ammonium oxalate, dithionite-citrate, and sodium pyrophosphate, respectively. In order to relate Fe availability to soil properties and plant growth, an experiment was carried out in a semi-hydroponic system in which part of the roots developed in a nutrient solution (without Fe and part in the soil (the only source of Fe. Forty-five days after seeding, we quantified shoot dry matter and leaf Fe concentration and content. Fed levels were high, from 5 to 132 g kg-1, and Feo and Fe-CC levels were low, indicating the predominance of Fe as crystalline oxyhydroxides and a low content of Fe readily available to plants. The extraction solutions showed significant correlations with various soil properties, many common to both, indicating that they act similarly. The correlation between the Mehlich-1 and Mehlich-3 extraction solutions was highly significant. However, these two extraction methods were inefficient in predicting Fe availability to plants. There was a positive correlation between dry matter and Fe levels in plant shoots, even within the ranges considered adequate in the soil and in the plant. Dry matter production and leaf Fe concentration and content were positively correlated with Fep concentration, indicating that the Fe fraction related to soil organic matter most contributes to Fe availability to plants.

Stable carbon, oxygen, and nitrogen, isotope analysis of plants from a South Asian tropical forest: Implications for primatology.

Science.gov (United States)

Roberts, Patrick; Blumenthal, Scott A; Dittus, Wolfgang; Wedage, Oshan; Lee-Thorp, Julia A

2017-06-01

Stable isotope analysis of primate tissues in tropical forest contexts is an increasingly popular means of obtaining information about niche distinctions among sympatric species, including preferences in feeding height, forest canopy density, plant parts, and trophism. However, issues of equifinality mean that feeding height, canopy density, as well as the plant parts and plant species consumed, may produce similar or confounding effects. With a few exceptions, researchers have so far relied largely on general principles and/or limited plant data from the study area as references for deducing the predominant drivers of primate isotope variation. Here, we explore variation in the stable carbon (δ 13 C), nitrogen (δ 15 N), and oxygen (δ 18 O) isotope ratios of 288 plant samples identified as important to the three primate species from the Polonnaruwa Nature Sanctuary, Sri Lanka, relative to plant part, season, and canopy height. Our results show that plant part and height have the greatest effect on the δ 13 C and δ 18 O measurements of plants of immediate relevance to the primates, Macaca sinica, Semnopithecus priam thersites, and Trachypithecus vetulus, living in this monsoonal tropical forest. We find no influence of plant part, height or season on the δ 15 N of measured plants. While the plant part effect is particularly pronounced in δ 13 C between fruits and leaves, differential feeding height, and plant taxonomy influence plant δ 13 C and δ 18 O differences in addition to plant organ. Given that species composition in different regions and forest types will differ, the results urge caution in extrapolating general isotopic trends without substantial local baselines studies. © 2017 Wiley Periodicals, Inc.

Accumulation and long term behavior of radiocesium in tropical plants

Energy Technology Data Exchange (ETDEWEB)

Anjos, R.M.; Carvalho, C.; Mosquera, B.; Macario, K.; Veiga, R.; Sanches, N.; Bastos, J.; Saavedra, R.; Iguatemy, M. [Universidade Federal Fluminense, Niteroi (Brazil)

2006-07-01

Full text of publication follows: In recent years, there has been a growing interest in the evaluation of nutrient fluxes and radioactive contaminants in forest and agricultural ecosystems. Several studies on forest ecosystems have been carried out, mostly in Europe, after the Chernobyl accident. Japanese forest sites and native plant species of the Marshall Islands have also been extensively investigated. These studies have been used for various purposes, including the development of models for predicting plant concentrations from soil concentration measurements or the long term of dietary contamination by radiocesium following a fallout nuclear. Cesium is an alkali metal just like potassium and its behavior in nature, as well as in the human body, is similar to that of potassium. Uptake of 137 Cs from contaminated soil represents a significant pathway of human radiation exposure, either due to the direct consumption of cereals, fruits and vegetables or, indirectly, following consumption of milk and meat from animals fed on contaminated vegetable matter. The decline of 137 Cs levels as function of time of fruit trees is of interest given its long life in the field. Therefore, the cesium behavior is important in the design of management strategies to mitigate any negative health effects of radioactivity on the environment. It is also important to apply the current knowledge of the transport and distribution of salts derived from forest ecosystems in agricultural ecosystems, especially for tropical fruit trees. So far, in the South hemisphere there have been only a few studies on this subject, without conclusive results. With this aim, the Laboratory of Radioecology (L.A.R.A.) of the Universidade Federal Fluminense has been performing analyzes of 137 Cs and 40 K concentrations in several tropical plants (guava, mango, avocado, pomegranate, papaya, manioc and chili pepper trees) in order to determine the accumulation of these radionuclides throughout these trees and

Accumulation and long term behavior of radiocesium in tropical plants

International Nuclear Information System (INIS)

Anjos, R.M.; Carvalho, C.; Mosquera, B.; Macario, K.; Veiga, R.; Sanches, N.; Bastos, J.; Saavedra, R.; Iguatemy, M.

2006-01-01

Full text of publication follows: In recent years, there has been a growing interest in the evaluation of nutrient fluxes and radioactive contaminants in forest and agricultural ecosystems. Several studies on forest ecosystems have been carried out, mostly in Europe, after the Chernobyl accident. Japanese forest sites and native plant species of the Marshall Islands have also been extensively investigated. These studies have been used for various purposes, including the development of models for predicting plant concentrations from soil concentration measurements or the long term of dietary contamination by radiocesium following a fallout nuclear. Cesium is an alkali metal just like potassium and its behavior in nature, as well as in the human body, is similar to that of potassium. Uptake of 137 Cs from contaminated soil represents a significant pathway of human radiation exposure, either due to the direct consumption of cereals, fruits and vegetables or, indirectly, following consumption of milk and meat from animals fed on contaminated vegetable matter. The decline of 137 Cs levels as function of time of fruit trees is of interest given its long life in the field. Therefore, the cesium behavior is important in the design of management strategies to mitigate any negative health effects of radioactivity on the environment. It is also important to apply the current knowledge of the transport and distribution of salts derived from forest ecosystems in agricultural ecosystems, especially for tropical fruit trees. So far, in the South hemisphere there have been only a few studies on this subject, without conclusive results. With this aim, the Laboratory of Radioecology (L.A.R.A.) of the 'Universidade Federal Fluminense' has been performing analyzes of 137 Cs and 40 K concentrations in several tropical plants (guava, mango, avocado, pomegranate, papaya, manioc and chili pepper trees) in order to determine the accumulation of these radionuclides throughout these trees

Power plant fuel switching and air quality in a tropical, forested environment

Science.gov (United States)

Medeiros, Adan S. S.; Calderaro, Gisele; Guimarães, Patricia C.; Magalhaes, Mateus R.; Morais, Marcos V. B.; Rafee, Sameh A. A.; Ribeiro, Igor O.; Andreoli, Rita V.; Martins, Jorge A.; Martins, Leila D.; Martin, Scot T.; Souza, Rodrigo A. F.

2017-07-01

How a changing energy matrix for electricity production affects air quality is considered for an urban region in a tropical, forested environment. Manaus, the largest city in the central Amazon Basin of Brazil, is in the process of changing its energy matrix for electricity production from fuel oil and diesel to natural gas over an approximately 10-year period, with a minor contribution by hydropower. Three scenarios of urban air quality, specifically afternoon ozone concentrations, were simulated using the Weather Research and Forecasting (WRF-Chem) model. The first scenario used fuel oil and diesel for electricity production, which was the reality in 2008. The second scenario was based on the fuel mix from 2014, the most current year for which data were available. The third scenario considered nearly complete use of natural gas for electricity production, which is the anticipated future, possibly for 2018. For each case, inventories of anthropogenic emissions were based on electricity generation, refinery operations, and transportation. Transportation and refinery operations were held constant across the three scenarios to focus on effects of power plant fuel switching in a tropical context. The simulated NOx and CO emissions for the urban region decrease by 89 and 55 %, respectively, after the complete change in the energy matrix. The results of the simulations indicate that a change to natural gas significantly decreases maximum afternoon ozone concentrations over the population center, reducing ozone by > 70 % for the most polluted days. The sensitivity of ozone concentrations to the fuel switchover is consistent with a NOx-limited regime, as expected for a tropical forest having high emissions of biogenic volatile organic compounds, high water vapor concentrations, and abundant solar radiation. There are key differences in a shifting energy matrix in a tropical, forested environment compared to other world environments. Policies favoring the burning of

Power plant fuel switching and air quality in a tropical, forested environment

Directory of Open Access Journals (Sweden)

A. S. S. Medeiros

2017-07-01

Full Text Available How a changing energy matrix for electricity production affects air quality is considered for an urban region in a tropical, forested environment. Manaus, the largest city in the central Amazon Basin of Brazil, is in the process of changing its energy matrix for electricity production from fuel oil and diesel to natural gas over an approximately 10-year period, with a minor contribution by hydropower. Three scenarios of urban air quality, specifically afternoon ozone concentrations, were simulated using the Weather Research and Forecasting (WRF-Chem model. The first scenario used fuel oil and diesel for electricity production, which was the reality in 2008. The second scenario was based on the fuel mix from 2014, the most current year for which data were available. The third scenario considered nearly complete use of natural gas for electricity production, which is the anticipated future, possibly for 2018. For each case, inventories of anthropogenic emissions were based on electricity generation, refinery operations, and transportation. Transportation and refinery operations were held constant across the three scenarios to focus on effects of power plant fuel switching in a tropical context. The simulated NOx and CO emissions for the urban region decrease by 89 and 55 %, respectively, after the complete change in the energy matrix. The results of the simulations indicate that a change to natural gas significantly decreases maximum afternoon ozone concentrations over the population center, reducing ozone by > 70 % for the most polluted days. The sensitivity of ozone concentrations to the fuel switchover is consistent with a NOx-limited regime, as expected for a tropical forest having high emissions of biogenic volatile organic compounds, high water vapor concentrations, and abundant solar radiation. There are key differences in a shifting energy matrix in a tropical, forested environment compared to other world environments. Policies

Biotechnology in plant nutrient management for agricultural ...

African Journals Online (AJOL)

Biotechnology in plant nutrient management for agricultural production in the tropics: ... and yields, marker assisted selection breeding, to develop new uses for agricultural products, to facilitate early maturation and to improve food and feed ...

In vitro antiplasmodial, antileishmanial and antitrypanosomal activities of selected medicinal plants used in the traditional Arabian Peninsular region

Directory of Open Access Journals (Sweden)

Al-Musayeib Nawal M

2012-04-01

Full Text Available Abstract Background Worldwide particularly in developing countries, a large proportion of the population is at risk for tropical parasitic diseases. Several medicinal plants are still used traditionally against protozoal infections in Yemen and Saudi Arabia. Thus the present study investigated the in vitro antiprotozoal activity of twenty-five plants collected from the Arabian Peninsula. Methods Plant materials were extracted with methanol and screened in vitro against erythrocytic schizonts of Plasmodium falciparum, intracellular amastigotes of Leishmania infantum and Trypanosoma cruzi and free trypomastigotes of T. brucei. Cytotoxic activity was determined against MRC-5 cells to assess selectivity. The criterion for activity was an IC50 T. brucei and selectivity index of >4. Results Antiplasmodial activity was found in the extracts of Chrozophora oblongifolia, Ficus ingens, Lavandula dentata and Plectranthus barbatus. Amastigotes of T. cruzi were affected by Grewia erythraea, L. dentata, Tagetes minuta and Vernonia leopoldii. Activity against T. brucei was obtained in G. erythraea, L. dentata, P. barbatus and T. minuta. No relevant activity was found against L. infantum. High levels of cytotoxicity (MRC-5 IC50 Cupressus sempervirens, Kanahia laniflora and Kniphofia sumarae. Conclusion The results endorse that medicinal plants can be promising sources of natural products with antiprotozoal activity potential. The results support to some extent the traditional uses of some plants for the treatment of parasitic protozoal diseases.

Building a Plant DNA Barcode Reference Library for a Diverse Tropical Flora: An Example from Queensland, Australia

Directory of Open Access Journals (Sweden)

Craig M. Costion

2016-02-01

Full Text Available A foundation for a DNA barcode reference library for the tropical plants of Australia is presented here. A total of 1572 DNA barcode sequences are compiled from 848 tropical Queensland species. The dataset represents 35% of the total flora of Queensland’s Wet Tropics Bioregion, 57% of its tree species and 28% of the shrub species. For approximately half of the sampled species, we investigated the occurrence of infraspecific molecular variation in DNA barcode loci rbcLa, matK, and the trnH-psbA intergenic spacer region across previously recognized biogeographic barriers. We found preliminary support for the notion that DNA barcode reference libraries can be used as a tool for inferring biogeographic patterns at regional scales. It is expected that this dataset will find applications in taxonomic, ecological, and applied conservation research.

Nuclear power plant risk from tropical cyclones

International Nuclear Information System (INIS)

Gilmore, T.F.

1991-01-01

Tropical cyclones are considered to have a potential for contributing to the overall core-melt frequency at Turkey Point. A tropical cyclone is known to have the four main hazards associated with it: wind, tidal surge, wind-generated missiles, and precipitation. To understand the contribution to overall core-melt risk at Turkey Point, it is essential to understand the mechanisms of these hazards and their relative importance. The results are bounded by the hurricane surge scenario, where the frequency of core melt is equal to the frequency of the surge reaching 19 ft NGVD (National Geographic Vertical Datum). This could be mitigated by potential recovery actions for the tropical cyclone scenario. The probability of the storm surge reaching 19 ft NVGD is estimated to be 1 x 10 -4 . The data associated with the tropical cyclones as discussed in detail in the body of this paper are lacking in quantity and quality. By taking the conservative approach in creating the wind/frequency, wind/surge, and surge/frequency relationships, the conclusion that the results are worst case is reasonable. With this in mind, it is logical to conclude that the value of further hazard analysis to narrow down the built-in conservative margin using the existing data and technology is doubtful. Thus, a recovery approach to driving the risk level down is the most pragmatic step to be taken

Effective selection of transgenic papaya plants with the PMI/Man selection system.

Science.gov (United States)

Zhu, Yun J; Agbayani, Ricelle; McCafferty, Heather; Albert, Henrik H; Moore, Paul H

2005-09-01

The selectable marker gene phospho-mannose isomerase (pmi), which encodes the enzyme phospho-mannose isomerase (PMI) to enable selection of transformed cell lines on media containing mannose (Man), was evaluated for genetic transformation of papaya (Carica papaya L.). We found that papaya embryogenic calli have little or no PMI activity and cannot utilize Man as a carbon source; however, when calli were transformed with a pmi gene, the PMI activity was greatly increased and they could utilize Man as efficiently as sucrose. Plants regenerated from selected callus lines also exhibited PMI activity but at a lower specific activity level. Our transformation efficiency with Man selection was higher than that reported using antibiotic selection or with a visual marker. For papaya, the PMI/Man selection system for producing transgenic plants is a highly efficient addition to previously published methods for selection and may facilitate the stacking of multiple transgenes of interest. Additionally, since the PMI/Man selection system does not involve antibiotic or herbicide resistance genes, its use might reduce environmental concerns about the potential flow of those genes into related plant populations.

Determination of soil-to-plant transfer factors of {sup 137}Cs and {sup 90}Sr in the tropical environment of Bangladesh

Energy Technology Data Exchange (ETDEWEB)

Mollah, A.S.; Begum, A. [Atomic Energy Research Establishment (AERE), Savar, Dacca (Bangladesh); Ullah, S.M. [University of Dhaka (Bangladesh). Department of Soil Science

1998-07-01

Soil-to-plant transfer factors (TF) of {sup 137}Cs and {sup 90}Sr have been determined for different plants/crops, such as rice, beans, peanuts, pineapple, cabbage, tomato, spinach and grass. They were obtained from radioisotope experiments on plants grown in pots under outdoor ambient tropical conditions for three growing seasons (1994-1996). In the case of {sup 137}Cs and concerning the above mentioned plants/crops, the average TFs were found to be 0.28, 0.25, 0.77, 0.19, 0.23, 0.28, 0.59 and 0.18, respectively. In the case of {sup 90}Sr, the average TFs were found to be 0.82, 0.51, 0.20, 0.82, 0.69, 0.59, 0.91 and 0.84, respectively. A minor seasonal variation was observed. This study provides a database of TFs for tropical environments to be used, e.g., for radiological safety assessment models. (orig.) With 1 fig., 3 tabs., 12 refs.

Isotopes in tropical agriculture

Energy Technology Data Exchange (ETDEWEB)

NONE

1962-04-15

Ways in which the use of radioisotopes and radiation can help to improve the agriculture of tropical Africa were discussed by a panel of experts. The panel included scientists from Africa, Europe, and the United States, most of whom had had actual experience dealing with agricultural problems in various parts of tropical Africa. The experts agreed that radioisotopes and radiation might now be employed to particular advantage in tropical Africa to improve crop nutrition and combat insect pests. Other applications discussed were in the fields of hydrology, plant breeding and food preservation

Isotopes in tropical agriculture

International Nuclear Information System (INIS)

1962-01-01

Ways in which the use of radioisotopes and radiation can help to improve the agriculture of tropical Africa were discussed by a panel of experts. The panel included scientists from Africa, Europe, and the United States, most of whom had had actual experience dealing with agricultural problems in various parts of tropical Africa. The experts agreed that radioisotopes and radiation might now be employed to particular advantage in tropical Africa to improve crop nutrition and combat insect pests. Other applications discussed were in the fields of hydrology, plant breeding and food preservation

Chemical and physical analyses of selected plants and soils from Puerto Rico (1981-2000)

Science.gov (United States)

M.J. Sanchez; E. Lopez; A.E. Lugo

2015-01-01

This report contains the results of analyses conducted at the chemistry laboratory of the International Institute of Tropical Forestry in Puerto Rico from 1981 to 2000. The data set includes 109,177 plant analyses and 70,729 soil analyses. We report vegetation chemical data by plant part, species, life zone, soil order, geology, or parent material. Soil data are...

Plant Traits Demonstrate That Temperate and Tropical Giant Eucalypt Forests Are Ecologically Convergent with Rainforest Not Savanna

Science.gov (United States)

Tng, David Y. P.; Jordan, Greg J.; Bowman, David M. J. S.

2013-01-01

Ecological theory differentiates rainforest and open vegetation in many regions as functionally divergent alternative stable states with transitional (ecotonal) vegetation between the two forming transient unstable states. This transitional vegetation is of considerable significance, not only as a test case for theories of vegetation dynamics, but also because this type of vegetation is of major economic importance, and is home to a suite of species of conservation significance, including the world’s tallest flowering plants. We therefore created predictions of patterns in plant functional traits that would test the alternative stable states model of these systems. We measured functional traits of 128 trees and shrubs across tropical and temperate rainforest – open vegetation transitions in Australia, with giant eucalypt forests situated between these vegetation types. We analysed a set of functional traits: leaf carbon isotopes, leaf area, leaf mass per area, leaf slenderness, wood density, maximum height and bark thickness, using univariate and multivariate methods. For most traits, giant eucalypt forest was similar to rainforest, while rainforest, particularly tropical rainforest, was significantly different from the open vegetation. In multivariate analyses, tropical and temperate rainforest diverged functionally, and both segregated from open vegetation. Furthermore, the giant eucalypt forests overlapped in function with their respective rainforests. The two types of giant eucalypt forests also exhibited greater overall functional similarity to each other than to any of the open vegetation types. We conclude that tropical and temperate giant eucalypt forests are ecologically and functionally convergent. The lack of clear functional differentiation from rainforest suggests that giant eucalypt forests are unstable states within the basin of attraction of rainforest. Our results have important implications for giant eucalypt forest management. PMID:24358359

Extreme meteorological events in nuclear power plant siting, excluding tropical cyclones

International Nuclear Information System (INIS)

1981-01-01

This Safety Guide deals with the extremes of meteorological variables and the extreme meteorological phenomena in accordance with the general criteria of the Code. The Guide outlines a procedure based on the following steps: (1) The meteorological phenomena and variables are described and classified, according to their effects on safety. (2) Data sources are identified, and data are collected. (3) Meteorological variables such as air temperature are analysed to determine their design bases; and the design basis event in case of phenomena such as the design basis tornado is identified. (4) As appropriate, the design basis value for the variable, or the design basis for the phenomena (such as pressure drop and maximum wind speed of the design basis tornado), is defined. In the following sections, the general procedure for evaluating the design bases of extreme meteorological variables and phenomena is outlined. The procedure is then presented in detail for each variable or phenomenon considered. The variables characterizing the meteorological environment dealt with in this Guide are wind speed, atmospheric precipitation, and temperature. The extreme meteorological phenomena discussed here are the tornado and, briefly, the tropical cyclone, which is discussed more extensively in the Safety Guide on Design Basis Tropical Cyclone for Nuclear Power Plants (IAEA Safety Series No. 50-SG-S11B)

Tropical Fruit Irradiation-From Research to Commercial Application

International Nuclear Information System (INIS)

Moy, James H.

2005-09-01

Food irradiation is an emerging technology for the 21st century. Extensive research and development worldwide in the past 40 years have proved the versatility and efficacy. With low, medium to high dose, and using either a gamma, electrons, or x-ray source, radiation can: 1) disinfest plant products and spices; 2) extend shelf life of tubers, bulbs, and selected tropical fruits; 3) decontaminate meats and seafood; 4) sterilize spices and special meals; and 5) improve product utilization. Criteria for testing its efficacy include effectiveness, efficiency, and the ability to retain product quality. The use of irradiation as a quarantine treatment of tropical fruits is potentially attractive to countries growing these fruits. A two-prong research plan should aim at proving radiation's effectiveness in preventing emergence of all insect pests that might be on a fruit, and determining that all quality attributes of a host fruit are retained after irradiation, subsequent storage and shipment. ommercial application involves conducting an economical feasibility study; market research and testing; selection of radiation source and irradiator type; training of personnel for plant operations, radiation safety and dosimetry monitoring; designing of packages and choosing the most cost-effective means of transporting treated fruits to market destinations. When all of hese are achieved, it should lead to a continuous and profitable operation. Researchers at the University of Hawaii using a gamma irradiator from the mid-1960s to early 2000s had amassed a volume of data to prove the efficacy of radiation disinfestations. And installation of a commercial x-ray irradiator in 2000 on the Island of Hawaii has enabled fruit farmers and packers to use this technology for exporting tropical fruits to distant markets

Reasons for an outstanding plant diversity in the tropical Andes of Southern Ecuador

Directory of Open Access Journals (Sweden)

Michael Richter

2009-06-01

Full Text Available Long-term field studies in the scope of a multidisciplinary project in southern Ecuador revealed extraordinary high species numbers of many organismic groups. This article discusses reasons for the outstanding vascular plant diversity using a hierarchical scale-oriented top-down approach (Grüninger 2005, from the global scale to the local microscale. The global scale explains general (paleo- ecological factors valid for most parts of the humid tropics, addressing various hypotheses and theories, such as the “greater effective evolutionary time”, constant input of “accidentals”, the “seasonal variability hypothesis”, the “intermediate disturbance hypothesis”, and the impact of soil fertility. The macroscale focuses on the Andes in northwestern South America. The tropical Andes are characterised by many taxa of restricted range which is particularly true for the Amotape-Huancabamba region, i.e. the so called Andean Depression, which is effective as discrete phytogeographic transition as well as barrier zone. Interdigitation of northern and southern flora elements, habitat fragmentation, geological and landscape history, and a high speciation rate due to rapid genetic radiation of some taxa contribute to a high degree of diversification. The mesoscale deals with the special environmental features of the eastern mountain range, the Cordillera Real and surrounding areas in southern Ecuador. Various climatic characteristics, the orographic heterogeneity, the geologic and edaphic conditions as well as human impact are the most prominent factors augmenting plant species diversity. On microscale, prevailing regimes of disturbance and environmental stresses, the orographic basement, as well as the general role on the various mountain chains are considered. Here, micro-habitats e.g. niches for epiphytes, effects of micro-relief patterns, and successions after small-sized disturbance events are screened. Direct effects of human impact are

Soil-to-plant transfer of radiocaesium for selected tropical plant species in Bangladesh

International Nuclear Information System (INIS)

Rahman, M.M.; Rahman, M.M.; Koddus, A.; Ahmad, G.U.; Voigt, G.

2005-01-01

Soil-to-plant transfer factors (TF) of radiocaesium ( 137 Cs) were determined under field condition for grassy vegetation grown in Bangladesh at contaminated land in the Atomic Energy Research Establishment (AERE) campus. TF values for rice, grass and grassy/root vegetations grown in the same type of soil were also measured under pot condition. TF values of 137 Cs for grassy vegetation (2.4 x 10 -2 -4.2 x 10 -2 with an average of 3.1 x 10 -2 ± 0.005) obtained under field condition were slightly lower than the values for grass and grassy/root vegetations (2.9 x 10 -2 -6.6 x 10 -2 with an average of 4.8 x 10 -2 ± 0.01 for grass and grassy vegetations and 2.3 x 10 -2 -5.6 x 10 -2 with an average of 4.0 x 10 -2 ± 0.009 for root vegetations, respectively) obtained under pot condition. However, TF values (9.0 x 10 -3 -2.6 x 10 -2 with an average of 1.9 x 10 -2 ± 0.004) obtained for rice were about a factor of 4 lower than the values obtained for grass and grassy/root vegetations. When the properties of the AERE soils as input parameters were used in the soil-plant transfer model of Absalom, the estimated TF values (4.5 x 10 -2 -6.7 x 10 -2 with an average of 5.3 x 10 -2 ± 0.006) were consistent with the measured values obtained for grass and grassy vegetations under pot condition, however, the model overestimates the TF values for rice

Plant breeding and genetics newsletter. No. 3

International Nuclear Information System (INIS)

1999-06-01

This third issue of the Plant Breeding and Genetics Newsletter highlights forthcoming events including regional (Afra) training course on 'molecular characterization of genetic biodiversity in traditional and neglected crops selected for improvement through mutation techniques' and seminar on 'mutation techniques and biotechnology for tropical and subtropical plant improvement in Asia and Pacific regions'. Status of existing co-ordinated and technical co-operation research projects is also summarized

Does the edge effect influence plant community structure in a tropical dry forest?

Directory of Open Access Journals (Sweden)

Diogo Gallo Oliveira

2013-04-01

Full Text Available Edge effects are considered a key factor in regulating the structure of plant communities in different ecosystems. However, regardless to few studies, edge influence does not seem to be decisive in semiarid regions such as the Brazilian tropical dry forest known as Caatinga but this issue remains inconclusive. The present study tests the null hypothesis that the plant community of shrubs and trees does not change in its structure due to edge effects. Twenty-four plots (20 x 20 m were set up in a fragment of Caatinga, in which 12 plots were in the forest edges and 12 plots were inside the fragment. Tree richness, abundance and species composition did not differ between edge and interior plots. The results of this study are in agreement with the pattern previously found for semiarid environments and contrasts with previous results obtained in different environments such as Rainforests, Savanna and Forest of Araucaria, which indicate abrupt differences between the border and interior of the plant communities in these ecosystems, and suggest that the community of woody plants of the Caatinga is not ecologically affected by the presence of edges.

Ethnomedicinal and ecological status of plants in Garhwal Himalaya, India

Science.gov (United States)

2011-01-01

Background The northern part of India harbours a great diversity of medicinal plants due to its distinct geography and ecological marginal conditions. The traditional medical systems of northern India are part of a time tested culture and honored still by people today. These traditional systems have been curing complex disease for more than 3,000 years. With rapidly growing demand for these medicinal plants, most of the plant populations have been depleted, indicating a lack of ecological knowledge among communities using the plants. Thus, an attempt was made in this study to focus on the ecological status of ethnomedicinal plants, to determine their availability in the growing sites, and to inform the communities about the sustainable exploitation of medicinal plants in the wild. Methods The ecological information regarding ethnomedicinal plants was collected in three different climatic regions (tropical, sub-tropical and temperate) for species composition in different forest layers. The ecological information was assessed using the quadrate sampling method. A total of 25 quadrats, 10 × 10 m were laid out at random in order to sample trees and shrubs, and 40 quadrats of 1 × 1 m for herbaceous plants. In each climatic region, three vegetation sites were selected for ecological information; the mean values of density, basal cover, and the importance value index from all sites of each region were used to interpret the final data. Ethnomedicinal uses were collected from informants of adjacent villages. About 10% of inhabitants (older, experienced men and women) were interviewed about their use of medicinal plants. A consensus analysis of medicinal plant use between the different populations was conducted. Results Across the different climatic regions a total of 57 species of plants were reported: 14 tree species, 10 shrub species, and 33 herb species. In the tropical and sub-tropical regions, Acacia catechu was the dominant tree while Ougeinia oojeinensis in the

Ethnomedicinal and ecological status of plants in Garhwal Himalaya, India

Directory of Open Access Journals (Sweden)

Sheikh Mehraj A

2011-10-01

Full Text Available Abstract Background The northern part of India harbours a great diversity of medicinal plants due to its distinct geography and ecological marginal conditions. The traditional medical systems of northern India are part of a time tested culture and honored still by people today. These traditional systems have been curing complex disease for more than 3,000 years. With rapidly growing demand for these medicinal plants, most of the plant populations have been depleted, indicating a lack of ecological knowledge among communities using the plants. Thus, an attempt was made in this study to focus on the ecological status of ethnomedicinal plants, to determine their availability in the growing sites, and to inform the communities about the sustainable exploitation of medicinal plants in the wild. Methods The ecological information regarding ethnomedicinal plants was collected in three different climatic regions (tropical, sub-tropical and temperate for species composition in different forest layers. The ecological information was assessed using the quadrate sampling method. A total of 25 quadrats, 10 × 10 m were laid out at random in order to sample trees and shrubs, and 40 quadrats of 1 × 1 m for herbaceous plants. In each climatic region, three vegetation sites were selected for ecological information; the mean values of density, basal cover, and the importance value index from all sites of each region were used to interpret the final data. Ethnomedicinal uses were collected from informants of adjacent villages. About 10% of inhabitants (older, experienced men and women were interviewed about their use of medicinal plants. A consensus analysis of medicinal plant use between the different populations was conducted. Results Across the different climatic regions a total of 57 species of plants were reported: 14 tree species, 10 shrub species, and 33 herb species. In the tropical and sub-tropical regions, Acacia catechu was the dominant tree while

Extinction risk escalates in the tropics.

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Jana C Vamosi

Full Text Available The latitudinal biodiversity gradient remains one of the most widely recognized yet puzzling patterns in nature. Presently, the high level of extinction of tropical species, referred to as the "tropical biodiversity crisis", has the potential to erode this pattern. While the connection between species richness, extinction, and speciation has long intrigued biologists, these interactions have experienced increased poignancy due to their relevancy to where we should concentrate our conservation efforts. Natural extinction is a phenomenon thought to have its own latitudinal gradient, with lower extinction rates in the tropics being reported in beetles, birds, mammals, and bivalves. Processes that have buffered ecosystems from high extinction rates in the past may also buffer ecosystems against disturbance of anthropogenic origin. While potential parallels between historical and present-day extinction patterns have been acknowledged, they remain only superficially explored and plant extinction patterns have been particularly neglected. Studies on the disappearances of animal species have reached conflicting conclusions, with the rate of extinction appearing either higher or lower in species richness hotspots. Our global study of extinction risk in vascular plants finds disproportionately higher extinction risk in tropical countries, even when indicators of human pressure (GDP, population density, forest cover change are taken into account. Our results are at odds with the notion that the tropics represent a museum of plant biodiversity (places of historically lowered extinction and we discuss mechanisms that may reconcile this apparent contradiction.

Extinction risk escalates in the tropics.

Science.gov (United States)

Vamosi, Jana C; Vamosi, Steven M

2008-01-01

The latitudinal biodiversity gradient remains one of the most widely recognized yet puzzling patterns in nature. Presently, the high level of extinction of tropical species, referred to as the "tropical biodiversity crisis", has the potential to erode this pattern. While the connection between species richness, extinction, and speciation has long intrigued biologists, these interactions have experienced increased poignancy due to their relevancy to where we should concentrate our conservation efforts. Natural extinction is a phenomenon thought to have its own latitudinal gradient, with lower extinction rates in the tropics being reported in beetles, birds, mammals, and bivalves. Processes that have buffered ecosystems from high extinction rates in the past may also buffer ecosystems against disturbance of anthropogenic origin. While potential parallels between historical and present-day extinction patterns have been acknowledged, they remain only superficially explored and plant extinction patterns have been particularly neglected. Studies on the disappearances of animal species have reached conflicting conclusions, with the rate of extinction appearing either higher or lower in species richness hotspots. Our global study of extinction risk in vascular plants finds disproportionately higher extinction risk in tropical countries, even when indicators of human pressure (GDP, population density, forest cover change) are taken into account. Our results are at odds with the notion that the tropics represent a museum of plant biodiversity (places of historically lowered extinction) and we discuss mechanisms that may reconcile this apparent contradiction.

Tropical forest harvesting and taxation: a dynamic model of harvesting behavior under selective extraction systems

Science.gov (United States)

Robert F. Conrad; Malcolm Gillis; D. Evan Mercer

2005-01-01

A dynamic model of selective harvesting in multi-species,multi-age tropical forests is developed. Forests are predicted to exhibit different optimal harvesting profiles depending on the nature of their joint cost functions and own or cross-species stock effects. The model is applied to the controversy about incentives produced by various taxes. The impacts of specific...

Linking plant hydraulics and beta diversity in tropical forests

Energy Technology Data Exchange (ETDEWEB)

Christoffersen, Bradley [Earth and Environmental Sciences, Los Alamos National Laboratory, Los Alamos NM 87545 USA; Meir, Patrick [School of GeoSciences, University of Edinburgh, Edinburgh EH9 3FE UK; Research School of Biology, Australian National University, Canberra ACT 2601 Australia; McDowell, Nate G. [Pacific Northwest National Laboratory, Richland WA 99352 USA

2017-05-31

In tropical forests, studies of xylem traits governing water transport through plants, or ‘hydraulic architecture’ (Tyree et al., 1991), and changes in species composition across environmental gradients, or ‘beta diversity’ (Gentry, 1988; Ackerly & Cornwell, 2007), have progressedmostly in parallel until recently (Hao et al., 2008; Bartlett et al., 2016). In this issue of New Phytologist, Cosme et al. (pp. 000–5 000) present a timely contribution to the intersection of plant hydraulic architecture (HA) with trait-based community ecology. Building on previous biogeographical work that demonstrated shifts in species composition (beta diversity) across a gradient from valleys to plateaus in central Amazonia (Schietti et al., 2014), Cosme et al. explore how variation in HA might underpin this sorting, sampling pairs of congeneric species restrictedmostly to either plateau or valley habitats. Valley species had significantly lower wood density and higher hydraulically-weighted vessel diameter and vessel area. By contrast, trees with some of the largest hydraulically-weighted vessel diameters existed in tall, deciduous plateau species, while the leaf: sapwood area ratio decreased with height in valley but not plateau species. These intriguing results suggest that species differentiation in water transport traits mediate edaphic filtering along the valley-toplateau gradient, in contrast to previous work where wood mechanical support mediated valley-to-plateau environmental filtering (Fortunel et al., 2014).

Rubisco activity and gene expression of tropical tree species under ...

African Journals Online (AJOL)

Tropical rain forests contain an ecologically and physiologically diverse range of vegetation and habitats. Sun-acclimated plants can be divided into two groups, shade-tolerant and shade-intolerant, according to the plant's physiological and genetic responses. Some tropical species have potential capacity for light damage ...

Strategies for Improving Enterprise Standardization Management of Tropical Crop Machinery

Institute of Scientific and Technical Information of China (English)

无

2007-01-01

@@ There are two categories of tropical crop machinery. One comprises operation machinery that is used for planting, managing and harvesting tropical crops, while the other comprises process machinery for processing tropical crops. Tropical crop machinery is distinguished from other agricultural machinery by the special crops that such machinery cultivates and processes.

Effects of soil water depletion on the water relations in tropical kudzu

Directory of Open Access Journals (Sweden)

Adaucto Bellarmino de Pereira-Netto

1999-07-01

Full Text Available Tropical kudzu (Pueraria phaseoloides (Roxb. Benth., Leguminosae: Faboideae is native to the humid Southeastern Asia. Tropical kudzu has potential as a cover crop in regions subjected to dryness. The objective of this paper was to evaluate the effect of soil water depletion on leaflet relative water content (RWC, stomatal conductance (g and temperature (T L in tropical kudzu. RWC of waterstressed plants dropped from 96 to 78%, following a reduction in SWC from 0.25 to 0.17 g (H2O.g (dry soil-1.Stomatal conductance of stressed plants decreased from 221 to 98 mmol.m-2.s-1, following the reduction in soil water content (SWC. The day after re-irrigation, g of water stressed plants was 15% lower than g of unstressed plants. Differences in T L between waterstressed and unstressed plants (deltaT L rose linearly from 0.1 to 2.2ºC following progressive water deficit. RWC and T L of waterstressed plants paralled RWC and T L of unstressed plants the day after reirrigation. The strong decrease in SWC found in this study only induced moderate water stress in tropical kudzu. In addition, tropical kudzu recover rapidly from the induced water stress after the re-irrigation.

Predicting tropical plant physiology from leaf and canopy spectroscopy.

Science.gov (United States)

Doughty, Christopher E; Asner, Gregory P; Martin, Roberta E

2011-02-01

A broad regional understanding of tropical forest leaf photosynthesis has long been a goal for tropical forest ecologists, but it has remained elusive due to difficult canopy access and high species diversity. Here we develop an empirical model to predict sunlit, light-saturated, tropical leaf photosynthesis using leaf and simulated canopy spectra. To develop this model, we used partial least squares (PLS) analysis on three tropical forest datasets (159 species), two in Hawaii and one at the biosphere 2 laboratory (B2L). For each species, we measured light-saturated photosynthesis (A), light and CO(2) saturated photosynthesis (A(max)), respiration (R), leaf transmittance and reflectance spectra (400-2,500 nm), leaf nitrogen, chlorophyll a and b, carotenoids, and leaf mass per area (LMA). The model best predicted A [r(2) = 0.74, root mean square error (RMSE) = 2.9 μmol m(-2) s(-1))] followed by R (r(2) = 0.48), and A(max) (r(2) = 0.47). We combined leaf reflectance and transmittance with a canopy radiative transfer model to simulate top-of-canopy reflectance and found that canopy spectra are a better predictor of A (RMSE = 2.5 ± 0.07 μmol m(-2) s(-1)) than are leaf spectra. The results indicate the potential for this technique to be used with high-fidelity imaging spectrometers to remotely sense tropical forest canopy photosynthesis.

Seasonal dynamics in photosynthesis of woody plants at the northern limit of Asian tropics: potential role of fog in maintaining tropical rainforests and agriculture in Southwest China.

Science.gov (United States)

Zhang, Yong-Jiang; Holbrook, N Michele; Cao, Kun-Fang

2014-10-01

The lowland tropical rainforests in Xishuangbanna, Southwest (SW) China, mark the northern limit of Asian tropics. Fog has been hypothesized to play a role in maintaining rainforests and tropical crop production in this region, but the physiological mechanism has not been studied. The goals of this study were to characterize the seasonal dynamics in photosynthesis and to assess the potential for fog to mitigate chilling-induced photodamage for tropical trees and crops in Xishuangbanna. We measured seasonal dynamics in light-saturated net photosynthetic rate (Aa), stomatal conductance (gs), intercellular CO2 concentration, quantum yield of Photosystem II (Fv/Fm) and maximum P700 changes (Pm; indicates the amount of active PSI complex), as well as chilling resistance and fog (light/shading) effects on low temperature-induced decline in Fv/Fm and Pm for native tree and introduced lower latitude tree or woody shrub species grown in a tropical botanical garden. Despite significant decreases in Aa, gs, Pm and Fv/Fm, most species maintained considerably high Aa during the cool season (2.51-14.6 μmol m(-2) s(-1)). Shaded leaves exposed to seasonal low temperatures had higher Fv/Fm than sun-exposed leaves in the cool season. All species could tolerate 1.4 °C in the dark, whereas a combined treatment of low temperature and high light caused a distinctly faster decline in Pm and Fv/Fm compared with low temperature treatment alone. Because fog persistence avoids or shortens the duration of high light condition in the morning when the temperatures are still low, our results provide support for the hypothesis that fog reduces chilling damage to tropical plants in this region and thus plays a role in maintaining tropical rainforests and agriculture in SW China. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

[Regenerative morphological traits in a woody species community in Tumbesian tropical dry forest].

Science.gov (United States)

Romero-Saritama, José Miguel; Pérez-Rúuz, César

2016-06-01

The study of functional morphological traits enables us to know fundamental aspects of the dynamics of plant communities in local and global habitats. Regenerative morphological traits play an important role in defining plant history and ecological behavior. Seed and fruit characteristics determine to a large extent the patterns for dispersal, germination, establishment and seedling recruitment a given species exhibits on its natural habitat. Despite their prominent role, seed and fruit traits have been poorly studied at the community level of woody plant species in neo-tropical dry forests. In the present study we aimed at i) evaluate the functional role of morphological traits of seeds, fruits and embryo in woody plant species; ii) determine which are the morphological patterns present in seeds collected from the community of woody species that occur in neo-tropical dry forests; and iii) compare woody plant species seed mass values comparatively between neo-tropical dry and tropical forests. To do so, mature seeds were collected from 79 plant species that occur in the Tumbesian forest of Southwest Ecuador. The studied species included the 42 and 37 most representative tree and shrubbery species of the Tumbesian forest respectively. A total of 18 morphological traits (seven quantitative and 11 qualitative) were measured and evaluated in the seeds, fruits and embryos of the selected species, and we compared the seeds mass with other forest types. Our results showed a huge heterogeneity among traits values in the studied species. Seed mass, volume and number were the traits that vary the most at the community level, i.e. seed length ranged from 1.3 to 39 mm, and seed width from 0.6 to 25 mm. Only six embryo types were found among the 79 plant species. In 40 % of the cases, fully developed inverted embryos with large and thick cotyledons to store considerable amount of nutrients were recorded. We concluded that highly variable and functionally complementary

[Native plant resources to optimize the performances of forest rehabilitation in Mediterranean and tropical environment: some examples of nursing plant species that improve the soil mycorrhizal potential].

Science.gov (United States)

Duponnois, Robin; Ramanankierana, Heriniaina; Hafidi, Mohamed; Baohanta, Rondro; Baudoin, Ezékiel; Thioulouse, Jean; Sanguin, Hervé; Bâ, Amadou; Galiana, Antoine; Bally, René; Lebrun, Michel; Prin, Yves

2013-01-01

The overexploitation of natural resources, resulting in an increased need for arable lands by local populations, causes a serious dysfunction in the soil's biological functioning (mineral deficiency, salt stress, etc.). This dysfunction, worsened by the climatic conditions (drought), requires the implementation of ecological engineering strategies allowing the rehabilitation of degraded areas through the restoration of essential ecological services. The first symptoms of weathering processes of soil quality in tropical and Mediterranean environments result in an alteration of the plant cover structure with, in particular, the pauperization of plant species diversity and abundance. This degradation is accompanied by a weakening of soils and an increase of the impact of erosion on the surface layer resulting in reduced fertility of soils in terms of their physicochemical characteristics as well as their biological ones (e.g., soil microbes). Among the microbial components particularly sensitive to erosion, symbiotic microorganisms (rhizobia, Frankia, mycorrhizal fungi) are known to be key components in the main terrestrial biogeochemical cycles (C, N and P). Many studies have shown the importance of the management of these symbiotic microorganisms in rehabilitation and revegetation strategies of degraded environments, but also in improving the productivity of agrosystems. In particular, the selection of symbionts and their inoculation into the soil were strongly encouraged in recent decades. These inoculants were selected not only for their impact on the plant, but also for their ability to persist in the soil at the expense of the residual native microflora. The performance of this technique was thus evaluated on the plant cover, but its impact on soil microbial characteristics was totally ignored. The role of microbial diversity on productivity and stability (resistance, resilience, etc.) of eco- and agrosystems has been identified relatively recently and has led

Operator psychological selection system for nuclear power plant

International Nuclear Information System (INIS)

He Xuhong; Huang Xiangrui

2004-01-01

Based on a detailed job analysis of nuclear power plant operator including operation procedures analysis, interview with personnel familiar with operator job, and 9 events happened in the past in the plant involved operator error analysis, several operator work characteristics and performance influence factors are obtained. According to these specific characteristics and factors, referring to the psychological selection research results in the other related critical occupational fields, a full psychological selection system of nuclear power plant operator is forwarded in this paper, including 21 dimensions in 3 facets as general psychological ability, personality and psychological healthy. Practical measurement methods for the proposed selection dimensions are discussed in the end

The geology, botany and chemistry of selected peat-forming environments from temperate and tropical latitudes

Science.gov (United States)

Cameron, C.C.; Esterle, J.S.; Palmer, C.A.

1989-01-01

Peat has been studied in several geologic settings: (1) glaciated terrain in cold temperate Maine and Minnesota, U.S.A.; (2) an island in the Atlantic Ocean off the coast of Maine, where sea level is rising; (3) the warm temperate U.S. Atlantic and Gulf Coastal Plains, where sea level has changed often; and (4) the tropical coast of Sarawak, Malaysia, and the tropical delta of the Batang Hari River, Sumatra, Indonesia. Most of these deposits are domed (ombrotrophic or partly ombrotrophic) bogs in which peat accumulation continued above the surface of the surrounding soil. However, the bogs of the U.S. Atlantic and Gulf Coastal Plains are comparatively not as domed, and many have almost level surfaces. In some bogs, aquatic or semi-aquatic plant materials accumulated, replaced water in the depressions, and formed a surface on which marsh or swamp vegetation could subsequently live, die, and accumulate. In others, the plant materials accumulated initially on level silt or sand surfaces supporting marshes or swamps. As the peat dome formed, plants growing on it changed from luxuriant ones near the base of the dome, where nutrients were brought into the bog by surface and ground water, to stunted ones at the top of the dome, where the raised bogs are fed by nutrient-poor precipitation. The physical and chemical changes that take place in the sequence of environments from the pond stage of deposit development, through the grassy marsh stage, through the forested swamp stage, and finally through the heath dome stage can be measured in terms of acidity and ash, volatile matter, carbon, hydrogen, nitrogen, sulfur and oxygen contents, as well as in the kind and distribution of trace elements. The organic and inorganic contents of the deposits relate to geomorphology, and geomorphology relates to their settings. As models of coal formation, some domed peat deposits may help in solving problems of distribution and character of ancient coal beds. But clearly not all peat

Do Epigeal Termite Mounds Increase the Diversity of Plant Habitats in a Tropical Rain Forest in Peninsular Malaysia?

Science.gov (United States)

Beaudrot, Lydia; Du, Yanjun; Rahman Kassim, Abdul; Rejmánek, Marcel; Harrison, Rhett D.

2011-01-01

The extent to which environmental heterogeneity can account for tree species coexistence in diverse ecosystems, such as tropical rainforests, is hotly debated, although the importance of spatial variability in contributing to species co-existence is well recognized. Termites contribute to the micro-topographical and nutrient spatial heterogeneity of tropical forests. We therefore investigated whether epigeal termite mounds could contribute to the coexistence of plant species within a 50 ha plot at Pasoh Forest Reserve, Malaysia. Overall, stem density was significantly higher on mounds than in their immediate surroundings, but tree species diversity was significantly lower. Canonical correspondence analysis showed that location on or off mounds significantly influenced species distribution when stems were characterized by basal area. Like studies of termite mounds in other ecosystems, our results suggest that epigeal termite mounds provide a specific microhabitat for the enhanced growth and survival of certain species in these species-rich tropical forests. However, the extent to which epigeal termite mounds facilitate species coexistence warrants further investigation. PMID:21625558

Proxies of Tropical Cyclone Isotope Spikes in Precipitation: Landfall Site Selection

Science.gov (United States)

Lawrence, J. R.; Maddocks, R.

2011-12-01

The human experience of climate change is not one of gradual changes in seasonal or yearly changes in temperature or rainfall. Despite that most paleoclimatic reconstructions attempt to provide just such information. Humans experience climate change on much shorter time scales. We remember hurricanes, weeks of drought or overwhelming rainy periods. Tropical cyclones produce very low isotope ratios in both rainfall and in atmospheric water vapor. Thus, climate proxies that potentially record these low isotope ratios offer the most concrete record of climate change to which humans can relate. The oxygen isotopic composition of tropical cyclone rainfall has the potential to be recorded in fresh water carbonate fossil material, cave deposits and corals. The hydrogen isotopic composition of tropical cyclone rainfall has the potential to be recorded in tree ring cellulose and organic matter in fresh water bodies. The Class of carbonate organisms known as Ostracoda form their carapaces very rapidly. Thus fresh water ephemeral ponds in the subtropics are ideal locations for isotopic studies because they commonly are totally dry when tropical cyclones make landfall. The other proxies suffer primarily from a dilution effect. The water from tropical cyclones is mixed with pre-existing water. In cave deposits tropical cyclone rains mix with soil and ground waters. In the near shore coral environment the rain mixes with seawater. For tree rings there are three sources of water: soil water, atmospheric water vapor that exchanges with leaf water and tropical cyclone rain. In lakes because of their large size rainfall runoff mixes with ground water and preexisting water in the lake. A region that shows considerable promise is Texas / Northeast Mexico. In a study of surface waters that developed from the passage of Tropical Storm Allison (2001) in SE Texas both the pond water and Ostracoda that bloomed recorded the low oxygen isotope signal of that storm (Lawrence et al, 2008). In

The Multiple Impacts of Tropical Forest Fragmentation on Arthropod Biodiversity and on their Patterns of Interactions with Host Plants.

Science.gov (United States)

Benítez-Malvido, Julieta; Dáttilo, Wesley; Martínez-Falcón, Ana Paola; Durán-Barrón, César; Valenzuela, Jorge; López, Sara; Lombera, Rafael

2016-01-01

Tropical rain forest fragmentation affects biotic interactions in distinct ways. Little is known, however, about how fragmentation affects animal trophic guilds and their patterns of interactions with host plants. In this study, we analyzed changes in biotic interactions in forest fragments by using a multitrophic approach. For this, we classified arthropods associated with Heliconia aurantiaca herbs into broad trophic guilds (omnivores, herbivores and predators) and assessed the topological structure of intrapopulation plant-arthropod networks in fragments and continuous forests. Habitat type influenced arthropod species abundance, diversity and composition with greater abundance in fragments but greater diversity in continuous forest. According to trophic guilds, coleopteran herbivores were more abundant in continuous forest and overall omnivores in fragments. Continuous forest showed a greater diversity of interactions than fragments. Only in fragments, however, did the arthropod community associated with H aurantiaca show a nested structure, suggesting novel and/or opportunistic host-arthropod associations. Plants, omnivores and predators contributed more to nestedness than herbivores. Therefore, Heliconia-arthropod network properties do not appear to be maintained in fragments mainly caused by the decrease of herbivores. Our study contributes to the understanding of the impact of fragmentation on the structure and dynamics of multitrophic arthropod communities associated with a particular plant species of the highly biodiverse tropical forests. Nevertheless, further replication of study sites is needed to strengthen the conclusion that forest fragmentation negatively affects arthropod assemblages.

Marker-assisted selection of maintainer lines within an onion tropical population Seleção assistida por marcadores de linha mantenedora dentro de uma população de cebola tropical

Directory of Open Access Journals (Sweden)

Carlos Antonio Fernandes Santos

2010-04-01

Full Text Available The traditional onion (Allium cepa hybrid production requires the development of maintainer and male sterile lines and also a pollinator line with good specific combination ability. We report the identification of maintainer and male-sterile onion lines within the Brazilian 'Baia Periforme' derived population, 'Alfa São Francisco', associating random field pairing of male-fertile plants with selected male-sterile plants and PCR-based marker system monitoring S, T and N-cytoplasms. Male-sterile plants produced flowers with light green anthers which were easily detected in the field. A frequency of 2.0% of male-sterile plants was estimated in the 'Alfa São Francisco' sampled population. Male-sterile plants produced the 5'cob-marker 180-bp and the orfA501-marker 473-bp fragments, suggesting the T-cytoplasm type, while the maintainer line produced only the 5'cob-marker 180-bp. These identified lines will be important to develop tropical onion hybrids well-adapted to Brazilian low latitudes and to future comparative studies with other onion cytoplasmic genic male sterility systems.A produção tradicional de híbrido de cebola (Allium cepa requer o desenvolvimento de linhas mantenedoras e linhas macho estéreis, bem como uma linha polinizadora de boa capacidade específica de combinação. Reporta-se a identificação de linhas de cebola mantenedora e macho-estéreis numa população 'Alfa São Francisco' derivada da brasileira 'Baia Periforme', associando pareamento ao acaso no campo de plantas férteis com plantas macho-estéreis e sistema de PCR para monitoramento dos citoplasmas S, T e N. Plantas macho-estéreis produziram flores com anteras verde-claras, que foram facilmente identificadas no campo. A freqüência de 2,0% de plantas macho-estéreis foi estimada dentro de uma amostra da população 'Alfa São Francisco'. Plantas macho-estéreis produziram o marcador 5´cob de 180-pb e o marcador orfA501 de 473-pb, sugerindo que o citoplasma �

Plant invasions in protected areas of tropical pacific islands, with special reference to Hawaii

Science.gov (United States)

Hughes, R. Flint; Meyer, Jean-Yves; Loope, Lloyd L.

2013-01-01

Isolated tropical islands are notoriously vulnerable to plant invasions. Serious management for protection of native biodiversity in Hawaii began in the 1970s, arguably at Hawaii Volcanoes National Park. Concerted alien plant management began there in the 1980s and has in a sense become a model for protected areas throughout Hawaii and Pacific Island countries and territories. We review the relative successes of their strategies and touch upon how their experience has been applied elsewhere. Protected areas in Hawaii are fortunate in having relatively good resources for addressing plant invasions, but many invasions remain intractable, and invasions from outside the boundaries continue from a highly globalised society with a penchant for horticultural novelty. There are likely few efforts in most Pacific Islands to combat alien plant invasions in protected areas, but such areas may often have fewer plant invasions as a result of their relative remoteness and/or socio-economic development status. The greatest current needs for protected areas in this region may be for establishment of yet more protected areas, for better resources to combat invasions in Pacific Island countries and territories, for more effective control methods including biological control programme to contain intractable species, and for meaningful efforts to address prevention and early detection of potential new invaders.

α-Glucosidase inhibitory activity of selected Malaysian plants

Directory of Open Access Journals (Sweden)

Dzatil Awanis Mohd Bukhari

2017-01-01

Full Text Available Diabetes is a common metabolic disease indicated by unusually high plasma glucose level that can lead to major complications such as diabetic neuropathy, retinopathy, and cardiovascular diseases. One of the effective therapeutic managements of the disease is to reduce postprandial hyperglycemia through inhibition of α-glucosidase, a carbohydrate-hydrolyzing enzyme to retard overall glucose absorption. In recent years, a plenty of research works have been conducted looking for novel and effective α-glucosidase inhibitors (AGIs from natural sources as alternatives for the synthetic AGI due to their unpleasant side effects. Plants and herbs are rich with secondary metabolites that have massive pharmaceutical potential. Besides, studies showed that phytochemicals such as flavonoids, alkaloids, terpenoids, anthocyanins, glycosides, and phenolic compounds possess significant inhibitory activity against α-glucosidase enzyme. Malaysia is a tropical country that is rich with medicinal herbs. In this review, we focus on eight Malaysian plants with the potential as AGI to develop a potential functional food or lead compounds against diabetes.

α-Glucosidase Inhibitory Activity of Selected Malaysian Plants.

Science.gov (United States)

Mohd Bukhari, Dzatil Awanis; Siddiqui, Mohammad Jamshed; Shamsudin, Siti Hadijah; Rahman, Md Mukhlesur; So'ad, Siti Zaiton Mat

2017-01-01

Diabetes is a common metabolic disease indicated by unusually high plasma glucose level that can lead to major complications such as diabetic neuropathy, retinopathy, and cardiovascular diseases. One of the effective therapeutic managements of the disease is to reduce postprandial hyperglycemia through inhibition of α-glucosidase, a carbohydrate-hydrolyzing enzyme to retard overall glucose absorption. In recent years, a plenty of research works have been conducted looking for novel and effective α-glucosidase inhibitors (AGIs) from natural sources as alternatives for the synthetic AGI due to their unpleasant side effects. Plants and herbs are rich with secondary metabolites that have massive pharmaceutical potential. Besides, studies showed that phytochemicals such as flavonoids, alkaloids, terpenoids, anthocyanins, glycosides, and phenolic compounds possess significant inhibitory activity against α-glucosidase enzyme. Malaysia is a tropical country that is rich with medicinal herbs. In this review, we focus on eight Malaysian plants with the potential as AGI to develop a potential functional food or lead compounds against diabetes.

Pilot-Plant for Energy Recovery from Tropical Waste Food Materials ...

African Journals Online (AJOL)

An experimental unit for obtaining gaseous methane from waste food materials is discussed and results are presented for experimental tests with animal wastes and tropical waste food materials. The tropical waste food considered include garri, boiled beans and plantains. As expected, the animal wastes produced higher ...

Nuclear Power Plant project site selection geotechnical considerations

International Nuclear Information System (INIS)

Katti, V.J.; Banerjee, D.C.

1997-01-01

During the selection of a site for Nuclear Power Plant (NPP) and Radioactive Waste Plant (RWP), geotechnical investigations play a significant role in deciding merits and demerits of the sites. Any accidents in these units can play havoc on mankind and may leave bitter imprints on generations to come. Hence proper care has to be taken at the early stage for selecting the sites. Site selection procedure is a complicated one, because it involves experts from various disciplines like geology, geophysics, civil, mechanical electrical engineering, health-physics and other fields

Does genomic selection have a future in plant breeding?

Science.gov (United States)

Jonas, Elisabeth; de Koning, Dirk-Jan

2013-09-01

Plant breeding largely depends on phenotypic selection in plots and only for some, often disease-resistance-related traits, uses genetic markers. The more recently developed concept of genomic selection, using a black box approach with no need of prior knowledge about the effect or function of individual markers, has also been proposed as a great opportunity for plant breeding. Several empirical and theoretical studies have focused on the possibility to implement this as a novel molecular method across various species. Although we do not question the potential of genomic selection in general, in this Opinion, we emphasize that genomic selection approaches from dairy cattle breeding cannot be easily applied to complex plant breeding. Copyright © 2013 Elsevier Ltd. All rights reserved.

Characterizing the Suitability of Selected Indigenous Soil Improving Legumes in a Humid Tropical Environment Using Shoot and Root Attributes

Directory of Open Access Journals (Sweden)

Anikwe, MAN.

2003-01-01

Full Text Available We studied the biomass accumulation, root length, nodulation, and chemical composition of roots and shoot of ten indigenous soil improving legumes in a humid tropical ecosystem with the view to selecting species for soil improvement programmes. Two cultivars of Vigna unguiculata, and one each of Glycine max, Arachis hypogaea, Crotararia ochroleuca, Cajanus cajan, Pueraria phaseoloides, Lablab purpureus, Mucuna pruriens and Vigna subterranea as treatments were planted in 20 kg pots containing soil from an Oxic paleustalf in Nigeria. The pots were arranged in randomized complete block layout with three replications in a greenhouse at IITA Ibadan, Nigeria. Results from the work show that M. pruriens and C. cajan produced the highest quantity of biomass. Root elongation was highest in M. pruriens whereas A. hypogaea produced the most root nodules with native rhizobia. The highest quantity of nodule dry weight was produced by A. hypogaea and P. phaseoloides whereas most of the legumes except G. max and P. phaseoloides had high and statistically comparable N content of between 2.36 and 3.34 mg.kg-1 N. The results show that the legumes have different root and shoot characteristics, which should be taken into consideration when selecting species for soil improvement programmes.

The Multiple Impacts of Tropical Forest Fragmentation on Arthropod Biodiversity and on their Patterns of Interactions with Host Plants

Science.gov (United States)

Benítez-Malvido, Julieta; Dáttilo, Wesley; Martínez-Falcón, Ana Paola; Durán-Barrón, César; Valenzuela, Jorge; López, Sara; Lombera, Rafael

2016-01-01

Tropical rain forest fragmentation affects biotic interactions in distinct ways. Little is known, however, about how fragmentation affects animal trophic guilds and their patterns of interactions with host plants. In this study, we analyzed changes in biotic interactions in forest fragments by using a multitrophic approach. For this, we classified arthropods associated with Heliconia aurantiaca herbs into broad trophic guilds (omnivores, herbivores and predators) and assessed the topological structure of intrapopulation plant-arthropod networks in fragments and continuous forests. Habitat type influenced arthropod species abundance, diversity and composition with greater abundance in fragments but greater diversity in continuous forest. According to trophic guilds, coleopteran herbivores were more abundant in continuous forest and overall omnivores in fragments. Continuous forest showed a greater diversity of interactions than fragments. Only in fragments, however, did the arthropod community associated with H aurantiaca show a nested structure, suggesting novel and/or opportunistic host-arthropod associations. Plants, omnivores and predators contributed more to nestedness than herbivores. Therefore, Heliconia-arthropod network properties do not appear to be maintained in fragments mainly caused by the decrease of herbivores. Our study contributes to the understanding of the impact of fragmentation on the structure and dynamics of multitrophic arthropod communities associated with a particular plant species of the highly biodiverse tropical forests. Nevertheless, further replication of study sites is needed to strengthen the conclusion that forest fragmentation negatively affects arthropod assemblages. PMID:26731271

Pinus tropical com potencial para uso em plantios comerciais no Brasil. Tropical pine for commercial planting in Brazil.

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Marcos Silveira WREGE

2014-06-01

Full Text Available Entre os pinus tropicais, Pinus caribaea var. hondurensis é uma variedade natural, oriunda de região com clima tropical na América Central. A espécie se aclimatou bem em várias partes do mundo, em regiões com alta pluviosidade e temperaturas elevadas. Embora não tolere geadas severas, pode ser plantada em partes da região Sul do Brasil onde o clima é mais quente e a frequência de geadas é menor e é indicado para plantio em boa parte do Brasil, em mais de 3,5 milhões de km2 . Essa é uma variedade que apresenta alto rendimento em madeira de boa qualidade, além de possibilitar a exploração da resina. Neste trabalho, são apresentadas as regiões no Brasil que apresentam potencial para cultivo dessa variedade em regime de silvicultura intensiva, tomando como base sua região de origem no mundo. São indicadas para plantio comercial as zonas com os menores riscos de geada nos estados da região Sul, no Estado de São Paulo e nas demais regiões que oferecem condições climáticas favoráveis, principalmente de disponibilidade hídrica para o desenvolvimento dessa variedade de pinus. – Among tropical pines, Pinus caribaea var. hondurensis is a natural variation from the tropical regions of Central America. The species has adapted well in various parts of the world, in regions with high rainfall and high temperatures. Although intolerance to severe frosts, it can be grown in parts of southern Brazil, where the climate is hot, with infrequent frosts and even can be used for commercial planting in over 3.5 million square kilometers.This variety presents high yield in quality wood as well as resin. This work shows regions in Brazil where environmental conditions are favorable for commercial plantations with this variety, by making comparisons with the conditions in its origin. Climatic zones within the Southern Region, as well as in the state of São Paulo and elsewhere with the lowest risks of frost and plenty of water for the

Bird Pollinator Visitation is Equivalent in Island and Plantation Planting Designs in Tropical Forest Restoration Sites

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Ginger M. Thurston

2013-03-01

Full Text Available Active restoration is one strategy to reverse tropical forest loss. Given the dynamic nature of climates, human populations, and other ecosystem components, the past practice of using historical reference sites as restoration targets is unlikely to result in self-sustaining ecosystems. Restoring sustainable ecological processes like pollination is a more feasible goal. We investigated how flower cover, planting design, and landscape forest cover influenced bird pollinator visits to Inga edulis trees in young restoration sites in Costa Rica. I. edulis trees were located in island plantings, where seedlings had been planted in patches, or in plantation plantings, where seedlings were planted to cover the restoration area. Sites were located in landscapes with scant (10–21% or moderate (35–76% forest cover. Trees with greater flower cover received more visits from pollinating birds; neither planting design nor landscape forest cover influenced the number of pollinator visits. Resident hummingbirds and a migratory bird species were the most frequent bird pollinators. Pollination in the early years following planting may not be as affected by details of restoration design as other ecological processes like seed dispersal. Future work to assess the quality of various pollinator species will be important in assessing this idea.

[Historical research of cinchona cultivation in Japan (Part 2). Useful tropical plants introduced from Java and India in the early Meiji era].

Science.gov (United States)

Nagumo, Seiji; Sasaki, Yohei; Takido, Michio

2010-01-01

In the early Meiji era, Takeaki Enomoto made a proposal to the government that cinchona and coffee seedlings be introduced to Japan. In response, the Meiji government dispatched Masatsugu Takeda of the Ministry of Internal Affairs to Java and India from March to August 1878 for the purpose of investigating useful plants of tropical origin and introducing them to Japan. This paper clarifies the route to those destinations and the plants obtained locally. Using the seeds obtained from India during his travels, the cultivation of cinchona was attempted in 1882 for the first time in Japan. In Ogasawara, coffee cultivation was conducted, again for the first time in Japan, using coffee seeds brought back from Java. The cultivation of coffee was successful and served as the foundation of the Ogasawara coffee that exists to this day. Takeda also introduced a number of books and materials related to useful tropical plants available as a result of his travels, which contributed to the promotion of new industries and businesses in the Meiji era.

Factors of site selection for nuclear power plants in selected industrial states

International Nuclear Information System (INIS)

Hoffmann, L.; Obermair, G.; Ringler, W.; Romahn, B.; Sanders, H.

1978-01-01

The range of the tasks within the project consists of working out an optimal catalogue of criteria for the site selection for nuclear power plants; establishing a structured documentation system for the criteria and licensing procedures used by selected industrial countries when selecting sites for nuclear power plants; analyzing and evaluating the documented material with the aim of supplying the basis for decisions concerning land use. The tasks are being realized within a technological ring of data (for the period until 1990, reactor types, cooling, power-heat coupling, special sites, block sizes, local concentration) and a set politico-economical ring of data for the following countries: F.R. Germany, Belgium, Switzerland, Great Britain, Sweden, Denmark, Austria, France, Netherlands, USA, Japan, Yougoslavia. (HP) [de

Radiocesium contamination behavior and its effect on potassium absorption in tropical or subtropical plants

Energy Technology Data Exchange (ETDEWEB)

Carvalho, C. [Instituto de Fisica, Universidade Federal Fluminense, Av. Litoranea s/n, Gragoata, Niteroi, Rio de Janeiro, Cep 24210-340 (Brazil); Anjos, R.M. [Instituto de Fisica, Universidade Federal Fluminense, Av. Litoranea s/n, Gragoata, Niteroi, Rio de Janeiro, Cep 24210-340 (Brazil)]. E-mail: meigikos@if.uff.br; Mosquera, B. [Instituto de Fisica, Universidade Federal Fluminense, Av. Litoranea s/n, Gragoata, Niteroi, Rio de Janeiro, Cep 24210-340 (Brazil); Macario, K. [Instituto de Fisica, Universidade Federal Fluminense, Av. Litoranea s/n, Gragoata, Niteroi, Rio de Janeiro, Cep 24210-340 (Brazil); Veiga, R. [Instituto de Fisica, Universidade Federal Fluminense, Av. Litoranea s/n, Gragoata, Niteroi, Rio de Janeiro, Cep 24210-340 (Brazil)

2006-07-01

The accumulation and long-term decline of radiocesium contamination in tropical plant species was studied through measurements of gamma-ray spectra from pomegranate (Punica granatum) and chili pepper (Capsicum fructescens) trees. The plants were originally grown at a {sup 137}Cs contaminated site (where a radiological accident occurred in the city of Goiania, Brazil, in 1987), and transplanted to uncontaminated soil, so that the main source of contamination of the new leaves and fruits would be the fraction of the available radiocesium in the body of the plants. Measurements of {sup 137}Cs and {sup 4}K concentrations along the roots, main trunk, twigs, leaves and fruits before and after the transplant process of both plant species indicated a direct competition between Cs and K ions, suggesting that these elements could have a common accumulation mechanism. Cesium transfer factors from soil to pomegranate, green and red chili pepper fruits were evaluated as 0.4 {+-} 0.1, 0.06 {+-} 0.01 and 0.05 {+-} 0.01, respectively. Biological half-life values due to {sup 137}Cs translocation from the tree reservoir (BHL{sub T}) were calculated as 0.30 years for pomegranate, 0.12 years and 0.07 years for red and green peppers, respectively.

Radiocesium contamination behavior and its effect on potassium absorption in tropical or subtropical plants

International Nuclear Information System (INIS)

Carvalho, C.; Anjos, R.M.; Mosquera, B.; Macario, K.; Veiga, R.

2006-01-01

The accumulation and long-term decline of radiocesium contamination in tropical plant species was studied through measurements of gamma-ray spectra from pomegranate (Punica granatum) and chili pepper (Capsicum fructescens) trees. The plants were originally grown at a 137 Cs contaminated site (where a radiological accident occurred in the city of Goiania, Brazil, in 1987), and transplanted to uncontaminated soil, so that the main source of contamination of the new leaves and fruits would be the fraction of the available radiocesium in the body of the plants. Measurements of 137 Cs and 4 K concentrations along the roots, main trunk, twigs, leaves and fruits before and after the transplant process of both plant species indicated a direct competition between Cs and K ions, suggesting that these elements could have a common accumulation mechanism. Cesium transfer factors from soil to pomegranate, green and red chili pepper fruits were evaluated as 0.4 ± 0.1, 0.06 ± 0.01 and 0.05 ± 0.01, respectively. Biological half-life values due to 137 Cs translocation from the tree reservoir (BHL T ) were calculated as 0.30 years for pomegranate, 0.12 years and 0.07 years for red and green peppers, respectively

Ectomycorrhizal fungi in Amazonian tropical forests in Colombia

NARCIS (Netherlands)

Vasco Palacios, A.M.

2016-01-01

The ectomycorrhizal (EcM) symbiosis was assumed to be restricted to the temperate regions where forests are dominated by EcM host plants, and the tropics were supposed to be dominated by endomycorrhizal fungi. However, evidence of the presence of EcM symbiosis in tropical lowland ecosystems has been

Soil-water distribution coefficients and plant transfer factors for {sup 134}Cs, {sup 85}Sr and {sup 65}Zn under field conditions in tropical Australia

Energy Technology Data Exchange (ETDEWEB)

Twining, J.R. E-mail: jrt@ansto.gov.au; Payne, T.E.; Itakura, T

2004-07-01

Measurements of soil-to-plant transfer of {sup 134}Cs, {sup 85}Sr and {sup 65}Zn from two tropical red earth soils ('Blain' and 'Tippera') to sorghum and mung crops have been undertaken in the north of Australia. The aim of the study was to identify factors that control bioaccumulation of these radionuclides in tropical regions, for which few previous data are available. Batch sorption experiments were conducted to determine the distribution coefficient (K{sub d}) of the selected radionuclides at pH values similar to natural pH values, which ranged from about 5.5 to 6.7. In addition, K{sub d} values were obtained at one pH unit above and below the soil-water equilibrium pH values to determine the effect of pH. The adsorption of Cs showed no pH dependence, but the K{sub d} values for the Tippera soils (2300-4100 ml/g) exceeded those for the Blain soils (800-1200 ml/g) at equilibrium pH. This was related to the greater clay content of the Tippera soil. Both Sr and Zn were more strongly adsorbed at higher pH values, but the K{sub d} values showed less dependence on the soil type. Strontium K{sub d}s were 30-60 ml/g whilst Zn ranged from 160 to 1630 ml/g for the two soils at equilibrium pH. With the possible exception of Sr, there was no evidence for downward movement of radionuclides through the soils during the course of the growing season. There was some evidence of surface movement of labelled soil particles. Soil-to-plant transfer factors varied slightly between the soils. The average results for sorghum were 0.1-0.3 g/g for Cs, 0.4-0.8 g/g for Sr and 18-26 g/g for Zn (dry weight) with the initial values relating to Blain and the following values to Tippera. Similar values were observed for the mung bean samples. The transfer factors for Cs and Sr were not substantially different from the typical values observed in temperate studies. However, Zn transfer factors for plants grown on both these tropical soils were greater than for soils in

Modelling tropical forests response to logging

Science.gov (United States)

Cazzolla Gatti, Roberto; Di Paola, Arianna; Valentini, Riccardo; Paparella, Francesco

2013-04-01

Tropical rainforests are among the most threatened ecosystems by large-scale fragmentation due to human activity such as heavy logging and agricultural clearance. Although, they provide crucial ecosystem goods and services, such as sequestering carbon from the atmosphere, protecting watersheds and conserving biodiversity. In several countries forest resource extraction has experienced a shift from clearcutting to selective logging to maintain a significant forest cover and understock of living biomass. However the knowledge on the short and long-term effects of removing selected species in tropical rainforest are scarce and need to be further investigated. One of the main effects of selective logging on forest dynamics seems to be the local disturbance which involve the invasion of open space by weed, vines and climbers at the expense of the late-successional state cenosis. We present a simple deterministic model that describes the dynamics of tropical rainforest subject to selective logging to understand how and why weeds displace native species. We argue that the selective removal of tallest tropical trees carries out gaps of light that allow weeds, vines and climbers to prevail on native species, inhibiting the possibility of recovery of the original vegetation. Our results show that different regime shifts may occur depending on the type of forest management adopted. This hypothesis is supported by a dataset of trees height and weed/vines cover that we collected from 9 plots located in Central and West Africa both in untouched and managed areas.

Effects of cold selective breeding on the body length, fatty acid content, and productivity of the tropical copepod Apocyclops royi (Cyclopoida, Copepoda)

DEFF Research Database (Denmark)

Pan, Yen-Ju; Souissi, Anissa; Sadovskaya, Irina

2017-01-01

In this study, we conducted a novel approach of selective breeding by using temperature acclimation to enhance the aquaculture potential of the tropical cyclopoid copepod Apocyclops royi. Two copepod culture strains were acclimated separately at high (28°C, control strain) and low (18°C, selective...

Effects of Mode of Target Task Selection on Learning about Plants in a Mobile Learning Environment: Effortful Manual Selection versus Effortless QR-Code Selection

Science.gov (United States)

Gao, Yuan; Liu, Tzu-Chien; Paas, Fred

2016-01-01

This study compared the effects of effortless selection of target plants using quick respond (QR) code technology to effortful manual search and selection of target plants on learning about plants in a mobile device supported learning environment. In addition, it was investigated whether the effectiveness of the 2 selection methods was…

Are we filling the data void? An assessment of the amount and extent of plant collection records and census data available for tropical South America.

Directory of Open Access Journals (Sweden)

Kenneth Feeley

Full Text Available Large-scale studies are needed to increase our understanding of how large-scale conservation threats, such as climate change and deforestation, are impacting diverse tropical ecosystems. These types of studies rely fundamentally on access to extensive and representative datasets (i.e., "big data". In this study, I asses the availability of plant species occurrence records through the Global Biodiversity Information Facility (GBIF and the distribution of networked vegetation census plots in tropical South America. I analyze how the amount of available data has changed through time and the consequent changes in taxonomic, spatial, habitat, and climatic representativeness. I show that there are large and growing amounts of data available for tropical South America. Specifically, there are almost 2,000,000 unique geo-referenced collection records representing more than 50,000 species of plants in tropical South America and over 1,500 census plots. However, there is still a gaping "data void" such that many species and many habitats remain so poorly represented in either of the databases as to be functionally invisible for most studies. It is important that we support efforts to increase the availability of data, and the representativeness of these data, so that we can better predict and mitigate the impacts of anthropogenic disturbances.

W Photoprotection in Tropical Marine Organisms

Science.gov (United States)

Armstrong, Roy A.

1997-01-01

Increasing levels of ultraviolet (UV) radiation reaching the earth's surface which results from stratospheric ozone depletions could have serious implications for terrestrial plants and for aquatic organisms within the euphotic zone. A documented 9% decline in ozone at mid-latitudes is considered to produce a 12% increase in harmful UV radiation. The biologically damaging effects of higher UV levels, particularly W-B (280-320 rim), could manifest earlier in the tropics because of the relative thinness of the earth's equatorial ozone layer. Tropical marine organisms are also living close to their upper tolerance levels of water temperature, However, despite the large potential effects on plants and animals, little is known about UV effects on tropical ecosystems. Long-term ecological studies are needed to quantify the effects of increased UV radiation on terrestrial and marine ecosystems and to produce reliable data for prediction. Plants have developed several mechanisms to protect themselves from harmful UV radiation, one of which is the production of secondary leaf pigments that absorb W-B radiation (screening pigments). A higher concentration of screening pigments (e.g. flavonoids) in leaves may be interpreted as a natural response to increased W radiation. If higher concentrations of flavonoids filter out the excessive W radiation, no damage will occur, as suggested by Caldwell et al. (1989) and Tevini (1993). Failure to screen all W-B may result in deleterious effects on photosynthesis, plant genetic material, and plant and leaf morphology and growth. Eventually this will have an impact on ecosystem processes, structure, species composition, and productivity. This paper describes an ongoing project that is assessing the responses of mangroves, seagrasses and corals to W radiation by studying pigment concentrations, biophysical parameters, and variations in spectral reflectance in the field and in W-reduction experiments. Preliminary results on the distribution

Evaluation of ash from some tropical plants of Nigeria for the control of Sclerotium rolfsii Sacc. on wheat (Triticum aestivum L.).

Science.gov (United States)

Enikuomehin, O A; Ikotun, T; Ekpo, E J

1998-01-01

Eleven ash samples, from organs of nine tropical plants, were screened for their abilities to inhibit mycelial growth and sclerotial germination of a Nigerian isolate of Sclerotium rolfsii on agar and in the soil. Ten ash samples showed some activity against mycelial growth of S. rolfsii in vitro. Ash samples from Delonix regia stem wood, Mangifera indica leaf and Vernonia amygdalina leaf were most effective as each totally inhibited mycelial growth of S. rolfsii in vitro. Ocimum gratissimum leaf ash, D. regia wood ash and Musa paradisiaca flower bract ash inhibited sclerotial germination on agar. Nine ash samples protected seeds against pre-emergence rot. Ash from M. indica leaf, V. amygdalina leaf and Azadirachta indica leaf protected seedlings against post-emergence infection. Eichornia crassipes ash, which was ineffective in vitro, offered some protection to seeds in soil against pre-emergence rot. The study demonstrates potentials of ash samples from tropical plants in control of S. rolfsii on wheat.

The biodiversity cost of carbon sequestration in tropical savanna.

Science.gov (United States)

Abreu, Rodolfo C R; Hoffmann, William A; Vasconcelos, Heraldo L; Pilon, Natashi A; Rossatto, Davi R; Durigan, Giselda

2017-08-01

Tropical savannas have been increasingly viewed as an opportunity for carbon sequestration through fire suppression and afforestation, but insufficient attention has been given to the consequences for biodiversity. To evaluate the biodiversity costs of increasing carbon sequestration, we quantified changes in ecosystem carbon stocks and the associated changes in communities of plants and ants resulting from fire suppression in savannas of the Brazilian Cerrado, a global biodiversity hotspot. Fire suppression resulted in increased carbon stocks of 1.2 Mg ha -1 year -1 since 1986 but was associated with acute species loss. In sites fully encroached by forest, plant species richness declined by 27%, and ant richness declined by 35%. Richness of savanna specialists, the species most at risk of local extinction due to forest encroachment, declined by 67% for plants and 86% for ants. This loss highlights the important role of fire in maintaining biodiversity in tropical savannas, a role that is not reflected in current policies of fire suppression throughout the Brazilian Cerrado. In tropical grasslands and savannas throughout the tropics, carbon mitigation programs that promote forest cover cannot be assumed to provide net benefits for conservation.

Tropical Agro-Sciences

International Nuclear Information System (INIS)

Anon.

1977-01-01

The Tropical Agro-Sciences Division has two functions: conduct research on the impact of air pollution on tropical agricultural and to provide training to UPR graduate students and visiting scientists. Since the reorientation of the Center's interests under ERDA, the Division has directed its research activities, with particular emphasis on the effects of atmospheric pollution on tropical agriculture in the Guayanilla-Penuelas region, which has a fossil-fuel power plant, petroleum refineries, and associated industries. This new area of research is important to ERDA because the knowledge gained regarding the effects of air pollution related to energy technology on the agricultural environment and productivity will be useful in planning future energy developments. Information about the potential harm of air pollutants to man through the food chain and about ways of alleviating their impact on agriculture are of practical importance. Studies of the mechanisms involved in pollution injury, protection, and tolerance are of basic significance

Plant delta 15N correlates with the transpiration efficiency of nitrogen acquisition in tropical trees.

Science.gov (United States)

Cernusak, Lucas A; Winter, Klaus; Turner, Benjamin L

2009-11-01

Based upon considerations of a theoretical model of (15)N/(14)N fractionation during steady-state nitrate uptake from soil, we hypothesized that, for plants grown in a common soil environment, whole-plant delta(15)N (deltaP) should vary as a function of the transpiration efficiency of nitrogen acquisition (F(N)/v) and the difference between deltaP and root delta(15)N (deltaP - deltaR). We tested these hypotheses with measurements of several tropical tree and liana species. Consistent with theoretical expectations, both F(N)/v and deltaP - deltaR were significant sources of variation in deltaP, and the relationship between deltaP and F(N)/v differed between non-N(2)-fixing and N(2)-fixing species. We interpret the correlation between deltaP and F(N)/v as resulting from variation in mineral nitrogen efflux-to-influx ratios across plasma membranes of root cells. These results provide a simple explanation of variation in delta(15)N of terrestrial plants and have implications for understanding nitrogen cycling in ecosystems.

Biological screening of Brazilian medicinal plants

Directory of Open Access Journals (Sweden)

Tânia Maria de Almeida Alves

2000-06-01

Full Text Available In this study, we screened sixty medicinal plant species from the Brazilian savanna ("cerrado" that could contain useful compounds for the control of tropical diseases. The plant selection was based on existing ethnobotanic information and interviews with local healers. Plant extracts were screened for: (a molluscicidal activity against Biomphalaria glabrata, (b toxicity to brine shrimp (Artemia salina L., (c antifungal activity in the bioautographic assay with Cladosporium sphaerospermum and (d antibacterial activity in the agar diffusion assay against Staphylococcus aureus, Escherichia coli, Bacillus cereus and Pseudomonas aeruginosa. Forty-two species afforded extracts that showed some degree of activity in one or more of these bioassays.

Impacts of Airborne Lidar Pulse Density on Estimating Biomass Stocks and Changes in a Selectively Logged Tropical Forest

Directory of Open Access Journals (Sweden)

Carlos Alberto Silva

2017-10-01

Full Text Available Airborne lidar is a technology well-suited for mapping many forest attributes, including aboveground biomass (AGB stocks and changes in selective logging in tropical forests. However, trade-offs still exist between lidar pulse density and accuracy of AGB estimates. We assessed the impacts of lidar pulse density on the estimation of AGB stocks and changes using airborne lidar and field plot data in a selectively logged tropical forest located near Paragominas, Pará, Brazil. Field-derived AGB was computed at 85 square 50 × 50 m plots in 2014. Lidar data were acquired in 2012 and 2014, and for each dataset the pulse density was subsampled from its original density of 13.8 and 37.5 pulses·m−2 to lower densities of 12, 10, 8, 6, 4, 2, 0.8, 0.6, 0.4 and 0.2 pulses·m−2. For each pulse density dataset, a power-law model was developed to estimate AGB stocks from lidar-derived mean height and corresponding changes between the years 2012 and 2014. We found that AGB change estimates at the plot level were only slightly affected by pulse density. However, at the landscape level we observed differences in estimated AGB change of >20 Mg·ha−1 when pulse density decreased from 12 to 0.2 pulses·m−2. The effects of pulse density were more pronounced in areas of steep slope, especially when the digital terrain models (DTMs used in the lidar derived forest height were created from reduced pulse density data. In particular, when the DTM from high pulse density in 2014 was used to derive the forest height from both years, the effects on forest height and the estimated AGB stock and changes did not exceed 20 Mg·ha−1. The results suggest that AGB change can be monitored in selective logging in tropical forests with reasonable accuracy and low cost with low pulse density lidar surveys if a baseline high-quality DTM is available from at least one lidar survey. We recommend the results of this study to be considered in developing projects and national

Neuroprotection and enhanced neurogenesis by extract from the tropical plant Knema laurina after inflammatory damage in living brain tissue.

Science.gov (United States)

Häke, Ines; Schönenberger, Silvia; Neumann, Jens; Franke, Katrin; Paulsen-Merker, Katrin; Reymann, Klaus; Ismail, Ghazally; Bin Din, Laily; Said, Ikram M; Latiff, A; Wessjohann, Ludger; Zipp, Frauke; Ullrich, Oliver

2009-01-03

Inflammatory reactions in the CNS, resulting from a loss of control and involving a network of non-neuronal and neuronal cells, are major contributors to the onset and progress of several major neurodegenerative diseases. Therapeutic strategies should therefore keep or restore the well-controlled and finely-tuned balance of immune reactions, and protect neurons from inflammatory damage. In our study, we selected plants of the Malaysian rain forest by an ethnobotanic survey, and investigated them in cell-based-assay-systems and in living brain tissue cultures in order to identify anti-inflammatory and neuroprotective effects. We found that alcoholic extracts from the tropical plant Knema laurina (Black wild nutmeg) exhibited highly anti-inflammatory and neuroprotective effects in cell culture experiments, reduced NO- and IL-6-release from activated microglia cells dose-dependently, and protected living brain tissue from microglia-mediated inflammatory damage at a concentration of 30 microg/ml. On the intracellular level, the extract inhibited ERK-1/2-phosphorylation, IkB-phosphorylation and subsequently NF-kB-translocation in microglia cells. K. laurina belongs to the family of Myristicaceae, which have been used for centuries for treatment of digestive and inflammatory diseases and is also a major food plant of the Giant Hornbill. Moreover, extract from K. laurina promotes also neurogenesis in living brain tissue after oxygen-glucose deprivation. In conclusion, extract from K. laurina not only controls and limits inflammatory reaction after primary neuronal damage, it promotes moreover neurogenesis if given hours until days after stroke-like injury.

The effects of the insecticide lambda-Cyhalothrin on the earthworm Eisenia fetida under experimental conditions of tropical and temperate regions.

Science.gov (United States)

Garcia, Marcos; Scheffczyk, Adam; Garcia, Terezinha; Römbke, Jörg

2011-02-01

Plant Protection Products can affect soil organisms and thus might have negative impacts on soil functions. Little research has been performed on their impact on tropical soils. Therefore, the effects of the insecticide lambda-Cyhalothrin on earthworms were evaluated in acute and chronic laboratory tests modified for tropical conditions, i.e. at selected temperatures (20 and 28°C) and with two strains (temperate and tropical) of the compost worm Eisenia fetida. The insecticide was spiked in two natural soils, in OECD artificial soil and a newly developed tropical artificial soil. The effects of lambda-Cyhalothrin did rarely vary in the same soil at tropical (LC50: 68.5-229 mg a.i./kg dry weight (DW); EC50: 54.2-60.2 mg a.i./kg DW) and temperate (LC50: 99.8-140 mg a.i./kg DW; EC50: 37.4-44.5 mg a.i./kg DW) temperatures. In tests with tropical soils and high temperature, effect values differed by up to a factor of ten. Copyright © 2010 Elsevier Ltd. All rights reserved.

Testing the stress-gradient hypothesis during the restoration of tropical degraded land using the shrub Rhodomyrtus tomentosa as a nurse plant

Science.gov (United States)

Nan Liu; Hai Ren; Sufen Yuan; Qinfeng Guo; Long Yang

2013-01-01

The relative importance of facilitation and competition between pairwise plants across abiotic stress gradients as predicted by the stress-gradient hypothesis has been confirmed in arid and temperate ecosystems, but the hypothesis has rarely been tested in tropical systems, particularly across nutrient gradients. The current research examines the interactions between a...

Induction and selection of mutants from in vitro cultured plant cells

Energy Technology Data Exchange (ETDEWEB)

Lee, Yung Il; Kim, Jae Sung; Shin, In Chul; Lee, Sang Jae [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

1994-07-01

Mutant cell lines are useful for biochemical, physiological and genetical material for marker in various genetic manipulation experiments and for the direct use in crop plant improvement. Mutant selection may lead to the production of plants showing resistance or tolerance to specific environmental stress, such as solinity, drought, toxed metals, herbicides, pathogens and low temperature. In this review, these included the production of the somatic variation, the selection process itself and stability of the selected characters in cell culture and regenerated plant. Which would seem to be useful for improving plants and securring genetic resources. 45 refs. (Author).

Induction and selection of mutants from in vitro cultured plant cells

International Nuclear Information System (INIS)

Lee, Yung Il; Kim, Jae Sung; Shin, In Chul; Lee, Sang Jae

1994-07-01

Mutant cell lines are useful for biochemical, physiological and genetical material for marker in various genetic manipulation experiments and for the direct use in crop plant improvement. Mutant selection may lead to the production of plants showing resistance or tolerance to specific environmental stress, such as solinity, drought, toxed metals, herbicides, pathogens and low temperature. In this review, these included the production of the somatic variation, the selection process itself and stability of the selected characters in cell culture and regenerated plant. Which would seem to be useful for improving plants and securring genetic resources. 45 refs. (Author)

Selection/licensing of nuclear power plant operators

International Nuclear Information System (INIS)

Saari, L.M.

1983-07-01

An important aspect of nuclear power plant (NPP) safety is the reactor operator in the control room. The operators are the first individuals to deal with an emergency situation, and thus, effective performance on their part is essential for safe plant operations. Important issues pertaining to NPP reactor operators would fall within the personnel subsystem of our safety system analysis. While there are many potential aspects of the personnel subsystem, a key first step in this focus is the selection of individuals - attempting to choose individuals for the job of reactor operator who will safely perform the job. This requires a valid (job-related) selection process. Some background information on the Nuclear Regulatory Commission (NRC) licensing process used for selecting NPP reactor operators is briefly presented and a description of a research endeavor now underway at Battelle for developing a valid reactor operator licensing examination is included

Microbiome Selection Could Spur Next-Generation Plant Breeding Strategies.

Science.gov (United States)

Gopal, Murali; Gupta, Alka

2016-01-01

" No plant is an island too …" Plants, though sessile, have developed a unique strategy to counter biotic and abiotic stresses by symbiotically co-evolving with microorganisms and tapping into their genome for this purpose. Soil is the bank of microbial diversity from which a plant selectively sources its microbiome to suit its needs. Besides soil, seeds, which carry the genetic blueprint of plants during trans-generational propagation, are home to diverse microbiota that acts as the principal source of microbial inoculum in crop cultivation. Overall, a plant is ensconced both on the outside and inside with a diverse assemblage of microbiota. Together, the plant genome and the genes of the microbiota that the plant harbors in different plant tissues, i.e., the 'plant microbiome,' form the holobiome which is now considered as unit of selection: 'the holobiont.' The 'plant microbiome' not only helps plants to remain fit but also offers critical genetic variability, hitherto, not employed in the breeding strategy by plant breeders, who traditionally have exploited the genetic variability of the host for developing high yielding or disease tolerant or drought resistant varieties. This fresh knowledge of the microbiome, particularly of the rhizosphere, offering genetic variability to plants, opens up new horizons for breeding that could usher in cultivation of next-generation crops depending less on inorganic inputs, resistant to insect pest and diseases and resilient to climatic perturbations. We surmise, from ever increasing evidences, that plants and their microbial symbionts need to be co-propagated as life-long partners in future strategies for plant breeding. In this perspective, we propose bottom-up approach to co-propagate the co-evolved, the plant along with the target microbiome, through - (i) reciprocal soil transplantation method, or (ii) artificial ecosystem selection method of synthetic microbiome inocula, or (iii) by exploration of microRNA transfer

Selecting an oxygen plant for a copper smelter modernization

Science.gov (United States)

Larson, Kenneth H.; Hutchison, Robert L.

1994-10-01

The selection of an oxygen plant for the Cyprus Miami smelter modernization project began with a good definition of the use requirements and the smelter process variables that can affect oxygen demand. To achieve a reliable supply of oxygen with a reasonable amount of capital, critical equipment items were reviewed and reliability was added through the use of installed spares, purchase of insurance spare parts or the installation of equipment design for 50 percent of the production design such that the plant could operate with one unit while the other unit is being maintained. The operating range of the plant was selected to cover variability in smelter oxygen demand, and it was recognized that the broader operating range sacrificed about two to three percent in plant power consumption. Careful consideration of the plant "design point" was important to both the capital and operating costs of the plant, and a design point was specified that allowed a broad range of operation for maximum flexibility.

A biogeographical study on tropical flora of southern China.

Science.gov (United States)

Zhu, Hua

2017-12-01

The tropical climate in China exists in southeastern Xizang (Tibet), southwestern to southeastern Yunnan, southwestern Guangxi, southern Guangdon, southern Taiwan, and Hainan, and these southern Chinese areas contain tropical floras. I checked and synonymized native seed plants from these tropical areas in China and recognized 12,844 species of seed plants included in 2,181 genera and 227 families. In the tropical flora of southern China, the families are mainly distributed in tropical areas and extend into temperate zones and contribute to the majority of the taxa present. The genera with tropical distributions also make up the most of the total flora. In terms of geographical elements, the genera with tropical Asian distribution constitute the highest proportion, which implies tropical Asian or Indo-Malaysia affinity. Floristic composition and geographical elements are conspicuous from region to region due to different geological history and ecological environments, although floristic similarities from these regions are more than 90% and 64% at the family and generic levels, respectively, but lower than 50% at specific level. These differences in the regional floras could be influenced by historical events associated with the uplift of the Himalayas, such as the southeastward extrusion of the Indochina geoblock, clockwise rotation and southeastward movement of Lanping-Simao geoblock, and southeastward movement of Hainan Island. The similarity coefficients between the flora of southern China and those of Indochina countries are more than 96% and 80% at family and generic levels, indicating their close floristic affinity and inclusion in the same biogeographically floristic unit.

Conifers, angiosperm trees, and lianas: growth, whole-plant water and nitrogen use efficiency, and stable isotope composition ({delta}13C and {delta}18O) of seedlings grown in a tropical environment.

Science.gov (United States)

Cernusak, Lucas A; Winter, Klaus; Aranda, Jorge; Turner, Benjamin L

2008-09-01

Seedlings of several species of gymnosperm trees, angiosperm trees, and angiosperm lianas were grown under tropical field conditions in the Republic of Panama; physiological processes controlling plant C and water fluxes were assessed across this functionally diverse range of species. Relative growth rate, r, was primarily controlled by the ratio of leaf area to plant mass, of which specific leaf area was a key component. Instantaneous photosynthesis, when expressed on a leaf-mass basis, explained 69% of variation in r (P physiological models of tropical forest trees.

Functional strategies of tropical dry forest plants in relation to growth form and isotopic composition

Science.gov (United States)

Santiago, L. S.; Silvera, K.; Andrade, J. L.; Dawson, T. E.

2017-11-01

Tropical dry forests (TDFs) undergo a substantial dry season in which plant species must endure several months of drought. Although TDFs support a diverse array of plant growth forms, it is not clear how they vary in mechanisms for coping with seasonal drought. We measured organic tissue stable isotopic composition of carbon (δ13C) and nitrogen (δ15N) across six plant growth forms including epiphytes, terrestrial succulents, trees, shrubs, herbs, and vines, and oxygen (δ18O) of four growth forms, to distinguish among patterns of resource acquisition and evaluate mechanisms for surviving annual drought in a lowland tropical dry forest in Yucatan, Mexico. Terrestrial succulent and epiphyte δ13C was around -14‰, indicating photosynthesis through the Crassulacean acid metabolism pathway, and along with one C4 herb were distinct from mean values of all other growth forms, which were between -26 and -29‰ indicating C3 photosynthesis. Mean tissue δ15N across epiphytes was -4.95‰ and was significantly lower than all other growth forms, which had values around +3‰. Tissue N concentration varied significantly among growth forms with epiphytes and terrestrial succulents having significantly lower values of about 1% compared to trees, shrubs, herbs and vines, which were around 3%. Tissue C concentration was highest in trees, shrubs and vines, intermediate in herbs and epiphytes and lowest in terrestrial succulents. δ18O did not vary among growth forms. Overall, our results suggest several water-saving aspects of resource acquisition, including the absolute occurrence of CAM photosynthesis in terrestrial succulents and epiphytes, high concentrations of leaf N in some species, which may facilitate CO2 drawdown by photosynthetic enzymes for a given stomatal conductance, and potentially diverse N sources ranging from atmospheric N in epiphytes with extremely depleted δ15N values, and a large range of δ15N values among trees, many of which are legumes and dry season

Timber tree regeneration along abandoned logging roads in a tropical Bolivian forest

DEFF Research Database (Denmark)

Nabe-Nielsen, J.; Severiche, W.; Fredericksen, T.

2007-01-01

Sustainable management of selectively logged tropical forests requires that felled trees are replaced through increased recruitment and growth. This study compares road track and roadside regeneration with regeneration in unlogged and selectively logged humid tropical forest in north-eastern Boli......Sustainable management of selectively logged tropical forests requires that felled trees are replaced through increased recruitment and growth. This study compares road track and roadside regeneration with regeneration in unlogged and selectively logged humid tropical forest in north......-eastern Bolivia. Some species benefited from increased light intensities on abandoned logging roads. Others benefited from low densities of competing vegetation on roads with compacted soils. This was the case for the small-seeded species Ficus boliviana C.C. Berg and Terminalia oblonga (Ruiz & Pav.) Steud. Some...

Hydrolysis of Selected Tropical Plant Wastes Catalyzed by a Magnetic Carbonaceous Acid with Microwave

Science.gov (United States)

Su, Tong-Chao; Fang, Zhen; Zhang, Fan; Luo, Jia; Li, Xing-Kang

2015-12-01

In this study, magnetic carbonaceous acids were synthesized by pyrolysis of the homogeneous mixtures of glucose and magnetic Fe3O4 nanoparticles, and subsequent sulfonation. The synthesis conditions were optimized to obtain a catalyst with both high acid density (0.75 mmol g-1) and strong magnetism [magnetic saturation, Ms = 19.5 Am2 kg-1]. The screened catalyst (C-SO3H/Fe3O4) was used to hydrolyze ball-milled cellulose in a microwave reactor with total reducing sugar (TRS) yield of 25.3% under the best conditions at 190 °C for 3.5 h. It was cycled for at least seven times with high catalyst recovery rate (92.8%), acid density (0.63 mmol g-1) and magnetism (Ms = 12.9 Am2 kg-1), as well as high TRS yield (20.1%) from the hydrolysis of ball-milled cellulose. The catalyst was further successfully tested for the hydrolysis of tropical biomass with high TRS and glucose yields of 79.8% and 58.3% for bagasse, 47.2% and 35.6% for Jatropha hulls, as well as 54.4% and 35.8% for Plukenetia hulls.

Plant operator selection system for evaluating employment candidates' potential for success in electric power plant operations positions

International Nuclear Information System (INIS)

Dunnette, M.D.

1982-01-01

The Plant Operator Selection System is a battery of tests and questionnaires that can be administered to job candidates in less than three hours. Various components of the battery measure what a job candidate has accomplished in previous educational and work situations, how well a candidate compares with others on a number of important aptitudes or abilities, and whether or not a candidate possesses the kind of personal stability required in power plant operations positions. A job candidate's answers to the tests and questionnaires of the Plant Operator Selection System are scored and converted to an OVERALL POTENTIAL INDEX. Values of the OVERALL POTENTIAL INDEX [OPI] range between 0 and 15. Candidates with high OPI values are much more likely to become effective and successful plant operators than candidates with low OPI values. It is possible to estimate the financial advantages to a company of using the Plant Operator Selection System in evaluating candidates for plant operations jobs

Comparative Study of Heavy Metals in Soil and Selected Medicinal Plants

Directory of Open Access Journals (Sweden)

Afzal Shah

2013-01-01

Full Text Available Essential and nonessential heavy metals like iron (Fe, nickel (Ni, manganese (Mn, zinc (Zn, copper (Cu, cadmium (Cd, chromium (Cr, and lead (Pb were analyzed in four selected medicinal plants such as Capparis spinosa, Peganum harmala, Rhazya stricta, and Tamarix articulata by flame atomic absorption spectrophotometer (FAAS. These medicinal plants are extensively used as traditional medicine for treatment of various ailments by local physicians in the area from where these plants were collected. The concentration level of heavy metals in the selected plants was found in the decreasing order as Fe > Zn > Mn > Cu > Ni > Cr > Cd > Pb. The results revealed that the selected medicinal plants accumulate these elements at different concentrations. Monitoring such medicinal plants for heavy metals concentration is of great importance for physicians, health planners, health care professionals, and policymakers in protecting the public from the adverse effects of these heavy metals.

Plant selection and soil legacy enhance long-term biodiversity effects.

Science.gov (United States)

Zuppinger-Dingley, Debra; Flynn, Dan F B; De Deyn, Gerlinde B; Petermann, Jana S; Schmid, Bernhard

2016-04-01

Plant-plant and plant-soil interactions can help maintain plant diversity and ecosystem functions. Changes in these interactions may underlie experimentally observed increases in biodiversity effects over time via the selection of genotypes adapted to low or high plant diversity. Little is known, however, about such community-history effects and particularly the role of plant-soil interactions in this process. Soil-legacy effects may occur if co-evolved interactions with soil communities either positively or negatively modify plant biodiversity effects. We tested how plant selection and soil legacy influence biodiversity effects on productivity, and whether such effects increase the resistance of the communities to invasion by weeds. We used two plant selection treatments: parental plants growing in monoculture or in mixture over 8 yr in a grassland biodiversity experiment in the field, which we term monoculture types and mixture types. The two soil-legacy treatments used in this study were neutral soil inoculated with live or sterilized soil inocula collected from the same plots in the biodiversity experiment. For each of the four factorial combinations, seedlings of eight species were grown in monocultures or four-species mixtures in pots in an experimental garden over 15 weeks. Soil legacy (live inoculum) strongly increased biodiversity complementarity effects for communities of mixture types, and to a significantly weaker extent for communities of monoculture types. This may be attributed to negative plant-soil feedbacks suffered by mixture types in monocultures, whereas monoculture types had positive plant-soil feedbacks, in both monocultures and mixtures. Monocultures of mixture types were most strongly invaded by weeds, presumably due to increased pathogen susceptibility, reduced biomass, and altered plant-soil interactions of mixture types. These results show that biodiversity effects in experimental grassland communities can be modified by the evolution of

Contribution of seagrass plants to CO2 capture in a tropical seagrass meadow under experimental disturbance.

Science.gov (United States)

Deyanova, Diana; Gullström, Martin; Lyimo, Liberatus D; Dahl, Martin; Hamisi, Mariam I; Mtolera, Matern S P; Björk, Mats

2017-01-01

Coastal vegetative habitats are known to be highly productive environments with a high ability to capture and store carbon. During disturbance this important function could be compromised as plant photosynthetic capacity, biomass, and/or growth are reduced. To evaluate effects of disturbance on CO2 capture in plants we performed a five-month manipulative experiment in a tropical seagrass (Thalassia hemprichii) meadow exposed to two intensity levels of shading and simulated grazing. We assessed CO2 capture potential (as net CO2 fixation) using areal productivity calculated from continuous measurements of diel photosynthetic rates, and estimates of plant morphology, biomass and productivity/respiration (P/R) ratios (from the literature). To better understand the plant capacity to coping with level of disturbance we also measured plant growth and resource allocation. We observed substantial reductions in seagrass areal productivity, biomass, and leaf area that together resulted in a negative daily carbon balance in the two shading treatments as well as in the high-intensity simulated grazing treatment. Additionally, based on the concentrations of soluble carbohydrates and starch in the rhizomes, we found that the main reserve sources for plant growth were reduced in all treatments except for the low-intensity simulated grazing treatment. If permanent, these combined adverse effects will reduce the plants' resilience and capacity to recover after disturbance. This might in turn have long-lasting and devastating effects on important ecosystem functions, including the carbon sequestration capacity of the seagrass system.

Knowledge of the Yucatec Maya in seasonal tropical forest management: the forage plants El conocimiento de los mayas yucatecos en el manejo del bosque tropical estacional: las plantas forrajeras

Directory of Open Access Journals (Sweden)

José Salvador Flores

2012-06-01

Full Text Available Indigenous knowledge and the millenary experience in management of natural vegetation on karstic landscapes are important aspects that should be considered in animal production in seasonal tropical environments. The aim of the present work was to make an inventory of native plants associated to soilscapes from seasonal tropical forests from the Yucatán Peninsula that are used as forage by Mayan people. The work was carried out in 27 Mayan communities on karst landscapes in the Yucatán Peninsula as a part of the "Ethnoflora Yucatanense" project of the Universidad Autónoma de Yucatán. Samples were taken of forage plants together with corresponding floristic and ethnobotanical information. Data were processed in EXCEL dynamic tables, grouped by plant family, geoforms and soils, life form and animal consumers. Results indicate that Mayan communities use 196 plant species as forage: 139 herbaceous, 17 shrubs, 35 trees and 2 palms. These plants are fed to cows, pigs, horses, lambs, turkeys, chickens, ducks and pigeons. The use of native forage plants may be an agricultural option both for rural communities and for intensive animal production on silvopastoral systems on karstic tropical landscapes from the Yucatán Peninsula.El conocimiento indígena y la experiencia de milenios de años en el manejo de la vegetación natural en ambientes kársticos tropicales son aspectos importantes que deben ser considerados en la producción animal. El objetivo de este trabajo fue hacer un inventario de las plantas forrajeras nativas de los bosques tropicales estacionales de la península de Yucatán que son utilizadas por los mayas, incluyendo los paisajes edáficos en los que se encuentran las plantas, información que servirá de base para la planeación de las actividades agropecuarias. El trabajo se llevó al cabo en 27 comunidades indígenas mayas, como parte del proyecto "Etnoflora Yucatanense" de la Universidad Autónoma de Yucatán. Las muestras de

Documentation and Nutritional profile of some selected food plants ...

African Journals Online (AJOL)

Documentation and Nutritional profile of some selected food plants of Otwal and Ngai sun counties Oyam District, Northern Uganda. ... However, it should be noted that there is a general decline in the consumption of wild plants, despite the apparent high nutritional values. The conservation of wild food plants is not taking ...

Empirical analysis of selected nuclear power plant maintenance factors and plant safety

International Nuclear Information System (INIS)

Olson, J.; Osborn, R.N.; Thurber, J.A.; Sommers, P.E.; Jackson, D.H.

1985-07-01

This report contains a statistical analysis of the relationship between selected aspects of nuclear power plant maintenance programs and safety related performance. The report identifies a large number of maintenance resources which can be expected to influence maintenance performance and subsequent plant safety performance. The resources for which data were readily available were related statistically to two sets of performance indicators: maintenance intermediate safety indicators and final safety performance indicators. The results show that the administrative structure of the plant maintenance program is a significant predictor of performance on both sets of indicators

Selection of Possible Candidate Area for Nuclear Power Plant in Johor, Malaysia

International Nuclear Information System (INIS)

Nor Afifah Basri; Ahmad Termizi Ramli

2012-01-01

Nuclear power is considered as one of the best option for future energy development in Malaysia. Since Malaysia has no experience in nuclear energy generation, commissioning the first nuclear power plant needs tremendous effort in various aspects. Site selection is one of important step in nuclear power plant commissioning process. This paper proposes candidate sites for nuclear power plant in Mersing, Kota Tinggi, Muar and Batu Pahat district in Johor, Malaysia. The candidate selection process uses the IAEA document and AELB guideline as main reference, supported by site selection procedure by various countries. MapInfo Professional software was used to simulate the selection process for candidate areas for the nuclear power plant. This paper concluded that Tenggaroh and Jemaluang area are the most suitable area for nuclear power plant facilities in Johor, Malaysia. (Author)

On statistical selection in plant breeding

NARCIS (Netherlands)

Dourleijn, C.J.

1993-01-01

The ultimate goal of plant breeding is the development of new varieties. An important phase in the development process is testing and selecting potential new varieties. The varieties are tested by means of experiments at various sites, (sometimes) in several years. The observations from the

Soil to plant transfer values of 137 Cs in soils of tropical agro-ecological systems

International Nuclear Information System (INIS)

Wasserman, Maria Angelica; Ferreira, Ana Cristina Melo; Conti, Claudio Carvalho; Rochedo, Elaine Rua Rodriguez; Bartoly, Flavia; Viana, Aline Gonzalez; Moura, Glaucio Pereira; Poquet, Isabel; Perez, Daniel Vidal

2002-01-01

Recent radioecological studies have showed that some ecosystems present more suitable conditions for soil to plant transfer of some radionuclides, while others present lower transfer when compared with average values. Due to the difficulty to generate, experimentally, soil to plant transfer factors enough to cover the totality of existing soil and vegetation types, an alternative way has been the use of soil to reference plant transfer factor determined in various ecosystems. Trough the use of conversion factors, the reference transfer factor can be converted in values of transfer factor specific for a specific type of crop. These values can be used regionally to improve dose calculation and models for radiological risk assessments. This work presents experimental data for 137 Cs for reference crops grown up in Oxisol, Ultisol and Alfisol. These results allow the assessment of sensibility of main Brazilian soils regarding a radiological contamination with 137 Cs and provide regional parameters values. The results obtained in soils of tropical climate validate the international methodology aiming to derive generic transfer factor values for 137 Cs in reference crops based on a few soil properties such as fertility, pH and organic matter content. (author)

Microbiome selection could spur next-generation plant breeding strategies

Directory of Open Access Journals (Sweden)

Murali Gopal

2016-12-01

Full Text Available Plants, though sessile, have developed a unique strategy to counter biotic and abiotic stresses by symbiotically co-evolving with microorganisms and tapping into their genome for this purpose. Soil is the bank of microbial diversity from which a plant selectively sources its microbiome to suit its needs. Besides soil, seeds, which carry the genetic blueprint of plants during trans-generational propagation, are home to diverse microbiota that acts as the principal source of microbial inoculum in crop cultivation. Overall, a plant is ensconced both on the outside and inside with a diverse assemblage of microbiota. Together, the plant genome and the genes of the microbiota that the plant harbours in different plant tissues i.e the ‘plant microbiome’, form the holobiome which is now considered as unit of selection: ‘the holobiont’. The ‘plant microbiome’ not only helps plants to remain fit but also offers critical genetic variability, hitherto, not employed in the breeding strategy by plant breeders, who traditionally have exploited the genetic variability of the host for developing high yielding or disease tolerant or drought resistant varieties. This fresh knowledge of the microbiome, particularly of the rhizosphere, offering genetic variability to plants, opens up new horizons for breeding that could usher in cultivation of next-generation crops depending less on inorganic inputs, resistant to insect pest and diseases and resilient to climatic perturbations. We surmise, from ever increasing evidences, that plants and their microbial symbionts need to be co-propagated as life-long partners in future strategies for plant breeding.

Rapid and sensitive detection of potyvirus infecting tropical tuber ...

African Journals Online (AJOL)

Yomi

2012-01-16

Jan 16, 2012 ... tropical tuber crops using genus specific primers and probes. Binoy Babu ... diagnosis of plant viral diseases (Clark and Adams, 1977;. Flegg and Clark ..... Network Project on Diagnostics of Emerging Plant. Viruses” and the ...

Radiation induced mutations for plant selection

International Nuclear Information System (INIS)

Brunner, H.

1994-01-01

The successful use of plant breeding for improving crops requires the existence of genetic variation of useful traits. Unfortunately, the desired variation is often lacking. However, radiation can be used to induce mutations and thereby generate genetic variation from which desired mutants may be selected. Mutation induction has become a proven way of creating variation within a crop variety. It offers the possibility of inducing desired attributes that either cannot be expressed in nature or have been lost during evolution. More than 1700 mutant cultivars of crop plants with significantly improved attributes such as increased yield, improved quality, disease and stress resistance, have been released worldwide in the last thirty years. The Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture has contributed to these achievements through the promotion of research and development in mutation breeding techniques using nuclear and related biotechnological methods and the provision of in plant breeding is then transferred to Member States of the IAEA and the FAO through training in mutation breeding methods and the provision of technical advice. Moreover, radiation treatment services are provided to foster applications of nuclear techniques in crop improvement programmes of member states and more specifically to render direct support to plant breeders by efficient generation of mutations. Plant materials are standardized prior to radiation exposure to warrant reproducibility of the induced effects within practical limits and a radiosensitivity test is implemented to affirm useful doses for applied objectives of a request. This review deals with irradiation methods applied at the IAEA laboratories for the efficient induction of mutations in seeds, vegetative propagules and tissue and cell cultures and the establishment of genetically variable populations upon which selection of desired traits can be based. 3 tabs., 18 refs. (author)

Historical plant cost and annual production expenses for selected electric plants, 1982

International Nuclear Information System (INIS)

1984-01-01

This publication is a composite of the two prior publications, Hydroelectric Plant Construction Cost and Annual Production Expenses and Thermal-Electric Plant Construction Cost and Annual Production Expenses. Beginning in 1979, Thermal-Electric Plant Construction Cost and Annual Production Expenses contained information on both steam-electric and gas-turbine electric plant construction cost and annual production expenses. The summarized historical plant cost described under Historical Plant Cost in this report is the net cumulative-to-date actual outlays or expenditures for land, structures, and equipment to the utility. Historical plant cost is the initial investment in plant (cumulative to the date of initial commercial operation) plus the costs of all additions to the plant, less the value of retirements. Thus, historical plant cost includes expenditures made over several years, as modifications are made to the plant. Power Production Expenses is the reporting year's plant operation and maintenance expenses, including fuel expenses. These expenses do not include annual fixed charges on plant cost (capital costs) such as interest on debt, depreciation or amortization expenses, and taxes. Consequently, total production expenses and the derived unit costs are not the total cost of producing electric power at the various plants. This publication contains data on installed generating capacity, net generation, net capability, historical plant cost, production expenses, fuel consumption, physical and operating plant characteristics, and other relevant statistical information for selected plants

Fungal and Oomycete Diseases of Tropical Tree Fruit Crops.

Science.gov (United States)

Drenth, André; Guest, David I

2016-08-04

The tropics produce a range of fruit from tree crops that cannot be grown in colder climates. Bananas, mangos, several nuts, spices, coffee, and cacao are widely traded and much sought after around the world. However, the sustainable production of these tropical tree fruit crops faces significant challenges. Among these, losses due to pests and diseases play a large part in reducing yields, quality, and profitability. Using bananas and cacao as key examples, we outline some of the reasons fungal and oomycete diseases cause such significant losses to tropical tree crops. Cultivation of monocultures derived from limited genetic diversity, environmental conditions conducive for disease development, high levels of disease incidence and severity, a lack of disease resistance in planting materials, shortages of labor, and inadequate infrastructure and investment pose significant challenges, especially for smallholder producers. The expansion of travel and trade has given rise to emerging infectious plant diseases that add further insecurity and pressure. We conclude that holistic actions are needed on multiple fronts to address the growing problem of disease in tropical fruit tree crops.

CARBON SEQUESTRATION AND PLANT COMMUNITY DYNAMICS FOLLOWING REFORESTATION OF TROPICAL PASTURE.

Science.gov (United States)

WHENDEE L. SILVER; LARA M. KUEPPERS; ARIEL E. LUGO; REBECCA OSTERTAG; VIRGINIA MATZEK

2004-01-01

Conversion of abandoned cattle pastures to secondary forests and plantations in the tropics has been proposed as a means to increase rates of carbon (C) sequestration from the atmosphere and enhance local biodiversity. We used a long-term tropical reforestation project (55–61 yr) to estimate rates of above- and belowground C sequestration and to investigate the impact...

Coupled nutrient cycling determines tropical forest trajectory under elevated CO2.

Science.gov (United States)

Bouskill, N.; Zhu, Q.; Riley, W. J.

2017-12-01

Tropical forests have a disproportionate capacity to affect Earth's climate relative to their areal extent. Despite covering just 12 % of land surface, tropical forests account for 35 % of global net primary productivity and are among the most significant of terrestrial carbon stores. As atmospheric CO2 concentrations increase over the next century, the capacity of tropical forests to assimilate and sequester anthropogenic CO2 depends on limitation by multiple factors, including the availability of soil nutrients. Phosphorus availability has been considered to be the primary factor limiting metabolic processes within tropical forests. However, recent evidence points towards strong spatial and temporal co-limitation of tropical forests by both nitrogen and phosphorus. Here, we use the Accelerated Climate Modeling for Energy (ACME) Land Model (ALMv1-ECA-CNP) to examine how nutrient cycles interact and affect the trajectory of the tropical forest carbon sink under, (i) external nutrient input, (ii) climate (iii) elevated CO2, and (iv) a combination of 1-3. ALMv1 includes recent theoretical advances in representing belowground competition between roots, microbes and minerals for N and P uptake, explicit interactions between the nitrogen and phosphorus cycles (e.g., phosphatase production and nitrogen fixation), the dynamic internal allocation of plant N and P resources, and the integration of global datasets of plant physiological traits. We report nutrient fertilization (N, P, N+P) predictions for four sites in the tropics (El Verde, Puerto Rico, Barro Colorado Island, Panama, Manaus, Brazil and the Osa Peninsula, Coast Rica) to short-term nutrient fertilization (N, P, N+P), and benchmarking of the model against a meta-analysis of forest fertilization experiments. Subsequent simulations focus on the interaction of the carbon, nitrogen, and phosphorus cycles across the tropics with a focus on the implications of coupled nutrient cycling and the fate of the tropical

Phytoremediation in the tropics - influence of heavy crude oil on root morphological characteristics of graminoids

International Nuclear Information System (INIS)

Merkl, Nicole; Schultze-Kraft, Rainer; Infante, Carmen

2005-01-01

When studying species for phytoremediation of petroleum-contaminated soils, one of the main traits is the root zone where enhanced petroleum degradation takes place. Root morphological characteristics of three tropical graminoids were studied. Specific root length (SRL), surface area, volume and average root diameter (ARD) of plants grown in crude oil-contaminated and uncontaminated soil were compared. Brachiaria brizantha and Cyperus aggregatus showed coarser roots in polluted soil compared to the control as expressed in an increased ARD. B. brizantha had a significantly larger specific root surface area in contaminated soil. Additionally, a shift of SRL and surface area per diameter class towards higher diameters was found. Oil contamination also caused a significantly smaller SRL and surface area in the finest diameter class of C. aggregatus. The root structure of Eleusine indica was not significantly affected by crude oil. Higher specific root surface area was related to higher degradation of petroleum hydrocarbons found in previous studies. - Describing the effect of crude oil on root morphology of tropical graminoids the work assists in the selection of plant species for phytoremediation of oil-contaminated soils

Phytoremediation in the tropics - influence of heavy crude oil on root morphological characteristics of graminoids

Energy Technology Data Exchange (ETDEWEB)

Merkl, Nicole [Institute of Plant Production and Agroecology in the Tropics and Subtropics, Department of Biodiversity and Land Rehabilitation, University of Hohenheim, D-70593 Stuttgart (Germany) and PDVSA - Intevep, Centro de Investigacion y Apoyo Tecnologico de Petroleos de Venezuela S.A., Departamento de Ecologia y Ambiente, P.O. Box 76343, Caracas 1070-A (Venezuela)]. E-mail: nmerkl@uni-hohenheim.de; Schultze-Kraft, Rainer [Institute of Plant Production and Agroecology in the Tropics and Subtropics, Department of Biodiversity and Land Rehabilitation, University of Hohenheim, D-70593 Stuttgart (Germany)]. E-mail: rsk@uni-hohenheim.de; Infante, Carmen [PDVSA - Intevep, Centro de Investigacion y Apoyo Tecnologico de Petroleos de Venezuela S.A., Departamento de Ecologia y Ambiente, P.O. Box 76343, Caracas 1070-A (Venezuela) and Universidad Simon Bolivar (USB), FUNINDES, Unidad de Gestion Ambiental, Caracas (Venezuela)]. E-mail: luchoben@cantv.net

2005-11-15

When studying species for phytoremediation of petroleum-contaminated soils, one of the main traits is the root zone where enhanced petroleum degradation takes place. Root morphological characteristics of three tropical graminoids were studied. Specific root length (SRL), surface area, volume and average root diameter (ARD) of plants grown in crude oil-contaminated and uncontaminated soil were compared. Brachiaria brizantha and Cyperus aggregatus showed coarser roots in polluted soil compared to the control as expressed in an increased ARD. B. brizantha had a significantly larger specific root surface area in contaminated soil. Additionally, a shift of SRL and surface area per diameter class towards higher diameters was found. Oil contamination also caused a significantly smaller SRL and surface area in the finest diameter class of C. aggregatus. The root structure of Eleusine indica was not significantly affected by crude oil. Higher specific root surface area was related to higher degradation of petroleum hydrocarbons found in previous studies. - Describing the effect of crude oil on root morphology of tropical graminoids the work assists in the selection of plant species for phytoremediation of oil-contaminated soils.

No evidence that boron influences tree species distributions in lowland tropical forests of Panama.

Science.gov (United States)

Turner, Benjamin L; Zalamea, Paul-Camilo; Condit, Richard; Winter, Klaus; Wright, S Joseph; Dalling, James W

2017-04-01

It was recently proposed that boron might be the most important nutrient structuring tree species distributions in tropical forests. Here we combine observational and experimental studies to test this hypothesis for lowland tropical forests of Panama. Plant-available boron is uniformly low in tropical forest soils of Panama and is not significantly associated with any of the > 500 species in a regional network of forest dynamics plots. Experimental manipulation of boron supply to seedlings of three tropical tree species revealed no evidence of boron deficiency or toxicity at concentrations likely to occur in tropical forest soils. Foliar boron did not correlate with soil boron along a local scale gradient of boron availability. Fifteen years of boron addition to a tropical forest increased plant-available boron by 70% but did not significantly change tree productivity or boron concentrations in live leaves, wood or leaf litter. The annual input of boron in rainfall accounts for a considerable proportion of the boron in annual litterfall and is similar to the pool of plant-available boron in the soil, and is therefore sufficient to preclude boron deficiency. We conclude that boron does not influence tree species distributions in Panama and presumably elsewhere in the lowland tropics. No claim to original US government works New Phytologist © 2016 New Phytologist Trust.

ANTIOXIDANT AND ANTIFUNGAL ACTIVITY OF SELECTED MEDICINAL PLANT EXTRACTS AGAINST PHYTOPATHOGENIC FUNGI.

Science.gov (United States)

Mahlo, Salome Mamokone; Chauke, Hasani Richard; McGaw, Lyndy; Eloff, Jacobus

2016-01-01

Medicinal plants are used by many ethnic groups as a source of medicine for the treatment of various ailments in both humans and domestic animals. These plants produce secondary metabolites that have antimicrobial properties, thus screening of medicinal plants provide another alternative for producing chemical fungicides that are relatively non-toxic and cost-effective. Leaf extracts of selected South African plant species ( Bucida buceras, Breonadia salicina, Harpephyllum caffrum, Olinia ventosa, Vangueria infausta and Xylotheca kraussiana ) were investigated for activity against selected phytopathogenic fungi ( Aspergillus niger, Aspergillus parasiticus, Colletotricum gloeosporioides, Penicillium janthinellum, P. expansum, Trichoderma harzianum and Fusarium oxysporum ). These plant fungal pathogens causes major economic losses in fruit industry such as blue rot on nectaries and postharvest disease in citrus. Plant species were selected from 600 evaluated inter alia, against two animal fungal pathogens ( Candida albicans and Cryptococcus neoformans ). Antioxidant activity of the selected plant extracts were investigated using a qualitative assay (2, 2-diphenyl-1-picrylhydrazyl (DPPH)). Bioautography assay was used to determine the number of antifungal compounds in plant extracts. All plant extracts were active against the selected plant phytopathogenic fungi. Moreover, Bucida buceras had the best antifungal activity against four of the fungi, with minimum inhibitory concentration (MIC) values as low as 0.02 mg/ml and 0.08 mg/ml against P. expansum, P. janthinellum, T. harzianum and F. oxysporum . The plant extracts of five plant species did not possess strong antioxidant activity. However, methanol extract of X. kraussiana was the most active radical scavenger in the DPPH assay amongst the six medicinal plants screened. No antifungal compounds were observed in some of the plant extracts with good antifungal activity as shown in the microdilution assay, indicating

Rethinking plant functional types in Earth System Models: pan-tropical analysis of tree survival across environmental gradients

Science.gov (United States)

Johnson, D. J.; Needham, J.; Xu, C.; Davies, S. J.; Bunyavejchewin, S.; Giardina, C. P.; Condit, R.; Cordell, S.; Litton, C. M.; Hubbell, S.; Kassim, A. R. B.; Shawn, L. K. Y.; Nasardin, M. B.; Ong, P.; Ostertag, R.; Sack, L.; Tan, S. K. S.; Yap, S.; McDowell, N. G.; McMahon, S.

2016-12-01

Terrestrial carbon cycling is a function of the growth and survival of trees. Current model representations of tree growth and survival at a global scale rely on coarse plant functional traits that are parameterized very generally. In view of the large biodiversity in the tropical forests, it is important that we account for the functional diversity in order to better predict tropical forest responses to future climate changes. Several next generation Earth System Models are moving towards a size-structured, trait-based approach to modelling vegetation globally, but the challenge of which and how many traits are necessary to capture forest complexity remains. Additionally, the challenge of collecting sufficient trait data to describe the vast species richness of tropical forests is enormous. We propose a more fundamental approach to these problems by characterizing forests by their patterns of survival. We expect our approach to distill real-world tree survival into a reasonable number of functional types. Using 10 large-area tropical forest plots that span geographic, edaphic and climatic gradients, we model tree survival as a function of tree size for hundreds of species. We found surprisingly few categories of size-survival functions emerge. This indicates some fundamental strategies at play across diverse forests to constrain the range of possible size-survival functions. Initial cluster analysis indicates that four to eight functional forms are necessary to describe variation in size-survival relations. Temporal variation in size-survival functions can be related to local environmental variation, allowing us to parameterize how demographically similar groups of species respond to perturbations in the ecosystem. We believe this methodology will yield a synthetic approach to classifying forest systems that will greatly reduce uncertainty and complexity in global vegetation models.

Coevolutionary arms race versus host defense chase in a tropical herbivore-plant system.

Science.gov (United States)

Endara, María-José; Coley, Phyllis D; Ghabash, Gabrielle; Nicholls, James A; Dexter, Kyle G; Donoso, David A; Stone, Graham N; Pennington, R Toby; Kursar, Thomas A

2017-09-05

Coevolutionary models suggest that herbivores drive diversification and community composition in plants. For herbivores, many questions remain regarding how plant defenses shape host choice and community structure. We addressed these questions using the tree genus Inga and its lepidopteran herbivores in the Amazon. We constructed phylogenies for both plants and insects and quantified host associations and plant defenses. We found that similarity in herbivore assemblages between Inga species was correlated with similarity in defenses. There was no correlation with phylogeny, a result consistent with our observations that the expression of defenses in Inga is independent of phylogeny. Furthermore, host defensive traits explained 40% of herbivore community similarity. Analyses at finer taxonomic scales showed that different lepidopteran clades select hosts based on different defenses, suggesting taxon-specific histories of herbivore-host plant interactions. Finally, we compared the phylogeny and defenses of Inga to phylogenies for the major lepidopteran clades. We found that closely related herbivores fed on Inga with similar defenses rather than on closely related plants. Together, these results suggest that plant defenses might be more evolutionarily labile than the herbivore traits related to host association. Hence, there is an apparent asymmetry in the evolutionary interactions between Inga and its herbivores. Although plants may evolve under selection by herbivores, we hypothesize that herbivores may not show coevolutionary adaptations, but instead "chase" hosts based on the herbivore's own traits at the time that they encounter a new host, a pattern more consistent with resource tracking than with the arms race model of coevolution.

Antibacterial activity of some selected plants traditionally used as ...

African Journals Online (AJOL)

Antibacterial activity of some selected plants traditionally used as medicine in Manipur. ... Hence these plants can be used to discover bioactive natural products that may serve as leads in the development of the new pharmaceuticals. Keywords: Antibacterial, human pathogens, methanolic extract, traditional medicine

Germination, survival and growth of three vascular plants on biological soil crusts from a Mexican tropical desert.

Science.gov (United States)

Godínez-Alvarez, H; Morín, C; Rivera-Aguilar, V

2012-01-01

Information about the effects of biological soil crusts (BSC) on germination, seedling survival and growth of vascular plants is controversial because they can have positive, neutral or negative effects. This controversy may be because most studies conducted until now have just analysed one or two recruitment stages independently. To understand the BSC effects on vascular plants, it is necessary to consider each stage of the recruitment process and synthesise all this information. The goal of this study was twofold. First, we analyse germination, seedling survival and growth of three vascular plants (Agave marmorata, Prosopis laevigata and Neobuxbaumia tetetzo) on BSC (cyanobacteria and mixed crust) from a tropical desert region of south-central México. Second, we synthesise the information to determine the total effect of BSC on plant species performance. We conducted experiments under controlled conditions to evaluate the proportion of germinated seeds, proportion of surviving seedlings and seedling dry weight in BSC and bare soil. Results showed that BSC have different effects on germination, seedling survival and growth of plant species. Plant species performance was qualitatively higher on BSC than bare soil. The highest performance of A. marmorata and P. laevigata was observed on cyanobacteria and mixed crusts, respectively. The highest performance of N. tetetzo was on both crust types. © 2011 German Botanical Society and The Royal Botanical Society of the Netherlands.

Final report on a field study of soil-to-plant transfer radioactive caesium, strontium and zinc in Tropical Northern Australia

International Nuclear Information System (INIS)

Twining, J.; Payne, T.; Russell, R.; Wilde, K; McOrist, G.; Wong, H.; Shotton, P.; Tagami, K.; Itakura, T.

2003-01-01

Soil-to-plant radionuclide transfer factors for cesium ( 134 Cs), strontium ( 85 Sr) and zinc ( 65 Zn) into sorghum and mung plants grown in tropical Australia have been determined over a four-year study period. The crops were grown on two types of red earth soils. Transfer factors for Cs and Sr are not substantially different from the expected values based on previous studies, reported in the general literature and compiled in the IUR database, mainly performed within temperate climates. In contrast, the values for zinc (Zn) are more than an order of magnitude greater than anticipated. Most of the radioactivity added to the soils has been retained in the top 5 cm of both soils. There has been a general decline in soil-to-plant transfer of Cs and Zn as time has increased

Biometrical applications in tropical pasture and agro-pastoral research

NARCIS (Netherlands)

Amézquita, M.C.

2001-01-01

"Biometrical Applications in Tropical Pasture and Agro-pastoral Research" illustrates, through selected Case Studies, the contribution of Biometry to pasture and agro-pastoral research in Tropical Latin America ( TLA ) in the last

Towards restoration of Hawaiian tropical dry forests: the Kaupulehu outplanting programme

Science.gov (United States)

Susan Cordell; Moana McClellan; Yvonne Yarber Carter; Lisa J. Hadway

2008-01-01

Hawaiian tropical dry forests contain diverse assemblages of woody canopy species, including many endemic and endangered species that warrant conservation attention before completely disappearing. Today, tropical dry forests in Hawaii are not viable ecosystems. Poor land use practices, fragmentation, non-native plant invasions, and inadequate native vegetation...

Tropical pasture legumes in southern Africa: A review. | J.H. | African ...

African Journals Online (AJOL)

Clipping trials have indicated that the use of tropical legumes could possibly be extended into drier areas and areas experiencing extremes of temperature. More intensive plant introduction, breeding and evaluation programmes are needed if the full potential of tropical legumes is to be realised. Keywords: adaptation ...

Congruent biogeographical disjunctions at a continent-wide scale: Quantifying and clarifying the role of biogeographic barriers in the Australian tropics

Science.gov (United States)

Crisp, Michael D.; Cook, Dianne H.; Cook, Lyn G.

2017-01-01

Aim To test whether novel and previously hypothesized biogeogaphic barriers in the Australian Tropics represent significant disjunction points or hard barriers, or both, to the distribution of plants. Location Australian tropics: Australian Monsoon Tropics and Australian Wet Tropics. Methods The presence or absence of 6,861 plant species was scored across 13 putative biogeographic barriers in the Australian Tropics, including two that have not previously been recognised. Randomizations of these data were used to test whether more species showed disjunctions (gaps in distribution) or likely barriers (range limits) at these points than expected by chance. Results Two novel disjunctions in the Australian Tropics flora are identified in addition to eleven putative barriers previously recognized for animals. Of these, eleven disjunction points (all within the Australian Monsoon Tropics) were found to correspond to range-ending barriers to a significant number of species, while neither of the two disjunctions found within the Australian Wet Tropics limited a significant number of species’ ranges. Main conclusions Biogeographic barriers present significant distributional limits to native plant species in the Australian Monsoon Tropics but not in the Australian Wet Tropics. PMID:28376094

Research on professional adaptability psychological selection indices of nuclear power plant operators

International Nuclear Information System (INIS)

Liu Jingquan; Li Zhe; Li Maoyou

2010-01-01

Based on the analysis of the work characteristics of nuclear power plant operators and the comparison of professional psychological selection indices for different occupations, the indices of psychological selection system which is applicable to nuclear power plant operators are proposed in this paper, using the method named 'taking classes,cross-comparison'. The index results of the suggested psychological selection system reflects all the professional requirements on the nuclear power plant operators, which can also be used for the recruitment, training and the retraining programs for operators. (authors)

Healthful and nutritional components in select Florida tropical fruits

Science.gov (United States)

Fourteen tropical fruits from south Florida (red guava, white guava, carambola, red pitaya (red dragon), white pitaya (white dragon), mamey, sapodilla, lychee, longan, green mango, ripe mango, green papaya and ripe papaya) were evaluated for phenolic compounds, antioxidant activity, ascorbic acid (v...

Terrestrial radiation level in selected asphalt plants in Port Harcourt ...

African Journals Online (AJOL)

Terrestrial radiation level in selected asphalt plants in Port Harcourt, Nigeria. ... An environmental radiation survey in asphalt processing plants in Rivers State was been carried out ... Therefore the results show significant radiological risk.

Diversity in plant hydraulic traits explains seasonal and inter-annual variations of vegetation dynamics in seasonally dry tropical forests.

Science.gov (United States)

Xu, Xiangtao; Medvigy, David; Powers, Jennifer S; Becknell, Justin M; Guan, Kaiyu

2016-10-01

We assessed whether diversity in plant hydraulic traits can explain the observed diversity in plant responses to water stress in seasonally dry tropical forests (SDTFs). The Ecosystem Demography model 2 (ED2) was updated with a trait-driven mechanistic plant hydraulic module, as well as novel drought-phenology and plant water stress schemes. Four plant functional types were parameterized on the basis of meta-analysis of plant hydraulic traits. Simulations from both the original and the updated ED2 were evaluated against 5 yr of field data from a Costa Rican SDTF site and remote-sensing data over Central America. The updated model generated realistic plant hydraulic dynamics, such as leaf water potential and stem sap flow. Compared with the original ED2, predictions from our novel trait-driven model matched better with observed growth, phenology and their variations among functional groups. Most notably, the original ED2 produced unrealistically small leaf area index (LAI) and underestimated cumulative leaf litter. Both of these biases were corrected by the updated model. The updated model was also better able to simulate spatial patterns of LAI dynamics in Central America. Plant hydraulic traits are intercorrelated in SDTFs. Mechanistic incorporation of plant hydraulic traits is necessary for the simulation of spatiotemporal patterns of vegetation dynamics in SDTFs in vegetation models. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

Sorption-desorption of radiocesium interception potential in tropical soils

International Nuclear Information System (INIS)

Roque, Mario L.; Boaretto, Rodrigo M.; Boaretto, Antonio E.; Smolders, Erik E.T.

2000-01-01

A study of sorption of radiocaesium in soils of tropical climate (Brazil) was carried. The values of definitive fixation of the radiocaesium were determined by analytic methodology of sorption-desorption and the availability to plants were calculated by the determination of radiocesium interception potential (RIP). The values of sorption varied from 1,2 to 74,8% and the fixation varied from 3,2% to 32,2%. The results shown that the radiocaesium did remain adsorbed mainly to the frayed edge site. The low values of interception potential and definitive fixation demonstrated high capacity of the tropical soils in disposal the radionuclide for the solution and, consequently, to plants. (author)

Plant available nitrogen from anaerobically digested sludge and septic tank sludge applied to crops grown in the tropics.

Science.gov (United States)

Sripanomtanakorn, S; Polprasert, C

2002-04-01

Agricultural land is an attractive alternative for the disposal of biosolids since it utilises the recyclable nutrients in the production of crops. In Thailand and other tropical regions, limited field-study information exists on the effect of biosolids management strategies on crop N utilisation and plant available N (PAN) of biosolids. A field study was conducted to quantify the PAN of the applied biosolids, and to evaluate the N uptake rates of some tropical crops. Sunflower (Helianthus annuus) and tomato (Lycopersicon esculentum) were chosen in this study. Two types of biosolids used were: anaerobically digested sludge and septic tank sludge. The soil is acid sulfate and is classified as Sulfic Tropaquepts with heavy clay in texture. The anaerobically digested sludge applied rates were: 0, 156 and 312 kg N ha(-1) for the sunflower plots, and 0, 586, and 1172 kg N ha(-1) for the tomato plots. The septic tank sludge applied rates were: 0, 95 and 190 kg N ha(-1) for the sunflower plots, and 0, 354 and 708 kg N ha(-1) for the tomato plots, respectively. The results indicated the feasibility of applying biosolids to grow tropical crops. The applications of the anaerobically digested sludge and the septic tank sludge resulted in the yields of sunflower seeds and tomato fruits and the plant N uptakes comparable or better than that applied with only the chemical fertiliser. The estimated PAN of the anaerobically digested sludge was about 27-42% of the sludge organic N during the growing season. For the septic tank sludge, the PAN was about 15-58% of the sludge organic N. It is interesting to observe that an increase of the rate of septic tank sludge incorporated into this heavy clay soil under the cropping system resulted in the decrease of N mineralisation rate. This situation could cause the reduction of yield and N uptake of crops.

Positions of human dwellings affect few tropical diseases near ...

African Journals Online (AJOL)

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Some factors that possibly affect tropical disease distribution was investigated in about 500 randomize human dwellings. The studied factors include wild animals, domestic animals, wild plants, cultivated plants, nature of soil, nature of water, positions of human dwellings, nature of building material and position of animal ...

Hydrocarbons from plants: Analytical methods and observations

Energy Technology Data Exchange (ETDEWEB)

Calvin, Melvin

1980-11-01

We have suggested that certain plants rich in hydrocarbon-like materials might be cultivated for renewable photosynthetic products. Two species were selected for experimental plantations: Euphorbia lathyris, an annual from seed and Euphorbia tirucalli, a perennial from cuttings, The yield from each species is over 10 barrels of oil/acre/year without genetic or agronomic improvement. In addition to plants, there are trees, such as species of Copaifera in Brazil and other tropical areas, which produce a diesel-like oil upon tapping. Each tree produces approximately 40 liters of hydrocarbon per year, and this material can be used directly by a diesel-powered car. Further efforts to develop plants as alternate energy sources are underway, as well as a continuing search for additional plant species throughout the world which have a similar capability.

Antibacterial activity of selected Myanmar medicinal plants

International Nuclear Information System (INIS)

Nwe Yee Win; Nyunt Wynn; Mar Mar Nyein; Win Myint; Saw Hla Myint; Myint Khine

2001-01-01

Thirteen plants which are traditionally used for the treatment of dysentery and diarrhoea in Myanmar were selected and tested for antibacterial activity by using agar disc diffusion technique. Polar and nonpolar solvents were employed for extraction of plants. The minimum inhibitory concentration (MIC) of the extracts with the most significant predominant activity were evaluated by plate dilution method. The plants Eugenia jambolana, Quisqualis indica, Leucaena glauca and Euphorbia splendens var. 1 were found to show significant antibacterial activity. It was also observed that extracts using nonpolar solvents did not show any antibacterial activity and extracts using polar solvents showed antibacterial activity on tested bacteria, indicating that the active chemical compound responsible for the antibacterial action must be a polar soluble compound. (author)

Is the poleward migration of tropical cyclone maximum intensity associated with a poleward migration of tropical cyclone genesis?

Science.gov (United States)

Daloz, Anne Sophie; Camargo, Suzana J.

2018-01-01

A recent study showed that the global average latitude where tropical cyclones achieve their lifetime-maximum intensity has been migrating poleward at a rate of about one-half degree of latitude per decade over the last 30 years in each hemisphere. However, it does not answer a critical question: is the poleward migration of tropical cyclone lifetime-maximum intensity associated with a poleward migration of tropical cyclone genesis? In this study we will examine this question. First we analyze changes in the environmental variables associated with tropical cyclone genesis, namely entropy deficit, potential intensity, vertical wind shear, vorticity, skin temperature and specific humidity at 500 hPa in reanalysis datasets between 1980 and 2013. Then, a selection of these variables is combined into two tropical cyclone genesis indices that empirically relate tropical cyclone genesis to large-scale variables. We find a shift toward greater (smaller) average potential number of genesis at higher (lower) latitudes over most regions of the Pacific Ocean, which is consistent with a migration of tropical cyclone genesis towards higher latitudes. We then examine the global best track archive and find coherent and significant poleward shifts in mean genesis position over the Pacific Ocean basins.

Nitrogen to phosphorus ratio of plant biomass versus soil solution in a tropical pioneer tree, Ficus insipida.

Science.gov (United States)

Garrish, Valerie; Cernusak, Lucas A; Winter, Klaus; Turner, Benjamin L

2010-08-01

It is commonly assumed that the nitrogen to phosphorus (N:P) ratio of a terrestrial plant reflects the relative availability of N and P in the soil in which the plant grows. Here, this was assessed for a tropical pioneer tree, Ficus insipida. Seedlings were grown in sand and irrigated with nutrient solutions containing N:P ratios ranging from 100. The experimental design further allowed investigation of physiological responses to N and P availability. Homeostatic control over N:P ratios was stronger in leaves than in stems or roots, suggesting that N:P ratios of stems and roots are more sensitive indicators of the relative availability of N and P at a site than N:P ratios of leaves. The leaf N:P ratio at which the largest plant dry mass and highest photosynthetic rates were achieved was approximately 11, whereas the corresponding whole-plant N:P ratio was approximately 6. Plant P concentration varied as a function of transpiration rate at constant nutrient solution P concentration, possibly due to transpiration-induced variation in the mass flow of P to root surfaces. The transpiration rate varied in response to nutrient solution N concentration, but not to nutrient solution P concentration, demonstrating nutritional control over transpiration by N but not P. Water-use efficiency varied as a function of N availability, but not as a function of P availability.

Herbaceous land plants as a renewable energy source for Puerto Rico

Energy Technology Data Exchange (ETDEWEB)

Alexander, A.G.

1980-01-01

Herbaceous tropical plants are a renewable energy source of major importance to many tropical nations. They convert the radiant energy of sunlight to chemical energy, which is stored in plant tissues (cellulose, hemicellulose, lignin) and fermentable solids (sugars, starches). Because all tropical plants do this - even those commonly regarded as weeds - they constitute an inexpensive, renewable, and domestic alternative to foreign fossil energy. The vast majority of herbaceous tropical plants have never been cultivated for food, fiber, or energy. A major screening program would be needed to identify superior species and the most effective roles they can play in a domestic energy industry. Other herbaceous plants, such as sugarcane and tropical forage grasses, have been cultivated for centuries as agricultural commodities. As energy crops, important revisions in management will be needed to maximize their energy yield. Two broad groups of herbaceous plants are seen to have an immediate potential for reducing Puerto Rico's reliance on imported fossil fuels: the tropical grasses (of which sugarcane is the dominant member) and the tropical legumes. Managed for its maximum growth potential, sugarcane is an excellent source of boiler fuel, fermentation substrates, cellulosic feedstocks, and the sweetener sucrose. Other tropical grasses store relatively little extractable sugar while equaling or moderately surpassing sugarcane in yield of cellulosic dry matter. The latter might soon become an economical source of fermentation substrates. Certain legume species are also very effective producers of biomass. Herbaceous tropical legumes are perceived as a potential source of biological nitrogen for energy crops unable to utilize nitrogen from the atmosphere.

Herbaceous land plants as a renewable energy source for Puerto Rico

Energy Technology Data Exchange (ETDEWEB)

Alexander, A G

1980-01-01

Herbaceous tropical plants are a renewable energy source of major importance to many tropical nations. They convert the radiant energy of sunlight to chemical energy, which is stored in plant tissues (cellulose, hemicellulose, lignin) and fermentable solids (sugars, starches). Because all tropical plants do this - even those commonly regarded as weeds - they constitute an inexpensive, renewable, and domestic alternative to foreign fossil energy. The vast majority of herbaceous tropical plants have never been cultivated for food, fiber, or energy. A major screening program would be needed to identify superior species and the most effective roles they can play in a domestic energy industry. Other herbaceous plants, such as sugarcane and tropical forage grasses, have been cultivated for centuries as agricultural commodities. As energy crops, important revisions in management will be needed to maximize their energy yield. Two broad groups of herbaceous plants are seen to have an immediate potential for reducing Puerto Rico's reliance on imported fossil fuels: the tropical grasses (of which sugarcane is the dominant member) and the tropical legumes. Managed for its maximum growth potential, sugarcane is an excellent source of boiler fuel, fermentation substrates, cellulosic feedstocks, and the sweetener sucrose. Other tropical grasses store relatively little extractable sugar while equaling or moderately surpassing sugarcane in yield of cellulosic dry matter. The latter might soon become an economical source of fermentation substrates. Certain legume species are also very effective producers of biomass. Herbaceous tropical legumes are perceived as a potential source of biological nitrogen for energy crops unable to utilize nitrogen from the atmosphere.

Will genomic selection be a practical method for plant breeding?

Science.gov (United States)

Nakaya, Akihiro; Isobe, Sachiko N

2012-11-01

Genomic selection or genome-wide selection (GS) has been highlighted as a new approach for marker-assisted selection (MAS) in recent years. GS is a form of MAS that selects favourable individuals based on genomic estimated breeding values. Previous studies have suggested the utility of GS, especially for capturing small-effect quantitative trait loci, but GS has not become a popular methodology in the field of plant breeding, possibly because there is insufficient information available on GS for practical use. In this review, GS is discussed from a practical breeding viewpoint. Statistical approaches employed in GS are briefly described, before the recent progress in GS studies is surveyed. GS practices in plant breeding are then reviewed before future prospects are discussed. Statistical concepts used in GS are discussed with genetic models and variance decomposition, heritability, breeding value and linear model. Recent progress in GS studies is reviewed with a focus on empirical studies. For the practice of GS in plant breeding, several specific points are discussed including linkage disequilibrium, feature of populations and genotyped markers and breeding scheme. Currently, GS is not perfect, but it is a potent, attractive and valuable approach for plant breeding. This method will be integrated into many practical breeding programmes in the near future with further advances and the maturing of its theory.

Acetylcholinesterase and butyrylcholinesterase inhibitory activity of some selected Nigerian medicinal plants

Directory of Open Access Journals (Sweden)

Taiwo O. Elufioye

Full Text Available Plants have been found to be useful as memory enhansers as well as antiaging. Twenty two of such plants from sixteen families were investigated for their acetylcholinesterase (AChE and butyrylcholinesterase (BuChE inhibitory activities using the in vitro Ellman's spectrophotometric and in situ bioautographic methods with physostigmine as standard. At least three morphological parts were examined for each of the plants investigated and the test concentration was 42.5 µg/ mL. Some plants were active on both enzymes though with some morphological parts being more active than others. The root bark of Spondias mombin showed the highest activity to the two enzymes; 64.77% and 83.94% on AChE and BuChE respectively. Other plant parts of the selected plants exhibited some remarkable selectivity in their actions. Those selectively active against AChE were Alchornia laxiflora stem bark (41.12% and root bark, Callophyllum inophyllurn root bark (56.52%. The leaves of C. jagus (74.25%, Morinda lucida leaves (40.15%, Peltophorum pterocarpum leaves and stem bark (49.5% and 68.85%, respectively, physiostigmine gave 90.31% inhibition. Generally higher activities were found against BuChE. Bombax bromoposenze leaves, root bark and stem bark were particularly active. The inhibition was over 80%. Other selective plant parts are the leaves Antiaris africana, Cissampelos owarensis aerial parts (78.96%, Combretum molle leaves and stem bark (90.42% and 88.13%, respectively, Dioscorea dumentorum root bark and tuber (over 87%, G. kola leaves, Markhamia tomentosa root bark, Pycnanthus angolensis stem bark and Tetrapleura tetraptera leaves. Most of these plants are taken as food or are food ingredients in Nigeria and may account for the low incidence of Alzheimer's disease in the country and may play certain roles in the mediation of the disease.

Simulated geographic variations of plant species richness, evenness and abundance using climatic constraints on plant functional diversity

International Nuclear Information System (INIS)

Kleidon, Axel; Pavlick, Ryan; Reu, Bjoern; Adams, Jonathan

2009-01-01

Among the most pronounced large-scale geographic patterns of plant biodiversity are the increase in plant species richness towards the tropics, a more even distribution of the relative abundances of plant species in the tropics, and a nearly log-normal relative abundance distribution. Here we use an individual-based plant diversity model that relates climatic constraints to feasible plant growth strategies to show that all three basic diversity patterns can be predicted merely from the climatic constraints acting upon plant ecophysiological trade-offs. Our model predicts that towards objectively 'harsher' environments, the range of feasible growth strategies resulting in reproductive plants is reduced, thus resulting in lower functional plant species richness. The reduction of evenness is attributed to a more rapid decline in productivity from the most productive to less productive plant growth strategies since the particular setup of the strategy becomes more important in maintaining high productivity in harsher environments. This approach is also able to reproduce the increase in the deviation from a log-normal distribution towards more evenly distributed communities of the tropics. Our results imply that these general biodiversity relationships can be understood primarily by considering the climatic constraints on plant ecophysiological trade-offs.

Tritium behavior pattern in some soil-plant systems in a tropical environment

International Nuclear Information System (INIS)

Soman, S.D.; Iyengar, T.S.; Sadarangani, S.H.; Vaze, P.K.

1975-01-01

A study of the distribution pattern of tritium in the soil/plant environment gives valuable ecological information on the natural water balance. The results of such a study for the conditions obtaining in India are given in this paper. Field studies are carried out by injection of tritium into some soil/plant systems and following the transfer pathways. The method of extraction for tissue-free-water-tritium (TFWT) is based on the vacuum freeze-drying technique while the tissue-bound-tritium (TBT) is estimated by a modified version of the Shoniger method. The determination of residence time of tritium in aqueous and organic phase in a number of tropical trees has been carried out both for stem-injection as well as intake from the soil. From the results of this study the tree biomass and transpiration rates have been determined. The tritium profile over time, for an acute exposure in certain trees such as Morinda Tinetoria, Achras Sapota etc. shows significantly different patterns compared to the normal pattern shown by Mangifera Indica, Terminalia Catappa, Ficus Glomerata etc. The period of investigation in each case varied from 400 to 1000 h. In most of the cases, the TBT fractions were very low compared to TFWT fractions in the initial stages. The tritium behavior in the tree reflects significant characteristics of the tritium behavior in the soil system. The authors have found that the leaf sampling can be used as an indicator of total environmental tritium behavior. (author)

Fusarium-induced diseases of tropical, perennial crops.

Science.gov (United States)

Ploetz, Randy C

2006-06-01

ABSTRACT The world's oldest ecosystems are found in the tropics. They are diverse, highly evolved, but barely understood. This and subsequent papers describe diseases of tropical, perennial plants that are caused by Fusarium spp. Many of these are economically significant, difficult to manage, and of scientific interest. Some represent coevolved patho-systems (e.g., Panama disease, tracheomycosis of coffee, fusariosis of pineapple, and Fusarium wilt of oil palm), whereas others may be new-encounter diseases or are caused by generalist pathogens (cushion gall of cacao). New vector relationships are evident in other pathosystems (e.g., mango malformation), and two or more pathogens have been shown to cause some of the diseases (Panama disease and tracheomycosis of coffee). More work on these pathosystems is warranted as they could reveal much about the evolution of plant pathogens and the important diseases they cause.

Selection, qualification and training of personnel for nuclear power plants

International Nuclear Information System (INIS)

Anon.

1981-01-01

This standard provides criteria for the selection, qualification and training of personnel for stationary nuclear power plants. Qualifications, responsibilities, and training of personnel in operating and support organizations appropriate for the safe and efficient operation of nuclear power plants are addressed

Isolation and characterization of oxalotrophic bacteria from tropical soils.

Science.gov (United States)

Bravo, Daniel; Braissant, Olivier; Cailleau, Guillaume; Verrecchia, Eric; Junier, Pilar

2015-01-01

The oxalate-carbonate pathway (OCP) is a biogeochemical set of reactions that involves the conversion of atmospheric CO2 fixed by plants into biomass and, after the biological recycling of calcium oxalate by fungi and bacteria, into calcium carbonate in terrestrial environments. Oxalotrophic bacteria are a key element of this process because of their ability to oxidize calcium oxalate. However, the diversity and alternative carbon sources of oxalotrophs participating to this pathway are unknown. Therefore, the aim of this study was to characterize oxalotrophic bacteria in tropical OCP systems from Bolivia, India, and Cameroon. Ninety-five oxalotrophic strains were isolated and identified by sequencing of the 16S rRNA gene. Four genera corresponded to newly reported oxalotrophs (Afipia, Polaromonas, Humihabitans, and Psychrobacillus). Ten strains were selected to perform a more detailed characterization. Kinetic curves and microcalorimetry analyses showed that Variovorax soli C18 has the highest oxalate consumption rate with 0.240 µM h(-1). Moreover, Streptomyces achromogenes A9 displays the highest metabolic plasticity. This study highlights the phylogenetic and physiological diversity of oxalotrophic bacteria in tropical soils under the influence of the oxalate-carbonate pathway.

Diabetes mellitus in Tropical Chronic Pancreatitis Is Not Just a Secondary Type of Diabetes

OpenAIRE

Rossi, L.; Parvin, S.; Hassan, Z.; Hildebrand, P.; Keller, U.; Ali, L.; Beglinger, C.; Azad Khan, A. K.; Whitcomb, David C.; Gyr, N.

2004-01-01

AIMS: In chronic calcific pancreatitis of the tropics, etiology and relationship to developing diabetes mellitus are unknown. Some consider these cases a straightforward secondary type of diabetes, while others suggest selective beta-cell impairment. Testing pancreatic function, we investigated whether selective beta-cell impairment triggers diabetes associated with tropical pancreatitis. METHODS: At a Bangladeshi research institute, 8 chronic tropical pancreatitis and no diabetes mellitus su...

Detection of selected plant viruses by microarrays

OpenAIRE

HRABÁKOVÁ, Lenka

2013-01-01

The main aim of this master thesis was the simultaneous detection of four selected plant viruses ? Apple mosaic virus, Plum pox virus, Prunus necrotic ringspot virus and Prune harf virus, by microarrays. The intermediate step in the process of the detection was optimizing of multiplex polymerase chain reaction (PCR).

Effects of selected multipurpose, medicinal and aromatic plants on in ...

African Journals Online (AJOL)

The study was carried out to evaluate the effects of selected multipurpose, medicinal and aromatic plants on the in vitro methane production and microbial diversity. The plants include multi-purpose trees; Pterocarpus santallinoides, Leucaena leucocephala, Albizia lebbek, Albizia saman, Enterolobium cyclocarpum, ...

Plant phylogeny as a window on the evolution of hyperdiversity in the tropical rainforest biome.

Science.gov (United States)

Eiserhardt, Wolf L; Couvreur, Thomas L P; Baker, William J

2017-06-01

I. II. III. IV. V. VI. VII. VIII. IX. References SUMMARY: Tropical rainforest (TRF) is the most species-rich terrestrial biome on Earth, harbouring just under half of the world's plant species in c. 7% of the land surface. Phylogenetic trees provide important insights into mechanisms underpinning TRF hyperdiversity that are complementary to those obtained from the fossil record. Phylogenetic studies of TRF plant diversity have mainly focused on whether this biome is an evolutionary 'cradle' or 'museum', emphasizing speciation and extinction rates. However, other explanations, such as biome age, immigration and ecological limits, must also be considered. We present a conceptual framework for addressing the drivers of TRF diversity, and review plant studies that have tested them with phylogenetic data. Although surprisingly few in number, these studies point to old age of TRF, low extinction and high speciation rates as credible drivers of TRF hyperdiversity. There is less evidence for immigration and ecological limits, but these cannot be dismissed owing to the limited number of studies. Rapid methodological developments in DNA sequencing, macroevolutionary analysis and the integration of phylogenetics with other disciplines may improve our grasp of TRF hyperdiversity in the future. However, such advances are critically dependent on fundamental systematic research, yielding numerous, additional, well-sampled phylogenies of TRF lineages. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

Temperate and Tropical Plant Collections

DEFF Research Database (Denmark)

Friis, Ib

2015-01-01

The first botanical gardens and collections of preserved plants in the 16th century served didactic purposes and should ensure correct identification of medicinal, ornamental and other useful plants. Collections of preserved plants were nearly all book-herbaria, emulating illustrated books...... and owned by individual botanists. Curiosity cabinets of nobles and prominent scholars were larger collections, in which all kinds of objects of natural history from remote regions could be incorporated. The Linnaean revolution favoured loose-leaf herbaria over the old book-herbaria: herbaria with loose...... sheets could be reorganised in agreement with new knowledge or theories and newly accessed specimens could be placed next to earlier ones of the same species. However, the Linnaean collections reflected the essentialist species concept, according to which all species consisted of individuals with similar...

The Origins of Tropical Rainforest Hyperdiversity.

Science.gov (United States)

Pennington, R Toby; Hughes, Mark; Moonlight, Peter W

2015-11-01

Traditional models for tropical species richness contrast rainforests as "museums" of old species or "cradles" of recent speciation. High plant species diversity in rainforests may be more likely to reflect high episodic evolutionary turnover of species--a scenario implicating high rates of both speciation and extinction through geological time.

Optimizing NSSS power and turbine/generator performance for standardized nuclear power plant designs in tropical climates

International Nuclear Information System (INIS)

Parece, M.V.; Stack, T.G.; Huffman, A.D.

2007-01-01

The EPR was developed by AREVA as a standardized nuclear power plant design that could be deployed throughout the world. The first EPR is currently being constructed at Olkiluoto, Finland. Many of the plant systems for this first-of-a-kind unit are optimized for the climate and heat rejection method (once-through cooling) used at Olkiluoto. Two such systems are the Nuclear Steam Supply System (NSSS) and the Turbine/Generator (T/G) system. To achieve the EPR's target net electrical output for tropical climates and various condenser heat rejection methods, design studies were performed that showed that the NSSS and T/G system designs developed for the Olkiluoto site conditions required modification. The business case for EPR on U.S. sites where average ambient temperature is above 60 F, implies an economical design that provides an average net electrical output of at least 1600 MWe. It has been shown through parametric studies that the key features of the design needed to achieve this goal are: -) rated core thermal power of 4590 MWth, which is supported by plant systems, structures and components; -) the use of mechanical draft cooling towers rather than natural draft cooling towers; -) a low pressure turbine design with reduced exhaust annulus area; and -) a multi-pressure condenser configuration

The effects of the insecticide lambda-Cyhalothrin on the earthworm Eisenia fetida under experimental conditions of tropical and temperate regions

International Nuclear Information System (INIS)

Garcia, Marcos; Scheffczyk, Adam; Garcia, Terezinha; Roembke, Joerg

2011-01-01

Plant Protection Products can affect soil organisms and thus might have negative impacts on soil functions. Little research has been performed on their impact on tropical soils. Therefore, the effects of the insecticide lambda-Cyhalothrin on earthworms were evaluated in acute and chronic laboratory tests modified for tropical conditions, i.e. at selected temperatures (20 and 28 o C) and with two strains (temperate and tropical) of the compost worm Eisenia fetida. The insecticide was spiked in two natural soils, in OECD artificial soil and a newly developed tropical artificial soil. The effects of lambda-Cyhalothrin did rarely vary in the same soil at tropical (LC50: 68.5-229 mg a.i./kg dry weight (DW); EC50: 54.2-60.2 mg a.i./kg DW) and temperate (LC50: 99.8-140 mg a.i./kg DW; EC50: 37.4-44.5 mg a.i./kg DW) temperatures. In tests with tropical soils and high temperature, effect values differed by up to a factor of ten. - Research highlights: → In one soil, effects of lambda-Cyhalothrin did not vary much at two temperatures. → In tropical soils at high temperature, effects differed by up to a factor of ten. → In the tropics, effects of pesticides can be higher or lower as in temperate regions. - The effects of the insecticide lambda-cyhalothrin on earthworms did not differ considerably when performed in the same soil under different temperatures, but LC/EC 50 values varied by a factor of ten between OECD and tropical artificial soil.

The effects of the insecticide lambda-Cyhalothrin on the earthworm Eisenia fetida under experimental conditions of tropical and temperate regions

Energy Technology Data Exchange (ETDEWEB)

Garcia, Marcos [Embrapa Amazonia Ocidental, Rod. AM-10, Km 28, 69.011-970 Manaus, AM (Brazil); Scheffczyk, Adam [ECT Oekotoxikologie, Boettgerstr. 2-14, D-65439 Floersheim (Germany); Garcia, Terezinha [Embrapa Amazonia Ocidental, Rod. AM-10, Km 28, 69.011-970 Manaus, AM (Brazil); Roembke, Joerg, E-mail: j-roembke@ect.d [ECT Oekotoxikologie, Boettgerstr. 2-14, D-65439 Floersheim (Germany)

2011-02-15

Plant Protection Products can affect soil organisms and thus might have negative impacts on soil functions. Little research has been performed on their impact on tropical soils. Therefore, the effects of the insecticide lambda-Cyhalothrin on earthworms were evaluated in acute and chronic laboratory tests modified for tropical conditions, i.e. at selected temperatures (20 and 28 {sup o}C) and with two strains (temperate and tropical) of the compost worm Eisenia fetida. The insecticide was spiked in two natural soils, in OECD artificial soil and a newly developed tropical artificial soil. The effects of lambda-Cyhalothrin did rarely vary in the same soil at tropical (LC50: 68.5-229 mg a.i./kg dry weight (DW); EC50: 54.2-60.2 mg a.i./kg DW) and temperate (LC50: 99.8-140 mg a.i./kg DW; EC50: 37.4-44.5 mg a.i./kg DW) temperatures. In tests with tropical soils and high temperature, effect values differed by up to a factor of ten. - Research highlights: In one soil, effects of lambda-Cyhalothrin did not vary much at two temperatures. In tropical soils at high temperature, effects differed by up to a factor of ten. In the tropics, effects of pesticides can be higher or lower as in temperate regions. - The effects of the insecticide lambda-cyhalothrin on earthworms did not differ considerably when performed in the same soil under different temperatures, but LC/EC{sub 50} values varied by a factor of ten between OECD and tropical artificial soil.

Antiherbivore defenses alter natural selection on plant reproductive traits.

Science.gov (United States)

Thompson, Ken A; Johnson, Marc T J

2016-04-01

While many studies demonstrate that herbivores alter selection on plant reproductive traits, little is known about whether antiherbivore defenses affect selection on these traits. We hypothesized that antiherbivore defenses could alter selection on reproductive traits by altering trait expression through allocation trade-offs, or by altering interactions with mutualists and/or antagonists. To test our hypothesis, we used white clover, Trifolium repens, which has a Mendelian polymorphism for the production of hydrogen cyanide-a potent antiherbivore defense. We conducted a common garden experiment with 185 clonal families of T. repens that included cyanogenic and acyanogenic genotypes. We quantified resistance to herbivores, and selection on six floral traits and phenology via male and female fitness. Cyanogenesis reduced herbivory but did not alter the expression of reproductive traits through allocation trade-offs. However, the presence of cyanogenic defenses altered natural selection on petal morphology and the number of flowers within inflorescences via female fitness. Herbivory influenced selection on flowers and phenology via female fitness independently of cyanogenesis. Our results demonstrate that both herbivory and antiherbivore defenses alter natural selection on plant reproductive traits. We discuss the significance of these results for understanding how antiherbivore defenses interact with herbivores and pollinators to shape floral evolution. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.

Diversity and host range of foliar fungal endophytes: are tropical leaves biodiversity hotspots?

Science.gov (United States)

Arnold, A Elizabeth; Lutzoni, F

2007-03-01

Fungal endophytes are found in asymptomatic photosynthetic tissues of all major lineages of land plants. The ubiquity of these cryptic symbionts is clear, but the scale of their diversity, host range, and geographic distributions are unknown. To explore the putative hyperdiversity of tropical leaf endophytes, we compared endophyte communities along a broad latitudinal gradient from the Canadian arctic to the lowland tropical forest of central Panama. Here, we use molecular sequence data from 1403 endophyte strains to show that endophytes increase in incidence, diversity, and host breadth from arctic to tropical sites. Endophyte communities from higher latitudes are characterized by relatively few species from many different classes of Ascomycota, whereas tropical endophyte assemblages are dominated by a small number of classes with a very large number of endophytic species. The most easily cultivated endophytes from tropical plants have wide host ranges, but communities are dominated by a large number of rare species whose host range is unclear. Even when only the most easily cultured species are considered, leaves of tropical trees represent hotspots of fungal species diversity, containing numerous species not yet recovered from other biomes. The challenge remains to recover and identify those elusive and rarely cultured taxa with narrower host ranges, and to elucidate the ecological roles of these little-known symbionts in tropical forests.

Taxonomic and phylogenetic diversity of vascular plants at Ma'anling volcano urban park in tropical Haikou, China: Reponses to soil properties.

Science.gov (United States)

Cheng, Xia-Lan; Yuan, Lang-Xing; Nizamani, Mir Mohammad; Zhu, Zhi-Xin; Friedman, Cynthia Ross; Wang, Hua-Feng

2018-01-01

Anthropogenic processes and socio-economic factors play important roles in shaping plant diversity in urban parks. To investigate how plant diversity of Ma' anling urban volcano park in Hainan Province, China respond to these factors, we carried out a field investigation on the taxonomic and phylogenetic diversity of vascular plants and soil properties in this area. We found 284 species of vascular plants belonging to 88 families and 241 genera, which included 194 native species, 23 invasive species, 31 naturalized species, 40 cultivars, and 4 rare / endangered plant species. Tree composition and richness significantly varied between different vegetation formations (plantation, secondary forest, and abandoned land). Plant species richness and community composition were significantly affected by elevation (El), soil water content (WC), total soil nitrogen (TN) and soil organic matter (SOM). There were significant diversity differences between plantations and abandoned lands, but not between the plantations and secondary forests. The flora in the study site was tropical in nature, characterized by pantropic distributions. Compared to adjacent areas, floristic composition in the study site was most similar to that of Guangdong, followed by that of Vietnam. Our study revealed the diversity patterns of volcanic plants and provided the basis for future planning of plant conservation, such as preserving plant species, maintaining plant habitats, and coordinating plant management in this region.

Psidium guajava 'Paluma' (the guava plant) as a new bio-indicator of ozone in the tropics

International Nuclear Information System (INIS)

Furlan, C.M.; Moraes, R.M.; Bulbovas, P.; Domingos, M.; Salatino, A.; Sanz, M.J.

2007-01-01

Psidium guajava 'Paluma' saplings were exposed to carbon filtered air (CF), ambient non-filtered air (NF), and ambient non-filtered air + 40 ppb ozone (NF + O 3 ) 8 h per day during two months. The AOT40 values at the end of the experiment were 48, 910 and 12 895 ppb h -1 , respectively for the three treatments. After 5 days of exposure (AOT40 = 1497 ppb h -1 ), interveinal red stippling appeared in plants in the NF + O 3 chamber. In the NF chamber, symptoms were observed only after 40 days of exposure (AOT40 = 880 ppb h -1 ). After 60 days, injured leaves per plant corresponded to 86% in NF + O 3 and 25% in the NF treatment, and the average leaf area injured was 45% in NF + O 3 and 5% in the NF treatment. The extent of leaf area injured (leaf injury index) was explained mainly by the accumulated exposure of ozone (r 2 = 0.91; p < 0.05). - Psidium guajava 'Paluma', a tropical species widely used in Brazilian food industry, is a potential sensitive bio-indicator of ozone

Vasorelaxation induced by common edible tropical plant extracts in isolated rat aorta and mesenteric vascular bed.

Science.gov (United States)

Runnie, I; Salleh, M N; Mohamed, S; Head, R J; Abeywardena, M Y

2004-06-01

In this study, the vasodilatory actions of nine edible tropical plant extracts were investigated. Ipomoea batatas (sweet potato leaf), Piper betle (betel leaf), Anacardium occidentale (cashew leaf), Gynandropsis gynandra (maman leaf), Carica papaya (papaya leaf), and Mentha arvensis (mint leaf) extracts exhibited more than 50% relaxing effect on aortic ring preparations, while Piper betle and Cymbopogon citratus (lemongrass stalk) showed comparable vasorelaxation on isolated perfused mesenteric artery preparation. The vascular effect on the aortic ring preparations were mainly endothelium-dependent, and mediated by nitric oxide (NO) as supported by the inhibition of action in the presence of N(omega)-nitro-L-arginine (NOLA), an nitric oxide synthase (NOS) inhibitor, or by the removal of endothelium. In contrast, vasodilatory actions in resistance vessels (perfused mesenteric vascular beds) appear to involve several biochemical mediators, including NO, prostanoids, and endothelium-dependent hyperpolarizing factors (EDHFs). Total phenolic contents and antioxidant capacities varied among different extracts and found to be independent of vascular relaxation effects. This study demonstrates that many edible plants common in Asian diets to possess potential health benefits, affording protection at the vascular endothelium level.

Chemical interactions between plants in Mediterranean vegetation: the influence of selected plant extracts on Aegilops geniculata metabolome.

Science.gov (United States)

Scognamiglio, Monica; Fiumano, Vittorio; D'Abrosca, Brigida; Esposito, Assunta; Choi, Young Hae; Verpoorte, Robert; Fiorentino, Antonio

2014-10-01

Allelopathy is the chemical mediated communication among plants. While on one hand there is growing interest in the field, on the other hand it is still debated as doubts exist at different levels. A number of compounds have been reported for their ability to influence plant growth, but the existence of this phenomenon in the field has rarely been demonstrated. Furthermore, only few studies have reported the uptake and the effects at molecular level of the allelochemicals. Allelopathy has been reported on some plants of Mediterranean vegetation and could contribute to structuring this ecosystem. Sixteen plants of Mediterranean vegetation have been selected and studied by an NMR-based metabolomics approach. The extracts of these donor plants have been characterized in terms of chemical composition and the effects on a selected receiving plant, Aegilops geniculata, have been studied both at the morphological and at the metabolic level. Most of the plant extracts employed in this study were found to have an activity, which could be correlated with the presence of flavonoids and hydroxycinnamate derivatives. These plant extracts affected the receiving plant in different ways, with different rates of growth inhibition at morphological level. The results of metabolomic analysis of treated plants suggested the induction of oxidative stress in all the receiving plants treated with active donor plant extracts, although differences were observed among the responses. Finally, the uptake and transport into receiving plant leaves of different metabolites present in the extracts added to the culture medium were observed. Copyright © 2014 Elsevier Ltd. All rights reserved.

Key role of symbiotic dinitrogen fixation in tropical forest secondary succession

DEFF Research Database (Denmark)

Batterman, Sarah A.; Hedin, Lars O.; Van Breugel, Michiel

2013-01-01

Forests contribute a significant portion of the land carbon sink, but their ability to sequester CO 2 may be constrained by nitrogen, a major plant-limiting nutrient. Many tropical forests possess tree species capable of fixing atmospheric dinitrogen (N 2), but it is unclear whether this function...... tree species across the entire forest age sequence. These findings show that symbiotic N 2 fixation can have a central role in nitrogen cycling during tropical forest stand development, with potentially important implications for the ability of tropical forests to sequester CO 2....

Thermal performance of different planting substrates and irrigation frequencies in extensive tropical rooftop greeneries

Energy Technology Data Exchange (ETDEWEB)

Lin, Yi-Jiung [Department of Environmental Engineering and Science, Foo-Yin University, Kaohsiung (China); No. 16, Lane 29, Chen-Sing 7th Street, Niao-Song, Kaohsiung 833 (China); Lin, Hsien-Te [Department of Architecture, National Cheng Kung University, Tainan (China); No. 1, Ta-Hsueh Road, Tainan 701 (China)

2011-02-15

The need for the better use of scarce planetary resources has never been more evident than it is today. However, this need is poorly reflected in human housing. In recent years, there has been a growing realization of the importance of constructing human shelters that better conserve energy and water through appropriate insulation and architectural designs. Among the important advancements in these areas is the use of rooftop greeneries for both energy and water conservation. This paper performs an investigation into this topic within the specific climatic context of tropical regions. Long-term experimental results are provided from a four-floor building in Kaohsiung in the southern part of Taiwan. The study involves a fully monitored extensive rooftop greenery and examines four different plant substrates, three different irrigation regimes, and different types of drought-enduring plants to find the most efficient combination of all three in providing maximum heat insulation and water usage efficiency. The attenuation of solar radiation through the vegetation layer is evaluated, as well as the thermal insulation performance of the rooftop greenery structure. Among the substrates, burned sludge has the best thermal reduction percentage of heat amplitude under the roof slab surface (up to 84.4%). Irrigation twice a week has the best thermal reduction percentage of heat amplitude (91.6%). Among the plant types, Sansevieria trifasciata cv. Laurentii Compacta and Rhoeo spathaceo cv. Compacta are found to be suitable for extensive rooftop greeneries because they have the best coverage ratio and are most drought enduring. (author)

Effects of experimental nitrogen additions on plant diversity in tropical forests of contrasting disturbance regimes in southern China

International Nuclear Information System (INIS)

Lu Xiankai; Mo Jiangming; Gilliam, Frank S.; Yu Guirui; Zhang Wei; Fang Yunting; Huang Juan

2011-01-01

Responses of understory plant diversity to nitrogen (N) additions were investigated in reforested forests of contrasting disturbance regimes in southern China from 2003 to 2008: disturbed forest (with harvesting of understory vegetation and litter) and rehabilitated forest (without harvesting). Experimental additions of N were administered as the following treatments: Control, 50 kg N ha -1 yr -1 , and 100 kg N ha -1 yr -1 . Nitrogen additions did not significantly affect understory plant richness, density, and cover in the disturbed forest. Similarly, no significant response was found for canopy closure in this forest. In the rehabilitated forest, species richness and density showed no significant response to N additions; however, understory cover decreased significantly in the N-treated plots, largely a function of a significant increase in canopy closure. Our results suggest that responses of plant diversity to N deposition may vary with different land-use history, and rehabilitated forests may be more sensitive to N deposition. - Highlights: → Nitrogen addition had no significant effect on understory plant diversity in the disturbed forest. → Nitrogen addition significantly decreased understory plant cover. → Nitrogen addition had no effect on richness and density in the rehabilitated forest. → The decrease is largely a function of a significant increase in canopy closure. → Land-use practices may dominate the responses of plant diversity to N addition. - Research in disturbed forests of southeastern China demonstrates that land-use history can substantially alter effects of excess nitrogen deposition on plant diversity of tropical forest ecosystems.

Comparative evaluation of different types of biogas suitable for tropical country

International Nuclear Information System (INIS)

Sahu, S.N.; Gbagbo, J.K.N.; Aneke, F.U.

1997-04-01

The biogas technology - anaerobic digestion - is described together with different types of biogas plants suitable for tropical countries. Cost-benefit analysis of establishing biogas plants, financial support options, and the benefits of using biogas as an energy source in rural areas are presented. (LN)

Vegetation and floristics of a lowland tropical rainforest in northeast Australia.

Science.gov (United States)

Tng, David Y P; Apgaua, Deborah M G; Campbell, Mason J; Cox, Casey J; Crayn, Darren M; Ishida, Françoise Y; Laidlaw, Melinda J; Liddell, Michael J; Seager, Michael; Laurance, Susan G W

2016-01-01

Full floristic data, tree demography, and biomass estimates incorporating non-tree lifeforms are seldom collected and reported for forest plots in the tropics. Established research stations serve as important repositories of such biodiversity and ecological data. With a canopy crane setup within a tropical lowland rainforest estate, the 42-ha Daintree Rainforest Observatory (DRO) in Cape Tribulation, northern Australia is a research facility of international significance. We obtained an estimate of the vascular plant species richness for the site, by surveying all vascular plant species from various mature-phase, remnant and open vegetation patches within the site. We also integrate and report the demography and basal areas of trees ≥ 10 cm diameter at breast height (dbh) in a new 1-ha core plot, an extension to the pre-existing forest 1-ha plot under the canopy crane. In addition, we report for the canopy crane plot new demography and basal areas for smaller-size shrubs and treelets subsampled from nine 20 m(2) quadrats, and liana basal area and abundance from the whole plot. The DRO site has an estimated total vascular plant species richness of 441 species, of which 172 species (39%) are endemic to Australia, and 4 species are endemics to the Daintree region. The 2 x 1-ha plots contains a total of 262 vascular plant species of which 116 (1531 individuals) are tree species ≥ 10 cm dbh. We estimate a stem basal area of 34.9 m(2) ha(-1), of which small stems (tree saplings and shrubs analysis shows that DRO forests has a comparatively high stem density and moderate species diversity, due to the influence of cyclones. These data will provide an important foundation for ecological and conservation studies in lowland tropical forest. We present a floristic checklist, a lifeform breakdown, and demography data from two 1-ha rainforest plots from a lowland tropical rainforest study site. We also present a meta-analysis of stem densities and species diversity from

Herbivores modify selection on plant functional traits in a temperate rainforest understory.

Science.gov (United States)

Salgado-Luarte, Cristian; Gianoli, Ernesto

2012-08-01

There is limited evidence regarding the adaptive value of plant functional traits in contrasting light environments. It has been suggested that changes in these traits in response to light availability can increase herbivore susceptibility. We tested the adaptive value of plant functional traits linked with carbon gain in contrasting light environments and also evaluated whether herbivores can modify selection on these traits in each light environment. In a temperate rainforest, we examined phenotypic selection on functional traits in seedlings of the pioneer tree Aristotelia chilensis growing in sun (canopy gap) and shade (forest understory) and subjected to either natural herbivory or herbivore exclusion. We found differential selection on functional traits depending on light environment. In sun, there was positive directional selection on photosynthetic rate and relative growth rate (RGR), indicating that selection favors competitive ability in a high-resource environment. Seedlings with high specific leaf area (SLA) and intermediate RGR were selected in shade, suggesting that light capture and conservative resource use are favored in the understory. Herbivores reduced the strength of positive directional selection acting on SLA in shade. We provide the first demonstration that natural herbivory rates can change the strength of selection on plant ecophysiological traits, that is, attributes whose main function is resource uptake. Research addressing the evolution of shade tolerance should incorporate the selective role of herbivores.

Cesium and strontium sorption by selected tropical and subtropical soils around nuclear facilities

International Nuclear Information System (INIS)

Chiang, P.N.; Wang, M. K.; Huang, P.M.; Wang, J.J.; Chiu, C.Y.

2010-01-01

The dynamics of Cs and Sr sorption by soils, especially in the subtropics and tropics, as influenced by soil components are not fully understood. The rates and capacities of Cs and Sr sorption by selected subtropical and tropical soils in Taiwan were investigated to facilitate our understanding of the transformation and dynamics of Cs and Sr in soils developed under highly weathering intensity. The Langmuir isotherms and kinetic rates of Cs and Sr sorption on the Ap1 and Bt1 horizons of the Long-Tan (Lt) and the A and Bt1 horizons of the Kuan-Shan (Kt), Mao-Lin (Tml) and Chi-Lo (Cl) soils were selected for this study. Air-dried soil ( -5 to 1.88 x 10 -3 M of CsCl (pH 4.0) or 1.14 x 10 -4 to 2.85 x 10 -3 M of SrCl 2 (pH 4.0) solutions at 25 deg. C. The sorption maximum capacity (q m ) of Cs by the Ap1 and Bt1 horizons of the Lt soil (62.24 and 70.70 mmol Cs kg -1 soil) were significantly (p -1 soil in Kt soil and 34.83 and 29.96 mmol Cs kg -1 soil in Cl soil, respectively), however, the sorption maximum capacity values of the Lt and Tml soils did not show significant differences. The amounts of pyrophosphate extractable Fe (Fe p ) were correlated significantly with the Cs and Sr sorption capacities (for Cs sorption, r 2 = 0.97, p -4 ; for Sr sorption, r 2 = 0.82, p -3 ). The partition coefficient of radiocesium sorbed on soil showed the following order: Cl soil >> Kt soil > Tml soil > Lt soil. It was due to clay minerals. The second-order kinetic model was applied to the Cs and Sr sorption data. The rate constant of Cs or Sr sorption on the four soils was substantiality increased with increasing temperature. This is attributable to the availability of more energy for bond breaking and bond formation brought about by the higher temperatures. The rate constant of Cs sorption at 308 K was 1.39-2.09 times higher than that at 278 K in the four soils. The activation energy of Cs and Sr sorbed by the four soils ranged from 7.2 to 16.7 kJ mol -1 and from 15.2 to 22.4 kJ mol

Antimalarial evaluation of selected medicinal plant extracts used in Iranian traditional medicine

Directory of Open Access Journals (Sweden)

Mohammad Hossein Feiz Haddad

2017-04-01

Full Text Available Objective(s: In an attempt to discover new natural active extracts against malaria parasites, the present study evaluated the antiplasmodial properties of selected plants based on Iranian traditional medicine. Materials and Methods: Ten plant species found in Iran were selected and collected based on the available literature about the Iranian traditional medicine. The methanolic extracts of these plants were investigated for in vitro antimalarial properties against chloroquine-sensitive (3D7 and multi-drug resistant (K1 strains of Plasmodium falciparum. Their in vivo activity against Plasmodium berghei infection in mice was also determined. Cytotoxicity tests were carried out using the Raji cells line using the MTT assay. The extracts were phytochemically screened for their active constituents. Results: According to the IC50 and selectivity index (SI values, of the 10 selected plant species, Citrullus colocynthis, Physalis alkekengi, and Solanum nigrum displayed potent in vitro antimalarial activity against both 3D7 and K1 strains with no toxicity (IC50= 2.01-18.67 µg/ml and SI=3.55 to 19.25.  Comparisons between treated and untreated control mice showed that the mentioned plant species reduced parasitemia by 65.08%, 57.97%, and 60.68%, respectively.  The existence of antiplasmodial compounds was detected in these plant extracts. Conclusion: This was the first study to highlight the in vitro and in vivo antiplasmodial effects of             C. colocynthis, P. alkekengi, and S. nigrum in Iran. Future studies can use these findings to design further biological tests to identify the active constituents of the mentioned plant species and clarify their mechanism of action.

Will genomic selection be a practical method for plant breeding?

OpenAIRE

Nakaya, Akihiro; Isobe, Sachiko N.

2012-01-01

Background Genomic selection or genome-wide selection (GS) has been highlighted as a new approach for marker-assisted selection (MAS) in recent years. GS is a form of MAS that selects favourable individuals based on genomic estimated breeding values. Previous studies have suggested the utility of GS, especially for capturing small-effect quantitative trait loci, but GS has not become a popular methodology in the field of plant breeding, possibly because there is insufficient information avail...

The future of tropical forests.

Science.gov (United States)

Wright, S Joseph

2010-05-01

Five anthropogenic drivers--land use change, wood extraction, hunting, atmospheric change, climate change--will largely determine the future of tropical forests. The geographic scope and intensity of these five drivers are in flux. Contemporary land use change includes deforestation (approximately 64,000 km(2) yr(-1) for the entire tropical forest biome) and natural forests regenerating on abandoned land (approximately 21,500 km(2) yr(-1) with just 29% of the biome evaluated). Commercial logging is shifting rapidly from Southeast Asia to Africa and South America, but local fuelwood consumption continues to constitute 71% of all wood production. Pantropical rates of net deforestation are declining even as secondary and logged forests increasingly replace old-growth forests. Hunters reduce frugivore, granivore and browser abundances in most forests. This alters seed dispersal, seed and seedling survival, and hence the species composition and spatial template of plant regeneration. Tropical governments have responded to these local threats by protecting 7% of all land for the strict conservation of nature--a commitment that is only matched poleward of 40 degrees S and 70 degrees N. Protected status often fails to stop hunters and is impotent against atmospheric and climate change. There are increasing reports of stark changes in the structure and dynamics of protected tropical forests. Four broad classes of mechanisms might contribute to these changes. Predictions are developed to distinguish among these mechanisms.

Selected bibliography of agroforestry

Energy Technology Data Exchange (ETDEWEB)

Majisu, L.; Labelle, R.

1982-01-01

A successor to a preliminary bibliography by Teemba, L. and containing some of the same references. References (1953-1982) were selected from the 3000 reprints in the agroforestry collection in the ICRAF library, and from approximately 1500 monographs, reports etc. They are grouped in 7 main sections: Agroforestry general, including subsections on agroforestry in arid and semi-arid lands, in lowlands - humid tropics, and in highlands; Agroforestry land-use systems, including concepts from agriculture and forestry land-use systems, and agroforestry systems (cropping with trees, silvopastoral and agrosilvopastoral systems); Plants and plant management, including multipurpose trees and shrubs; Physical and ecological aspects, (desertification and deforestation, agricultural meteorology, soils and soil management); social and economic aspects, including rural development and human ecology; Training and education; and Information sources and management. A list of information centres relevant to agroforestry is given, and there are subject, species and geographical indexes. 437 references

Declines of seagrasses in a tropical harbour, North Queensland ...

Indian Academy of Sciences (India)

2015-04-17

Apr 17, 2015 ... Centre for Tropical Water and Aquatic Ecosystem Research, James Cook University, Queensland, ... marily in the grey literature sponsored by the fishing indus- ..... age treatment plants were upgraded and urban and agri-.

Tropical rainforest response to marine sky brightening climate engineering

Science.gov (United States)

Muri, Helene; Niemeier, Ulrike; Kristjánsson, Jón Egill

2015-04-01

Tropical forests represent a major atmospheric carbon dioxide sink. Here the gross primary productivity (GPP) response of tropical rainforests to climate engineering via marine sky brightening under a future scenario is investigated in three Earth system models. The model response is diverse, and in two of the three models, the tropical GPP shows a decrease from the marine sky brightening climate engineering. Partial correlation analysis indicates precipitation to be important in one of those models, while precipitation and temperature are limiting factors in the other. One model experiences a reversal of its Amazon dieback under marine sky brightening. There, the strongest partial correlation of GPP is to temperature and incoming solar radiation at the surface. Carbon fertilization provides a higher future tropical rainforest GPP overall, both with and without climate engineering. Salt damage to plants and soils could be an important aspect of marine sky brightening.

Selection of sites for nuclear power plants in The Netherlands. Pt. A

International Nuclear Information System (INIS)

1985-01-01

In this report a policy proposal is presented concerning the selection of location sites for new nuclear power plants in the Netherlands. Firstly it is investigated which of the 29 already selected location sites are not to be taken into further account because of obvious obstructions (close vicinity of a big city etc.). The remaining sites are judged on the base of local population magnitude. The sites that pass the last criteria are relatively compared from a large number of viewpoints. To round off the selection procedure the government will explain why they consider the finally selected sites to be suitable for location of new nuclear power plants. Steps are indicated to prevent the decrease of planologic suitability of the selected location sites. (Auth.)

Digest: Plants adapt under attack: genotypic selection and phenotypic plasticity under herbivore pressure.

Science.gov (United States)

Hawkins, Nichola J

2018-03-31

Plant species adapt to changing environmental conditions through phenotypic plasticity and natural selection. Agrawal et al. (2018) found that dandelions responded to the presence of insect pests by producing higher levels of defensive compounds. This defensive response resulted both from phenotypic plasticity, with individual plants' defenses triggered by insect attack, and from evolution by natural selection acting on genetic variation in the plant population. © 2018 The Author(s). Evolution © 2018 The Society for the Study of Evolution.

Tropical savannas and dry forests.

Science.gov (United States)

Pennington, R Toby; Lehmann, Caroline E R; Rowland, Lucy M

2018-05-07

In the tropics, research, conservation and public attention focus on rain forests, but this neglects that half of the global tropics have a seasonally dry climate. These regions are home to dry forests and savannas (Figures 1 and 2), and are the focus of this Primer. The attention given to rain forests is understandable. Their high species diversity, sheer stature and luxuriance thrill biologists today as much as they did the first explorers in the Age of Discovery. Although dry forest and savanna may make less of a first impression, they support a fascinating diversity of plant strategies to cope with stress and disturbance including fire, drought and herbivory. Savannas played a fundamental role in human evolution, and across Africa and India they support iconic megafauna. Copyright © 2018 Elsevier Ltd. All rights reserved.

EFFECT OF COVER CROPS ON SOIL ATTRIBUTES, PLANT NUTRITION, AND IRRIGATED TROPICAL RICE YIELD

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ANDRE FROES DE BORJA REIS

2017-01-01

Full Text Available In flood plains, cover crops are able to alter soil properties and significantly affect rice nutrition and yield. The aims of this study were to determine soil properties, plant nutrition, and yield of tropical rice cultivated on flood plains after cover crop cultivation with conventional tillage (CT and no-tillage system (NTS at low and high nitrogen (N fertilization levels. The experimental design was a randomized block in a split-split-plot scheme with four replications. In the main plots were cover crops sunhemp (Crotalaria juncea and C. spectabilis, velvet bean (Mucuna aterrima, jackbean (Canavalia ensiformis, pigeon pea (Cajanus cajan, Japanese radish (Raphanus sativus, cowpea (Vigna unguiculata and a fallow field. In the subplots were the tillage systems (CT or NTS. The nitrogen fertilization levels in the sub-subplots were (10 kg N ha-1 and 45 kg N ha-1. All cover crops except Japanese radish significantly increased mineral soil nitrogen and nitrate concentrations. Sunhemp, velvet bean, and cowpea significantly increased soil ammonium content. The NTS provides higher mineral nitrogen and ammonium content than that by CT. Overall, cover crops provided higher levels of nutrients to rice plants in NTS than in CT. Cover crops provide greater yield than fallow treatments. Rice yield was higher in NTS than in CT, and greater at a higher rather than lower nitrogen fertilization level.

Sensitivity of tropical carbon to climate change constrained by carbon dioxide variability.

Science.gov (United States)

Cox, Peter M; Pearson, David; Booth, Ben B; Friedlingstein, Pierre; Huntingford, Chris; Jones, Chris D; Luke, Catherine M

2013-02-21

The release of carbon from tropical forests may exacerbate future climate change, but the magnitude of the effect in climate models remains uncertain. Coupled climate-carbon-cycle models generally agree that carbon storage on land will increase as a result of the simultaneous enhancement of plant photosynthesis and water use efficiency under higher atmospheric CO(2) concentrations, but will decrease owing to higher soil and plant respiration rates associated with warming temperatures. At present, the balance between these effects varies markedly among coupled climate-carbon-cycle models, leading to a range of 330 gigatonnes in the projected change in the amount of carbon stored on tropical land by 2100. Explanations for this large uncertainty include differences in the predicted change in rainfall in Amazonia and variations in the responses of alternative vegetation models to warming. Here we identify an emergent linear relationship, across an ensemble of models, between the sensitivity of tropical land carbon storage to warming and the sensitivity of the annual growth rate of atmospheric CO(2) to tropical temperature anomalies. Combined with contemporary observations of atmospheric CO(2) concentration and tropical temperature, this relationship provides a tight constraint on the sensitivity of tropical land carbon to climate change. We estimate that over tropical land from latitude 30° north to 30° south, warming alone will release 53 ± 17 gigatonnes of carbon per kelvin. Compared with the unconstrained ensemble of climate-carbon-cycle projections, this indicates a much lower risk of Amazon forest dieback under CO(2)-induced climate change if CO(2) fertilization effects are as large as suggested by current models. Our study, however, also implies greater certainty that carbon will be lost from tropical land if warming arises from reductions in aerosols or increases in other greenhouse gases.

Potential Study of Water Extraction from Selected Plants

Directory of Open Access Journals (Sweden)

Musa S.

2017-01-01

Full Text Available Water is absorbed by the roots of a plant and transported subsequently as a liquid to all parts of the plant before being released into the atmosphere as transpiration. In this study, seven(7selected plant species collected from urban, rural and forested areas were studied and characterized. The water was collected using transparent plastic bag that being tied to the tree branches. Then, the vapouris water trapped inside the plastic bag and through the condensation process, it become water droplets. Water quality parameters such as temperature, pH value, DO, turbidity, colour, magnesium, calcium, nitrate and chloride were analyzed. The analysis was compared to drinking water quality standard set by the Ministry of Health Malaysia. Based on the results, it shows that banana leaf has a higher rate of water extraction compared to others. Thus, the plant can be categorised as a helpful guide for emergency use of water or as an alternative source to survival.

Importance of adaptation and genotype × environment interactions in tropical beef breeding systems.

Science.gov (United States)

Burrow, H M

2012-05-01

This paper examines the relative importance of productive and adaptive traits in beef breeding systems based on Bos taurus and tropically adapted breeds across temperate and (sub)tropical environments. In the (sub)tropics, differences that exist between breeds in temperate environments are masked by the effects of environmental stressors. Hence in tropical environments, breeds are best categorised into breed types to compare their performance across environments. Because of the presence of environmental stressors, there are more sources of genetic variation in tropical breeding programmes. It is therefore necessary to examine the genetic basis of productive and adaptive traits for breeding programmes in those environments. This paper reviews the heritabilities and genetic relationships between economically important productive and adaptive traits relevant to (sub)tropical breeding programmes. It is concluded that it is possible to simultaneously genetically improve productive and adaptive traits in tropically adapted breeds of beef cattle grazed in tropical environments without serious detrimental consequences for either adaptation or production. However, breed-specific parameters are required for genetic evaluations. The paper also reviews the magnitude of genotype × environment (G × E) interactions impacting on production and adaptation of cattle, where 'genotype' is defined as breed (within a crossbreeding system), sire within breed (in a within-breed selection programme) or associations between economically important traits and single nucleotide polymorphisms (SNPs - within a marker-assisted selection programme). It is concluded that re-ranking of breeds across environments is best managed by the use of the breed type(s) best suited to the particular production environment. Re-ranking of sires across environments is apparent in poorly adapted breed types across extreme tropical and temperate environments or where breeding animals are selected in a temperate

Regulatory requirements for nuclear power plant site selection in Malaysia-a review.

Science.gov (United States)

Basri, N A; Hashim, S; Ramli, A T; Bradley, D A; Hamzah, K

2016-12-01

Malaysia has initiated a range of pre-project activities in preparation for its planned nuclear power programme. Clearly one of the first steps is the selection of sites that are deemed suitable for the construction and operation of a nuclear power plant. Here we outline the Malaysian regulatory requirements for nuclear power plant site selection, emphasizing details of the selection procedures and site characteristics needed, with a clear focus on radiation safety and radiation protection in respect of the site surroundings. The Malaysia Atomic Energy Licensing Board (AELB) site selection guidelines are in accord with those provided in International Atomic Energy Agency (IAEA) and United Stated Nuclear Regulatory Commission (USNRC) documents. To enhance the suitability criteria during selection, as well as to assist in the final decision making process, possible assessments using the site selection characteristics and information are proposed.

Analysis of chemical constituents in medicinal plants of selected ...

African Journals Online (AJOL)

Analysis of chemical constituents in medicinal plants of selected districts of Pakhtoonkhwa, Pakistan. I Hussain, R Ullah, J Khan, N Khan, M Zahoor, N Ullah, MuR Khattak, FA Khan, A Baseer, M Khurram ...

Antioxidant activities of the selected plants from the family ...

African Journals Online (AJOL)

USER

2010-02-15

Feb 15, 2010 ... Extraction of nine plants selected from the family Euphorbiaceae, Lauraceae, Malvaceae and. Balsaminaceae ... Total phenolic contents were determined with Folin- ... levels of antioxidant activity in vitro may be of value in the.

Assessment parameters for coal-fired generation plant site selection

OpenAIRE

Abbas, Ahmad Rosly; Low, K. S.; Ahmad, Ir. Mohd Noh; Chan, J. H.; Sasekumar, A.; Abdul Ghaffar, Fauza; Osman Salleh, Khairulmaini; Raj, John K.; Abdul Yamin, Saad; Wan Aida, Wan Zahari; Phua, Y. T.; Phua, Y. N.; Wong, Y. Y.; Jamaludin, Ir. Mashitah; Jaafar, Shaari

2005-01-01

In order to meet future demand for electricity, Tenaga Nasional Berhad (TNB) is committedto the long-term strategic planning in locating suitable sites for future development of power stations.Site selection is an important process in the early planning stage of any power plant development asit will have significant implications on the capital investment, operational as well as the environmentand socio-economic costs of the power plant.The aim of this presentation is to briefly describe the t...

Phylogenetic and Functional Diversity of Fleshy-Fruited Plants Are Positively Associated with Seedling Diversity in a Tropical Montane Forest

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Marcia C. Muñoz

2017-08-01

Full Text Available Mutualistic interactions between plants and animals can affect both plant and animal communities, and potentially leave imprints on plant demography. Yet, no study has simultaneously tested how trait variation in plant resources shapes the diversity of animal consumers, and how these interactions influence seedling recruitment. Here, we analyzed whether (i phylogenetic diversity and functional diversity of fruiting plants were correlated with the corresponding diversity of frugivorous birds, and (ii whether phylogenetic diversity and functional identity of plant and bird communities influenced the corresponding diversity and identity of seedling communities. We recorded mutualistic interactions between fleshy-fruited plants and frugivorous birds and seedling communities in 10 plots along an elevational gradient in the Colombian Andes. We built a phylogeny for plants/seedlings and birds and measured relevant morphological plant and bird traits that influence plant-bird interactions and seedling recruitment. We found that phylogenetic diversity and functional diversity of frugivorous birds were positively associated with the corresponding diversities of fruiting plants, consistent with a bottom-up effect of plants on birds. Moreover, the phylogenetic diversity of seedlings was related to the phylogenetic diversity of plants, but was unrelated to the phylogenetic diversity of frugivorous birds, suggesting that top-down effects of animals on seedlings were weak. Mean seed mass of seedling communities was positively associated with the mean fruit mass of plants, but was not associated with the mean avian body mass in the frugivore communities. Our study shows that variation in the traits of fleshy-fruited plants was associated with the diversity of frugivorous birds and affected the future trajectory of seedling recruitment, whereas the morphological traits of animal seed dispersers were unrelated to the phylogenetic and functional structure of

Identifying and Selecting Plants for the Landscape. Volume 23, Number 5.

Science.gov (United States)

Rodekohr, Sherie; Harris, Clark Richard

This handbook on identifying and selecting landscape plants can be used as a reference in landscaping courses or on an individual basis. The first of two sections, Identifying Plants for the Landscape, contains the following tables: shade tree identification; flowering tree identification; evergreen tree identification; flowering shrub…

Urgent need for warming experiments in tropical forests

Science.gov (United States)

Calaveri, Molly A.; Reed, Sasha C.; Smith, W. Kolby; Wood, Tana E.

2015-01-01

Although tropical forests account for only a fraction of the planet's terrestrial surface, they exchange more carbon dioxide with the atmosphere than any other biome on Earth, and thus play a disproportionate role in the global climate. In the next 20 years, the tropics will experience unprecedented warming, yet there is exceedingly high uncertainty about their potential responses to this imminent climatic change. Here, we prioritize research approaches given both funding and logistical constraints in order to resolve major uncertainties about how tropical forests function and also to improve predictive capacity of earth system models. We investigate overall model uncertainty of tropical latitudes and explore the scientific benefits and inevitable trade-offs inherent in large-scale manipulative field experiments. With a Coupled Model Intercomparison Project Phase 5 analysis, we found that model variability in projected net ecosystem production was nearly 3 times greater in the tropics than for any other latitude. Through a review of the most current literature, we concluded that manipulative warming experiments are vital to accurately predict future tropical forest carbon balance, and we further recommend the establishment of a network of comparable studies spanning gradients of precipitation, edaphic qualities, plant types, and/or land use change. We provide arguments for long-term, single-factor warming experiments that incorporate warming of the most biogeochemically active ecosystem components (i.e. leaves, roots, soil microbes). Hypothesis testing of underlying mechanisms should be a priority, along with improving model parameterization and constraints. No single tropical forest is representative of all tropical forests; therefore logistical feasibility should be the most important consideration for locating large-scale manipulative experiments. Above all, we advocate for multi-faceted research programs, and we offer arguments for what we consider the most

An ecosystem model for tropical forest disturbance and selective logging

Science.gov (United States)

Maoyi Huang; Gregory P. Asner; Michael Keller; Joseph A. Berry

2008-01-01

[1] A new three-dimensional version of the Carnegie-Ames-Stanford Approach (CASA) ecosystem model (CASA-3D) was developed to simulate regional carbon cycling in tropical forest ecosystems after disturbances such as logging. CASA-3D has the following new features: (1) an alternative approach for calculating absorbed photosynthetically active radiation (APAR) using new...

Selective absorption pilot plant for decontamination of fuel reprocessing plant off-gas

Energy Technology Data Exchange (ETDEWEB)

Stephenson, M.J.; Eby, R.S.; Huffstetler, V.C.

1977-10-01

A fluorocarbon-based selective absorption process for removing krypton-85, carbon-14, and radon-222 from the off-gas of conventional light water and advanced reactor fuel reprocessing plants is being developed at the Oak Ridge Gaseous Diffusion Plant in conjunction with fuel recycle work at the Oak Ridge National Laboratory and at the Savannah River Laboratory. The process is characterized by an especially high tolerance for many other reprocessing plant off-gas components. This report presents detailed drawings and descriptions of the second generation development pilot plant as it has evolved after three years of operation. The test facility is designed on the basis of removing 99% of the feed gas krypton and 99.9% of the carbon and radon, and can handle a nominal 15 scfm (425 slm) of contaminated gas at pressures from 100 to 600 psig (7.0 to 42.2 kg/cm/sup 2/) and temperatures from minus 45 to plus 25/sup 0/F (-43 to -4/sup 0/C). Part of the development program is devoted to identifying flowsheet options and simplifications that lead to an even more economical and reliable process. Two of these applicative flowsheets are discussed.

In vitro propagation of tropical hardwood tree species — A review (2001-2011)

Science.gov (United States)

Paula M. Pijut; Rochelle R. Beasley; Shaneka S. Lawson; Kaitlin J. Palla; Micah E. Stevens; Ying. Wang

2012-01-01

Tropical hardwood tree species are important economically and ecologically, and play a significant role in the biodiversity of plant and animal species within an ecosystem. There are over 600 species of tropical timbers in the world, many of which are commercially valuable in the international trade of plywood, roundwood, sawnwood, and veneer. Many of these tree...

Emissions of biogenic volatile organic compounds and subsequent photochemical production of secondary organic aerosol in mesocosm studies of temperate and tropical plant species

Science.gov (United States)

Wyche, K. P.; Ryan, A. C.; Hewitt, C. N.; Alfarra, M. R.; McFiggans, G.; Carr, T.; Monks, P. S.; Smallbone, K. L.; Capes, G.; Hamilton, J. F.; Pugh, T. A. M.; MacKenzie, A. R.

2014-12-01

Silver birch (Betula pendula) and three Southeast Asian tropical plant species (Ficus cyathistipula, Ficus benjamina and Caryota millis) from the pantropical fig and palm genera were grown in a purpose-built and environment-controlled whole-tree chamber. The volatile organic compounds emitted from these trees were characterised and fed into a linked photochemical reaction chamber where they underwent photo-oxidation under a range of controlled conditions (relative humidity or RH ~65-89%, volatile organic compound-to-NOx or VOC / NOx ~3-9 and NOx ~2 ppbV). Both the gas phase and the aerosol phase of the reaction chamber were monitored in detail using a comprehensive suite of on-line and off-line chemical and physical measurement techniques. Silver birch was found to be a high monoterpene and sesquiterpene but low isoprene emitter, and its emissions were observed to produce measurable amounts of secondary organic aerosol (SOA) via both nucleation and condensation onto pre-existing seed aerosol (YSOA 26-39%). In contrast, all three tropical species were found to be high isoprene emitters with trace emissions of monoterpenes and sesquiterpenes. In tropical plant experiments without seed aerosol there was no measurable SOA nucleation, but aerosol mass was shown to increase when seed aerosol was present. Although principally isoprene emitting, the aerosol mass produced from tropical fig was mostly consistent (i.e. in 78 out of 120 aerosol mass calculations using plausible parameter sets of various precursor specific yields) with condensation of photo-oxidation products of the minor volatile organic compounds (VOCs) co-emitted; no significant aerosol yield from condensation of isoprene oxidation products was required in the interpretations of the experimental results. This finding is in line with previous reports of organic aerosol loadings consistent with production from minor biogenic VOCs co-emitted with isoprene in principally isoprene-emitting landscapes in Southeast

Plant protein and secondary metabolites influence diet selection in a mammalian specialist herbivore

Science.gov (United States)

Amy C. Ulappa; Rick G. Kelsey; Graham G. Frye; Janet L. Rachlow; LIsa A. Shipley; Laura Bond; Xinzhu Pu; Jennifer Sorensen. Forbey

2014-01-01

For herbivores, nutrient intake is limited by the relatively low nutritional quality of plants and high concentrations of potentially toxic defensive compounds (plant secondary metabolites [PSMs]) produced by many plants. In response to phytochemical challenges, some herbivores selectively forage on plants with higher nutrient and lower PSM concentrations relative to...

Five thousand years of tropical lake sediment DNA records from Benin

Science.gov (United States)

Bremond, L.; Favier, C.; Ficetola, G. F.; Tossou, M. G.; Akouégninou, A.; Gielly, L.; Giguet-Covex, C.; Oslisly, R.; Salzmann, U.

2017-08-01

Until now, sedimentary DNA (sedDNA) studies have only focused on cold and temperate regions were DNA is relatively well preserved. Consequently, the tropics, where vegetation is hyperdiverse and natural archives are rare, have been neglected and deserve attention. In this study, we used next-generation sequencing to barcode sedDNA from Lake Sele, localized in the tropical lowlands of Benin (Africa), and compared the taxonomic diversity detected by DNA analyses with pollen assemblages. Plant sedDNA was successfully amplified from 33 of the 34 successfully extracted samples. In total, 43 taxa were identified along the 5000 years spanned by the sediment: 22 taxa were identified at the family level and 21 at the genus level. The plant diversity recovered through sedDNA from Lake Sele showed a specific local signal and limited overlapping with pollen. Introduced plants, grown and cultivated close to the water, such as sweet potato, were also well recorded by sedDNA. It appears, therefore, to be a promising approach to studying past diversity in tropical regions, and could help in tracking the introduction and history of agriculture. This is the first time this method has been used in the field of domestication and dissemination of several specific crops, and the results are very encouraging.

Which statistics should tropical biologists learn?

Science.gov (United States)

Loaiza Velásquez, Natalia; González Lutz, María Isabel; Monge-Nájera, Julián

2011-09-01

Tropical biologists study the richest and most endangered biodiversity in the planet, and in these times of climate change and mega-extinctions, the need for efficient, good quality research is more pressing than in the past. However, the statistical component in research published by tropical authors sometimes suffers from poor quality in data collection; mediocre or bad experimental design and a rigid and outdated view of data analysis. To suggest improvements in their statistical education, we listed all the statistical tests and other quantitative analyses used in two leading tropical journals, the Revista de Biología Tropical and Biotropica, during a year. The 12 most frequent tests in the articles were: Analysis of Variance (ANOVA), Chi-Square Test, Student's T Test, Linear Regression, Pearson's Correlation Coefficient, Mann-Whitney U Test, Kruskal-Wallis Test, Shannon's Diversity Index, Tukey's Test, Cluster Analysis, Spearman's Rank Correlation Test and Principal Component Analysis. We conclude that statistical education for tropical biologists must abandon the old syllabus based on the mathematical side of statistics and concentrate on the correct selection of these and other procedures and tests, on their biological interpretation and on the use of reliable and friendly freeware. We think that their time will be better spent understanding and protecting tropical ecosystems than trying to learn the mathematical foundations of statistics: in most cases, a well designed one-semester course should be enough for their basic requirements.

INTAKE OF TROPICAL TANNINIFEROUS PLANTS BY GOATS AND SHEEP WHEN OFFERED AS A SOLE FEED

Directory of Open Access Journals (Sweden)

Miguel A. Alonso-Díaz

2009-06-01

Full Text Available The intake of tropical tanniniferous plants (TTP (Lysiloma latisiliquum, Piscidia piscipula and Acacia pennatula when offered as a single feed to small ruminants could help to design a supplementation strategy looking for an anthelmintic effect. The objectives of the current study were: i to determine the chemical composition of TTP offered to goats and sheep, ii to determine and compare the total intake of TTP when offered as a single feed to goats and sheep. Adult sheep and goats, with experience in the intake of TTP, were allocated to individual pens. Three consecutive experimental period (15 d separated by seven days were used. Each period consisted of 10 d adaptation and 5 days of experiment. During adaptation animals received 40 g of leaves of each TTP plant, fresh grass and concentrate feed on a daily basis. During the experimental period animals were fed ad libitum only with the fodder of a sole TTP. Between each period, animals were fed with fresh grass (ad libitum and concentrate (200 g-1 day. Crude protein (CP, neutral detergent fiber (NDF, acid detergent fiber (ADF and lignin (L were determined from each TTP. Total polyphenols (TP, total tannins (TT and condensed tannins (CT were also determined. During each experimental period, refused fodder and intake were measured every 24 h. A multivariate analysis was used in order to determine the effect of factors (animal species, plant species and individual animal within specie on the dry matter intake. Factors with statistical effect (P

Does the edge effect influence plant community structure in a tropical dry forest? O efeito de borda influencia a estrutura da comunidade vegetal em uma floresta tropical seca?

Directory of Open Access Journals (Sweden)

Diogo Gallo Oliveira

2013-04-01

Full Text Available Edge effects are considered a key factor in regulating the structure of plant communities in different ecosystems. However, regardless to few studies, edge influence does not seem to be decisive in semiarid regions such as the Brazilian tropical dry forest known as Caatinga but this issue remains inconclusive. The present study tests the null hypothesis that the plant community of shrubs and trees does not change in its structure due to edge effects. Twenty-four plots (20 x 20 m were set up in a fragment of Caatinga, in which 12 plots were in the forest edges and 12 plots were inside the fragment. Tree richness, abundance and species composition did not differ between edge and interior plots. The results of this study are in agreement with the pattern previously found for semiarid environments and contrasts with previous results obtained in different environments such as Rainforests, Savanna and Forest of Araucaria, which indicate abrupt differences between the border and interior of the plant communities in these ecosystems, and suggest that the community of woody plants of the Caatinga is not ecologically affected by the presence of edges.Efeitos de borda são considerados fator-chave na regulação da estrutura de comunidades vegetais em diferentes ecossistemas. Entretanto, apesar dos poucos estudos relacionados, o efeito de borda parece não ser determinante em regiões semiáridas, como a floresta tropical seca brasileira, conhecida como Caatinga. Este estudo testou a hipótese nula de que a comunidade vegetal arbustivo-arbórea não sofre alterações em sua estrutura, riqueza e composição devido ao efeito de borda. Foram instaladas 24 parcelas (20 x 20 m em um fragmento de Caatinga arbórea, sendo 12 parcelas na borda do fragmento e 12 parcelas no seu interior. A riqueza, abundância e composição das espécies não diferiram estatisticamente entre as parcelas de borda e interior. Os resultados deste estudo corroboram um possível padr

β-Diversity of functional groups of woody plants in a tropical dry forest in Yucatan.

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Jorge Omar López-Martínez

Full Text Available Two main theories have attempted to explain variation in plant species composition (β-diversity. Niche theory proposes that most of the variation is related to environment (environmental filtering, whereas neutral theory posits that dispersal limitation is the main driver of β-diversity. In this study, we first explored how α- and β-diversity of plant functional groups defined by growth form (trees, shrubs and lianas, which represent different strategies of resource partitioning, and dispersal syndrome (autochory, anemochory and zoochory, which represent differences in dispersal limitation vary with successional age and topographic position in a tropical dry forest. Second, we examined the effects of environmental, spatial, and spatially-structured environmental factors on β-diversity of functional groups; we used the spatial structure of sampling sites as a proxy for dispersal limitation, and elevation, soil properties and forest stand age as indicators of environmental filtering. We recorded 200 species and 22,245 individuals in 276 plots; 120 species were trees, 41 shrubs and 39 lianas. We found that β-diversity was highest for shrubs, intermediate for lianas and lowest for trees, and was slightly higher for zoochorous than for autochorous and anemochorous species. All three dispersal syndromes, trees and shrubs varied in composition among vegetation classes (successional age and topographic position, whilst lianas did not. β-diversity was influenced mostly by proxies of environmental filtering, except for shrubs, for which the influence of dispersal limitation was more important. Stand age and topography significantly influenced α-diversity across functional groups, but showed a low influence on β-diversity -possibly due to the counterbalancing effect of resprouting on plant distribution and composition. Our results show that considering different plant functional groups reveals important differences in both α- and �

Electrical conductivity of the nutrient solution and plant density in aeroponic production of seed potato under tropical conditions (winter/spring

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Alex Humberto Calori

Full Text Available ABSTRACT The recent introduction in Brazil of production of quality seed potatoes in hydroponic systems, such as aeroponics, demands studies on the nutritional and crop management. Thus, this study evaluated the influence of electrical conductivity of the nutrient solution and plant density on the seed potato minitubers production in aeroponics system. The Agata and Asterix cultivars were produced in a greenhouse under tropical conditions (winter/spring. The experimental design was a randomized block in a split-split plot design. The plot consisted of 4 electrical conductivities of the nutrient solution (1.0; 2.0; 3.0; and 4.0 dS∙m−1; the subplot, of 4 plant densities (25; 44; 66; and 100 plants∙m−2; and the subsubplot, of the 2 potato cultivars (Ágata and Asterix, totaling 4 blocks. The 2.2 and 2.1 dS∙m−1 electrical conductivities yielded the highest productivity of seed potato minitubers, for Ágata and Asterix cultivars, respectively, regardless of plant density. For both cultivars, the highest yield was observed for the 100 plants∙m−2 density.

Microbiological air quality in an urban solid waste selection plant

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Angela Del Cimmuto

2010-03-01

Full Text Available

Background: Exposure to bioaerosols may pose health risks to workers operating in the processing of Urban Solid Waste (USW. The aim of this study is to evaluate microbiological air quality within an USW selection facility.

Methods: Nine sampling points in an USW selection plant situated in central-southern Italy were selected. One outdoor sampling point provided the background data. Sampling was performed on a yearly basis (2005 – 2009 upon request by the management of the selection plant. Total Mesophilic Counts (TMC, as well as fungal and Gram-negative concentrations were determined.

Results: The highest viable fungal particles concentrations (medians were found in waste delivery areas (about 20000 CFU/m3, while the lowest were found in the control rooms (485 – 967 CFU/m3. TMC (median was highest (6116 CFU/m3 at the delivery pit, followed by the machine shop (3147 CFU/m3, where no waste processing takes place. Medians of Gram-negative bacteria are below the suggested Occupational Exposure Limit of 1000 CFU/m3, although this limit was exceeded at several single time-points in the waste delivery areas, and also in a personnel resting room. The lowest Gram-negative contamination was found in the control rooms (medians <1 CFU/m3.

Conclusions: Some areas within a USW selection plant act as internal sources of contamination towards those areas where partially processed waste, or no waste at all, is present. Well-designed air flows, or carefullythought positioning of areas that are not directly involved in waste processing are necessary and effective in obtaining

Transcriptome profiling of low temperature-treated cassava apical shoots showed dynamic responses of tropical plant to cold stress

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An Dong

2012-02-01

Full Text Available Abstract Background Cassava is an important tropical root crop adapted to a wide range of environmental stimuli such as drought and acid soils. Nevertheless, it is an extremely cold-sensitive tropical species. Thus far, there is limited information about gene regulation and signalling pathways related to the cold stress response in cassava. The development of microarray technology has accelerated the study of global transcription profiling under certain conditions. Results A 60-mer oligonucleotide microarray representing 20,840 genes was used to perform transcriptome profiling in apical shoots of cassava subjected to cold at 7°C for 0, 4 and 9 h. A total of 508 transcripts were identified as early cold-responsive genes in which 319 sequences had functional descriptions when aligned with Arabidopsis proteins. Gene ontology annotation analysis identified many cold-relevant categories, including 'Response to abiotic and biotic stimulus', 'Response to stress', 'Transcription factor activity', and 'Chloroplast'. Various stress-associated genes with a wide range of biological functions were found, such as signal transduction components (e.g., MAP kinase 4, transcription factors (TFs, e.g., RAP2.11, and reactive oxygen species (ROS scavenging enzymes (e.g., catalase 2, as well as photosynthesis-related genes (e.g., PsaL. Seventeen major TF families including many well-studied members (e.g., AP2-EREBP were also involved in the early response to cold stress. Meanwhile, KEGG pathway analysis uncovered many important pathways, such as 'Plant hormone signal transduction' and 'Starch and sucrose metabolism'. Furthermore, the expression changes of 32 genes under cold and other abiotic stress conditions were validated by real-time RT-PCR. Importantly, most of the tested stress-responsive genes were primarily expressed in mature leaves, stem cambia, and fibrous roots rather than apical buds and young leaves. As a response to cold stress in cassava, an increase

Study Of Plant Regeneration Potential In Tropical Moist Deciduous Forest In Northern India

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Ashish K Mishra

2013-12-01

Full Text Available Regeneration patterns of species population can address climate change by adaptive evolution or by migrating association to survive in their favorable climate and finally decided to particular forest future. In this paper we examined the status of regeneration potential of tree species in tropical moist deciduous forest at Katerniaghat Wildlife Sanctuary, Northern India. To investigate tree, sapling and seedling population distribution, we examine regeneration status in 145 random plots in study area. Total 74 plant species of 60 genera belonging to 32 families out of which 71 species of trees, 56 of seedlings and 60 of saplings were found in the forest. On the basis of importance value index Mallotus philippensis, Tectona grandis, Shorea robusta, Syzygium cumini and Bombax ceiba have been found as dominant species in the study area. As far as the regeneration status is concerned, the maximum tree species (64% have been found in good regeneration category. Significant variations in species richness and population density, between three life form (i. e. tree, sapling and seedling have been found. In which only three new tree species Prosopis juliflora, Psidium guajava and Morus alba were added in sapling and seedling stage. It is major ecological concern that about 19 % economically important plant species like Madhuca longifolia, Terminalia elliptica, Buchanania cochinchinensis, some Ficus species etc. have been found in poor regeneration phage, whereas about 7% species found in no regeneration categories. International Journal of Environment, Volume-2, Issue-1, Sep-Nov 2013, Pages 153-163 DOI: http://dx.doi.org/10.3126/ije.v2i1.9218

Starch grains reveal early root crop horticulture in the Panamanian tropical forest.

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Piperno, D R; Ranere, A J; Holst, I; Hansell, P

2000-10-19

Native American populations are known to have cultivated a large number of plants and domesticated them for their starch-rich underground organs. Suggestions that the likely source of many of these crops, the tropical forest, was an early and influential centre of plant husbandry have long been controversial because the organic remains of roots and tubers are poorly preserved in archaeological sediments from the humid tropics. Here we report the occurrence of starch grains identifiable as manioc (Manihot esculenta Crantz), yams (Dioscorea sp.) and arrowroot (Maranta arundinacea L.) on assemblages of plant milling stones from preceramic horizons at the Aguadulce Shelter, Panama, dated between 7,000 and 5,000 years before present (BP). The artefacts also contain maize starch (Zea mays L.), indicating that early horticultural systems in this region were mixtures of root and seed crops. The data provide the earliest direct evidence for root crop cultivation in the Americas, and support an ancient and independent emergence of plant domestication in the lowland Neotropical forest.

Micro-organisms behind the pollination scenes: microbial imprint on floral nectar sugar variation in a tropical plant community.

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Canto, A; Herrera, C M

2012-11-01

Variation in the composition of floral nectar reflects intrinsic plant characteristics as well as the action of extrinsic factors. Micro-organisms, particularly yeasts, represent one extrinsic factor that inhabit the nectar of animal-pollinated flowers worldwide. In this study a 'microbial imprint hypothesis' is formulated and tested, in which it is proposed that natural community-wide variation in nectar sugar composition will partly depend on the presence of yeasts in flowers. Occurrence and density of yeasts were studied microscopically in single-flower nectar samples of 22 animal-pollinated species from coastal xeric and sub-humid tropical habitats of the Yucatán Peninsula, Mexico. Nectar sugar concentration and composition were concurrently determined on the same samples using high-performance liquid chromatography (HPLC) methods. Microscopical examination of nectar samples revealed the presence of yeasts in nearly all plant species (21 out of 22 species) and in about half of the samples examined (51·8 % of total, all species combined). Plant species and individuals differed significantly in nectar sugar concentration and composition, and also in the incidence of nectar yeasts. After statistically controlling for differences between plant species and individuals, nectar yeasts still accounted for a significant fraction of community-wide variance in all nectar sugar parameters considered. Significant yeast × species interactions on sugar parameters revealed that plant species differed in the nectar sugar correlates of variation in yeast incidence. The results support the hypothesis that nectar yeasts impose a detectable imprint on community-wide variation in nectar sugar composition and concentration. Since nectar sugar features influence pollinator attraction and plant reproduction, future nectar studies should control for yeast presence and examine the extent to which microbial signatures on nectar characteristics ultimately have some influence on

Plant protein and secondary metabolites influence diet selection in a mammalian specialist herbivore

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Ulappa, Amy C.; Kelsey, Rick G.; Frye, Graham G.; Rachlow, Janet L.; Shipley, Lisa A.; Bond, Laura; Pu, Xinzhu; Forbey, Jennifer Sorensen

2015-01-01

For herbivores, nutrient intake is limited by the relatively low nutritional quality of plants and high concentrations of potentially toxic defensive compounds (plant secondary metabolites, PSMs) produced by many plants. In response to phytochemical challenges, some herbivores selectively forage on plants with higher nutrient and lower PSM concentrations relative to other plants. Pygmy rabbits (Brachylagus idahoensis) are dietary specialists that feed on sagebrush (Artemisia spp.) and forage on specific plants more than others within a foraging patch. We predicted that the plants with evidence of heavy foraging (browsed plants) would be of higher dietary quality than plants that were not browsed (unbrowsed). We used model selection to determine which phytochemical variables best explained the difference between browsed and unbrowsed plants. Higher crude protein increased the odds that plants would be browsed by pygmy rabbits and the opposite was the case for certain PSMs. Additionally, because pygmy rabbits can occupy foraging patches (burrows) for consecutive years, their browsing may influence the nutritional and PSM constituents of plants at the burrows. In a post hoc analysis, we did not find a significant relationship between phytochemical concentrations, browse status and burrow occupancy length. We concluded that pygmy rabbits use nutritional and chemical cues while making foraging decisions. PMID:26366011

Plant breeding with marker-assisted selection in Brazil

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Ney Sussumu Sakiyama

2014-03-01

Full Text Available Over the past three decades, molecular marker studies reached extraordinary advances, especially for sequencing and bioinformatics techniques. Marker-assisted selection became part of the breeding program routines of important seed companies, in order to accelerate and optimize the cultivar developing processes. Private seed companies increasingly use marker-assisted selection, especially for the species of great importance to the seed market, e.g. corn, soybean, cotton, and sunflower. In the Brazilian public institutions few breeding programs use it efficiently. The possible reasons are: lack of know-how, lack of appropriate laboratories, few validated markers, high cost, and lack of urgency in obtaining cultivars. In this article we analyze the use and the constraints of marker-assisted selection in plant breeding programs of Brazilian public institutes

Vegetation and floristics of a lowland tropical rainforest in northeast Australia

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Apgaua, Deborah M. G.; Campbell, Mason J; Cox, Casey J; Crayn, Darren M; Ishida, Françoise Y; Laidlaw, Melinda J; Liddell, Michael J; Seager, Michael; Laurance, Susan G. W.

2016-01-01

Abstract Background Full floristic data, tree demography, and biomass estimates incorporating non-tree lifeforms are seldom collected and reported for forest plots in the tropics. Established research stations serve as important repositories of such biodiversity and ecological data. With a canopy crane setup within a tropical lowland rainforest estate, the 42-ha Daintree Rainforest Observatory (DRO) in Cape Tribulation, northern Australia is a research facility of international significance. We obtained an estimate of the vascular plant species richness for the site, by surveying all vascular plant species from various mature-phase, remnant and open vegetation patches within the site. We also integrate and report the demography and basal areas of trees ≥ 10 cm diameter at breast height (dbh) in a new 1-ha core plot, an extension to the pre-existing forest 1-ha plot under the canopy crane. In addition, we report for the canopy crane plot new demography and basal areas for smaller-size shrubs and treelets subsampled from nine 20 m2 quadrats, and liana basal area and abundance from the whole plot. The DRO site has an estimated total vascular plant species richness of 441 species, of which 172 species (39%) are endemic to Australia, and 4 species are endemics to the Daintree region. The 2 x 1-ha plots contains a total of 262 vascular plant species of which 116 (1531 individuals) are tree species ≥ 10 cm dbh. We estimate a stem basal area of 34.9 m2 ha-1, of which small stems (tree saplings and shrubs rainforests globally, our meta-analysis shows that DRO forests has a comparatively high stem density and moderate species diversity, due to the influence of cyclones. These data will provide an important foundation for ecological and conservation studies in lowland tropical forest. New information We present a floristic checklist, a lifeform breakdown, and demography data from two 1-ha rainforest plots from a lowland tropical rainforest study site. We also present a

High yielding tropical energy crops for bioenergy production: Effects of plant components, harvest years and locations on biomass composition.

Science.gov (United States)

Surendra, K C; Ogoshi, Richard; Zaleski, Halina M; Hashimoto, Andrew G; Khanal, Samir Kumar

2018-03-01

The composition of lignocellulosic feedstock, which depends on crop type, crop management, locations and plant parts, significantly affects the conversion efficiency of biomass into biofuels and biobased products. Thus, this study examined the composition of different parts of two high yielding tropical energy crops, Energycane and Napier grass, collected across three locations and years. Significantly higher fiber content was found in the leaves of Energycane than stems, while fiber content was significantly higher in the stems than the leaves of Napier grass. Similarly, fiber content was higher in Napier grass than Energycane. Due to significant differences in biomass composition between the plant parts within a crop type, neither biological conversion, including anaerobic digestion, nor thermochemical pretreatment alone is likely to efficiently convert biomass components into biofuels and biobased products. However, combination of anaerobic digestion with thermochemical conversion technologies could efficiently utilize biomass components in generating biofuels and biobased products. Copyright © 2017 Elsevier Ltd. All rights reserved.

Biogenic VOC Emissions from Tropical Landscapes

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Guenther, A.; Greenberg, J.; Harley, P.; Otter, L.; Vanni Gatti, L.; Baker, B.

2003-04-01

Biogenic VOC have an important role in determining the chemical composition of atmosphere. As a result, these compounds are important for visibility, biogeochemical cycling, climate and radiative forcing, and the health of the biosphere. Tropical landscapes are estimated to release about 80% of total global biogenic VOC emissions but have been investigated to lesser extent than temperate regions. Tropical VOC emissions are particularly important due to the strong vertical transport and the rapid landuse change that is occurring there. This presentation will provide an overview of field measurements of biogenic VOC emissions from tropical landscapes in Amazonia (Large-scale Biosphere-atmosphere experiment in Amazonia, LBA) Central (EXPRESSO) and Southern (SAFARI 2000) Africa, Asia and Central America. Flux measurement methods include leaf-scale (enclosure measurements), canopy-scale (above canopy tower measurements), landscape-scale (tethered balloon), and regional-scale (aircraft measurements) observations. Typical midday isoprene emission rates for different landscapes vary by more than a factor of 20 with the lowest emissions observed from degraded forests. Emissions of alpha-pinene vary by a similar amount with the highest emissions associated with landscapes dominated by light dependent monoterpene emitting plants. Isoprene emissions tend to be higher for neotropical forests (Amazon and Costa Rica) in comparison to Africa and Asian tropical forests but considerable differences are observed within regions. Strong seasonal variations were observed in both the Congo and the Amazon rainforests with peak emissions during the dry seasons. Substantial emissions of light dependent monoterpenes, methanol and acetone are characteristic of at least some tropical landscapes.

Ecophysiology of two tropical species in an abandoned eucalypt plantation: effect of plant litter removal and seasonality

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Frederico Lage-Pinto

2015-05-01

Full Text Available The effect of the removal of plant litter on photosynthetic variables (gas exchanges, chlorophyll a fluorescence, and content of photosynthetic pigments of the tropical species Xylopia sericea A. St.-Hil. and Siparuna guianensis Aubl. was evaluated in an abandoned plantation of eucalypt (Corymbia citriodora (Hook. K.D. Hill & L.A.S. Johnson (Myrtaceae. The study was conducted at the União Biological Reserve, Rio de Janeiro State, Brazil during the rainy and dry periods, after five years of litter removal. The removal of plant litter did not influence the ecophysiological responses of the species. There was however significant seasonal variation. During the dry period, intercellular CO2 concentration (Ci, transpiration (E, and stomatal conductance (gs were decreased, while intrinsic efficiency of water use (IWUE, non-photochemical quenching (NPQ, and carotenoid values increased, suggesting a protective strategy against stress. Nevertheless, the values for Fv/Fm (maximum quantum efficiency and Fm/Fo (ratio of fluorescence yields for open and closed states indicated that even during the dry period there was no reduction in photochemical activity in these species. Only S. guianensis exhibited a reduced net photosynthetic rate (A during the dry period. The data indicated that X. sericea was photosynthetically more efficient under conditions of low water availability and that a 5-year period of plant litter removal failed to produce differences in ecophysiological processes in the species analyzed.

The design and application of a radiological consequence model for tropical and subtropical regions

International Nuclear Information System (INIS)

Domel, R.U.; Harris, F.F.; Crawford, J.

1998-01-01

The post Chernobyl era has seen the development of a plethora of radiological consequence models. The information used in these models pertains mostly to temperate and cold climate data, with these data mostly being hard-wired into the body of the model. At the Australian Nuclear Science and Technology Organisation (ANSTO), a model is being developed with a user-friendly interface which will assess the radiological consequences, after an incident, in tropical and sub-tropical climates. The model combines specific regional data (South East Asia) with transfer parameters (soil to plant, plant to animal) obtained for tropical and sub-tropical regions. Flexibility has been incorporated into the the design of the model to allow application in other regions. Where the relevant data are not available, default temperate data are used whilst specific research will be initiated to determine the information required. A Geographic Information System (GIS) is used for the display of input and output data allowing quick access to not only the results but also to the underlying assumptions

Fire as a selective force in a Bornean tropical everwet forest

NARCIS (Netherlands)

Slik, J.W.F.; Breman, F.C.; Bernard, C.; Beek, van M.; Cannon, C.H.; Eichhorn, K.A.O.; Sidiyasa, K.

2010-01-01

Tree species rarely exposed to burning, like in everwet tropical forests, are unlikely to be fire adapted. Therefore, one could hypothesize that these species are affected equally by burning and that tree abundance changes are linked solely to fire behavior. Alternatively, if species do react

Determination of some elements in Ageratum conyziodes, a tropical medicinal plant, using instrumental neutron activation analysis

International Nuclear Information System (INIS)

Dim, L.A.; Funtua, I.I.; Umar, I.M.; Gwozdz, R.

2004-01-01

Instrumental neutron activation analysis was utilized for the multielemental determination of elements in the roots of Ageratum conyzoides, a tropical medicinal plant that is used locally for the cure of various diseases in Nigeria. The concentrations of Al, Ba, Br, Ca, Co, Cr, Fe, K, Mg, Mn, Na, Rb, Sc, Sr, V and Zn were analyzed with the 250 kW Triga Reactor at the Atominstitut, Vienna. The essential elements K, Na, Ca, Fe, Mg, Mn and Zn and the non-essential elements Al, Ba, Sr and Rb are present in significant concentrations. Other elements including Co, Cr, Sc and V are present at trace levels. The likely implication of these elements in restoring and maintaining good health is discussed. Quality control on the measurements was carried out by analyzing standard reference materials alongside the samples. (author)

Selection and verification of safety parameters in safety parameter display system for nuclear power plants

International Nuclear Information System (INIS)

Zhang Yuangfang

1992-02-01

The method and results for safety parameter selection and its verification in safety parameter display system of nuclear power plants are introduced. According to safety analysis, the overall safety is divided into six critical safety functions, and a certain amount of safety parameters which can represent the integrity degree of each function and the causes of change are strictly selected. The verification of safety parameter selection is carried out from the view of applying the plant emergency procedures and in the accident man oeuvres on a full scale nuclear power plant simulator

Tropical radioecology

CERN Document Server

Baxter, M

2012-01-01

Tropical Radioecology is a guide to the wide range of scientific practices and principles of this multidisciplinary field. It brings together past and present studies in the tropical and sub-tropical areas of the planet, highlighting the unique aspects of tropical systems. Until recently, radioecological models for tropical environments have depended upon data derived from temperate environments, despite the differences of these regions in terms of biota and abiotic conditions. Since radioactivity can be used to trace environmental processes in humans and other biota, this book offers examples of studies in which radiotracers have been used to assess biokinetics in tropical biota. Features chapters, co-authored by world experts, that explain the origins, inputs, distribution, behaviour, and consequences of radioactivity in tropical and subtropical systems. Provides comprehensive lists of relevant data and identifies current knowledge gaps to allow for targeted radioecological research in the future. Integrate...

Chronic human disturbance affects plant trait distribution in a seasonally dry tropical forest

Science.gov (United States)

Sfair, Julia C.; de Bello, Francesco; de França, Thaysa Q.; Baldauf, Cristina; Tabarelli, Marcelo

2018-02-01

The effects of human disturbance on biodiversity can be mediated by environmental conditions, such as water availability, climate and nutrients. In general, disturbed, dry or nutrient-depleted soils areas tend to have lower taxonomic diversity. However, little is known about how these environmental conditions affect functional composition and intraspecific variability in tropical dry forests. We studied a seasonally dry tropical forest (SDTF) under chronic anthropogenic disturbance (CAD) along rainfall and soil nutrient gradients to understand how these factors influence the taxonomic and functional composition. Specifically we evaluated two aspects of CAD, wood extraction and livestock pressure (goat and cattle grazing), along soil fertility and rainfall gradients on shrub and tree traits, considering species turnover and intraspecific variability. In addition, we also tested how the traits of eight populations of the most frequent species are affected by wood extraction, livestock pressure, rainfall and soil fertility. In general, although CAD and environmental gradients affected each trait of the most widespread species differently, the most abundant species also had a greater variation of traits. Considering species turnover, wood extraction is associated with species with a smaller leaf area and lower investment in leaf mass, probably due to the indirect effects of this disturbance type on the vegetation, i.e. the removal of branches and woody debris clears the vegetation, favouring species that minimize water loss. Livestock pressure, on the other hand, affected intraspecific variation: the herbivory caused by goats and cattle promoted individuals which invest more in wood density and leaf mass. In this case, the change of functional composition observed is a direct effect of the disturbance, such as the decrease of palatable plant abundance by goat and cattle herbivory. In synthesis, CAD, rainfall and soil fertility can affect trait distribution at community

SRTM-DEM and Landsat ETM+ data for mapping tropical dry forest cover and biodiversity assessment in Nicaragua

Science.gov (United States)

S.E. Sesnie; S.E. Hagell; S.M. Otterstrom; C.L. Chambers; B.G. Dickson

2008-01-01

Tropical dry and deciduous forest comprises as much as 42% of the world’s tropical forests, but has received far less attention than forest in wet tropical areas. Land use change threatens to greatly reduce the extent of dry forest that is known to contain high levels of plant and animal diversity. Forest fragmentation may further endanger arboreal mammals that play...

Experimental infection of plants with an herbivore-associated bacterial endosymbiont influences herbivore host selection behavior.

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Thomas Seth Davis

Full Text Available Although bacterial endosymbioses are common among phloeophagous herbivores, little is known regarding the effects of symbionts on herbivore host selection and population dynamics. We tested the hypothesis that plant selection and reproductive performance by a phloem-feeding herbivore (potato psyllid, Bactericera cockerelli is mediated by infection of plants with a bacterial endosymbiont. We controlled for the effects of herbivory and endosymbiont infection by exposing potato plants (Solanum tuberosum to psyllids infected with "Candidatus Liberibacter solanacearum" or to uninfected psyllids. We used these treatments as a basis to experimentally test plant volatile emissions, herbivore settling and oviposition preferences, and herbivore population growth. Three important findings emerged: (1 plant volatile profiles differed with respect to both herbivory and herbivory plus endosymbiont infection when compared to undamaged control plants; (2 herbivores initially settled on plants exposed to endosymbiont-infected psyllids but later defected and oviposited primarily on plants exposed only to uninfected psyllids; and (3 plant infection status had little effect on herbivore reproduction, though plant flowering was associated with a 39% reduction in herbivore density on average. Our experiments support the hypothesis that plant infection with endosymbionts alters plant volatile profiles, and infected plants initially recruited herbivores but later repelled them. Also, our findings suggest that the endosymbiont may not place negative selection pressure on its host herbivore in this system, but plant flowering phenology appears correlated with psyllid population performance.

Oligarchic forests of economic plants in amazonia: utilization and conservation of an important tropical resource.

Science.gov (United States)

Peters, C M; Balick, M J; Kahn, F; Anderson, A B

1989-12-01

Tropical forests dominated by only one or two tree species occupy tens of millions of hectares in Ammonia In many cases, the dominant species produce fruits, seeds, or oils of economic importance. Oligarchic (Gr. oligo = few, archic = dominated or ruled by) forests of six economic species, i. e., Euterpe oleracea, Grias peruviana, Jessenia bataua, Mauritia flexuosa, Myrciaria dubia, and Orbignya phalerata, were studied in Brazil and Peru Natural populations of these species contain from 100 to 3,000 conspecific adult trees/ha and produce up to 11.1 metric tons of fruit/hd/yr. These plant populations are utilized and occasionally managed, by rural inhabitants in the region. Periodic fruit harvests, if properly controlled have only a minimal impact on forest structure and function, yet can generate substantial economic returns Market-oriented extraction of the fruits produced by oligarchic forests appears to represent a promising alternative for reconciling the development and conservation of Amazonian forests.

[Neotropical plant morphology].

Science.gov (United States)

Pérez-García, Blanca; Mendoza, Aniceto

2002-01-01

An analysis on plant morphology and the sources that are important to the morphologic interpretations is done. An additional analysis is presented on all published papers in this subject by the Revista de Biología Tropical since its foundation, as well as its contribution to the plant morphology development in the neotropics.

Analysis of vitamin C in selected medicinal plants

International Nuclear Information System (INIS)

Hussain, I.

2011-01-01

Vitamin C or ascorbic acid, a very useful constituent of redox mechanism is used in medicine and also added in manufactured food for anti-oxidation. A UV-spectrophotometric method was used for the determination of Vitamin C in 4 different medicinal plants. High amount of Vitamin C 160 mg/100 g was found in Citrulus colcocynthis, followed by Hippophae rhamonides oil 136.1 mg/100g. A relatively low concentration of Vitamin C was recorded in Glycyrhiza glabra 56.2 mg/100g and Withinia somnifera 51.50 mg/100 g. The presence of high concentration of Vitamin C in selected medicinal plants might be responsible for their therapeutic effects and uses in the traditional system of medicine. (author)

Earthworms and Plant Residues Modify Nematodes in Tropical Cropping Soils (Madagascar): A Mesocosm Experiment

International Nuclear Information System (INIS)

Villenave, C.; Kichenin, E.; Djigal, D.; Blanchart, E.; Rabary, B.; Djigal, D.

2010-01-01

Free-living nematodes present several characteristics that have led to their use as bio indicators of soil quality. Analyzing the structure of nematofauna is a pertinent way to understand soil biological processes. Earthworms play an important role in soil biological functioning and organic matter dynamics. Their effects on soil nematofauna have seldom been studied. We studied the effect of the tropical endogeic earthworm, Pontoscolex corethrurus, on nematode community structure in a 5-month field mesocosm experiment conducted in Madagascar. Ten different treatments with or without earthworms and with or without organic residues (rice, soybean) were compared. Organic residues were applied on the soil surface or mixed with the soil. The abundance of nematodes (bacterial and fungal feeders) was higher in presence of P. corethrurus than in their absence. The type of plant residues as well as their localisation had significant effects on the abundance and composition of soil nematodes. The analysis of nematode community structure showed that earthworm activity led to an overall activation of the microbial compartment without specific stimulation of the bacterial or fungal compartment.

Earthworms and Plant Residues Modify Nematodes in Tropical Cropping Soils (Madagascar: A Mesocosm Experiment

Directory of Open Access Journals (Sweden)

Cécile Villenave

2010-01-01

Full Text Available Free-living nematodes present several characteristics that have led to their use as bioindicators of soil quality. Analyzing the structure of nematofauna is a pertinent way to understand soil biological processes. Earthworms play an important role in soil biological functioning and organic matter dynamics. Their effects on soil nematofauna have seldom been studied. We studied the effect of the tropical endogeic earthworm, Pontoscolex corethrurus, on nematode community structure in a 5-month field mesocosm experiment conducted in Madagascar. Ten different treatments with or without earthworms and with or without organic residues (rice, soybean were compared. Organic residues were applied on the soil surface or mixed with the soil. The abundance of nematodes (bacterial and fungal feeders was higher in presence of P. corethrurus than in their absence. The type of plant residues as well as their localisation had significant effects on the abundance and composition of soil nematodes. The analysis of nematode community structure showed that earthworm activity led to an overall activation of the microbial compartment without specific stimulation of the bacterial or fungal compartment.

Community patterns of tropical tree phenology derived from Unmanned Aerial Vehicle images: intra- and interspecific variation, association with species plant traits, and response to interannual climate variation

Science.gov (United States)

Bohlman, Stephanie; Rifai, Sami; Park, John; Dandois, Jonathan; Muller-Landau, Helene

2017-04-01

Phenology is a key life history trait of plant species and critical driver of ecosystem processes. There is strong evidence that phenology is shifting in temperate ecosystems in response to climate change, but tropical forest phenology remains poorly quantified and understood. A key challenge is that tropical forests contain hundreds of plant species with a wide variety of phenological patterns, which makes it difficult to collect sufficient ground-based field data to characterize individual tropical tree species phenologies. Satellite-based observations, an important source of phenology data in northern latitudes, are hindered by frequent cloud cover in the tropics. To quantify phenology over a large number of individuals and species, we collected bi-weekly images from unmanned aerial vehicles (UAVs) in the well-studied 50-ha forest inventory plot on Barro Colorado Island, Panama. The objective of this study is to quantify inter- and intra-specific responses of tropical tree leaf phenology to environmental variation over large spatial scales and identify key environmental variables and physiological mechanisms underpinning phenological variation. Between October 2014 and December 2015 and again in May 2015, we collected a total of 35 sets of UAV images, each with continuous coverage of the 50-ha plot, where every tree ≥ 1 cm DBH is mapped. UAV imagery was corrected for exposure, orthorectified, and then processed to extract spectral, texture, and image information for individual tree crowns, which was then used as inputs for a machine learning algorithm that successfully predicted the percentages of leaf, branch, and flower cover for each tree crown (r2=0.76 between observed and predicted percent branch cover for individual tree crowns). We then quantified cumulative annual deciduousness for each crown by fitting a non-parametric curve of flexible shape to its predicted percent branch time series and calculated the area under the curve. We obtained the species

Heavy metal content of selected African leafy vegetables planted in ...

African Journals Online (AJOL)

Heavy metal content of selected African leafy vegetables planted in urban and peri-urban Nairobi, Kenya. ... African Journal of Environmental Science and Technology ... Government clean-up activities and monitoring of waste disposal is ...

In vitro antioxidant assay of selected aqueous plant extracts and their polyherbal formulation

Directory of Open Access Journals (Sweden)

Ganga Raju M.

2015-04-01

Full Text Available To support the use of selected plant extracts in Ayurveda, naturopathy, the antioxidant potential of the aqueous extract of Vincarosea (VR, Gymnemasylvestre (GS, Tinosporacordifolia (TC and Emblicaofficinalis (EO and their mixture (PHF of Indian origin was investigated for in vitro antioxidant activity by using in vitro models like superoxide, hydroxyl radical scavenging activity and lipid peroxide inhibition assay. The results were compared with standard (ascorbic acid, a known antioxidant. The various phytoconstituents identified in the above selected plants extracts were poly phenols, flavonoids, terpenoids, tannins, alkaloids. The terpenoids were reported to protect lipids, blood and body fluids against the attack of free radicals, some types of reactive oxygen, hydroxylic groups, peroxides and superoxide radicals. The presence of these phytoconstituents in selected plants might be responsible for antioxidant activity with that of known antioxidant ascorbic acid.

Parameterization of Leaf-Level Gas Exchange for Plant Functional Groups From Amazonian Seasonal Tropical Rain Forest

Science.gov (United States)

Domingues, T. F.; Berry, J. A.; Ometto, J. P.; Martinelli, L. A.; Ehleringer, J. R.

2004-12-01

Plant communities exert strong influence over the magnitude of carbon and water cycling through ecosystems by controlling photosynthetic gas exchange and respiratory processes. Leaf-level gas exchange fluxes result from a combination of physiological properties, such as carboxylation capacity, respiration rates and hydraulic conductivity, interacting with environmental drivers such as water and light availability, leaf-to-air vapor pressure deficit, and temperature. Carbon balance models concerned with ecosystem-scale responses have as a common feature the description of eco-physiological properties of vegetation. Here we focus on the parameterization of ecophysiological gas-exchange properties of plant functional groups from a pristine Amazonian seasonally dry tropical rain forest ecosystem (FLONA-Tapajós, Santarém, PA, Brazil). The parameters were specific leaf weight, leaf nitrogen content, leaf carbon isotope ratio, maximum photosynthetic assimilation rate, photosynthetic carboxylation capacity, dark respiration rates, and stomatal conductance to water vapor. Our plant functional groupings were lianas at the top of the canopy, trees at the top of the canopy, mid-canopy trees and undestory trees. Within the functional groups, we found no evidence that leaves acclimated to seasonal changes in precipitation. However, there were life-form dependent distinctions when a combination of parameters was included. Top-canopy lianas were statistically different from top-canopy trees for leaf carbon isotope ratio, maximum photosynthetic assimilation rate, and stomatal conductance to water vapor, suggesting that lianas are more conservative in the use of water, causing a stomatal limitation on photosynthetic assimilation. Top-canopy, mid canopy and understory groupings were distinct for specific leaf weight, leaf nitrogen content, leaf carbon isotope ratio, maximum photosynthetic assimilation rate, and photosynthetic carboxylation capacity. The recognition that plant

Successes and failures of small ruminant breeding programmes in the tropics: a review

NARCIS (Netherlands)

Kosgey, I.S.; Baker, R.L.; Udo, H.M.J.; Arendonk, van J.A.M.

2006-01-01

Despite the large numbers and importance of adapted indigenous sheep and goats in the tropics, information on sustainable conventional breeding programmes for them is scarce and often unavailable. This paper reviews within-breed selection strategies for indigenous small ruminants in the tropics,

Oral acute toxicity study of selected botanical pesticide plants used ...

African Journals Online (AJOL)

aghomotsegin

The widely used plants were identified and selected for biosafety assessments namely: Ocimum ... estimated that hardly 0.1% of the agrochemicals used for .... electric motor. ... amounts of the vehicle substances (distilled water for ethanol and.

Bioquality Hotspots in the Tropical African Flora.

Science.gov (United States)

Marshall, Cicely A M; Wieringa, Jan J; Hawthorne, William D

2016-12-05

Identifying areas of high biodiversity is an established way to prioritize areas for conservation [1-3], but global approaches have been criticized for failing to render global biodiversity value at a scale suitable for local management [4-6]. We assembled 3.1 million species distribution records for 40,401 vascular plant species of tropical Africa from sources including plot data, herbarium databases, checklists, and the Global Biodiversity Information Facility (GBIF) and cleaned the records for geographic accuracy and taxonomic consistency. We summarized the global ranges of tropical African plant species into four weighted categories of global rarity called Stars. We applied the Star weights to summaries of species distribution data at fine resolutions to map the bioquality (range-restricted global endemism) of areas [7]. We generated confidence intervals around bioquality scores to account for the remaining uncertainty in the species inventory. We confirm the broad significance of the Horn of Africa, Guinean forests, coastal forests of East Africa, and Afromontane regions for plant biodiversity but also reveal the variation in bioquality within these broad regions and others, particularly at local scales. Our framework offers practitioners a quantitative, scalable, and replicable approach for measuring the irreplaceability of particular local areas for global biodiversity conservation and comparing those areas within their global and regional context. Copyright © 2016 Elsevier Ltd. All rights reserved.

Wastewater sludge treatment at selected wastewater treatment plants of the region Banska Bystrica

International Nuclear Information System (INIS)

Samesova, D.; Mitterpach, J.; Martinkova, A.

2014-01-01

The management of sewage sludges in water treatment plants of Banska Bystrica region. The paper deals with the problems of sewage sludge in wastewater treatment plants, its origin and possibilities how to use it in accordance with the current legislation of the Slovak Republic. We described radioactive pollution of sewage sludges. The paper consists of review of sludge production and its usage in the Slovak Republic and in selected states of the European Union. The paper deals with the sludge treatment in selected wastewater treatment plants in Banska Bystrica region in the context of biogas production and its usage by the help of the electricity and heat production. (authors)

Selective logging and fire as drivers of alien grass invasion in a Bolivian tropical dry forest

NARCIS (Netherlands)

Veldman, J.W.; Mostacedo, B.; Peña-Claros, M.; Putz, F.E.

2009-01-01

Logging is an integral component of most conceptual models that relate human land-use and climate change to tropical deforestation via positive-feedbacks involving fire. Given that grass invasions can substantially alter fire regimes, we studied grass distributions in a tropical dry forest 1-5 yr

Calibration and validation of models for short-term decomposition and N mineralization of plant residues in the tropics

Directory of Open Access Journals (Sweden)

Alexandre Ferreira do Nascimento

2012-12-01

Full Text Available Insight of nutrient release patterns associated with the decomposition of plant residues is important for their effective use as a green manure in food production systems. Thus, this study aimed to evaluate the ability of the Century, APSIM and NDICEA simulation models for predicting the decomposition and N mineralization of crop residues in the tropical Atlantic forest biome, Brazil. The simulation models were calibrated based on actual decomposition and N mineralization rates of three types of crop residues with different chemical and biochemical composition. The models were also validated for different pedo-climatic conditions and crop residues conditions. In general, the accuracy of decomposition and N mineralization improved after calibration. Overall RMSE values for the decomposition and N mineralization of the crop materials varied from 7.4 to 64.6% before models calibration compared to 3.7 to 16.3 % after calibration. Therefore, adequate calibration of the models is indispensable for use them under humid tropical conditions. The NDICEA model generally outperformed the other models. However, the decomposition and N mineralization was not very accurate during the first 30 days of incubation, especially for easily decomposable crop residues. An additional model variable may be required to capture initial microbiological growth as affected by the moisture dynamics of the residues, as is the case in surface residues decomposition models.

Manufacturing plant location selection in logistics network using Analytic Hierarchy Process

Directory of Open Access Journals (Sweden)

Ping-Yu Chang

2015-11-01

Full Text Available Purpose: In recent years, numerous companies have moved their manufacturing plants to China to capitalize on lower cost and tax. Plant location has such an impact on cost, stocks, and logistics network but location selection in the company is usually based on subjective preference of high ranking managers. Such a decision-making process might result in selecting a location with a lower fixed cost but a higher operational cost. Therefore, this research adapts real data from an electronics company to develop a framework that incorporates both quantitative and qualitative factors for selecting new plant locations. Design/methodology/approach: In-depth interviews were conducted with 12 high rank managers (7 of them are department manager, 2 of them are vice-president, 1 of them is senior engineer, and 2 of them are plant manager in the departments of construction, finance, planning, production, and warehouse to determine the important factors. A questionnaire survey is then conducted for comparing factors which are analyzed using the Analytic Hierarchy Process (AHP. Findings: Results show that the best location chosen by the developed framework coincides well with the company’s primal production base. The results have been presented to the company’s high ranking managers for realizing the accuracy of the framework. Positive responses of the managers indicate usefulness of implementing the proposed model into reality, which adds to the value of this research. Practical implications: The proposed framework can save numerous time-consuming meetings called to compromise opinions and conflictions from different departments in location selection. Originality/value: This paper adapts the Analytic Hierarchy Process (AHP to incorporate quantitative and qualitative factors which are obtained through in-depth interviews with high rank managers in a company into the location decision.

Soil nitrogen levels are linked to decomposition enzyme activities along an urban-remote tropical forest gradient

Science.gov (United States)

D. F. Cusack

2013-01-01

Urban areas in tropical regions are expanding rapidly, with significant potential to affect local ecosystem dynamics. In particular, nitrogen (N) availability may increase in urban-proximate forests because of atmospheric N deposition. Unlike temperate forests, many tropical forests on highly weathered soils have high background N availability, so plant growth is...

Leaf litter decomposition rates increase with rising mean annual temperature in Hawaiian tropical montane wet forests

Science.gov (United States)

Lori D. Bothwell; Paul C. Selmants; Christian P. Giardina; Creighton M. Litton

2014-01-01

Decomposing litter in forest ecosystems supplies nutrients to plants, carbon to heterotrophic soil microorganisms and is a large source of CO2 to the atmosphere. Despite its essential role in carbon and nutrient cycling, the temperature sensitivityof leaf litter decay in tropical forest ecosystems remains poorly resolved, especially in tropical...

Utilization of geothermal heat in tropical fruit-drying process

Energy Technology Data Exchange (ETDEWEB)

Chen, B.H.; Lopez, L.P.; King, R.; Fujii, J.; Tanaka, M.

1982-10-01

The power plant utilizes only the steam portion of the HGP-A well production. There are approximately 50,000 pounds per hour of 360/sup 0/F water produced (approximately 10 million Btu per hour) and the water is currently not used and is considered a waste. This tremendous resource could very well be used in applications such as food processing, food dehydration and other industrial processing that requires low-grade heat. One of the applications is examined, namely the drying of tropical fruits particularly the papaya. The papaya was chosen for the obvious reason that it is the biggest crop of all fruits produced on the Big Island. A conceptual design of a pilot plant facility capable of processing 1000 pounds of raw papaya per day is included. This facility is designed to provide a geothermally heated dryer to dehydrate papayas or other tropical fruits available on an experimental basis to obtain data such as drying time, optimum drying temperature, etc.

The draft genome of tropical fruit durian (Durio zibethinus).

Science.gov (United States)

Teh, Bin Tean; Lim, Kevin; Yong, Chern Han; Ng, Cedric Chuan Young; Rao, Sushma Ramesh; Rajasegaran, Vikneswari; Lim, Weng Khong; Ong, Choon Kiat; Chan, Ki; Cheng, Vincent Kin Yuen; Soh, Poh Sheng; Swarup, Sanjay; Rozen, Steven G; Nagarajan, Niranjan; Tan, Patrick

2017-11-01

Durian (Durio zibethinus) is a Southeast Asian tropical plant known for its hefty, spine-covered fruit and sulfury and onion-like odor. Here we present a draft genome assembly of D. zibethinus, representing the third plant genus in the Malvales order and first in the Helicteroideae subfamily to be sequenced. Single-molecule sequencing and chromosome contact maps enabled assembly of the highly heterozygous durian genome at chromosome-scale resolution. Transcriptomic analysis showed upregulation of sulfur-, ethylene-, and lipid-related pathways in durian fruits. We observed paleopolyploidization events shared by durian and cotton and durian-specific gene expansions in MGL (methionine γ-lyase), associated with production of volatile sulfur compounds (VSCs). MGL and the ethylene-related gene ACS (aminocyclopropane-1-carboxylic acid synthase) were upregulated in fruits concomitantly with their downstream metabolites (VSCs and ethylene), suggesting a potential association between ethylene biosynthesis and methionine regeneration via the Yang cycle. The durian genome provides a resource for tropical fruit biology and agronomy.

Forests to fields. Restoring tropical lands to agriculture.

Science.gov (United States)

Wood, D

1993-04-01

In discussing land use in tropical forest regions, there is an emphasis on the following topics: the need for the expansion of cropping areas, the precedent for use of the tropical forest for cropping based on past use patterns, the pressure from conservationists against cropping, debunking the mythology that forests are "natural" and refuting the claims that forest clearance is not reversible, the archeological evidence of past forest use for agricultural purposes, abandonment of tropical land to forest, and rotation of forest and field. The assumption is that the way to stop food importation is to increase crop production in the tropics. Crop production can be increased through 1) land intensification or clearing new land, 2) output per unit of land increases, or 3) reallocation to agriculture land previously cleared and overgrown with tropical forest. "Temporary" reuse of land, which reverted back to tropical forest, is recommended. This reuse would ease population pressure, and benefit bioconservation, while populations stabilize and further progress is made in international plant breeding. The land would eventually be returned to a forest state. Conservation of tropical forest areas should be accomplished, after an assessment has been made of its former uses. Primary forests need to identified and conversion to farming ceased. Research needs to be directed to understanding the process of past forest regeneration, and to devising cropping systems with longterm viability. The green revolution is unsuitable for traditional cropping systems, is contrary to demands of international funding agencies for sustainability, and is not affordable by most poor farmers. Only .48 million sq. km of closed forest loss was in tropical rainforests; 6.53 million sq. km was lost from temperate forests cleared for intensive small-scale peasant farming. The use of tropical forest land for farming has some benefits; crops in the wetter tropics are perennial, which would "reduce

Alternative plant protein sources for pigs and chickens in the tropics – nutritional value and constraints: a review

Directory of Open Access Journals (Sweden)

Carlos E. Lascano

2012-01-01

Full Text Available In the tropics, a large number of smallholder farms contribute significantly to food security by raising pigs and poultry for domestic consumption and for sale on local markets. The high cost and, sometimes, the lack of availability of commercial protein supplements is one of the main limitations to efficient animal production by smallholders. Locally-grown forages and grain legumes offer ecological benefits such as nitrogen fixation, soil improvement, and erosion control which contribute to improve cropping efficiency. Besides these agronomical assets, they can be used as animal feeds in mixed farming systems. In this paper we review options to include locally-grown forages and grain legumes as alternative protein sources in the diets of pigs and poultry in order to reduce farmers’ dependence on externally-purchased protein concentrates. The potential nutritive value of a wide range of forages and grain legumes is presented and discussed. The influence of dietary fibre and plant secondary metabolites contents and their antinutritive consequences on feed intake, digestive processes and animal performances are considered according to the varying composition in those compounds of the different plant species and cultivars covered in this review. Finally, methods to overcome the antinutritive attributes of the plant secondary metabolites using heat, chemical or biological treatment are reviewed regarding their efficiency and their suitability in low input farming systems.

Antileishmanial Activity of Selected Turkish Medicinal Plants ...

African Journals Online (AJOL)

Tropical Journal of Pharmaceutical Research. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 13, No 12 (2014) >. Log in or Register to get access to full text downloads.

Seed-deposition and recruitment patterns of Clusia species in a disturbed tropical montane forest in Bolivia

Science.gov (United States)

Saavedra, Francisco; Hensen, Isabell; Apaza Quevedo, Amira; Neuschulz, Eike Lena; Schleuning, Matthias

2017-11-01

Spatial patterns of seed dispersal and recruitment of fleshy-fruited plants in tropical forests are supposed to be driven by the activity of animal seed dispersers, but the spatial patterns of seed dispersal, seedlings and saplings have rarely been analyzed simultaneously. We studied seed deposition and recruitment patterns of three Clusia species in a tropical montane forest of the Bolivian Andes and tested whether these patterns changed between habitat types (forest edge vs. forest interior), distance to the fruiting tree and consecutive recruitment stages of the seedlings. We recorded the number of seeds deposited in seed traps to assess the local seed-deposition pattern and the abundance and distribution of seedlings and saplings to evaluate the spatial pattern of recruitment. More seeds were removed and deposited at the forest edge than in the interior. The number of deposited seeds decreased with distance from the fruiting tree and was spatially clustered in both habitat types. The density of 1-yr-old seedlings and saplings was higher at forest edges, whereas the density of 2-yr-old seedlings was similar in both habitat types. While seedlings were almost randomly distributed, seeds and saplings were spatially clustered in both habitat types. Our findings demonstrate systematic changes in spatial patterns of recruits across the plant regeneration cycle and suggest that the differential effects of biotic and abiotic factors determine plant recruitment at the edges and in the interior of tropical montane forests. These differences in the spatial distribution of individuals across recruitment stages may have strong effects on plant community dynamics and influence plant species coexistence in disturbed tropical forests.

Seismic safety margins research program. Phase I final report - Plant/site selection and data collection (Project I)

International Nuclear Information System (INIS)

Chuang, T.Y.

1981-07-01

Project I of Phase I of the Seismic Safety Margins Research Program (SSMRP) comprised two parts: the selection of a representative nuclear power plant/site for study in Phase I and the collection of data needed by the other SSMRP projects. Unit 1 of the Zion Nuclear Power Plant in Zion, Illinois, was selected for the SSMRP Phase I studies. Unit 1 of the Zion plant has been validated as a good choice for the Phase I study plant. Although no single nuclear power plant can represent all such plants equally well, selection criteria were developed to maximize the generic implications of Phase I of the SSMRP. On the basis of the selection criteria, the Zion plant and its site were found to be reasonably representative of operating and future plants with regard to its nuclear steam supply system; the type of containment structure (prestressed concrete); its electrical capacity (1100 MWe); its location (the Midwest); the peak seismic acceleration used for design (0.17g); and the properties of the underlying soil (the low-strain shear-wave velocity is 1650 ft/s in a 50- to 100-ft-thick layer of soil overlying sedimentary bedrock). (author)

Assessing diversity and phytoremediation potential of seagrass in tropical region

Science.gov (United States)

Seagrass ecosystem is one of the most important resources in the coastal areas. Seagrasses support and provide habitats for many coastal organisms in tropical region. Seagrasses are specialized marine flowering plants that have adapted to the nearshore environment with heterogeneous landscape struct...

Soil-mediated filtering organizes tree assemblages in regenerating tropical forests

NARCIS (Netherlands)

Pinho, Bruno Ximenes; Melo, de Felipe Pimentel Lopes; Arroyo-Rodríguez, Víctor; Pierce, Simon; Lohbeck, Madelon; Tabarelli, Marcelo

2018-01-01

Secondary forests are increasingly dominant in human-modified tropical landscapes, but the drivers of forest recovery remain poorly understood. Soil conditions influence plant community composition, and are expected to change over a gradient of succession. However, the role of soil conditions as

Response of eight tropical plants to enhanced ammonia deposition under field, conditions prevalent with SO{sub 2} and NH{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Rao, M.V.; Khijneri, S.; Dubey, P.S.; Kumawat, D.M. [Vikram University, Ujjain (India). School of Studies in Botany

1993-12-01

The impact of SO{sub 2} on the deposition of ammonia and the response of eight tropical tree species to excess deposition of ammonia was investigated. This was achieved by studying physiological aspects like total sugars, protein, nitrate reductace (NR) activity, organic/inorganic nitrogen ratio, specific leaf area and foliar injury in plants growing under field conditions prevalent with SO{sub 2} and NH{sub 3}. Analysis of water soluble substances present on foliar surfaces of the trees indicated enhanced NH{sub 4}{sup +} deposition and thereby result in enhanced foliar protein contents. Though the enhanced nitrogen was almost the same in different plants, the plants exhibited differential metabolic disturbances. Critical analysis of the reults indicated three distinct types of plant response. Plants like {ital Azadirachta indica}, {ital Acacia auriculiformis} and {ital Bambusa arundinaceae} maintained enhanced total sugars and NR activity and incorporated excess NH{sub 4}{sup +} into proteins, thus enabling the plant to compensate/alleviate SO{sub 2} induced injury. Ficus benghalensis and Ficus religiosa maintained unaltered total sugars and NR activity and could partly incorporate NH{sub 4}{sup +} into proteins, thus modifying rhe SO{sub 2} impact to some extent. {ital Dalbergia sissoo}, {ital Eucalyptus rostrat}a and {ital Mangifera indica} could not incorporate the excess NH{sub 4}{sup +}, mainly due to declined total sugars. The results indicate the ability of a plant to undergo species specific metabolic changes in order to cope with the excess nitrogen deposition, which may ultimately result in increasing or decreasing tolerance to SO{sub 2}. 23 refs., 3 figs., 9 tabs.

Trace element uptake by Eleocharis equisetina (spike rush) in an abandoned acid mine tailings pond, northeastern Australia: Implications for land and water reclamation in tropical regions

International Nuclear Information System (INIS)

Lottermoser, Bernd G.; Ashley, Paul M.

2011-01-01

This study was conducted to determine the uptake of trace elements by the emergent wetland plant species Eleocharis equisetina at the historic Jumna tin processing plant, tropical Australia. The perennial emergent sedge was found growing in acid waters (pH 2.45) and metal-rich tailings (SnAsCuPbZn). E. equisetina displayed a pronounced acid tolerance and tendency to exclude environmentally significant elements (Al, As, Cd, Ce, Co, Cu, Fe, La, Ni, Pb, Se, Th, U, Y, Zn) from its above-substrate biomass. This study demonstrates that geobotanical and biogeochemical examinations of wetland plants at abandoned mined lands of tropical areas can reveal pioneering, metal-excluding macrophytes. Such aquatic macrophytes are of potential use in the remediation of acid mine waters and sulfidic tailings and the reclamation of disturbed acid sulfate soils in subtropical and tropical regions. - Highlights: → In tropical Australia, Eleocharis equisetina grows in an acid mine tailings pond. → Eleocharis equisetina excludes environmentally significant elements from its biomass. → Inspections of equatorial mined lands can reveal metal-excluding aquatic macrophytes. → Such plants are of use in land and water remediation in tropical regions. - The metal-excluding aquatic macrophyte Eleocharis equisetina is of use in land and water remediation in tropical regions.

Trace element uptake by Eleocharis equisetina (spike rush) in an abandoned acid mine tailings pond, northeastern Australia: Implications for land and water reclamation in tropical regions

Energy Technology Data Exchange (ETDEWEB)

Lottermoser, Bernd G., E-mail: Bernd.Lottermoser@utas.edu.au [School of Earth Sciences, University of Tasmania, Private Bag 79, Hobart, Tasmania 7001 (Australia); Ashley, Paul M. [Earth Sciences, University of New England, Armidale, New South Wales 2351 (Australia)

2011-10-15

This study was conducted to determine the uptake of trace elements by the emergent wetland plant species Eleocharis equisetina at the historic Jumna tin processing plant, tropical Australia. The perennial emergent sedge was found growing in acid waters (pH 2.45) and metal-rich tailings (SnAsCuPbZn). E. equisetina displayed a pronounced acid tolerance and tendency to exclude environmentally significant elements (Al, As, Cd, Ce, Co, Cu, Fe, La, Ni, Pb, Se, Th, U, Y, Zn) from its above-substrate biomass. This study demonstrates that geobotanical and biogeochemical examinations of wetland plants at abandoned mined lands of tropical areas can reveal pioneering, metal-excluding macrophytes. Such aquatic macrophytes are of potential use in the remediation of acid mine waters and sulfidic tailings and the reclamation of disturbed acid sulfate soils in subtropical and tropical regions. - Highlights: > In tropical Australia, Eleocharis equisetina grows in an acid mine tailings pond. > Eleocharis equisetina excludes environmentally significant elements from its biomass. > Inspections of equatorial mined lands can reveal metal-excluding aquatic macrophytes. > Such plants are of use in land and water remediation in tropical regions. - The metal-excluding aquatic macrophyte Eleocharis equisetina is of use in land and water remediation in tropical regions.

Fate of Deposited Nitrogen in Tropical Forests in Southern China

DEFF Research Database (Denmark)

Gurmesa, Geshere Abdisa

and denitrification from the ecosystem. Loss of N, in turn, has many negative consequences, including soil and surface water acidification, plant nutrient imbalances and related adverse effects on biological diversities. Increased atmospheric N deposition that is anticipated for tropical regions may further aggravate...... as N export in soil water in tropical forests. Total annual atmospheric deposition of N to the forest in the study period was 51 kg N ha-1yr-1. Nitrogen deposition was dominated by NH4-N due to intensive agricultural NH3 emissions in nearby areas. Nitrate dominated leaching loss from the soil...... after the last addition and by monitoring leaching of 15N in soil water on a monthly basis. The result showed that deposited N is effectively retained in plant and soil pools resembling and exceeding that observed for temperate forests. Furthermore, increased N input decreased the N retention efficiency...

Development of orodispersible films with selected Indonesian medicinal plant extracts

NARCIS (Netherlands)

Visser, Johanna; Eugresya, Gabriella; Hinrichs, Wouter; Tjandrawinata, Raymond; Avanti, Christina; Frijlink, H.W.; Woerdenbag, Herman

2017-01-01

This study focused on the incorporation into orodispersible films (ODFs) of the dried extracts of five selected Indonesian medicinal plants: Lagerstroemia speciosa (L.) Pers. (LS), Phyllanthus niruri L. (PN), Cinnamomum burmanii Blume (CB), Zingiber officinale Roscoe (ZO) and Phaleria macrocarpa

Land crabs as key drivers in tropical coastal forest recruitment

Science.gov (United States)

Lindquist, E.S.; Krauss, K.W.; Green, P.T.; O'Dowd, D. J.; Sherman, P.M.; Smith, T. J.

2009-01-01

Plant populations are regulated by a diverse assortment of abiotic and biotic factors that influence seed dispersal and viability, and seedling establishment and growth at the microsite. Rarely does one animal guild exert as significant an influence on different plant assemblages as land crabs. We review three tropical coastal ecosystems-mangroves, island maritime forests, and mainland coastal terrestrial forests-where land crabs directly influence forest composition by limiting tree establishment and recruitment. Land crabs differentially prey on seeds, propagules and seedlings along nutrient, chemical and physical environmental gradients. In all of these ecosystems, but especially mangroves, abiotic gradients are well studied, strong and influence plant species distributions. However, we suggest that crab predation has primacy over many of these environmental factors by acting as the first limiting factor of tropical tree recruitment to drive the potential structural and compositional organisation of coastal forests. We show that the influence of crabs varies relative to tidal gradient, shoreline distance, canopy position, time, season, tree species and fruiting periodicity. Crabs also facilitate forest growth and development through such activities as excavation of burrows, creation of soil mounds, aeration of soils, removal of leaf litter into burrows and creation of carbon-rich soil microhabitats. For all three systems, land crabs influence the distribution, density and size-class structure of tree populations. Indeed, crabs are among the major drivers of tree recruitment in tropical coastal forest ecosystems, and their conservation should be included in management plans of these forests. ?? 2009 Cambridge Philosophical Society.

Resource partitioning by evergreen and deciduous species in a tropical dry forest.

Science.gov (United States)

Álvarez-Yépiz, Juan C; Búrquez, Alberto; Martínez-Yrízar, Angelina; Teece, Mark; Yépez, Enrico A; Dovciak, Martin

2017-02-01

Niche differentiation can lead to coexistence of plant species by partitioning limiting resources. Light partitioning promotes niche differentiation in tropical humid forests, but it is unclear how niche partitioning occurs in tropical dry forests where both light and soil resources can be limiting. We studied the adult niche of four dominant evergreen (cycad, palm) and drought-deciduous (legume, oak) species co-occurring along environmental gradients. We analyzed light intensity and soil fertility effects on key functional traits related to plant carbon and water economy, how these traits determine species' functional strategies, and how these strategies relate to relative species abundance and spatial patterns. Light intensity was negatively associated with a key trait linked to plant water economy (leaf δ 13 C, a proxy for long-term water-use efficiency-WUE), while soil fertility was negatively associated with a key trait for plant carbon economy (LNC, leaf nitrogen content). Evergreens were highly sclerophyllous and displayed an efficient water economy but poor carbon economy, in agreement with a conservative resource-use strategy (i.e., high WUE but low LNC, photosynthetic rates and stature). Conversely, deciduous species, with an efficient carbon economy but poor water economy, exhibited an exploitative resource-use strategy (i.e., high LNC, photosynthetic rates and stature, but low WUE). Evergreen and deciduous species segregated spatially, particularly at fine-scales, as expected for species with different resource-use strategies. The efficient water economy of evergreens was related to their higher relative abundance, suggesting a functional advantage against drought-deciduous species in water-limited environments within seasonally dry tropical forests.

Psidium guajava 'Paluma' (the guava plant) as a new bio-indicator of ozone in the tropics

Energy Technology Data Exchange (ETDEWEB)

Furlan, C.M. [Departamento de Botanica, Instituto de Biociencias, Universidade de Sao Paulo, CP 11461, 05422-970 Sao Paulo, SP (Brazil)]. E-mail: furlancm@yahoo.com.br; Moraes, R.M. [Instituto de Botanica, SMA, CP 4005, 01061-970 Sao Paulo (Brazil); Bulbovas, P. [Departamento de Botanica, Instituto de Biociencias, Universidade de Sao Paulo, CP 11461, 05422-970 Sao Paulo, SP (Brazil); Domingos, M. [Instituto de Botanica, SMA, CP 4005, 01061-970 Sao Paulo (Brazil); Salatino, A. [Departamento de Botanica, Instituto de Biociencias, Universidade de Sao Paulo, CP 11461, 05422-970 Sao Paulo, SP (Brazil); Sanz, M.J. [Fundacion Centro de Estudios Ambientales del Mediterraneo, C/C. Darwin, 14, 46980 Paterna, Valencia (Spain)

2007-06-15

Psidium guajava 'Paluma' saplings were exposed to carbon filtered air (CF), ambient non-filtered air (NF), and ambient non-filtered air + 40 ppb ozone (NF + O{sub 3}) 8 h per day during two months. The AOT40 values at the end of the experiment were 48, 910 and 12 895 ppb h{sup -1}, respectively for the three treatments. After 5 days of exposure (AOT40 = 1497 ppb h{sup -1}), interveinal red stippling appeared in plants in the NF + O{sub 3} chamber. In the NF chamber, symptoms were observed only after 40 days of exposure (AOT40 = 880 ppb h{sup -1}). After 60 days, injured leaves per plant corresponded to 86% in NF + O{sub 3} and 25% in the NF treatment, and the average leaf area injured was 45% in NF + O{sub 3} and 5% in the NF treatment. The extent of leaf area injured (leaf injury index) was explained mainly by the accumulated exposure of ozone (r {sup 2} = 0.91; p < 0.05). - Psidium guajava 'Paluma', a tropical species widely used in Brazilian food industry, is a potential sensitive bio-indicator of ozone.

Optimal selection of major equipment in dual purpose plants

International Nuclear Information System (INIS)

Gabbrielli, E.

1981-01-01

Simulation of different operational conditions with the aid of a computer program is one of the best ways of assisting decision-makers in the selection of the most economic mix of equipment for a dual purpose plant. Using this approach this paper deals with the economic comparison of plants consisting of MSF desalinators and combustion gas or back pressure steam turbines coupled to low capacity electric power generators. The comparison is performed on the basis of the data made available by the OPTDIS computer program and the results are given in terms of yearly cost of production as the sum of capital, manpower, maintenance, fuel and chemical costs. (orig.)

Scatter hoarding of seeds confers survival advantages and disadvantages to large-seeded tropical plants at different life stages.

Directory of Open Access Journals (Sweden)

Erin K Kuprewicz

Full Text Available Scatter hoarding of seeds by animals contributes significantly to forest-level processes, including plant recruitment and forest community composition. However, the potential positive and negative effects of caching on seed survival, germination success, and seedling survival have rarely been assessed through experimental studies. Here, I tested the hypothesis that seed burial mimicking caches made by scatter hoarding Central American agoutis (Dasyprocta punctate enhances seed survival, germination, and growth by protecting seeds from seed predators and providing favorable microhabitats for germination. In a series of experiments, I used simulated agouti seed caches to assess how hoarding affects seed predation by ground-dwelling invertebrates and vertebrates for four plant species. I tracked germination and seedling growth of intact and beetle-infested seeds and, using exclosures, monitored the effects of mammals on seedling survival through time. All experiments were conducted over three years in a lowland wet forest in Costa Rica. The majority of hoarded palm seeds escaped predation by both invertebrates and vertebrates while exposed seeds suffered high levels of infestation and removal. Hoarding had no effect on infestation rates of D. panamensis, but burial negatively affected germination success by preventing endocarp dehiscence. Non-infested palm seeds had higher germination success and produced larger seedlings than infested seeds. Seedlings of A. alatum and I. deltoidea suffered high mortality by seed-eating mammals. Hoarding protected most seeds from predators and enhanced germination success (except for D. panamensis and seedling growth, although mammals killed many seedlings of two plant species; all seedling deaths were due to seed removal from the plant base. Using experimental caches, this study shows that scatter hoarding is beneficial to most seeds and may positively affect plant propagation in tropical forests, although

SRTM-DEM AND LANDSAT ETM+ DATA FOR MAPPING TROPICAL DRY FOREST COVER AND BIODIVERSITY ASSESSMENT IN NICARAGUA

OpenAIRE

Brett G. Dickson; Carol L. Chambers; Sarah M. Otterstrom; Suzanne E. Hagell; Steven E. Sesnie

2008-01-01

Tropical dry and deciduous forest comprises as much as 42% of the world’s tropical forests, but hasreceived far less attention than forest in wet tropical areas. Land use change threatens to greatly reducethe extent of dry forest that is known to contain high levels of plant and animal diversity. Forest fragmentationmay further endanger arboreal mammals that play principal role in the dispersal of large seeded fruits, plantcommunity assembly and diversity in these systems. Data on the spatial...

Resource stoichiometry and availability modulate species richness and biomass of tropical litter macro-invertebrates.

Science.gov (United States)

Jochum, Malte; Barnes, Andrew D; Weigelt, Patrick; Ott, David; Rembold, Katja; Farajallah, Achmad; Brose, Ulrich

2017-09-01

High biodiversity and biomass of soil communities are crucial for litter decomposition in terrestrial ecosystems such as tropical forests. However, the leaf litter that these communities consume is of particularly poor quality as indicated by elemental stoichiometry. The impact of resource quantity, quality and other habitat parameters on species richness and biomass of consumer communities is often studied in isolation, although much can be learned from simultaneously studying both community characteristics. Using a dataset of 780 macro-invertebrate consumer species across 32 sites in tropical lowland rain forest and agricultural systems on Sumatra, Indonesia, we investigated the effects of basal resource stoichiometry (C:X ratios of N, P, K, Ca, Mg, Na, S in local leaf litter), litter mass (basal resource quantity and habitat space), plant species richness (surrogate for litter habitat heterogeneity), and soil pH (acidity) on consumer species richness and biomass across different consumer groups (i.e. 3 feeding guilds and 10 selected taxonomic groups). In order to distinguish the most important predictors of consumer species richness and biomass, we applied a standardised model averaging approach investigating the effects of basal resource stoichiometry, litter mass, plant species richness and soil pH on both consumer community characteristics. This standardised approach enabled us to identify differences and similarities in the magnitude and importance of such effects on consumer species richness and biomass. Across consumer groups, we found litter mass to be the most important predictor of both species richness and biomass. Resource stoichiometry had a more pronounced impact on consumer species richness than on their biomass. As expected, taxonomic groups differed in which resource and habitat parameters (basal resource stoichiometry, litter mass, plant species richness and pH) were most important for modulating their community characteristics. The importance

Development of radiation processes wood-polymer composites based on tropical hardwoods

International Nuclear Information System (INIS)

Iya, V.K.; Majali, A.B.

1978-01-01

The wood-polymer composites based on tropical hardwoods were prepared with three monomer systems. Use of chlorinated paraffin oil as an additive imparted fire resistance to the composites and also brought down the gamma dose requirement for total polymerisation. A number of tropical hardwoods can be upgraded by radiation curing, but for cost optimisation, hardwoods with high improvement per unit polymer should be selected. (author)

Anthelmintic efficacy of five tropical native Australian plants against Haemonchus contortus and Trichostrongylus colubriformis in experimentally infected goats (Capra hircus).

Science.gov (United States)

Moreno, F C; Gordon, I J; Knox, M R; Summer, P M; Skerrat, L F; Benvenutti, M A; Saumell, C A

2012-06-08

The study of the anthelmintic properties of plants rich in plant secondary metabolites can provide ecologically sound methods for the treatment of parasites on grazing animals. The purpose of the present study was to evaluate the anthelmintic effect of five tropical native Australian plant species rich in plant secondary metabolites on adult Haemonchus contortus and Trichostrongylus colubriformis in experimentally infected goats. Thirty young, nematode-free goats were infected with 2500 H. contortus and 5000 T. colubriformis infective larvae thrice weekly for a week (day 1-7 of the experiment). On day 27 after first infection, the goats were allocated into six groups of five animals per group. From day 28 to day 35, fresh leaves from Acacia salicina, Acacia nilotica, Eucalyptus corymbia, Casuarina cunninghamiana and Eucalyptus drepanophylla were included in the goats diet. Five groups were offered leaves from one of these plant species and one group, the untreated control, received only the basal diet formulated with 20% Medicago sativa and 80% Avena sativa. Following plant material administration, the goats were monitored daily until day 40 and then slaughtered on day 41. Total faecal worm egg output, total production of larvae recovered from faecal cultures, total post-mortem worm burdens and the per capita fecundity of female worms were estimated. The toxicity of the plant species for the goats was measured by histopathological analyses of liver and kidney samples. Results showed that goats feeding on the plant material rich in plant secondary metabolites had significantly lower egg output compared to the control goats (P0.05), the per capita fecundity was significantly reduced by E. corymbia, A. nilotica and A. salicina (Pgoats can benefit from the short-term ingestion of plant secondary metabolites, which reduce the total faecal egg output and thus decrease the potential for re-infection from the pasture. Crown Copyright © 2012. Published by Elsevier B.V. All

Occupational hazard evaluation of working population in a select automotive industrial plant.

Science.gov (United States)

Wójcik, Alicja; Borzecki, Zdzisław; Kowalska, Edyta; Borzecki, Andrzej

2004-01-01

The research was conducted in the selected vehicle industry plant. Work conditions were assessed on the assembly line by measuring chemical and physical factors. Exposure to noise in the investigated plant exceeded the values of permissible standards. The pollution on the posts did not exceed the standards except singular concentrations. While assessing the values of chemical factors concentration, no toxicological danger was revealed in the investigated population. The work conditions of the investigated plant did not create the danger of professional diseases.

OPTIMAL WAVELENGTH SELECTION ON HYPERSPECTRAL DATA WITH FUSED LASSO FOR BIOMASS ESTIMATION OF TROPICAL RAIN FOREST

Directory of Open Access Journals (Sweden)

T. Takayama

2016-06-01

Full Text Available Above-ground biomass prediction of tropical rain forest using remote sensing data is of paramount importance to continuous large-area forest monitoring. Hyperspectral data can provide rich spectral information for the biomass prediction; however, the prediction accuracy is affected by a small-sample-size problem, which widely exists as overfitting in using high dimensional data where the number of training samples is smaller than the dimensionality of the samples due to limitation of require time, cost, and human resources for field surveys. A common approach to addressing this problem is reducing the dimensionality of dataset. Also, acquired hyperspectral data usually have low signal-to-noise ratio due to a narrow bandwidth and local or global shifts of peaks due to instrumental instability or small differences in considering practical measurement conditions. In this work, we propose a methodology based on fused lasso regression that select optimal bands for the biomass prediction model with encouraging sparsity and grouping, which solves the small-sample-size problem by the dimensionality reduction from the sparsity and the noise and peak shift problem by the grouping. The prediction model provided higher accuracy with root-mean-square error (RMSE of 66.16 t/ha in the cross-validation than other methods; multiple linear analysis, partial least squares regression, and lasso regression. Furthermore, fusion of spectral and spatial information derived from texture index increased the prediction accuracy with RMSE of 62.62 t/ha. This analysis proves efficiency of fused lasso and image texture in biomass estimation of tropical forests.

Determination of parameters influencing methylation and demethylation in tropical lakes in Brazil and Nicaragua

International Nuclear Information System (INIS)

Hylander, Lars D.; Ahlgren, Ingemar; Erikson, Rolf; Lantz, Peter; Toernblom, Erik; Forsberg, Bruce R.; Guimaraes, Jean R.D.; Meili, Markus; Montenegro Guillen, Salvador; Vammen, Katherine; Altamirano, Maximina; Zelaya, Argentina; Sarria Sacasa, Karla; Jimenez, Mario

2001-01-01

Increased awareness about the toxicity of mercury (Hg) has during the latest decades resulted in reduced Hg use in industrialised countries. Developing countries, on the contrary, have largely increased their anthropogenic Hg emissions caused by its use in gold mining, transfer of Hg emitting factories from developed countries, and increased burning of coal without appropriate flue gas cleaning. These increased emissions occur mainly in the tropics, where the fate of Hg is not well documented. The aim of the present study is to increase the knowledge about Hg levels and transformations in two tropical areas affected by anthropogenic Hg emissions - the Pantanal wetland in Brazil, housing gold miners using the amalgamation method, and Lake Xolotilan (Managua) in Nicaragua, where a chlor-alkali plant relocated from the USA has emitted much Hg. Actual Hg content in water, biota, and sediment will be determined by atomic fluorescence spectrophotometry and atomic absorption spectrophotometry. Mercury inethylation capacity in sediments and selected biota will be determined with in-situ incubations with 203 Hg and subsequent radiological measurements. Factors affecting the methylation and demethylation rates will be identified by varying environmental conditions such as pH, redox potential, conductivity, light, temperature, geochemical factors and population of bacteria. Sediment turnover will be studied by determining fallout cesium ( 137 Cs) in sediment profiles. The study is expected to increase the knowledge about Hg-transformations in the tropics and point out proper measures to reduce health hazards due to Hg-exposure. (author)

Studies in tropical teratology, 2nd Series, No. I

NARCIS (Netherlands)

Venema, H.J.

1937-01-01

Dr J. J. Smith is best known by his studies about Orchidaceae. But since 1904 he published regularly in collaboration with Dr J. C. Costerus in the ”Annales du Jardin Botanique de Buitenzorg“, the results of their researches in teratology of tropical plants. Some years ago, Dr J. J. Smith was so

Nectar plant selection by the Karner blue butterfly (Lycaeides melissa samuelis) at the Indiana Dunes National Lakeshore

Science.gov (United States)

Grundel, Ralph; Pavlovic, Noel B.; Sulzman, Christina L.

2000-01-01

The Karner blue butterfly, Lycaeides melissa samuelis, is an endangered species residing in savanna and barrens habitats in the Midwest and Northeast United States. To improve our understanding of nectar plant selection patterns by the Karner blue, we examined nectar plant choices made by 146 butterflies. Within observation areas of 2-m radius butterflies usually chose the nectar species with the greatest total number of flowers or flowering heads. This suggests that the Karner blue is opportunistic in selecting nectar plants. However, certain nectar species, including Arabis lyrata, Coreopsis lanceolata, Melilotus alba and Rubus flagellaris, were selected in a significant majority of cases when other nectar species were available nearby. At least in the case of R. flagellaris, this preference was not directly related to the species' local flower abundance. In a significant majority of cases (77.5%) adult Karner blues selected nectar plant species with yellow or white flowers over species with other-colored flowers. Comparison of nectar plant selections at Indiana Dunes National Lakeshore to selections from Michigan and Wisconsin suggests that the Karner blue most frequently chooses a suite of nectar plant species that includes A. lyrata, C. lanceolata, Euphorbia corollata, M. alba, Monarda punctata, Potentilla simplex, Rubus spp., Solidago speciosa and, perhaps, Asclepias tuberosa and Helianthus divaricatus. This suite includes plant species that readily flower in the sun and others that readily flower in the shade, an important consideration since Karner blues often move across the sun-shade interface.

Antioxidant Capacity of Selected Plant Extracts and Their Essential Oils

Directory of Open Access Journals (Sweden)

Charalampos Proestos

2013-01-01

Full Text Available The main objective of this study was the screening of some selected aromatic plants very popular in Greece, with respect to their total phenolic content, antioxidant capacity, reducing activity, and oxidative stability. All plants were extracted with the conventional method, reflux with methanol. The essential oils of the plants were also analyzed for their antioxidant properties. The total phenolic content was determined by the Folin-Ciocalteu method using gallic acid as the standard, while the phenolic substances were identified and quantified by High Performance Liquid Chromatography (HPLC coupled with a multi-wavelength ultraviolet-visible (UV-vis detector. The antioxidant capacity of the plant extracts was measured by their ability to scavenge free radicals such as (a DPPH (2,2-diphenyl-1-picrylhydrazyl and, (b ABTS (2,2′-azinobis-(3-ethylbenzothiaziline-6- sulfonate. The Folin-Ciocalteu method proved the existence of antioxidants in the aromatic plant extracts. Taking into account the results of the DPPH and ABTS methods, the free radical scavenging capacity was confirmed. Eventually, all plants exhibited low but noticeable protection levels against lipid oxidation, as determined by the Rancimat test.

Screening of selected indigenous plants of Cambodia for antiplasmodial activity.

Science.gov (United States)

Hout, Sotheara; Chea, Aun; Bun, Sok-Siya; Elias, Riad; Gasquet, Monique; Timon-David, Pierre; Balansard, Guy; Azas, Nadine

2006-08-11

The in vitro antiplasmodial activity of 117 aqueous, methanol and dichloromethane extracts derived from different parts of 28 indigenous wild plant species was studied. These plants are commonly used in Cambodian traditional medicine. The plant extracts were tested for in vitro activity against a chloroquine resistant Plasmodium falciparum strain (W2). Nine extracts were moderately active with IC(50) values ranging between 5 and 10 microg/ml, 17 extracts were active with IC(50) values ranging between 1 and 5 microg/ml. These 26 extracts derived from eight plants belong to six families. The most active extracts were dichloromethane and came from Stephania rotunda and Brucea javanica with IC(50) values of 1 microg/ml and a selectivity index > or = 25. It is interesting to note that some aqueous extracts were as active as dichloromethane extracts especially aqueous extracts of Stephania rotunda, Brucea javanica, Phyllanthus urinaria and Eurycoma longifolia with IC(50) values of uses of these plants for the treatment of malaria and/or fever. In this study, we report the antiplasmodial potential activity of eight plant species from Cambodia. Among them four are tested for the first time.

SCREENING OF PHYTOCHEMICALS AND IMMUNOMODULATORY POTENTIAL OF A MEDICINAL PLANT, CINNAMOMUM TAMALA

OpenAIRE

P. Jeyasree* and P. Dasarathan

2012-01-01

Cinnamomum tamala is found in tropical and sub-tropical Himalayas and in some other places. Phytochemical screening of the plant extracts were done to screen their active constituents. Antimicrobial activity of this plant extract was investigated by Kirby-Bayer methodology against four pathogenic organisms: K. Pneumonae,E. coli, S. aureus, and P.aeroginosa. The plant Butanol extract showed inhibitory activity against all the tested organisms and it has enhanced immunomodulatory activity also....

Genotypic character relationship and phenotypic path coefficient analysis in chili pepper genotypes grown under tropical condition.

Science.gov (United States)

Usman, Magaji G; Rafii, Mohd Y; Martini, Mohammad Y; Oladosu, Yusuff; Kashiani, Pedram

2017-03-01

Studies on genotypic and phenotypic correlations among characters of crop plants are useful in planning, evaluating and setting selection criteria for the desired characters in a breeding program. The present study aimed to estimate the phenotypic correlation coefficients among yield and yield attributed characters and to work out the direct and indirect effects of yield-related characters on yield per plant using path coefficient analysis. Twenty-six genotypes of chili pepper were laid out in a randomized complete block design with three replications. Yield per plant showed positive and highly significant (P ≤ 0.01) correlations with most of the characters studied at both the phenotypic and genotypic levels. By contrast, disease incidence and days to flowering showed a significant negative association with yield. Fruit weight and number of fruits exerted positive direct effect on yield and also had a positive and significant (P ≤ 0.01) correlation with yield per plant. However, fruit length showed a low negative direct effect with a strong and positive indirect effect through fruit weight on yield and had a positive and significant association with yield. Longer fruits, heavy fruits and a high number of fruits are variables that are related to higher yields of chili pepper under tropical conditions and hence could be used as a reliable indicator in indirect selection for yield. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Lack of a response of the sub-tropical rodent (Saccostomus ...

African Journals Online (AJOL)

1998-03-09

Mar 9, 1998 ... A potential strategy for southern African small mammals to maximise reproductive success is to cue breeding activity to rainfall and subsequent vegetative growth via a secondary plant compound such as 6-methoxyben- zoxazolinone (6MBOA). This study investigated whether the sub-tropical rodent ...

Nutritional potentials of some tropical vegetable leaf meals ...

African Journals Online (AJOL)

Three tropical vegetable species (Talium triangulare, Amaranthus cruentus and Telfairia occidentalis) were selected based on their availability and agronomic desirability. The freshly harvested vegetable leaves were subjected to 2 processing techniques (shredding and sundrying) before milling into the vegetable leaf ...

Deadwood biomass: an underestimated carbon stock in degraded tropical forests?

Science.gov (United States)

Pfeifer, Marion; Lefebvre, Veronique; Turner, Edgar; Cusack, Jeremy; Khoo, MinSheng; Chey, Vun K.; Peni, Maria; Ewers, Robert M.

2015-04-01

Despite a large increase in the area of selectively logged tropical forest worldwide, the carbon stored in deadwood across a tropical forest degradation gradient at the landscape scale remains poorly documented. Many carbon stock studies have either focused exclusively on live standing biomass or have been carried out in primary forests that are unaffected by logging, despite the fact that coarse woody debris (deadwood with ≥10 cm diameter) can contain significant portions of a forest’s carbon stock. We used a field-based assessment to quantify how the relative contribution of deadwood to total above-ground carbon stock changes across a disturbance gradient, from unlogged old-growth forest to severely degraded twice-logged forest, to oil palm plantation. We measured in 193 vegetation plots (25 × 25 m), equating to a survey area of >12 ha of tropical humid forest located within the Stability of Altered Forest Ecosystems Project area, in Sabah, Malaysia. Our results indicate that significant amounts of carbon are stored in deadwood across forest stands. Live tree carbon storage decreased exponentially with increasing forest degradation 7-10 years after logging while deadwood accounted for >50% of above-ground carbon stocks in salvage-logged forest stands, more than twice the proportion commonly assumed in the literature. This carbon will be released as decomposition proceeds. Given the high rates of deforestation and degradation presently occurring in Southeast Asia, our findings have important implications for the calculation of current carbon stocks and sources as a result of human-modification of tropical forests. Assuming similar patterns are prevalent throughout the tropics, our data may indicate a significant global challenge to calculating global carbon fluxes, as selectively-logged forests now represent more than one third of all standing tropical humid forests worldwide.

Selective pruning in pineapple plants as means to reduce heterogeneity in fruit quality

NARCIS (Netherlands)

Fassinou Hotegni, V.N.; Lommen, W.J.M.; Struik, P.C.; Agbossou, E.K.

2015-01-01

Heterogeneity in fruit quality (size and taste) is a major problem in pineapple production chains. The possibilities were investigated of reducing the heterogeneity in pineapple in the field by pruning slips on selected plants, in order to promote the fruit growth on these plants. Slips are side

Notes on the Vegetation of the Fast-flowing Streams in Peninsular Thailand, the Tropical Mainland of South East Asia

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Milica Stankovic

2013-12-01

Full Text Available The species composition and structure of the plant communities along and in the fast-flowing streams on different bedrock types of the tropical mainland South-East Asia were investigated. The study was carried out in Peninsular Thailand, on the Nakhon Si Thammarat mountain range. A total number of 14 plots were placed within the five selected streams where vascular plants species had been collected, starting from November 2010 until July 2012. The estimation of the species was calculated by computer program EstimateS, and in order to distinguish plant communities, a cluster analysis was performed. A total number of 109 species of vascular plants has been recorded, with 59 species in the granite and 60 in the calcareous bedrock streams. There were four types of plant communities that had were categorized; of which three types occurred in the granitic bedrock streams and the other could be seen exclusively in the calcareous bedrock. It is convinced that the types of the bedrock as well as the topographic features of the streams might have major impact on the characterization of the plant communities.

The influence of plant spacing in the early stages of selection of rice (Oryza sativa L.) varieties

Energy Technology Data Exchange (ETDEWEB)

Torró, I.; Bretó, P.; García-Yzaguirre, A.

2016-11-01

The cultural practices of the early generations in a pedigree breeding programme may influence its success. The main objective of this study was to compare two selection environments in rice: Widely spaced planting in the field and dense planting in concrete basins. Both methods had yielded commercial varieties in the past. Two F2 populations (J and MS), derived from two crosses sharing the same female parent, were transplanted to both environments. Phenotypic traits were evaluated and their narrow sense heritabilities (h2) estimated in the F3 and in the F4 progenies of selected plants, all grown in the field. Growth potential was more apparent in the field for most traits, especially those related to yield, but broad sense heritabilities were higher in the basins for ten traits, being higher in the field for the other five. In population F2MS, field selection resulted in F3 plants which retained a higher tillering ability than those derived from basins selection. Most traits showed low h2 values: Additive variance was only relevant in panicle length (in both populations), plant height and mean panicle weight (in the J population). However, response to one generation of selection (from F3 to F4) also showed fixable variation in panicle number. In addition, this selection reduced plant height, increased culm diameter and internode length (in both populations), and improved pulling resistance (against lodging) in population J. It may be concluded that both practices can be used for selection in the F2, although different responses might be expected in yield related traits. (Author)

Current trends of tropical fruit waste utilization.

Science.gov (United States)

Cheok, Choon Yoong; Mohd Adzahan, Noranizan; Abdul Rahman, Russly; Zainal Abedin, Nur Hanani; Hussain, Norhayati; Sulaiman, Rabiha; Chong, Gun Hean

2018-02-11

Recent rapid growth of the world's population has increased food demands. This phenomenon poses a great challenge for food manufacturers in maximizing the existing food or plant resources. Nowadays, the recovery of health benefit bioactive compounds from fruit wastes is a research trend not only to help minimize the waste burden, but also to meet the intensive demand from the public for phenolic compounds which are believed to have protective effects against chronic diseases. This review is focused on polyphenolic compounds recovery from tropical fruit wastes and its current trend of utilization. The tropical fruit wastes include in discussion are durian (Durio zibethinus), mangosteen (Garcinia mangostana L.), rambutan (Nephelium lappaceum), mango (Mangifera indica L.), jackfruit (Artocarpus heterophyllus), papaya (Carica papaya), passion fruit (Passiflora edulis), dragon fruit (Hylocereus spp), and pineapple (Ananas comosus). Highlights of bioactive compounds in different parts of a tropical fruit are targeted primarily for food industries as pragmatic references to create novel innovative health enhancement food products. This information is intended to inspire further research ideas in areas that are still under-explored and for food processing manufacturers who would like to minimize wastes as the norm of present day industry (design) objective.

Potentialities of line planting technique in rehabilitation of logged over area referred to species diversity, growth and soil quality

Directory of Open Access Journals (Sweden)

PRIJANTO PAMOENGKAS

2010-01-01

Full Text Available Pamoengkas P (2010 Potentialities of line planting technique in rehabilitation of logged over area referred to species diversity, growth and soil quality. Biodiversitas 11: 34-39. Human interventions in the utilization of tropical forest resources are experiencing unanticipated consequences. The selective logging practices generally cause considerable damage to vegetation and the soil surface. It is supposed that soil condition and vegetation growth rate are deteriorated and reduced. Therefore, scientist strongly argue that the only way to achieve sustainability of Indonesian natural forest will require that the production natural forest is managed through methods that are acceptable from the perspective of environment as well as timber production. This means that there will be a strong need and incentive for methods and innovative technology. For more than two decades, tropical rainforest in Indonesia have been managed intensively under the Indonesian selective cutting (TPI and later on by the Indonesian selective cutting and replanting (TPTI and then, selective cutting and line planting (TPTJ system. TPTJ, as one example of selective cutting, recently become a proper alternative should be taken into consideration in the management of production natural forest in Indonesia by planting dipterocarp species in line. In this system, planting line (width 3 m and intermediate line (width 17 m are made alternately. The initial width of line is 3 m and to be expanded until 10 m within 5 years to introduce more light. The objective of this research was to assess growth and soil quality of TPTJ system. The object of research was TPTJ plot of various ages from 1 year to 7 years. For achieving the objective, 14 sample plots measuring 200 m x 200 m each, were laid out at research plots. The result showed that growth respond of Shorea leprosula toward the width of planting line was better comparing to Shorea parvifolia, but generally from this growth

Leaf litter arthropod responses to tropical forest restoration.

Science.gov (United States)

Cole, Rebecca J; Holl, Karen D; Zahawi, Rakan A; Wickey, Philipp; Townsend, Alan R

2016-08-01

Soil and litter arthropods represent a large proportion of tropical biodiversity and perform important ecosystem functions, but little is known about the efficacy of different tropical forest restoration strategies in facilitating their recovery in degraded habitats. We sampled arthropods in four 7- to 8-year-old restoration treatments and in nearby reference forests. Sampling was conducted during the wet and dry seasons using extractions from litter and pitfall samples. Restoration treatments were replicated in 50 × 50-m plots in four former pasture sites in southern Costa Rica: plantation - trees planted throughout the plot; applied nucleation/islands - trees planted in patches of different sizes; and natural regeneration - no tree planting. Arthropod abundance, measures of richness and diversity, and a number of functional groups were greater in the island treatment than in natural regeneration or plantation treatments and, in many cases, were similar to reference forest. Litter and pitfall morphospecies and functional group composition in all three restoration treatments were significantly different than reference sites, but island and plantation treatments showed more recovery than natural regeneration. Abundance and functional group diversity showed a much greater degree of recovery than community composition. Synthesis and applications: The less resource-intensive restoration strategy of planting tree islands was more effective than tree plantations in restoring arthropod abundance, richness, and functional diversity. None of the restoration strategies, however, resulted in similar community composition as reference forest after 8 years of recovery, highlighting the slow rate of recovery of arthropod communities after disturbance, and underscoring the importance of conservation of remnant forests in fragmented landscapes.

Diversity of Ammonia Oxidizing Archaea in Tropical Compost Systems

Directory of Open Access Journals (Sweden)

Vidya eDe Gannes

2012-07-01

Full Text Available Composting is widely used to transform waste materials into valuable agricultural products. In the tropics, large quantities of agricultural wastes could be potentially useful in agriculture after composting. However, while microbiological processes of composts in general are well established, relatively little is known about microbial communities that may be unique to these in tropical systems, particularly nitrifiers. The recent discovery of ammonia oxidizing archaea (AOA has changed the paradigm of nitrification being initiated solely by ammonia oxidizing bacteria. In the present study, AOA abundance and diversity was examined in composts produced from combinations of plant waste materials common in tropical agriculture (rice straw, sugar cane bagasse, coffee hulls, which were mixed with either cow- or sheep-manure. The objective was to determine how AOA abundance and diversity varied as a function of compost system and time, the latter being a contrast between the start of the compost process (mesophilic phase and the finished product (mature phase. The results showed that AOA were relatively abundant in composts of tropical agricultural wastes, and significantly more so than were the ammonia-oxidizing bacteria. Furthermore, while the AOA communities in the composts were predominatly group I.1b, the communities were diverse and exhibited structures that diverged between compost types and phases. These patterns could be taken as indicators of the ecophysiological diversity in the soil AOA (groub I.1b, in that significantly different AOA communties developed when exposed to varying physico-chemical environments. Nitrification patterns and levels differed in the composts which, for the mature material, could have signifcant effects on its performanc as a plant growth medium. Thus, it will also be important to determine the association of AOA (and diversity in their communities with nitrification in these systems.

Tropical vegetation evidence for rapid sea level changes associated with Heinrich Events

Energy Technology Data Exchange (ETDEWEB)

Gonzalez, Catalina; Dupont, Lydie M, E-mail: catalina@uni-bremen.d, E-mail: dupont@uni-bremen.d [MARUM - Centre for Marine Environmental Sciences, University of Bremen, Leobener Strasse, D-28359 Germany (Germany)

2010-03-15

A Cariaco Basin pollen record shows the development of tropical salt marshes during marine isotope stage 3. Rapid and abrupt expansions of salt marsh vegetation in tropical South America are associated with north Atlantic Heinrich Events stadials (HE-stadials). Intervals of salt marsh expansion have an internal structure, which consists of a recurrent alternation of species that starts with pollen increments of Chenopodiaceae, that are followed by increments of grasses, and subsequently by increments of Cyperaceae. This pattern suggests a successional process that is determined by the close relationship between sea-level and plant community dynamics. The salt tolerant Chenopodiaceae, indicate hypersaline intertidal environments, which were most likely promoted by extremely dry atmospheric conditions. Rapid sea-level rise characterizes the onset of HE-stadials, causing the continued recruitment of pioneer species, which are the only ones tolerating rapid rates of disturbance. Once sea-level rise decelerates, marsh plants are able to trap and stabilize sediments, favouring the establishment of more competitive species. These results add to the scarce knowledge on the dynamics of tropical salt marsh ecosystems, and provide independent paleoclimatic evidence on sea-level changes following Antarctic climate variability.

Soil macrofauna and litter nutrients in three tropical tree plantations on a disturbed site in Puerto Rico.

Science.gov (United States)

Matthew W. Warren; Xiaoming Zou

2002-01-01

Tree plantations are increasingly common in tropical landscapes due to their multiple uses. Plantations vary in structure and composition, and these variations may alter soil fauna communities. Recent studies have demonstrated the important role of soil fauna in the regulation of plant litter decomposition in the tropics. However, little is known about how plantation...

Specialization of mutualistic interaction networks decreases toward tropical latitudes

DEFF Research Database (Denmark)

Schleuning, M.; Fründ, J.; Klein, A.-M.

2012-01-01

that current conditions have a stronger effect on biotic specialization than historical community stability. Biotic specialization decreased with increasing local and regional plant diversity. This suggests that high specialization of mutualistic interactions is a response of pollinators and seed dispersers......] or differences in plant diversity [10, 11]. Thus, the direction of the latitudinal specialization gradient remains contentious. With an unprecedented global data set, we investigated how biotic specialization between plants and animal pollinators or seed dispersers is associated with latitude, past...... and contemporary climate, and plant diversity. We show that in contrast to expectation, biotic specialization of mutualistic networks is significantly lower at tropical than at temperate latitudes. Specialization was more closely related to contemporary climate than to past climate stability, suggesting...

Staying cool: preadaptation to temperate climates required for colonising tropical alpine-like environments

Directory of Open Access Journals (Sweden)

Berit Gehrke

2018-04-01

Full Text Available Plant species tend to retain their ancestral ecology, responding to temporal, geographic and climatic changes by tracking suitable habitats rather than adapting to novel conditions. Nevertheless, transitions into different environments or biomes still seem to be common. Especially intriguing are the tropical alpine-like areas found on only the highest mountainous regions surrounded by tropical environments. Tropical mountains are hotspots of biodiversity, often with striking degrees of endemism at higher elevations. On these mountains, steep environmental gradients and high habitat heterogeneity within small spaces coincide with astounding species diversity of great conservation value. The analysis presented here shows that the importance of in situ speciation in tropical alpine-like areas has been underestimated. Additionally and contrary to widely held opinion, the impact of dispersal from other regions with alpine-like environments is relatively minor compared to that of immigration from other biomes with a temperate (but not alpine-like climate. This suggests that establishment in tropical alpine-like regions is favoured by preadaptation to a temperate, especially aseasonal, freezing regime such as the cool temperate climate regions in the Tropics. Furthermore, emigration out of an alpine-like environment is generally rare, suggesting that alpine-like environments – at least tropical ones – are species sinks.

Road-networks, a practical indicator of human impacts on biodiversity in Tropical forests

International Nuclear Information System (INIS)

Hosaka, T; Yamada, T; Okuda, T

2014-01-01

Tropical forests sustain the most diverse plants and animals in the world, but are also being lost most rapidly. Rapid assessment and monitoring using remote sensing on biodiversity of tropical forests is needed to predict and evaluate biodiversity loss by human activities. Identification of reliable indicators of forest biodiversity and/or its loss is an urgent issue. In the present paper, we propose the density of road networks in tropical forests can be a good and practical indicator of human impacts on biodiversity in tropical forests through reviewing papers and introducing our preliminary survey in peninsular Malaysia. Many previous studies suggest a strong negative impact of forest roads on biodiversity in tropical rainforests since they changes microclimate, soil properties, drainage patterns, canopy openness and forest accessibility. Moreover, our preliminary survey also showed that even a narrow logging road (6 m wide) significantly lowered abundance of dung beetles (well-known bio-indicator in biodiversity survey in tropical forests) near the road. Since these road networks are readily to be detected with remote sensing approach such as aerial photographs and Lider, regulation and monitoring of the road networks using remote sensing techniques is a key to slow down the rate of biodiversity loss due to forest degradation in tropical forests

Road-networks, a practical indicator of human impacts on biodiversity in Tropical forests

Science.gov (United States)

Hosaka, T.; Yamada, T.; Okuda, T.

2014-02-01

Tropical forests sustain the most diverse plants and animals in the world, but are also being lost most rapidly. Rapid assessment and monitoring using remote sensing on biodiversity of tropical forests is needed to predict and evaluate biodiversity loss by human activities. Identification of reliable indicators of forest biodiversity and/or its loss is an urgent issue. In the present paper, we propose the density of road networks in tropical forests can be a good and practical indicator of human impacts on biodiversity in tropical forests through reviewing papers and introducing our preliminary survey in peninsular Malaysia. Many previous studies suggest a strong negative impact of forest roads on biodiversity in tropical rainforests since they changes microclimate, soil properties, drainage patterns, canopy openness and forest accessibility. Moreover, our preliminary survey also showed that even a narrow logging road (6 m wide) significantly lowered abundance of dung beetles (well-known bio-indicator in biodiversity survey in tropical forests) near the road. Since these road networks are readily to be detected with remote sensing approach such as aerial photographs and Lider, regulation and monitoring of the road networks using remote sensing techniques is a key to slow down the rate of biodiversity loss due to forest degradation in tropical forests.

Selection of mercury accumulator plants for gold mine tailing contaminated soils

Directory of Open Access Journals (Sweden)

N Muddarisna

2015-04-01

Full Text Available Phytoremediation, which is more efficient with less side effects than conventional physical and chemical methods, is increasing in popularity as a remediation system. This paper provides a brief overview of developments in research and application of phytoremediation of soil contaminated with gold mine tailings containing mercury. Lindernia crustacea L., Digitaria radicosa Presl. Miq., Zingiber purpurium L, Paspalum conjugatum Berg., Cyperus kyllingia Endl., and Caladium bicolor Vent., that were selected for this study were planted in the planting media consisting of soil (70% and tailings (30% for 9 weeks. The results showed that after 9 weeks of planting, Paspalum conjugatum had growth rate, biomass production, Hg accumulation, and ratio of shoot Hg : root Hg higher than those of other plant species tested, both in the media consisted of amalgamation and cyanidation tailings. It can thus be concluded that Paspalum conjugatum is potential plant species for remediating mercury-contaminated soil.

Drought tolerant tropical maize (Zea mays L.) developed through ...

African Journals Online (AJOL)

Tuoyo Aghomotsegin

2016-10-26

Oct 26, 2016 ... Seeds of the tropical maize inbred line CML216 were obtained from the International ... Infection, co-cultivation, resting, selection and maturation media ...... abscisic acid concentration does not induce kernel abortion in field-.

Nutritional and cultural aspects of plant species selection for a controlled ecological life support system

Science.gov (United States)

Hoff, J. E.; Howe, J. M.; Mitchell, C. A.

1982-01-01

The feasibility of using higher plants in a controlled ecological life support system is discussed. Aspects of this system considered important in the use of higher plants include: limited energy, space, and mass, and problems relating to cultivation and management of plants, food processing, the psychological impact of vegetarian diets, and plant propagation. A total of 115 higher plant species are compared based on 21 selection criteria.

OPTIMIZATION OF DIRECT COMPRESSION TABLET FORMULATIONS FOR USE IN TROPICAL COUNTRIES

NARCIS (Netherlands)

Bos, C. E.; BOLHUIS, G. K.; LERK, C. F.; de Boer, J. H.; DUINEVELD, C. A. A.; Smilde, A. K.; Doornbos, D. A.

1991-01-01

With the aid of a combined mixture- and factorial- design, 2 standard tablet formulations were selected suitable for use in tropical countries. The formulations were based on native ingredients or ingredients that are available worldwide. The selection of the standard formulations was based on both

Productivity of selected plant species adapted to arid regions. [Crassulacean metabolizing plants; Agave deserti and Ferocactus acanthodes

Energy Technology Data Exchange (ETDEWEB)

Nobel, P.S.

1980-01-01

The biomass potential of selected arid region species for alcohol production merits careful consideration. The basis for this interest is the current low agronomic use of arid lands and the potential productivity of certain species adapted to these lands. Plants displaying Crassulacean acid metabolism (CAM) are particularly interesting with reference to biomass for fuel in regions with low rainfall, because plants with this photosynthetic process are strikingly efficient in water requirements. For CAM plants, CO/sub 2/ fixation occurs primarily at night, when tissue surface temperature and hence transpirational water loss is less than daytime values. For Agave deserti in the Sonoran desert, the water-use efficiency (mass of CO/sub 2/ fixed/mass of water transpired) over an entire year is an order of magnitude or more larger than for C-3 and C-4 plants. This indicates how well adapted CAM species are to arid regions. The potential productivity per unit land area of CAM plants is fairly substantial and, therefore, of considerable economic interest for arid areas where growth of agricultural plants is minimal.

Insects associated with tropical foliage produced in the coffee growing region of Colombia

Directory of Open Access Journals (Sweden)

Luis F. Aristizábal

2013-09-01

Full Text Available We conducted a survey of insects and pest management practices on 34 farms growing ornamental tropical foliage plants in the central coffee region of Colombia over two years. Tropical foliage provided habitat for a diverse range of insects. In total, phytophagous or detritivorous insects from six orders, 40 families and 62 genera were collected. The most common were Hemiptera (29 genera from 16 families, followed by Coleoptera (17 genera from 4 families, Diptera (5 genera from 5 families, Lepidoptera (5 genera from 4 families, Hymenoptera (3 genera from 2 families and Orthoptera (2 genera from 2 families. The most common phytophagous species were leaf cutting ants (Atta and Acromyrmex spp., leaf beetles (Chrysomelidae, leafhoppers (Cicadellidae, stinkbugs (Pentatomidae, squash bugs (Coreidae, tree hoppers (Membracidae and plant hoppers (Fulgoridae. Beneficial insects identified from tropical foliage included predators and parasitoids amongst 5 orders, 12 families and 22 genera. The most abundant were predators among the Coccinellidae, Chrysopidae, Reduviidae, Lycidae and Formicidae but only low numbers of parasitoids (Ichneumonidae, Braconidae and Tachinidae were collected. A pest management questionnaire given to growers revealed a preponderance of reliance on broad spectrum insecticides with a smaller number of growers (approximately one third also using some biological control methods. Our survey contributes basic information regarding diversity of Neotropical insects associated with ornamental foliage plants.

on the use of selected aquatic plants in tracing of some heavy metal pollutants

International Nuclear Information System (INIS)

Hammad, D.M.; Tawfik, T.A.

2004-01-01

three aquatic macrophyte plants namely; Cyperus Rotundus (emergent plant), Phragmits Australis (emergent plant) and Echhornia crassipes (floating plant) were selected to measure their ability for uptake of heavy metal pollutants from their ambient environments and to decide the possibility of using such plants in practical applications of water and sediment purity monitoring and decontamination . these plants with the corresponding water and sediment samples were collected from El-rayah El-menoufy (comparable site), near El- kanater El- khayria which receives its water directly from the River Nile (Dommietta branch) and from two drains namely. El remal drain (sewage drain), which receives its water from Abu-rawash waste water treatment plant and El-tibeen drain (mixed agricultural and industrial drain), located at the right bank of the River Nile and surrounded by huge industrial factories and receives its water from El-khashab canal. the water, sediment and plant samples collected from the selected areas were analyzed for anions, cations and heavy metal contents. studying and comparing the accumulative capacity of the emergent and floating plants to measure their ability in phytoremediatic applications and heavy metal pollution studies were performed . the correlations between the heavy metal concentrations in plants and in their ambient environments were calculated and the potential of the examined plants for pollution monitoring was estimated . in addition, the natural radioactivity of the environmental sediments was evaluated for K-40, Th -232 and Ra-226. the results obtained were compared with the international reference values

Pervasive phosphorus limitation of tree species but not communities in tropical forests

Science.gov (United States)

Turner, Benjamin L.; Brenes-Arguedas, Tania; Condit, Richard

2018-03-01

Phosphorus availability is widely assumed to limit primary productivity in tropical forests, but support for this paradigm is equivocal. Although biogeochemical theory predicts that phosphorus limitation should be prevalent on old, strongly weathered soils, experimental manipulations have failed to detect a consistent response to phosphorus addition in species-rich lowland tropical forests. Here we show, by quantifying the growth of 541 tropical tree species across a steep natural phosphorus gradient in Panama, that phosphorus limitation is widespread at the level of individual species and strengthens markedly below a threshold of two parts per million exchangeable soil phosphate. However, this pervasive species-specific phosphorus limitation does not translate into a community-wide response, because some species grow rapidly on infertile soils despite extremely low phosphorus availability. These results redefine our understanding of nutrient limitation in diverse plant communities and have important implications for attempts to predict the response of tropical forests to environmental change.

Selective autophagy of non-ubiquitylated targets in plants: looking for cognate receptor/adaptor proteins

Directory of Open Access Journals (Sweden)

Vasko eVeljanovski

2014-06-01

Full Text Available Cellular homeostasis is essential for the physiology of eukaryotic cells. Eukaryotic cells, including plant cells, utilize two main pathways to adjust the level of cytoplasmic components, namely the proteasomal and the lysosomal/vacuolar pathways. Macroautophagy is a lysosomal/vacuolar pathway which, until recently, was thought to be non-specific and a bulk degradation process. However, selective autophagy which can be activated in the cell under various physiological conditions, involves the specific degradation of defined macromolecules or organelles by a conserved molecular mechanism. For this process to be efficient, the mechanisms underlying the recognition and selection of the cargo to be engulfed by the double-membrane autophagosome are critical, and not yet well understood. Ubiquitin (poly-ubiquitin conjugation to the target appears to be a conserved ligand mechanism in many types of selective autophagy, and defined receptors/adaptors recognizing and regulating the autophagosomal capture of the ubiquitylated target have been characterized. However, non-proteinaceous and non-ubiquitylated cargoes are also selectively degraded by this pathway. This ubiquitin-independent selective autophagic pathway also involves receptor and/or adaptor proteins linking the cargo to the autophagic machinery. Some of these receptor/adaptor proteins including accessory autophagy-related (Atg and non-Atg proteins have been described in yeast and animal cells but not yet in plants. In this review we discuss the ubiquitin-independent cargo selection mechanisms in selective autophagy degradation of organelles and macromolecules and speculate on potential plant receptor/adaptor proteins.

Wind data for wind driven plant. [site selection for optimal performance

Science.gov (United States)

Stodhart, A. H.

1973-01-01

Simple, averaged wind velocity data provide information on energy availability, facilitate generator site selection and enable appropriate operating ranges to be established for windpowered plants. They also provide a basis for the prediction of extreme wind speeds.

Nuclear power plant site selection: a case study

International Nuclear Information System (INIS)

Lugasi, Y.; Mehrez, A.; Sinuany-Stern, Z.

1985-01-01

Selecting the site for a nuclear power plant involves the evaluation of numerous criteria and the professional judgment of various experts. The Israel Atomic Energy Commission has been concerned with the problem of selecting a site for a nuclear power station. Previous studies have been performed by the commission to identify potential sites. There were initial screenings where potential sites were chosen according to various minimal criteria and international standards. Only sites that met all the criteria were chosen. A study was made to find the most preferred site among the potential sites that met all the criteria. Two mathematical approaches were used: Keeney's multiattribute utility function and Saaty's eigenvalue prioritization technique. Both models ranked the same site as the most desirable; however, the models differed in their ranking of the other sites

On site selection of thermoelectric power plants in polluted environment

International Nuclear Information System (INIS)

Gheorghe, A.V.

1992-01-01

This paper discusses the environmental impact of combined heat-power plants. The selection of the site of these plants depends on the spatial distribution law of pollutants and their chemical interaction with environment. The solutions of a diffusion equation describing a system of chemically interacting pollutants are given and discussed. The environmental impacts are described in terms of wind and atmosphere stability, effective and built stack height and the source distance parameters. The optimal constructive solutions are judged upon the concentrations of sulfur and nitrogen oxides at the ground level which must be kept under the maximum admissible limit. (author). 8 figs

Selection and adaptation in irradiated plant and animal populations: a review

International Nuclear Information System (INIS)

Hart, D.R.

1981-03-01

Available literature on the effects of ionizing radiation on mutation rates, variability and adaptive responses to selection in exposed plant and animal populations is reviewed. Accumulated variability, and hence potential selection differentials, may be increased by many times due to induced mutation. The radiation dose that maximizes induced mutation varies greatly among species, strains and genetic systems. Induced variability tends to enhance the respose to selection, but this effect may be delayed or prevented by an initial reduction in the heritability of induced variation. Significantly, the detrimental effects of harmful mutations in irradiated populations may exceed the beneficial effects of selection for adaptive characteristics. Selection for radioresistance may occur at lethal or sub-lethal radiation doses but dose relationships are highly variable. (author)

Selection of Avocado Plants Based on Fruit Characters, Fat Content, and Continual Harvest along The Year in West Java-Indonesia

OpenAIRE

Reni Lestari; Lazarus Agus Sukamto; Popi Aprilianti; Sri Wahyuni; Winda Utami Putri

2016-01-01

Avocado (Persea americana Mill.) belongs to Lauraceae family, is originated from lowland and highland tropical America region. Avocado plant was introduced to Indonesia in 1750 by Spanish. Fruit of avocado contains high unsaturated ( healthy) fat, protein, fiber, vitamins, minerals, and energy. Fruit of avocado can be eaten freshly, used as an additional ingredient cooking and material for cosmetics. Avocado fruits are available along the year in market cities of Indonesia but their fruits fl...

Evaluation of the results of the IAEA/FAO CRP on tropical transfer factors

International Nuclear Information System (INIS)

Twining, J.

1998-01-01

Future development of tropical countries will include nuclear power. This is particularly true following the recent attention given to the urgent need to reduce greenhouse gas emissions. From this, it is apparent that there is a need to have the ability to undertake dose assessments within tropical and sub-tropical regions. This includes knowledge of appropriate biological transfer factors for the region. However, most previous transfer factor studies were undertaken within temperate regions, predominantly in the Northern Hemisphere. Following a preliminary data survey, there was thus found to be a paucity of data for tropical and sub-tropical regions (excluding marine ecosystems). In an attempt to rectify this situation, the IAEA and FAO instigated a cooperative research program (CRP) entitled 'Transfer of radionuclides from air, soil and freshwater to the food chain of man in tropical and subtropical environments.' This paper is a synopsis of the findings of the three year CRP project. It is important to recognize that the data used in this presentation are derived from contributors and their colleagues in several countries. A list of chief investigators is given. Dr Martin Frissel, Secretary, European IUR, deserves a special mention for his collation of the CRP data. Some of his figures were used in the presentation or reproduced in this synopsis. The participants undertook regional literature and data surveys, field sampling and experimental investigations. The experimental studies were run by following, as closely as practicable, a suite of standard protocols that helped to reduce variability and errors. The experimental studies comprised two main groups: soil to plant, and: freshwater to fish. Quality assurance on analytical work was performed using intercomparison tests with standard reference materials. The reporting of data was also standardised to facilitate collation and subsequent multivariate statistical analysis. The statistical analysis of the entire

Selection of a plant location - A case study: Urea production using ...

African Journals Online (AJOL)

Selection of a plant location - A case study: Urea production using Calub Gas. ... The criteria are. amongst others, supply of raw materials and fuel, market proximity, water supply. waste ... To set up · critical factors for Ethiopian scenario

Clutch size declines with elevation in tropical birds

Science.gov (United States)

Boyce, A.J.; Freeman, Benjamin G.; Mitchell, Adam E.; Martin, Thomas E.

2015-01-01

Clutch size commonly decreases with increasing elevation among temperate-zone and subtropical songbird species. Tropical songbirds typically lay small clutches, thus the ability to evolve even smaller clutch sizes at higher elevations is unclear and untested. We conducted a comparative phylogenetic analysis using data gathered from the literature to test whether clutch size varied with elevation among forest passerines from three tropical biogeographic regions—the Venezuelan Andes and adjacent lowlands, Malaysian Borneo, and New Guinea. We found a significant negative effect of elevation on variation in clutch size among species. We found the same pattern using field data sampled across elevational gradients in Venezuela and Malaysian Borneo. Field data were not available for New Guinea. Both sets of results demonstrate that tropical montane species across disparate biogeographic realms lay smaller clutches than closely related low-elevation species. The environmental sources of selection underlying this pattern remain uncertain and merit further investigation.

Ecological restoration success is higher for natural regeneration than for active restoration in tropical forests

OpenAIRE

Crouzeilles, Renato; Ferreira, Mariana S.; Chazdon, Robin L.; Lindenmayer, David B.; Sansevero, Jerônimo B. B.; Monteiro, Lara; Iribarrem, Alvaro; Latawiec, Agnieszka E.; Strassburg, Bernardo B. N.

2017-01-01

Is active restoration the best approach to achieve ecological restoration success (the return to a reference condition, that is, old-growth forest) when compared to natural regeneration in tropical forests? Our meta-analysis of 133 studies demonstrated that natural regeneration surpasses active restoration in achieving tropical forest restoration success for all three biodiversity groups (plants, birds, and invertebrates) and five measures of vegetation structure (cover, density, litter, biom...

Trait shifts associated with the subshrub life-history strategy in a tropical savanna.

Science.gov (United States)

Giroldo, A B; Scariot, A; Hoffmann, W A

2017-10-01

Over the past 10 million years, tropical savanna environments have selected for small growth forms within woody plant lineages. The result has been the evolution of subshrubs (geoxyles), presumably as an adaptation to frequent fire. To evaluate the traits associated with the shift from tree to subshrub growth forms, we compared seed biomass, germination, survival, resprouting, biomass allocation, and photosynthesis between congeneric trees and subshrubs, and quantified phylogenetic conservatism. Despite large differences in adult morphology between trees and subshrub species, the differences are modest in seedlings, and most of the variation in traits was explained by genus, indicating considerable phylogenic conservatism. Regardless, tree seedlings invested more heavily in aboveground growth, compared to subshrubs, which is consistent with the adult strategy of savanna trees, which depend on a large resistant-fire stem. Subshrub seedlings also invest in greater non-structural carbohydrate reserves, likely as an adaptation to the high fire frequencies typical of tropical savannas. The modest differences as seedlings suggest that selective pressures during early development may not have contributed substantially to the evolution of the subshrub growth form and that the distinct allocation and life history must arise later in life. This is consistent with the interpretation that the subshrub growth form arose as a life-history strategy in which maturity is reached at a small stem size, allowing them to reproduce despite repeated fire-induced topkill. The convergent evolution of subshrubs within multiple tree lineages reaffirms the importance of fire in the origin and diversification of the flora of mesic savannas.

Genotyping-by-sequencing (GBS), an ultimate marker-assisted selection (MAS) tool to accelerate plant breeding

OpenAIRE

He, Jiangfeng; Zhao, Xiaoqing; Laroche, André; Lu, Zhen-Xiang; Liu, HongKui; Li, Ziqin

2014-01-01

Marker-assisted selection (MAS) refers to the use of molecular markers to assist phenotypic selections in crop improvement. Several types of molecular markers, such as single nucleotide polymorphism (SNP), have been identified and effectively used in plant breeding. The application of next-generation sequencing (NGS) technologies has led to remarkable advances in whole genome sequencing, which provides ultra-throughput sequences to revolutionize plant genotyping and breeding. To further broad...

Accumulation and long-term decline of radiocaesium contamination in tropical fruit trees

Science.gov (United States)

Anjos, R. M.; Mosquera, B.; Carvalho, C.; Sanches, N.; Bastos, J.; Gomes, P. R. S.; Macario, K.

2007-09-01

The accumulation of 137Cs, 40K and NH 4+ in several organs of tropical plants species were studied through measurements of its concentrations from mango, avocado, guava, papaya, banana and chili pepper trees. Our goal was to infer their differences in the uptake and translocation of such ions to the aboveground plant parts and to establish the suitability of using radiocaesium as a tracer for the plant uptake of nutrients. The results indicate Cs + is better tracer for K + as it is for NH 4+.

Accumulation and long-term decline of radiocaesium contamination in tropical fruit trees

International Nuclear Information System (INIS)

Anjos, R.M.; Mosquera, B.; Carvalho, C.; Sanches, N.; Bastos, J.; Gomes, P.R.S.; Macario, K.

2007-01-01

The accumulation of 137 Cs, 40 K and NH 4 + in several organs of tropical plants species were studied through measurements of its concentrations from mango, avocado, guava, papaya, banana and chili pepper trees. Our goal was to infer their differences in the uptake and translocation of such ions to the aboveground plant parts and to establish the suitability of using radiocaesium as a tracer for the plant uptake of nutrients. The results indicate Cs + is better tracer for K + as it is for NH 4 +

Ohcratoxin producing Aspergillus spp. Isolated from tropical soils in Sarawak, Malaysia

Directory of Open Access Journals (Sweden)

J.S.S. Seelan

2010-03-01

Full Text Available Aspergillus strains isolated from tropical soils were selected for additional characterization and for ochratoxin analysis, which was determined by ELISA method and high performance liquid chromatography (HPLC profiles. Because of its great morphological variability and mycotoxin production availability, 18 isolates of Aspergillus species were selected for this study. Only two isolates of these tropical soils, A. sulphureus and A. carbonarius, showed positive results for ohcratoxin (OA in lower concentration (0.05-0.10 µg/ml. Ochratoxin production by these species was confirmed by high performance liquid chromatography. HPLC analysis for ochratoxin producing A. sulphureus and A. carbonarius showed retention time, Rt value = 4.417 and Rt value = 4.081 respectively.

Draft genome sequence of bitter gourd (Momordica charantia), a vegetable and medicinal plant in tropical and subtropical regions.

Science.gov (United States)

Urasaki, Naoya; Takagi, Hiroki; Natsume, Satoshi; Uemura, Aiko; Taniai, Naoki; Miyagi, Norimichi; Fukushima, Mai; Suzuki, Shouta; Tarora, Kazuhiko; Tamaki, Moritoshi; Sakamoto, Moriaki; Terauchi, Ryohei; Matsumura, Hideo

2017-02-01

Bitter gourd (Momordica charantia) is an important vegetable and medicinal plant in tropical and subtropical regions globally. In this study, the draft genome sequence of a monoecious bitter gourd inbred line, OHB3-1, was analyzed. Through Illumina sequencing and de novo assembly, scaffolds of 285.5 Mb in length were generated, corresponding to ∼84% of the estimated genome size of bitter gourd (339 Mb). In this draft genome sequence, 45,859 protein-coding gene loci were identified, and transposable elements accounted for 15.3% of the whole genome. According to synteny mapping and phylogenetic analysis of conserved genes, bitter gourd was more related to watermelon (Citrullus lanatus) than to cucumber (Cucumis sativus) or melon (C. melo). Using RAD-seq analysis, 1507 marker loci were genotyped in an F2 progeny of two bitter gourd lines, resulting in an improved linkage map, comprising 11 linkage groups. By anchoring RAD tag markers, 255 scaffolds were assigned to the linkage map. Comparative analysis of genome sequences and predicted genes determined that putative trypsin-inhibitor and ribosome-inactivating genes were distinctive in the bitter gourd genome. These genes could characterize the bitter gourd as a medicinal plant. © The Author 2016. Published by Oxford University Press on behalf of Kazusa DNA Research Institute.

Tropical plant pathology: at home and abroad.

Science.gov (United States)

Thurston, H D

2001-01-01

I first describe my introduction to plant pathology and early experiences with employment, the environment, diseases, pests, and various plant pathologists. Then I recount a decade of stimulating studies at the University of Minnesota and the route I followed to a career in international agriculture with the Rockefeller Foundation in Colombia and later at Cornell University. My appreciation for and knowledge of traditional farmers and sustainable agriculture occurred as a slow awakening. Comments are made regarding problems, principles, and satisfactions associated with the improvement of efforts to aid food production in developing countries. My curious love affair with root and tuber crops, especially cassava, is explained and readily defended. My favorite pathogens, Phytophthora infestans and Ralstonia solanacearum, among others, are considered. The pleasures and satisfactions of teaching, writing, and sabbatical leaves are related. Finally, thoughts on the balance between basic and applied research in plant pathology are offered with significant nervousness about the future of our discipline.

The Role of Earthworms in Tropics with Emphasis on Indian Ecosystems

Directory of Open Access Journals (Sweden)

Radha D. Kale

2010-01-01

Full Text Available The paper highlights the research carried out by different scientists in India on aspects of earthworm population dynamics and species diversity, associated with other soil fauna and microflora. It also deals with the importance of earthworm activity on physicochemical properties of soil with reference to India and other tropical countries. Stress is laid on the earthworm plant association and importance of the secretions of earthworms as plant growth stimulators. Moreover, the earthworm species reported and being utilized for vermicomposting in India are discussed, since vermicomposting is the ultimate technology which renders for the improvement of soil fertility status and plant growth. Earthworms serve as indicators of soil status such as the level of contamination of pollutants: agrochemicals, heavy metals, toxic substances, and industrial effluents; human-induced activities: land-management practices and forest degradation. In all these fields there is lacuna with respect to contributions from India when compared to the available information from other tropical countries. There is lot of scope in the field of research on earthworms to unravel the importance of these major soil macrofauna from holistic ecological studies to the molecular level.

The Role of Earthworms in Tropics with Emphasis on Indian Ecosystems

International Nuclear Information System (INIS)

Kale, R.D.; Karmegam, N.

2010-01-01

The paper highlights the research carried out by different scientists in India on aspects of earthworm population dynamics and species diversity, associated with other soil fauna and microflora. It also deals with the importance of earthworm activity on physicochemical properties of soil with reference to India and other tropical countries. Stress is laid on the earthworm plant association and importance of the secretions of earthworms as plant growth stimulators. Moreover, the earthworm species reported and being utilized for vermicomposting in India are discussed, since vermicomposting is the ultimate technology which renders for the improvement of soil fertility status and plant growth. Earthworms serve as indicators of soil status such as the level of contamination of pollutants: agrochemicals, heavy metals, toxic substances, and industrial effluents; human-induced activities: land-management practices and forest degradation. In all these fields there is lacuna with respect to contributions from India when compared to the available information from other tropical countries. There is lot of scope in the field of research on earthworms to unravel the importance of these major soil macro fauna from holistic ecological studies to the molecular level.

The content changes of selected phenolic compounds during processing of medicinal plants

OpenAIRE

GROŠAFTOVÁ, Blanka

2007-01-01

This work was aimed to the problem of change of the content of selected phenolic substances during treatment and storage of medical plants. Flavonoids represent small, but very important group of phenolic compounds. The biggest attention was paid to quercetin and rutine.Content of phenolic substances was determined by method of micellar electrokinetic capillary chromatography (MECC) in case of 6 medicinal plants usually used in traditional and modern medicine.

Gall inducing arthropods from a seasonally dry tropical forest in Serra do Cipó, Brazil Artrópodes indutores de galhas em Floresta Sazonal Tropical Seca da Serra do Cipó, Brasil

Directory of Open Access Journals (Sweden)

Marcel Serra Coelho

2009-01-01

Full Text Available Highly diverse forms of galling arthropods can be identified in much of southeastern Brazil's vegetation. Three fragments of a Seasonally Dry Tropical Forest (SDTF located in the southern range of the Espinhaço Mountains were selected for study in the first survey of galling organisms in such tropical vegetation. Investigators found 92 distinct gall morphotypes on several organs of 51 host plant species of 19 families. Cecidomyiidae (Diptera was the most prolific gall-inducing species, responsible for the largest proportion of galls (77% observed. Leaves were the most frequently galled plant organ (63%, while the most common gall morphotype was of a spherical shape (30%. The two plant species, Baccharis dracunculifolia (Asteraceae and Celtis brasiliensis (Cannabaceae, presented the highest number of gall morphtypes, displaying an average of 5 gall morphotypes each. This is the first study of gall-inducing arthropods and their host plant species ever undertaken in a Brazilian SDTF ecosystem. Given the intense human pressure on SDTFs, the high richness of galling arthropods, and implied floral host diversity found in this study indicates the need for an increased effort to catalogue the corresponding flora and fauna, observe their intricate associations and further understand the implications of such rich diversity in these stressed and vulnerable ecosystems.Artrópodes indutores de galhas são muito ricos em espécies nas formações vegetais no sudeste do Brasil. Três fragmentos de Floresta Sazonal Tropical Seca (FSTS foram selecionados nas montanhas do sudeste da cadeia do Espinhaço para a primeira pesquisa de organismos indutores de galhas nesse tipo de vegetação. Encontramos 92 morfotipos distintos de galhas em vários órgãos de 51 espécies de plantas hospedeiras pertencentes à 19 famílias. A maioria das galhas (77% foi induzida pela família Cecidomyiidae (Diptera. A folha foi o órgão mais atacado (63%, enquanto o morfotipo mais

Selective inhibition of plant serine hydrolases by agrochemicals revealed by competitive ABPP.

Science.gov (United States)

Kaschani, Farnusch; Nickel, Sabrina; Pandey, Bikram; Cravatt, Benjamin F; Kaiser, Markus; van der Hoorn, Renier A L

2012-01-15

Organophosphate and -phosphonates and their thio derivatives are often used in agroindustry as herbicides and insecticides, but their potential off-targets in the plant are poorly investigated. Here, we use competitive activity-based protein profiling (ABPP) of serine hydrolases (SHs) to detect targets of these agrochemicals and other compounds in Arabidopsis thaliana. Using broad-range and specific probes, and by overexpression of various SHs in planta, we are able to confirm eight SH-compound interactions, including selective inhibition of carboxylesterase CXE12, prolyloligopeptidase, methylesterase MES2 and tripeptidyl peptidase TPP2. These observations can be used for the design of novel probes and selective inhibitors and may help to assess physiological effects of agrochemicals on crop plants. Copyright © 2011 Elsevier Ltd. All rights reserved.

A Site Selection Model for a Straw-Based Power Generation Plant with CO2 Emissions

Directory of Open Access Journals (Sweden)

Hao Lv

2014-10-01

Full Text Available The decision on the location of a straw-based power generation plant has a great influence on the plant’s operation and performance. This study explores traditional theories for site selection. Using integer programming, the study optimizes the economic and carbon emission outcomes of straw-based power generation as two objectives, with the supply and demand of straw as constraints. It provides a multi-objective mixed-integer programming model to solve the site selection problem for a straw-based power generation plant. It then provides a case study to demonstrate the application of the model in the decision on the site selection for a straw-based power generation plant with a Chinese region. Finally, the paper discusses the result of the model in the context of the wider aspect of straw-based power generation.

Screening and antibacterial efficacy of selected Indian medicinal plants

Institute of Scientific and Technical Information of China (English)

Suresh Mickymaray; Mohammad Saleh Al Aboody; Pradipta Kumar Rath; Panneerselvam Annamalai; Thajuddin Nooruddin

2016-01-01

Objective: To evaluate the antibacterial efficacy of five Indian medicinal plants such as Acalypha indica L.(A. indica), Aerva lanata(L.) Juss. ex Schult.(A. lanata), Clerodendrum inerme(L.) Gaertn., Pergularia daemia(Forsk.) Chiov. and Solanum surattense Burm. f. against opportunistic bacterial pathogens isolated from HIV infected patients for the potential phytoconstituents in plant extracts.Methods: The opportunistic bacterial pathogens such as Escherichia coli(E. coli),Pseudomonas aeruginosa, Salmonella typhi and Serratia marcescens from Gramnegative group and Staphylococcus aureus from Gram-positive group were isolated from HIV infected patients. The antibacterial efficacy of ethanolic extracts of selected medicinal plants was carried out by disc diffusion method. The potential phytoconstituents of medicinal plant extracts were identified by gas chromatography and mass spectrometry(GC–MS) analysis.Results: Among the five medicinal plants tested, A. indica and A. lanata showed the significant antibacterial activity. A. indica showed potential activity against Staphylococcus aureus and E. coli. A. lanata significantly exhibited antibacterial activity against E. coli, Salmonella typhi and Pseudomonas aeruginosa. A total of 19 phytoconstituents were identified in the ethanolic extract of A. indica and A. lanata by GC–MS analysis respectively.Conclusions: The results of the present investigation revealed that A. indica and A. lanata, possessed significant antibacterial activity when compared with the other plant extracts tested. The presence of 3-O-methyl-D-glucose by GC–MS analysis in both A. indica and A. lanata extracts has not been reported elsewhere in the literature and the findings in this study could be the first one to report.

The design and application of a radiological consequence model for tropical and subtropical regions

International Nuclear Information System (INIS)

Domel, R.U.; Harris, F.F.; Crawford, J.

1997-01-01

The post Chernobyl era has seen the development of a plethora of radiological consequence models. At ANSTO, a model is being developed with a user-friendly interface which will assess the radiological consequences, after an incident, in tropical and sub-tropical climates. The model combines specific regional dispersion and deposition data to determine the dose to man via the major pathways of external and internal irradiation. The external irradiation data will need to include lifestyle information such as time spent L indoors/outdoors, the high/low activity times of the different groups of people (especially critical groups) and shielding factors for housing. The internal irradiation data requires food consumption values, effect of food processing and transfer parameters (soil to plant, plant to animal) to be obtained for tropical and sub-tropical regions. The model allows the user to specify the radionuclide of interest, the age of the person receiving l the dose, race, dietary components and lifestyle. The operator may use a number of default categories, but regional information may also be entered and incorporated into the radiological model allowing assessment of dose to critical groups using site specific data. Initially, the model will deal with the South East Asian region but flexibility has been incorporated into the design to allow application in other regions. A geographic information system is used for display of all input and output data allowing quick access to not only the results but also the underlying assumptions. The model also has portability across computer platforms. The model has been developed to provide a tool for directing future research, has application as a planing tool for emergency response operations but its priority lies in understanding the behaviour of radionuclides in the tropical and sub-tropical environments and their effect on humankind

An invasive plant alters phenotypic selection on the vegetative growth of a native congener.

Science.gov (United States)

Beans, Carolyn M; Roach, Deborah A

2015-02-01

The ecological consequences of plant competition have frequently been tested, but the evolutionary outcomes of these interactions have gone largely unexplored. The study of species invasions can make an important contribution to this field of research by allowing us to watch ecological and evolutionary processes unfold as a novel species is integrated into a plant community. We explored the ecological and evolutionary impact of an invasive jewelweed, Impatiens glandulifera, on a closely related native congener, I. capensis and asked: (1) Does the presence of the invasive jewelweed alter the fitness of native jewelweed populations? (2) Does the invasive jewelweed affect the vegetative growth of the native congener? and (3) Does the invasive jewelweed alter phenotypic selection on the vegetative traits of the native congener? We used a greenhouse competition experiment, an invasive species removal field experiment, and a survey of natural populations. We show that when the invasive jewelweed is present, phenotypic selection favors native jewelweed individuals investing less in rapid upward growth and more in branching and fruiting potential through the production of nodes. This research demonstrates that invasive plants have the potential to greatly alter natural selection on native competitors. Studies investigating altered selection in invaded communities can reveal the potential evolutionary impact of invasive competitors, while deepening our understanding of the more general role of competition in driving plant evolution and permitting species coexistence. © 2015 Botanical Society of America, Inc.

Tropical Soil Chemistry

DEFF Research Database (Denmark)

Borggaard, Ole K.

and environmental protection. Tropical Soil Chemistry by Ole K. Borggaard provides an overview of the composition, occurrence, properties, processes, formation, and environmental vulnerability of various tropical soil types (using American Soil Taxonomy for classification). The processes and the external factors...... soil chemical issues are also presented to assess when, why, and how tropical soils differ from soils in other regions. This knowledge can help agricultural specialists in the tropics establish sustainable crop production. Readers are assumed to be familiar with basic chemistry, physics...

Study of in vitro antimicrobial and antiproliferative activities of selected Saharan plants.

Science.gov (United States)

Palici, Ionut F; Liktor-Busa, Erika; Zupkó, István; Touzard, Blaise; Chaieb, Mohamed; Urbán, Edit; Hohmann, Judit

2015-12-01

The aim of the present study was the evaluation of the antimicrobial and antiproliferative activities of selected Saharan species, which are applied in the traditional medicine but not studied thoroughly from chemical and pharmacological point of view. The studied plants, namely Anthyllis henoniana, Centropodia forskalii, Cornulaca monacantha, Ephedra alata var. alenda, Euphorbia guyoniana, Helianthemum confertum, Henophyton deserti, Moltkiopsis ciliata and Spartidium saharae were collected from remote areas of North Africa, especially from the Tunisian region of Sahara. After drying and applying the appropriate extraction methods, the plant extracts were tested in antimicrobial screening assay, performed on 19 Gram-positive and -negative strains of microbes. The inhibition zones produced by plant extracts were determined by disc-diffusion method. Remarkable antibacterial activities were exhibited by extracts of Ephedra alata var. alenda and Helianthemum confertum against B. subtilis, M. catarrhalis and methicillin-resistant and non-resistant S. aureus. Minimum inhibitory concentrations of these two species were also determined. Antiproliferative effects of the extracts were evaluated against 4 human adherent cell lines (HeLa, A431, A2780 and MCF7). Notable cell growth inhibition was found for extract of Helianthemum confertum and Euphorbia guyoniana. Our results provided data for selection of some plant species for further detailed pharmacological and phytochemical examinations.

Enrichment of tropical peat with micronutrients for agricultural applications: evaluation of adsorption and desorption processes

Energy Technology Data Exchange (ETDEWEB)

Melo, Camila de A.; Oliveira, Lilian K. de; Fraceto, Leonardo F.; Rosa, Andre H., E-mail: ahrosa@sorocaba.unesp.br [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Sorocaba, SP (Brazil). Dept. de Engenharia Ambiental; Goveia, Danielle [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Araraquara, SP (Brazil). Inst. de Quimica

2014-01-15

The objective of this work was to evaluate the adsorption and desorption of micronutrients in tropical peats, from the perspective of potential agricultural applications. Adsorption experiments were performed at different pH values, using solutions containing individual and multiple metal ions. Maximum adsorption capacity occurred at pH 6.0, and the order of affinity was Cu > Fe > Co > Ni > Zn = Mn. Release of the micronutrients was evaluated at different pH values, using an aqueous medium as well as soil and plants. Release of the micronutrients was most efficient at pH 6.0, and followed the order: Fe > Zn > Mn > Co = Ni > Cu. Micronutrient release to the soil was accompanied by uptake by the plant. The use of tropical peat enriched with micronutrients could contribute to improved agricultural productivity, since the release profile of the micronutrients can effectively stimulate plant growth. (author)

Hydrocarbon degradation and plant colonization of selected bacterial strains isolated from the rhizsophere and plant interior of Italian ryegrass and Birdsfoot trefoil

Science.gov (United States)

Sohail, Y.; Andria, V.; Reichenauer, T. G.; Sessitsch, A.

2009-04-01

Hydrocarbon-degrading strains were isolated from the rhizosphere, root and shoot interior of Italian ryegrass (Lolium multiflorum var. Taurus), Birdsfoot trefoil (Lotus corniculatus var. Leo) grown in a soil contaminated with petroleum oil. Strains were tested regarding their phylogeny and their degradation efficiency. The most efficient strains were tested regarding their suitability to be applied for phytoremediation of diesel oils. Sterilized and non-sterilized agricultural soil, with and with out compost, were spiked with diesel and used for planting Italian ryegrass and birdsfoot trefoil. Four selected strains with high degradation activities, derived from the rhizosphere and plant interior, were selected for individual inoculation. Plants were harvested at flowering stage and plant biomass and hydrocarbon degradation was determined. Furthermore, it was investigated to which extent the inoculant strains were able to survive and colonize plants. Microbial community structures were analysed by 16S rRNA and alkB gene analysis. Results showed efficient colonization by the inoculant strains and improved degradation by the application of compost combined with inoculation as well as on microbial community structures will be presented.

AQUATIC PLANT SPECIATION AFFECTED BY DIVERSIFYING SELECTION OF ORGANELLE DNA REGIONS(1).

Science.gov (United States)

Kato, Syou; Misawa, Kazuharu; Takahashi, Fumio; Sakayama, Hidetoshi; Sano, Satomi; Kosuge, Keiko; Kasai, Fumie; Watanabe, Makoto M; Tanaka, Jiro; Nozaki, Hisayoshi

2011-10-01

Many of the genes that control photosynthesis are carried in the chloroplast. These genes differ among species. However, evidence has yet to be reported revealing the involvement of organelle genes in the initial stages of plant speciation. To elucidate the molecular basis of aquatic plant speciation, we focused on the unique plant species Chara braunii C. C. Gmel. that inhabits both shallow and deep freshwater habitats and exhibits habitat-based dimorphism of chloroplast DNA (cpDNA). Here, we examined the "shallow" and "deep" subpopulations of C. braunii using two nuclear DNA (nDNA) markers and cpDNA. Genetic differentiation between the two subpopulations was measured in both nDNA and cpDNA regions, although phylogenetic analyses suggested nuclear gene flow between subpopulations. Neutrality tests based on Tajima's D demonstrated diversifying selection acting on organelle DNA regions. Furthermore, both "shallow" and "deep" haplotypes of cpDNA detected in cultures originating from bottom soils of three deep environments suggested that migration of oospores (dormant zygotes) between the two habitats occurs irrespective of the complete habitat-based dimorphism of cpDNA from field-collected vegetative thalli. Therefore, the two subpopulations are highly selected by their different aquatic habitats and show prezygotic isolation, which represents an initial process of speciation affected by ecologically based divergent selection of organelle genes. © 2011 Phycological Society of America.

Accumulation and long-term decline of radiocaesium contamination in tropical fruit trees

Energy Technology Data Exchange (ETDEWEB)

Anjos, R.M. [Instituto de Fisica da Universidade Federal Fluminense, Av. Litoranea s/n, Gragoata, 24210-346 Niteroi, RJ (Brazil)], E-mail: meigikos@if.uff.br; Mosquera, B.; Carvalho, C.; Sanches, N.; Bastos, J.; Gomes, P.R.S.; Macario, K. [Instituto de Fisica da Universidade Federal Fluminense, Av. Litoranea s/n, Gragoata, 24210-346 Niteroi, RJ (Brazil)

2007-09-21

The accumulation of {sup 137}Cs, {sup 40}K and NH{sub 4}{sup +} in several organs of tropical plants species were studied through measurements of its concentrations from mango, avocado, guava, papaya, banana and chili pepper trees. Our goal was to infer their differences in the uptake and translocation of such ions to the aboveground plant parts and to establish the suitability of using radiocaesium as a tracer for the plant uptake of nutrients. The results indicate Cs{sup +} is better tracer for K{sup +} as it is for NH{sub 4}{sup +}.

Tropical Freshwater Biology

African Journals Online (AJOL)

Tropical Freshwater Biology promotes the publication of scientific contributions in the field of freshwater biology in the tropical and subtropical regions of the world. One issue is published annually but this number may be increased. Original research papers and short communications on any aspect of tropical freshwater ...

Criteria for selecting measures of plant information with application to nuclear reactors

International Nuclear Information System (INIS)

Kiguchi, T.; Sheridan, T.B.

1979-01-01

Criteria for selecting from alternative measures of plant information have been derived by information theory and the expected-value model of decision theory. Two criteria derived by information theory are minimum ''uncertainty'' of judgement of plant states, and maximum ''surprise'' of human operators. Two criteria derived by decision theory are maximum expected reward to operators, and maximum ratio of the maximum and next-to-maximum expected rewards. These four criteria have been evaluated experimentally in application to human monitoring problems of three ''plants'': an abstract laboratory exercise, a small research reactor, and a conventional nuclear power plant (high-fidelity training simulator). The results show that the criteria derived by decision theory are superior to the others from the viewpoint of correct rate of human subjects' judgement

An integrated approach to site selection for nuclear power plants

International Nuclear Information System (INIS)

Hassan, E.M.A.

1975-01-01

A method of analysing and evaluating the large number of factors influencing site selection is proposed, which can interrelate these factors and associated problems in an integrated way and at the same time establish a technique for site evaluation. The objective is to develop an integrated programme that illustrates the complexity and dynamic interrelationships of the various factors to develop an improved understanding of the functions and objectives of siting nuclear power plants and would aim finally at the development of an effective procedure and technique for site evaluation and/or comparative evaluation for making rational site-selection decisions. (author)

Spatio-temporal dynamics of the tropical rain forest

Energy Technology Data Exchange (ETDEWEB)

Chave, J. [CEN Saclay, Gif-sur-Yvette (France). Service de Physique de l' Etat Condense

2000-07-01

Mechanisms which drive the dynamics of forest ecosystems are complex, from seedling establishment to pollination, and seed dispersal by animals, running water or wind. These processes are more complex when the ecosystem shelters a large number of species and of vegetative forms, as it is the case in the tropical rainforest. To take them into account, we must develop and use models. I present a review of the fundamental mechanisms for the of a natural forest dynamics - photosynthesis, tree growth, recruitment and mortality - as well as a description of the past and of the present of tropical rainforests. This information is used to develop a spatially-explicit and individual-based forest model. Simplified models are deduced from it, and they serve to address more specific issues, such as the resilience of the forest to climate disturbances, or savanna-forest dynamics. The last topic is related to the spatio-temporal description of tropical plant biodiversity. A detailed introduction to the problem is provided, and models accounting for the maintenance of diversity are compared. These models include non spatial as well a spatial approaches (branching anihilating random walks and voter model with mutation). (orig.)

Fluid selection for the Organic Rankine Cycle (ORC) in biomass power and heat plants

International Nuclear Information System (INIS)

Drescher, Ulli; Brueggemann, Dieter

2007-01-01

In small solid biomass power and heat plants, the ORC is used for cogeneration. This application shows constraints different from other ORC. These constraints are described and an adapted power plant design is presented. The new design influences the selection criteria of working fluids. A software has been developed to find thermodynamic suitable fluids for ORC in biomass power and heat plants. Highest efficiencies are found within the family of alkylbenzenes

Comparative Mapping of Seed Dormancy Loci Between Tropical and Temperate Ecotypes of Weedy Rice (Oryza sativa L.

Directory of Open Access Journals (Sweden)

Lihua Zhang

2017-08-01

Full Text Available Genotypic variation at multiple loci for seed dormancy (SD contributes to plant adaptation to diverse ecosystems. Weedy rice (Oryza sativa was used as a model to address the similarity of SD genes between distinct ecotypes. A total of 12 quantitative trait loci (QTL for SD were identified in one primary and two advanced backcross (BC populations derived from a temperate ecotype of weedy rice (34.3°N Lat.. Nine (75% of the 12 loci were mapped to the same positions as those identified from a tropical ecotype of weedy rice (7.1°N Lat.. The high similarity suggested that the majority of SD genes were conserved during the ecotype differentiation. These common loci are largely those collocated/linked with the awn, hull color, pericarp color, or plant height loci. Phenotypic correlations observed in the populations support the notion that indirect selections for the wild-type morphological characteristics, together with direct selections for germination time, were major factors influencing allelic distributions of SD genes across ecotypes. Indirect selections for crop-mimic traits (e.g., plant height and flowering time could also alter allelic frequencies for some SD genes in agroecosystems. In addition, 3 of the 12 loci were collocated with segregation distortion loci, indicating that some gametophyte development genes could also influence the genetic equilibria of SD loci in hybrid populations. The SD genes with a major effect on germination across ecotypes could be used as silencing targets to develop transgene mitigation (TM strategies to reduce the risk of gene flow from genetically modified crops into weed/wild relatives.

Evolution of resistance to a multiple-herbivore community: genetic correlations, diffuse coevolution, and constraints on the plant's response to selection.

Science.gov (United States)

Wise, Michael J; Rausher, Mark D

2013-06-01

Although plants are generally attacked by a community of several species of herbivores, relatively little is known about the strength of natural selection for resistance in multiple-herbivore communities-particularly how the strength of selection differs among herbivores that feed on different plant organs or how strongly genetic correlations in resistance affect the evolutionary responses of the plant. Here, we report on a field study measuring natural selection for resistance in a diverse community of herbivores of Solanum carolinense. Using linear phenotypic-selection analyses, we found that directional selection acted to increase resistance to seven species. Selection was strongest to increase resistance to fruit feeders, followed by flower feeders, then leaf feeders. Selection favored a decrease in resistance to a stem borer. Bootstrapping analyses showed that the plant population contained significant genetic variation for each of 14 measured resistance traits and significant covariances in one-third of the pairwise combinations of resistance traits. These genetic covariances reduced the plant's overall predicted evolutionary response for resistance against the herbivore community by about 60%. Diffuse (co)evolution was widespread in this community, and the diffuse interactions had an overwhelmingly constraining (rather than facilitative) effect on the plant's evolution of resistance. © 2013 The Author(s). Evolution © 2013 The Society for the Study of Evolution.

Egg laying site selection by a host plant specialist leaf miner moth at two intra-plant levels in the northern Chilean Atacama Desert

Directory of Open Access Journals (Sweden)

José Storey-Palma

2014-09-01

Full Text Available Egg laying site selection by a host plant specialist leaf miner moth at two intra-plant levels in the northern Chilean Atacama Desert. The spatial distribution of the immature stages of the leaf miner Angelabella tecomae Vargas & Parra, 2005 was determined at two intra-plant levels (shoot and leaflet on the shrub Tecoma fulva fulva (Cav. D. Don (Bignoniaceae in the Azapa valley, northern Chilean Atacama Desert. An aggregated spatial pattern was detected for all the immature stages along the shoot, with an age dependent relative position: eggs and first instar larvae were clumped at apex; second, third and fourth instar larvae were mostly found at intermediate positions; meanwhile the spinning larva and pupa were clumped at basis. This pattern suggests that the females select new, actively growing leaflets for egg laying. At the leaflet level, the immature stages were found more frequently at underside. Furthermore, survivorship was higher for larvae from underside mines. All these results highlight the importance of an accurate selection of egg laying site in the life history of this highly specialized leaf miner. By contrast, eventual wrong choices in the egg laying site selection may be associated with diminished larval survivorship. The importance of the continuous availability of new plant tissue in this highly human modified arid environment is discussed in relation with the observed patterns.

Leaf life span plasticity in tropical seedlings grown under contrasting light regimes

OpenAIRE

Vincent, Grégoire

2006-01-01

Background and Aims The phenotypic plasticity of leaf life span in response to low resource conditions has a potentially large impact on the plant carbon budget, notably in evergreen species not subject to seasonal leaf shedding, but has rarely been well documented. This study evaluates the plasticity of leaf longevity, in terms of its quantitative importance to the plant carbon balance under limiting light. Methods Seedlings of four tropical tree species with contrasting light requirements (...

Applications of NASA TROPICS Data for Tropical Cyclone Analysis, Nowcasting, and Impacts

Science.gov (United States)

Zavodsky, B.; Dunion, J. P.; Blackwell, W. J.; Braun, S. A.; Green, D. S.; Velden, C.; Adler, R. F.; Cossuth, J.; Murray, J. J.; Brennan, M. J.

2017-12-01

The National Aeronautics and Space Administration (NASA) Time-Resolved Observations of Precipitation structure and storm Intensity with a Constellation of Smallsats (TROPICS) mission is a constellation of state-of-the-science observing platforms that will measure temperature and humidity soundings and precipitation with spatial resolution comparable to current operational passive microwave sounders but with unprecedented temporal resolution. TROPICS is a cost-capped ($30M) Venture-class mission funded by the NASA Earth Science Division. The mission is comprised of a constellation of 3 unit (3U) SmallSats, each hosting a 12-channel passive microwave spectrometer based on the Micro-sized Microwave Atmospheric Satellite 2 (MicroMAS-2) developed at MIT LL. TROPICS will provide imagery near 91 and 205 GHz, temperature sounding near 118 GHz, and moisture sounding near 183 GHz. Spatial resolution at nadir will be around 27 km for temperature and 17 km for moisture and precipitation. The swath width is approximately 2000 km. TROPICS enables temporal resolution similar to geostationary orbit but at a much lower cost, demonstrating a technology that could impact the design of future Earth-observing missions. The TROPICS satellites for the mission are slated for delivery to NASA in 2019 with potential launch opportunities in 2020. The primary mission objective of TROPICS is to relate temperature, humidity, and precipitation structure to the evolution of tropical cyclone (TC) intensity. This abstract summarizes the outcomes of the 1st TROPICS Applications Workshop, held from May 8-10, 2017 at the University of Miami. At this meeting, a series of presentations and breakout discussions in the topical areas of Tropical Cyclone Dynamics, Tropical Cyclone Analysis and Nowcasting, Tropical Cyclone Modeling and Data Assimilation, and Terrestrial Impacts were convened to identify applications of the mission data and to begin to establish a community of end-users who will be able to

The Genesis of Tropical Cyclone Bilis (2000) Associated with Cross-equatorial Surges

Institute of Scientific and Technical Information of China (English)

XU Yamei

2011-01-01

The purpose of this paper is to explore how a tropical cyclone forms from a pre-existing large-scale depression which has been observed and associated with cross-equatorial surges in the western North Pacific. Tropical cyclone Bilis (2000) was selected as the case to study. The research data used are from the results of the non-hydrostatic mesoscale model (MM5), which has successfully simulated the transformation of a pre-existing weak large-scale tropical depression into a strong tropical storm. The scale separation technique is used to separate the synoptic-scale and sub-synoptic-scale fields from the model output fields. The scale-separated fields show that the pre-existing synoptic-scale tropical depression and the subsynoptic scale tropical cyclone formed later were different scale systems from beginning to end. It is also shown that the pre-existing synoptic-scale tropical depression did not contract to become the tropical cyclone. A series of weak, sub-synoptic-scale low and high pressure systems appeared and disappeared in the synopticscale depression, with one of the low systems near the center of the synoptic-scale depression having deepened to become the tropical cyclone. The roles of the synoptic-scale flow and the sub-synoptic scale disturbances in the formation of the tropical cyclone are investigated by diagnoses of the scale-separated vertical vorticity equation. The results show that the early development of the sub-synoptic scale vortex was fundamentally dependent on the strengthening synoptic-scale environmental depression. The depression was strengthened by cross-equatorial surges, which increased the convergence of the synoptic-scale depression at low levels and triggered the formation of the tropical cyclone.

Neglected tropical diseases

Directory of Open Access Journals (Sweden)

David Molyneux

2013-08-01

Full Text Available Seventeen neglected tropical diseases (NTDs have been identified by the World Health Organization (WHO. It is estimated that over 1 billion people are infected with NTDs, with a further 1 billion at risk. The majority of NTDs occur in the tropics and sub-tropics and have particular characteristics in common.

The contribution of large trees to total transpiration rates in a pre-montane tropical forest and its implications for selective logging practices

Science.gov (United States)

Orozco, G.; Moore, G. W.; Miller, G. R.

2012-12-01

In the humid tropics, conservationists generally prefer selective logging practices over clearcutting. Large valuable timber is removed while the remaining forest is left relatively undisturbed. However, little is known about the impact of selective logging on site water balance. Because large trees have very deep sapwood and exposed canopies, they tend to have high transpiration. The first objective was to evaluate the methods used for scaling sap flow measurements to the watershed with particular emphasis on large trees. The second objective of this study was to determine the relative contribution of large trees to site water balance. Our study was conducted in a pre-montane transitional forest at the Texas A&M University Soltis Center in north-central Costa Rica. During the period between January and July 2012, sap flux was monitored in a 30-m diameter plot within a 10-ha watershed. Two pairs of heat dissipation sensors were installed in the outer 0-20 mm of each of 15 trees selected to represent the full range of tree sizes. In six of the largest trees, depth profiles were recorded at 10-mm intervals to a depth of 60 mm using compensation heat pulse sensors. To estimate sapwood basal area of the entire watershed, a stand survey was conducted in three 30-m-diameter plots. In each plot, we measured basal area of all trees and estimated sapwood basal area from sapwood depth measured in nearly half of the trees. An estimated 36.5% of the total sapwood area in this watershed comes from the outer 20 mm of sapwood, with the remaining 63.5% of sapwood from depths deeper than 20 mm. Nearly 13% of sapwood is from depths beyond 60 mm. Sap velocity profiles indicate the highest flow rates occurred in the 0-2 cm depths, with declines of 17% and 25% in the 20-40 mm and 40-60 mm ranges, respectively. Our results demonstrate the need to measure sap velocity profiles in large tropical trees. If total transpiration had been estimated solely from the 0-20 mm heat dissipation

A Method to Select Human–System Interfaces for Nuclear Power Plants

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Jacques V. Hugo

2016-02-01

Full Text Available The new generation of nuclear power plants (NPPs will likely make use of state-of-the-art technologies in many areas of the plant. The analysis, design, and selection of advanced human–system interfaces (HSIs constitute an important part of power plant engineering. Designers need to consider the new capabilities afforded by these technologies in the context of current regulations and new operational concepts, which is why they need a more rigorous method by which to plan the introduction of advanced HSIs in NPP work areas. Much of current human factors research stops at the user interface and fails to provide a definitive process for integration of end user devices with instrumentation and control and operational concepts. The current lack of a clear definition of HSI technology, including the process for integration, makes characterization and implementation of new and advanced HSIs difficult. This paper describes how new design concepts in the nuclear industry can be analyzed and how HSI technologies associated with new industrial processes might be considered. It also describes a basis for an understanding of human as well as technology characteristics that could be incorporated into a prioritization scheme for technology selection and deployment plans.

Catch the Best: Novel Screening Strategy to Select Stress Protecting Agents for Crop Plants

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Christin Zachow

2013-11-01

Full Text Available Climate change increases stress levels for crops and affects the economic and environmental aspects of agricultural management systems. The application of stress tolerance-mediating microorganisms is an auspicious strategy for improving crop protection, and as such, we developed a direct selection strategy to obtain cultivable microorganisms from promising bioresources using the bait plants, maize, oilseed rape, sorghum and sugar beet. Alpine mosses, lichens and primrose were selected as bioresources, as each is adapted to adverse environmental conditions. A 10% crop-specific selection was found for bait plant rhizosphere communities using cultivation-independent fingerprints, and their potential role as stress protecting agents (SPA was evaluated following the cultivation of captured bacteria. In addition to assays identifying phytopathogen antagonism and plant growth promotion capacities, our evaluation included those that test the ability to allocate nutrients. Moreover, we developed new assays to measure tolerance in diverse stress conditions. A score scheme was applied to select SPAs with desired properties, and three Pseudomonas species with pronounced antagonistic activity that showed elevated tolerance to desiccation and an improved seed germination rate were subsequently chosen. Screening for environmentally-conditioned and host-adapted microorganisms provides a novel tool for target-oriented exploitation of microbial bioresources for the management of ecofriendly crops facing biotic and abiotic stresses.

In-silico Leishmania Target Selectivity of Antiparasitic Terpenoids

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Ifedayo Victor Ogungbe

2013-07-01

Full Text Available Neglected Tropical Diseases (NTDs, like leishmaniasis, are major causes of mortality in resource-limited countries. The mortality associated with these diseases is largely due to fragile healthcare systems, lack of access to medicines, and resistance by the parasites to the few available drugs. Many antiparasitic plant-derived isoprenoids have been reported, and many of them have good in vitro activity against various forms of Leishmania spp. In this work, potential Leishmania biochemical targets of antiparasitic isoprenoids were studied in silico. Antiparasitic monoterpenoids selectively docked to L. infantum nicotinamidase, L. major uridine diphosphate-glucose pyrophosphorylase and methionyl t-RNA synthetase. The two protein targets selectively targeted by germacranolide sesquiterpenoids were L. major methionyl t-RNA synthetase and dihydroorotate dehydrogenase. Diterpenoids generally favored docking to L. mexicana glycerol-3-phosphate dehydrogenase. Limonoids also showed some selectivity for L. mexicana glycerol-3-phosphate dehydrogenase and L. major dihydroorotate dehydrogenase while withanolides docked more selectively with L. major uridine diphosphate-glucose pyrophosphorylase. The selectivity of the different classes of antiparasitic compounds for the protein targets considered in this work can be explored in fragment- and/or structure-based drug design towards the development of leads for new antileishmanial drugs.

Tropical Rainforests.

Science.gov (United States)

Nigh, Ronald B.; Nations, James D.

1980-01-01

Presented is a summary of scientific knowledge about the rainforest environment, a tropical ecosystem in danger of extermination. Topics include the current state of tropical rainforests, the causes of rainforest destruction, and alternatives of rainforest destruction. (BT)

Transpiration efficiency of a tropical pioneer tree (Ficus insipida) in relation to soil fertility.

Science.gov (United States)

Cernusak, Lucas A; Winter, Klaus; Aranda, Jorge; Turner, Benjamin L; Marshall, John D

2007-01-01

The response of whole-plant water-use efficiency, termed transpiration efficiency (TE), to variation in soil fertility was assessed in a tropical pioneer tree, Ficus insipida Willd. Measurements of stable isotope ratios (delta(13)C, delta(18)O, delta(15)N), elemental concentrations (C, N, P), plant growth, instantaneous leaf gas exchange, and whole-plant water use were used to analyse the mechanisms controlling TE. Plants were grown individually in 19 l pots with non-limiting soil moisture. Soil fertility was altered by mixing soil with varying proportions of rice husks, and applying a slow release fertilizer. A large variation was observed in leaf photosynthetic rate, mean relative growth rate (RGR), and TE in response to experimental treatments; these traits were well correlated with variation in leaf N concentration. Variation in TE showed a strong dependence on the ratio of intercellular to ambient CO(2) mole fractions (c(i)/c(a)); both for instantaneous measurements of c(i)/c(a) (R(2)=0.69, P <0.0001, n=30), and integrated estimates based on C isotope discrimination (R(2)=0.88, P <0.0001, n=30). On the other hand, variations in the leaf-to-air humidity gradient, unproductive water loss, and respiratory C use probably played only minor roles in modulating TE in the face of variable soil fertility. The pronounced variation in TE resulted from a combination of the strong response of c(i)/c(a) to leaf N, and inherently high values of c(i)/c(a) for this tropical tree species; these two factors conspired to cause a 4-fold variation among treatments in (1-c(i)/c(a)), the term that actually modifies TE. Results suggest that variation in plant N status could have important implications for the coupling between C and water exchange in tropical forest trees.

Selecting native perennial plants for ecological intensification in Mediterranean greenhouse horticulture.

Science.gov (United States)

Rodríguez, E; González, M; Paredes, D; Campos, M; Benítez, E

2017-12-04

Natural control by predators and parasitoids provides an important and often unnoticed ecosystem service to agricultural landscapes by reducing pest populations in crops. The current model of horticultural intensification in south-eastern Spain produces high yields but has also resulted in a landscape almost completely covered by plastic. Promoting natural areas among greenhouses could enhance biodiversity, by being beneficial insects, and reduce pest pressure outdoors. The first step is to ascertain how pests and their natural enemies (NEs) use Mediterranean vegetation for selecting the best plants for pest suppression outdoors. The abundance of the two major horticultural pests, the tobacco whitefly, Bemisia tabaci, and the western flower thrips, Frankliniella occidentalis, together with their NEs, were assayed in 22 flowering perennial plants, which were newly planted in an experimental field surrounded by greenhouses. Eight plant species were identified as the most critical species for sustaining pest populations outdoors. A set of five plant species supported a medium level of pests, and another set of ten plant species supported the lowest level of both pests. Tobacco whitefly occurred in a few plants species, whereas western flower thrips occurred on almost all the plant species studied, and was favoured by the presence of flowers in perennial plants. The results suggest that plant diversity may provide relatively few acceptable host plants for tobacco whitefly than for western flower thrips. NEs were generally collected in plants that also supported abundance of pests, indicating that host/prey availability, more than food resources from flowers, was a stronger predictor of NE abundance in perennial plants. Field trials using the plants with the lowest host acceptance by pests are needed in order to ascertain whether pest abundance outdoors is reduced.

Aluminium exclusion and aluminium tolerance in woody plants

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Ivano eBrunner

2013-06-01

Full Text Available The aluminium (Al cation Al3+ is highly rhizotoxic and is a major stress factor to plants on acid soils, which cover large areas of tropical and boreal regions. Many woody plant species are native to acid soils and are well adapted to high Al3+ conditions. In tropical regions, both woody Al accumulator and non-Al accumulator plants occur, whereas in boreal regions woody plants are non-Al accumulators. The mechanisms of these adaptations can be divided into those that facilitate the exclusion of Al3+ from root cells (exclusion mechanisms and those that enable plants to tolerate Al3+ once it has entered the root and shoot symplast (internal tolerance mechanisms. The biochemical and molecular basis of these mechanisms have been intensively studied in several crop plants and the model plant Arabidopsis. In this review, we examine the current understanding of Al3+ exclusion and tolerance mechanisms from woody plants. In addition, we discuss the ecology of woody non-Al accumulator and Al accumulator plants, and present examples of Al3+ adaptations in woody plant populations. This paper complements previous reviews focusing on crop plants and provides insights into evolutionary processes operating in plant communities that are widespread on acid soils.

Aluminum exclusion and aluminum tolerance in woody plants.

Science.gov (United States)

Brunner, Ivano; Sperisen, Christoph

2013-01-01

The aluminum (Al) cation Al(3) (+) is highly rhizotoxic and is a major stress factor to plants on acid soils, which cover large areas of tropical and boreal regions. Many woody plant species are native to acid soils and are well adapted to high Al(3) (+) conditions. In tropical regions, both woody Al accumulator and non-Al accumulator plants occur, whereas in boreal regions woody plants are non-Al accumulators. The mechanisms of these adaptations can be divided into those that facilitate the exclusion of Al(3) (+) from root cells (exclusion mechanisms) and those that enable plants to tolerate Al(3) (+) once it has entered the root and shoot symplast (internal tolerance mechanisms). The biochemical and molecular basis of these mechanisms have been intensively studied in several crop plants and the model plant Arabidopsis. In this review, we examine the current understanding of Al(3) (+) exclusion and tolerance mechanisms from woody plants. In addition, we discuss the ecology of woody non-Al accumulator and Al accumulator plants, and present examples of Al(3) (+) adaptations in woody plant populations. This paper complements previous reviews focusing on crop plants and provides insights into evolutionary processes operating in plant communities that are widespread on acid soils.

Consistent patterns of high alpha and low beta diversity in tropical parasitic and free-living protists.

Science.gov (United States)

Lentendu, Guillaume; Mahé, Frédéric; Bass, David; Rueckert, Sonja; Stoeck, Thorsten; Dunthorn, Micah

2018-05-30

Tropical animals and plants are known to have high alpha diversity within forests, but low beta diversity between forests. By contrast, it is unknown whether microbes inhabiting the same ecosystems exhibit similar biogeographic patterns. To evaluate the biogeographies of tropical protists, we used metabarcoding data of species sampled in the soils of three lowland Neotropical rainforests. Taxa-area and distance-decay relationships for three of the dominant protist taxa and their subtaxa were estimated at both the OTU and phylogenetic levels, with presence-absence and abundance-based measures. These estimates were compared to null models. High local alpha and low regional beta diversity patterns were consistently found for both the parasitic Apicomplexa and the largely free-living Cercozoa and Ciliophora. Similar to animals and plants, the protists showed spatial structures between forests at the OTU and phylogenetic levels, and only at the phylogenetic level within forests. These results suggest that the biogeographies of macro- and micro-organismal eukaryotes in lowland Neotropical rainforests are partially structured by the same general processes. However, and unlike the animals and plants, the protist OTUs did not exhibit spatial structures within forests, which hinders our ability to estimate the local and regional diversity of protists in tropical forests. © 2018 John Wiley & Sons Ltd.

Selfing for the design of genomic selection experiments in biparental plant populations.

Science.gov (United States)

McClosky, Benjamin; LaCombe, Jason; Tanksley, Steven D

2013-11-01

Self-fertilization (selfing) is commonly used for population development in plant breeding, and it is well established that selfing increases genetic variance between lines, thus increasing response to phenotypic selection. Furthermore, numerous studies have explored how selfing can be deployed to maximal benefit in the context of traditional plant breeding programs (Cornish in Heredity 65:201-211,1990a, Heredity 65:213-220,1990b; Liu et al. in Theor Appl Genet 109:370-376, 2004; Pooni and Jinks in Heredity 54:255-260, 1985). However, the impact of selfing on response to genomic selection has not been explored. In the current study we examined how selfing impacts the two key aspects of genomic selection-GEBV prediction (training) and selection response. We reach the following conclusions: (1) On average, selfing increases genomic selection gains by more than 70 %. (2) The gains in genomic selection response attributable to selfing hold over a wide range population sizes (100-500), heritabilities (0.2-0.8), and selection intensities (0.01-0.1). However, the benefits of selfing are dramatically reduced as the number of QTLs drops below 20. (3) The major cause of the improved response to genomic selection with selfing is through an increase in the occurrence of superior genotypes and not through improved GEBV predictions. While performance of the training population improves with selfing (especially with low heritability and small population sizes), the magnitude of these improvements is relatively small compared with improvements observed in the selection population. To illustrate the value of these insights, we propose a practical genomic selection scheme that substantially shortens the number of generations required to fully capture the benefits of selfing. Specifically, we provide simulation evidence that indicates the proposed scheme matches or exceeds the selection gains observed in advanced populations (i.e. F 8 and doubled haploid) across a broad range of

Leaf quality and insect herbivory in model tropical plant communities after long-term exposure to elevated atmospheric CO2.

Science.gov (United States)

Arnone, J A; Zaller, J G; Körner, Ch; Ziegler, C; Zandt, H

1995-09-01

Results from laboratory feeding experiments have shown that elevated atmospheric carbon dioxide can affect interactions between plants and insect herbivores, primarily through changes in leaf nutritional quality occurring at elevated CO 2 . Very few data are available on insect herbivory in plant communities where insects can choose among species and positions in the canopy in which to feed. Our objectives were to determine the extent to which CO 2 -induced changes in plant communities and leaf nutritional quality may affect herbivory at the level of the entire canopy. We introduced equivalent populations of fourth instar Spodoptera eridania, a lepidopteran generalist, to complex model ecosystems containing seven species of moist tropical plants maintained under low mineral nutrient supply. Larvae were allowed to feed freely for 14 days, by which time they had reached the seventh instar. Prior to larval introductions, plant communities had been continuously exposed to either 340 μl CO 2 l -1 or to 610 μl CO 2 l -1 for 1.5 years. No major shifts in leaf nutritional quality [concentrations of N, total non-structural carbohydrates (TNC), sugar, and starch; ratios of: C/N, TNC/N, sugar/N, starch/N; leaf toughness] were observed between CO 2 treatments for any of the species. Furthermore, no correlations were observed between these measures of leaf quality and leaf biomass consumption. Total leaf area and biomass of all plant communities were similar when caterpillars were introduced. However, leaf biomass of some species was slightly greater-and for other species slightly less (e.g. Cecropia peltata)-in communities exposed to elevated CO 2 . Larvae showed the strongest preference for C. peltata leaves, the plant species that was least abundant in all communites, and fed relatively little on plants species which were more abundant. Thus, our results indicate that leaf tissue quality, as described by these parameters, is not necessarily affected by elevated CO 2 under

Seasonal changes in plant-water relations influence patterns of leaf display in Miombo woodlands: evidence of water conservative strategies.

Science.gov (United States)

Vinya, Royd; Malhi, Yadvinder; Brown, Nick D; Fisher, Joshua B; Brodribb, Timothy; Aragão, Luiz E O C

2018-06-15

Water availability has frequently been linked to seasonal leaf display in seasonally dry ecosystems, but there have been few ecohydrological investigations of this link. Miombo woodland is a dominant seasonally dry tropical forest ecosystem type in southern Africa; however, there are few data on the relationship between seasonal dynamics in plant-water relations and patterns of leaf display for Miombo woodland. Here we investigate this relationship among nine key Miombo woodland tree species differing in drought tolerance ability and leaf phenology. Results of this study showed that seasonal patterns of leaf phenology varied significantly with seasonal changes in stem water relations among the nine species. Leaf shedding coincided with the attainment of seasonal minimum stem water potential. Leaf flush occurred following xylem rehydration at the peak of the dry season suggesting that endogenous plant factors play a pivotal role in seasonal leaf display in this forest type. Drought-tolerant deciduous species suffered significantly higher seasonal losses in xylem hydraulic conductivity than the drought-intolerant semi-evergreen tree species (P water stress in seasonally dry tropical forests selects for water conservative traits that protect the vulnerable xylem transport system. Therefore, seasonal rhythms in xylem transport dictate patterns of leaf display in seasonally dry tropical forests.

A Hybrid Multiple-Criteria Decision-Making Approach for Photovoltaic Solar Plant Location Selection

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Amy H. I. Lee

2017-01-01

Full Text Available Due to decaying fossil resource and increasing environmental consciousness, the demand of renewable energy resources is escalating these days. Photovoltaic solar energy is one of the most popular renewable energy resources in places where sunlight is abundant. The selection of a desirable location for constructing a photovoltaic solar plant is the first and one of the most important stages in the plant construction to provide a long-term energy production. In this paper, a comprehensive multiple-criteria decision-making model, which incorporates the interpretive structural modeling (ISM, fuzzy analytic network process (FANP and VIKOR (VlseKriterijumska OptimizacijaI Kompromisno Resenje in Serbian,meaning multi-criteria optimization and compromise solution, is proposed to select the most suitable photovoltaic solar plant location. The ISM is applied first to determine the interrelationships among the criteria and among the sub-criteria,andtheresults are used to construct a decision-making network. The FANP is applied next to solve the network and to calculate the importance weights of the sub-criteria. Finally, the VIKOR is adopted to determine the ranking of the photovoltaic solar plant locations. The proposed model is applied in a case study in evaluating photovoltaic solar plant locations in Taiwan. By applying the proposed model, decision makers can have a better thinking process and make more appropriate decisions justifiably.

Frequency of Tropical Ocean Deep Convection and Global Warming

Science.gov (United States)

Aumann, H. H.; Behrangi, A.; Ruzmaikin, A.

2017-12-01

The average of 36 CMIP5 models predicts about 3K of warming and a 4.7% increase in precipitation for the tropical oceans with a doubling of the CO2 by the end of this century. For this scenario we evaluate the increase in the frequency of Deep Convective Clouds (DCC) in the tropical oceans. We select only DCC which reach or penetrate the tropopause in the 15 km AIRS footprint. The evaluation is based on Probability Distribution Functions (PDFs) of the current temperatures of the tropical oceans, those predicted by the mean of the CMIP5 models and the PDF of the DCC process. The PDF of the DCC process is derived from the Atmospheric Infrared Sounder (AIRS) between the years 2003 and 2016. During this time the variability due Enso years provided a 1 K p-p change in the mean tropical SST. The key parameter is the SST associated with the onset of the DCC process. This parameter shifts only 0.5 K for each K of warming of the oceans. As a result the frequency of DCC is expected to increases by the end of this century by about 50% above the current frequency.

Tropical forest carbon balance in a warmer world: a critical review spanning microbial- to ecosystem-scale processes

Science.gov (United States)

Wood, Tana E.; Cavaleri, Molly A.; Reed, Sasha C.

2012-01-01

, heterotrophic versus autotrophic respiration, thermal acclimation versus substrate limitation of plant and microbial communities, below-ground C allocation, species composition (plant and microbial), and the hydraulic architecture of roots. Whether or not tropical forests will become a source or a sink of C in a warmer world remains highly uncertain. Given the importance of these ecosystems to the global C budget, resolving this uncertainty is a primary research priority.

Nitrogen, phosphorus, and cation use efficiency in stands of regenerating tropical dry forest.

Science.gov (United States)

Waring, Bonnie G; Becknell, Justin M; Powers, Jennifer S

2015-07-01

Plants on infertile soils exhibit physiological and morphological traits that support conservative internal nutrient cycling. However, potential trade-offs among use efficiencies for N, P, and cations are not well explored in species-rich habitats where multiple elements may limit plant production. We examined uptake efficiency and use efficiency of N, P, K, Ca, Mg, Al, and Na in plots of regenerating tropical dry forests spanning a gradient of soil fertility. Our aim was to determine whether plant responses to multiple elements are correlated, or whether there are trade-offs among exploitation strategies across stands varying in community composition, soil quality, and successional stage. For all elements, both uptake efficiency and use efficiency decreased as availability of the corresponding element increased. Plant responses to N, Na, and Al were uncoupled from uptake and use efficiencies for P and essential base cations, which were tightly correlated. N and P use efficiencies were associated with shifts in plant species composition along the soil fertility gradient, and there was also a trend towards increasing N use efficiency with stand age. N uptake efficiency was positively correlated with the abundance of tree species that associate with ectomycorrhizal fungi. Taken together, our results suggest that successional processes and local species composition interact to regulate plant responses to availability of multiple resources. Successional tropical dry forests appear to employ different strategies to maximize response to N vs. P and K.

Drifting propagules and receding swamps: genetic footprints of mangrove recolonization and dispersal along tropical coasts.

Science.gov (United States)

Nettel, Alejandro; Dodd, Richard S

2007-04-01

Two issues that have captured the attention of tropical plant evolutionary biologists in recent years are the relative role of long distance dispersal (LDD) over vicariance in determining plant distributions and debate about the extent that Quaternary climatic changes affected tropical species. Propagules of some mangrove species are assumed to be capable of LDD due to their ability to float and survive for long periods of time in salt water. Mangrove species responded to glaciations with a contraction of their range. Thus, widespread mangrove species are an ideal system to study LDD and recolonization in the tropics. We present phylogenetic and phylogeographic analyses based on internal transcribed spacers region (ITS) sequences, chloroplast DNA (cpDNA), and amplified fragment length polymorphisms (AFLPs) of genomic DNA that demonstrate recent LDD across the Atlantic, rejecting the hypothesis of vicariance for the widespread distribution of the black mangrove (Avicennia germinans). Northern latitude populations likely became extinct during the late Quaternary due to frosts and aridification; these locations were recolonized afterward from southern populations. In some low latitude regions populations went extinct or were drastically reduced during the Quaternary because of lack of suitable habitat as sea levels changed. Our analyses show that low latitude Pacific populations of A. germinans harbor more diversity and reveal deeper divergence than Atlantic populations. Implications for our understanding of phylogeography of tropical species are discussed.

Fundamental plant biology enabled by the space shuttle.

Science.gov (United States)

Paul, Anna-Lisa; Wheeler, Ray M; Levine, Howard G; Ferl, Robert J

2013-01-01

The relationship between fundamental plant biology and space biology was especially synergistic in the era of the Space Shuttle. While all terrestrial organisms are influenced by gravity, the impact of gravity as a tropic stimulus in plants has been a topic of formal study for more than a century. And while plants were parts of early space biology payloads, it was not until the advent of the Space Shuttle that the science of plant space biology enjoyed expansion that truly enabled controlled, fundamental experiments that removed gravity from the equation. The Space Shuttle presented a science platform that provided regular science flights with dedicated plant growth hardware and crew trained in inflight plant manipulations. Part of the impetus for plant biology experiments in space was the realization that plants could be important parts of bioregenerative life support on long missions, recycling water, air, and nutrients for the human crew. However, a large part of the impetus was that the Space Shuttle enabled fundamental plant science essentially in a microgravity environment. Experiments during the Space Shuttle era produced key science insights on biological adaptation to spaceflight and especially plant growth and tropisms. In this review, we present an overview of plant science in the Space Shuttle era with an emphasis on experiments dealing with fundamental plant growth in microgravity. This review discusses general conclusions from the study of plant spaceflight biology enabled by the Space Shuttle by providing historical context and reviews of select experiments that exemplify plant space biology science.

Key role of symbiotic dinitrogen fixation in tropical forest secondary succession

NARCIS (Netherlands)

Batterman, S.A.; Hedin, L.O.; Breugel, van M.; Ransijn, J.; Craven, D.J.; Hall, J.S.

2013-01-01

Forests contribute a significant portion of the land carbon sink, but their ability to sequester CO2 may be constrained by nitrogen1, 2, 3, 4, 5, 6, a major plant-limiting nutrient. Many tropical forests possess tree species capable of fixing atmospheric dinitrogen (N2)7, but it is unclear whether

Chemoprophylaxis of Tropical Infectious Diseases

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William J. H. McBride

2010-05-01

Full Text Available Travelers to tropical countries are at risk for a variety of infectious diseases. In some cases effective vaccinations are available, but for other infections chemoprophylaxis can be offered. Malaria prevention has become increasingly complex as Plasmodium species become resistant to available drugs. In certain high risk settings, antibiotics can be used to prevent leptospirosis, scrub typhus and other infections. Post-exposure prophylaxis is appropriate for selected virulent infections. In this article the evidence for chemoprophylaxis will be reviewed.

Selective application of revised source terms to operating nuclear power plants

International Nuclear Information System (INIS)

Moon, Joo Hyun; Song, Jae Hyuk; Lee, Young Wook; Ko, Hyun Seok; Kang, Chang Sun

2001-01-01

More than 30 years later since 1962 when TID-14844 was promulgated, there has been big change of the US NRC's regulatory position in using accident source terms for radiological assessment following a design basis accident (DBA). To replace the instantaneous source terms of TID-14844, the time-dependent source terms of NUREG-1465 was published in 1995. In the meantime, the radiological acceptance criteria for reactor site evaluation in 10 CFR Part 100 were also revised. In particular, the concept of total effective dose equivalent has been incorporated in accordance with the radiation protection standards set forth in revised 10 CFR Part 20. Subsequently, the publication of Regulatory Guide 1.183 and the revision of Standard Review Plan 15.0.1 followed in 2000, which provided the licensee of operating nuclear power reactor with the acceptable guidance of applying the revised source term. The guidance allowed the holder of an operating license issued prior to January 10, 1997 to voluntarily revise the accident source terms used in the radiological consequence analyses of DBA. Regarding to its type of application, there suggested full and selective applications, Whether it is full or selective, based upon the scope and nature of associated plant modifications being proposed, the actual application of the revised source terms to an operating plant is expected to give a large impact on its facility design basis. Considering scope and cost of the analyses required for licensing, selective application is seemed to be more appealing to an licensee of the operating plant rather than full application. In this paper, hence, the selective application methodology is reviewed and is actally applied to the assessment of offsite radiological consequence following a LOCA at Ulchin Unit 3 and 4, in order to identify and analyze the potential impacts due to application of revised source terms and to assess the considerations taken in each application prior to its actual

Tree resin composition, collection behavior and selective filters shape chemical profiles of tropical bees (Apidae: Meliponini.

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Sara D Leonhardt

Full Text Available The diversity of species is striking, but can be far exceeded by the chemical diversity of compounds collected, produced or used by them. Here, we relate the specificity of plant-consumer interactions to chemical diversity applying a comparative network analysis to both levels. Chemical diversity was explored for interactions between tropical stingless bees and plant resins, which bees collect for nest construction and to deter predators and microbes. Resins also function as an environmental source for terpenes that serve as appeasement allomones and protection against predators when accumulated on the bees' body surfaces. To unravel the origin of the bees' complex chemical profiles, we investigated resin collection and the processing of resin-derived terpenes. We therefore analyzed chemical networks of tree resins, foraging networks of resin collecting bees, and their acquired chemical networks. We revealed that 113 terpenes in nests of six bee species and 83 on their body surfaces comprised a subset of the 1,117 compounds found in resins from seven tree species. Sesquiterpenes were the most variable class of terpenes. Albeit widely present in tree resins, they were only found on the body surface of some species, but entirely lacking in others. Moreover, whereas the nest profile of Tetragonula melanocephala contained sesquiterpenes, its surface profile did not. Stingless bees showed a generalized collecting behavior among resin sources, and only a hitherto undescribed species-specific "filtering" of resin-derived terpenes can explain the variation in chemical profiles of nests and body surfaces from different species. The tight relationship between bees and tree resins of a large variety of species elucidates why the bees' surfaces contain a much higher chemodiversity than other hymenopterans.

Assessment of materials selection and performance for direct-coal- liquefaction plants in the United States

Energy Technology Data Exchange (ETDEWEB)

Olsen, A.R.; Judkins, R.R.; Keiser, J.R.

1996-09-01

Several direct coal liquefaction processes have been demonstrated at the pilot plant level in the United States. Presently only one plant remains operational, namely, the Hydrocarbon Technologies, Inc., 4.0- ton-per-day process development unit in Lawrenceville, New Jersey. The period from 1974 to 1982 saw the greatest amount of development of direct coal liquefaction in the United States with four major pilot plants being devoted to variants of this technology. The plants included the SRC-I plant at Wilsonville, Alabama, which operated from 1974 to 1992; the SRC-I/II plant at Fort Lewis, Washington, which operated from 1974 to 1981; the H-Coal plant at Catlettsburg, Kentucky, which operated from 1980 to 1982; and the Exxon Coal Liquefaction Pilot Plant at Baytown, Texas, which operated from 1980 to 1982. Oak Ridge National Laboratory scientists and engineers were actively involved in many phases and technical disciplines at all four of these plants, especially in materials testing, evaluation, and failure analyses. In addition, ORNL materials scientists and engineers conducted reviews of the demonstration and commercial plant designs for materials selections. The ORNL staff members worked closely with materials engineers at the pilot plants in identifying causes of materials degradation and failures, and in identifying solutions to these problems. This report provides a comprehensive summary of those materials activities. Materials performance data from laboratory and coal liquefaction pilot plant tests, failure analyses, and analyses of components after use in pilot plants were reviewed and assessed to determine the extent and causes of materials degradation in direct coal liquefaction process environments. Reviews of demonstration and commercial plant design documents for materials selections were conducted. These reviews and assessments are presented to capture the knowledge base on the most likely materials of construction for direct coal liquefaction plants.

Properties of Soils and Plants Uptake within the Vicinity of Selected ...

African Journals Online (AJOL)

Backyard farming is becoming popular among the auto mechanics near their workshops where spent engine oil and carcass of vehicles are continuously dumped in Nigeria. The properties of soil and maize plants sampled from the vicinity of selected auto mechanic workshops in Ile-Ife, Nigeria were investigated. The results ...

Slow recovery of tropical old-field rainforest regrowth and the value and limitations of active restoration.

Science.gov (United States)

Shoo, Luke P; Freebody, Kylie; Kanowski, John; Catterall, Carla P

2016-02-01

There is current debate about the potential for secondary regrowth to rescue tropical forests from an otherwise inevitable cascade of biodiversity loss due to land clearing and scant evidence to test how well active restoration may accelerate recovery. We used site chronosequences to compare developmental trajectories of vegetation between self-organized (i.e., spontaneous) forest regrowth and biodiversity plantings (established for ecological restoration, with many locally native tree species at high density) in the Australian wet tropics uplands. Across 28 regrowth sites aged 1-59 years, some structural attributes reached reference rainforest levels within 40 years, whereas wood volume and most tested components of native plant species richness (classified by species' origins, family, and ecological functions) reached less than 50% of reference rainforest values. Development of native tree and shrub richness was particularly slow among species that were wind dispersed or animal dispersed with large (>10 mm) seeds. Many species with animal-dispersed seeds were from near-basal evolutionary lineages that contribute to recognized World Heritage values of the study region. Faster recovery was recorded in 25 biodiversity plantings of 1-25 years in which wood volume developed more rapidly; native woody plant species richness reached values similar to reference rainforest and was better represented across all dispersal modes; and species from near-basal plant families were better (although incompletely) represented. Plantings and regrowth showed slow recovery in species richness of vines and epiphytes and in overall resemblance to forest in species composition. Our results can inform decision making about when and where to invest in active restoration and provide strong evidence that protecting old-growth forest is crucially important for sustaining tropical biodiversity. © 2015 Society for Conservation Biology.

EFFECT OF SELECTED PETROLEUM-DERIVED SUBSTANCES ON BRUCHUS RUFIMANUS BOH. FEEDING AND ON SELECTED MORPHOLOGICAL CHARACTERISTICS OF PLANTS

Directory of Open Access Journals (Sweden)

Milena Rusin

2015-10-01

Full Text Available The aim of the study was to determine the effect of petrol, used engine oil and diesel oil on Bruchus rufimanus Boh. feeding and on selected morphological characteristics of plants. In addition, the effect of bioremediation process on the above mentioned features was examined. Pest’s feeding intensity assessment was carried out by determining the number of damaged seeds and their weight. Assessment of morphological characteristics of plants was made in the technological maturity of broad bean seeds. The results of the experiment showed that all substances used in the experiment had no significant effect on B. rufimanus Boh feeding. Diesel oil most adversely affected the analyzed morphological characteristics. Applied bioremediation caused a decrease the mass of seeds developed by plant and the number of damaged seeds in the object contaminated with petrol and contributed to the increase in the number and weight of pods and the number of seeds per one plant in the object contaminated with diesel oil.