Biochemical traits useful for the determination of genetic variation in a natural population of Myracrodruon urundeuva

The objectives of this work were to analyze seeds from 20 trees of aroeira (Myracrodruon urundeuva Fr. All.) of a natural population located in the region of Selvíria, State of Mato Grosso do Sul, Brazil, in order to evaluate their protein, lipid and carbohydrate contents, and to estimate their genetic variation. A completely randomized experimental design consisting of 20 treatments (families) was set up, with two replications. Four types of proteins were detected: albumin (35.0 to 107.3 mg/g seed), globulin (3.4 to 9.3 mg/g), prolamin (60.0 to 135.2 mg/g) and glutelin (118.0 to 286.0 mg/g). The lipid content varied between 200 and 334 mg/g seed. The total sugars also varied (26.5 to 46.3 mg/g seed), with a predominance of polyols (arabinitol, mannitol, glucitol and xylitol). The main monosaccharides detected were glucose and arabinose. Total hydrolysis of the sugars indicated the presence of neutral arabinan and xylan oligosaccharides. The starch content varied from 0.35 to 1.58 mg/g seed. These biochemical traits showed considerable genetic variability, indicating that only the collection of seeds from many different trees can provide a representative sample of the population for conservation and genetic improvement.

Integration or individuation : are the salvation goods promised by first-century Christian preaching still attractive ?

(Résumé de l'ouvrage) The idea that religion has to succeed in a «market», selling «salvation goods», has proved to be extremely attractive to scholars in sociology and the study of religion. Max Weber used the term «salvation good» to compare different religious traditions. Pierre Bourdieu employed the term in order to analyze «religious economy». And recently, an American group of researchers advocating «rational choice of religion» put the theme at the forefront of current debates. This book - the fruit of an International Congress in Lausanne in April 2005 - brings together leading specialists in the fields of sociology and the study of religion who discuss the terms «salvation goods» (or religious goods) and «religious market». The authors test the applicability of these concepts by using specific examples and they either deliberately advocate or criticize Weberian, Bourdieusian or rational-choice perspectives.

Predicting current and future spatial community patterns of plant functional traits

Community-level patterns of functional traits relate to community assembly and ecosystem functioning. By modelling the changes of different indices describing such patterns - trait means, extremes and diversity in communities - as a function of abiotic gradients, we could understand their drivers and build projections of the impact of global change on the functional components of biodiversity. We used five plant functional traits (vegetative height, specific leaf area, leaf dry matter content, leaf nitrogen content and seed mass) and non-woody vegetation plots to model several indices depicting community-level patterns of functional traits from a set of abiotic environmental variables (topographic, climatic and edaphic) over contrasting environmental conditions in a mountainous landscape. We performed a variation partitioning analysis to assess the relative importance of these variables for predicting patterns of functional traits in communities, and projected the best models under several climate change scenarios to examine future potential changes in vegetation functional properties. Not all indices of trait patterns within communities could be modelled with the same level of accuracy: the models for mean and extreme values of functional traits provided substantially better predictive accuracy than the models calibrated for diversity indices. Topographic and climatic factors were more important predictors of functional trait patterns within communities than edaphic predictors. Overall, model projections forecast an increase in mean vegetation height and in mean specific leaf area following climate warming. This trend was important at mid elevation particularly between 1000 and 2000 m asl. With this study we showed that topographic, climatic and edaphic variables can successfully model descriptors of community-level patterns of plant functional traits such as mean and extreme trait values. However, which factors determine the diversity of functional traits in plant communities remains unclear and requires more investigations.

Polyembryony and identification of Volkamerian lemon zygotic and nucellar seedlings using RAPD

The objectives of this work were to evaluate the frequency of polyembryony, and to identify zygotic and nucellar seedlings of Citrus volkameriana using RAPD. Twenty-five polyembryonic and eight monoembryonic seeds were cultivated in vitrofor six months. DNA from seedlings was extracted and used in combination with five RAPD primers to identify zygotic or nucellar origin of the seedlings. Environmental conditions of the year affected significantly (P<0.05) the morphological characteristics of fruitsand the number ofembryos per seed. Polyembryonic seeds ranged from 30.9%, 44.8% to 54.4% over three years. Morphological characteristic was not correlated with polyembryony. In vitro culture enable all embryos of each seed to grow, favoring the percentage of seedlings identified as zygotic. In polyembryonic and monoembryonic seeds, 25.9% and 87.5% of the seedlings, respectively, were sexually originated. In polyembryonic seeds, not all zygotic seedlings were produced by small embryos located at the micropyle.

Lipoxygenase activities during development of root and nodule of soybean

The objective of this work was to evaluate root and nodule soybean lipoxygenases in Doko cultivar and in a near isogenic line lacking seed lipoxygenases, inoculated and uninoculated with Bradyrhizobium elkanii. The lipoxygenase activities from roots collected at 3, 5, 9, 13, 18 and 28 days post-inoculation and from nodules collected at 13, 18 and 28 days post-inoculation were measured. The pH-activity profiles from root and nodules suggested that the lipoxygenases pool expressed in these organs from Doko cultivar and triple-null near isogenic lines are similar. The root lipoxygenase activity of Doko and triple-null lines, inoculated and uninoculated, reduced over time. The highest lipoxygenase activity observed at the beginning of root formation suggests the involvement of this enzyme in growth and development of this organ. However, for nodules an expressive increase of lipoxygenase activity was noticed 28 days post-inoculation. Root and nodule showed, at least, two mobility groups for lipoxygenases in immunoblottings, with approximately 94 and 97 kDa.

Effect of neem extract on the cotton aphid

The aphid Aphis gossypii Glover (Hemiptera: Aphididae), a harmful pest on cotton, causes direct damage, reducing plant vigor, and indirect damage by honeydew secretion and transmission of several viruses. Due to the problem of pesticide resistance, alternative techniques for chemical control, such as the use of natural insecticides, have been object of research. The effects of aqueous extracts of neem (Azadirachta indica A. Juss) seed powder on the development, survival and fecundity of A. gossypii were evaluated. Treatments consisted of neem seed powder in the concentrations of 23.8, 122.0, 410.0 and 1,410.0 mg/100 mL of distilled water. Mortality rate during the nymphal development for aphids maintained on cotton leaf discs treated with the two highest concentrations were, respectively, 60.0% and 100.0%. With the exception of the highest concentration (1,410.0 mg/100 mL), neem concentrations did not extend the aphids' development period. The net reproductive rate (R0) was of 35.0 nymphs/female for control aphids and of 0.0 nymph/female when the group of females was exposed to neem seed powder at 1,410.0 mg/100 mL since birth. The aqueous extract of neem seeds is efficient against the aphid A. gossypii, causing nymph mortality and reducing their survival period and fecundity.

Logging versus fire : how does disturbance type influence the abundance of Pinus strobus regeneration?

Abstract

Isozymic variability in a Brazilian collection of annatto (Bixa orellana L.)

The objectives of this work were to optimize the isozyme electrophoresis technique for Bixa orellana, and use isozyme markers for a preliminary survey on the genetic variability in Brazilian annatto germplasm accessions. Collection consisted of seed samples from sixty open pollinated trees, representing two Northern and four Southern geographic provenances. The extraction, electrophoresis, and interpretation of annatto isozymes are described. Three out of the twenty-one identified isozyme loci were polymorphic in the collection. The percentage of polymorphic loci (P = 21.05) and the expected heterozygosity in annatto (H T = 0.064) were low, compared to other tropical woody species. A UPGMA phenogram, constructed with Nei's genetic distances, clearly separated the germplasm provenant from North and Central Brazil. Variability was significantly higher among the accessions from Maranhão. A sharp genetic differentiation was detected between accessions from Maranhão and Pará States, despite their geographical proximity. The distinctive isozyme polymorphism, observed in the accessions from Maranhão, together with reports on local morphological heterogeneity in annatto fruit shape, color, and pubescence, calls for more detailed genetic and taxonomic investigation.

Characterization of OsMIK in a rice mutant with reduced phytate content reveals an insertion of a rearranged retrotransposon.

The rice low phytic acid (lpa) mutant Os-lpa-XS110-1(XS-lpa) has ~45 % reduction in seed phytic acid (PA) compared with the wild-type cultivar Xiushui 110. Previously, a single recessive gene mutation was shown to be responsible for the lpa phenotype and was mapped to a region of chromosome 3 near OsMIK (LOC_Os03g52760) and OsIPK1 (LOC_Os03g51610), two genes involved in PA biosynthesis. Here, we report the identification of a large insert in the intron of OsMIK in the XS-lpa mutant. Sequencing of fragments amplified through TAIL-PCRs revealed that the insert was a derivative of the LINE retrotransposon gene LOC_Os03g56910. Further analyses revealed the following characteristics of the insert and its impacts: (1) the inserted sequence of LOC_Os03g56910 was split at its third exon and rejoined inversely, with its 5' and 3' flanking sequences inward and the split third exon segments outward; (2) the LOC_Os03g56910 remained in its original locus in XS-lpa, and the insertion probably resulted from homologous recombination repair of a DNA double strand break; (3) while the OsMIK transcripts of XS-lpa and Xiushui 110 were identical, substantial reductions of the transcript abundance (~87 %) and the protein level (~60 %) were observed in XS-lpa, probably due to increased methylation in its promoter region. The above findings are discussed in the context of plant mutagenesis, epigenetics and lpa breeding.

Analysis of preharvest sprouting in three Brazilian wheat populations

The objective of this work was to evaluate the possibility of obtaining recombinant inbred wheat lines more resistant to preharvest sprouting, independently of colour genes, in three red-grained Brazilian wheat populations. The results showed statistical significance among lines within all populations, which presented a normal distribution and transgressive segregation for preharvest sprouting. The normal distribution of the lines from all red-grained populations suggests that sprouting, excluding the genes expressing seed coat pigmentation, is, probably, controlled by many genes. These findings also indicate that it may be possible to improve resistance to preharvest sprouting, independently of the colour genes.

Prediction of cottonseed longevity

The objective of this work was to determine the viability equation constants for cottonseed and to detect the occurrence and depletion of hardseededness. Three seedlots of Brazilian cultivars IAC-19 and IAC-20 were tested, using 12 moisture content levels, ranging from 2.2 to 21.7% and three storage temperatures, 40, 50 and 65ºC. Seed moisture content level was reached from the initial value (around 8.8%) either by rehydration, in a closed container, or by drying in desiccators containing silica gel, both at 20ºC. Twelve seed subsamples for each moisture content/temperature treatment were sealed in laminated aluminium-foil packets and stored in incubators at those temperatures, until complete survival curves were obtained. Seed equilibrium relative humidity was recorded. Hardseededness was detected at moisture content levels below 6% and its releasing was achieved either naturally, during storage period, or artificially through seed coat removal. The viability equation quantified the response of seed longevity to storage environment well with K E = 9.240, C W = 5.190, C H = 0.03965 and C Q = 0.000426. The lower limit estimated for application of this equation at 65ºC was 3.6% moisture content.

Electrical conductivity testing of corn seeds as influenced by temperature and period of storage

The objective of this work was to evaluate the effects of temperature (10, 20, 30, 20/10 and 30/10ºC) and period of storage on electrical conductivity (EC) in four seed lots of corn (Zea mays L.), as well as the mineral composition of the soaking solution. EC test determines indirectly the integrity of seed membrane systems, and is used for the assessment of seed vigor, because this test detects the seed deterioration process since its early phase. The research comprised determinations of water content, germination, accelerated aging (AA), cold (CT) and EC vigor tests, and determinations of Ca2+, Mg2+ and K+ release to the solution, after seed soaking of four corn seed lots. The evaluations were performed each four months during a period of 16 months. For statistical analysis, a completely randomized split plot design was used with eight replications. Except for seed lots stored at 10ºC, all vigor evaluations revealed a decline in vigor, but AA and CT showed more sensitiveness to declines of seed physiological quality than EC. Potassium was the main leached ion regardless of the storage temperature.

Seed viability constants for Eucalyptus grandis

This work aimed to analyse Eucalyptus grandis W.Hill ex Maiden seed behaviour, under controlled deterioration, and to estimate viability equation constants for the species. Seeds were harvested in the growing season of 1999, and the moisture contents were adjusted from 11.3% to a range between 1.2 and 18.1% at 25ºC. The subsamples were sealed into laminate aluminium-foil packets, for storage in incubators at 40, 50 and 65±0.5ºC. The seeds presented orthodox performance, in which the constants for predicting seed longevity of E. grandis were K E = 9.661, C W = 6.467, C H = 0.03498 and C Q = 0.0002330. The usual and inverse relationship between water content and seed longevity was also observed. The lowest moisture content limit for application of the viability equation at 65ºC was 4.9%, estimated under hygroscopic equilibrium with 23% of relative humidity in the storage environment.

Providing more informative projections of climate change impact on plant distribution in a mountain environment

Summary Due to their conic shape and the reduction of area with increasing elevation, mountain ecosystems were early identified as potentially very sensitive to global warming. Moreover, mountain systems may experience unprecedented rates of warming during the next century, two or three times higher than that records of the 20th century. In this context, species distribution models (SDM) have become important tools for rapid assessment of the impact of accelerated land use and climate change on the distribution plant species. In my study, I developed and tested new predictor variables for species distribution models (SDM), specific to current and future geographic projections of plant species in a mountain system, using the Western Swiss Alps as model region. Since meso- and micro-topography are relevant to explain geographic patterns of plant species in mountain environments, I assessed the effect of scale on predictor variables and geographic projections of SDM. I also developed a methodological framework of space-for-time evaluation to test the robustness of SDM when projected in a future changing climate. Finally, I used a cellular automaton to run dynamic simulations of plant migration under climate change in a mountain landscape, including realistic distance of seed dispersal. Results of future projections for the 21st century were also discussed in perspective of vegetation changes monitored during the 20th century. Overall, I showed in this study that, based on the most severe A1 climate change scenario and realistic dispersal simulations of plant dispersal, species extinctions in the Western Swiss Alps could affect nearly one third (28.5%) of the 284 species modeled by 2100. With the less severe 61 scenario, only 4.6% of species are predicted to become extinct. However, even with B1, 54% (153 species) may still loose more than 80% of their initial surface. Results of monitoring of past vegetation changes suggested that plant species can react quickly to the warmer conditions as far as competition is low However, in subalpine grasslands, competition of already present species is probably important and limit establishment of newly arrived species. Results from future simulations also showed that heavy extinctions of alpine plants may start already in 2040, but the latest in 2080. My study also highlighted the importance of fine scale and regional. assessments of climate change impact on mountain vegetation, using more direct predictor variables. Indeed, predictions at the continental scale may fail to predict local refugees or local extinctions, as well as loss of connectivity between local populations. On the other hand, migrations of low-elevation species to higher altitude may be difficult to predict at the local scale. Résumé La forme conique des montagnes ainsi que la diminution de surface dans les hautes altitudes sont reconnues pour exposer plus sensiblement les écosystèmes de montagne au réchauffement global. En outre, les systèmes de montagne seront sans doute soumis durant le 21ème siècle à un réchauffement deux à trois fois plus rapide que celui mesuré durant le 20ème siècle. Dans ce contexte, les modèles prédictifs de distribution géographique de la végétation se sont imposés comme des outils puissants pour de rapides évaluations de l'impact des changements climatiques et de la transformation du paysage par l'homme sur la végétation. Dans mon étude, j'ai développé de nouvelles variables prédictives pour les modèles de distribution, spécifiques à la projection géographique présente et future des plantes dans un système de montagne, en utilisant les Préalpes vaudoises comme zone d'échantillonnage. La méso- et la microtopographie étant particulièrement adaptées pour expliquer les patrons de distribution géographique des plantes dans un environnement montagneux, j'ai testé les effets d'échelle sur les variables prédictives et sur les projections des modèles de distribution. J'ai aussi développé un cadre méthodologique pour tester la robustesse potentielle des modèles lors de projections pour le futur. Finalement, j'ai utilisé un automate cellulaire pour simuler de manière dynamique la migration future des plantes dans le paysage et dans quatre scénarios de changement climatique pour le 21ème siècle. J'ai intégré dans ces simulations des mécanismes et des distances plus réalistes de dispersion de graines. J'ai pu montrer, avec les simulations les plus réalistes, que près du tiers des 284 espèces considérées (28.5%) pourraient être menacées d'extinction en 2100 dans le cas du plus sévère scénario de changement climatique A1. Pour le moins sévère des scénarios B1, seulement 4.6% des espèces sont menacées d'extinctions, mais 54% (153 espèces) risquent de perdre plus 80% de leur habitat initial. Les résultats de monitoring des changements de végétation dans le passé montrent que les plantes peuvent réagir rapidement au réchauffement climatique si la compétition est faible. Dans les prairies subalpines, les espèces déjà présentes limitent certainement l'arrivée de nouvelles espèces par effet de compétition. Les résultats de simulation pour le futur prédisent le début d'extinctions massives dans les Préalpes à partir de 2040, au plus tard en 2080. Mon travail démontre aussi l'importance d'études régionales à échelle fine pour évaluer l'impact des changements climatiques sur la végétation, en intégrant des variables plus directes. En effet, les études à échelle continentale ne tiennent pas compte des micro-refuges, des extinctions locales ni des pertes de connectivité entre populations locales. Malgré cela, la migration des plantes de basses altitudes reste difficile à prédire à l'échelle locale sans modélisation plus globale.

MGS Esmeralda: new large seed mungbean cultivar

Mungbean cultivar MGS Esmeralda was developed by Asian Vegetable Research and Development Center (Shanhua, Taiwan), as a result of crossing between the lines VC 1973A and VC 2768A. In ten trials conducted in the State of Minas Gerais, Brazil, it produced 13.5% more grains than 'Ouro Verde MG-2' (control cultivar), and its highest yield was 2,550 kg ha-1. The cultivar MGS Esmeralda is more susceptible to lodging, and its pods mature more uniformly than Ouro Verde MG-2 pods. One hundred-seed mass of 'MGS Esmeralda' ranged between 5.5 and 6.8 g. Both cultivars are susceptible to powdery mildew and cercospora leaf spot.