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991.
Activity-guided fractionation of the methanol extract of Ebenus pinnata aerial parts led to the isolation of ombuoside (1), kaempferol 3-O-rutinoside (2), rutin (3), catechin (4), and picein (5), along with beta-sitosterol and beta-sitosterol glucoside. Compounds 1-4 showed significant antioxidant activity in the DPPH, and TEAC, reducing power assays.  相似文献   
992.
  • ? The objective of this work is the molecular characterization of most common identified morphotypes of critically endangered rare Moroccan species Argania spinosa.
  • ? Eighteen RAPD markers and twenty SSR markers have been assayed in 38 argan tree accessions from the three most commonly identified morphotypes: oval, spherical and spindle fruit types.
  • ? A total of 140 polymorphic RAPD bands were detected out of 146 bands. The number of presumed alleles revealed by the SSR analysis ranged from 1 to 5 alleles per locus with a total number of 32 alleles identified. Results demonstrated an extensive genetic variability within the tested argan accessions. RAPDs presented a high level of polymorphism and greater information content than SSRs.
  • ? Our results could indicate that Vitellaria paradoxa is genetically closer to argan than Manilkara huberi. In addition, the correlation between the clustering based on RAPD and SSR markers were in general low. The observed clustering could be better explained according to geographic proximity than morphotype. For this reason the traditional morphological characterization of the argan accessions in morphotypes (according to fruit phenotype) seem not to be in correlation to the real genetic background (genotype) of this specie. The implications of these results in the creation of effective germplasm core collection in argan have been also discussed.
  •   相似文献   
    993.
    The goal of this study was to assess the water status variability of a commercial rain-fed Tempranillo vineyard (Vitis vinifera L.) by thermal and multispectral imagery using an unmanned aerial vehicle (UAV). The relationships between aerial temperatures or indices derived from the imagery and leaf stomatal conductance (g s) and stem water potential (Ψstem) were determined. Aerial temperature was significantly correlated with g s (R 2?=?0.68, p?<?0.01) and Ψstem (R 2?=?0.50, p?<?0.05). Furthermore, the thermal indices derived from aerial imagery were also strongly correlated with Ψstem and g s. Moreover, different spectral indices were related to vineyard water status, although NDVI (normalized difference vegetation index) and TCARI/OSAVI (ratio between transformed chlorophyll absorption in reflectance and optimized soil-adjusted vegetation index) showed the highest coefficient of determination with Ψstem (R 2?=?0.68, p?<?0.05) and g s (R 2?=?0.84, p?<?0.05), respectively. While the relationship with thermal imagery and water status parameters could be considered as a short-term response, NDVI and TCARI/OSAVI indices were probably reflecting the result of cumulative water deficits, hence a long-term response. In conclusion, thermal and multispectral imagery using an UAV allowed assessing and mapping spatial variability of water status within the vineyard.  相似文献   
    994.
    995.
    Insects of the orders Ephemeroptera, Plecoptera, and Trichoptera (EPT) are often used to assess the conditions of aquatic environments, but few studies have examined the differences in these communities between riffles and pools. Our objective was to test whether riffles shelter greater richness and abundance of EPT, as well as to assess the sensitivity of these insects for detecting impacts from different land uses in streams in southeastern Brazil. Samples were collected in the dry season of 2012 with a Surber sampler in riffles and pools of nine streams (forest, pasture, and urban areas). Principal component analysis distinguished the streams according to different land uses as a function of percentage of plant cover and water oxygenation level and showed partial distinction between riffles and pools as a function of current speed and percentage of ultrafine sand. Detrended correspondence analysis indicated the distinction in EPT composition between riffles and pools, except in urban streams. The results of this study confirm the expected differences in the EPT fauna structure between riffles and pools, especially in forest and pasture environments. The individual metrics of riffle and pool assemblages showed significantly different responses to land use. Therefore, we suggest individual sampling of riffles and pools, since the metrics of these assemblages’ insects can differ between these habitats and influence the results of assessments in low-order streams.  相似文献   
    996.
    A high incidence of plants with mosaic, chlorotic spots, ringspots, necrosis, smaller leaves, and stunting was observed on peanut crops (Arachis hypogaea L.) in Itápolis, São Paulo State, Brazil. Transmission electron microscope examination of thin sections of infected leaves revealed the presence of spheroidal particles, ca. 80 nm in diameter, suggestive of Tospovirus. A DNA fragment of ~600 bp was amplified by RT-PCR from total RNA extracted from infected tissues using primers specific for the nucleocapsid gene of Groundnut ringspot virus (GRSV). Nucleotide and deduced amino acid sequences of the fragments showed high identities with known GRSV isolates.  相似文献   
    997.
    998.
    Animals have developed a range of drinking strategies depending on physiological and environmental constraints. Vertebrates with incomplete cheeks use their tongue to drink; the most common example is the lapping of cats and dogs. We show that the domestic cat (Felis catus) laps by a subtle mechanism based on water adhesion to the dorsal side of the tongue. A combined experimental and theoretical analysis reveals that Felis catus exploits fluid inertia to defeat gravity and pull liquid into the mouth. This competition between inertia and gravity sets the lapping frequency and yields a prediction for the dependence of frequency on animal mass. Measurements of lapping frequency across the family Felidae support this prediction, which suggests that the lapping mechanism is conserved among felines.  相似文献   
    999.
  • ? The use of landscape indices in the analysis of forest landscapes offers great potential for integration of spatial pattern information in management processes, but requires understanding of the limitations and correct interpretation of results. In this sense, awareness of scale effects on landscape indices is essential, especially when the data available is restricted to low-resolution maps.
  • ? In this study, developed within the framework of the FORSEE project, the objective was to define accurately the potential usefulness of applying landscape indices to low-resolution maps commonly used in forestry studies. Landscape indices were applied to two maps differing in spatial resolution, and subsets were defined for three spatial extensions. Correlation analysis and comparison of the results were carried out to enable identification of the most suitable indices for use with low resolution data.
  • ? The analysis enabled identification of the least scale-dependent indices, which are thus more useful for extrapolating results from low-resolution data. In general terms, diversity and edge indices provided the best results.
  • ? We conclude that some (but not all) of the landscape indices can be used to analyse low-resolution maps with acceptable results. Additional advice is made to prevent misuse of the application of landscape indices.
  •   相似文献   
    1000.
    Developmental thresholds and thermal requirements for development of post-dormancy larvae of Monochamus galloprovincialis (Olivier) (Cerambycidae; Monochamini) were studied at ten constant temperatures ranging from 7 to 35°C. The relationship between temperature and development duration in days was linear between 15 and 30°C (r 2  = 0.98). The lower threshold for development was determined to be 12.2 ± 0.8°C and an average of 822 degree-days (DD) above that value was required for 50% adult emergence under laboratory conditions. The rate of larval development decreased above 30°C and the lethal upper threshold was between 32 and 35°C. Degree-day rate summation was initiated in the first of March and model predictions were validated with records of field emergence for the years 2001 to 2004. The modified sine wave predicted median emergence with an average error of 3.8 days from emergences in the field and a zero-day difference for two of the years. Model predictions were always within 10% of actual observed emergences. Predictions for early emergences (cumulative percentiles 1 and 10) were less accurate than predictions for median and late emergencies. The results suggest that a simple linear method driven by air temperatures can predict the emergence of M. galloprovincialis with sufficient accuracy to improve the pest management programmes currently implemented on the pine wilt disease affected zone in Portugal.  相似文献   
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