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91.
Pedro Talhinhas José Leitão João Neves-Martins 《Genetic Resources and Crop Evolution》2006,53(3):563-578
Lupinus angustifolius L. is a Mediterranean species, domesticated in the 20th century, representing an important grain legume crop in Australia
and other countries. This work is focused on the collection of wild germplasm and on the characterisation of morphological
and molecular diversity of germplasm accessions. It reports the collection of 81 wild L. angustifolius accessions from the South and Centre of Portugal, available at the ‘Instituto Superior de Agronomia Gene Bank’, with subsequent
morphological and molecular characterisation of a selection of these and other accessions. A multivariate analysis of morphological
traits on 88 L. angustifolius accessions (including 59 wild Portuguese accessions, 15 cultivars and 14 breeding lines) showed a cline of variation on wild
germplasm, with plants from Southern Portugal characterised by earlier flowering, higher vegetative development and larger
seeds. AFLP and ISSR molecular markers grouped modern cultivars as sub-clusters within the wider diversity of wild germplasm,
revealing the narrow pool of genetic diversity on which domesticated accessions are based. The importance of preserving, characterising
and using wild genetic resources for L. angustifolius crop improvement is outlined by the results obtained. 相似文献
92.
Pedro M. Antunes Amarilis de Varennes Michael J. Goss 《Soil biology & biochemistry》2006,38(6):1234-1242
This study is the first report assessing the effect of soil inoculation on the signalling interaction of Bradyrhizobium japonicum, arbuscular mycorrhizal fungi (AMF) and soybean plants throughout the early stages of colonisation that lead to the tripartite symbiosis. In a study using soil disturbance to produce contrasting indigenous AMF treatments, the flavonoids daidzein, genistein and coumestrol were identified as possible signals for regulating the establishment of the tripartite symbiosis. However, it was unclear whether soil disturbance induced changes in flavonoid root accumulation other than through changing the potential for AMF colonization. In this study, soil treatments comprising all possible combinations of AMF and B. japonicum were established to test whether (1) modifications in root flavonoid accumulation depend on the potential for AMF colonization, and (2) synthesis and accumulation of flavonoids in the roots change over time as a function of the early plant-microbial interactions that lead to the tripartite symbiosis. The study was comprised of two phases. First, maize was grown over 3-week periods to promote the development of the AM fungus Glomus clarum. Second, the interaction between soybean, G. clarum and B. japonicum was evaluated at 6, 10, 14 and 40 days after plant emergence. Root colonization by G. clarum had a positive effect on nodulation 14 days after emergence, producing, 30% more nodules which were 40% heavier than those on roots solely inoculated with B. japonicum. The tripartite symbiosis resulted in 23% more N2 being fixed than did the simpler symbiosis between soybean and B. japonicum. The presence of both symbionts changed accumulation of flavonoids in roots. Daidzein and coumestrol increased with plant growth. However, development of the tripartite symbiosis caused a decrease in coumestrol; accumulation of daidzein, the most abundant flavonoid, was reduced in the presence of AMF. 相似文献
93.
EL-Habib Dakir María-Luisa Ruiz Pedro García Marcelino Pérez de la Vega 《Genetic Resources and Crop Evolution》2002,49(6):619-631
The genetic variation existing in a set of barley (Hordeum vulgare L.) landrace samples recently collected in Morocco was estimated. Two kinds of genetic markers, seed storage proteins (hordeins) and random amplified polymorphic DNA (RAPD), were used. Only six out of 31 landraces were subjected to RAPD analysis. Both kinds of markers, RAPD and storage proteins, yielded similar results, showing that the level of variation observed in Moroccan barley was high: all landraces showed variability; 808 different storage protein patterns (multilocus associations) were observed among 1897 individuals (2.32 seeds per association, on average) with an average of 43 multilocus associations per accession. In general, genetic variation within accessions was higher than between accessions. The 100 polymorphic RAPD bands generated by 21 effective primers were able to generate enough patterns to differentiate between uniform cultivars and even between individuals in variable accessions. One of the aims of this work was to compare the effectiveness of RAPD versus storage protein techniques in assessing the variability of genetic resource collections. On average hordeins were more polymorphic than RAPDs: they showed more alternatives per band on gels and a higher percentage of polymorphic bands, although RAPDs supply a higher number of bands. Although RAPD is an easy and standard technique, storage protein analysis is technically easier, cheaper and needs less sophisticated equipment. Thus, when resources are a limiting factor and considering the cost of consumables and work time, seed storage proteins must be the technique of choice for a first estimation of genetic variation in plant genetic resource collections. 相似文献
94.
Gabriela Diosma Mnica Aulicino Hugo Chidichimo Pedro A. Balatti 《Soil & Tillage Research》2006,91(1-2):236-243
Microbial diversity might be a good indicator of ecosystem disturbance and functioning. We determined the effect of soil disturbances, such as N fertilization and tillage management, on soil microbial communities in a Typic Argiudoll of the El Salado river basin (Argentina). Microbial activity and substrate utilization provided a metabolic fingerprint of the soil microbial community. Univariate and multivariate analyses were used to differentiate responses to N fertilization and tillage at each of three growth stages of wheat (Triticum aestivum L.). Tillage had an adverse effect on microbial diversity, in which reduced and conventional tillage treated soils had different populations. However, N fertilization also altered microbial diversity depending on the crop developmental stage considered. Metabolism of carboxylic acids and carbohydrates were the main indicators of functional microbial activity and diversity. Although the substrate consumption profile of 32 C substrates did not provide insights into the fundamental ecological interactions that may induce changes in microbial population, it allowed us to demonstrate the alterations of microbial diversity as a result of tillage. We conclude that tillage and N fertilization altered microbial diversity. 相似文献
95.
Ninety four accessions of the cultivated triploid potatoS. chaucha were analyzed and classified in genotypic groups using 9 isozyme loci and RAPD markers disclosed by 20 arbitrary 10-mer primers.
Eight isozyme loci out of nine were polymorphic. A total of 22 allozymes were analyzed but none of them were specific for
any genotypic group. About half (52%) of the 102 RAPD markers scored, were polymorphic, all of them showing polymorphism among
groups and rarely within groups. Eighteen RAPD markers were specific for certain genotypes. The isozyme markers showed a certain
amount of intra group variation which made classification less reliable than with RAPD markers. A total of 10 triploid genetic
groups were discriminated using both techniques together. A single primer was found to be sufficient to distinguish all 10
groups. All varieties of a single group are considered to have been derived from the same cross and then clonally propagated,
even though there is a high amount of morphological variation within a single genotypic group due probably to somatic mutations.
RAPD markers have been shown to be more reliable in the classification of triploid potato varieties than other genetic markers
like isozymes, proteins and morphological traits. 相似文献
96.
Fermin Rivera M. Rosario Sanchez Alfonso Lugo Pedro Ramirez Ricardo Ortiz Arturo Calderon 《Water, air, and soil pollution》1987,34(3):245-262
A protozoological survey was performed on a waste-stabilization pond to isolate, identify, and determine the incidence of ciliates present in these waters. The correlation between the species found and the physicochemical parameters was investigated. One hundred and eighty samples were analyzed from February 1983 to February 1984. Free-living ciliates isolated include:Carchesium polypinum Linnaeus,Vorticella microstoma Ehrenberg,Vorticella convallaria Linnaeus,Didinium balbiani Fabré-Domergue,Amphileptus claparedei Stein,Spathidium spathula Müller,Litonotus fasciola Ehrenberg,Paramecium caudatum Müller,Paramecium aurelia Ehrenberg,Tetrahymena vorax Kidder,Tetrahymena pyriformis Ehrenberg,Cyclidium glaucoma Müller,Aspidisca costata Ehrenberg, andStylonychia putrina Stokes. The performance of the pond was predominantly anaerobic. The temperature, total alkalinity, and nitrate concentration were the most variable parameters in the system studied. 相似文献
97.
98.
Abrahamsen B Zhao J Asante CO Cendan CM Marsh S Martinez-Barbera JP Nassar MA Dickenson AH Wood JN 《Science (New York, N.Y.)》2008,321(5889):702-705
Peripheral pain pathways are activated by a range of stimuli. We used diphtheria toxin to kill all mouse postmitotic sensory neurons expressing the sodium channel Nav1.8. Mice showed normal motor activity and low-threshold mechanical and acute noxious heat responses but did not respond to noxious mechanical pressure or cold. They also showed a loss of enhanced pain responses and spontaneous pain behavior upon treatment with inflammatory insults. In contrast, nerve injury led to heightened pain sensitivity to thermal and mechanical stimuli indistinguishable from that seen with normal littermates. Pain behavior correlates well with central input from sensory neurons measured electrophysiologically in vivo. These data demonstrate that Na(v)1.8-expressing neurons are essential for mechanical, cold, and inflammatory pain but not for neuropathic pain or heat sensing. 相似文献
99.
Sanchez PA 《Science (New York, N.Y.)》2002,295(5562):2019-2020
100.