排序方式： 共有9条查询结果，搜索用时 218 毫秒
1
1.
Fatou Ndoye Aboubacry Kane Niokhor Bakhoum Arsène Sanon Dioumacor Fall Diégane Diouf Samba Ndao Sylla Amadou Mustapha Bâ Mame Ourèye Sy Kandioura Noba 《Agroforestry Systems》2013,87(4):941-952
The benefits of inoculation with six arbuscular mycorrhizal fungi (AMF) isolates (Glomus aggregatum, G. fasciculatum, G. intraradices, G. manihotis, G. mosseae, and G. verriculosum) were investigated on seedlings of Acacia senegal (L.) Willd., a multipurpose tree legume highly valued for arabic gum production. Mycorrhizal root colonization, plant growth and relative mycorrhizal dependency (RMD) were measured in A. senegal seedlings growing in soils from three geographical sites in Senegal (Dahra, Bambey and Goudiry) and two soil conditions (sterilized vs unsterilized) in the glasshouse. The impact of inoculation on mycorrhizal root colonization and plant growth depended on AMF isolates, soil origins and soil conditions. Mycorrhizal root colonization and plant growth were increased in sterilized soils regardless of soil origin and AMF isolates. The degree of RMD of A. senegal seedlings varied with soil origin, soil condition and AMF isolates. A. senegal showed the highest RMD values, reaching a maximum of 45 %, when inoculated with G. manihotis. However, in unsterilized soils, no significant effect of AMF inoculation on plant growth was observed despite significant root colonization with certain AMF isolates in Dahra and Goudiry soils. This indicates that the most infective AMF isolates were not the most effective and unsterilized soils may contain effective mycorrhizal propagules. In conclusion, it is important to consider the native mycorrhizal component of the soils before harnessing mycorrhizal inoculation programs for sustainable agroforestry systems. 相似文献
2.
In Senegal at Nioro experimental station the 15 N 2 isotope dilution technique was used at field conditions for estimating fixation of N 2 in Faidherbia albida, mono cultured and mixed with the reference species, Parkinsonia aculeata. Trenched and nontrenched plots within the plantation were labeled with 15 N 2 - ammonium sulphate containing 2 atom % 15 N excess at the equivalent amount of 20 kg N ha -1. The proportion of fixed N 2 was lower than that previously measured in experiments using Parkia biglobosa as a reference tree species: 20.3% vs. 54.7%. This difference might be due to physiological differences between the two reference species. Significant effect of trenching vs. nontrenching to the labeled area was observed on the percentage of N 2 derived from atmosphere (% Ndfa) of F. albida. The % Ndfa was higher in trenched than in nontrenched labeled area (+ 34.3%). There was no difference however in the amount of N 2 fixed in trenched and nontrenched plots although the estimate in the former (6.70 2 g N plant -1) was slightly higher than that in the later (5.60 g N plant -1). Thus trenching the labeled area seems to be necessary for estimating the N 2 fixed by F. albida in the field. 相似文献
3.
Divine Foundjem-Tita Zac Tchoundjeu Stijn Speelman Marijke D’Haese Ann Degrande Ebenezer Asaah Guido van Huylenbroeck Patrick van Damme Ousseynou Ndoye 《Small-Scale Forestry》2013,12(3):489-505
Agroforestry and planting trees on farmers’ fields have been reported as important elements in a strategy to meet the millennium development goals of poverty reduction and climate change improvement. However, their uptake seems to be constrained by factors both internal and external to the household and related to the policy and legislative environment. This paper examines the impact of these factors on farmers’ decisions to plant trees. Cameroon is used as a case to analyse whether existing policies and legislation governing trees support or discourage tree planting, using qualitative content analyses. Although their mission papers and statements suggest most national government policies in Cameroon address tree planting and agroforestry, actual legislation designed to follow up the policies mostly contradicts the poverty reduction goals. Often legislation and regulations are more conservation-oriented and do not provide a clear procedure to distinguish between products from trees found in the wild and those gathered from farmers’ fields. 相似文献
4.
In Chaberia ovina species an electrophoretic study of 15 loci of the following enzymes has been conducted: glucose phosphate isomerase, mannose phosphate isomerase, glucose-6-phosphate dehydrogenase, glutamate-oxaloacetate transaminase, superoxide dismutase, isocitrate dehydrogenase, hexokinase, adenylate kinase, malate dehydrogenase, malic enzyme, carbonic anhydrase and 6-phosphogluconate dehydrogenase. The genetic variability has been relatively high, with 40% polymorphism values noted, an 0.10 mean heterozygosity observed and an 0.17 mean heterozygosity expected. The greater part of the allele frequencies were not in Hardy-Weinberg equilibrium. 相似文献
5.
Long smut is a limiting factor in sorghum productivity in some countries and therefore, a threat to food security. Long smut (Sporisorium ehrenbergii Vánky) disease response was assessed in experiments on 51 sorghum accessions including 31 commercial hybrids and 20 cultivars from the United States of America (USA) in 2004 and 2005 at the Agronomic Research Stations in Bambey and Nioro, Senegal, West Africa. The highest disease incidence of 44.33% in 2004 and 16.47% in 2005 was observed in hybrid A425, and no infection was noted in hybrids 3552 and A571 in 2005 at both locations. Hybrids 730, 837, P84552, TR438, TR65G, and Wac660 exhibited low levels of infection. Among the cultivars and parental lines, SRN39 recorded the highest disease incidence of 48.0% followed by B.Tx623 with 45.8%, whereas B.9612 and R.9645 consistently recorded low levels of infection. These two cultivars B.9612 and R.9645 may possess genes for long smut resistance. All other promising sorghum cultivars and parental lines to be released/registered in the USA exhibited varied levels of susceptibility. In order to establish the sources of long smut resistance, it is of paramount importance to conduct additional screenings of aforesaid hybrids/lines in a wide spectrum of selections that would be carried out under varied environmental conditions. 相似文献
6.
7.
A. Faye T. Krasova-Wade J. Thioulouse Y. Prin I. Ndoye B. Dreyfus 《Soil biology & biochemistry》2009,41(6):1245-1252
Many fast growing tree species have been introduced to promote biodiversity rehabilitation on degraded tropical lands. Although it has been shown that plant productivity and stability are dependent on the composition and functionalities of soil microbial communities, more particularly on the abundance and diversity of soil symbiotic micro-organisms (mycorrhizal fungi and rhizobia), the impact of tree introduction on soil microbiota has been scarcely studied. This research has been carried in a field plantation of Acacia holosericea (Australian Acacia species) inoculated or not with an ectomycorrhizal fungus isolate, Pisolithus albus IR100. After 7 year's plantation, the diversity and the symbiotic properties of Bradyrhizobia isolated from the plantation soil or from the surrounding area (Faidherbia albida (Del.) a. Chev. parkland) and able to nodulate F. albida, a native Sahelian Acacia species, have been studied. Results clearly showed that A. holosericea modified the structure of Bradyrhizobia populations and their effectiveness on F. albida growth. This negative effect was counterbalanced by the introduction of an ectomycorrhizal fungus, P. albus, on A. holosericea root systems.In conclusion, this study shows that exotic plant species can drastically affect genotypic and symbiotic effectiveness of native Bradyrhizobia populations that could limit the natural regeneration of endemic plant species such as F. albida. This effect could be counterbalanced by controlled ectomycorrhization with P. albus. These results have to be considered when exotic tree species are used in afforestation programs that target preservation of native plants and soil ecosystem rehabilitation. 相似文献
8.
9.
Bassiaka Ouattara Khadidiatou Ndoye Ndir Mame Codou Gueye Ibrahima Diédhiou Adeline Barnaud Daniel Fonceka Ndiaga Cissé Elie Léonard Akpo Diégane Diouf 《Genetic Resources and Crop Evolution》2014,61(6):1039-1045
Significant efforts have been undertaken in West Africa to increase biofuel production with the expectation to alleviate the dependency on fossil energies and to reduce rural poverty by diversifying cultivated crops. In this context, Jatropha curcas L., a shrub belonging to Euphorbiaceae family, has gained great interest because of its oil which can be converted to biodiesel. It is also highly adaptable to marginal soils due to its drought-tolerant characteristics. Characterisation of J. curcas germplasm in Senegal could be an important input for its better management and in identifying genotypes that could be used in breeding program. Genetic diversity of 103 accessions including 82 accessions from different agro ecological zones in Senegal and 21 exotic accessions was assessed through 33 microsatellite markers. All the markers gave amplifications at the expected band size. Only one microsatellite marker, JCT17, was polymorphic showing 3 alleles and allows distinguishing 2 accessions from Burkina Faso. The surprisingly low level of genetic variation might be because introduction of J. curcas in Senegal seems to have been done from one or a few origins and the species has not regained genetic diversity since then due to vegetative propagation. Cultivation of J. curcas at large scale may face to vulnerability to pests and require many cautions. They are necessity to widen the genetic base of J. curcas in Senegal via new introductions from its centre of origin. 相似文献
1