[Objective] The aim was to study the effect of site factor on plant community characteristic in closed watershed in loess hilly and gully region.[Method] Based on the investigation of vegetation in the closed watershe...[Objective] The aim was to study the effect of site factor on plant community characteristic in closed watershed in loess hilly and gully region.[Method] Based on the investigation of vegetation in the closed watershed of Wuqi County in Shaanxi Province,the difference of plant community characteristic and species diversity under various site types was researched in our paper.[Result] In the investigation area,xerophytic herb was the main community,with sole species composition and simple community structure.Zonal vegetations were Artemisia sacrorum and Artemisia giraldii community;for plant diversity,the order of diversity index was ridge topgully bottomridge slopegully slope in various landform positions and semi-shady slopeshady slopesemi-sunny slopesunny slope in various slope aspects;with the increase of gradient,the diversity index of sunny slope changed with ＂S＂ type,and it reached maximum value at 37°.[Conclusion] Our study could provide theoretical foundation for vegetative restoration in loess hilly and gully region.展开更多
Using RAPD technique, the DNA diversity of Cephalotaxus mannii Hook. f., its genetic diversity pattern, the reasons for its endangered position and conservative approaches were studied. The results show that: 1. The...Using RAPD technique, the DNA diversity of Cephalotaxus mannii Hook. f., its genetic diversity pattern, the reasons for its endangered position and conservative approaches were studied. The results show that: 1. The genetic diversity of C. mannii collected from five localities in Hainan is low, and its adaptability to environmental change is weak. 2. The differences of genetic diversity between intra- and inter-populations are great, and the major variation distributes within the population (DNA diversity is 85.1%). 3. The excessive lumbering, man-made destruction, violent typhoon, edible value of the seeds and genetic drift were the main reasons for the low-level genetic diversity of C. mannii and its endangered position. 4. The difference of the micro-environment and other random factors affecting the population should also be taken into full consideration in the study and in protection of such occasionally scattered plants. 5. Enforced measures should be taken to protect the present population, enlarge the population and lower the loss rate of its gene. Mt. Limulin should be chosen as a conservative spot because of its high genetic diversity and less destruction of the forest. Meanwhile, the protection of other populations should be enforced. 6. The differences within and between the populations are great based on different primers used. The change of proportions in polymorphic loci between the populations is more than that between the primers.展开更多
Plant germplasm resources is the material foundation and key point for agricultural production, crop breeding and bioengineering. China is one of the centers for the origin of the cultivated plants worldwide, as well ...Plant germplasm resources is the material foundation and key point for agricultural production, crop breeding and bioengineering. China is one of the centers for the origin of the cultivated plants worldwide, as well as one of the countries with most abundant plant resources and the highest biodiversity. Strengthening research in the conservation and utilization of plant germplasm resources is of significant value and importance. In this study, the present status of conservation, utilization, and existing problems of plant germplasm resources in China and around the world were reviewed; further, through analyzing measures taken by global countries for plant germplasm resources protection, countermeasures for plant germplasm resources conservation in China were also presented from three aspects, namely, collection and conservation, information network construction and national legislation and policies.展开更多
基金Supported by Forestry Key Technology R&D Program in the 11th Five year Plan of China(2006BAD03A0302)~~
文摘[Objective] The aim was to study the effect of site factor on plant community characteristic in closed watershed in loess hilly and gully region.[Method] Based on the investigation of vegetation in the closed watershed of Wuqi County in Shaanxi Province,the difference of plant community characteristic and species diversity under various site types was researched in our paper.[Result] In the investigation area,xerophytic herb was the main community,with sole species composition and simple community structure.Zonal vegetations were Artemisia sacrorum and Artemisia giraldii community;for plant diversity,the order of diversity index was ridge topgully bottomridge slopegully slope in various landform positions and semi-shady slopeshady slopesemi-sunny slopesunny slope in various slope aspects;with the increase of gradient,the diversity index of sunny slope changed with ＂S＂ type,and it reached maximum value at 37°.[Conclusion] Our study could provide theoretical foundation for vegetative restoration in loess hilly and gully region.
文摘Using RAPD technique, the DNA diversity of Cephalotaxus mannii Hook. f., its genetic diversity pattern, the reasons for its endangered position and conservative approaches were studied. The results show that: 1. The genetic diversity of C. mannii collected from five localities in Hainan is low, and its adaptability to environmental change is weak. 2. The differences of genetic diversity between intra- and inter-populations are great, and the major variation distributes within the population (DNA diversity is 85.1%). 3. The excessive lumbering, man-made destruction, violent typhoon, edible value of the seeds and genetic drift were the main reasons for the low-level genetic diversity of C. mannii and its endangered position. 4. The difference of the micro-environment and other random factors affecting the population should also be taken into full consideration in the study and in protection of such occasionally scattered plants. 5. Enforced measures should be taken to protect the present population, enlarge the population and lower the loss rate of its gene. Mt. Limulin should be chosen as a conservative spot because of its high genetic diversity and less destruction of the forest. Meanwhile, the protection of other populations should be enforced. 6. The differences within and between the populations are great based on different primers used. The change of proportions in polymorphic loci between the populations is more than that between the primers.
基金Supported by the Beijing Nova Program(2008B37)the Major Research Program of Beijing Municipal Commission of Science and Technology(D131100000413001)+2 种基金National Key Technologies R&D Program(2012BAK26B03)the Special Fund for Construction of Scientific and Technological Innovation Ability of Beijing Academy of Agriculture and Forestry Sciencesthe Special Research Fund for the Youth of Beijing Academy of Agriculture and Forestry Sciences(QNJJ201211)~~
文摘Plant germplasm resources is the material foundation and key point for agricultural production, crop breeding and bioengineering. China is one of the centers for the origin of the cultivated plants worldwide, as well as one of the countries with most abundant plant resources and the highest biodiversity. Strengthening research in the conservation and utilization of plant germplasm resources is of significant value and importance. In this study, the present status of conservation, utilization, and existing problems of plant germplasm resources in China and around the world were reviewed; further, through analyzing measures taken by global countries for plant germplasm resources protection, countermeasures for plant germplasm resources conservation in China were also presented from three aspects, namely, collection and conservation, information network construction and national legislation and policies.
