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1.
岷江百合生境及遗传多样性   总被引:1,自引:0,他引:1  
在踏查岷江百合分布区的基础上随机选取两个阴坡与阳坡群体,设样地调查其群落特征,测定其土壤化学性质指标,并用ISSR分子标记分析两群体遗传多样性。结果表明,岷江百合生长在兰花莸、小角柱花、美丽胡枝子、黄花蒿等为优势的干旱河谷灌丛中,在垂直结构上居于灌木层片。数量上较多,但因冠副较小,群落外貌上不明显。土壤为褐土,呈弱碱性,土壤潜在肥力水平较高,但有效成分较低。阴坡土壤有效成分高于阳坡。物种水平的多态性谱带的比例为96.72%,有效等位基因数为1.5572,Shannon’s多样性指数为0.4932,平均期望杂合度为0.3276。其中阴坡群体的遗传多样性参数要高于阳坡群体。群体间遗传差异占总遗传差异的17.57%,群体内遗传差异占总遗传差异的82.43%。两个群体间的基因流为5.0660,说明两群体亲缘关系较近,而群体内遗传分化强烈,阴坡群体的遗传分化强于阳坡群体。  相似文献   
2.
泛在知识环境给高校图书馆建设与服务带来了一定的冲击,同时与带来了机遇,促使高校图书馆深入调研科研用户的需求,通过对科研用户信息行为的把握,更好地为用户服务。针对泛在知识环境下高校图书馆服务,笔者基于信息行为的研究,结合学科热点信息共享空间(IC),构建出虚拟知识共享空间,从理论方面介绍泛在知识环境、信息共享空间,从实践可能性分析信息行为研究主导下的虚拟知识共享空间服务对高校图书馆的价值。  相似文献   
3.

讨论了儿童医疗保健工作的特殊性和复杂性,提出了将现代信息技术与儿童医疗保健工作相结合,建立医疗机构、社区和家庭间的儿童医疗保健信息联网系统的构想。

  相似文献   
4.
采用Weibull分布模型、对数正态分布模型、对数级数模型、分割线段模型、几何级数分布模型来拟合珍稀植物南方红豆杉群落物种-多度分布格局,并用卡方临界值检验模型的拟合效果。结果表明:Weibull分布、对数正态分布、对数级数分布可用于描述南方红豆杉群落乔木层种-多度分布格局;而Weibull分布和对数正态分布适合于灌木层种-多度关系的描述。  相似文献   
5.
The United Nations effort to define Sustainable Development Goals (SDG's), emphasizing local goals and capacity building, offers a unique opportunity for soil science to demonstrate the role it can play when focusing on these goals. Several strategic reports have presented key issues for sustainable development: food security, freshwater and energy availability, climate change and biodiversity loss are issues most frequently being listed, not soil degradation. Focusing on soil contributions towards interdisciplinary studies of these key issues, rather than emphasizing soils by themselves, is therefore bound to be more effective for the soil science profession. But this is still inadequate when studying land‐related SDG's, requiring a broader ecosystem approach that can be achieved by a direct link between soil functions and corresponding ecosystem services. Thus, the key issues are not considered separately but linked as part of a dynamic ecosystem characterization following a narrative as is demonstrated for food security, that can be well addressed by precision agriculture. As all key issues and at least five of the ten SDG's are directly land‐related, soil science can potentially play an important role in the suggested interdisciplinary studies. But in addition, the current information society with knowledgeable stakeholders requires innovative and interactive transdisciplinary scientific approaches by not only focusing on knowledge generation but also on co‐learning with stakeholders and, important, on implementation. The soil science discipline can become more effective in the transdisciplinary context by: (1) reconnecting the knowledge chain, linking tacit with scientific knowledge both ways, (2) simplifying soil terminology, (3) learning to deal with “wicked” environmental problems for which no single solutions exist but only a series of alternative options for action, balancing economic, social and environmental considerations, (4) educating “knowledge brokers”, linking science with society in land‐related issues, acting within a “Community of Scientific Practice”, and (5) modernizing soil science curricula. Transdisciplinary approaches are crucial to achieve SDG's, linking science and society. There is a need for specific results on the ground illustrating with hard data the key role soils can play in realizing SDG's.  相似文献   
6.
Community structure of soil arthropods associated to Pittocaulon (Senecio) praecox was investigated in two sites with different vegetal cover in El Pedregal de San Ángel Ecological Reserve, South of Mexico City during thirteen-month period. The relationship of composition and abundance with soil variables was studied. A total of 101 483 specimens belonging to 28 taxa and 191 morphospecies were collected in both sites (Open site: Abundance: 60,369, 27 taxa and 181 morphospecies; Closed site: 41 114, 26 taxa and 179 morphospecies), the value of Shannon's diversity index was marginally higher in Closed site (H = 3.67) than in Open site (H = 3.59), according to a modified t-test for comparing indexes (t91418 = 9.6946; p < 0.001). Most abundant groups in both sites were Cryptostigmata and Prostigmata, with variations during the study period. The highest amount of specimens was recovered during the rainy season (May–October). The most abundant guilds recorded in both sites were predators, fungivores, detritivores and herbivores. The composition and trophic guilds of edaphic arthropods in the sites were affected by the microhabitat characteristics due to soil characteristics. According to a two-way ANOVA test, a significant effect due to site (F1,286 = 17.85, p < 0.001) and month (F12,286 = 22.68, p < 0.001) on the density of edaphic arthropods was recorded, but no significant differences in abundance were found when the interaction between both variables (F12,286 = 0.77, p > 0.05) was considered. The RDA shows that the soil variables explain 23.5% of the variation observed in the distribution of species, and that variation is related mainly to the presence of K, P, Na and Mg, and groups of predator arthropods are more related to the aforementioned variables, while detritivorous groups are more related to MO, N contents, relative humidity and pH. The microenvironmental characteristics recorded in both sites can explain differences in composition and abundance of soil arthropods.  相似文献   
7.
论述了洪雅丘陵疏林草丛草地与农隙草丛草地两种草地类型中6个群落的植物性生产能力及相关的多项生态经济性状、种群优势度(SDR)、重要值(Ⅳ);比较了两种草地类型各群落间SDR、Ⅳ及植物产量、经济类群组成、各项指标的差异性、共同性。说明自然因素(特别是气候)及人为因素(放牧、刈割、烧草)对草地植被组成及产量的影响。  相似文献   
8.
信阳市南湾水库库区森林植被南湾水库库区的水资源涵养和水土保持具有重要的作用。本文对水库加区的森林植被的环境,资源状况,类型进行了调查分析,并提出了保护管理的建议。  相似文献   
9.
我国农业农村发展变化迅速,对各类从业人员的能力与素质提出了新的要求,因此要把握新形势下农业继续教育重点,主动适应这种新的变化,大力加强农业继续教育,为农业增产、农民增收、农村社会和谐稳定提供人才保障。  相似文献   
10.
栽培环境pH值对冬小麦根系pH值的影响   总被引:2,自引:1,他引:1  
对生长在不同 pH环境条件下几个冬小麦品种苗期根系 pH值的测定表明 :在酸性、中性、微碱性环境条件下生长的冬小麦苗期根系均表现为偏酸性 ;不同品种在相同 pH环境中根系 pH值存在差异 ;同一品种在不同 pH环境中根系 pH值也存在差异。各品种根系 pH值随环境 pH值变化的大小 ,能反映该品种的适应性及自我调节能力。  相似文献   
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