共查询到20条相似文献,搜索用时 125 毫秒
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香蕉是重要的热带亚热带水果,本文综合相关文献资料,从香蕉的起源与分布和现代生物技术在香蕉种质资源的研究与应用等剖析香蕉种质资源研究和应用的现状。对香蕉起源与分布的认识是香蕉种质资源研究的基础,目前多数学者都承认香蕉起源东南亚,对演化路线却存在许多争议,现代分子生物技术为解决这一问题提供了机会;分子标记技术成为香蕉遗传多样性研究的重要工具,可以很方便地进行香蕉分类、亲缘关系及演化做较为精确的研究,甚至辅助育种的应用;组织培养、细胞悬浮体系和原生质体培养技术的不断成熟,促进香蕉种质创新的发展,使香蕉突变育种和转基因育种成为可能。 相似文献
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中国有着丰富的野生花卉资源,文中综述了野生花卉的资源现状、保护和利用情况,简述了花卉资源研究的新技术和新方法,并就野生花卉资源发展前景提出了建议。 相似文献
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牟定县油茶产业发展现状与对策分析 总被引:2,自引:0,他引:2
介绍云南省牟定县适宜发展油茶产业的气候、土壤、土地资源、种苗供应等自然条件,发展木本油料产业的经验、投资环境优越等社会条件,以及油茶在牟定县的发展历史及现状.分析了油茶产业发展中存在的技术含量低,扶持力度不够,政策保障措施不够细化等问题,藉此提出了科学经营、实行行业标准化栽培管理、扶持龙头企业、建立油茶专业合作组织等对策. 相似文献
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分析了寻甸县退耕还林的成效,找出了退耕还林工程实施中存在的诸如林种结构不合理、树种选择不科学、容器苗使用偏低、抚育管理措施不力等问题。找出问题产生的原因,并针对上述问题提出应对的措施和建议。 相似文献
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Peter Sturmheit 《Agroforestry Systems》1990,10(3):265-289
An agroforestry and soil conservation needs assessment survey conducted in southern Zambia revealed valuable insight into needs, constraints and development options as perceived by smallholders themselves. Inadequate efforts to conserve soil are due to technical and socio-economic factors, they do not result from a lack of awareness of the widespread erosion threat. Fruit tree planting, windbreak establishment as well as the protection of the natural Faidherbia albida regeneration in cropland are popular agroforestry interventions whose positive effects are widely acknowledged. Forty-two perennial species were found to directly contribute to people's diet. Although local fuelwood and fodder shortages as well as the need for fencing are recognized only few respondents envisage agroforestry solutions such as fuelwood and fodder tree planting or live fencing. Most smallholders are interested in tree planting but have so far only planted few trees. Those planted are usually exotic fruit trees. Drought hardly, termite and browse resistant perennials adapted to smallholder tree planting must be provided by the extension services. The widespread exclusion of women from decision making and the lack of tenure security hampers female participation in agroforestry development and consequently threatens sustainable development altogether. 相似文献
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《Journal of Sustainable Forestry》2013,32(1-2):385-399
Summary Increasingly, urban and rural communities across the U.S. are looking at ecological systems as capital assets with values that are diminishing as they are degraded. Investments are needed so they can continue to provide ecological services critical to the environmental, social, and economic well-being of the communities. This paper explores “reinvestment” as term encouraging the development of mechanisms for sustained and long-term investment in “natural capital,” as well as the other forms of capital on which communities and society depend. It raises important questions on which there are information gaps, such as the value of ecological services, the level of investment needed to restore and maintain ecological systems, the activities to which investment dollars should be allocated, and where public and private investment dollars might come from. These questions are discussed at national, regional, and local scales, focusing on water-an ecological resource with immense value that connects ecosystems and communities at many scales. The paper presents lessons and reinvestment mechanisms from studies in California's Sierra Nevada ecosystem and community-based efforts in its northernmost drainage, the Feather River watershed. 相似文献
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祁连山浅山区沙棘人工林调节水分作用研究 总被引:1,自引:0,他引:1
通过对试验区沙棘林林冠层、枯枝落叶层、林地土壤层的生态水文功能分析,研究了祁连山浅山区沙棘人工林在调节水分方面的作用,结果表明:10年生沙棘林在郁闭度为0.7~0.8时,林冠对降雨的截留率为39.3%;枯枝落叶层厚度平均在1~3cm,枯落物质量22t·hm-2,水容重为干质量的2.12~4.25倍;蓄水量达13.65~23.37t·hm-2;林地0~20cm土壤的初渗率为16.165mm·min-1,是对照区的8.7倍;稳渗率为2.4mm·min-1,是对照区的2.53倍。 相似文献
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竹材表皮细胞的观察(一) 总被引:3,自引:0,他引:3
本文对国产17属33种竹材中部表皮细胞进行了初步的比较观察。发现有许多在外部形态上十分相似,难以区分的竹种,而在竹材表皮细胞微形态特征上有很大的不同,不论是属与属之间或种与种之间在微观特征上都存在着不同的差异,属与属之间如:Pseudosasa 与 Pleioblastus;Clavinodum 与 Pleioblastus;Sasa、Sasa-morpha 与 Indocalamus;Schizostachum 与 Bambusa、Dendrocalamus。种与种之间如:Sasa nubigena、Sasamorpha Sinica 与 Indocalamus(Nakai);Phyllostachys angustta 与 Ph.virdi-glancens;Schizost-achyum fungh(?)mii 与 S.pseudolima 等。文中对上述属与属之间和种与种之间在表皮细胞微观结构上的差异都作了比较详细的描述。有些竹种的表皮细胞特征在文中没有描述,但在表格及图片中也能看到它们的不同。利用这一特点,可以把在营养体和宏观形态上相近似或不易区别的竹种,很方便的加以分开。这将对研究竹种分类和鉴定竹种工作有一定的参考价值。 相似文献
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主要对刨切机与旋切机、刨切单板与旋切单板进行比较,并指出提高刨切单板和旋切单板质量的方法,介绍了国内大型木工机械刨切机和旋切机的主要产品及其型号和技术参数. 相似文献