【摘 要】
:
There are five wild populations of Cycas fairylakea in Guangdong Province,China,three of which are newly found.A study of the biological characteristics of C.fa
【机 构】
:
South China Botanical Garden,the Chinese Academy of Sciences,Guangzhou 510650,China“,”Horticulture D
论文部分内容阅读
There are five wild populations of Cycas fairylakea in Guangdong Province,China,three of which are newly found.A study of the biological characteristics of C.fairylakea populations showed that this species had a narrow colonization area within 300 hm2,and an island patte of distribution.Because of the overexploitation,urbanization,environment pollution,plant diseases,and insect pests,the wild populations and individuals of C.fairylakea decreased markedly in the past decades.All five populations have an opposite pyramid age structure,few coning plants,few seed production,and low level of seed germination rate or sterility.In conclusion,C.fairylakea in Guangdong Province was threatened seriously and an urgent need to take effective efforts to protect the plants and habitats in its location sites was required.
其他文献
We analyzed the activities of specific enzymes,esterase and peroxidase,and the electrophoresis profiling of isozymes of both the second-generation (MI) and the
Recent collections from six sections in Lanongla area,Tethyan Himalaya allow the establishment of four buchia assembles.In ascending they are Buchia-Buchia spit
The Janzen-Connell (J-C) hypothesis provides a mechanism explaining the high species diversity in tropical rainforests. It postulates that predation could cause
Invariant manifolds are complicate random sets useful for describing and understanding the qualitative behavior of nonlinear dynamical systems.The purpose of th
广告界中有句名言:″我知道我的广告费至少浪费了一半以上,但我不知道究竟浪费在哪里?“这句话说的是由于广告投放不当而造成巨大浪费的问题。广告投放如何将钱用在″刀刃”
根据2003年连云港海州湾渔业生态修复水域的本底调查资料,应用Ecopath with Ecosim(Ew E)软件中的Ecopath模块,本研究构建了该区域的生态系统能量流动简易模型,初步评估了该
“比较广播学”作为一门学科能不能成立,有待研究和论证,这里不作断言。但在国际广播研究中采取比较方法早已是客观存在的事实,并且取得了一些积极成果,只是没有自觉地、有
We investigated the possible existence of superoxide dismutase (SOD; EC 1.15.1.1) isoenzymes in the pollen of Nicotiana tabacum (Petit Havana SR-1 cultivar). To
根据2010年环渤海主要河流及海上油气平台的石油烃入海量,利用建立的与水动力模块相耦合的污染物输移-扩散模型,数值模拟了2010年渤海表层石油烃浓度分布以及主要入海河流、
夏玉米是黄淮海地区最主要的夏季粮食作物,通过光谱技术进行作物长势及氮素营养状况的实时监测,可以为黄淮海地区夏玉米种植区玉米生长无损监测和精确农作管理提供理论基础和关键技术。本研究以黄淮海地区麦茬夏玉米为研究对象,综合运用作物冠层反射光谱探测技术和夏玉米生理指标测试技术,分析了不同氮肥水平下夏玉米冠层光谱反射特征及其与夏玉米叶面积指数、生物量、叶片氮素状况、叶片糖氮比和叶片色素含量的相关关系,筛选出