不同沙地生境下黄柳(Salix gordejevii)种群若干数量特征的比较研究

Quantitative characteristics of Salix gordejevii population in different sandy land habitats

对分布于3种不同沙地生境(半固定沙丘、固定沙丘、丘间低地)黄柳灌丛的个体形态、生长和群体数量特征进行了比较研究,同时测定了灌丛下草本层植物种类组成及频度。结果显示:分布于丘间低地的黄柳灌丛当年枝平均长度增加缓慢,短枝条的比例较高,枝长频度分布(当年枝)峰值偏左,分枝也较多,叶片短而狭,长宽比大;与之相比,分布于半固定沙丘上的灌丛当年枝平均长度增加较快,长枝条比例较高,枝长频度分布趋于正态分布,分枝较少,叶片长而宽,长宽比小;固定沙丘上灌丛的上述特征大致介于二者之间,其枝长频度符合Weibull分布。3种生境条件下黄柳灌丛下草本层的种类组成频度也存在差异。

Plant morphology,growth and population characteristics of S.gordejevii in different sandy land habitats (semi fixed sand dunes,fixed sand dunes and inter dunes lowland),as well as species composition and their frequency in the herb layer of the scrubs,were compared.Plants in the inter dunes lowland were more branchy with a larger number of first year shoots which were shorter,and grew more slowly;the frequency distribution of the first year shoot lengths tended to have a 'thin' peak drifting towards the left;their leaves were shorter and narrower with a high length/width ratio.Plants growing in the semi fixed sand dunes,on the other hand,were less branchy with a larger number of first year shoots which were longer,and grew faster;the frequency distribution of the shoot lengths followed the Normal Distribution Model;their leaves were longer and wider with a low length/width ratio.The measures of the branching system and leaf dimensions of the plants in fixed sand dunes were rather intermediary between those of the above and the frequency distribution of the first year shoot lengths followed the Weibull Distribution Model. The species composition and their frequency in the herb layer of the scrubs also varied with habitats.