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植物不同等级的叶脉承担着不同的功能,叶脉密度与叶大小的异速生长模式有助于揭示植物表型可塑性形成机制。利用Arc GIS建立研究区域的数字高程模型(DEM),采用标准化主轴估计(standardized major axis estimation,SMA)方法,研究了兰州市北山不同坡向人工林刺槐(Robinia pseudoacacia)一级和二级叶脉密度与叶大小的关系。结果表明:随坡向由北坡向东坡、南坡和西坡转变,植被群落的郁闭度、高度和土壤含水量呈现先减小后增大趋势,刺槐的单叶面积、比叶面积和叶片偏心率(eccentricity)呈先减小后增大趋势,刺槐叶片的一级和二级叶脉密度呈先增大后减小趋势;4个坡向刺槐一级叶脉密度与叶面积呈显著的负相关关系(P<0.05),二级叶脉密度与叶面积呈极显著负相关关系(P<0.01),斜率均显著大于-1。刺槐叶大小与不同等级叶脉密度权衡关系的坡向差异,是植物对异质性生境适应的结果。
Different levels of plant leaf veins bear different functions, and allometric growth patterns of leaf vein density and leaf size can help reveal the mechanism of plant phenotypic plasticity. The digital elevation model (DEM) of the study area was established by using ArcGIS, and the standardized major axis estimation (SMA) method was used to study the density of Robinia pseudoacacia primary and secondary leaf veins Relationship with leaf size. The results showed that with the change of slope from north slope to east slope, south slope and west slope, the canopy density, height and soil water content of vegetation community firstly decreased and then increased. The single leaf area, specific leaf area And leaf eccentricity decreased firstly and then increased. The leaf densities of primary and secondary leaves of Robinia pseudoacacia first increased and then decreased. The leaf densities of the primary leaf of the four slopes were significantly different from those of the leaf area (P <0.05). There was a significant negative correlation between the leaf density and leaf area (P <0.01), and the slope was significantly greater than -1. The difference in slope between the Robinia pseudoacacia leaf size and the leaf density density at different levels is the result of adaptation of plants to heterogeneous habitats.