黄土高原不同退耕年限坡地植物比叶面积与养分含量的关系

Relation between specific leaf areas and leaf nutritent contents of plants growing on slopelands with different farming-abandoned periods in the Loess Plateau

对黄土高原不同退耕年限坡地植物比叶面积(SLA)和养分含量进行研究,探明其随生境条件而发生的变异及其与土壤理化特性之间的关系。结果表明,立地和物种水平植物SLA存在显著差异,SLA变化范围各不相同,植物叶片C、N和P含量以及C/N、N/P和C/P在不同退耕年限坡地间不具有一致性的变化,这表明不同物种叶性因子随生境发生的变化较为复杂。草地植物叶片SLA和叶片C含量为负相关,与N、P含量呈极显著的正相关(P<0.01)。土壤理化特性对叶片SLA和养分含量的关系因物种而异,综合所有植物进行分析,土壤理化特性与植物SLA的相关性不明显,但与叶片养分含量关系密切。所以,生境条件的差异可能是植物叶片结构特性和养分组成发生变化的重要原因,但调控植物叶性特征的因素较为复杂,不同的植物具有各自相应的对生境条件的适应机制。

Leaf has the fundamental functions of capturing light energy and assimilating carbon in most plants, and the differences between the ways by which it acquires processes and invests resources can have very great effects on the species composition and functioning of an ecosystem. It has been widely agreed that leaf traits such as specific leaf area （SLA） and leaf nutrient contents are sensitive indicators of environmental conditions. The variation and the relation between SLA and leaf nutrient content of plant can represent the responses and adaptations of the plant to climatic and environmental conditions. The study was carried out to investigate the variation of the SLA and leaf nutrient content of plants growing on slopelands with different farming abandoned periods in the Loess Plateau with the purpose of finding out their variation to their sites and species the plants significant difference in SLA and the ranges of their SLA differently varied; their carbon,nitrogen and phosphorous contents, and C/N, N/P and C/P ratios varied consistently in slopelands with different farming abandoned periods, indicating that in different plant species the leaf-reated factors varied with environmental conditions in a complex manner. On the grassland plants, the SLA was negatively correlated with the leaf carbon contents and appeared extremely significantly positively correlated with the leaf N and leaf P （P 〈 0.01 ）. The realtions of the SLA and the leaf nutrients to soil physical and chemical properties varied depending the plant species and analysis considering all the plants indicated that the SLA did not appeared remarkably correlated with soil physical and chemical properties but closely related to the leaf nuritent content. Therefore, the habitat differences may be the important reasons for the variations in leaf sturcture and leaf nutrient concentration, and because the leaf trait-regulating factors were very complex, each species has its adaptaiton mechanism to the habitat conditions.