作 者 ：邓蕾,王鸿喆*,上官周平,刘广全
期 刊 ：生态学报 2010年 30卷 18期 页码：4889~4897
关键词：柠条锦鸡儿；比叶面积；营养元素；生境；水蚀风蚀交错区；黄土高原；
Keywords:Chinese Caragana, specific leaf area, nutrient, habitat, wind-water erosion, the Loess Plateau,
摘 要 ：通过对黄土高原水蚀风蚀交错区主要生长月份柠条锦鸡儿（Caragana korshinlii Kom.）叶片比叶面积（SLA）和矿质元素含量的测定，探讨其对生境条件及生长时间的响应规律，结果表明：不同生境柠条锦鸡儿叶片SLA随生长月份的变化趋势基本一致，但变化差异不显著；不同生境叶片有机碳（C）含量变化差异不显著；叶片全氮（N）含量、全钾（K）含量对生长月份的变化响应明显，变异幅度较大，而随生境条件发生的变异较小；叶片全磷（P）含量在不同生境随着生长月份发生的变异较大\.不同生境叶片N/P随月份发生的变异较大、C/P的变异较小；叶片C/N、C/K在不同生境间无明显差异，但均随生长月份而产生较大变化，叶片N、P、K的含量与SLA相关性不明显。所以，生境条件和生长时间是柠条锦鸡儿叶片结构特性和养分组成发生变化的重要原因，其叶片比叶面积与矿质养分含量受外界环境因子和自身发育状况的共同调控。
Abstract:Most plants have fundamental capacities of capturing light energy and assimilating carbon, and their differences in resource acquisition, processing and investment have very great effects on the species composition and function of an ecosystem. It is widely accepted that leaf traits such as specific leaf area (SLA) and leaf nutrient contents are sensitive indicators of environmental conditions. The variation in SLA and leaf nutrient content and the relation between the two can reflect plant responses and adaptations to climatic and environmental conditions. The study was done to investigate the SLA and mineral nutrient contents of Chinese Caragana (Caragana korshinlii Kom.) in the Loess Plateau region suffering both wind and water erosions in its main growing months in order to find out the patterns whereby the SLA and mineral nutrient contents of Chinese Caragana vary with different habitats and growing months. The results show that of Chinese Caragana, the SLA little differed among different habitats (P> 0.05). In different habitats, the SLA of Chinese Caragana varied identically and corresponded with its leaf growths. In this study, the SLA of Caraganas varied much so that Caraganas adapted itself to different habitats. On the north-facing slopes, the SLA were highest but the leaf N contents and light intensities were the lowest, and on the south-facing and half-south facing slopes the SLA were the lowest, but the leaf N content and light intensities were the highest. This was probably caused by different soil moisture of the different slopes. The leaf organic carbon contents ranged from 43.171% to 45512%, 42217% to 44.326%, 43.620% to 44.517% on the south-facing, half-south facing and north-facing slopes, respectively. The Leaf nitrogen (N) and potassium (K) totals differed among the different habitats, but differed significantly among the months. The Leaf phosphorus (P) contents differed significantly among the habitats and the growing months. In the different habitats, as the growing months alternated, the leaf N/P ratios varied significantly, but the C/P ratios varied little; and the C/N and C/K ratios did not significantly differed but all varies significantly as the growing months alternated. However, the mean N/P ratios in all habitats were higher than 16, indicating that in the area suffering both water and wind erosions the growth of Chinese Caragana was more susceptible to P constraint, which was mainly attributed to the lower soil P content that probably resulted from strong soil and water erosions occurring in the area. As the growing months alternated, the leaf N, P and K contents, the leaf C/N and C/P ratios varied significantly in the different habitats, and this was probably mainly due to the different nutrient requirements of the plant at the different growth stages, such as allocating more N to insoluble proteins to enhance cell wall resilience, and increasing leaf cell density to tolerate environmental stress. The higher the leaf organic carbon contents and N/P rations of Chinese Caragana were, the lower the leaf areas per unit mass, and as growing months alternated, the correlation between the leaf SLA and leaf C, N, P and K contents and the leaf C/N, C/P, C/K, N/P ratios varied little, but the roles of the correlation perform differently. Therefore, the leaf SLA of Caragana were the result jointly resulting from the actions of all the leaf nutrients in the different growing months. Consequently, the habitats and growing times were probably the important reasons for the variations in structural characteristics and nutrient composition, but the factors regulating leaf characteristics were more complex, Chinese Caragana had its own adaptation mechanisms to its habitats and growing months in respect to different nutrient elements.
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