岷江上游干旱河谷矮探春叶片特征与环境因子的关系

对岷江上游干旱河谷矮探春(Jasminumhumile L.)的叶片形态解剖特征进行了显微观察,分析了海拔梯度上叶片形态与环境因子的关系。结果表明,矮探春叶片呈长椭圆形,叶肉组织分化明显;随着海拔升高,叶面积、厚度、干重、饱和含水量、海绵组织厚度,中脉厚度以及厚角组织厚度/中脉厚度之比(M/C)等呈增大趋势,而栅栏组织厚度/海绵组织厚度之比(P/S)则减小;叶片长/宽比、表皮厚度、栅栏组织厚度和比叶重在海拔梯度上无明显差异。叶面积、干重、饱和含水量、叶厚度和海绵组织厚度等参数两两之间呈显著正相关,而它们与P/S均呈显著负相关。叶面积、干重、海绵组织厚度和M/C等主要受土壤含水量的影响,并随着土壤含水量增加而增大;P/S随着土壤含水量和年降水量增加而减小;叶片厚度、饱和含水量和中脉厚度均随着温和度的降低而增大。岷江上游干旱河谷区土壤水份和生长季温度可能是影响矮探春叶片形态解剖特征的主要因子。

Leaf Traits in Jasminum humile Related to Environmental Factors in the Dry Valley of the Upper Minjiang River

The relationship between leaf characteristics and environmental factors was determined in Jasminum humile L. grown in the dry valley of the upper Minjiang River. The leaves were elliptic and leaf mesophyll tissue was distinctively differentiated. Leaf area, leaf thickness, leaf dry weight, leaf saturated water content, spongy tissue thickness, mid-vein thickness and the ratio of mid-vein thickness to collenchyma thickness (the M:C ratio) increased with increasing altitude. The ratio of palisade tissue thickness to spongy tissue thickness (the P:S ratio) declined as altitude increased. No significant differences were found in the ratio of leaf length to leaf width, epidermal thickness, palisade tissue thickness and specific leaf weight along altitude gradient. There were significant and positive correlations among leaf area, leaf dry weight, saturated water content, leaf thickness and spongy tissue thickness, while all of these parameters were negatively correlated with the P:S ratio. Leaf area, leaf dry weight, spongy tissue thickness and the M:C ratio increased mainly with increasing soil water content. However, the P:S ratio decreased with increasing soil water content and annual rainfall. Leaf thickness, leaf saturated water content and mid-vein thickness increased with decreasing temperateness. It is likely that leaf traits in J. humile are affected mainly by soil water content and temperature during the growing period in the habitat.