人工针叶林林下11种植物叶片解剖特征对不同生境的适应性

Adaptation of leaf anatomical characteristics of eleven understory species to different environments in coniferous plantations

人工林内两种主要生境(林窗和林内)的光照条件存在着显著差异,而这种差异也是影响人工林林下植物叶片形态和结构的重要环境因子。对川西米亚罗林区60a人工云杉林2种不同生境(林窗和林内)的11种植物比叶重、叶片解剖结构及气孔特征等进行了比较研究,结果显示:林窗生境中11种供试植物比叶重(LMA)均显著大于林内生境;多数阔叶物种叶片厚度(LT)、栅栏组织厚度(PT)、栅栏组织厚度/海绵组织厚度(PT/ST)、栅栏细胞层数在林窗生境中更大或更多,但叶表皮细胞厚度(UET、LET)、海绵组织厚度(ST)在两种生境中无显著差异;林窗生境中生长的各物种栅栏细胞均为长形且长度大于林内生长的相同物种;不同物种气孔密度(SD)对两种生境有一致的响应趋势,但显著程度有异,除三褶脉紫菀外10种植物的气孔长径(SL)受两种生境影响不大,这与气孔特性受多种环境因素制约,且各种因素对气孔作用效应和作用方面不同有关。结合各物种喜光特性综合分析后认为同一群落的林下植物对光生境具有一定程度的趋同适应性;从可塑性方面分析发现叶片光合组织的可塑性大于非光合组织,且各物种叶片平均可塑性与喜光特性基本吻合。

The differences in light conditions between forest gaps and underneath close canopy in plantation forests, can be an important factor affecting leaf morphological and anatomical characteristics of understory species. In this paper, the leaf anatomical, stomatic and m （forest gaps and underneath orphological characteristics of eleven understory species grown in two different environments close canopy） were studied and compared in a 60a of spruce plantation in Miyaluo located in western Sichuan, China. The results showed that eleven species in forest gaps had significantly higher dry weight per leaf area than those under close canopy, and most broad-leaved plants in gaps increased leaf thickness, palisade parenchyma thickness, the palisade parenchyma cell layers and the ratio of palisade to spongy parenchyma （PT/ST）. No significant difference in thickness of leaf epidermal cell and spongy parenchyma of most species were observed between two environments. The palisade parenchyma cells of the broad-leaved species in gaps were significantly longer than those grown under the canopy. All studied species appeared a similar trend of reduction in the stomatal density under close canopy, with various degrees of statistical significance. The stomatal length of all species except Aster ageratoides Turcz were not evidently changed by the contrasted environments in our study, mainly because leaf stomatal characteristics were related with many factors in natural environment. Our results suggested that species in same community had convergent evolution on adaptation to light condition. The average leaf plasticity indexes were accordant with their light-requirement approximately, and the photosynthetic parenchyma was greater than non-photosynthetic parenchyma in same leaves.