摘要
为了揭示青藏高原高寒草原优势物种青藏苔草(Carex moorcroftii)和紫花针茅(Stipa purpurea)对高原特殊环境的适应性,该文研究了它们的叶片结构在自然环境梯度下的变化以及这些变化与生态因子之间的关系。结果表明:这两个物种叶片的大多数结构特征在各个样地间变化显著,其结构特征与环境因子间存在显著的相关关系。紫花针茅叶肉细胞大小随土壤有效K含量的增高而减小,下表皮细胞厚度和韧皮部面积随生长季云盖度的增高而增加,单一导管半径和导管平均面积随生长季月均湿度的增加而增大;青藏苔草上表皮细胞厚度随生长季月均最低温的降低而增厚,泡状细胞厚度(径向直径)随大陆度的增强而增加,上表皮细胞大小随土壤pH值的增大而增大,导管总数和韧皮部面积随土壤速效P含量的增高而增加。青藏苔草的保护组织、光合组织以及综合指标变异系数明显大于紫花针茅,仅维管组织指标变异系数小于紫花针茅。
Aims A comprehensive survey on anatomical features of the leaves of Carex moorcrofiii and Stipa purpurea, two dominant species in Tibetan Plateau, has been conducted. Quantitative analysis on the relation between ecological factors and leaf structure variation was carried out in order to find out how they are acclimated to environments and whether these two species with different reproductive behavior have different adaptation mechanisms.
Methods A transect was set along the Qinghai-Tibet Road from Xidatan to Yangbajing, with great change in ecological features： altitude from 4 586 to 4 901 m, growing season precipitation from 384 to 202 mm, growing season monthly average temperature from 5.1 to 1.4℃, growing season monthly average humidity from 65 % to 54%, growing season evaporation from 1 242 to 798 mm, and growing season monthly average wind speed from 2.4 to 4.0 m·s^-1. We collected leaf samples along the transect, embedded them in paraffin, stained embedded sections by astra blue-basic fuchsin, and measured them. Variation coefficient, multi-comparison, correlation analysis and regression analysis were used to analyze structural diversity and the relation between diversity and ecological factors.
Important findings The leaf of S. purpurea curls inward, with lower epidermis outside, and stomata and epidermal hairs appear only on the upper epidermis inside. The leaf of C. moorcrofiii usually unfolds like ＂V＂ in cross section with well-developed aerenchyma, and stomata and epidermal hairs appear only on the lower epidermis. The leaf structure of both species differs remarkably among populations. Multiple linear step by step regressions revealed for S. purpurea that there are significant linkages between soil available K and the size of mesophyll cells, growing season monthly average cloud coverage and lower epidermis thickness, growing season monthly average cloud coverage and phloem area, growing season monthly average humidity and single vessel semi-diameter, and growing season monthly average humidity and average vessel transverse section area. For C. moorcroftii, there are significant linkage between growing season monthly average lowest temperature and upper epidermis thickness, continentality and thickness of bullfform cells, soil pH value and size of upper epidermis cells, soil available phosphorus and vessel numbers, soil available phosphorus and phloem area, and soil available K and leaf aerenchyma area. Comparison of variance coefficients showed that C. moorcrofiii had greater integrative variability than S. purpurea.
出处
《植物生态学报》
CAS
CSCD
北大核心
2008年第2期370-378,共9页
Chinese Journal of Plant Ecology
基金
国家自然科学基金(30330130)
关键词
高寒草原
青藏高原
青藏苔草
紫花针茅
叶片结构特征
Alpine grassland, Tibetan Plateau, Carex moorcrofiii, Stipa purpurea, leaf structure
