短花针茅叶片解剖结构及与气候因子的关系

Anatomical structure of Stipa breviflora leaves and its relationship with environmental factors

短花针茅是荒漠草原的主要建群物种,在放牧利用和维持生态系统稳定方面有重要的作用,短花针茅叶片结构的抗旱性可为草原物种的抗逆性研究提供参考依据。本研究采用短花针茅叶片石蜡切片对叶片实际结构进行矢量化,统计各结构面积、厚度、密度等参数,选择角质层厚度/叶片厚度、维管束/叶片面积、栅栏组织厚度/叶片厚度、主脉维管束导管腔/主维管束面积、表皮细胞密度和表皮毛密度等6个指标进行统计得到叶片结构数据,随后分别对8个样地的叶片结构数据和气候数据进行CCA分析,对叶片结构与主导气候因子进行Pearson相关性分析。实验结果表明,1)为了适应高温、干旱的生长环境,短花针茅叶片具有典型的旱生结构;2)影响8个样地短花针茅叶片结构差异的主导气候因子为热量因子,水分因子居于次要地位;3)短花针茅叶片维管束和叶面积的比值与年均气温和年均降水量都存在显著相关性,主维管束导管腔与维管束面积的比值与年平均气温存在显著相关性;4)短花针茅叶片结构相似性矩阵和遗传相似性矩阵之间不存在一致性。

Stipa breviflora is the constructive species in desert steppe and plays an important role in grazing use and stabilizing desert grassland ecosystems.The characteristic of S.beviflora leaf structure with drought resistance can provide a good reference for grassland species.S.beviflora leaves from eight sites were paraffin wax sectioned and double-stained,then observed with an OLYMPUS CX41 microscope,and imaged by a CANON DS16275 digital camera.The area,thickness and density of corneum,vascular bundle,vascular catheter cavity of the main vein,palisade tissue,leaves,epidermal cells,and leaf trichomes were calculated with ArcGis.Six indicators（corneum thickness/leaf thickness,vascular area/leaf area,palisade tissue thickness/leaf thickness,the area of main vein vascular bundle catheter cavity/ mainvascular bundle,epidermal cell density and trichome density of leaf-like structures） from the eight sites were selected for CCA（canonical correspondence analysis） with climate data and the relationship between leaf structure and environmental factors was analyzed using Pearson analysis.Finally,the correlation between two similarity matrixes of leaf structure and genetics was calculated by a Mantel test.1） The leaf structure of S.reviflora showed typical drought resistance;2） Temperature was the dominant environmental factor for the differentiation structure of S.beviflora leaves,with moisture second;3） There were significant correlations between the ratios of vascular area within leaf area,the main vascular bundle with the vascular bundle and annual mean temperature and the ratio of vascular area within leaf area and annual mean precipitation;4） There was no significant correlation between two similarity matrixes of leaf structure and genetics.