山东滨海盐碱地11个造林树种叶解剖特征对土壤条件的响应

叶片作为植物与大气环境连接的重要纽带, 对逆境具有强烈的响应。基于叶性状探讨植物对环境的适应机制对盐碱地植物群落构建具有指导意义。该研究以山东省滨海盐碱地3种不同土壤条件下的11个造林树种为对象, 通过对各树种叶解剖性状的测定分析, 阐明叶片功能性状与盐碱地土壤环境的关系, 以期为盐碱地植被修复与群落构建提供科学依据。主要研究结果: (1) 11个树种的叶片厚度较大, 栅栏组织发达, 紧密排列在叶肉近轴面, 呈3-5层。各树种叶片的栅栏组织与海绵组织厚度比值(PT/ST)普遍较高但差异较大, 可指示叶解剖特征在树种间的差异性。(2)不同树种的叶解剖结构在立地环境间具有显著差异, PT/ST可作为指示指标。(3)相关分析和冗余分析表明, 树种叶片解剖结构与立地土壤条件具有密切联系。PT/ST与土壤理化性质相关程度高, 且与土壤pH以及土壤电导率(25 ℃)均呈显著正相关关系, 与土壤硝态氮含量呈显著负相关关系。叶片特征和叶脉特征可解释叶性状随环境变异约84%的信息量。综上所述,叶解剖结构与盐碱地土壤条件存在密切关系, 基于叶解剖特征可进一步分析树种对盐碱环境的适应性, 并为盐碱地植物群落构建的树种选择提供科学依据。

Responses of foliar anatomical traits to soil conditions in 11 tree species on coastal saline-alkali sites of Shandong,China

Aims As an important link between plants and atmospheric environment, foliar organs have strong responses to stress. Understanding the adaptive mechanisms of plants to environments based on leaf traits is of great significance for establishment of plant communities in saline-alkali land. Methods Eleven tree species used for afforestation were studied under three soil conditions in the coastal saline-‌alkali land of Shandong Province. The foliar anatomical traits were measured, and the responses of these traits to saline-alkali soil environment were determined to reveal the relationships between foliar functional traits and soil conditions. Important findings (1) The leaves of the 11 tree species studied were thicker on the saline-alkali sites than on other sites, with 3-5 layers of well-developed palisade tissue closely arranged on the paraxial surface of the leaf mesophyll. The thickness ratio of palisade tissue to spongy tissue (PT/ST) was generally high but with large variations among the tree species. (2) The foliar anatomical traits differed among the three sites in different tree species. (3) Both correlation analysis and redundancy analysis (RDA) showed that the foliar anatomical traits were closely related to soil conditions; PT/ST was highly significantly correlated with soil indexes, positively with soil pH and soil conductivity at 25 ℃, and negatively with soil nitrate nitrogen content. Leaf characteristics and vein characteristics could explain 84% of the variations in leaf functional characteristics with environments. Overall, the foliar anatomical traits were closely related to soil conditions in saline-alkali land. The analysis of foliar anatomical traits could be used to study the adaptation of tree species to saline-alkali land, and as basis for tree species selection for vegetation restoration and community establishment.