青藏高原和内蒙古高原草地植物的气孔特征及其与环境的关系

Stomata, as an essential connection between the internal air spaces of plants and the external atmosphere, regulate plants water loss and carbon gain, and thus exert large controls on ecosystem water and carbon cycles. The relationship between stomata occurrence/stomatal traits and environment factors is important for understanding plant adaptive mechanisms and strategies. Numerous studies have reported patterns of stomatal structure and how stomatal traits, such as stomatal size, aperture, density and index respond to the environments. However, in large scale, the relationship between stomatal features and environmental factors are not well-documented, and the stomatal features and their correlation with environmental factors in regions of extreme environment such as physiological drought and great diurnal temperature variation, remain unclear and infrequently reported. Therefore, the present study aims to explore the leaf stomatal features of grassland plants and their relationship with environmetal factors in large scale and in regions of extreme environment. On the basis of extensive collection and comprehensive analysis, and by using the techniques of plant anatomy, plant physiology and stoichiometry, we investigated the leaf stomatal features and leaf functional traits of the grassland plants on the Tibetan and Inner Mongolian Plateau; and accessed the relationships between the stomatal features and the leaf functional traits and environmental factors; and discussed the response of stomata to environment in plants belong to different stomatal apparatus types, different life forms and taxonomies. By comparison of the stomata of plants in different regions and their relationships with environmental factors, we try to demonstrate the changing trend of stomata in different habitats. This study will contribute to a further understanding of leaf anatomic characteristics of China's grassland plants and their spatial variability, and provide the theory basis for the protection and improvements of China's grasslands.

气孔是植物与环境进行水气交换的主要通道，在影响全球水和碳循环方面起重要作用。目前不同地域植物气孔特征与环境关系的大尺度比较研究相对较少，对极端环境中植物气孔特征是否具有特殊性尚不清楚，同时也不清楚气孔特征的空间变异受哪些环境因素调控。本项目拟对我国青藏高原和内蒙古高原主要草地类型中优势或常见植物进行大量取样，运用植物形态解剖学、植物生理学和生态化学计量学等方法，研究我国草地植物叶片的气孔特征及叶功能属性；利用一般线性模型等统计学手段，分析叶气孔特征与叶功能属性以及环境因子的关系，探讨不同气孔器类型、不同功能型和不同分类群植物的气孔对环境因子响应的异同；通过对青藏高原与内蒙古高原草地植物叶气孔特征及气孔-环境关系的对比分析，试图揭示植物气孔在适应不同环境时的变化规律。本项目的实施将有助于深入地认识我国草地植物的叶形态解剖特征及其空间变异, 同时也为我国草地的保护和改良提供参考信息。

通过对我国主要草地类型优势或常见植物大量野外取样和室内实验分析，利用统计学的方法，研究了青藏高原与内蒙古高原草地植物气孔特征的分布规律及其与环境因子的关系。结果表明：青藏高原和内蒙古高原草地植物的叶表面特征均形成了一些适应环境的结构特点；两地草地植物的气孔大小差异不大，但内蒙地区植物的气孔密度明显高于青藏地区，在内蒙古地区，降水相关因子与气孔指标关系显著，而在青藏地区，气孔特征与温度相关因子关系密切，温度和降水分别是两地植物气孔特征的主导因子；肾形保卫细胞形成的气孔和哑铃型保卫细胞形成的气孔在对环境因子的响应上未发现显著不同，不同功能型植物和不同植物类群之间气孔特征-环境关系存在差异，同科同属植物的气孔特征与环境间的关系较为类似。单生型气孔和双生型气孔对环境的响应未见显著差异。青藏高原单子叶植物叶片的各解剖指标值均小于内蒙古高原草地植物对应的指标；而青藏高原双子叶植物叶片除了叶肉细胞密度外，其余五个指标的平均值都高于内蒙。该结果可为预测未来气候条件下我国草地植物的变化提供科学依据, 也为我国草地的保护和改良提供参考信息。