微地形与小生境尺度下喀斯特森林植物的化学计量特征及其适应机制

项目研究背景：茂兰喀斯特森林是一种长在石头上的森林，生态系统类型多样、物种组成丰富，形成了罕见的生物基因库，成为科学家持续关注的焦点。那么，在如此严酷生境下，其森林生态系统的稳定性以及生物多样性如何维持？为回答这个问题，本项目基于前期研究成果，从生态化学计量学的视角，对茂兰喀斯特微地形与小生境下森林植物的化学计量特征及其适应机制进行了研究，研究结果意义重大。.主要研究内容：1）喀斯特森林不同功能（类）群植物的养分含量和化学计量特征；2）微地形因子与小生境类型对喀斯特森林植物化学计量特征的影响；3）喀斯特森林植物对微地形与小生境等环境因子变化的生理生态调控机制。.重要结果：1）喀斯特森林不同功能（类）群植物化学计量特征的分布格局及其对养分吸收的趋同和分异性；2）喀斯特森林植物养分含量与化学计量特征的内在耦合关系，以及植物Ca、Mg含量对其限制性养分因子的调节作用；3）喀斯特森林植物化学计量比对该区域植物生长的指示意义；4）微地形因子与小生境类型对喀斯特森林植物化学计量特征的影响程度，以及植物对微地形与小生境等环境因子变化的生理生态调控机制；5）喀斯特森林植物在该区域严酷生境下的生存策略以及对复杂地形的适应机制。.关键数据：1）微地形与小生境下喀斯特森林不同功能（类）群植物C、N、P、K、Ca、Mg等养分含量以及各元素间的化学计量比；2）该区域主要优势植物的叶面积（LA）、叶厚度（LT）、比叶面积（SLA）、叶干物质含量（LDMC）、叶片含水量（LWC）和叶组织密度（LTD）等结构型性状，以及净光合速率（Pn）、蒸腾速率（Tr）、气孔导度（Gs）、胞间二氧化碳浓度（Ci）和水分利用效率（WUE）等功能型性状；3）该区域主要优势植物的养分重吸收率（RE）。.科学意义：通过本项目的研究，旨在为喀斯特森林生态系统稳定性及其生物多样性维持机制提供理论依据，为其保护和管理提供科学参考。

Research background of this project indicate that Maolan karst forest is a forest on rocks with a rich diversity of species and a lot of different ecosystems. As a rare biological gene pool, the karst forest has been a focus of attention of many scientists. How to maintain the ecosystem and species diversity under such harsh conditions? To answer the question on basis of preliminary studies, the project will study the forest plant growing on micro-topography and micro-habitat from the perspective of stoichiometry and the expected outcome might be significant. .The research contents are as follows: 1) Studying the nutrient content and stoichiometry characteristics of different functional group plants in Maolan karst forest; 2) Analyzing the influence of micro-topography and micro-habitat factor on stoichiometry characteristics of karst forest plants; and 3) Exploring the physiological regulation mechanism of plant to the change of micro-topography and micro-habitat factor. .Important results include: 1) The distribution pattern of stoichiometry characteristics of different functional group karst forest plant and showing the convergence or divergence in nutrient absorption; 2) The coupled linkage between plant nutrient content and their stoichiometry characteristics, especially the regulating effect of Ca and Mg content of leaves on limiting nutrient factors; 3) The indicative role of plant stoichiometry ratio on forest plant growth in karst regions; 4) The impacts of micro-topography and micro-habitat on plant stoichiometry ratio and the physiological regulation mechanism of plant to the change of micro-topography and micro-habitat; and 5) The survival strategy and adaption mechanism of the karst forest plants in the harsh and complicated terrain of the region. .Critical data would be composed of: 1) Different karst forest plant nutrient content such as C, N, P, K, Ca, Mg. and the stoichiometry ratio between them; 2) The leaf area (LA), leaf thickness (LT), specific leaf area (SLA), leaf dry matter content (LDMC), leaf water content (LWC) and leaf tissue density (LTD) as well as the net photosynthetic rate (Pn), transpiration rate (Tr), stomatal conductance (Gs), intercellular carbon dioxide concentration (Ci) and water use efficiency (WUE); and 3) Nutrient reabsorption rate of dominant plant in the study area. .Scientific significance is that the results of this project can be expected to present a theoretic reference for maintaining the stability of forest ecosystem and its biodiversity and provide a scientific reference for protection and management of the karst forest ecosystem.