摘要:选取桂林喀斯特石山生境中常见的50种植物为研究对象，分别测定叶片单位面积最大净光合速率（A_area）、单位质量最大净光合速率（A_mass）、气孔导度（Gs）、水分利用效率（WUE）、胞间/环境CO₂浓度比值（Ci/Ca）和蒸腾速率（Tr）等光合特性指标，探讨不同物种光合特性的差异以及光合特性之间的内在联系，以此探究不同植物适应喀斯特石山生境所表现出的光合生理特性。结果表明，50种植物叶片A_area，A_mass，Gs，WUE，Ci/Ca和Tr的平均值分别为8.35 μmol m^-2 s^-1，110.98 nmol g^-1 s^-1，0.10 mol m^-2 s^-1，94.84 μmol/mol，0.57和2.37 mmol m^-2 s^-1；方差分析表明，不同物种之间在A_area，A_mass，Gs，WUE，Ci/Ca和Tr之间存在显著差异。Pearson相关性分析表明，表征50种常见植物叶片光合特性的6个指标相关性除Ci/Ca与A_area和A_mass，WUE与A_mass不一致外，其他指标两两之间相关性均表现为一致性，其中Gs与Ci/Ca呈极显著的正相关。主成分分析表明，在6个光合特性指标中，Gs和Ci/Ca可作为反映喀斯特石山植物适应生境的重要光合指标，主要表征对水分条件的敏感程度以及耐旱性强弱，同时反映了植物叶片光合速率大小，用于衡量植物对喀斯特生境的生理生态适应性。基于Gs和Ci/Ca进行聚类分析表明，50种植物划分为3类：即中等Gs较高Ci/Ca型，较低Gs较高Ci/Ca型和较低Gs，Ci/Ca型。本研究表明，喀斯特生境植物在生理生态方面所表现出的适应策略主要为对资源利用方式及抵御外界不利环境的适应策略，这为后续选择物种加速植被恢复演替进程提供了参考。



Abstract:The photosynthetic characteristics of leaves were selected as the research objects, and the following indicators were determined respectively: the greatest photosynthetic rate per unit area (A_area), the most photosynthetic rate per unit mass (A_mass), the stomatal conductance (Gs), the water utilization efficiency (WUE), the concentration ratio of intercellular/environmental CO₂ (Ci/Ca), and the transpiration rate (Tr) of 50 common plant species growing on karst hills of Guilin, China. We aim to explore the photosynthetic characteristics' differences among species and their intrinsic relationships and to discuss the photosynthetic physiological characteristics of different plants adapting to karst rocky mountain habitat. The results showed that the average values of A_area, A_mass, Gs, WUE, Ci/Ca and Tr of 50 plant leaves were 8.35 μmol m^-2 s^-1, 110.98 nmol g^-1 s^-1, 0.10 mol m^-2 s^-1, 94.84 μmol/mol, 0.57, and 2.37 mmol m^-2 s^-1, respectively. Analysis of variance showed that there were significant differences between A_area, A_mass, Gs, WUE, Ci/Ca and Tr among different species. Pearson correlation analysis showed that the correlations of the six indicators that characterized the photosynthetic characteristics of 50 common plant leaves were consistent except for the relationships of Ci/Ca, A_area and A_mass, WUE and A_mass were inconsistent, and the correlations between other indicators showed consistency, of which Gs and Ci/Ca were extremely obvious positive correlation. The principal component analysis showed that among the six photosynthetic characteristics indicators, Gs and Ci/Ca might be used as important photosynthetic indicators to reflect the adaptability of karst stone mountain plants in habitats. They mainly represented the physiological status of plants and their sensitivity to water condition and the drought resistance, and at the same time, they also reflected the photosynthetic rate of plant leaves, which might be utilized to measure the physiological and ecological adaptability of plants to karst habitats. The cluster analysis based on Gs and Ci/Ca showed that 50 plants were divided into three categories: namely, medium Gs with higher Ci/Ca type, lower Gs with higher Ci/Ca type, and lower Gs, Ci/Ca type. It can be seen from this study that the adaptation strategies of karst habitat plants in terms of physiology and ecology were mainly reflected on the one hand in the way of resource utilization and on the other hand to resist the adverse external environment, which provides a reference for the subsequent selection of species to accelerate the process of vegetation restoration and succession.





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