叶片水分输导能力限制热带蕨的光合作用(英文)
作者单位：Key Laboratory of Economic Plants and Biotechnology Kunming Institute of Botany Chinese Academy of Sciences Key Laboratory of Tropical Forest Ecology Xishuangbanna Tropical Botanical Garden Chinese Academy of Sciences
会议名称：《生态文明建设中的植物学：现在与未来——中国植物学会第十五届会员代表大会暨八十周年学术年会》
会议日期：2013年
学科分类：090706[农学-园林植物与观赏园艺] 0907[农学-林学] 09[农学]
基 金：supported by the National Natural Science Foundation of China (31170315, 30900174, 31270453) the West Light Foundation of the Chinese Academy of Sciences
关 键 词：Fern leaf traits nutrient photosynthesis water transport vein density
摘 要：Ferns are important components of the forest flora, having critical functions in ecosystem processes, especially in tropical rainforests. Their remarkable degree of diversity and abundance reflect their ecological success in both the past and present. However, ferns inherently have slower growth rates and lower photosynthetic potentials than angiosperms. Low photosynthetic rate of a species can be resulted from a series of biotic and abiotic factors, such as supply of water and nutrients. Up to date, the primary determinant of photosynthetic potential in fern is not fully understood. In the present study, we used a phylogenetically comparative method to investigate 24 leaf traits of 30 tropical ferns in a common garden. The objectives were to examine the correlated evolution among functional traits, and attempt to disentangle the relative effects of water transport capacity and nutrient concentration on photosynthesis of these tropical ferns. Compared with epiphytic ferns, terrestrial ferns had higher silicon concentration, vein density (D vein ), stomatal density (SD), stomatal conductance (g s ), and photosynthetic capacity (A max ), but lower values for epidermal thickness (LET) and leaf thickness (LT). Across species, both area-based A max and mass-based A max were positively correlated with D vein and g s , but not with leaf element concentrations, LT and LET. SD correlated positively with area-based A max , D vein and g s , with the correlation between SD and D vein remaining significant after phylogenetic correction. Leaf water content showed significant correlations with LT and LET. Our results provide evidence that low A max of the studied ferns is more constrained by water transport capacity than by nutrients. These findings add new insights into the evolutionary correlations among traits involving carbon and water economy in ferns.