Guangxi Zhiwu (Mar 2023)
Leaf micromorphological, photosynthetic physiological characteristics and their ecological adaptability of dominant tree species in a karst seasonal rain forest in Guangxi, China
Abstract
In order to study the adaptive strategies of dominant tree species in a karst seasonal rain forest to heterogeneous habitat conditions, seven dominant tree species in a virgin forest in Nonggang, China, were taken as the research objects. The leaf micromorphological physiological characteristics of adult individuals of each tree species and the photosynthetic indexes of leaves in the growing season of these trees were measured, and the response of leaf structure and function of tree species to heterogeneous habitat in karst peak-cluster mountain was discussed. The results were as follows: (1) Along the karst habitat gradient from valley to hilltop, nine leaf micromorphological indexes, such as leaf compactness, palisade tissue thickness, cuticle thickness, and epicuticle thickness, showed a significant upward trend, while leaf looseness showed a significant downward trend. (2) Along the karst habitat gradient from valley to hilltop, the light compensation points, dark respiration rate, and maximum transpiration rates of these leaves all showed a significant upward trend. However, the maximum water use efficiency, the maximum intercellular CO2 concentration, and the apparent quantum efficiency showed a significant downward trend. (3) Leaf compactness was positively correlated with photosynthetic and transpiration ability indexes. Leaf looseness was negatively correlated with these two types of indexes. In conclusion, there is a trade-off relationship between photosynthetic efficiency and drought tolerance in leaf functional traits of dominant tree species in the karst seasonal rain forest. Trees distributed in the valley have obvious adaptive characteristics to weak light. Trees distributed on the slope show extensive habitat adaptability. Due to the limitation of strong light, high temperature and exposed rock, the trees distributed on the hilltop show strong drought adaptability and conservative ecological adaptive strategies.
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