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喀斯特季节性雨林优势树种叶片微形态与光合生理特征及其生态适应性

摘要:为研究喀斯特季节性雨林优势树种对异质性生境条件的适应策略,以广西弄岗原生性 森林7 个优势树种为对象,测定各树种成年个体叶片微形态指标及生长季光合生理特征,探 讨树种叶片结构功能对喀斯特峰丛山地异质性生境的响应规律。结果表明:(1)沿喀斯特 地貌部位的洼地-中坡-山顶生境梯度,树木的叶片紧密度、栅栏组织厚度、角质层厚度、上 表皮厚度等9 个微形态指标呈现显著上升趋势,叶片疏松度呈现显著下降趋势;(2)沿洼 地-中坡-山顶生境梯度,树木的光补偿点、暗呼吸效率、最大蒸腾速率等呈现显著上升趋势; 而最大水分利用效率、最大胞间CO2 浓度、表观量子效率等呈现显著下降趋势;(3)叶片 紧密度与光合能力、蒸腾能力等相关指标表现为显著正相关;叶片疏松度与这两类指标表现 为显著负相关。综上所述,喀斯特季节性雨林优势树种叶片功能性状存在光合效率和耐旱性 之间的权衡,洼地生长的树木具有显著的弱光适应特征,中坡生长的树木表现较广的生境适 应范围,山顶分布的树种受强光、高温和裸岩限制,表现出较强的干旱适应特征以及保守的 生态适应策略。

英文摘要:In order to study the adaptive strategy 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 indexes of adult individuals of each tree species and the photosynthetic indexes of leaves in the growing season of these trees were measured. The ecological adaptability of these leaf structural and functional indexes to the habitat gradient in the karst peak cluster depression landform was tested. The results were as follows: (1) Along the karst habitat gradient from depression to peak, nine leaf micro-morphological indexes, such as leaf compactness, palisade tissue thickness, cuticle thickness, and upper epidermis thickness, showed a significant upward trend, while leaf looseness showed a significant downward trend. (2) Along the karst habitat gradient from depression to peak, the light compensation point, dark respiration efficiency, and maximum transpiration rate 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. The above results show that 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 depressions have obvious adaptive characteristics to weak light. Trees distributed on the middle slopes show extensive habitat adaptability. Due to the limitation of strong light, high temperature and exposed rock, the trees distributed on the mountain peaks show strong drought adaptability and conservative ecological adaptive strategies.

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[V1] 2022-06-29 20:52:10 chinaXiv:202206.00190V1 下载全文
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