东江中上游3种造林树种的光合-光响应特征

 以东江中上游6年生的山乌桕、枫香和南酸枣为材料,采用LI-COR公司L i-6400光合作用测定系统测定光合、蒸腾、水分利用效率等生理参数及其光响应过程,探讨3树种在自然生境条件下的光合-光响应特征。结果表明:3树种光合-光响应曲线均符合非直角双曲线模型(R2>0.98)和指数模型(R2>0.98);3树种表观量子效率和暗呼吸速率均表现为山乌桕>南酸枣>枫香,山乌桕在弱光下光合能力要高于枫香和南酸枣,但对光合产物消耗大;山乌桕最大净光合速率与枫香、南酸枣间差异显著(0.05);3树种介于阴生植物和阳生植物之间,山乌桕对强光的适应能力较好,对光照强度表现出一定的适应性和可塑性,具有较宽的光照生态幅,对弱光与强光的利用能力较高;3树种净光合速率光响应均值表现为山乌桕>南酸枣>枫香,耗水能力表现为山乌桕>南酸枣>枫香,而水分利用效率表现为枫香>山乌桕>南酸枣。

Photosynthesis and photo-response characteristic of 3 plantation tree species in the upper and middle reaches of Dongjiang River

By using Li-6400 portable photosynthesis system produced by LI-COR company,six-year old Sapium discolor,Liquidambar formosana and Choerospondias axillaries,in the upper and middle reaches of Dongjiang River were selected as experimental materials for comparative studies on photosynthetic and physiological parameter characteristics,such as photosynthesis,transpiration,and water use efficiency,etc,and photosynthesis and photo-response characteristic of the three plantation tree species in natural habitats.The results showed that the photosynthesis-light response curves of the three species could be well simulated by the non-rectangular hyperbola model（R20.98） and exponential curves（R20.98）.Apparent quantum efficiency and dark respiration rate in a descending order of Sapium discolor,Choerospondias axillaries,Liquidambar formosana,the photosynthetic ability of Sapium discolor was higher than that of Choerospondias axillaries,Liquidambar formosana,while Sapium discolor showed high photosynthate consumption.There were significant differences in maximum net photosynthetic rate between Sapium discolor and Choerospondias axillaries,Liquidambar formosana（P0.05）.The three species were between shade plants and sun plants,specifically,Sapium discolor has high adaptability to high light,and shows great adaptable and plastic to different light intensity,and wider light ecological amplitude,and has higher ability to use low light and high light.The net photosynthetic rate of Sapium discolor was highest,followed by Choerospondias axillaris,Liquidambar formosana,the transpiration rate in a descending order of Sapium discolor,Choerospondias axillaris,Liquidambar formosana,and water use efficiency in a descending order of Liquidambar formosana,Sapium discolor,Choerospondias axillaris.