高州油茶光合生理特性

Photosynthetic characteristics of Camellia gauchowensis

【目的】阐明高州油茶光合生理特征,为优良种质资源选择及高效栽培管理提供理论基础和技术指导.【方法】利用LI-6400便携式光合仪,测定高州油茶主要光合生理指标.【结果和结论】高州油茶净光合速率的日变化均呈"双峰型"曲线,其光饱和点为1 417μmol·m^(-2)·s^(-1),光补偿点为18.92μmol·m^(-2)·s^(-1),最大净光合速率为12.58μmol·m^(-2)·s^(-1).蒸腾速率各季度变化均呈"单峰型"曲线,最高值为3.65 mmol·m^(-2)·s~(^(-1)).胞间CO_2浓度日变化趋势为"U"型曲线.水分利用效率日变化均呈"降-升-降"的趋势.气孔导度日变化曲线有"单峰型"和"双峰型"2种,其中7、9、11月和次年1月为"双峰型",次年3月为"单峰型".光合有效辐射、空气温度、大气CO_2浓度,蒸腾速率和气孔导度与光合速率的相关性最大.

【Objective】The purpose of this study was to explain photosynthetic characteristics of the leaves of Camellia gauchowensis,providing a theoretical basis and technical guidance for the selection of fine resources,as well as effective management and cultivation of C. gauchowensis. 【Method】Photosynthetic characteristics of the leaves of C. gauchowensis were determined by a LI-6400 portable photosynthesis analysis system.【Result and conclusion】Diurnal variations in net photosynthetic rate( Pn) of the mature trees of C. gauchowensis presented a double-peak curve. The light saturation point was 1 417μmol·m^(-2)·s^(-1),with the light compensation point being 18. 92 μmol·m^(-2)·s^(-1),Pnmaxbeing 12. 58μmol ·m^(-2)·s^(-1). The diurnal variation in transpiration rate( Tr) of the mature trees of C. gauchowensis was characterized by a single-peak curve. The maximum of Tr of the mature trees was 3. 65 mmol·m^(-2)·s^(-1).The diurnal variations in intercellular CO_2 concentration( Ci) of C. gauchowensis presented a'U'curve in each month. The diurnal variations in water use efficiency( WUE) of mature trees presented a 'downup-down'curve all the year round. The diurnal variations in stomatal conductance( Gs) of mature trees presented a double-peak curve or a single-peak curve. In July,September,November and January,the diurnal variations in Gsof mature trees were both double-peak curves,and in March it was single-peakcurves. Photosynthetically-active radiation,air temperature,atmospheric CO_2 concentration,Tr and Gs were the main factors which influence the Pn of C. gauchowensis.