红树植物无瓣海桑光合作用日变化及其影响因子研究

文章以广州南沙区红树林湿地公园的无瓣海桑人工林为研究对象，测定叶片净光合速率（Pn）、蒸腾速率（Tr）的日变化并探讨其与相关生理生态因子的关系。结果表明，无瓣海桑叶片的Pn日变化呈双峰曲线，峰值出现在上午10：00时和午后14：00时，并出现明显午休现象。影响Pn的主要生理生态因子有光强、气孔导度、相对湿度和胞间CO2浓度等；无瓣海桑叶片的Tr日变化呈明显的单峰曲线，峰值出现在中午12：00时，影响Tr的生理生态因子主要有叶面温度、气孔导度和相对湿度等。无瓣海桑光补偿点和光饱和点分别为100，1800μmol·m^-2s^-1左右，CO2补偿浓度和饱和浓度分别为50，900μmol·mol^-1左右。

Research on Daily Course of Photosynthesis of Mangrove Plant Sonneratia apetala and Its Influencing Factors

The daily courses of net photosynthetic rate （Pn） and transpiration rate （Tr） in leaves of Sonneratia apetala from mangrove forest wetland park of Nansha District in Guangzhou together with influencing factors were studied under natural condition. The results showed that the curve of daily courses of its Pn had two peaks appearing at 10：00 and 14：00 respectively; There was a clear depression at noon. The main physio-ecological factors affecting Pn were temperature, conductance, relative humidity, intercellular carbon dioxide density and so on ; Daily Tr was obviously one-peak curve and its peak value appeared at 12：00 ,the main physio-ecological factors affecting Tr were temperature of leaf, conductance, relative humidity and so on . The light compensation point and light saturation point of Sonneratia apetala were about 100 and 1 800 μmol · ma s^-1 ; And the CO2 compensation point and CO2 saturation point were about 50 and 900 μmol · mol^-1.