红砂的净光合速率与蒸腾速率的日变化特征

Diurnal changes of net photosynthetic rate and transpiration rate of Reaumuria soongorica

以野生红砂（Reaumuria soongorica）为研究对象,在2004年5～7月早7：00～晚20：00（晴天）测定其净光合速率（Pn）、蒸腾速率（E）、光合有效辐射（PAR）、大气温度（T）等指标，结果表明：红砂的净光合速率日变化曲线呈M型,有明显的“光合午休”现象;红砂的蒸腾速率日变化曲线也呈M型,但“午休”现象不明显;有效光合辐射对红砂的净光合速率影响较大,大气温度则对红砂的蒸腾速率影响较大。

From May to July in 2004,wild Reaumuria soongoricawas taken as the studied object,its net photosynthetic rate（P.）, transpiration rate（E）, photosynthetically active radiation（PAR） and atmospheric temperature（T） were determined from 7：00 am to 20：00 pm （sunny day）. The results showed that diurnal change curve of net photosynthetic rate of Reaumuria soongorica was M-type, and obvious＂noon break＂phenomenon was presented,diurnal change curve of transpiration rate was also M-type,but ＂noon break＂phenomenon was not obvious, photosynthetically active radiation has great effect on net photosynthetic while atmospheric temperature has strong effect on transpiration rate.