桂北地区中华猕猴桃光合作用的日变化特征

为探明桂北地区猕猴桃的光合生理适应机制,以中华猕猴桃"桂海四号"(Actinidia chinensis cv.Guihaia 4)为对象,测定了其夏季和秋季的光合速率、蒸腾速率、气孔导度等生理指标,以阐明其光合特性的日变化特征。结果表明,猕猴桃6月和9月其光合速率日变化曲线均为双峰型,并具有不同程度的光合"午休"现象;均在上午10:00达到峰值,此时气孔限制值达到最大值,水分饱和亏缺和水分利用效率均较高,但下午出现峰值的时间不同。猕猴桃6月份的光合"午休"现象主要是由非气孔因素引起的,而9月份的光合"午休"现象主要是由气孔因素引起。6月份猕猴桃光合速率主要受光合有效辐射影响,9月份猕猴桃光合速率除受光合有效辐射影响外,还受大气饱和蒸汽压亏缺、气温和相对湿度气温的影响。猕猴桃光合特性日变化特征表明,为适应外界环境条件的变化,其光合特性发生了相应的调整,反映了对该地区特殊的气候环境的一种适应机制。

The Diurnal Changes in Leaf Gas Exchange of Actinidia chinensis cv. Guihaia 4

In order to clarify the physiology adaptive mechanism of the Kiwifruit(Actinidia chinensis cv.Guihaia 4),the diurnal changes in leaf gas exchange were measured.The results showed that the photosynthesis rate of June and September showed bimodal behavior and both had the photo-inhibition,but to the different extend.The maximum values of Pn were at 10:00 and with the maximum Ls,relatively high leaf-to-air vapor pressure deficit and water use efficiency.In the afternoon,the maximum values of Pn were at 14:00 and 16:00 respectively.The cause for the photo-inhibition of Kiwifruit in June and September was non-stomatal factors and stomatal factors,respectively.The Pn of June was mainly because of PAR,while in September it was mainly influence by leaf-to-air vapor pressure,air temperature and relative humidity.The diurnal changes in leaf gas exchange of Kiwifruit(Actinidia chinensis cv.Guihaia 4) indicated that the photosynthetic behavior changed corresponding in the environmental change,consequently reflected an adaptive mechanism.