灵武长枣光合作用研究初报

选择灵武长枣7a生幼龄植株和12a生成年植株为研究对象,采用CARIS-1型便携光合测定系统,测定不同月份灵武长枣幼龄、成年植株光合作用,研究灵武长枣光合作用的季节变化规律。结果表明:在整个生长季节内,灵武长枣的光合作用呈现出明显的月份变化规律,且幼龄株、成年株的光合作用特性不一;成年植株的净光合速率(Pn)呈单峰型曲线变化,最高值出现在夏季8月份(12μmol.m-2.s-1),而幼龄植株的净光合速率呈双峰型曲线变化,最高值分别出现在6和8月份(分别为7.8和13.9μmol.m-2.s-1);气孔导度、蒸腾速率随月份的变化规律与净光合速率的变化规律相同,但幼株的气孔导度、蒸腾速率明显大于成年植株。成株和幼株水分利用效率的月份变化趋势相似,5月最大,6月份下降到最低值,后略有上升。幼株、成株的胞间二氧化碳浓度值在5～9月维持在150～250μmol/mol。因此,灵武长枣的光合作用高峰期在6、8月,幼株的光合能力强于成株。

Primary Study on Photosynthesis of Zizyphus jujuba Mill.cv.Lingwuchangzao

Selected seven-year-old individuals(young individual) and twelve-year-old individuals(mature individual) in Lingwuchangzao as materials,used automatic photosynthesis test instrument(CARIS-1),the photosynthesis of young individual and mature individual at different months during whole growing season were determined,the seasonal variation of photosynthesis in Zizyphus jujuba Mill.cv.Lingwuchangzao were studied.The results showed that the photosynthesis in the jujube showed significant month variations,and the photosynthesis characteristics of young individual and mature individual were different.The variation trend of net photosynthesis rate of the mature individual during growing season was a unimodal curve in which the peak of Pn occurred at Aug.that was 12 μmol·m-2·s-1,but the variation trend of Pn of the young individual during growing season was a bimodal curve in which the peaks of Pn occurred at June and Aug.that was 7.8 μmol·m-2·s-1 and 13.9 μmol·m-2·s-1 respectively.The variation trends of stomatal conductance(Gs) and transpiration rate(Tr) were same as the variation of Pn during different months,but the value of Gs and Tr of young individuals were greater than that of mature individuals.There was no big different of the variation trends of water utilization efficiency(WUE) between young and mature individuals,and the peak value of WUE occurred at May while minimum value occurred at June,and then the value of WUE increased slowly,but reduced before leaf falling.The intercellular CO2 concentration(Ci)value of young and mature individuals during May and Sept.was from 150～250 μmol/mol,but the Ci increased before the leaf falling.It could be concluded that the photosynthesis peak of Lingwuchangzao was occurred at June and Aug.And the photosynthetic capacity of young individuals in Lingwuchangzao was stronger than that of mature jujube.