几个柑桔品种叶片光合特性比较研究

为了研究不同柑橘品种的光合特性差异,用Li-6400型便携式光合测定仪和分光光度计对4个柑橘品种(奈92-1脐橙、沙糖橘、沙田柚和贡柑)叶片的光合参数和叶绿素含量进行测定。结果表明:(1)奈92-1脐橙、贡柑叶片的净光合速率(Pn)日变化表现为"单峰"型曲线,早上10:00时左右出现峰值,而沙糖橘、沙田柚则为典型的"双峰"型曲线,早上8:00时出现首峰,而次峰分别在12:00时和14:00时出现;日Pn最高值以沙田柚最高,高低顺序为沙田柚>贡柑>奈92-1脐橙>沙糖橘,除沙糖橘无光合"午休"外,其余品种均有明显的"午休"现象。(2)奈92-1脐橙有较高的水分利用率(WUE),而沙田柚和沙糖橘则较低。(3)叶绿素含量与其Pn呈正相关趋势,花青苷则相反,表现为负相关关系,而类胡萝卜素与Pn之间相关性不明显。综合Pn和WUE可知,沙田柚、贡柑的光合性能较高;而沙田柚和沙糖橘的WUE较低,干旱季节要注意淋水保湿。

Comparing of Photosynthetic Characteristics among several Citrus Cultivars

In order to investigate the differences of photosynthetic characteristics among four citrus cultivars,photosynthetic parameters and chlorophyll content of leaf of ''Nai 92-1'',''Shatianyou'',''Shatangju'' and ''Gonggan'' were measured by the Li-6400 portable photosynthesis system and spectro photometer(UV-2000)during summer.The results indicated that:(1)the diurnal change of net photosynthetic rate(Pn)of both ''Nai 92-1'' and ''Gonggan'' exhibited only one peak in the curves at 10:00,while that of ''Shatangju'' and ''Shatianyou'' exhibited a typical bimodal curve with the first peak at 8:00,and the second peak occurred at 12:00 and 14:00 respectively.The cultivar of ''Shatianyou'' had the highest daily Pn value(''Shatianyou''>''Gonggan''>''Nai92-1''>''Shatangju'').All cultivars showed midday depression of photosynthesis except for ''Shatangju''.(2)Water use efficiency(WUE)of ''Nai92-1'' was higher than that of other cultivars,while that of ''Shatianyou'' and ''Shatangju'' were relatively low.(3)There was positive correlation between Pn and the chlorophyll content of leaf,while the anthocyanin was negatively correlated to Pn.And there was no significant relation between Pn and the carotenoid.It was concluded that according to Pn and WUE,''Shatianyou'' and ''Gonggan'' were equipped with better photosynthetic function.While irrigation of ''Shatianyou'' and ''Shatangju'' should be carefully applied due to their low WUE in order to keep moisture especially during the drought period.