几个柑桔品种叶片光合特性比较研究

以4个不同柑桔品种(奈92-1脐橙、沙糖桔、沙田柚和贡柑)为试材，对其田间条件下叶片光合特性进行比较研究。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，峰值均在早上10：00左右时出现，而沙糖桔、沙田柚则为典型的“双峰”型曲线，且首峰均在早上8：00左右时出现，次峰分别在12：00时和14：00左右时出现；4个柑桔品种的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>沙糖桔，除沙糖桔无光合“午休”外，其余品种均有明显的“午休”现象。2)叶绿素含量与Pn呈正相关趋势，花青苷则为负相关，而类胡萝卜素与Pn之间相关性不明显。

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.