库尔勒香梨3种树形光合特性的比较

Comparison of Photosynthetic Characteristics in Different Tree Shapes of Korla Fragrant Pear

利用CB-1102便携式光合蒸腾仪,对库尔勒香梨3种树形的光合生理特性进行了比较研究。结果表明,在晴天条件下3种树形的净光合值差异较大,开心形和疏散分层形为典型的不对称双峰型变化曲线,峰值均在12:30和17:30左右,并伴有"光合午休"现象;3种树形的蒸腾速率变化均和净光合呈正相关,在光合作用日进程中,蒸腾速率的下降变化主要受当地空气温度的影响;香梨气孔导度值以开心形最高;3种树形的胞间CO2浓度与净光合速率均呈负相关;综合净光合速率、蒸腾速率等参数指标可以看出,开心形和疏散分层形的光合性能较强;由于相对光照分布与树冠的相应层次呈显著正相关,所以在同种树形不同冠层上的光合能力以上层叶片最高。

In this paper the comparative research was carried out on photosynthetic and phisiological characteristics of 3 tree shapes of Korla Fragrant Pear with CB-1102 portable photosynthesis transpirometer.The result indicated that there is a significant difference of the net photosynthetic rate between the three tree shapes of Korla Fragrant Pear on a clear day,its value in both open-center shape and delayed-open central leader shape was a typical bimodal curve pattern,the peak value appeared in about 12：30 o＇clock and 17：30 o＇clock with photosynthetic Noon Break phenomenon at midday;The variation of transpiration rate presented positive correlation with the net photosynthetic rate,and the variation of transpiration rate,in the photosynthetic process,was mainly affected by the local atmosphere temperature;The stomatal conductance value of open-center shape was the highest;The intercellular CO2 concentration presented negative correlation with the net photosynthetic rate;For considering these parameters,the open-center shape and delayed-open central leader shape can improve the photosynthetic performance;Because the relatively light distribution presented positive correlation with crown corresponding level,the photosynthetic performance in the same tree shape and different canopies was the hightest.