库尔勒香梨光合特性的初步研究

Preliminary Study of Photosynthetic Characteristics on Korla Fragrant Pear

【目的】了解库尔勒香梨光合生理特性及其相关变化规律。【方法】利用Li-6400光合作用测定系统测定库尔勒香梨两种树形的光合特征参数,通过试验测得光合色素含量以及比叶重,进行分析探讨。【结果】两种树形的光合色素含量存在差异,疏散分层形树的Chla含量极显著大于开心形,Chla+Chlb值在25.88～38.96 mg/cm2,而两种树形之间的比叶重均值相差不大;开心形和疏散分层形的光补偿点(LCP)分别是28.75、33.22μmol/(m2.s),在光强为1 090μmol/(m2.s)时开心形树达到光饱和点,对应最大净光合速率值为18.61μmol/(m2.s),低于疏散分层形的饱和光强1 150μmol/(m2.s);开心形和疏散分层形的CO2浓度补偿点分别是63.55和57.04μmol/mol,两种树形的羧化效率(CE)分别为0.039 5、0.036 6。在CO2浓度达到1 135μmol/mol时,开心形的净光合速率达到最大值,为29.34μmol/(m2.s),疏散分层形CO2饱和点(CSP)为1 165μmol/mol。【结论】疏散分层形树对强光以及对CO2的利用率较高。

【Objective】To study the photosynthesis characteristics and variation law of Korla Fragrant Pear.【Methods】Measure the photosynthesis parameters of two type tree shape of Korla Fragrant Pear by Li-6400 and the photosynthetic pigments content and specific leaf weight by experiment methods,discussing the data results.【Result】The results showed that the photosynthetic pigments showed significant differences.The delayed-open central leader shape in content of chlorophyll was significantly higher than that of the open center shape.The total content of chlorophyll changed from 25.88 mg/cm2 to 38.96 mg/cm2,but there was no difference in specific leaf weight of different tree shape;The light compensation point of the open center shape and delayed-open central leader shape were 28.75 μmol/m2·sand 33.22 μmol/m2·s.The net photosynthetic rate of open center shape was 13.36 μmol/m2·s when reaching its light saturation point 109 0 μmol/m2·s,which was lower than that of delayed-open central leader shape 1 150 μmol/m2·s;The CO2 compensation concentration point of open center shape and delayed-open central leader shape were 63.55 μmol/mol and 57.04 μmol/mol,the carboxylation efficiency of both shapes were 0.039 5 and 0.036 6.The net photosynthetic rate of open center shape reached its peak value 29.34 μmol/m2·s when CO2 concentration reached 1 135 μmol/m2·s.The CO2 saturation concentration of delayed-open central leader shape was 1 165 μmol/m2·s.【Conclusion】The delayed-open central leader shape of light and carboxylation use efficiency was higher than that of the open center shape.