库尔勒香梨光合特性的初步研究

摘要

[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 jxmol/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 C02 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/m · s when CO2 concentration reached 1 135 (xmol/m2 · s. The C02 saturation concentration of delayed -open central leader shape was 1 165 (xmol/m2 · s. [ Conclusion ] The delayed - open central leader shape of light and carboxylation use efficiency was higher than that of the open center shape.%[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、33.22 μmol/(m2·s),在光强为1 090 μmol/( m2·s)时开心形树达到光饱和点,对应最大净光合速率值为18.61 μmol/(m2·s),低于疏散分层形的饱和光强1 150 μmol/( m2·s)；开心形和疏散分层形的CO2浓度补偿点分别是63.55和57.04 μmol/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1 135 μmol/mol时,开心形的净光合速率达到最大值,为29.34 μmol/( m2·s),疏散分层形CO2饱和点(CSP)为1 165 μmol/mol.[结论]疏散分层形树对强光以及对CO2的利用率较高.