吉林省过去47年来水稻品种遗传改良过程中叶片光合指标的变化

 2006-2007年对吉林省1958年至2005年间育成的25个粳稻品种产量特性及叶片光合生理指标进行了比较。结果表明,粳稻品种产量随育成年代呈线性增加。 由1958年的6 671.9 kg/hm2增加至2005年的11 853.2 kg/hm2，平均每年增加110.2 kg/hm2，年增幅为1.65%。收获指数、成熟期和粒叶比随育成年代推延而增加且与产量呈显著正相关。随着品种产量的增加，单叶净光合速率显著增加且与产量呈正相关，光合速率增加主要是由于品种表观叶肉导度随育成年代推延而显著增加所致。同时，胞间CO2浓度/大气CO2浓度比值呈下降趋势，说明现代品种的光合作用存在一定的气孔限制作用。现代品种叶片的蒸腾速率的增幅大于光合速率的增幅，导致水分利用效率下降。因此，在未来水稻品种选育中，筛选高光合种质资源的同时要兼顾品种的水分利用特性。

Changes in Photosynthetic Indexes of Rice Varieties During Forty-seven Years of Genetic Improvement in Jilin Province, China

The photosynthetic characteristics of twenty five rice varieties released from 1958 to 2005 in Jilin Province, China were investigated in 2006 and 2007. The grain yield were linearly increased from 6 671.9 kg/hm2 in 1958 to 11 853.2 kg/hm2 in 2005, with an annual increase of 110.2 kg/hm2 (1.65%) in the 47 years. The harvest index, growth duration and spikelets/leaf area ratio were increased year by year and significantly correlated with grain yield. The photosynthetic rate of leaf increased and significantly and positively correlated with grain yield. The increase in photosynthetic rate was due to the increase in apparent leaf mesophyll conductance. The photosynthetic rate of modern variety was restricted by stomatal factors, due to the decrease of ratio of intercellular CO2 concentration to ambient CO2 concentration with year of release. The increase in transpiration rate exceed to that in photosynthetic rate, thus the water use efficiency descended. It is suggested that the improvement of water use should be paid attention to in future rice breeding.