中文摘要：

以根系伤流液的重量作为根系活力的指标,研究了吉林省1923～2004年育成的22个大豆品种在盛花期（R2）,结荚期（R4）和鼓粒期（R6）根系伤流液重量的变化及其与功能叶片净光合速率（Pn）的关系。结果表明：根系伤流液重量与品种的育成年份呈正相关变化,但年度间表现存在差异,2009年没有达到显著水平,2010年在R2、R4和R6期达到显著或极显著水平,2 a伤流液重量的平均值在R4期与育成年份呈显著正相关,表明大豆品种的遗传改良导致了植株根系伤流液重量的增加。根系伤流液重量在R2期较低、R4期最大、R6期最小。R2和R4期根系伤流液重量均与Pn呈显著正相关。大豆R2和R4期根系伤流液重量可以作为功能叶片Pn的参考指标。

英文摘要：

In order to understand the changes of root bleeding sap weight（BSW）and the correlation between root activities and leaf net photosynthesis during the genetic improvement,root BSW and leaf net photosynthetic rate（Pn）were measured at flowering（R2）,pod bearing（R4）and seed filling（R6） stage with 22 soybean varieties bred in Jilin province from 1923 to 2004.The results showed that BSW was significantly or very significantly positive correlated with released years at R2,R4 and R6 stage in 2010,while didn＇t reach the significant level in 2009.Two years average of BSW showed significant positive correlation with released year at R4 stage.The genetic improvement of soybean cultivars had resulted in the increase of root BSW.The maximum and minimum root BSW was determined at R4 and R6 stage,respectively.Root BSW were positive correlated with net photosynthetic rate（Pn）significantly at R2 and R4 stage during the two years.The results suggested that root BSW at R2 and R4 stage could be as an reference index of leaf Pn.