【摘要】 在田间条件下,研究12个大豆品种两个生育时期的叶片光合速率（P_A）、气孔导度（g_s）、叶肉导度（g_m）、气孔内CO₂浓度（C_i）和蒸腾速率（TR）。结果表明,上述5个性状均有显著的品种间差异,并且鼓粒中后期明显大于开花前后。各性状的平均数在鼓粒中后期均极显著低于开花前后。P_A与g_s的关系,随生育期表现不同,在开花前后,可以配合成一条三次多项式曲线,并显示出一个最大的P_A值,而在鼓粒中后期则呈显著的线性关系。P_A与g_m在两个时期一致地呈一条二次多项式曲线,曲线相关指数达0.99。P_A与TR和C_i在两个时期均呈线性关系,与TR为极显著正相关,与C_i为极显著负相关。通径分析表明,影响P_A的主要因素在开花前后为g_m和C_i,但到鼓粒中后期,g_s也成为一个重要的限制因素。更多还原

【Abstract】 Five traits, leaf apparent photosynthetic rate (PA ), stomatal conductance (gs), mesophyll conductance (gm), intercelluar CO2 concentration (Ci) and transpiration rate (TR) were determined by using 12 soybean cultivars at two growth stages in the field-grown conditions. The significant cultivar differences in all the five traits, were observed at two stages, around flowering stage (AFS) and middle and late seed-filling stage( SFS), at which the variation among cultivars appeared to be much larger at the latter than at the former. And between two stages, the five traits performed to be very significantly lower at AFS than at SFS. The different relationships of PA with gs at AFS and SFS were shown that at AFS a cubic polynomial curve might be fitted giving the maximum PA at gs =2.34 cm·s-1, but the significant linear relation was observed at SFS. The relation of PA to gm at two stages showed a combined quadratic polynomial curve with correlation ratio of as high as 0.99. PA was significantly and positively correlated with TR, and negatively with Ci at two stages. Path analysis suggested that the main factors directly affecting PA at AFS were gm and Ci, but at SFS, gs also became a key limiting factor for increasing PA .更多还原