缺磷对不同穗型小麦光合生理特性和产量的影响

采用石英砂培养的方法，研究了拔节期和挑旗期缺磷对大穗型小麦CA9325和多穗型小麦晋麦2号（JM2）生长后期旗叶的净光合速率（Pn）、蒸腾速率（Tr）、气孔导度（Cs）、细胞间隙CO2浓度（Ci）和气孔限制值（Ls）等光合生理性状，光合产物积累和产量构成的影响。结果表明：（1）缺磷降低两品种旗叶的净光合速率、蒸腾速率、气孔

Effects of P Deficiency on Photosynthetic Characters and Yield in Two Wheat Cultivars with Different Spike Types

Photosynthetic characters of flag leaf blade such as photosynthetic rate ( P n),transpiration rate ( T r),stomatal conductance ( C s),intercellular CO 2 concentration ( C i) and stomatal limitation ( L s), dry matter accumulation,and yield components per plant were studied on two wheat cultivars with different spike types,large-spike cultivar CA9325 and multi-spike cultivar JM2,with quartz sand culture. The P-deficient treatment was performed either at jointing stage or at flag leaf expanding stage. The results showed as follows: (1) Under P deficiency,the flag leaf blade photosynthetic rate ( P n),transpiration rate ( T r),stomatal conductance ( C s) and stomatal limitation ( L s) were gradually decreased,but intercellular CO 2 concentration ( C i) was enhanced,which suggested that the decreased photosynthetic rate might be controlled by non-stomatal limitation. (2) P deficiency did not affect the flag leaf areas,but reduced the dry matter accumulation and yield components per plant in two wheat cultivars. In comparison with CA9325,flag leaf areas of the P-sufficient JM2 were smaller,but its photosynthetic rate was higher. (3) At mature stage,the whole plant biomasses of JM2 in all treatments were significantly higher than those of CA9325. The grain yield of both cultivars grown under P-sufficient condition or P-deficiency started at flag leaf expanding stage did not show significant difference,but that of CA9325 grown under P deficiency commenced at jointing stage was decreased,compared with JM2. (4) The grain yield of CA9325 came mainly from of the number of grains per ear and thousand grain weight,but that of JM2 from ear number per plant and ear forming rate. P deficiency significantly decreased ear forming rate of JM2,and the number of grains per ear and thousand-grain weight of CA9325.