缺磷对不同穗型小麦光合生理特性和产量的影响

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

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CA932 5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、气孔导度和气孔限制值 ;相反 ,细胞间隙CO2 浓度呈上升趋势 ,说明光合速率的降低受非气孔因素的限制 ;(2 )两种缺磷处理不影响两品种的旗叶面积 ,但降低了干物质的积累量和籽粒产量 ;供磷时 ,JM2的旗叶面积虽小 ,但光合速率较高 ;(3)成熟期 ,供磷和两种缺磷处理的JM2植株干重均显著高于CA932 5 ,除拔节期缺磷的JM2籽粒产量明显高于CA932 5外 ,前者挑旗期缺磷及供磷的籽粒产量与后者比差异不显著 ;(4 )大穗型CA932 5主要靠增加穗粒数和千粒重获得高产 ,而多穗型JM2由较高的单株成穗数和成穗率来提高产量。缺磷显著降低JM2的单株成穗数及CA932 5的穗粒数和千粒重。

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.