不同类型小麦品种抽穗后光合生理性状的变化

Changes of Photosynthetic Characters in Wheat Varieties of Different Types after Heading

对三个典型春性、半冬性和冬性小麦品种抽穗后上三叶片净光合速率（Ｐｎ）、气孔导度（Ｃｓ）、胞间ＣＯ２浓度（Ｃｉ）、气孔阻力（Ｒｓ）、蒸腾速度（Ｒｔ）等５个光合生理性状的研究，抽穗后３个品种的净光合速率均呈下降趋势，春性和半冬性品种气孔导度、胞间ＣＯ２浓度、蒸腾速率上升，气孔阻力下降，而净光合速率的变化主要受非气孔因素影响。与春性和半冬性品种相反，冬性品种抽穗后气孔导度、胞间ＣＯ２浓度、蒸腾速率下降，气孔阻力增加，净光合速率的变化主要受气孔因素限制。５个光合生理性状在不同类型品种间均存有较大差异，同品种旗叶光合生理性状优于倒２叶，倒２叶优于倒３叶。

hree typical springness,half winterness and winterness wheat varieties were used to investigate the change and the difference of net photosynthetic rate(Pn),stomatal conductance to CO2(Cs),intercellular CO2 concentration (Ci),stomatal resistance (Rs) and transpiration rate (Rt) for upper 3 leaves after heading.The results were as follows:Pn of all the three varieties reduced after heading.Cs,Ci and Rt for springness and half wintermess varieties raised,Rs lowered down.The change of Pn in springness and half winterness varieties was influenced mainly by nonstomatal factors.On the contrary,Cs,Ci and Rt of winterness variety descended after heading,Rs ascended.The change of Pn in winterness wheat was limited mainly by the stomatal factorsThe five photosynthetic characters had larger variation among different types of wheat varieties.In general,the photosynthetic characteristics of same variety showed that the flag was superior to 2nd leaf from top,2nd leaf from top was superior to 3nd leaf from top.