| rrigation treatments are conducted in different growth stages of winter wheat to study their effects on winter wheat canopy structure,photosynthetic character and yield.The results show that two irrigation treatment(in winter period and jointing stage) the chlorophyll content and LAI of winter wheat always maintain a high level in the whole growth period,while they show an inverted “V”-type in the early filling stage and flowering stage.The effects of irrigation treatments on the DIFN are in opposite to the trends of LAI changes.Two irrigation treatment the winter wheat flag leaf net photosynthetic rate,stomatal conductance and transpiration rate increase more significantly compared to one irrigation treatment(in winter or jointing stage),and intercellular CO2 concentration decreases.The yield of all three varieties of P12,138 and M808 reaches the maximum in the two irrigation treatment,reaching 5 045 kg/hm2,5 516 kg/hm2 and 5 479 kg/hm2, respectively. |