EFFECTS OF LIMITED IRRIGATION AND DIFFERENT FERTILIZATION WAYS ON SOME PHOTOSYNTHETIC FUNCTIONS OF FLAG LEAVES IN WINTER WHEAT

Modulated chlorophyll fluorescence induction kinetics technique was used to investigate the effects of limited irrigation after the spring and different fertilization ways on some photosynthetic functions of flag leaves from different winter wheat cultivars. The experimental results showed that, when the same amount of the total fertilizer was used, photosynthetic functions of flag leaves from different winter wheat cultivars variously responded to the two ways of cultivation, one was to irrigate at jointing stage and grain filling stage with part of urea(150 kg/hm2) used as topdressing at jointing stage, another was not to irrigate while all fertiilizer was used as base fertilizer. PSⅡ activity, the efficiency of primary conversion of light energy and overall photochemical quantum yield of PSⅡ(Yield), photochemical quenching coefficient(q P), the apparent photosynthetic electron transport rate(ETR) of the flag leaves in 76 Xuanxi, especially 4041 were raised and the dissipation of the non radiation energy was reduced by the irrigation after spring and the part of the urea as jointing fertilizer. However, the above?mentioned photosynthetic functions of the flag leaves in the Shannong 45 of drought resistant cultivar were not improved by this treatment. The probability of reduced irrigation frequency after the spring and all fertilizer as base fertilizer was discussed in this paper.