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在大田自然干旱条件下旱作处理，冬小麦生育后期旗叶光合速率仍可达１４２４μｍｏｌＣＯ２·ｍ－２·ｓ－１；在叶片水势达－１８～－２１ＭＰａ条件下，旗叶ＲｕＢｐ羧化酶活性可达２０～２３μｍｏｌＣＯ２·ｍｉｎ－１·ｇ－１ｄｗ；浇水处理小麦植株旗叶光合速率为１５１５μｍｏｌＣＯ２·ｍ－２·ｓ－１，水势达－１６５～－１８ＭＰａ条件下，旗叶ＲｕＢｐ羧化酶活性可达２２～２５μｍｏｌＣＯ２·ｍｉｎ－１·ｇ－１ｄｗ；表明在一定干旱条件下，旗叶ＲｕＢｐ羧化酶不是光合速率主要的限制因素，其受干旱影响程度较小。另外，在自然干旱条件下，地上部光合器官旗叶、旗叶鞘、旗叶节间及芒对籽粒的贡献可达４４８％；而浇水处理为４０２％。在生育后期，地上部１４Ｃ光合产物向地下根系运输的比例两处理均为２％左右，但旱作处理１２０～２００ｃｍ土层范围内根系所占有的１４Ｃ产物量占地下根系１４Ｃ产物总量的比率达８３４％，而浇水处理则只有３６％。这些特性对保证旱作栽培冬小麦生育后期的正常生长发育是十分有益的。
Under drought conditions in the field, the flag leaf photosynthetic rate could reach 1424μmolCO 2 · m-2 · s-1 at the later growth stage of winter wheat under the condition of leaf water potential of -18 ~ -21MPa, The activity of RuBp carboxylase reached 20 ~ 23μmolCO 2 · min-1 · g-1dw. The flag leaf photosynthetic rate of water-stressed wheat was 1515μmolCO 2 · m-2 · s-1 and the water potential was -165 ~ -1 The activity of RuBp carboxylase was up to 22-25 μmolCO2 · min-1 · g-1dw under 8 MPa condition, indicating that the flag leaf RuBp carboxylase was not the main limiting factor of photosynthetic rate under certain drought conditions, Less impact. In addition, under natural drought conditions, the contribution of flag leaves, flag leaf sheaths, flag leaf nodes and shoots to grain in above-ground photosynthetic organs reached 448%, while watering treatment was 402%. In late growth stage, the ratio of 14C photosynthate to aboveground underground transportation was about 2% in both treatments, but the ratio of 14C products occupied by root system to total 14C products in underground roots within the range of 120 ~ 200cm Up to 8 34%, while watering only 3 6%. These characteristics are very helpful to ensure the normal growth and development of winter wheat in dry cultivation.