ABSTRACT

Drought is the main factor restricting the yield of winter wheat in large arid and semiarid areas. The balance between water conservation and photosynthesis is important for breeding drought-resistant wheat cultivars. Besides, the mechanisms for drought resistance in many drought-resistant wheat cultivars have not been completely explored. To elucidate the above questions, the photosynthetic performance of drought-resistant wheat cultivar LH6 and drought-sensitive wheat cultivar ZM7698 were measured under drought treatment with different time and light intensity. The results showed that the photosystem II activity, electron transport from Q_A to Q_B, carboxylation and ribulose-1,5-bisphosphate regeneration process in LH6 were inhibited less than in ZM7698 in drought conditions, which mainly contributed to the nonstomatal inhibition of photosynthesis. In normal water conditions, the transpiration rate in LH6 was higher and water use efficiency was lower than that of ZM7698, which showed no water conservation effects. In drought conditions, LH6 had a higher photosynthetic rate and stomatal conductance by maintaining the water-absorbing capacity of the roots. In conclusion, the photosynthetic apparatus of LH6 is drought resisting but costs more water; both water conservation and photosynthetic capability should be considered during breeding drought-resistant wheat cultivars in the future.

抽象的

在干旱和半干旱地区，干旱是限制冬小麦单产的主要因素。保水和光合作用之间的平衡对于育种抗旱小麦品种非常重要。此外，许多抗旱小麦品种的抗旱机理尚未完全探讨。为了阐明上述问题，在不同的时间和光照强度下，测量了抗旱小麦品种LH6和干旱敏感小麦品种ZM7698的光合性能。结果表明，光系统II的活性，电子从Q _A到Q _B的传递在干旱条件下，LH6的羧化和核糖-1,5-二磷酸核糖再生过程受到的抑制作用小于ZM7698，这主要是由于非气孔抑制了光合作用。在正常水条件下，LH6的蒸腾速率较高，而水分利用效率则低于ZM7698，这表明没有节水作用。在干旱条件下，LH6通过保持根系的吸水能力而具有较高的光合速率和气孔导度。总之，LH6的光合设备具有抗旱性，但耗水量更多。今后在抗旱小麦品种育种中应同时考虑节水和光合能力。