水分胁迫对不同倍性小麦光合和水分利用影响

Exploration of Photosynthetic Characteristic and Water Use Efficiency of Different Wheat Ploid under Water Stress

在遮雨条件下采用称量法控制土壤水分,利用逐步干旱胁迫和复水条件,连续观测二倍体、四倍体和六倍体3种倍性小麦后的光合速率、蒸腾速率、单叶水分利用效率等的变化。结果表明,不同倍性小麦的光合速率都下降,下降速度为二倍体>四倍体>六倍体;水分胁迫对二倍体的蒸腾速率影响最大,对六倍体的蒸腾速率影响最小;水分胁迫对六倍体小麦的气孔导度影响小于四倍体和二倍体;水分胁迫结束后,3种倍性小麦品种的光合速率和蒸腾速率均能迅速恢复,以六倍体的气孔导度的恢复速率最快。水分胁迫下不同倍性小麦的水分利用效率均下降,以六倍体小麦下降程度最小,复水后3种倍性小麦均能快速恢复到几乎相同的水准。在相同的水分条件下,随着光强的增强,3种倍性小麦光反应动力曲线变化趋势相似,在400～1 200μmol/(m2.s)范围内,二倍体和六倍体小麦二者均显著高于四倍体。

Measuring the changes of photosynthetic rate, transpiration rate, the water use efficiency of dif- ferent wheat ploid under the conditions of different soil moisture contents. The results showed that all the photosynthetic rates decreased in drought process and the ranking of decreasing speed was that diploid〉 tetraploid〉hexaploid. The effect of water stress on transpiration rate of diploid was the greatest while the effect on transpiration rate of hexaploid was the smallest. The influence on stomatal conductance of hexa- ploid was the minimum. The water use efficiency decreased under water stress while the hexaploid de- creased minimum. After rewatering , the three wheat could quickly restore to almost the same level. In the nor- mal moisture conditions, with light intensity growing, the tendency of light kinetic curve was similar, and both diploid and hexaploid were significantly higher than tetraploid in the range of 400- 1 200 μmol/（m2 s）.