干旱对关中地区不同年代小麦品种旗叶光合特性的影响

以陕西关中地区70年间大面积推广的冬小麦品种为材料,研究了干旱胁迫对冬小麦花后旗叶光合特性和产量的影响。结果表明,随着小麦品种的更替,抗旱性逐步增强,干旱胁迫下20世纪50年代以前品种五指麦、碧蚂1号比适宜水分条件下分别减产18.2%、38.3%,而90年代后品种小偃22仅减产2.3%。不同品种小麦收获前期旗叶净光合速率、蒸腾速率、水分利用效率、气孔导度受干旱影响均有所下降,但旗叶胞间CO2浓度则表现为增加趋势,碧蚂1号、小偃22号花后各阶段旗叶气孔导度平均降低了5%、18%,旗叶胞间CO2浓度则提高了9%、8%,说明干旱胁迫下花后旗叶净光合速率的降低并非是由气孔导度降低引起的。

Effect of drought stress on photosynthesis characteristics in flag leaf of wheat cultivars in different years in the central Shaanxi plain

Winter wheat cultivars which have been popularized with large area in the central Shaanxi plain in recent 70 years were used as materials to study the effect of post-anthesis drought stress on photosynthesis characteristics in flag leaf.The results indicated that the drought resistance was increased with the replacement of wheat cultivars,under drought stress the yield of the wheat cultivars Wuzhi and Bima 1 which were the wheat cultivars before 1950 s was decreased by 18.2% and 38.3% compared with that under optimal water condition,but the yield of Xiaoyan 22 after 1990s was only decreased by 2.3%.The rate of photosynthesis and transpiration,stomatal conductance,single leaf water use efficiency in flag leaf under drought stress all decreased except the Ci which showed increasing trend before harvesting,the Gs in flag leaf of Bima 1 and Xiaoyan 22 averagely decreased by 5% and 18% on each stage after anthesis,but the Ci increased by 9% and 8%,which showed that the decrease of Pn in flag leaf was not caused by the decrease of Gs under drought stress.