大麦叶片表皮蜡质含量与抗旱性的关系研究

Study on the Relationship between Epicuticular Wax Content of Barley Leaves and Drought Resistance

【目的】了解植物叶片表皮蜡质含量与抗旱性的关系。【方法】对抗旱性不同的6个大麦品种进行干旱处理,对灌浆期的大麦旗叶、旗叶鞘表皮蜡质含量与7个重要的抗旱生理指标进行测定分析。【结果】干旱条件下不同大麦品种间的蜡质含量、相对含水量、叶绿素含量及气孔导度存在显著或极显著差异。抗性大麦品种的表皮蜡质含量及水分利用效率显著高于抗旱性弱的品种。表皮蜡质含量越高的品种,其蒸腾速率和胞间CO2浓度越低,水分利用效率越高。【结论】提高水分利用效率的途径主要是通过降低蒸腾速率。干旱胁迫下叶片失水,气孔开度减小甚至趋于关闭,而高蜡质含量品种的气孔导度更小,阻力增大,降低蒸腾速率,减少水分散失,维持较高含水量,提高植株抗旱性。

[ Objective ] In order to study the relationship between the leaf epicuticular wax content and drought resistance in barley plant. [ Method ] 6 cultivars possessing different drought- resistance were employed under drought conditions in this experiment. With no irrigation during the whole period, analysis was carried out of the correlation between epicuticular wax content and other 7 drought resistant physiology traits of flag leaf, including water us~ efficiency relative water content, chlorophyll, net photosynthetic rate, transpiration rate, stomata conductance, intercellular CO2 concentration at late grain -filling stage. [ Result] The results showed as follows： the difference of epicuticular wax content, relative water content, chlorophyll and stomata conductance of leaves were significant in different barley varieties under drought stress condition. Epieuticular wax content and water use efficiency of resistance barley varieties were significantly higher than those of the varieties with weak drought resistance. The higher epicuticular wax content of flag leaf was, the lower transpiration rate would be, and the lower intercellular C02 concentration, and higher water use efficiency. [ Conclusion] The result showed that improving water use efficiency should mainly focus on the pathway to reduce transpiration rate. Epicuticular wax content of leaf can decrease stomata transpiration, increase water use efficiency, thus enhancing drought resistance by adjusting stomata conductance mechanism under drought conditions.