复水对水分胁迫条件下糜子生长的补偿效应

为明确复水对糜子叶片衰老与活性氧代谢的影响,建立糜子抗旱节水栽培技术体系,以榆糜2号为试验材料,采用盆栽控水方式,研究复水对水分胁迫条件下糜子叶片衰老与活性氧代谢特征的动态变化。结果表明,随胁迫程度的加剧和胁迫时间的延长,糜子功能叶片自下而上依次衰老,其叶绿素含量、可溶性蛋白质含量、超氧化物歧化酶(SOD)和过氧化物酶(POD)活性逐渐降低,丙二醛(MDA)含量持续上升。复水后,中度水分胁迫拔节期复水效果最佳,糜子顶三叶叶绿素含量、可溶性蛋白质含量、SOD和POD活性分别比对照高出7.65%、4.20%、5.30和3.52%,表现出超补偿效应;开花期复水产生了等量补偿效应;重度水分胁迫条件下,拔节期复水对糜子叶片SOD、POD产生了部分补偿效应,对叶绿素、可溶性蛋白质和MDA含量产生了等量补偿效应;开花期复水后各指标的补偿效果不明显。相关分析表明,糜子产量与生育后期各功能叶片的叶绿素含量、可溶性蛋白质含量、SOD活性呈极显著正相关,与POD活性呈显著正相关,MDA含量与产量呈现显著负相关。拔节期复水对中度水分胁迫下糜子生长的补偿效应最佳。

Compensation effect of rewatering on the growth of broomcorn millet under water stress

The aim of this paper is to study the effects of rewatering on the leaf senescence mechanism and active oxygen metabolic characteristics of broomcorn millet after water stress, thus to provide a theoretical basis for water saving cultivation techniques of broomcorn millet.Using Yumi 2 as the material, a pot experiment was conducted.It was found that as the stress level intensified and the stress time prolonged, the leaves of broomcorn millet aged from the bottom to the top, the contents of chlorophyll and soluble protein, and the activities of SOD and POD of the leaves gradually decreased, while the content of MDA continuously increased.Rewatering at the jointing stage after moderate water stress showed an over-compensation effect which was characterized by the contents of chlorophyll, soluble protein and the activities of SOD and POD of the top three leaves of broomcorn millet that were 7.65%, 4.20%, 5.30% and 3.52% higher than CK respectively.Rewatering at the flowering stage after moderate water stress had a contour compensation effect on these indexes.Rewatering at the jointing stage after severe water stress had a partial compensation effect on the activities of SOD and POD of the top three leaves, and had a contour compensation effect on the contents of chlorophyll, soluble protein and MDA of the top three leaves, while the compensation effect on these indexes of rewatering at the flowering stage after severe water stress was not significant.According to the results of the correlative analysis, there were high significant positive correlations between the yield and the contents of chlorophyll and soluble protein and the SOD activity, a significant positive correlation between the yield and the POD activity, and a significant negative correlation between the yield and MDA content of the tested leaves of mature period.Therefore, it can be concluded that rewatering at the jointing stage after moderate water stress had the best compensation effect on broomcorn millet.