Abstract:

【Objective】 This project aims to study the changes of photosynthetic characteristics, resistance indexes and plant hormones of upland cotton GhCIPK6 transgenic offspring under high temperature stress in order to lay a foundation for upland cotton to respond to high temperature stress.【Methods】 In this experiment, the overexpression of ghc1pk6 transgenic offspring, RNAi and control wild type were constructed as materials. The physiological and biochemical indexes were measured at 4 h, 12 h, 24 h and 48 h by greenhouse culture.【Results】 Through the comparison of seedling leaves, it was found that the overexpressed leaves had turned yellow and a large number of spots appeared under high temperature, followed by wild-type leaves, and RNAi leaves only slightly turned yellow;In the photosynthetic characteristics, under high temperature stress, with the extension of time, the net photosynthetic rate, stomatal conductance, transpiration rate and intercellular CO₂ concentration decreased first and then increased. The overexpression materials increased slowly in photosynthetic indexes, RNAi and wild-type increased rapidly, and the change trend of chlorophyll relative content was slow; Among the resistance indexes, under high temperature stress, overexpression increased gradually with the extension of time, SOD content increased first and then decreased and then increased, pod content showed a high level, MAD content in RNAi increased first and then decreased, SOD content increased first and then decreased, pod content increased slowly, soluble protein content and Pro content showed a relatively high level in the whole period; In plant hormones, with the extension of time, the content of IAA in overexpression materials showed an upward trend, the content of ABA was low, the content of JA first increased slowly and then decreased, SA first increased and then decreased, the content of IAA in RNAi materials gradually increased, the content of ABA first increased and then decreased, the content of JA first increased and then decreased, the content of SA first decreased and then increased and then decreased, the content of IAA in wild type first increased and then decreased, and the content of ABA first increased and then decreased and then increased, JA content first increased and then decreased, SA content first decreased and then increased and then decreased. The resistance to high temperature of the three materials from strong to weak was RNAi, wild-type and overexpression.【Conclusion】 The comprehensive results show that under high temperature, the harm of stress can be reduced by increasing transpiration rate, the growth of plants can be actively regulated by increasing auxin content, and the osmotic regulation ability of cells can be improved to reduce the damage of cells.

Key words: upland cotton; high temperature stress; physiological and biochemical analysis

摘要：

【目的】研究高温胁迫条件下陆地棉GhCIPK6转基因后代幼苗体内光合特性指标、抗性指标、植物激素的变化,为陆地棉响应高温胁迫奠定基础。【方法】以构建GhCIPK6转基因后代超表达、RNAi和对照野生型为材料,采用温室培养的方法,在4、12、24、48 h测定生理生化指标。【结果】通过幼苗叶片比较,高温下超表达叶片已经发黄,出现大量斑点,野生型叶片发黄程度次之,RNAi叶片只轻微发黄;光合特性中,高温胁迫下随着时间延长净光合速率、气孔导度、蒸腾速率、细胞间CO₂浓度均呈先下降后上升,超表达材料在光合指标中增幅较慢,RNAi和野生型增幅较快,叶绿素相对含量变化趋势缓慢;在抗性指标中,高温胁迫下,超表达随着时间延长MAD含量逐渐增加,SOD含量呈先增加后降低后上升,POD含量表现出较高水平,RNAi中MAD含量呈先增加后下降,SOD含量呈先上升后下降,POD含量缓慢增加,可溶性蛋白含量和Pro含量在整个时期相对呈现较高的水平;植物激素中,随着时间延长超表达材料IAA含量呈上升趋势,ABA含量较低,JA含量先缓慢增加后下降,SA先增加后下降,RNAi材料中IAA含量逐渐上升,ABA含量呈先增加后下降,JA含量先增加后下降,SA含量先下降后上升后下降,野生型中IAA含量先上升后下降,ABA含量呈先上升再下降后上升,JA含量先增加后下降,SA含量先下降后上升后下降。3种材料抗高温能力由强到弱为RNAi,野生型,超表达。【结论】在高温下可通过提高蒸腾速率来减弱逆境胁迫的危害,提高生长素含量来积极调控植物生长,提高细胞的渗透调节能力来减轻细胞遭受的损伤。

关键词: 陆地棉, 高温胁迫, 生理生化