Abstract

Arabidopsis thaliana Heynh. (L.) plants of the Columbia ecotype (Col-0) and its ethylene-insensitive etr1-1 (ethylene resistant 1) and ein2-1 (ethylene insensitive 2) mutants were studied. The plants were compared in respect to their cold tolerance conferred by cold acclimation. The tolerance to negative temperature increased in all the three genotypes after 5-day cooling of the plants at 2°C. Meanwhile, a quantitative difference was observed between them: the Col-0 plants survived better than the mutants, and the electrolyte leakage from the tissues reached 50% at higher (by 1°C and more) temperature in the hardened mutants than in the Col-0. Only the mutants manifested the increased lipid peroxidation over the hardening period; this indicates ROS production and general oxidative stress. From this point, we speculated that the tested Arabidopsis genotypes are different in the efficiency of their antioxidant systems. For testing, the total activities of the chief antioxidant enzymes superoxide dismutase (SOD) and catalase, including their isoenzymes, were monitored in the course of hardening. The total SOD activity was found to be lower in the mutants than in the Col-0 both at the normal growing temperature and over the whole time of the cold hardening. The isozyme analysis revealed the link of the reduced total SOD activity of the mutants with the reduced activity of their Cu/Zn-SOD isoforms at 22°C and at the beginning of the hardening. This relationship was supported by the lower relative content of the CSD1 and CSD2 gene transcripts of Cu/Zn-SOD in the mutants in comparison with the Col-0. The decrease in the total catalase activity was also observed and would be ascribed to the lowered activity of the CAT2 isoform. The reported results evidence to the principal feasibility of the ethylene signaling control of the Cu/Zn-SOD and catalase activities associated with the cold acclimation of Arabidopsis.

中文翻译：

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拟南芥植物及其乙烯不敏感突变体的低温耐受性差异与抗氧化酶活性有关

摘要

拟南芥Heynh 。哥伦比亚生态型（Col-0）及其对乙烯不敏感的etr1-1（抗乙烯1）和ein2-1的植物（乙烯不敏感2）突变体进行了研究。对植物进行冷驯化后的耐寒性进行了比较。在2°C下将植物冷却5天后，所有三种基因型对负温度的耐受性均增加。同时，观察到它们之间存在数量差异：Col-0植物比突变体存活得更好，并且在硬化的突变体中比Col更高的温度下（高于1°C和更高），组织中的电解质泄漏达到50％。 -0。只有突变体在硬化期间表现出增加的脂质过氧化作用。这表明ROS的产生和一般的氧化应激。从这一点出发，我们推测经过测试的拟南芥基因型的抗氧化系统效率不同。为了进行测试，在硬化过程中监测了主要抗氧化酶超氧化物歧化酶（SOD）和过氧化氢酶的总活性，包括其同工酶。发现在正常生长温度和整个冷硬化过程中，突变体的总SOD活性均低于Col-0。同工酶分析显示，在22°C和硬化开始时，突变体的总SOD活性降低与其Cu / Zn-SOD同工型的活性降低有关。CSD1和CSD2的相对含量较低支持了这种关系与Col-0相比，突变体中Cu / Zn-SOD的基因转录本。还观察到总过氧化氢酶活性的降低，这归因于CAT2同工型的活性降低。报告的结果证明了乙烯信号控制拟南芥冷驯化相关的Cu / Zn-SOD和过氧化氢酶活性的主要可行性。