Zhao Li, He Jianxin, Wang Xiaomin, Zhang Lixin
School of Life Science, Lanzhou University, Lanzhou 730000, China.
J Plant Physiol. 2008 Feb;165(2):182-91. doi: 10.1016/j.jplph.2007.03.002. Epub 2007 May 11.
Dune reed (DR) is the more tolerant ecotype of reed to environmental stresses than swamp reed (SR). Under osmotic stress mediated by polyethylene glycol (PEG-6000), the suspension culture of SR showed higher ion leakage, and more oxidative damage to the membrane lipids and proteins was observed compared with the relatively tolerant DR suspension culture. Treatment with sodium nitroprusside (SNP) can significantly alleviated PEG-induced ion leakage, thiobarbituric acid reactive substances (TBARS) and carbonyl contents increase in SR suspension culture. The levels of H(2)O(2) and O(2)(-) were reduced, and the activities of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) were increased in both suspension cultures in the presence of SNP under osmotic stress, but lipoxygenase (LOX) activity was inhibited. 2-(4-carboxy-2-phenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (PTIO), a specific Nitric oxide (NO) scavenger, blocked the SNP-mediated protection. Depletion of endogenous NO with PTIO strongly enhanced oxidative damage in DR compared with that of PEG treatment alone, whereas had no effect on SR. Moreover, NO production increased significantly in DR while kept stable in SR under osmotic stress. Taken together, these results suggest that PEG induced NO release in DR but not SR can effectively protect against oxidative damage and confer an increased tolerance to osmotic stress in DR suspension culture.
沙丘芦苇（DR）是芦苇中比沼泽芦苇（SR）对环境胁迫耐受性更强的生态型。在聚乙二醇（PEG - 6000）介导的渗透胁迫下，SR的悬浮培养物显示出更高的离子渗漏，并且与耐受性相对较强的DR悬浮培养物相比，观察到对膜脂和蛋白质的氧化损伤更大。用硝普钠（SNP）处理可显著减轻PEG诱导的SR悬浮培养物中的离子渗漏、硫代巴比妥酸反应性物质（TBARS）和羰基含量的增加。在渗透胁迫下，在SNP存在的情况下，两种悬浮培养物中的H₂O₂和O₂⁻水平降低，超氧化物歧化酶（SOD）、过氧化氢酶（CAT）和抗坏血酸过氧化物酶（APX）等抗氧化酶的活性增加，但脂氧合酶（LOX）活性受到抑制。2 -（4 - 羧基 - 2 - 苯基）- 4,4,5,5 - 四甲基咪唑啉 - 1 - 氧基 - 3 - 氧化物（PTIO），一种特异性一氧化氮（NO）清除剂，阻断了SNP介导的保护作用。与单独的PEG处理相比，用PTIO耗尽内源性NO会强烈增强DR中的氧化损伤，而对SR没有影响。此外，在渗透胁迫下，DR中的NO产生显著增加，而SR中的NO保持稳定。综上所述，这些结果表明PEG诱导DR而非SR释放NO，这可以有效保护其免受氧化损伤，并使DR悬浮培养物对渗透胁迫的耐受性增强。
