Abstract

The role of nitric oxide and its functional relations to reactive oxygen species (ROS) and calcium are studied in relation to the stress-protective effects of the polyamine putrescine in wheat seedlings (Triticum aestivum L.) subjected to heat stress. The treatment of seedlings with 1 mM putrescine causes a rapid, transient rise in the NO content in roots in the first 24 h, which peaks 1 h after the beginning of exposure. It was noted a doubling of the activity of diamine oxidase (DAO) and the reduction of nitrate reductase activity in roots by 25–30%. The DAO inhibitor aminoguanidine completely eliminated the putrescine-induced increase in the NO content. The increase in the DAO activity and NO content was also eliminated by the treatment of seedlings with the calcium antagonists ethylene glycol-bis(2-aminoethylether)-N,N,N′,N′-tetraacetic acid (EGTA) and neomycin. The scavenger of nitric oxide 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (PTIO) completely counteracted the effect of hydrogen peroxide increase in weat seedlings roots treated by putrescine. In the meantime, treatment with dimethylthiourea, a hydrogen peroxide antagonist, only slightly reduced the putrescine-induced rise in NO content in the roots. The NO, ROS, and calcium antagonists eliminated the protective effect of putrescine during heat stress, which was determined by the intensity of lipid peroxidation and seedling survival. We draw a conclusion concerning the role of nitric oxide synthesized via the oxidative pathway and its functional relations to ROS and calcium ions in the stress-protective effect of putrescine in plant objects.

中文翻译：

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NO合成修饰在腐胺对热应激小麦幼苗保护作用中的作用

摘要

研究了一氧化氮的作用及其与活性氧 (ROS) 和钙的功能关系，以及多胺腐胺在小麦幼苗中的胁迫保护作用 ( Triticum aestivumL.) 承受热应力。用 1 mM 腐胺处理幼苗会导致根中 NO 含量在最初 24 小时内迅速、瞬时升高，在开始暴露后 1 小时达到峰值。注意到二胺氧化酶 (DAO) 的活性翻了一番，根中硝酸盐还原酶的活性降低了 25-30%。DAO 抑制剂氨基胍完全消除了腐胺诱导的 NO 含量增加。用钙拮抗剂乙二醇-双（2-氨基乙醚）- N , N , N ', N处理幼苗也消除了DAO活性和NO含量的增加'-四乙酸（EGTA）和新霉素。一氧化氮清除剂 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (PTIO) 完全抵消了腐胺处理的湿幼苗根部过氧化氢增加的影响。同时，用二甲基硫脲（一种过氧化氢拮抗剂）处理仅略微降低了腐胺诱导的根中 NO 含量的升高。NO、ROS 和钙拮抗剂在热应激过程中消除了腐胺的保护作用，这是由脂质过氧化的强度和幼苗存活率决定的。我们得出了关于通过氧化途径合成的一氧化氮的作用及其与 ROS 和钙离子的功能关系在腐胺对植物对象的胁迫保护作用中的作用的结论。