Recent studies have demonstrated that exogenous polyamines have protective effects under various stress condition. A broader understanding of the role of the polyamine pool fine regulation and the alterations of polyamine-related physiological processes could be obtained by comparing the stress effects in different genotypes. In this study, the impact of pre-treatment with putrescine in response to osmotic stress was investigated in the drought-tolerant Katya and drought-sensitive Zora wheat (Triticum aestivum) cultivars. Photosynthetic performance, in vivo thermoluminescence emission from leaves, leaf temperature, polyamine and salicylic acid levels, contents of osmoprotectants, and activities of antioxidant enzymes in the leaves were investigated not only to reveal differences in the physiological processes associated to drought tolerance, but to highlight the modulating strategies of polyamine metabolism between a drought-tolerant and a drought-sensitive wheat genotype. Results showed that the tolerance of Katya under osmotic stress conditions was characterized by higher photosynthetic ability, stable charge separation across the thylakoid membrane in photosystem II, higher proline accumulation and antioxidant activity. Thermoluminescence also revealed differences between the two varieties - a downshift of the B band and an increase of the afterglow band under osmotic stress in Zora, providing original complementary information to leaf photosynthesis. Katya variety exhibited higher constitutive levels of the signaling molecules putrescine and salicylic acid compared to the sensitive Zora. However, responses to exogenous putrescine were more advantageous for the sensitive variety under PEG treatment, which may be in relation with the decreased catabolism of polyamines, suggesting the increased need for polyamine under stress conditions. This article is protected by copyright. All rights reserved.

中文翻译：

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腐胺预处理对耐旱和干旱敏感小麦幼苗渗透胁迫响应的影响

最近的研究表明，外源性多胺在各种应激条件下具有保护作用。通过比较不同基因型的应激效应，可以更广泛地了解多胺池精细调节的作用和多胺相关生理过程的改变。在这项研究中，在耐旱的 Katya 和对干旱敏感的 Zora 小麦 (Triticum aestivum) 品种中研究了腐胺预处理对渗透胁迫的影响。研究了叶片的光合性能、体内热释光发射、叶片温度、多胺和水杨酸水平、渗透保护剂的含量以及叶片中抗氧化酶的活性，不仅揭示了与耐旱性相关的生理过程的差异，但要强调耐旱和干旱敏感小麦基因型之间多胺代谢的调节策略。结果表明，Katya在渗透胁迫条件下的耐受性具有较高的光合能力、稳定的光系统II类囊体膜电荷分离、较高的脯氨酸积累和抗氧化活性。热释光还揭示了这两个品种之间的差异——在 Zora 渗透胁迫下，B 带的下降和余辉带的增加，为叶片光合作用提供了原始的补充信息。与敏感的 Zora 相比，Katya 品种表现出更高的信号分子腐胺和水杨酸的组成水平。然而，外源性腐胺的反应对 PEG 处理下的敏感品种更有利，这可能与多胺分解代谢降低有关，表明在压力条件下对多胺的需求增加。本文受版权保护。版权所有。