Ethylene is considered one of the most important plant hormones orchestrating plant responses to flooding stress. However, ethylene may induce deleterious effects on plants, especially when produced at high rates in response to stress. In this paper, we explored the effect of attenuated ethylene sensitivity in the Never ripe (Nr) mutant on leaf photosynthetic capacity of flooded tomato plants. We found out that reduced ethylene perception in Nr plants was associated with a more efficient photochemical and non-photochemical radiative energy dissipation capability, in response to flooding. The data correlated with retention of chlorophyll and carotenoids content in flooded Nr leaves. Moreover, leaf area and specific leaf area were higher in Nr, indicating that ethylene would exert a negative role in leaf growth and expansion under flooded conditions. Although stomatal conductance was hampered in flooded Nr plants, carboxylation activity was not affected by flooding in the mutant, suggesting that ethylene is responsible for inducing non-stomatal limitations to photosynthetic CO2 uptake. Upregulation of several cysteine protease genes and high protease activity led to Rubisco protein loss in response to ethylene under flooding. Reduction of Rubisco content would, at least in part, account for the reduction of its carboxylation efficiency in response to ethylene in flooded plants. Therefore, besides its role as a trigger of many adaptive responses, perception of ethylene entails limitations in light and dark photosynthetic reactions by speeding up senescence process that leads to a progressive disassembly of the photosynthetic machinery in leaves of flooded tomato plants. This article is protected by copyright. All rights reserved.

中文翻译：

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在乙烯敏感性降低的淹水番茄植株中维持光合能力

乙烯被认为是协调植物对洪水胁迫反应的最重要的植物激素之一。然而，乙烯可能会对植物产生有害影响，尤其是在响应胁迫以高速率产生时。在本文中，我们探讨了永不成熟 (Nr) 突变体中乙烯敏感性减弱对淹水番茄植株叶片光合能力的影响。我们发现 Nr 植物中乙烯感知的降低与更有效的光化学和非光化学辐射能量耗散能力有关，以应对洪水。数据与水淹 Nr 叶片中叶绿素和类胡萝卜素含量的保留相关。此外，Nr 的叶面积和比叶面积较高，表明乙烯在淹水条件下会对叶片的生长和扩张产生负面作用。尽管水淹 Nr 植物的气孔导度受到阻碍，但突变体中的水淹不会影响羧化活性，这表明乙烯是导致光合 CO2 吸收的非气孔限制的原因。几个半胱氨酸蛋白酶基因的上调和高蛋白酶活性导致 Rubisco 蛋白质在洪水下响应乙烯而丢失。Rubisco 含量的减少将至少部分地解释其羧化效率的降低以响应淹没设备中的乙烯。因此，除了作为许多适应性反应的触发器之外，对乙烯的感知还通过加速衰老过程导致光合作用机器的逐步分解，从而限制了明暗光合反应。本文受版权保护。版权所有。