Zhou Rong, Niu Lifei, Yin Jian, Jiang Fangling, Wang Yinlei, Zhao Tongmin, Wu Zhen, Zhu Weimin
College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China.
Department of Food Science, Aarhus University, Agro Food Park 48, 8200 Aarhus N, Denmark.
Antioxidants (Basel). 2023 Jun 2;12(6):1205. doi: 10.3390/antiox12061205.
Waterlogging and heavy mental (e.g., cadmium) stress are two primary threats to crop growth. The combination of abiotic stresses was common and frequent, especially in the field condition. Even though the effects of individual waterlogging and cadmium on tomato plants have been widely investigated, the response of tomatoes under combined waterlogging and cadmium stress remains unclear. This study aimed to clarify and compare physiological, biochemical characteristics and plant growth of two tomato genotypes under individual and combined stress. Two tomato genotypes ('MIX-002' and 'LA4440') were treated under control, waterlogging, cadmium stress and their combination. The results showed that chloroplast ultrastructure of tomatoes under individual and combined stress was damaged with disordered stroma and grana lamellae. The HO (hydrogen peroxide) content and O (superoxide anion radical) production rate of plants under all the three stresses was not significantly higher than the control except for 'LA4440' under the combined stress. Antioxidant enzymes actively responded in the two tomato genotypes, as shown by significant increase in SOD activity from 'MIX-002' under waterlogging and combined stress and from 'LA4440' under cadmium. Meanwhile, CAT activity of 'MIX-002' under waterlogging and 'LA4440' under combined stress significantly decreased, and the POD activity of 'MIX-002' under combined stress significantly increased as compared with the respective control. The APX activity of 'MIX-002' and 'LA4440' under combined stress was significantly lower and higher than the respective controls. This indicated that tomato plants were able to secure redox homeostasis and protect plants from oxidative damage through the synergetic regulation of antioxidant enzymes. Plant height and biomass of the two genotypes under individual and combined stress significantly decreased, which could be a direct result from the chloroplast alteration and resource re-allocation. Overall, the effects of combined waterlogging and cadmium stress were not simply the sum of individual effects on two tomato genotypes. Distinct ROS (reactive oxygen species) scavenging systems of two tomato genotypes under stresses suggest a genotype-dependent antioxidant enzymes regulation.
涝害和重金属（如镉）胁迫是作物生长的两大主要威胁。非生物胁迫的组合常见且频繁，尤其是在田间条件下。尽管已广泛研究了涝害和镉对番茄植株的单独影响，但番茄在涝害和镉胁迫组合下的反应仍不清楚。本研究旨在阐明和比较两种番茄基因型在单独胁迫和组合胁迫下的生理、生化特性及植株生长情况。两种番茄基因型（‘MIX - 002’和‘LA4440’）分别在对照、涝害、镉胁迫及其组合条件下进行处理。结果表明，单独胁迫和组合胁迫下番茄的叶绿体超微结构受损，基质和类囊体片层紊乱。除组合胁迫下的‘LA4440’外，三种胁迫下植株的过氧化氢（HO）含量和超氧阴离子自由基（O）产生速率均未显著高于对照。两种番茄基因型中的抗氧化酶均有积极响应，如涝害和组合胁迫下‘MIX - 002’的超氧化物歧化酶（SOD）活性显著增加，镉胁迫下‘LA4440’的SOD活性显著增加。同时，涝害下‘MIX - 002’和组合胁迫下‘LA4440’的过氧化氢酶（CAT）活性显著降低，组合胁迫下‘MIX - 002’的过氧化物酶（POD）活性与各自对照相比显著增加。组合胁迫下‘MIX - 002’和‘LA4440’的抗坏血酸过氧化物酶（APX）活性分别显著低于和高于各自对照。这表明番茄植株能够通过抗氧化酶的协同调节维持氧化还原稳态并保护植株免受氧化损伤。单独胁迫和组合胁迫下两种基因型植株的株高和生物量显著降低，这可能是叶绿体改变和资源重新分配的直接结果。总体而言，涝害和镉胁迫组合的影响并非简单地是两种番茄基因型单独影响的总和。两种番茄基因型在胁迫下不同的活性氧（ROS）清除系统表明存在基因型依赖的抗氧化酶调节。
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