ABSTRACT Tomato (Solanum lycopersicum L.) fruit cracking is a serious economic problem, affecting fruit quality and yield. During abiotic stress, the imbalance of reactive oxygen species (ROS) metabolism causing membrane damage might increase the susceptibility of pericarp to changing environment and then affect fruit cracking. To further validate the relationship between ROS metabolism and fruit cracking, we used cracking-resistant tomato ‘LA1698’ and cracking-susceptible tomato ‘LA2683’ as test materials. ROS, membrane lipid peroxidation, antioxidants and soluble protein in different parts (top, middle and bottom) of epicarp and mesocarp were studied. Results showed that, the highest ROS levels and membrane lipid peroxidation degree were observed in the top of epicarp in ‘LA2683’. Moreover, ‘LA2683’ displayed lower superoxide dismutase (SOD), ascorbate peroxidase (APX), glutathione reductase (GR) activity and ascorbic acid (AsA) content, and maintained higher polyphenol oxidase (PPO), peroxidase (POD), catalase (CAT) activity and soluble protein content in each part of epicarp, compared with ‘LA1698’. In conclusion, the top of epicarp in ‘LA2683’ accumulated higher ROS, concurrent with decreased ROS scavenging ability, and the disordered ROS homoeostasis led to cellular oxidative damage, which could effect the occurrence of cracking at the top of fruit. ROS metabolism in epicarp may play an important role in fruit cracking.

中文翻译：

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外果皮和中果皮上部、中部和下部活性氧代谢差异对番茄果实开裂的影响

摘要 番茄（Solanum lycopersicum L.）裂果是一个严重的经济问题，影响果实品质和产量。在非生物胁迫期间，活性氧（ROS）代谢失衡导致膜损伤可能会增加果皮对环境变化的敏感性，进而影响果实开裂。为了进一步验证ROS代谢与果实开裂之间的关系，我们使用抗开裂番茄'LA1698'和易开裂番茄'LA2683'作为试验材料。研究了外果皮和中果皮不同部位（顶部、中部和底部）的活性氧、膜脂过氧化、抗氧化剂和可溶性蛋白。结果表明，'LA2683'在外果皮顶部观察到最高的ROS水平和膜脂过氧化程度。此外，“LA2683”显示出较低的超氧化物歧化酶 (SOD)，外果皮各部位抗坏血酸过氧化物酶（APX）、谷胱甘肽还原酶（GR）活性和抗坏血酸（AsA）含量，并保持较高的多酚氧化酶（PPO）、过氧化物酶（POD）、过氧化氢酶（CAT）活性和可溶性蛋白含量。与'LA1698'。综上所述，'LA2683'的外果皮顶部积累了较高的ROS，同时清除ROS的能力下降，ROS稳态失调导致细胞氧化损伤，从而影响果实顶部开裂的发生。外果皮中的 ROS 代谢可能在果实开裂中起重要作用。综上所述，'LA2683'的外果皮顶部积累了较高的ROS，同时清除ROS的能力下降，ROS稳态失调导致细胞氧化损伤，从而影响果实顶部开裂的发生。外果皮中的 ROS 代谢可能在果实开裂中起重要作用。综上所述，'LA2683'的外果皮顶部积累了较高的ROS，同时清除ROS的能力下降，ROS稳态失调导致细胞氧化损伤，从而影响果实顶部开裂的发生。外果皮中的 ROS 代谢可能在果实开裂中起重要作用。