Gan Linzhi, Mou Zhenliang, Chen Jianye, Shan Wei, Kuang Jianfei, Lu Wangjin, Zhao Yating, Wei Wei
State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources/Guangdong Provincial Key Laboratory of Postharvest Science of Fruits and Vegetables/Engineering Research Center of Southern Horticultural Products Preservation, Ministry of Education, College of Horticulture, South China Agricultural University, Guangzhou 510642, China.
College of Food Science and Pharmacy, Xinjiang Agricultural University, Urumqi 830052, China.
Foods. 2024 Dec 25;14(1):29. doi: 10.3390/foods14010029.
Leaf senescence is a major concern for postharvest leafy vegetables, as leaves are highly prone to yellowing and nutrient loss, resulting in reduced commercial value and limited shelf-life. This study aimed to investigate the effect of L-cysteine (L-cys) on postharvest Chinese flowering cabbage stored at 20 °C. The results showed that 0.5 g L L-cys treatment effectively slowed leaf senescence by downregulating chlorophyll degradation genes , , , , and ) and senescence marker gene . Moreover, this treatment exhibited positive influence on the nutritional quality of cabbage. Also, L-cys treatment maintained ROS homeostasis, preventing excessive ROS accumulation and lipid membrane oxidation. L-cys treatment also maintained a higher total antioxidant capacity and scavenging rate of •OH and O. Additionally, L-cys treatment maintained high levels of ascorbate and glutathione and activated antioxidant enzymes (superoxide dismutase, peroxidase, and catalase) and the expression of the encoding genes. Furthermore, L-cys treatment elevated endogenous HS levels, which are correlated with increased L-cysteine desulfhydrase activity and the upregulation of HS biosynthesis-related genes. These findings suggest that L-cys can delay leaf senescence by reducing chlorophyll breakdown, maintaining ROS homeostasis, and stimulating endogenous HS production.
叶片衰老对于采后叶菜类蔬菜来说是一个主要问题，因为叶片极易发黄和营养流失，从而导致商业价值降低和货架期缩短。本研究旨在探究L-半胱氨酸（L-cys）对采后在20℃储存的菜心的影响。结果表明，0.5 g/L L-cys处理通过下调叶绿素降解基因（ 、 、 、 和 ）以及衰老标记基因，有效延缓了叶片衰老。此外，该处理对白菜的营养品质表现出积极影响。而且，L-cys处理维持了活性氧（ROS）稳态，防止ROS过度积累和脂质膜氧化。L-cys处理还维持了较高的总抗氧化能力以及对•OH和O的清除率。另外，L-cys处理维持了高水平的抗坏血酸和谷胱甘肽，并激活了抗氧化酶（超氧化物歧化酶、过氧化物酶和过氧化氢酶）及其编码基因的表达。此外，L-cys处理提高了内源性硫化氢（HS）水平，这与L-半胱氨酸脱硫酶活性增加以及HS生物合成相关基因的上调有关。这些发现表明，L-cys可以通过减少叶绿素分解、维持ROS稳态和刺激内源性HS产生来延缓叶片衰老。
