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.
J Agric Food Chem. 2023 Jun 21;71(24):9280-9290. doi: 10.1021/acs.jafc.3c00630. Epub 2023 Jun 8.
Chinese flowering cabbage is prone to senescence and yellowing after harvest, leading to a huge postharvest loss. Nitric oxide (NO) is a multifunctional plant growth regulator, but the effect of preharvest application of NO on the storage quality of Chinese flowering cabbage remains unclear. Preharvest application of 50 mg L sodium nitroprusside (SNP, a NO donor) to the roots obviously reduced leaf yellowing in Chinese flowering cabbage during storage. Proteomic analysis reveals 198 differentially expressed proteins (DEPs) in SNP-treated plants compared to the control. The main DEPs were significantly enriched in chlorophyll metabolisms, phenylpropanoid synthesis, and antioxidant pathways. SNP treatment enhanced chlorophyll biosynthesis and suppressed chlorophyll-degradation-related proteins and genes. It also modulated flavonoid-biosynthesis-related genes, and 21 significantly regulated flavonoids were identified in SNP-treated plants. The enhanced antioxidant capacity in SNP-treated plants was able to decrease chlorophyll catabolism by inhibiting peroxidase-mediated chlorophyll bleaching. Collectively, preharvest SNP treatment modulated chlorophyll metabolism and preserved chlorophyll content in leaves during storage. Moreover, SNP treatment enhanced flavonoid synthesis, suppressed reactive oxygen species accumulation, and delayed the senescence process, thereby maintaining leaf greening in Chinese flowering cabbage. These findings highlight the role of exogenous NO in alleviating yellowing of leafy vegetables.
菜花在收获后容易衰老和变黄，导致巨大的产后损失。一氧化氮（NO）是一种多功能的植物生长调节剂，但NO 对菜花贮藏品质的预采前应用效果尚不清楚。将 50mg/L 的硝普钠（SNP，NO 供体）施用于根部，可明显减少菜花在贮藏过程中的叶片黄化。蛋白质组学分析表明，与对照相比，SNP 处理的植物中有 198 个差异表达蛋白（DEPs）。主要 DEPs 在叶绿素代谢、苯丙烷合成和抗氧化途径中显著富集。SNP 处理增强了叶绿素的生物合成，抑制了叶绿素降解相关蛋白和基因。它还调节类黄酮生物合成相关基因，在 SNP 处理的植物中鉴定出 21 种显著调控的类黄酮。SNP 处理增强的抗氧化能力通过抑制过氧化物酶介导的叶绿素漂白来减少叶绿素的分解代谢。总之，预采前 SNP 处理调节了叶绿素代谢，在贮藏过程中保持了叶片中的叶绿素含量。此外，SNP 处理增强了类黄酮的合成，抑制了活性氧的积累，延缓了衰老过程，从而保持了菜花叶片的绿色。这些发现强调了外源 NO 在缓解叶菜类蔬菜黄化中的作用。
