Black spot disease, caused by the fungal pathogen Alternaria alternata, commonly infects apple (Malus domestica) during postharvest storage and transportation, diminishing fruit quality, contaminating the fruit with toxins, and causing significant economic losses. Here, we investigated the effect of 0.1 mmol L⁻¹ sodium nitroprusside (SNP), a nitric oxide donor, on lesion diameter, fruit quality, and reactive oxygen species (ROS) metabolism in A. alternata-inoculated apples. SNP not only effectively decreased lesion diameter but also maintained fruit quality and cell membrane integrity. Additionally, SNP enhanced antioxidant enzyme activity and genes encoding of peroxidase (POD), glutathione reductase (GR), superoxide dismutase (SOD), ascorbate peroxidase (APX), and catalase (CAT), and decreased hydrogen peroxide (H₂O₂) and superoxide anion (O₂^•−) production, malondialdehyde (MDA) concentration, and membrane permeability. Collectively, these results demonstrate that SNP inhibits ROS accumulation and increases antioxidant enzyme activity, and that the mechanism of SNP-induced resistance is related to the regulation of ROS metabolism.

黑斑病是由真菌病原菌链格孢( Alternaria alternata )引起的，通常在采后储存和运输过程中感染苹果( Malus Domestica )，降低果实品质，使果实受到毒素污染，造成重大经济损失。^{在这里，我们研究了0.1 mmol L -1}硝普钠（SNP）（一种一氧化氮供体）对接种链格孢的苹果病斑直径、果实品质和活性氧（ROS）代谢的影响。SNP不仅能有效减小病斑直径，还能保持果实品质和细胞膜完整性。此外，SNP 增强了抗氧化酶活性以及编码过氧化物酶 (POD)、谷胱甘肽还原酶 (GR)、超氧化物歧化酶 (SOD)、抗坏血酸过氧化物酶 (APX) 和过氧化氢酶 (CAT) 的基因，并减少过氧化氢 (H ₂ O ₂ )以及超氧阴离子 (O ₂ ^•− ) 产生、丙二醛 (MDA) 浓度和膜渗透性。总的来说，这些结果表明SNP抑制ROS积累并增加抗氧化酶活性，并且SNP诱导的抗性机制与ROS代谢的调节有关。