为探究草酸对杏果实采后黑斑病的控制效果，该试验以“赛买提”杏为试材，采用2、4、6 mmol/L草酸对杏果实进行减压渗透处理，晾干后，置于温度和湿度为（1±1.0）℃、90%~95%的条件下，贮藏48 h后，损伤接种交孢链格孢（Alternaria alternata，A. alternata）并在相同条件下贮藏。定期测定苯丙烷代谢相关指标，孢子萌发率、菌落直径。损伤接种试验结果表明，在第49天时，与对照组相比，4 mmol/L草酸处理组接种发病率与病斑直径分别低了16.94%、19.44%。4 mmol/L草酸处理组的苯丙氨酸解氨酶（PAL）、4-香豆酸辅酶A连接酶（4CL）、肉桂酸-4-羟化酶（C4H）活性是对照组的1.06、1.04、1.07倍，有效促进了总酚、类黄酮、木质素含量的积累；体外试验结果表明，4 mmol/L草酸对A. alternata孢子萌发和菌丝生长有明显抑制作用。结果表明草酸处理可通过诱导苯丙烷代谢途径来增强杏果实对黑斑病的抗性。

The inhibitory effects of oxalic acid on postharvest black spot disease in apricot fruit were investigated by subjecting “Saimaiti” apricot fruit to pressure retarded osmosis using three different concentrations of oxalic acid (2, 4, and 6 mmol/L). Subsequently, the dried fruit were stored for 48 h at a temperature of (1±1.0) ℃ and a humidity of 90%~95%. Next, damaged fruit were inoculated with Alternaria alternata, and were stored under the same conditions described above. Indices related to phenylpropane metabolism, including spore germination rate and colony diameter, were regularly measured. The inoculation test results demonstrated that, on the 49th day, the incidence rate and lesion diameter of the 4 mmol/L oxalic acid-treated inoculated fruit were 16.94% and 19.44% lower, respectively, than those of the control group. Meanwhile, the activities of phenylalanine ammonia-lyase, 4-coumaric acid coenzyme-A-ligase, and cinnamate-4-hydroxylase in the 4 mmol/L oxalic acid-treated inoculated fruit were 1.06, 1.04, and 1.07 times, respectively, those of the control group. These results indicate that oxalic acid can effectively enhance the accumulation of total phenols, flavonoids, and lignin. Briefly, the in vitro experiments demonstrate that 4 mmol/L oxalic acid has considerable inhibitory effects on spore germination and mycelial growth of A. alternata. Thus, the application of oxalic acid treatments can enhance the resistance of apricot fruit to black spot diseases through the phenylpropane metabolic pathway.

国家自然科学基金地区科学基金项目（31860462）；南京农业大学-新疆农业大学联合基金项目（KYYJ201908）