BHT对苹果采后灰霉病的防效及防御酶活性和丙二醛含量的影响

为探究2,6-二叔丁基-4-甲基苯酚(2,6-di-tert-butyl-4-methylphenol,BHT)对苹果采后灰霉病的防效和防病机制,采用平板法和刺伤接种法测定了BHT对灰霉病菌Botrytis cinerea的抑制作用及果实内防御酶活性和丙二醛含量的影响。结果表明,0.1 mmol/L BHT对苹果灰霉病的防效最佳,处理苹果后间隔48～96 h接种灰霉病菌,其防效可达68.59%～73.55%,其次为0.2、1.0 mmol/L BHT处理,但防效均低于52.94%。0.1 mmol/L BHT处理对灰霉病菌菌丝生长和分生孢子萌发无显著抑制作用,但可显著增强果实内超氧化物歧化酶、过氧化物酶和过氧化氢酶的活性以及总抗氧化能力,其峰值是对照的1.82～5.28倍,且均显著高于单独接种灰霉病菌的处理。此外,单独接种灰霉病菌的苹果果实内丙二醛含量快速升高,最大增幅达251.49%,而BHT处理后丙二醛含量变幅较小,最大增幅仅为83.95%。表明BHT可通过增强苹果果实内防御酶活性水平和总抗氧化能力来降低丙二醛的积累,从而提高果实对灰霉病的抗性。

Control efficiency of BHT against postharvest apple grey mold and its influence on the activity of defensive enzymes and content of malondialdehyde

In order to explore the control efficiency and biocontrol mechanism of 2,6-di-tert-butyl-4- methylphenol (BHT) against postharvest apple grey mold caused by Botrytis cinerea, the inhibitory effect of BHT to B. cinerea, and its effect on the activity of defensive enzymes and the content of malondialdehyde (MDA) in apple fruits were determined by using the agar plate and the wound inoculation methods. The results showed that, when apple was treated with 0.1 mmol/L BHT for 48 to 96 h and then inoculated with B. cinerea, the control efficiency was the best and could reach 68.59% to 73.55%, followed by 0.2 mmol/L and 1.0 mmol/L BHT, but the control effects were less than 52.94%. 0.1 mmol/L BHT had no significant effect on conidial germination and mycelial growth of B. cinerea; however, BHT could significantly enhance the activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) as well as the total antioxidant capacity (T-AOC) in apple fruits. The peaks of defense enzyme activity and T-AOC in the fruit treated with BHT were 1.82 to 5.28 times higher than those of the controls, which were all significantly higher than that in the treatment with only the pathogen inoculation. In addition, MDA content increased rapidly and the maximum increase rate was up to 251.49% in the fruit inoculated with B. cinerea, but MDA content changed less in the fruit treated with BHT and the maximum increase rate was only 83.95%. The results suggested that BHT could induce apple fruit resistance against pathogen infection via increasing the activity of defensive enzymes and T-AOC and reducing the accumulation of MDA.