橘青霉侵染对杨梅果实酚类物质代谢作用的影响

以采前套袋控制病原菌潜伏侵染的杨梅果实为材料,采后接种橘青霉病菌,旨在研究橘青霉侵染对杨梅果实酚类物质含量及相关氧化酶活性变化的影响。结果表明:橘青霉侵染初期,杨梅果实细胞多酚氧化酶(PPO)、过氧化物酶(POD)活性呈上升趋势,酚类物质快速合成以提高自身的抗病能力。而同时期苯丙氨酸解氨酶(PAL)活性并没有相应增加,反而下降较快,致使木质素合成受阻,说明橘青霉侵染虽然诱导杨梅果实产生一定的抗病性,但这种抗病能力有限。贮藏中后期,虽然POD活性略有下降,PPO活性保持平稳,但二者始终处于较高水平,从而导致前期积累的酚类物质被大量降解,加上前期木质素合成受阻的影响,橘青霉更容易穿透杨梅果实细胞壁,进入细胞组织内繁殖生长,最终导致果实腐败。

EFFECT ON PHENOLIC METABOLISM IN CHINESE BAYBERRY FRUIT INFECTED BY PENICILLIUM CITRINUM

Using Chinese bayberry fruit bagged to control the latent infestation of pathogenic bacteria before harvest as the material, fruit after harvest were vaccinated by Penicillium citrinum, in order to study the effects on the phenolics content and the activities of some related oxidases. The results exhibited that the activities of PPO and POD in the fruit cells of bayberry increased, and phenolics were rapidly generated to improve their disease resistance on early stage of P. citrinum infection. At the same time, the PAL activity did not increase correspondingly, but decreased rapidly, resulting in lignin synthesis blocking. It indicated that the infection of P. citrinum induced certain disease resistance of the fruits, but it was limited. Although the activity of POD decreased slightly and the activity of PPO remained stable during the middle and late storage stages, they were both always at a high level, leading to the degradation of the phenolic substances accumulated in the early stage. Combined with the blocking of lignin synthesis in the early stage, P. citrinum could penetrate the cell wall and enter into the cell tissue to grow and reproduction, eventually lead to fruit spoilage.