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以苹果树腐烂病菌LXS080601、感病苹果品种‘富士’和抗病砧木‘平邑甜茶’愈伤组织为材料,测定腐烂病菌侵染后,愈伤组织内过氧化物酶(POD)、多酚氧化酶(PPO)、超氧化物歧化酶(SOD)和苯丙氨酸解氨酶(PAL)活性及丙二醛(MDA)含量的动态变化。结果显示,接种LXS080601后,‘富士’愈伤组织的发病严重度和病情指数均明显大于‘平邑甜茶’;感病品种MDA含量上升速度快,于接种后3 d增幅为28.02%,且变幅较大,为–0.32%~36.39%,而抗病砧木MDA含量变化较小,仅为–2.17%~7.46%。同时,腐烂病菌侵染提高了愈伤组织内4种防御酶活性,接种后1~2 d,PPO和POD酶活性达到高峰,接种后3~4 d,PAL和SOD酶到达活性高峰;除PPO外,‘平邑甜茶’PAL、SOD和POD酶活性变化均明显高于‘富士’,且整个侵染过程酶活性维持在较高水平,而‘富士’体内3种酶活性快速下降至对照水平,表明‘平邑甜茶’通过提高抗氧化酶活性减少体内活性氧的积累,降低膜脂过氧化产物MDA的形成,增强了对腐烂病菌侵染的抗性。
The effects of pathogen infection on the peroxidase (POD), polyphenols (POD) contents in callus were determined by using the apple tree rot fungus LXS080601, the susceptible apple cultivar ’Fuji’ and the disease resistant rootstock ’ (PPO), superoxide dismutase (SOD) and phenylalanine ammonia lyase (PAL) activity and malondialdehyde (MDA) content. The results showed that the disease severity and disease index of ’Fuji’ callus were significantly greater than that of ’Pingyi sweet tea’ after inoculation with LXS080601. The content of MDA in susceptible varieties increased rapidly by 28.02% after 3 days of inoculation, The amplitude of MDA was -0.32% ~ 36.39%, while the content of MDA in resistant rootstock changed little, only -2.17% ~ 7.46%. At the same time, the activity of four defense enzymes in callus was increased by rot pathogen inoculation. The activity of PPO and POD peaked at 1 ~ 2 d after inoculation, and reached the peak at 3 ~ 4 d after inoculation. Except PPO In addition, the activity of PAL, SOD and POD in ’Pingyi Sweet Tea’ was significantly higher than that in ’Fuji’, and the enzyme activity was maintained at a high level during the whole process of infection, while the activity of three enzymes in Fuji ’ , Indicating that ’Pingyi sweet tea’ can reduce the accumulation of reactive oxygen species in vivo by increasing the activity of antioxidant enzymes, reduce the formation of membrane lipid peroxidation product MDA and enhance the resistance to rot bacteria infection.