番茄‘Ls-89’和‘坂砧2号’幼苗活性氧代谢对南方根结线虫侵染的反应

Reactive Oxygen Metabolism and Response to Meloidogyne incognita Infection in Tomato ‘Ls-89’ and ‘Banzhen 2’ Rootstock Seedlings

摘要:

为了解番茄(Lycopersicon esculentum)砧木幼苗活性氧代谢与抗南方根结线虫(Meloidogyne incognita)的关系,以高感品种‘Ls-89’与高抗品种‘坂砧2号’为材料,采用盆栽人工接种法,研究了南方根结线虫侵染对番茄砧木幼苗活性氧代谢的影响。结果表明,未接种南方根结线虫的番茄砧木幼苗,其根系与叶片活性氧水平及相关酶活性在品种间没有显著差异。接种南方根结线虫后,两品种幼苗根系与叶片的O₂·^- 生成速率和H₂O₂含量均升高,且‘坂砧2号’显著高于‘Ls-89’,但‘Ls-89’的MDA含量则显著高于‘坂砧2号’。两品种幼苗根系与叶片的SOD活性均在侵染早期降低,以‘坂砧2号’降幅较大;但POD、CAT活性在侵染早期变化不大,至侵染中后期则显著升高。因此,番茄抗性品种砧木幼苗的膜脂抗氧化能力较强,活性氧水平较高,且SOD活性对南方根结线虫侵染敏感。

Abstract:

In order to understand the relation between reactive oxygen (ROS) metabolism of tomato (Lycopersicon esculentum) rootstock seedlings and their resistance to Meloidogyne incognita, a high sensitive rootstock ‘Ls-89’ and a high resistant rootstock ‘Banzhen 2’ were planted in pots and inoculated with M. incognita, the effect of M. incognita infection on ROS metabolism and related enzyme activities in tomato rootstock seedlings was studied. The results showed that ROS level and related enzyme activities in roots and leaves had no significant difference between two varieties uninfected by M. incognita. After inoculated by M. incognita, both O₂·^- generation rate and H₂O₂ content in roots and leaves of two varieties increased, and those in ‘Banzhen 2’ were significantly higher than those in ‘Ls-89’, while MDA content in ‘Ls-89’ was significantly higher than that in ‘Banzhen 2’. At the early stage of infection, SOD activity decreased in roots and leaves of both varieties, and the decline in ‘Banzhen 2’ was bigger than that in ‘Ls-89’. The POD and CAT activities changed hardly at early stage of infection, and then significantly enhanced in middle and late infection stage. Therefore, the resistant rootstock seedlings had strong lipid antioxidant ability and high ROS level, and SOD activity in tomato rootstock seedlings was sensitive to the infection of M. incognita.