In order to clarify the effect of AMF on the resistance of muskmelon to compound stress,and to explore its physiological mechanism,we investigated the effects of arbuscular mycorrhizal fungi (AMF) on the growth and the antioxidant activities of melon under low light and salt stress by pot experiment in greenhouse.The results showed that:(1) the growth of melon seedlings was significantly inhibited.The plant height,the dry weight and the fresh weight were significantly reduced.Soluble protein,soluble sugar,proline,malondialdehyde (MDA) contents and antioxidant enzymes activities (SOD,POD and CAT) in melon seedlings under low light and salt stress were higher than those in control group.(2) The inoculation with Glomus could significantly promote the growth of muskmelon seedlings,and the rate of mycorrhizal infection was negatively correlated with salt stress with the extension of stress time.(3) The inoculation with Glomus improves the physiological parameters of inoculated seedlings compared with non-AM seedlings;the contents of soluble sugar,soluble protein,starch,proline and antioxidant enzymes activities (SOD,POD and CAT) increased significantly,while MDA content decreased,and mycorrhizal infection rate with stress duration was negatively correlated with the salt concentration;the contents of SOD and POD in leaves were more active than those in roots,while CAT activity was less than that in roots.We propose that AM symbiosis can protect melon plants from low light and salt stress hy improving their antioxidant activities and bi-directional transport of carbohydrates.%以甜瓜(Cucumis melo L.)品种“中蜜3号”为试材,摩西球囊霉菌(Glmous mosseae,GM)为供试菌种,采用温室盆栽试验研究接种丛枝菌根真菌(AMF)对弱光及盐胁迫下甜瓜生长和抗氧化酶活性的影响,以明确AMF对甜瓜复合逆境下的增抗作用并探讨其生理机制.结果显示:(1)在弱光及盐胁迫条件下,甜瓜幼苗生长受到明显抑制,其株高、干重和鲜重均明显降低,同时体内可溶性糖、可溶性蛋白、脯氨酸和MDA含量以及SOD、POD、CAT活性均比对照显著升高.(2)弱光及盐胁迫下,接种AMF可显著促进甜瓜幼苗的生长,菌根侵染率随胁迫时间延长与盐浓度呈负相关关系.(3)弱光及盐胁迫下,接种AMF进一步提高了甜瓜幼苗体内可溶性糖、可溶性蛋白、淀粉和脯氨酸含量及SOD、POD、CAT活性,显著降低了MDA含量,且叶片SOD、POD活性变化大于根系,CAT则相反.研究表明,AMF可通过促进弱光及盐胁迫下甜瓜生长和抗氧化酶活性的提高,有效降低体内膜脂过氧化水平,从而增强植株对弱光及盐胁迫的耐性.
展开▼
