Abstract:

This article studied the response characteristics of protective enzymes and malondialdehyde (MDA) at the early stage of the development of arbuscular mycorrhizal between AM fungi and Amorpha fruticosa with a potting experiment in a greenhouse. The result showed that at the early stage of A. fruticosa infected with AM fungi, protective enzymes (PPO and POD) of the root system were transiently activated, along with an accumulation of flavonoid (a kind of phytoalexin). The activities of protective enzymes and the flavonoid contents had greater increases in roots inoculated with GI (Glomus intraradices) than GM (Glomus mosseae). Additionally, the contents of MDA decreased respectively 26.6% and 25.8% in GM- and GI- colonized plants in 25 d after the seed germination. With inactivation of the protective enzymes, contents of soluble protein and GlcN(Glucosamine) increased and some new proteins occurred, which indicated that the degradation of chitin and emergence of new proteins were potential mechanisms regulating the defense responses of host plants to develop mutually beneficial symbiosis.

Key words: arbuscular mycorrhizal fungi, malondiadehyde, flavonoid, glucosamin