| Mycorrhizae are symbiotic associations between plant roots and certain soil fungi and the almost plants can form the mycorrhiza structure in the natural condition. The arbuscular mycorrhiza (AM) is the commonest mycorrhizal association between host plant roots and seven genera of soil fungi (Arbuscular Mycorrhizal Fungi, AMF), which are classified to Eodogone , Glomus. Sclerocysfis. Acaulospora. Entrophospora. Gigaspora and Scutellospora. It was known that the AMF played a key role in nutrient cycling in the ecosystem and promoting plant growth and also protected host plants against environmental stress. Due to the positive effects of AMF, the studies and utilization of AM biotechnology were being paid enormous attention, and great advance was achieved all over the world. In recent years, researchers have made some progress in stimulative substances for AMF growth and development and AMF in vitro culture, but AMF couldn't complete their life cycle in vitro. So, AMF inoculum used in commercial propagating plantlets or scientific researches are often host plant roots infected with AMF or rhizosphere soil with AMF, which brought many difficulties to the studies and utilization of AM biotechnology.With the two AMF (Glomus mosseae, Gigaspora margarita) being used as the main experimental materials, the experiments were carried out to study the effects of polyamine (PA) and methanol eluates fractionated from Ginkgo biloba root on the growth and development of AMF in vitro, the traits of AMF infection in grape (Vitis vinifera L.) root in vitro and the effects of PA on the growth and development of micropropagated grape plantlets as follows:Master Degree Dissertation, 2003 : Study on In vitro Culture of Arbuscular Mycorrhizal Fungi and TheirEffects on the Growth of Micropropagated Grape (Vitis vinifera L.)Experiment 1 Study on effects of PA on the growth and development of AMF in vitroPA are a sort of low molecular weight alkali with nitrogen element and have physiological activity. It can control the metabolism of nucleic acid and protein, promote cell differentiation and have important regulative effects on the plant growth by combined with deoxyribonucleic acid or ribonucleic acid. It was considered that PA was a kind of second messenger.hi experiment 1, the effects of PA (Putrescine, PUT; Spermine, SPM; Spermidium, SPD) and PA biosynthesis inhibitor (Methylglyoxal Bis (Guanylhydrazone), MGBG) on spore germination character and hyphal growth and development of AMF (Gl. mosseae, Gi. margarita) in vitro was studied. The results indicated that PUT, SPD and SPM had significant effects on spore germination rate and hyphal growth of AMF at the range of 50ug/ml~200ug/ml, but high concentration PA treatment (at 500ug/ml) indicated significantly inhibiting effect. From 50ug/ml to 500ug/ml, MGBG had negative effect on the growth and development of AMF and this effect could be partially relieved by exogenous application of PA, but this relief role was reduced when the concentration of MGBG increased. The author realized that the endogenous concentration of polyamine of AMF might be a limiting factor of the growth and development.The results showed that the effects of PA on the growth and development of AMF were dependent on the fungi species and the PA treatment concentration: the reaction of Gl. mosseae to PA was more sensitive than Gi. margarita^', the effect of PA was positive in low concentration, but it changed into negative in high concentration. In generally, it was known that the more -NHa PA had, the more distinct physiological activity PA had. So, SPM had the most distinct activity, SPD had the secondly high activity and activity of PUT was vague, which coincided with the results obtained from this experiment.Experiment 2 Study on the effects of methanol eluates fractionated from Ginkgo biloba root on the growth and development of AMF in vitroSome researches have showed that eluates of plant root had some effects on the growth and development of AMF, at same time, the flavonoids of... |
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