Study On Effects Of Arbuscular Mycorrhizal Fungi On The Growth And Drought Resistance Of Grape (Vitis Vinifera L.) Seedling

The grape is a kind of fruit with high value. In fruit products of world, its yield and acreage are maximal among others fruits variety. Grape seedlings are material foundation of grape-production. Cuttage and tissue culture technique are often adopted in nursery-stock cultivation at the moment. The seedlings propagated by these methods are influenced easily by environmental stress for their weak rootage, therefore growth and stress-resistance of seedlings is weak, survival percentage is low, yield and quality of fruit is effected. The almost plants can form the arbuscular mycorrhiza (AM) structure in the natural condition. The arbuscular mycorrhiza is a sort of beneficial symbiont between plant roots and seven genera of soil fungi (Arbuscular Mycorrhizal Fungi, AMF), which are classified to Eodogone, Glomus, Sclerocystis, Acaulospora, Entrophospora, Gigaspora and Scutellospora. It was known that the AMF could protect host plants against environmental stress and promote plant growth. Due to the positive effects of AMF, the studies and utilization of AM biotechnology were being paid enormous attention. So, if we can inoculate proper AMF in early stage of seedlings and produce seedlings with mycorrhiza structure, the transplant survival rate, growth potential, multiplication rate of grape seedlings would be greatly promoted.Drought is a global natural disaster, which seriously restrain the agricultural sustainable development. In our country, the majority of vineyards set up in arid or semi-arid region. Though grape is a drought enduring plant that has the adaptive ability to drought, it needs a lot of water for favorable growth. It was known that AM symbiont can resist drought stress of soil. So, utilization of AM biotechnology to improve drought resistance of plant had been paid attention. Studies ofAMF and plant water relation have been a focus of drought-stress resistance research in recent years, great advance was achieved, but mechanism of improving water metabolism of plants by AMF isn't very clear.Trying to solve the problem of utilization of AM biotechnology, the experiments were carried out to study effects of different AMF (Glomus mosseae, Gigaspora margarita) on transplantation of tissue-cultured plantlets of grape, effects of AMF on water metabolism of grape seedlings and mechanism of improving drought resistance of seedlings by AMF. The results are showed as follows:Experiment 1 Study on the effects of AMF on the growth and development of tissue-cultured plantlets of grape (Vitis vinifera L.)In recent years, there has been fast development of tissue culture technology of grape. Because of poor formation of AM in axenic condition, the tissue-cultured grape plantlets exhibited some limitation, including a very slow rate of growth during the weaning phase, weak growth potential, low transplant survival rate and resistance to environmental stress. Grape could be infected by some kinds of AMF and its healthy growth and development was dependent on well-developed AM structure in great degree. So, if we can inoculate proper AMF in early stage of seedlings, the transplant survival rate, growth potential, multiplication rate of grape seedlings would be greatly promoted. In this experiment, the effects of inoculation with AMF on the growth and acclimatization of tissue-cultured plantlets during ex vitro transfer were investigated. The results showed that AMF had important stimulative effects on tissue-cultured grape plantlets in ex vitro condition. The activity of phosphatase in tissue-cultured grape plantlets root was distinctly enhanced by AMF infection. Inoculation of the AMF when plantlets were transferred from in vitro conditions to ex vitro conditions improved the absorbency of root, shoot and root growth, increased the root/shoot ratio and the content of N, P in plant tissues, promoted photosynthesis, growth potential, the transplant survival rate, and helped plantlets to tolerate environmental stress at transplanting.Some researches have indicated that AMF and host plant have a little mutual selectivity, and different AMF have different infection rate in different host plants. In the experiment, the research also discovered that potential of AMF infection was higher and arriving steady infection period was eariler when grape plantlets infected with Gl. mosseae than infected with Gi. margarita. So, author thought that Gl. mosseae might be preponderant AMF strain of grape.