The Effects Of Inoculation Arbuscular Mycorrhizal Fungi On Growth And Fe Absorption Of Myrica Rubra Seedlings

Myrica rubra, which belongs to genus Myrica Linn in family Myricaceae, is an important subtropical specialty fruit tree in southern China.There are28species of genus Myrica Linn which perform the function of symbiotic nitrogen fixation with Frankia, can be grown in a harsh natural environment and play a role of conserving soil and water、reducing soil erosion and improving soil in all35species of genus Myrica Linn. It have been aroused many scholars’ interests to study the symbiotic association of plants、mycorrhizal fungi and nitrogen fixing bacteria since then Frank first discovered endotrophic mycorrhiza in the legumes and alder in1891.Arbuscular mycorrhizal fungi is a kind of endotrophic mycorrhiza fungi,which can forms mycorrhiza symbiosis by means of infecting the plant roots. According to statistics, about90%of the planet’s vascular plants can form arbuscular mycorrhizae. A great deal of researches reveal that AMF inoculation can not only promote plant growth, improve the plant mineral nutrition and water metabolism, but also improve photosynthetic capacity and resistance of plants. The growth of plant is effectively enhanced in view of the above reasons.Myrica rubra which roots and Frankia can form root nodule by means of symbiosis is considered to be fertilizers wood. Root nodule can promote the absorption and transformation of nitrogen and enhance the nitrogen-fixing ability of plants. Reported that root nodule became a symbiotic counterpart with Frankia and AMF and they could form a trisymbiosis. Efficiency of inoculation with AMF to Myrica rubra has not been reported especially the influence to nitrogen fixation. Iron is closely related with the formation of chlorophyll and is an important component of the iron redoxin, plant hemoglobin and nitrogenase. It is an important element in the system of mycorrhizal symbiosis-nitrogen fixation and directly involved in the physiological and biochemical processes of nitrogen fixation about the nitrogen-fixing plants. Therefore, the study about the suitable iron concentration range of Myrica rubra is important to promote the synthesis of the Myrica rubra chlorophyll and enhance the photosynthesis and nitrogen-fixing ability. In the present study, the growth status and the ability of nitrogen fixation of seedlings were studied by means of two AMF (Glomus versiforme, Glomus mosseae)which were inoculated to roots of Myrica rubra seedlings and with non-mycorrhizal plants as reference substance. This was done to select the excellent strain which is beneficial to growth and nitrogen fixation ability of Myrica rubra seedlings. It initially explored the appropriate iron concentration of Myrica rubra by5different iron levels of seedlings which were treated with. This paper can not only provide basic data for strong seedlings cultivation、high yield and quality cultivation of Myrica rubra in southern China, but also establish the theoretical foundation for further study of the interaction as well as promotion mechanism between AMF and Frankia. The results are as follows:1The two AMF could infect roots of Myrica rubra seedlings to form mycorrhizal symbionts, but the affinity between varieties of AMF and Myrica rubra was different. In this research, the affinity was better by inoculation of Glomus versiforme to Myrica rubra seedlings than G.m, and the infection rate achieved72.332±0.708%.2This paper confirmed that Myrica rubra could be effective infection with AMF(Gv and G.m) and form trisymbiosis of mycorrhiza-Myrica rubra-Frankia when it already has the symbiotic Frankia. Moreover AMF inoculation could delay root nodules’ senescence, promote the absorption of N and enhance the nitrogen fixation capacity of Myrica rubra.3The results show that AMF inoculation could promote plant growth, improve the plant mineral nutrition, improve photosynthetic capacity and resistance of Myrica rubra seedlings. The growth of plant was effectively enhanced in view of the above reasons. But the effect was not significant for nodules’ development. In this study, the promotion was better by inoculation of Glomus versiforme to Myrica rubra seedlings than G.m.4Based on the same inoculation conditions, the research showed that the content of Fe increased with the improving of iron level, but Ci and soluble sugar content showed the trend from decrease to increase,the content of N/P/K、seedlings height、shoot base diameter、fresh mass、chlorophyll、Pn、Gs、Tr、leaf water content and soluble protein content showed the trend from increase to decrease with the improving of iron level. It was confirmed that iron levels had various effects on the growth of Myrica rubra seedlings. The iron level for50mg/L was suitable in this study. The correlation test showed that iron levels had significant influence to the mineral nutrition and photosynthesis of Myrica rubra seedlings.