Studies On Growth-promoting Effect Of Endophytic Fungi Of Wild Rice On Rice And Tobacco Seedlings

Endophytic fungi as a novel microbial resource, with the biological functions to enhance plant resistance to diseases and insects and promote the absorption of N, P etc nutrition elements, attracted the universal attention at home and abroad. Rice is one of the major food crops of human beings, studies on biological functions of rice endophytic fungi have been gradually carried out currently.This paper is focused on study of effect on the growth promotion of cultivated rice and tobacco by endophytic fungi from rare endangered wild rice. The results are as follows:(1) The effect on rice seedling growth by endophytic fungi was tested through co-culture between endophytic fungi and rice sterile seedling on1/2MS medium. The results showed that, of the tested107endophytic fungal strains from wild rice roots,13endophytic fungal strains (about12%) has a promoting effect on rice growth,86endophytic fungal strains (about80%) was neutral in the interaction effects of rice growth. In addition there are eight strains (about7%) inhibit rice growth. Of the tested48endophytic fungal strains from wild rice stems,44strains (about92%) showed strong pathogenicity, representing short, yellowing, thin stems, short root hairs, and sparse lateral roots, only four strains (about8%) without apparent inhibition on rice, showed neutral or slightly inhibited.(2)13wild rice endophytic fungal strains, with promoting effect on rice, screened further with Solanaceae plant tobacco by co-culture. The results showed that, Harpophora oryzae strain R5-6-1and RC3-1and Xylaria strain RK1-1had various level of promoting effects on tobacco, other9endophytic fungi without apparent growth-promoting effect on tobacco, while strain R4-4-1significantly inhibited the growth of tobacco. It proved that some endophytic fungi with specificity to plant host, but some endophytic fungi might be a wider host range.(3) In the co-culture system, Xylaria strain RK1-1showed apparent promoting effect on tobacco. Tobacco seedlings inoculated with RK1-1showed bigger and thicker leaves, stronger root system, and significantly increased shoot fresh weight and dry weight compared to control, but had the same numbers of leaves as treatments. The growth promotion effect stimulated by strain RK1-1was different from the reported effect of other fungal endophytes, thus the mechanism of growth-promoting effect needs further study.(4) Growth-promoting effect on tobacco stimulated by H. oryzae strain R5-6-1was verified further thought pot experiment. The results showed that strain R5-6-1had promoting effect to a certain extent, thus it has some potential application.