Effects of Organic Acids content in Roots and Root Exudates of Hordeum bogdanii by Endophytic Fungi

Organic acid is one of the important components in plant roots and root exudates, which plays an important role in nutrient activation, changing soil microbial activity and alleviating metal element toxicity stress. To study the effect of endophytic fungi infection on the organic acid contents of plants, this study used the grass species Hordeum bogdanii , Endophytic Fungi (E+) and without endophytic fungi (E-) H. bogdanii grasses from Wensu County, Xinjiang Province, China, as test materials H. bogdanii plants were grown hydroponically and treated with 0, 50 and 150 mmol/L mixed alkali (Na2CO3:NaHCO3 = 1:1) for 1 and 21 h. Root exudates and fresh root samples were collected for determination the organic acid contents of malic acid, shikimic acid, citric acid, and oxalic acid. The results showed that under alkali stress, the oxalic acid content in roots and root exudates of E + and E- plants decreased. The contents of citric acid and shikimic acid in roots and root exudates of E + and E- plants increased first and then decreased. Malic acid content in root exudates did not change significantly, and malic acid content in roots increased with the increase of alkali stress time. Among them, the organic acid content of H. bogdanii E + plants was significantly higher than that of uninfected E- plants, indicating that endophytic fungi under alkali stress were helpful to increase the root exudates of H. bogdanii grass and the accumulation of malic acid, shikimic acid, citric acid and oxalic acid content in the root. The most obvious change was oxalic acid content, and there was interaction between endophytic fungi and alkali treatment. It indicated that endophytic fungi could increase the secretion of organic acids from plants under alkali stress, which was conducive to the survival of plants in alkaline soil.