Effects of seed moisture content and Epichloe endophyte on germination and physiology of Achnatherum inebrians

Vertically transmitted Epichloe endophyte can be beneficial to host grasses. In order to achieve high seed and endophyte viability under storage, knowledge of optimal seed moisture content and germination behavior of endophyte-infected grass seed is required. In the current research project, Achnatherum inebrians seeds were adjusted to different moisture contents to investigate effects on germination and viability of the endophyte, E. gansuensis, after six months of storage. To explore mechanism of the effect of moisture content and endophyte on seed germination, a number of physiological and biochemical indicators were determined, including electrical conductivity (EC), contents of proline (Pro), malondialdehyde (MDA) and total soluble sugar; activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and hydrogen peroxide (H2O2). The results showed that the viability of the endophyte at 5.5% and 9.5% seed moisture was significantly (p<0.05) higher than with other seed moisture treatments. Furthermore, the infection rate was higher than the corresponding germination percentage at each seed moisture content. The endophyte significantly (p<0.05) improved the seed germination percentage, germination index, and vigor index at the seed moisture contents of 5.5% and 9.5%. A value of 5.5% was found to be the optimal seed moisture content under storage. This moisture level enhanced the activity of antioxidant enzymes and reduced lipid peroxidation of cell membranes, which is likely to be responsible for the slowing of which is likely to be responsible for the slow ing of the decline in viability of Achnatherum inebrians seeds. Compared to the seed with endophyte, uninfected seeds had lower soluble sugar and proline contents. We conclude that the presence of the endophyte can improve vigor of A. inebrians seed after prolonged storage at low and intermediate moisture levels. (c) 2020 SAAB. Published by Elsevier B.V. All rights reserved.