Effects of endophyte transmission on ecophysiological characteristics of Achnatherum sibiricum

Abstract

Aims Achnatherum sibiricum plants were infected by fungal endophytes Neotyphodium and Epichloe and high infection rates have been found in our experimental field. Our objective was to determine the effects of Neotyphodium and Epichloe on growth and physiological characteristics in A. sibiricum. Methods In a field experiment, we measured plant growth and physiological characteristics of A. sibiricum with a LI-6400 portable photosynthesis system and determined the contents of carbon (C%) and nitrogen (N%) and other physiological variables in 2011 and 2012. Achnatherum sibiricum plants were successfully infected with Neotyphodium and Epichloe. Important findings Neotyphodium infection had a significant positive effect on both leaf length and plant height in A. sibiricum, whereas Epichloe infection had a significant negative effect on the two variables. Maximum net photosynthetic rate was significantly higher in the endophyte-free plants than in plants infected by Neotyphodium and Epichloe; whilst Neotyphodium infected plants had significantly higher maximum net photosynthetic rate than Epichloe infected plants. Moreover, Neotyphodium infection significantly increased stomatal limitation and water use efficiency (WUE) of the host grass. Epichloe infection had a negative effect on photosynthetic variables except intercellular CO2 concentration in the first year. Neotyphodium infection resulted in greater accumulation of soluble sugars in host plants than Epichloe infection and endophyte-free treatment. The N% in Epichloe infected plant was significantly higher than in Neotyphodium infected plants in both years and in endophyte-free plants in the second year.