不同传播方式的内生真菌感染对羽茅的生理生态影响北大核心CSCD

通过田间试验,研究了垂直传播的Neotyphodium属内生真菌和水平传播的Epichloё属内生真菌对羽茅(Achnatherum sibiricum)生理生态的影响。结果表明:Neotyphodium属内生真菌感染对羽茅的株高和叶长有显著的正效应,而Epichloё属内生真菌感染对羽茅株高和叶长的增益作用较少。感染Neotyphodium属内生真菌的羽茅最大净光合速率显著高于感染Epichloё属内生真菌的羽茅,Neotyphodium属内生真菌显著提升了羽茅的气孔限制值和水分利用效率,而实验测定的第一年结果显示:Epichloё属内生真菌对羽茅的各个光合指标具有明显的负效应(胞间CO2浓度除外)。Neotyphodium属内生真菌感染使得宿主植物积累的可溶性糖含量显著高于感染Epichloё属内生真菌的羽茅和不染菌的羽茅植株。感染Epichloё属内生真菌的羽茅中氮含量显著高于感染Neotyphodium属内生真菌的羽茅。总之,内生真菌的传播方式是影响羽茅生理生态学特性的一个因素,并且垂直传播的内生真菌对羽茅生长和生理特性的益处高于水平传播的内生真菌。

Effects of endophyte transmission on ecophysiological characteristics of Achnatherum sibiricum

Aims Achnatherum sibiricum plants were infected by fungal endophytes Neotyphodium and Epichloë and high infection rates have been found in our experimental field. Our objective was to determine the effects of Neotyphodium and Epichloë 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 Epichloë.
Important findings Neotyphodium infection had a significant positive effect on both leaf length and plant height in A. sibiricum, whereas Epichloë 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 Epichloë; whilst Neotyphodium infected plants had significantly higher maximum net photosynthetic rate than Epichloë infected plants. Moreover, Neotyphodium infection significantly increased stomatal limitation and water use efficiency (WUE) of the host grass. Epichloë 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 Epichloë infection and endophyte-free treatment. The N% in Epichloë infected plant was significantly higher than in Neotyphodium infected plants in both years and in endophyte-free plants in the second year.