干旱胁迫下内生真菌感染对黑麦草实验种群光合、蒸腾和水分利用的影响

 以黑麦草(Lolium perenne L．)为实验材料，研究在不同强度的干旱胁迫下内生真菌(Neotyphodium lolii (原 Acremonium lolii))感染对其净同化速率、蒸腾速率和水分利用效率的影响。结果显示：1)在干旱胁迫前期，内生真菌感染(EI)种群和非感染(EF)种群之间的群体净同化速率无显著差异；到胁迫后期，在重度胁迫下EI种群的净同化速率高于EF种群；复水后，各个胁迫强度EI和EF种群的净同化速率均迅速恢复，差异消失；2)在群体蒸腾速率上，干旱胁迫对其影响大于内生真菌的影响；3)在群体水分利用效率上，只是在重度胁迫后期，EI种群才高于EF种群。

EFFECTS OF ENDOPHYTE INFECTION ON PHOTOSYNTHESIS, TRANSPIRATION AND WATER USE EFFICIENCY OF LOLIUM PERENNE L. UNDER DROUGHT STRESS

Net assimilation rate, transpiration rate and water use efficiency of endophyte-infected (EI) and endophyte-free (EF) populations of Lolium perenne were determined under drought stress so as to investigate the effect of endophyte infection on the host plant.The physiological characteristics of L.perenne populations depended much on drought stress levels,and the effects of endophyte infection were significant under prolonged severe stress.1) At the late stage of severe drought stress, the EI populations assimilated CO_2 at a significantly higher rate than the EF populations.After rewatering, however,there were no significant differences between the two populations 2)Transpiration rate of the populations was more affected by drought stress than endophyte infection.3) Only at the later stage of severe drought stress,was the water use efficiency of the EI populations higher than that of the EF populations.