PHOTOSYNTHETIC ACTIVITY OF TALL FESCUE AS INFLUENCED BY A FUNGAL ENDOPHYTE

A controlled environment study addressed the impact of endophyte (Acremonium coenophialum Morgan-Jones et Gams) upon the net photosynthetic rate (PN) and tiller production of genetically uniform tall fescue (Festuca arundinacea Schreb.). PN was modelled by the logistic growth equation for both infected and non-infected plants. Non-infected tall fescue plants achieved a significantly greater PN than infected plants in response to increasing irradiance. PN among the five clones in our study was not significantly different within a given endophyte status. Yields tended to be greater in infected than in non-infected plants of certain clones. Tiller production was significantly greater in four out of five infected compared to non-infected clones. The lower PN along with generally increased tiller production of infected plants may confer adaptive advantage over non-infected fescue plants or competing species in environment with limited water and nutrients.