AGRO-PHYSIOLOGICAL CHARACTERISTICS OF ENDOPHYTE-INFECTED PERENNIAL RYEGRASS (LOLIUM PERENNE L.)

L.C. Deleuran, R. Gislum and A.M.D. Jensen

The Danish Institute of Agricultural Sciences, Research Centre Flakkebjerg, DK 4200 Slagelse, Denmark

Endophyte-infection caused by the fungus Neotyphodium spp. is known to enhance quality traits in several grass species.  Results from tall fescue (Festuca arundinacea Schreb.) indicates, that endophyte-infected plants have a higher potential for seed production and growth under stressed conditions compared to endophyte-free plants.  This beneficial symbiosis has not yet been evaluated under Danish growing conditions.  Therefore, a preliminary pot experiment at Research Centre Flakkebjerg will be initiated in order to study physiological changes in perennial ryegrass (L. perenne) infected with the endophyte N. lolii L. Emphasis will be placed on the investigation of nitrogen and carbon metabolism.

Plants will be grown at two nitrogen levels, and the following parameters investigated on-line: photosynthesis and chlorophyll fluorescence.  This will be followed by growth analysis (fresh weight, leaf area, LAI, and analysis of C/N, D¹³ C ratios in freeze dried plant samples) of infected and uninfected clones of perennial ryegrass cv.  Delaware.  The project is preliminary in order to generate information for a more detailed project.