The relative tolerances of wild and cultivated oats to infection byErysiphe graminisf.sp.avenae: II. The effects of infection on photosynthesis and respiration

Abstract

The effects of infection by the powdery mildew fungusErysiphe graminisf.sp.avenaeon photosynthesis and respiration in the third leaf of one line of wild oat (Avena fatua) and two cultivars of cultivated oat (Avena sativa), Lustre and Peniarth, were studied. Gross and net photosynthesis and chlorophyll levels were reduced by infection in all three lines, but to the greatest extent in cv. Peniarth, and to the least extent in the wild oat. Infection increased respiration in the two cultivated oats, particularly in cv. Peniarth, but it had no significant effect on respiration in the wild oat. However, the highest level of mildew biomass developed on the wild oat, and so the study clearly demonstrated that the wild oat possessed more tolerance of infection than either of the two cultivated oats, particularly cv. Peniarth.