Abstract
The effect of glucose-supply on the formation of hypersensitive mesophyll collapse and the fungal development was studied using barley cultivar, Turkey 290 infected with Erysiphe graminis hordei, race I. The inhibitory effect of glucose on the formation of collapsed mesophyll cells was parallel to the increased concentration of supplied glucose. The most effective time of glucose-supply for inhibiting the formation of collapsed mesophyll cells was the stage before the immature haustorial formation. The fluorescent microscopic observation indicated that glucose-supply inhibited the fluorescent appearance of mesophyll cells, but not epidermal cells. It was suggested that supplied glucose might regulate the mechanism of mesophyll cell collapse which was activated during the stage of the primary haustorial formation.
By the glucose-supply it was clearly shown that there was no correlation between the rate of mesophyll collapse and the fungal development. The restriction of fungal growth was detected before the formation of collapsed mesophyll cells 2 days after inoculation. It was, therefore, assumed that the collapse of mesophyll cells is not causally related to the resistance in powdery mildew of barley.
