1986 Volume 52 Issue 3 Pages 460-465
The production of ethylene in primary leaves of oat following inoculation with uredospores of Puccinia coronata f. sp. avenae was studied. Leaves of cv. Shokan 1 exhibited two distinct peaks of ethylene production at 8 hr and 35 hr after inoculation with incompatible race 226, while the leaves inoculated with compatible race 203 exhibited only one peak at 8 hr. Causal relationship between the increase of ethylene level and resistance expression was examined by the blockage experiments of resistance using NaN3, CoCl2, diethyldithiocarbamic acid, 2, 4-dinitrophenol, salicylhydroxamic acid, propyl gallate, cordycepin and blasticidin S or by the double inoculation technique. The results indicated that the ethylene production is not responsible for the limitation of fungal development. Exogenous supply of ethylene and its precursor, 1-aminocyclopropane-carboxylic acid, had no effect on uredosorus formation on susceptible Pc cultivars. It was suggested that enhanced synthesis of ethylene would not be a causal event but rather be a part of spurious phenomena associated with resistance response.