Effects of calcium nitrate and chlortetracycline on papilla formation, ml-o resistance and susceptibility of barley to powdery mildew

摘要: Penetration sites of Erysiplie graminis f. sp. hordei on partially dissected coleoptiles near-isogenic resistant and susceptible ml-o barley were examined in vitro to study the effects Ca(NO 3 ) 2 Ca 2+ chelator ionophore, chloretracycline, penetration efficiency papilla formation. Compared water controls, incubation 10 m M allowed a marked expression resistance. Time-course studies incubated showed that papillae, average, initiated isoline 1·0 h before pegs; susceptible, 0·7 after. These differences coincident with 5% 62% frequency 87% 77% coleoptiles, respectively. Growth rates papillae two isolines not significantly different during first development ; however, twice size those at time peg initiation. In comparison , Chlortetracycline delayed initiation relative by 2·2 decreased nearly 30% increased 74% isoline, but caused no significant these parameters isoline. results suggested earliness response is an important component disease resistance mechanism, neutralized mechanism delaying average initiation, may be calcium-dependent.