[The effect of infection by Fusarium solani f. sp. batatas on endogenous hormone levels in sweet potato seedling].

The endogenous hormone ABA concentrations increased in the leaves, shoots and roots of sweet potato plants infected with Fusarium solani f. sp. batatas (FSB) or treated by its culture filtrate. The accumulation of ABA occurred firstly in the roots, but the highest concentration was in the shoots. The endogenous GA(1/3) concentration of leaves, shoots and roots of infected sweet potato kept at markedly low levels during the period of experiments.The ABA concentration of sweet potato seedlings increased observably after 9 h treatment with FSB culture filtrate, but decreased significantly after 15 h, and the GA(1/3) concentration increased markedly after 15 h treatment with 10(1), 10(2) dilution of FSB culture filtrate (after 12 h treatment with 10(3) dilution). The disease symptoms may be induced by the changes in concentration of ABA and GA(1/3) in the plants. The root rot-infected sweet potatoes grew upright without tailing, having aerial roots in knots near the ground, and were in full bloom in autumn.