西瓜蔓割病の病理化学的研究

Abstract

1) In the present paper, the authors deal with the results of the experiments on the identification and isolation of wilt toxin by Fusarium bulbigenum var. niveum causing watermelon wilt.2) It was recognized that the wilt toxin, metabolited in the cultured filtrate was thermostable, non-volatile, dialyzable and adsorpted by 2% active carbon under a alkaline condition.3) Parallel was probably established between resistance and susceptibility of watermelon varieties to Fusarium wilt and sensitivity to cultured filtrate injury.4) Isolation processes of wilt toxin involved in the cultured filtrate or its mycelial mats were summarized as follows: The filtrate adjusted at pH 8.5 was adsorpted by 2% active carbon, its adsorpted carbon or dried mycelial mats were then eluted by aceton. Aceton solution was concentrated and dried up under a diminished pressure, resulted rich water residue was adjusted by NaHCO3 at pH 8.5, and then effective principle was extracted with ether. When ether solution was slowly concentrated, effective principle substance was precipitated. By recrystallizing from aceton, wilt toxin was obtained as crystal. The substance was prism like crystal, m. p. 138∼9°C., and soluble in alcohols, aceton, ether, chloroform, carbon tetrachloride or benzene, and insoluble in water, acid, alkali or ligroin.5) The present wilt toxin isolated was designated by the authors phytonivein. Watermelon cut stems and seedlings were permanently wilted by 10-5 phytonivein solution.