Germination Promotant for Plants Seed, produced by Microorganisms

Part III. Germination Promotant for Rice Plant Seeds, produced by Streptomyces sp. S-580. Isolation and Structure of an Active Neutral Crystal (Factor-E)

Abstract

A neutral crystalline substance (Factor-E), which is effective for the germination of rice plant seeds at the dilution of 10^-5_??_10^-7, was isolated from the active crude syrup extracted from the culture filtrate of Streptomyces sp. S-580. And Factor-E has been proved by hydrolysis and synthesis to be L-prolyl-L-valine anhydride (diketopiperazine), which has been proved to be the new diketopiperazine.