Abstract
A growth-depressing substance to young roots of rice seedlings was assumed to be existed in the culture medium which was inoculated with Xanthomonas oryzae. In order to isolate the active principle in pure crystal state and to identify chemically, the following procedures were adopted: The Wakimoto's potato semi-synthetic culture medium was prepared, inoculated with the causal bacterium and kept at 28°C in shaking conditions. Seven days after, the culture solution was extracted with ethylether and then re-fractionated to acidic part. After steam-distillation, the residue was submitted to column-chromatography over silica gel, to elute the biologically active zone by chroloform and to fractionate by fraction collecter. Finally, about 50mg of the crystal was obtained in pure state from 10l of the inoculated culture medium by the above-mentioned procedures. The melting point lies at 76.5°C and was not depressed by admixture with authentic phenyl-acetic acid. The substance was identical in infrared spectrum with authentic phenylacetic acid.
Judging from these characters, the authors concluded that the growth-depressing substance to young roots of rice seedlings which was produced by X. oryzae in culture was identical with phenylacetic acid.
