Studies on the bacterial wilt of eggplants.

I. Varietial differences of hosts in reaction to the causal bacteria.

Abstract

The present paper reported the results of experiments on the varietal resistance of eggplants to the bacterial wilt disease caused by Pseudomonas solanacearum, using two varieties, Daisen Maru No. 2 (susceptible) and Durable Shinkuro (resistant). From the morphological observations, the writer found cicatrice around the affected parts of eggplants. There were no essential differences, in these morphological barriers between the two varieties used.
No definite bacteriostatic effect in the exuded juice from the surface of both plants or in the expressed juice of plant was observed. The growth of the bacteria on the surface of plant, however, was definitely suppressed in the resistant variety.
The writer also observed a change in the population of the pathogenic bacteria within leaf tissues of both plants after the artificial injection. After forty eight hours, the writer found a large difference in the population of bacteria in the two plant tissues, showing the acceleration in Daisen Maru and the inhibition in Durable Shinkuro.
The chromatographic separation of the expressed juice was also performed. The treated papers were cut into three parts and dried. They were called C, B, and A from the top, respectively. A₁, B₁, C₁ belong to Daisen Maru, and A₂, B₂, C₂ to Durable Shinkuro. The writer extracted the substances of every part of the papers into distilled water with the following eight combinations: A₁B₁C₁, A₂B₁C₁, A₁B₂C₁, A₁B₁C₂, A₂B₂C₂, A₁B₂C₂, A₂B₁C₂, A₂B₂C₁. Thus the suppressive effect of these extracts upon bacterial growth was examined. From the results of these experiments, the writer confirmed the most strongest suppressive effect in C fraction of Shinkuro juice.