Abstract
To elucidate the relation between the staining with dyes and the starch accumulation in the surrounding region of the spots in rice leaves infected by Cochliobolus miyabeanus, degree of staining in every region of diseased leaves was observed.
Necrotic lesions are slightly stained with some dyes, but mesophyll tissues of veneneous regions were not stained with most of the dyes used. Surrounding region of diseased lesions were stained somewhat weaker with basic dyes than the healthy parts of diseased leaves in the early stage of spot enlargement (up to the second day after inoculation), but this difference disappeared in the later stage (after the third day). Acidic dyes stained this region normally in all stage of spot enlargement, and acid fuchsin was exceptional, not only in veneneous region but also in surrounding of it, as it stained the surrounding deeper than the healthy parts. From these facts, ion charge of the surrounding region is considered to be positive especially in the early stage of spot enlargement.
At 24 hours after inoculation, the region with abnormally high starch accumulation (St), region stained with acid fuchsin (Af), region which was not stained with basic fuchsin or light green (bf or lg respectively) showed the relation Af>>St>bf=lg. It seems that in this stage, there is no close relation between areas of abnormal staining and abnormal starch distribution in diseased leaves.
