1976 Volume 45 Issue 2 Pages 107-115
Various kinds of necroses found in bud tissues of hosts (chestnut trees) were caused by oviposition and consequent gall formation by chestnut gall wasps. Necroses resulted from resisting reaction against parasites were initiated in parenchymatous tissues around vascular bundles which intervened between gall and normal tissues, and were classified as Type III. In the case of reaction of Type III, the acidic pigments failed to transfer into galls, though they were artificially applied to be absorbed through the cut surface of stems.
Tannic substances stained with FeCl3 were scarcely found in gall tissues of resistant varieties. A small quantity of them were observed in the xylem and phloem of the host tissues but they were abundant in the parenchymatous tissues surrounding the vascular bundle system of normal tissues. The stainability was intensified not only in necrotic tissues and their adjacencies but also in the boundary regions of both gall and normal tissues. In the galls of susceptible varieties there were cells containing more tannins stained with FeCl3. Such a reaction was not observed in the nutritive cell layer which probably functioned as a source of diet for the parasites and was not intensified in the boundary regions of gall and normal tissues.
Reaction of catechol tannins to the vanillin-HCl reagent was marked in nearby cells of the necrotic regions and in tissues which were later expected to produce browning. In contranst with this phenomenon, gall tissues and developing leaves which might produce galls after the oviposition of wasps did not exhibit any vanillin-HCl reaction. Thus, it seems likely that catechol tannins can be regarded as polyphenols formed as a result of resisting reaction against the parasite.
Prior to the production of browning, cells which could be stained with Sudan Black B appeared in the affected area. Cells reacting to the Schiff′s or phloroglucin-HCl reagents were observed in the same area, also.
Differences of gall weight depended on two strains of causal gall wasps; one produced spring galls (Kuritama) in resistant varieties and the other did not. Survival rates of the two strains were the same, and polyphenolic reaction to FeCl3 was not detected in the larval bodies of the two strains studied.
