Patho-Physiological Studies on the Insect Gall Tissue of Distylium racemosum SIEB, et ZUCC. : Ⅱ. Observation on the Host-Parasite Interrelation for the Maintenance of the Gall Tissue

1. For the purpose of investigating on the host-parasite interrelation for the maintenance of the gall tissue, insect gall (Globular gall) of Distylum racemosum SIEB. Et ZUCC. And the causal aphid, Astegopleryx globuli MONZEN are used in these experiments. 2. By making a small hole on the surface of the Gall, the aphids were carefully removed with small brush from the gall before the stage of natural discharge of the aphid from the Gall, and the change of the gall tissue was observed in every four days. 3. On the 4th day after the treatment, about half of 16 treated aphid-free galls became softened and faded in color, and after 8 days most of them were faded to brownish color, 14 treated aphids-contained galls showed no change in appearance with one exception. 4. The dehydrogenase activity in the above materials was detected with TTC reagent of cysto-chemical technique. Eight days after the treatment, the dehydro-genase activity of the treated aphids-contained galls showed to be the same to the untreated natural Gall, though it was scarce in the aphid-free galls. 5. A schematic diagram on the reaction of the host tissue cells to the causal agents in the case of the progressive (galls) or of the regressive disorders(spotted diseases) was sugested by the writer. The host-parasite interrelation in the gall seems to be a “parasitic symbiosis” in a limited part at least.