THE DISEASE OF THE CULTURED PORPHYRA, WITH SPECIAL REFERENCE TO THE CANCER-DISEASE AND THE CHYTRID-DISEASE WHICH OCCURRED AT THE CULTURE FIELD IN TOKYO-BAY DURING 1959-1960

The yields of the cultured Porphyra (Nori) in the Nori fields near the coast of Tokyo City were short in the last season covering from autumn in 1959 till late spring in 1960. The damage seemed to be caused chiefly from the Cancer-disease and the Chytrid-disease which were raging continuously for all the harvest season. In the Cancer-disease, the symptoms of the affected part showed some variations in the surface views (figs. 1-4) or in the transverse sections of the frond (figs. 10, 11, 21). In some cases many abnormally swollen cells appeared on the apparently healthy frond, then most of them started into abnormal cell-divisions to make cancer-galls while some of them remained without any change in shape for certain periods (figs. 5, 6, 8, 9). In the Chytrid-disease, a Chytrid Olpidiopsis sp. nov. was constantly observed on the affected fronds which were collected at any place in any season. In the beginning of the season the Olpidiopsis occurred even on the young of Porphyra, after then the parasite became more numerous invading in both the young and mature fronds (fig. 14). Sometimes, the host-cells became swollen, on which the abnormal cell divisions took place to make the, cancer-galls. (figs. 3, 7, 8, 16). In the Nori-field, the cancer-galls, the swollen cells, and the Olpidiopsis-parasites were observed on the same frond in an aspect mixed with each other or with patterns produced by the other diseases including red-disease or white-disease. It was found that the cancer-galls and the Olpidiopsis-parasites occur also on the Ulothrix, the Monostroma and the Bangia which were growing associated with each other on the Nori-hibi (collector-net), but not so frequently as on the Porphyra (figs. 2, 9, 12, 13, 20). On the other hand it was also found, through culture experiments in the laboratory, that the abnormally swollen cells and the cancer-galls occur on the fronds of several kinds of algae including Bangia, Ulothrix, Monostroma, Enteromorpha, and Ulva when they were cultured in the medium containing respectively the Phenol (C6H5OH), trichlene (Cl-CH-C*Cl2) or Potassium cyanide (KCN) (figs. 8, 9, 10, 16, 17). Besides, it was found that the growth-rate and the propagation of Olpidiopsis infested on those algae are also promoted by the same chemical agents mentioned above (figs. 19, 20, 21, and Table 1). From these observations in the field and the culture experiments in the laboratory, it is suggested that the cancer-disease and the Chytrid-disease may