Histology and cytology observation on the rot disease of Laminaria japonica caused by alginic acid decomposing bacteria

The changes of histology and cytology in Laminaria japonica were studied by art ificial infection and microscopic observation. The results showed as follow s: 1. The endodermis was infected f irstly by alginic acid decomposing bacteria ; the exodermis , pith and epidermis were infected later. 2. The damage of endodermis was heaviest , exodermis and pith were damaged less heavily, and the effect of alginic acid decomposing bacteria on epidermis was least remarkable. 3. a lot of storage material was accumulated in endodermic cells of infected laminaria japonica compared with control; the diameter of storage particles was from 1. 5 Lm to 4. 0 Lm, and the average value was 2. 7Lm.