Studies On Biological Characteristics Of Infection-resistant Reaction Against Alginic Acid Decomposing Bacteria In Laminaria Japonica

The aquaculture industry in China is in a growth phase and sea kelp is one of the most commercialized seaweed species so far. However, the key link restricting the production growth in artificial breeding is the disease occurrence and the disease-resistance decreasing. It is of important meanings to study the mechanisms of disease occurrence in sea kelp farming.In this study, the Characteristics of growth and alginase production of alginic acid decomposing bacteria isolated from diseasing kelp were investigated. Meanwhile, the biological effect of infection by alginic acid decomposing bacteria was analysed in Laminaria japonica.The results were shown:The optimum conditions of growth and alginase production in strain A1 and A2 were sodium alginate 0.6～0.7% , NaCl 1.5%, culture temperature 20℃, pH7.5 .The changes of histology and cytology in Laminaria japonica were studied by artificial infection and microscopic observation.The results showed that the damage of endodermis was heaviest, exodermis and pith were damaged less heavier, and the effect of algnic acid decomposing bacteria infection on epidermis was not irremarkale.A lot of storage material was accumulated only in endodermic cells of infected laminaria japonica during infection by alginic acid...