关于海带“叶片点烂病”的初步研究

在自然界中,无论野生的或栽培的植物,都可能发生病害。海带(Laminaria japonicaAresch)也不例外。自开展人工养殖以来,几乎每年都有病害发生。1958年以前,大面积养殖生产还局限于水质肥沃的海区时,常常发生叶片绿烂病。1959年海带养殖在全国沿海推广以后,在水质瘠贫的海区,则常常发生各种白烂病。1959年5月和1960年4月,辽宁金县大

PRELIMINARY STUDIES ON THE SPOT ROT DISEASE OF HAIDAI FRONDS

On the basis of experim ental atudies on the spat rot disease of the fronds of the haidai, Laminaria jnponive, the following results had been obtained. 1.The disease developed more seriously in shallow water regions where water circulation waa slow, and the spread more rapidly with increase of water transparency. 2.No bacteria were iaolated from the healthy parts of the diseaaed frvuda.Bacteria isolated from the diseased parts were found to be Cram-negative bacilli without spores, and inoculation of these bacteria into healthy fronds did not produce similar diseases. 3.Anatomy of the diseased fronds showed no bacteria in tissues in the early stages of the disease; in later stages, the cells last all their pigments, only the protoplasm being left, but the epidermal cells of the ether shadowed side of the fronds remaining healthy; when the white spots developed further and eventually merged with the neighboring spots into large a hole, often a pigmentrd ring was found around the hole. On the basis of these observations, it was concluded that the spot rot disease is physiological in nature and is not caused by pathogenes, although the bacterial growth which eventually followed does worsen the disease. Therefvre the authors suggest that to prevent the disease, means must be taken to make better water circulation in the cultivation regions and to lower the cultivation depth of the haidai at the time when the Laminaria is moat easily infected with this disease.