Preliminary Studies On The Radiation Biology Effect Of Molluscs

Marine molluscs occupy the important position in our country sea-farmingindustry. But, the molluscs are wild. Successive heavy mortalities have been themajor limiting factor in the development of this industry. There are severalsuspected causes of such massive mortality, such as: prevalence of virus andrickettsia-like pathogenic microorganisms, high stock densities which exceed carryingcapacity of sea areas, deterioration of water quality, etc. This paper was to study γray applied to shellfish breeding. The shellfish were exposed to cobalt-60 gamma ray at Laiyang AgricultureCollege Atomic Laboratory 2002. The radiation source is 12,000 Ci, at a rate of 1.5Gy / min. And the source was calculated at Chinese Science Institute of Electricity.The experiment was performed, derived from water. Before the materials were treated, they were grouped at random. The length,width, height, and wet weight of each was measured. The radiations were kepttemporarily with the nature sea water in Chinese Science Institute of Oceanology aftertreated. The radiations were fed with diatom three times everyday, and the waterwas changed once a day and the mortality rate was statisticed. Then the materialswere cultured in the sea of Qingdao. The survival rate and the growth rate weremeasured at certain stage. The research expresses high peak of mortality at 30 days or so in the molluscs.Instantaneous mortality and time variety is a single peak curve in the Pacific oysterand the Pacific abalone. Significant differences between the mortality rate andcultivation time and the irradiation dosage show evidently. 6英文摘要 The survival curve of the Pacific oyster is the typical parabola. A wide shoulderarea appeared in that lower than 80Gy. But in smaller than 60Gy, the survival was100 percenet. Higher than 80Gy, the oysters began to die. And the survival rate islinear decreasing as the dosage increasing. The survival curve of the Pacific abalonedescent very quick at low dosage, looks like a straight line. The survival curve ofthe Zhikong scallop a parabola. There is a slow-descendent shoulder area at lowdosage the curve, the high amount of area curve descent is quick. The low dosage of radiation has the incitement function to the growth of Pacificoyster, such as for shell length, shell width, shell height, and whole wet weight. Andthe growth rate of them are similar. Within the scope of 60Gy, the growth rateincreases with the irradiation dosage at first, then decreases. Within the scope of100Gy, the growth rates are all higher than the control. The result indicates thatirradiation can stimulate the growth rate of Pacific oyster at dosage from 8Gy to100Gy. And the most effect dosage is between 40 and 60Gy. The condition indexis accorded with the growth rate of the whole wet weight. The condition index canbe stimulated by γ ray. The biggest accelerant measures are within the scope of40~80Gy. The radiation repressed the growth of Pacific abalone. The growth rateof the control is 60 percent, and 40Gy is 38.45 percent at 2 month. The growth ratedecreases with the dose of radiation increases. Low dosage (≦40Gy) can incite thegrowth rate of Zhikong scallop. The most obvious is the whole wet weight(9.6%),which is 175.4 percent to the control. The gonad development of Zhikong scallop was damaged by γ ray irradiation. The gonad can not develop completely or develop spottedly. There are some better-developed follicle and some without-developed follicle in the ovary. The gonad was injured as the dosage increased. The Pacific oysters that survives after radiation are crossed. The hatching rateof 80 and 120Gy is lower than the control significantly. The growth rate of thelarvae slower than the control. And the grow...