环境因子对两种海洋双壳类幼体趋性行为中的调节作用

EFFECTS OF ENVIRONMENTAL FACTORS ON THETAXIS BEHAVIOUR OF SINONOVACULA CONSTRICT AND CRASSOSTREA G7GAS LARVAE

本文研究了温度、盐度和重金属等几种因子对缢蛏和长牡蛎幼体趋地性和趋光性行为的影响。结果表明:1)降低温度能增强缢蛏幼体的正趋地性,而长牡蛎幼体却由正趋地性转变为负趋地性,同时两种幼体的正趋光性受到抑制作用;升高温度对缢蛏幼体趋光性的影响不明显,但能加强牡蛎幼体的正趋光性。2)盐度提高时缢蛏幼体的正趋光性趋于增强,正趋地性趋于减弱。3)重金属Cu和Zn在各自的亚致死浓度下具有提高缢蛏幼体正趋地性和降低正趋光性的作用,而牡蛎幼体的正趋地性却趋于减弱,正趋光性趋于增强。本文据上述幼体的行为变化,还讨论了这几种因子对幼体垂直分布的调节作用。

The effects of temperature, salinity, and heavy metals on the phototaxic and geotaxic responses of the larvae of S.constricta and C.gigas were examined under the laboratory conditions.The results may be summarized as follows: (1 )A decrease in temperature might increase the positive geotaxic response of S. constricta larvae while the oyster larvae (C.gigas) might change their positive geotaxis into negative response. Simulancously both larval photoresponses were inhibited. An increase in temperature had less effect on the photoresponse of S.constricta larvae but had an intensified response in oyster larvae. ( 2 ) An increased salinity would increase the positive photoresponse and decrease the positive geotaxis of S.constricta laruae. ( 3 ) Two heavy metals, copper and zinc, had an increased effect on the positive geotaxic response and decreased effect on the photoresponse of S.constricta larvae. The oyster larvae, however, response in an opposite manner, Based on their behavioural responses, it is suggested that the larvae of S.constricta are more sensitive to heavy metal pollution than C. gigas laivae. The mechanisms of environmental factors in regulating the depth distribution of bivalve larvae in the field are discussed.