盐度对管角螺胚胎发育的影响

在水温25.5~29.2℃的条件下,设11个盐度梯度对管角螺Hemifusus tuba(Gmelin)]的胚胎发育进行了观察和研究。结果显示:管角螺胚胎发育的适宜盐度范围为22~35,最适盐度范围为25~31;在适宜的盐度范围内,7~9 d发育的胚胎能完全消耗卵囊内的败育卵变为自身发育的营养物质,13~15 d形成稚螺雏形,31~34 d胚胎完成发育从卵囊内爬出;适宜盐度范围内各盐度对正常卵发育数量、孵化率无显著影响。低于其适宜盐度范围,胚胎发育在初始阶段便受抑制,盐度为16~19只有部分正常卵发育,需34~36 d才完成胚胎发育;高于适宜盐度范围的38、41两组,在6 d内对胚胎发育无影响,但6 d后影响显著。低盐度对胚胎发育影响较高盐度更为明显。

Effects of Salinity on Embryonic Development of Hemifusus tuba(Gmelin)

At sea water temperature of 25.5~29.2,the effects at eleven salinity grades on embryonic development of Hemifusus tuba(Gmelin) were studied.The results show that suitable salinity ranges from 22~25 for embryonic development of Hemifusus tuba(Gmelin),and the best suitable salinity for embryonic development of Hemifusus tuba(Gmelin) is between 25~31.Within the suitable salinity,developmental embryos can digest and absorb the abortive eggs in the egg capsula make its own nutritive substance complete in 7~9d,and juvenile primarily formed in 13~15d,and embryonic development is complete in 31~34 d.In addition,the number of developmental of normal eggs and hatching rates are not affected by salinity in suitable range.The development of embryos is inhibited in initial by salinity under suitable range,only a few normal eggs can normally develop and the embryos development can be finished in 34~36 d when in sea water of 16~19.Embryonic development is not affected when in sea water of 38 and 41 in 6d,but is inhibited from 6d onwards.The inhibition of embryonic development by low salinity is more obvious than that of high salinity above suitable range.