柄海鞘对锌的生物富集作用

Bioaccumulation of zinc in the ascidian Styela clava

摘要:

为研究柄海鞘对重金属Zn2+的生物富集作用,应用半静态双箱式生物富集动力学模型,通过非线性拟合得到相应的生物富集动力学参数.实验结果表明:柄海鞘对金属Zn2+具有一定的富集作用,对Zn2+的富集吸收速率常数k1和富集系数FBC均随外部水体中Zn2+质量浓度的增大而减小.富集平衡时,海鞘体内的锌含量(QAmax)与外部水体中Zn2+的质量浓度基本成正相关.柄海鞘不同器官中锌的质量浓度不同,依次为:生殖腺>消化腺>其他部分>外背囊.排出阶段锌在柄海鞘体内的生物学半衰期(B1/2)为11.36～23.98d.柄海鞘的生殖腺可蓄积大量的Zn2+,消化腺可较准确地反映海水中的Zn2+污染状况.

Abstract:

Based on the semi-static two compartment model,the bioaccumulation and elimination of zinc by tissues of Styela clava were investigated,the kinetic parameters of accumulation rate constant k 1,elimination rate constant k 2,bioconcentration factor F BC,biological half life B 1/2 and the maximum equilibrium concentration QAmax were obtained by non-linear regression.The results show that zinc can be accumulated by S.clava from aquatic environment.F BC decreases with the increasing metal concentration in water,and when the accumulation achieves balance,QAmax shows positive correlation to metal concentrations in water.Concentrations of zinc in different tissues of S.clava are listed as:gonad > digestive gland > other part > crust.B 1/2of zinc is 11.36-23.98 d in the phase of elimination.Zn can be accumulated in gonad of S.clava largely and the digestive gland can be used to monitor the pollution of zinc in sea water.