背角无齿蚌幼蚌心率对镉暴露胁迫的响应及预警评估

为探究“淡水贝类观察”研究体系专用指示生物“标准化”背角无齿蚌(Anodonta woodiana)幼蚌的心率对镉(Cd)暴露胁迫的响应及预警评估,在“非致死/非损伤”条件下,研究从心跳清晰可见至贝壳不再透明的典型生长阶段的早期幼蚌:EJ125日龄,壳长为(1.5±0.1)mm]、EJ255日龄,壳长为(10.5±0.6)mm]、EJ370日龄,壳长为(20.4±0.9)mm]和EJ485日龄,壳长为(30.0±2.0)mm]的心率规律,进而探索EJ4心率对不同浓度Cd2+(0.0025、0.005、0.025、0.1和0.5 mg/L)的毒性响应特征。结果显示,早期幼蚌心率总体无显著日变化(P>0.05);心率与日龄和壳长之间均呈显著的线性负相关(P<0.05);心率和暴露时间仅在0.0025和0.5 mg/L的Cd^2+暴露组之间呈显著线性负相关(P<0.05);所有暴露组的心率和暴露浓度之间均呈显著线性负相关(P<0.05)。本研究表明,利用“标准化”背角无齿蚌幼蚌的心率对Cd^2+浓度的响应特征,有潜力开发出基于心率为指示的新型水质Cd^2+污染预警监测系统。

Response of heart rates to cadmium-exposed stress and early warning capacity in Anodonta woodiana juveniles

This study investigates the response of heart rates to cadmium-related stress and its early warning capacity among juveniles of“standardized”Anodonta woodiana,a unique bioindicator used in the“Freshwater Mussel Watch”project.Heart rates of early juvenile mussels at several typical growth stages,from heartbeat-clearly-observed to shells-no-longer-transparent,i.e.,EJ125 days old;shell length(1.5±0.1)mm],EJ255 days old;shell length(10.5±0.6)mm],EJ370 days old;shell length(20.4±0.9)mm],and EJ485 days old;shell length(30.0±2.0)mm],were studied under non-lethal/non-injury conditions.The response of heart rates to different concentrations of Cd^2+(0.0025,0.005,0.025,0.1,and 0.5 mg/L)in EJ4 were examined.The results show that heart rates of early juveniles generally differed little between ante meridiem and post meridiem(P>0.05)states.Heart rates were linearly and negatively correlated with age and shell length(P<0.05).Heart rates were linearly and negatively correlated with exposure time in the exposure groups of 0.0025 and 0.5 mg/L Cd^2+(P<0.05).However,heart rates were linearly and negatively correlated with Cd^2+ concentrations in all exposure groups(P<0.05).These results indicate that a new early warning/monitoring system for Cd^2+ contamination may be developed using responses characteristic of“standardized”A.woodiana to Cd2+concentrations.