土壤跳虫(Folsomia candida)对食物中铜污染物的吸收和排泄

重金属污染物在生物体内的累积、迁移和传递已成为当今的研究热点。土壤弹尾目昆虫作为土壤生态系统的重要组成部分,针对其对重金属的吸收、积累和排泄的动态过程以及相应解毒机制的研究意义重大。本研究通过弹尾目跳虫(Folsomia candida)对Cu的吸收-排泄效率实验发现,跳虫体内Cu含量随暴露时间的延长而显著增加(r~2=0.8878,F_(1,5)=29.59,P<0.01);跳虫体内Cu含量随排泄时间的延长而明显逐渐降低(r~2=0.7836,F_(1,3)=7.13,P<0.01)。跳虫对Cu的吸收-排泄Budget实验表明,只有少量的Cu被跳虫摄取到体内,其中小部分被体内组织消化吸收,大部分则可能通过中肠细胞的褪皮作用和产卵等方式排出体外。可见,褪皮和排卵是跳虫排泄重金属Cu的重要途径,跳虫对Cu具有较低的吸收率(8.13%)和较高的排泄率(57.3%),表明跳虫对Cu可能有较高的耐受性。

Assimilation and Excretion of Copper Contained in Food by Soil Collembolan (Folsomia candida)

Accumulation,transfer and transport of heavy metals in organisms have attracted increasing attention recently.As an important species in soil ecosystem,it is of great concern to investigate the process and mechanism of uptake,accumulation and excretion of heavy metals by collembolan.The study on the assimilation-excretion efficiency of copper by Folsomia candida（Collembola） was carried out.It is found that Cu content in F.candida increased significantly with the extension of exposure time(r² = 0.8878,F_1,5 = 29.59,P <0.01),whereas Cu content in F.candida decreased significantly with the extension of excretion time(r² = 0.7836,F_1,3 = 7.13,P <0.01)。Moreover,the assimilation-excretion budget results showed that only a small amount of Cu entered into F.candida body.The minor part was assimilated by F.candida tissues,the major part might be eliminated out of F.candida through exuviation of midgut cells and oviposition.It is concluded that exuviation and oviposition were important pathways to excrete Cu by F.candida.The low assimilation efficiency（8.13%） and high excretion efficiency（57.3%） of copper suggested the relative high tolerance of F.candida to copper pollution.