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目的探讨稀土元素镧和镉联合暴露对蚤状溞生长及抗氧化酶活力的影响。方法将蚤状溞随机分为对照(双蒸水)组和低(1/8 LC50,0.012 5 mg/L)、中(1/4 LC50,0.025 mg/L)、高浓度(1/2 LC50,0.05 mg/L)镉暴露组及低、中、高浓度(镧和镉浓度比为1∶1)镧+镉联合暴露组,每组60只。分别于暴露第2、3、5、7天测定生长情况;于暴露12、24、48、72 h测定总超氧化物歧化酶(T-SOD)和过氧化氢酶(CAT)活力。结果与对照组比较,0.012 5 mg/L镉暴露组暴露第2天时生长率上升(P<0.05),0.025、0.05 mg/L镉暴露组暴露2~7天时的生长率均下降(P<0.05);与相应镉暴露组比较,0.012 5、0.025mg/L镧+镉联合暴露组生长率有不同程度上升(P<0.05),0.05 mg/L镧+镉联合暴露组生长率下降(P<0.05)。与对照组比较,0.012 5、0.025 mg/L镉暴露组T-SOD、CAT活力有不同程度上升(P<0.05),而0.05 mg/L镉暴露组T-SOD、CAT活力均下降(P<0.05);与相应镉暴露组比较,0.012 5、0.025 mg/L镧+镉联合暴露组T-SOD、CAT活力有不同程度上升(P<0.05),0.05 mg/L镧+镉联合暴露组CAT活力于暴露12 h时上升,48~72 h时下降,且不同程度地仍低于对照组。结论中、低浓度的镧能够缓解镉对蚤状溞生长的抑制和抗氧化酶活力的损伤。
Objective To investigate the effects of rare earth element La and Cd combined exposure on the growth and antioxidant enzyme activity of Daphnia magna. Methods Daphnia magna was randomly divided into control (double distilled water) group and low (1/8 LC50,0.012 5 mg / L) medium (1/4 LC50,0.025 mg / L), high concentration , 0.05 mg / L) cadmium exposure group and low, medium and high concentration (Lanthanum - Cadmium concentration ratio of 1: 1) lanthanum + cadmium exposure group, 60 rats in each group. The growth was measured on the 2nd, 3rd, 5th and 7th day after exposure. The activities of total superoxide dismutase (T-SOD) and catalase (CAT) were measured at 12,24,48 and 72 h after exposure. Results Compared with the control group, the growth rate of cadmium exposed group (0.012 5 mg / L) was increased on the second day (P <0.05), while the growth rate of exposed cadmium exposed group was decreased from 0.025 to 0.05 mg / L for 2-7 days (P <0.05 (P <0.05). Compared with the corresponding exposure group, the growth rate of lanthanum + cadmium exposure group (0.012 5,0.025 mg / L) increased to some extent (P < 0.05). Compared with the control group, the activities of T-SOD and CAT in the cadmium exposure group (0.012 5,0.025 mg / L) increased to some extent (P <0.05), while the activities of T-SOD and CAT decreased in the exposure group of 0.05 mg / L cadmium (P < 0.05). Compared with the corresponding exposure group, the activities of T-SOD and CAT in the combination of 0.012 5 and 0.025 mg / L lanthanum + cadmium increased to some extent (P <0.05) Vitality increased at 12 h of exposure and decreased at 48 to 72 h, and remained lower than the control group to varying degrees. Conclusions Medium and low concentrations of lanthanum can alleviate the inhibition of cadmium growth and the antioxidant enzyme activity.