微囊藻毒素-LR和铜绿微囊藻裂解液对营养生长期水稻生理生化效应

Physiological and bio-chemical effects of pure MC-LR and Microcystis aeruginosa crude extracts on Oryza sativa L. at vegetative stage

选用微囊藻毒素-LR(MC-LR)纯品和铜绿微囊藻裂解液分别对水稻进行21d暴露处理,考察不同浓度(0.1,1.0和10.0μg/L)MC-LR纯品和不同浓度(0.002,0.02和0.2倍)裂解液对水稻株高、鲜重、根长、淀粉酶、碱性磷酸酶(AKP)、还原性谷光甘肽(GSH)和丙二醛(MDA)的影响.研究结果表明,MC-LR纯品能抑制水稻株高、根长及叶片中淀粉酶活性,且在较低浓度下水稻根长即出现显著响应.高浓度裂解液在水稻的生长发育方面更多地表现为对植株的刺激和促进作用,仅对水稻根长抑制显著.在生理生化方面,MC-LR纯品对叶片碱性磷酸酶活性无影响,但对GSH具有诱导作用,而裂解液对GSH、MDA和AKP都表现出显著抑制.该研究表明,MC-LR纯品和铜绿微囊藻裂解液对水稻的毒性效应存在差异,铜绿微囊藻裂解液中存在的其他毒素组分可能对水稻毒性效应影响较大.

In the present study,the changes of plant height,root length,plant fresh weight,amylase activity,AKP activity,GSH content and MDA content of rice(Oryza sativa L.)were investigated under the exposure to a series of concentrations of MC-LR(0.1μg/L,1.0μg/L and10.0μg/L)and Microcystis aeruginosa crude extracts(0.002lysate,0.02lysate and0.2lysate)for21d.Results showed that the plant height,root length and amylase activities of rice were decreased under the exposure of pure MC-LR.Root length was a sensitive indicator in rice for its quick response to MC-LR exposure in0.1μg/LMC-LR treatment group.However,Microcystis aeruginosa crude extracts with high concentration of MC-LR had positive effects on growth and development of rice except for root length.GSH content of rice was significantly induced in0.1μg/L MC-LR group,but no significant changes of AKP activity was observed in all pure MC-LR treatment groups.In contrast,GSH content,MDA content and AKP activity could be significant inhibited in rice exposed to Microcystis aeruginosa crude extracts.These results suggested that the toxicity mechanism of MC-LR to rice might be different from Microcystis aeruginosa crude extracts and other toxic components existed in Microcystis aeruginosa crude extracts may exert great influence on rice.