硒对镉胁迫下白术抗氧化能力的影响

[目的]探讨硒对镉胁迫下白术抗氧化能力的影响,为白术种植中重金属污染防治提供参考.[方法]采用室内水培试验,利用1/2 Hoagland＇s营养液培养白术幼苗30 d后,按营养液中单独加入4 mmol/L镉及不同浓度的硒（Na2SeO3）（10、20、40、60、80和100 μmol/L）分别与4 mmol/L镉混合设7个处理,另设不添加镉和硒的营养液处理为对照,48 h后取各处理的白术叶片进行相关生理指标测定.[结果]镉胁迫导致白术的H2O2和丙二醛水平显著升高,而超氧化物歧化酶（SOD）和过氧化酶（CAT）酶活性下降.在镉胁迫下,添加不同浓度的硒后,白术抗氧化系统出现不同的反应.当加入相对较低浓度（10～60 μmol/L）的硒对,SOD和CAT酶活性显著增加,而H2O2和丙二醛水平显著下降,表明镉胁迫造成的过氧化伤害有所减轻;而加入相对较高浓度（80～100 μmol/L）的硒对,SOD和CAT酶活性下降,H2O2和丙二醛水平上升,表明镉胁迫造成的过氧化伤害没有缓解.[结论]较低浓度的硒处理有利于增强镉胁迫下白术幼苗抗氧化能力.

Effects of selenium on antioxidant ability of Atractylodes macrocephala Koidz.under cadmium stress

[Objective]The protective effect of selenium （Se） against cadmium （Cd） stress in Atractylodes macrocephala seedlings was revealed to provide references for controlling the heavy metal pollution in cultivation of this crop.[Method]The hydroponics experiment of Atractylodes macrocephala seedlings was carried out in 1/2 Hoagland medium.A month later,the growth medium was supplemented with 4 mmol/L Cd in the form of CdCl2 and different concentrations of Se （10,20,40,60,80 and 100 μmol/L） in the form of Na2SeO3.Se and Cd were not added to the control.Leaves were harvested （48 h after treatment） for the study of physiological indices.[Result] Cadmium stress resulted in the significant increase of H2O2 and MDA content,whereas the SOD and CAT activities decreased,which meant there was oxidative damage in Atractylodes macrocephala that caused by Cd stress.Under Cd stress,the antioxidant system of Atractylodes macrocephala showed different responses when different concentrations of Se were added.The relatively lower concentrations of Se （10-60 μmol/L） supply decreased H2O2 and MDA content,and increased the SOD and CAT activities,which meant there was less oxidative damage in Atractylodes macrocephala.However,relatively higher concentrations of Se （80-100 μmol/L） supply increased the H2O2 and MDA production,and decreased the SOD and CAT activities,which meant the oxidative damage caused by Cd stress didn＇t lessen.[Conclusion] 10-60 μmol/L selenium is favorable for enhancing antioxidant ability of Atractylodes macrocephala seedlings.