鬼针草对重金属镉的耐受性和抗氧化酶响应特征研究

Study on Tolerance and Antioxidant Enzyme Response Characteristics of Bidens pilosa L.to Cadmium

采用营养液栽培的方式,设置不同浓度Cd(0、20、40、80 mg/L和160 mg/L)胁迫处理,探究不同浓度下鬼针草的生长、耐受能力和抗氧化酶变化特征.结果表明:随Cd胁迫浓度升高,鬼针草生长受抑制加重,株高和生物量显著下降,Cd浓度为20 mg/L时根系耐性系数达最大为0.60,高于该浓度鬼针草生长发育受阻.植株Cd含量随胁迫浓度增加而升高,根部最高含量达1203.64 mg/kg,Cd1(20 mg/L)处理时Cd富集总量最大,后逐渐减小.抗氧化酶活性(过氧化物酶、超氧化物歧化酶和过氧化氢酶)呈现先升后降再升高的趋势,表现出对Cd胁迫的响应过程,其中超氧化物歧化酶活性变化与鬼针草Cd的吸收呈极显著正相关(P<0.01).研究表明鬼针草对Cd有较强吸收能力,适用于有效Cd浓度低于20 mg/L的污染土壤修复.

Nutrient solution cultivation was used to set up stress treatments with different concentrations of Cd(0,20,40,80 mg/L and 160 mg/L),and the growth,tolerance and antioxidant enzyme changes of Bidens pilosa L.were investigatived under different concentrations of Cd.The results showed that with increasing Cd stress concentration,the growth of B.pilosa was inhibited and suppressed.Plant height and biomass significantly decreased.The root tolerance coefficient reached a maximum of 0.60 at a Cd concentration of 20 mg/L.The Cd content in the plant increased with the stress concentration,with the highest content of 1203.64 mg/kg in the roots.The total Cd accumulation reached its maximum in the Cd1(20 mg/L)treatment and gradually decreased afterward.The activities of the antioxidant enzymes(SOD,POD,CAT)showed a trend of initial increase,decrease,and then increase again,indicating a response process to Cd stress.The change in SOD activity was highly positively correlated(P<0.01)with the Cd absorption in B.pilosa.This study demonstrates that B.pilosa has a strong Cd absorption capacity and is suitable for the remediation of contaminated soils with Cd concentrations lower than 20 mg/L.It also provides a preliminary exploration of the response mechanism of the antioxidant system in B.pilosa to stress,which can serve as a reference for the phytoremediation of Cd-contaminated soils.