洞庭湖湿地镉富集植物蒌蒿（Artemisia selengensis）的抗氧化机理研究

以生长于洞庭湖湿地的重金属Cd的高富集植物——蒌蒿（Artemisia selengensis Turcz.）为试材,采用水培方法,对其在Cd2＋胁迫下的抗氧化机理进行研究。结果表明：（1）蒌蒿是一种对重金属Cd有极强耐受能力的植物,试验期内,低于80mg·L-1的Cd2＋处理不使其表现出外观受害症状;（2）蒌蒿叶片中三种抗氧化酶活性在Cd2＋胁迫下呈现出不同的变化特征：40mg·L-1以内的Cd2＋对植株SOD活性具有显著促进作用,40mg·L-1以上则抑制其活性;POD对Cd2＋的耐受能力较强,高达160mg·L-1的Cd2＋仍可提高其活性,且活性变化随处理时间的不同而不同;植株CAT的活性受Cd2＋影响明显,5～20mg·L-1的Cd2＋对其有显著促进作用,40mg·L-1的Cd2＋在处理前期有利于植株CAT活性的提高,后期则导致其下降。蒌蒿对Cd2＋胁迫的抗氧化机理应从处理浓度和处理时间两方面进行综合评价。

Research of the antioxidant mechanism of Cd Accumulating Plant Artemisia selengensis Turcz.from the Dongting Lake

With different concentrations of Cd2＋ processing, a hydroponics experiment was carried out to explore the antioxidant mechanism of Cd accumulating plant Artemisia selengensis Turcz. from the Dongting Lake. The following results were obtained： （1） Artemisia selengensis Turcz. is a kind of plant with extreme ability to endure the heavy metal Cd, and doesn’t display the symptom of injury in its outward appearance within 80 mg·L-1. （2） The activities of SOD, POD and CAT present different variations during the trial period as following： The Cd2＋ within 40 mg·L-1 promotes the activity of SOD dramatically, and suppresses it when the concentration of Cd2＋ is higher than 40 mg·L-1. The activity of POD is still improved while the concentration of Cd2＋ goes up to 160 mg·L-1, and changes obviously with processing time. The activity of CAT is significantly influenced by Cd2＋, and is promoted greatly within the concentration from 5 mg·L-1 to 20 mg·L-1. It is notable that Cd2＋ of 40 mg·L-1 can increase the activity of CAT in the early stage, but decrease in the late. In conclusion, the antioxidant mechanism of Artemisia selengensis Turcz. should be synthetically evaluated from the two aspects of concentration and processing time of Cd2＋.