水生植物有翅星蕨(Microsorum pteropus)对镉的超富集能力及抗性生理研究

Hyperaccumulation capacity and resistance physiology of Microsorum pteropus, an aquatic fern to cadmium

超富集植物能耐受高浓度的重金属并将其储存于植物各组织中,对于重金属污染环境的修复具有重要意义.本文以沉水植物有翅星蕨(Microsorum pteropus)为研究对象,设置了低浓度镉暴露组(0,0.1,1,5,10,20 mg/L)和高浓度镉暴露组(0.20,40,60,80,100 mg/L),暴露7天,发现有翅星蕨各组织镉富集浓度的大小顺序为:不定根>羽片>叶柄>根状茎,在0.1mg/L镉暴露情况下,不定根的最大生物富集系数达920.21.各暴露组有翅星蕨对培养液中Cd的去除效率为39.12%~53.99%.当镉暴露浓度为60mg/L时,不定根和羽片中镉的富集浓度分别达到了(3738.39±348.03)及(10652.53±2477.74)mg/kg,具有极强的镉富集能力.同时,各暴露组有翅星蕨的叶绿素、丙二醛、过氧化物酶与超氧化物歧化酶活性、以及叶绿素荧光参数等生理生化和光合作用指标相较对照组并未出现显著的变化.研究表明,有翅星蕨对水体中的Cd具有超强的富集能力,可用于镉污染水体的修复.

Hyperaccumulators play very important role in phytoremediation of environment polluted by exceed heavy metals, since they could hyperaccumulate heavy metals in their tissues and tolerant high concentrations of heavy metals. The present study reported an aquatic fern-Microsorum pteropus, which might has the potential to be a hyperaccumulator for cadmium（Cd） in water environment. We set two group exposure experiments with different Cd concentrations, low dose groups（0, 0.1,1,5, 10, 20 mg/L） and high dose groups（0, 20, 40, 60, 80, 100 mg/L）. After seven days Cd-exposure, we found that the order of Cd accumulation concentrations in the tissues was adventitious rootleafpetiolerhizome, and that the bioconcentration factors（BCF） could reach as high as 920.21 in adventitious root under 0.1 mg/L Cd-exposure.The remove efficiency of the plant to Cd varied from 39.12% to 53.99% in different Cd-exposure concentrations after seven days culture. At 60 mg/L Cd exposure level, the Cd accumulation concentrations in the adventitious root and leaf tissues were（3738.39±348.03）,（10652.53±2477.74） mg/kg, respectively. Meanwhile, chlorophyll concentrations,malondialdehyde（MDA） concentrations, peroxidase（POD） activity, superoxide dismutase（SOD） activity and chlorophyll fluorescence parameters showed no significant change between Cd treatments and the control. These results mean that Microsorum pteropus have significant hyperaccumulation capacity and remarkable resistance to Cd, which might suggest that this aquatic fern could service as a hyperaccumulator for the phytoremediation of Cd-polluted water environment.