铜胁迫对白茅根际和非根际土壤酶活性影响的研究

Physiological Response of Imperata cylindrica var.majo Seedlings on Growth and Antioxidant Enzyme System under Cu Stress

通过盆栽实验研究了重金属Cu递进胁迫对白茅根际和非根际土壤酶活性的影响。结果表明,随着Cu浓度的增加,根际和非根际土壤的pH值下降、土壤酸化,而电导率呈持续上升,但根际土壤的pH值持续高于非根际土壤且更接近于中性。在梯度浓度的重金属Cu胁迫下,根际和非根际蔗糖酶活性随Cu浓度增加均表现出先升后降的趋势,但根际土壤的蔗糖酶活性在Cu浓度为1000 mg kg-1时达到峰值,而非根际土壤则在Cu浓度为500 mg kg-1时已到达峰值。白茅根际和非根际土壤中磷酸酶、脲酶和过氧化氢酶活性受Cu离子的影响均表现出持续下降的趋势,但各酶受抑制率各不相同。对梯度浓度Cu胁迫下的白茅根际和非根际土壤酶活性而言,四种酶在根际土壤中的活性普遍高于非根际土壤,且Cu2+对根际酶活性的抑制率也大于非根际土壤酶。对重金属单Cu污染敏感的土壤酶类依次为磷酸酶>蔗糖酶>脲酶>过氧化氢酶,其中磷酸酶可作为检测污染土壤的指示酶。

The effects of copper（Cu） progressive stress on the soil enzymes system of I.cylindrica var.majo.were studied by pot experiments.The result showed that the values of electric conductivity increased and the pH values decreased gradually with the increase of concentration of Cu;however,the pH values in rhizosphere soils were higher than in non-rhizosphere soils.Under progressive stress treatments of Cu,the invertase activaties in rhizosphere and non-rhizosphere soils could be improved under low concentration of Cu pollution,reaching their peaks at Cu concentration of 1000 mg kg-1 in rhizosphere soils and 500 mg kg-1 in non-rhizosphere samples.The activities of invertase,urease,phosphatase and catalase decreased for different suppressed degree with the increase of concentration of Cu.However,the enzymatic activities and their degree of being suppressed in rhizosphere zones soils were all higher than in non-rhizosphere.Under single treatments of Cu,the sensitive degree of enzymatic activities was： phosphataseinvertaseureasecatalase,so the phosphatase could all be used as the best indices of evaluating the quality of soil environment.