Cu2+胁迫对黑麦草(Lolium perenne L.)去除富营养化水体中氮、磷效果的影响

为探讨不同浓度Cu2 胁迫对黑麦草去除富营养化水体中N、P营养盐效果的影响,采用小试培养的方法,研究了Cu2 存在条件下黑麦草对水体中N、P去除的动力学过程及黑麦草植株对不同浓度Cu2 胁迫的生态响应.结果表明,0.1～2.0mg/LCu2 胁迫均降低了黑麦草对水中N、P营养盐的去除速率,其去除过程符合二阶动力学模型.黑麦草对水体中Cu2 亦有良好的去除作用,根部是积累重金属Cu的主要部位,其对Cu2 的吸收速率符合米氏动力学方程.较低浓度Cu2 (≤0.2mg/L)胁迫对黑麦草去除N、P的效果影响不大,并且能促进黑麦草生物量的增加,而较高浓度Cu2 (≥0.5mg/L)胁迫虽有促进根系数量增加的趋势,但明显抑制了黑麦草根伸长和叶片生长等作用,因而严重影响了黑麦草对水体中N、P的去除.

Effects of Cu2+ on Nitrogen and Phosphorus Removal by Ryegrass Cultivated in Eutrophic Water Body

Solution culture experiment was carried out to investigate the effects on the removal efficiencies of N and P by perennial ryegrass (Lolium perenne L.) under the Cu stress and the ecological response of ryegrass to various dosages of Cu2+. The results indicated that the removal efficiencies of N and P decreased under all the intimidating conditions compared with the control tanks, which followed the second-rate equation. The removal efficiencies of N and P and the plant growth at low Cu2+ concentrations (< or = 0.2 mg/L) were higher than those at high Cu2+ concentration (> or = 0.5 mg/L), and the biomass (dry weight) was increased at low Cu2+ concentrations (< or = 0.2 mg/L) relative to control solution. In addition, the plant was able to remove Cu2+ in the eutrophic water simultaneously, and the removal efficiencies under the high Cu2+ concentrations were higher than those under low Cu2+ concentrations. Results show that the root was the main section for accumulating Cu2+ and the data of Cu2+ uptake by perennial ryegrass fitted Michaelis-Menten kinetics equation. Perennial ryegrass were sensitive to Cu2+ treatment. Root elongation was reduced in Cu2+ treatment solutions, but the numbers of new-growth roots increased compared with those cultivated in control solution.