铜离子胁迫对苦草生长特性及生理指标的影响

Effect of Copper Ion Stress on Growth and Physiological Parameters of Vallisneria natans

设置0、1、2、4和6 mg.L-15个Cu2+浓度梯度,研究Cu2+胁迫对苦草生长特性和生理指标的影响。结果表明,Cu2+对苦草的胁迫作用明显,当ρ(Cu2+)为2 mg.L-1时,苦草生长受到抑制,株高变小,鲜质量下降,但仍能生存;当ρ(Cu2+)为4 mg.L-1时,出现明显受抑制现象,在持续胁迫30 d后,苦草外侧叶片出现腐烂变黑。微量的Cu2+有利于激活过氧化氢酶(CAT)活性,增强植株的抗逆性。CAT活性对逆境的响应早于MDA和H2O2含量,因此监测CAT活性的变化对苦草的抗逆生理研究更具时效性和准确性。当ρ(Cu2+)为2 mg.L-1时,苦草生长受到抑制,高于此浓度的Cu2+污染水体不宜建植苦草沉水植被净化系统。

An experiment was designed to have 5 treatments, i.e. 0, 1, 2, 4 and 6 mg · L-1 of p（ Cu2 ＋ ） to explore effects of Cu2 ＋ on growth and physiological indices of Vallisneria natans. Results show that the effect of Cu2 ＋ stress on V. natans was significant. When p （ Cu2 ＋ ） was 2 mg·L -1, growth of V. natans was inhibited with the plants shortened in plant height and reduced in fresh weight, but they still survived. When p （ Cu2＋ ） was 4 mg· L- 1 , the phenomena of inhibition became more obvious on the plants, of which the outer leaves began to decay and turn black after 30 days of stress. A trace amount of Cu2＋ was conducive to activation of catalase （CAT） and enhancement of stress resistance of the plants. The experiment found that CAT reacted earlier than MDA and H2O2 did, therefore, it was more accurate and effective to monitor changes in CAT activity for physiological studies of stress resistance of V. natans. As 2 mg· L-1 of p （ Cu2＋ ） can inhibit the growth of V. natans, so that, it is not suitable to build any Cu2 ＋ -contaminated wastewater purification system with V. natans as submerged vegetation when Cu2＋ concentration in the wastewater is higher than 2 mg · L-1.