铜对紫背浮萍的影响

利用紫萍(Spirodela polyrhiza)作材料,在实验室条件下研究了增加铜对紫萍生长、光合作用色素含量、叶绿素a荧光的产生和植物体内铜累积的影响。结果表明,环境中增加1μmol L-1d的Cu2+时即可显著地抑制紫萍的生长(用鲜重和干重表示),随增加的铜的量加大,对生长的抑制作用增加,鲜重在8 μmol L-1Cu2+时,干重在2 μmol L-1 Cu2+以上时出现负增长;铜水平的升高可使叶绿素含量大幅下降,但对类胡萝卜素的含量影响不大;对叶绿素a荧光的产生也有影响,短时间的处理(24 h内)使Fo和Fm升高,但Fv/Fm变化很小,随着处理时间的延长和处理浓度的增加,Fo和Fm下降至很低水平,特别是Fm下降更快,以至Fv/Fm可能出现负值,表明光合作用器官已受到破坏;当铜处理水平增加时植物体内的铜含量水平也增加,表明其对铜有一定的累积作用,但因为在高铜浓度水平下植物的生物量显著下降,因而从植物修复的角度考虑,在中等或微量铜污染的情况下,才能选择适宜来源的紫萍用于进行铜污染环境的植物修复。

Effects of enriched-copper on Spirodela polyrhiza

The effects of copper on growth,pigment content,chlorophyll a fluorescence and Cu accumulation in tissue of Spirodela polyrhiza were conducted. The results showed that copper could depress the growth adversely on both fresh weight and dry weight basis. And the fresh weight would be negative growth in medium of copper-added at 8 μmol L-1 ,the dry weight at 2 μmol L-1 ;the content of chlorophyll decreased greatly, but not the carotenoid;to chlorophyll a fluorescence,in first 24 h,copper made the Fo and Fm bigger,but not Fv/ Fm,then Fo and Fm reduced to very low,specially Fm.so as to Fv/Fm would be negative value,which demonstrated the photosynthesis apparatus had been damaged;copper content in tissue increased with the concentration of copper-added in medium, so the accumulation of copper happened. Because of biomass growth being very little at high copper concentration addition,so it is only available that using Spirodela polyrhiza to restore the environment polluted by low concentration copper.