汞胁迫对水葫芦光合特性和生理生化特征的影响

Effects of HgCl_2 on Photosynthetic Characteristics and Physiological and Biochemical Characteristics of Eichhornia crassipes

当前我国水体汞污染日益严重,由于其易迁移性和毒性,严重威胁着生态环境和人类的健康,寻找对汞胁迫具有一定抗性的水生植物已经刻不容缓。试验采用溶液培养法研究不同质量浓度的HgCl_2(0,2.5,5.0,10.0,20.0,40.0 mg·L^(-1))对水葫芦幼苗生长和发育的影响。结果表明,水葫芦鲜质量增长量、叶绿素含量、Pn值和SOD活性在低质量浓度的HgCl_2溶液中随着汞质量浓度的升高而增加,在质量浓度为5 mg·L^(-1)时达到最高点;但随着HgCl_2质量浓度进一步增大,这些指标值反而持续下降。Pro和SP含量在HgCl_2质量浓度为10 mg·L^(-1)时达到最高点,但当HgCl_2质量浓度达到20 mg·L^(-1)时较对照显著下降;而Gs,Ci,Tr值表现出先下降后上升的趋势,但各处理间差异不显著,其中,Ci,Tr值在HgCl_2质量浓度为5 mg·L^(-1)时达到最低值,Gs在10mg·L^(-1)时达到最低值;MDA含量和POD活性则随着HgCl_2质量浓度的升高而上升。水葫芦对10 mg·L^(-1)以下的HgCl_2胁迫具有较好的适应性,且可促进水葫芦的生长;但高质量浓度HgCl_2对水葫芦的生长则有抑制作用。研究结果可为水葫芦对Hg2+胁迫的适应机制提供一定理论依据。

The water mercury pollution has been seriously polluted in recently years in our country, because of its easy mobility and toxicity serious threat to the ecological environment and human health seriously, therefore to search for the hydrophyte with some resistance to mercury stress was extremely urgent. The aim of the study was to investigate the influence that HgC12 under various concentrations（0, 2.5, 5.0 10.0, 20.0, 40mg·L^-1） on the growth and development of Eichhornia erassipes seedlings with hydroponics. The results indicated the FW increment, chlorophyll content, Pn value, SOD activities of Eichhornia crassipes increased first and then de- creased with the increasing of HgCl2 stress. The highest value at 5mg·L^-1, but as HgCl2 concentration increased further, these indicators continued to decline inversely. Pro and SP reached to the highest point at the 10 mg·L^-1concentration, and they continued to decline at the concentration more than 20 mg·L^-1 significantly. While Gs, Ci, Tr showed the opposite tendency compared with Pn. But it was not significant between difference HgCl2 stress. Ci, Tr reached to the highest point at the 5 mg·L^-1 concentration, but Gs at 10 mg·L^-1. The MAD content and POD activity significantly rose with the increasing of HgCl2 stress. The conclusion was that it was beneficial to Eichhornia crassipes when HgCl2 stress was below to 10mg·L^-1, meanwhile high concentration HgCl2 could be harmful to Eichhornia crassipes. The results of this research could provide a theoretical basis for exploring the adaptation mechanism of Eichhornia crassipes under HgCl2 stress.