摘要
以挺水景观植物梭鱼草（Pontederia cordata L.）为对象,通过室内培养试验,研究了不同质量浓度NH4^＋-N下低质量浓度微囊藻毒素-LR（MC-LR）对梭鱼草叶片谷胱甘肽系统的影响。结果表明,在试验设置的质量浓度（1μg/L、10μg/L、30μg/L）范围内,MC-LR对梭鱼草叶片谷胱甘肽系统具有显著影响,尤其以30μg/L影响效果最为显著。具体表现为：暴露8 d时,叶片中谷胱甘肽S-转移酶（GST）、谷胱甘肽过氧化酶（GPX）及谷胱甘肽还原酶（GR）活性都显著增加;而暴露20 d时,MC-LR对叶片谷胱甘肽系统表现出抑制效应,GSH质量比、GSH/GSSG比值及GST、GPX、GR活性都显著下降,叶片中MC-LR质量比增加,导致谷胱甘肽氧化还原系统被破坏。而在试验设置的NH4^＋-N质量浓度（1 mg/L、3 mg/L、6 mg/L）范围内,NH4^＋-N质量浓度升高对梭鱼草抵御MC-LR胁迫有积极的作用。具体表现为：NH4^＋-N质量浓度升高能够提高并维持梭鱼草叶片谷胱甘肽系统各相关酶类活性,有助于GSH质量比及GSH/GSSG比值保持相对稳定。因此,低浓度MC-LR在暴露一定时间后仍然会对梭鱼草产生胁迫影响,而富营养化水体中较高浓度的NH4^＋-N对于梭鱼草的恢复具有明显的促进作用。
The present paper is inclined to make an evaluation of the low concentrated MC - LR on the glutathione system of the leaves of P. cordata L. , an emergent landscape plant, through the indoor cultivation experiments under the effects of different NH4＋ - N concentrations. The results of our cultivation experi- ments indicate that, MC - LR is in a position to make a signifi- cant effect on the glutathione system through the leaves of P. cordata L. with its greatest significant effect being 30 p.g/L within the range of the concentrations known as 1 1.μg/L, 10 μg/L, 30 μg/L set up in the experiment. More exactly speaking, the activ- ities of glutathione-S-transferase （ GST）, the glutathione peroxi- dase （GPX） and the glutathione reductase （GR） have been found increased significantly 8 d later since its application. Nevertheless, beyond 20 days, or, as we say, 20 days later, the said MC - LR tends to demonstrate inhibitive effect on the glutathione system. What is more, with the increase of the GSH content and the ratio of GSI4/GSSG, the activities of GST, GPX and GR would begin to show a declining trend, and, later on, the MC - LR content in the leaves may result in shrinking and deterioration of the glutathione redox system of the leaves themselves. Furthermore, it has also been detected that, in the range of NH-＋ - N concentration （1 mg/L, 3 mg/L, 6 mg/L） set up in the experi-ment, the elevated concentrations of NH4＋ - N turns out to show a positive effect on the resistance of P. cordata L. to MC - LR＇ s stress. Thus, it becomes clear that, when MC - LR is of 30 -L, the GSH content, the GSH/GSSG ratio, and the GST and GR activities in the leaves of P. cordata L. may all tend to increase significantly with the increase of the concentration of NH4＋ - N for the period of 20 days. However, with the increase of the concentrations of NH＋ - N, the activities of GST and GPX in the leaves of P. cordata L. beyond 20 days would have no more significant i,ffluence on the activities. Even, beyond the said 8 days, we can find that higher concentration of NH4＋ - N would fail to bring any significant improvement up to the said activities, rather, to keep merely up the activities of the enzymes related to the glutathione system to ensure the GSH content and GSH/GSSG ratio to keep on the stable and regular activities more or less relatively. Thus, it can be said that low concentrations of MC - LR may still keep up the coercive effect on P. cordata L. through a definite exposure for a certain period, with the higher concentrations of NH4＋ - N in the eutrophic water bodies, given a significant promotion to the recovery of P. cordata L..
作者
陈国元
陈颖
白铭贤
李振东
游伊
CHEN Guo-yuan;CHEN Ying;BAI Ming-xian;LI Zhen-dong;YOU Yi(College of Environment Science and Engineering,Xiamen University of Technology,Xiamen 361024,Fujian,China)
出处
《安全与环境学报》
CAS
CSCD
北大核心
2018年第5期1963-1970,共8页
Journal of Safety and Environment
基金
福建省自然科学基金项目(2017J01491)
