复合改良剂强化博落回修复锰矿渣的机理

Mechanism of compound modifiers strengthening Macleaya cordata to remediate manganese slag

【目的】植物修复是重金属污染土壤修复的有效策略,添加改良剂有利于提高植物修复效果。本研究利用前期试验筛选出的复合改良剂(蘑菇渣和凹凸棒)联合博落回植物修复锰矿渣。【方法】以锰矿渣为基质进行盆栽试验,测定锰矿渣改良条件下博落回的叶绿素含量、抗氧化系统、亚细胞分布、化学形态、微观结构和官能团,揭示复合改良剂(蘑菇渣和凹凸棒)对锰矿渣植物修复的影响。【结果】复合改良剂的加入可以提高矿渣渗透性和肥力,改善博落回的生长条件,促进了博落回的生长。改良条件下,叶绿素的含量显著增加,光合效率明显提升;叶片中的超氧化物歧化酶(SOD)和过氧化物歧化酶(POD)活性显著增加,通过去除了过量的ROS,调节渗透压,降低脂质过氧化程度,从而使叶片对Mn胁迫的耐受性增强。改良矿渣中博落回通过增加水提取态Mn^(2+),促使大部分Mn^(2+)与有机酸结合解毒,毒害减少。透射电镜观察到改良矿渣中的博落回根、茎、叶细胞结构完整。此外,博落回通过功能基团(-CH3和-COOH)将Mn结合在细胞壁和液泡中来降低Mn对博落回细胞的损伤水平。【结论】博落回是一种能有效稳定锰矿渣重金属元素的草本植物。复合改良剂(蘑菇渣和凹凸棒)对锰矿渣的改良,降低了锰对博落回的毒性,提高了植物修复效果。

【Objective】Phytoremediation is an effective strategy for the remediation of heavy metal contaminated soil.Adding amendments is beneficial to improve the effect of phytoremediation.In this study,the compound modifiers(mushroom dregs and attapulgite)selected from the previous experiment were used in combination with Macleaya cordata to restore manganese slag.【Method】A pot experiment was carried out with manganese slag as the substrate,to determine the chlorophyll content,antioxidant system,subcellular distribution,chemical forms,microstructure and functional groups of Macleaya cordata under the modified conditions of manganese slag,and reveal the impact of the compound modifiers(mushroom dregs and attapulgite)on the phytoremediation of manganese slag.【Results】The addition of compound modifiers can improve the permeability and fertility of the slag,improve the growth conditions and promote the growth of Macleaya cordata.Under the improved conditions,the content of chlorophyll was significantly increased,and the photosynthetic efficiency was significantly improved.The activities of superoxide dismutase(SOD)and superoxide dismutase(POD)in leaves were significantly increased.By removing the excessive ROS,the osmotic pressure was adjusted and the degree of lipid peroxidation was reduced,therefore the tolerance of leaves to manganese stress was enhanced.In the improved slag,by increasing the amount of Mn^(2+)extracted by water solutions,the majority of Mn^(2+)was combined with organic acids to detoxify.Via transmission electron microscopy,it was showed that the root,stem,and leaf cells of Macleaya cordata in the modified slag were intact.In addition,Macleaya cordata used functional groups(-CH3 and-COOH)to incorporate manganese into the cell wall and vacuole to reduce the level of manganese-induced damage to the cytoplasmic cells.【Conclusion】Macleaya cordata is a herb that can effectively stabilize the heavy metal elements of manganese slag.The modification of manganese slag by compound modifiers(mushroom dregs and attapulgite)reduces the toxicity of manganese to Macleaya cordata and improves the phytoremediation effect.