摘要
为探究沉水植物与镧改性粘土组合技术中植物根系对沉积物磷释放控制的作用,本研究构建了苦草-镧改性凹土(LMA)原位控磷微宇宙实验,利用薄膜扩散梯度(DGT)、高分辨率间隙水采样(HR-Peeper)和16S rRNA测序等技术,系统分析了根际磷和微环境的动态变化.结果表明,与单独覆盖LMA相比,LMA与苦草的联合应用使沉积物-间隙水中溶解反应性磷(SRP)、DGT-labile P和活性磷(Mobile-P)的含量分别下降了12.16%~62.72%、33.33%~38.46%和3.66%~10.53%.从第7d至第45d,苦草根系的总长度、表面积、体积、根尖数及有机酸分泌量显著增加.根系分泌的氧气分别使沉积物-水界面的溶解氧浓度和氧渗透深度增加了1.16倍和3.42倍,驱动根际微生物中优势菌群由Thiobacillus等溶磷菌向Sideroxydans等好氧菌转变.Mantel test和偏最小二乘路径模型(PL-PM)分析进一步揭示,苦草根系分泌的有机酸加速了沉积物中OP的矿化,增强了苦草对OP的吸收利用.此外,苦草根系释放的氧气促进了铁氧化菌的增殖,将间隙水中的Fe^(2+)持续氧化为Fe3+,使SRP以铁结合态磷(Fe-P)的形式被固定,从而有效抑制了间隙水中磷的释放.本研究为深入理解镧改性粘土与沉水植物联合控制富营养化湖泊内源磷释放的机制提供了新视角.
In this study,microcosm experiment containing Vallisneria spiralis and La-modified attapulgite(LMA)was conducted to investigate the role of submerged macrophytes roots in controlling sediment phosphorus(P)release through the combined application of submerged macrophytes and La-modified clay.The dynamic variations of rhizosphere P and microenvironment were systematically analyzed using diffusive gradients in thin films(DGT),high-resolution dialysis(HR-Peeper),and 16S rRNA amplicon sequencing techniques.The results showed that the combined application of LMA and Vallisneria spiralis reduced the concentrations of soluble reactive P(SRP),DGT-labile P,and mobile forms of P(Mobile-P)in the sediment-porewater by 12.16%to 62.72%,33.33%to 38.46%,and 3.66%to 10.53%,respectively,compared to the sole use of LMA.From day 7to day 45,significant increases were observed in the total length,surface area,volume,root tip numbers and organic acid secretion of Vallisneria spiralis roots.Root-release oxygen enhanced the dissolved oxygen concentration and oxygen penetration depth at the sediment-water interface by 1.16-fold and 3.42-fold,respectively,shifting the dominant rhizosphere microbial communities from P-solubilizing bacteria such as Thiobacillus to aerobic bacteria such as Sideroxydans.Mantel test and partial least squares path modeling(PL-PM)analysis further revealed that organic acids secreted by Vallisneria spiralis roots accelerated the mineralization of organic P in the sediment,thereby enhancing OP absorption and utilization by the roots.Additionally,root-released oxygen promoted the proliferation of iron-oxidizing bacteria,which continuously oxidizing Fe^(2+)to Fe3+in the porewater.This process immobilized SRP in the form of iron-bound P(Fe-P),effectively inhibiting P release from the porewater.This study provides novel insights that deepen the understanding of the mechanisms through which La-modified clay and submerged macrophytes jointly regulate the release of endogenous P in eutrophic lakes.
作者
韩天伦
王万忠
鲍美君
梁思嘉
刘晨飞
李建
王燕
孔明
HAN Tian-lun;WANG Wan-zhong;BAO Mei-jun;LIANG Si-jia;LIU Chen-fei;LI Jian;WANG Yan;KONG Ming(Nanjing Institute of Environmental Sciences,Ministry of Ecology and Environment,Nanjing 210042,China;Nanjing Water Science Institute Ruidi Technology Group Co.,Ltd,Nanjing 210003,China)
出处
《中国环境科学》
北大核心
2025年第8期4501-4512,共12页
China Environmental Science
基金
中央级公益性科研院所基本科研业务费专项资金资助项目(GYZX230306)
生态环境部南京环境科学研究所创新团队项目(ZX2023QT017)。
关键词
沉积物磷
镧改性粘土
沉水植物
根际效应
微生物作用
sediment phosphorus
La-modified clay
submerged plants
rhizosphere effect
microbial action
