生物炭溶解性炭黑对植物根系分泌物光毒性的影响

Biochar is used in ecological environment remediation, climate change and agricultural soil improvement. Dissolved black carbon participate in the formation of natural organic matter. Plants use dissolved organic matter as nutrients and provide nutrients to plants through the absorption of plant roots. However, there is a lack of analysis and discussion on other environmental chemical processes caused by biochar application, such as the effect of plant rhizosphere environment. Plant survival in a particular rhizosphere requires sensing changes in the local environment and responding adaptively. During exposed to pests and diseases, plants root exudates respond to strong fluorescence responses under ultraviolet radiation, and resulting in the insecticidal and bactericidal defense responses of plants. Dissolved black carbon is a highly reactive component in water environment, and it can participate in the reaction process. We should pay more attention to the effect of dissolved black carbon on plants root in the study of the photochemical activity of dissolved black carbon. .In this project, we are going to study the effect of dissolved carbon black on the phototoxicity of plant root exudates for the first time. We suppose the high photochemical activity of dissolved carbon black under sunlight exposure may reduce the fluorescence toxicity of root exudates. The effects of dissolved carbon black on the phototoxicity of root exudates will be studied. The culture and identification of rhizosphere bacteria will be conducted and then the growth of bacteria, degradation kinetics of root exudates and binding coefficients of dissolved carbon black and root exudates in experiment system will be determined. The reactive oxygen species in the reaction system were captured and determined. In the end, the fluorescence of plants root exudates and the degradation pathway and degradation products of root exudates will also be analyzed. This study will provide more comprehensive and reliable information and data support for the environmental impact analysis and risk assessment of biochar.

生物炭主要应用于生态环境修复、气候变化和农业土壤改良等方面。有关施用生物炭对农作物影响的表观研究中显示，生物炭在一定程度上能提高农作物的产量。但是，针对施用生物炭引起的其他环境化学过程，例如对植物根际环境的影响，却缺乏相关机理的分析讨论。在本项目中我们首次针对溶解性炭黑对植物根系分泌物光毒性的影响进行研究，通过根系分泌物的荧光分析，植物根际细菌的培养、鉴定，开展溶解性炭黑对根系分泌物光毒性影响的实验；测定实验中根系分泌物的降解动力学，分析体系中植物根系分泌物降解途径以及降解产物；观测实验过程中细菌的生长状况，对反应体系中的活性氧进行捕捉测定，测定溶解性炭黑与根系分泌物的结合系数，对溶解性炭黑对植物根系分泌物光毒性的影响进行分析。项目旨在为生物炭的环境效应分析和风险评估提供更加全面可靠的信息和数据支持。

生物炭经生物质和化石燃料不完全燃烧产生，溶解性炭黑是水环境中反应活性较高的组分，可以参与水环境中的反应过程。溶解性炭黑具有很强的光催化降解污染物的能力。在光照作用下溶解性炭黑能够诱导形成活性氧ROS，例如羟基自由基（·OH）、单线态氧（1O 2）、超氧阴离子（O2-）和过氧化氢（H2O2）。本项目针对生物炭溶解性炭黑光照条件下产生ROS的化学结构进行了深层识别和探究，并对溶解性炭黑光照条件下生成ROS降解抗生素的过程展开研究，证明了溶解性炭黑与抗生素之间的相互作用对抗生素的光降解过程存在抑制。本研究项目的研究结果，推进了天然水体中溶解性有机制光照条件下产生的ROS的机理过程研究，清晰地识别出具体的含氧官能团结构，对ROS生成的具体路径过程。为有关天然有机质光照条件下产生ROS的机理过程分析提供了更为深入全面的分析视角。另外，本项目研究中首次采用的针对光敏性有机污染物在溶解性有机质参与过程中，溶解性有机质对污染物去除浓度贡献的计算方法，可以应用推广到相关的光敏性有机污染物光催化降解研究过程中，为有机污染物的环境风险和行为研究提供了更加清晰准确的研究方法。