摘要
在处理污水的潜流人工湿地中,湿地植物容易受到缺氧胁迫.尽管菖蒲(Acorus calamus L.)是一类对缺氧条件具有显著抵抗能力的湿地植物,但菖蒲的生理响应并不能完全消除湿地长期缺氧带来的胁迫.生物炭添加能够缓解菖蒲体内超氧化物和过氧化物的积累,显著降低膜脂过氧化程度,但生物炭对缓解缺氧胁迫的具体机制尚不清晰.因此,本研究通过在温室内构建5种不同的生物炭湿地,采用植物生态学分析方法,将植物根系通气组织、根孔隙度和根系泌氧相结合,研究菖蒲根部组织对生物炭添加的响应机制.结果表明,通过在传统潜流人工湿地中添加生物炭,有利于菖蒲形成根系通气组织,增大根孔隙度,生物炭投加量与根孔隙度具有显著正相关关系.在湿地中添加生物炭将利于O_2通过通气组织传输至地下部分,并以根系泌氧(radial oxygen loss,ROL)的形式扩散至根际,显著提高根系泌氧量.与其它光强相比,在3 000μmol·(m^2·s)^(-1)条件下,菖蒲泌氧能力较强,生物炭投加比例对植物ROL的影响不显著.
In the subsurface flow of a constructed wetland(CW)used for treating wastewater,low oxygen diffusion results in long-term anoxic or anaerobic surroundings,which cannot meet the needs of plant respiration and poses a threat to the survival of macrophytes.Although sweet sedge(Acorus calamus L.)has a significant ability to resist hypoxia,membrane lipid oxidation would still occur in the plant due to the long-term hypoxia in the CW.According to reports in the existing literature,activation of the antioxidative response system could be promoted by adding biochar,thereby significantly decreasing the malonic dialdehyde in the plants.However,the specific reasons why biochar alleviates the stress from anoxia are still not clear.Thus,the responses of macrophyte roots to biochar application were studied in five different CWs built in a greenhouse,using plant ecology analyses combined with root aerenchyma,root porosity,and radial oxygen loss(ROL).The results showed that adding biochar to CW was beneficial for sweet sedge to form root aerenchyma and to increase root porosity.Moreover,there was a significant positive correlation between root porosity and the amount of biochar applied.Photosynthetic metabolism could be indirectly promoted by biochar application by increasing oxygen partial pressure in the blades,helping to transport O2 to underground parts through aerenchyma,and spreading O2 to the rhizosphere in the form of ROL.The reduction environment could be improved by applying biochar in CWs,which was also beneficial for ROL.Compared with other light conditions,3 000μmol·(m2·s)-1 was more suitable for the growth of A.calamus in CWs with biochar,where the ability of the plants to secrete oxygen would be stimulated and enhanced.However,the effect of the biochar application ratio on ROL was not significant.
作者
黄磊
梁银坤
梁岩
罗星
陈玉成
HUANG Lei;LIANG Yin-kun;LIANG Yan;LUO Xing;CHEN Yu-cheng(College of Resources and Environment,Southwest University,Chongqing 400715,China;Chongqing Engineering Research Center of Rural Cleaning,Chongqing 400716,China)
出处
《环境科学》
EI
CAS
CSCD
北大核心
2019年第3期1280-1286,共7页
Environmental Science
基金
国家自然科学基金项目(51408493)
重庆市基础与前沿研究计划项目(cstc2016jcyjA0523)
关键词
生物炭
潜流人工湿地
菖蒲
根系通气组织
根系泌氧(ROL)
biochar
subsurface flow constructed wetland
Acorus calamus L.
root aerenchyma
radial oxygen loss(ROL)
