摘要
通过3组水培试验研究了营养液不同供硼(B)浓度和叶面施B对水稻(Oryza sativa L.)幼苗吸收、转运和分泌砷(As)的影响.在10μmol·L-1三价砷[As(Ⅲ)]或五价砷[As(Ⅴ)]处理下,营养液B浓度没有显著影响水稻体内As(Ⅲ)、As(Ⅴ)和总As的含量、转移系数和根吸收效率.叶面施B使得水稻幼苗地上部的B含量显著增加15.8倍,使得As(Ⅴ)处理条件下的根部As含量和As根吸收效率分别显著降低20.9%和18.0%,As(Ⅲ)处理条件下的根部As含量和As根吸收效率分别降低12.6%和13.8%(P<0.05),而地上部As含量降低不显著(P>0.05).在As(Ⅴ)处理下,叶面施B使根部B含量显著降低达47.1%,而As(Ⅲ)处理下根部B含量无显著变化.As(Ⅴ)处理下的水稻根部B含量平均比As(Ⅲ)处理高85.3%(P<0.05).叶面施B后,As(Ⅴ)处理下水稻根部中总As含量和As(Ⅴ)含量均与根部B含量呈显著正相关(P<0.05).As(Ⅲ)预处理后水稻幼苗根系外泌的As总量比As(Ⅴ)预处理高105.2%.叶面施B使As(Ⅲ)预处理水稻的As外泌量增加14.0%~16.9%(P>0.05),对As(Ⅴ)预处理的水稻As外泌无影响.水稻根部有45.9%~70.7%的As可以在1周内被外排到生长介质中.结果表明,营养液供B浓度为As浓度的4倍时仍不能减少水稻幼苗对As的吸收累积,而叶面施B有助于减少水稻对As的吸收.B通道不是As(Ⅲ)进入水稻根系的主要途径;As(Ⅴ)在水稻中的迁移分配机制可能与B的迁移运输有关.
The impacts of boron( B) root application and foliar spray on arsenic( As) uptake,translocation,and efflux by/in rice seedlings( Oryza sativa L.) were investigated in three hydroponic experiments. The addition of B to culture medium did not alter concentrations of arsenite( As[Ⅲ]),arsenate( As[Ⅴ]),and total As,nor did it alter transfer coefficients or uptake efficiency of As in rice seedlings under either As( Ⅲ) or As( Ⅴ) exposure. Foliar B supply increased shoot B concentrations 15. 8-fold,and decreased root As concentrations and As uptake efficiency by 20. 9% and 18. 0% under As( Ⅴ) treatment,and by 12. 6% and 13. 8% under As( Ⅲ) treatment,respectively,yet did not significantly decrease shoot As concentrations( P〈0. 05). Interestingly,foliar B supply reduced root B concentrations by up to 47. 1% under exposure to As( Ⅴ) but not As( Ⅲ),and corresponding root B concentrations were 85. 3% higher in As( Ⅴ) treatment than in As( Ⅲ) treatment on average( P〈0. 05). Both total As and As( Ⅴ) concentrations were positively related to B concentration in rice roots under As( Ⅴ) treatment following foliar B supply( P〈0. 05). Rice seedlings extruded 105. 2% more As after As( Ⅲ)-pretreatment than after As( Ⅴ)-pretreatment. Foliar B supply increased the amount of As excreted by As( Ⅲ)-pretreated rice root by 14. 0%-16. 9%( P〈0. 05),and had no effect on the As efflux of As( Ⅴ)-pretreatment seedlings. A range of 45. 9%-70. 7% of root As was excreted to solution during one week. These results indicate that the root application of B at four times the concentration of As can slightly decrease As accumulation by rice,whereas foliar B supply is conducive to a decline in As acquisition by rice roots. It is likely that the B channel is at least not the main pathway for As( Ⅲ)entering into rice roots,and the As( Ⅴ) distribution mechanism in rice plants may be shared with that of B.
作者
朱毅
孙国新
陈正
胡莹
郑瑞伦
ZHU Yi;SUN Guo-xin;CHEN Zheng;HU Ying;ZHENG Rui-lun(Beijing Research & Development Center for Grasses and Environment, Beijing Academy of Agriculture and Forestry Seienees Beijing 100097, China;State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environment Sciences Chinese Academy of Sciences, Beijing 100085, China;Department of Environmental Science, Xi'an Jiaotong-Liverpool University Suzhou 215123, China)
出处
《环境科学》
EI
CAS
CSCD
北大核心
2018年第7期3400-3408,共9页
Environmental Science
基金
国家自然科学基金项目(41501336)
北京市优秀人才培养资助项目(2015000020060G141)
北京市农林科学院科技创新能力建设专项(KJCX20170411)
关键词
三价砷
五价砷
硼
外泌
吸收
水稻
arsenite
arsenate
boron
efflux
uptake
rice