The cadmium(Cd)pollution of farmland soil is serious in the world.The present study investigated the effects of intercropping Vicia faba and the hyperaccumulator Sonchus asper on the Cd accumulation and root responses...The cadmium(Cd)pollution of farmland soil is serious in the world.The present study investigated the effects of intercropping Vicia faba and the hyperaccumulator Sonchus asper on the Cd accumulation and root responses(morphology and secreted organic acids)of plants grown on soil from a mining area in Yunnan Province,China,under different Cd stress levels(0,50,100,and 200 mg kg-1).Intercropping increased the biomass of both S.asper and V.faba,as well as the Cd accumulation and Cd transfer coefficient from roots to shoots of S.asper,but decreased those of V.faba in the 200 mg kg-1Cd treatment.The Cd concentrations in roots,shoots,and grains from intercropped V.faba plants were positively correlated(P<0.05)with the N,N-diethyl phenylacetamide-extractable Cd content in soil.In the 50 mg kg-1Cd treatment,intercropping decreased citric and malic acids in root secretions of S.asper.Intercropped V.faba secreted more citric,oxalic,acetic,and malic acid compared with S.asper.Intercropping also increased root length and root surface area of both S.asper and V.faba.At 50 mg kg-1Cd,root length for S.asper was higher than that at 0 mg kg-1Cd,whereas V.faba roots had significantly decreased length and mean diameter.Intercropping of S.asper and V.faba is suggested as an in situ phytoremediation strategy of Cd-contaminated soils and may improve the food quality of V.faba.展开更多
de Longueville和Gastel(2021)提出了下述非常一般的高阶线性椭圆型方程组:△^(m)u=∑^(m-1)_(t=0)△^(l)(V_(l),du)+∑^(m-2)_(t=0)△^(l)δ(ω_(l)du),并以多调和映照方程为其典型例子.通过给系数函数以最少的光滑性假设和一阶位势的...de Longueville和Gastel(2021)提出了下述非常一般的高阶线性椭圆型方程组:△^(m)u=∑^(m-1)_(t=0)△^(l)(V_(l),du)+∑^(m-2)_(t=0)△^(l)δ(ω_(l)du),并以多调和映照方程为其典型例子.通过给系数函数以最少的光滑性假设和一阶位势的代数反对称性假设,他们成功建立了该方程组的守恒律,从而得到弱解的处处连续性,推广了Rivière(2007)及Lamm和Rivière(2008)关于2阶和4阶方程组的相应理论.最近,Guo和Xiang(2021)证明了上述方程组解的局部Holder连续性,改进了de Longueville和Gastel(2021)的连续性结果.本文使用另一种方法证明对任意的0<α<1,该方程组的弱解都是局部α-Holder连续的,进一步改进了Guo和Xiang(2021)的局部Holder连续性结果.在标准的Dirichlet边界条件下,本文还得到上述方程组弱解直到边界的连续性,推广了Guo和Xiang(2020)关于4阶方程的边界正则性结果.展开更多
基金This research was supported by the Yunnan Provin-cial Key Research and Development Project,China(No.2019BC001-04)the National Natural Science Foun-dation of China(No.41867055).
文摘The cadmium(Cd)pollution of farmland soil is serious in the world.The present study investigated the effects of intercropping Vicia faba and the hyperaccumulator Sonchus asper on the Cd accumulation and root responses(morphology and secreted organic acids)of plants grown on soil from a mining area in Yunnan Province,China,under different Cd stress levels(0,50,100,and 200 mg kg-1).Intercropping increased the biomass of both S.asper and V.faba,as well as the Cd accumulation and Cd transfer coefficient from roots to shoots of S.asper,but decreased those of V.faba in the 200 mg kg-1Cd treatment.The Cd concentrations in roots,shoots,and grains from intercropped V.faba plants were positively correlated(P<0.05)with the N,N-diethyl phenylacetamide-extractable Cd content in soil.In the 50 mg kg-1Cd treatment,intercropping decreased citric and malic acids in root secretions of S.asper.Intercropped V.faba secreted more citric,oxalic,acetic,and malic acid compared with S.asper.Intercropping also increased root length and root surface area of both S.asper and V.faba.At 50 mg kg-1Cd,root length for S.asper was higher than that at 0 mg kg-1Cd,whereas V.faba roots had significantly decreased length and mean diameter.Intercropping of S.asper and V.faba is suggested as an in situ phytoremediation strategy of Cd-contaminated soils and may improve the food quality of V.faba.
