title: Synergetic effects of DA-6/GA₃ with EDTA on plant growth, extraction and detoxification of Cd by Lolium perenne.
abstract: Research is needed to improve efficiency of phytoextraction of heavy metals from contaminated soils. A pot experiment was carried out to study the effects of plant growth regulators (PGRs) (diethyl aminoethyl hexanoate (C18H33NO8, DA-6) and gibberellic acid 3 (C19H22O6, GA3)) and/or EDTA on Cd extraction, subcellular distribution and chemical forms in Lolium perenne. The addition of EDTA or PGRs significantly enhanced Cd extraction efficiency (P<0.05), with the decreasing order of: 1 μM DA-6>10 μM DA-6>10 μM GA3>2.5 mmol kg(-1) EDTA>other treatments of PGR alone. PGRs+EDTA resulted in a further increase in Cd extraction efficiency, with EDTA+1 μM DA-6 being the most efficient. At the subcellular level, about 44-57% of Cd was soluble fraction, 18-44% in cell walls, and 12-25% in cellular organelles fraction. Chemical speciation analysis showed that 40-54% of Cd was NaCl extractable, 7-23% HAc extractable, followed by other fractions. EDTA increased the proportions of Cd in soluble and cellular organelles fraction, as well as the metal migration in shoot; therefore, the toxicity to plant increased and plant growth was inhibited. Conversely, PGRs fixed more Cd in cell walls and reduced Cd migration in shoot; thus, metal toxicity was reduced. In addition, PGRs promoted plant biomass growth significantly (P<0.05), with 1 μM DA-6 being the most effective. A combination of DA-6/GA3 with EDTA can alleviate the adverse effect of EDTA on plant growth, and the treatment of EDTA+1 μM DA-6 appears to be optimal for improving the remediation efficiency of L. perenne for Cd contaminated soil.
authors.affiliation: College of Environmental Science and Engineering, Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, Zhejiang Gongshang University, Hangzhou, Zhejiang, China. Electronic address: heshanying2007@gmail.com.
authors.forename: Shanying
authors.initials: S
authors.lastname: He
authors.affiliation: College of Environmental Science and Engineering, Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, Zhejiang Gongshang University, Hangzhou, Zhejiang, China. Electronic address: wql27@126.com.
authors.forename: Qiuling
authors.initials: Q
authors.lastname: Wu
authors.affiliation: Indian River Research and Education Center, Institute of Food and Agricultural Sciences, University of Florida, Fort Pierce, FL 34945, USA. Electronic address: zhe@ufl.edu.
authors.forename: Zhenli
authors.initials: Z
authors.lastname: He
mesh_terms: D002104:Cadmium / Q000378:metabolism*; D002208:Caproates / Q000378:metabolism*; D004357:Drug Synergism; D004492:Edetic Acid / Q000378:metabolism*; D005875:Gibberellins / Q000378:metabolism*; D007854:Lead / Q000378:metabolism*; D008129:Lolium / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D012989:Soil Pollutants / Q000378:metabolism*
chemical_list: D002208:Caproates; D005875:Gibberellins; D012989:Soil Pollutants; C572218:diethyl aminoethyl hexanoate; D002104:Cadmium; D007854:Lead; D004492:Edetic Acid; C007842:gibberellic acid
keywords: Cd extraction; Detoxification mechanism; EDTA; L. perenne; Plant growth regulators