title: Influence of nitrogen form on the phytoextraction of cadmium by a newly discovered hyperaccumulator Carpobrotus rossii.
abstract: Using hyperaccumulator plants is an important method to remove heavy metals from contaminated land. Carpobrotus rossii, a newly found Cd hyperaccumulator, has shown potential to remediate Cd-contaminated soils. This study examined the effect of nitrogen forms on Cd phytoextraction by C. rossii. The plants were grown for 78 days in an acid soil spiked with 20 mg Cd kg(-1) and supplied with (NH4)2SO4, Ca(NO3)2, urea, and chicken manure as nitrogen (N) fertilizers. Nitrification inhibitor dicyandiamide (DCD) was applied to maintain the ammonium (NH4(+)) form. Nitrogen fertilization increased shoot biomass but decreased root biomass with the highest shoot biomass occurring in the manure treatment. Compared to the no-N control, urea application did not affect shoot Cd concentration, but increased Cd content by 17% due to shoot biomass increase. Chicken manure significantly decreased CaCl2-extractable Cd in soil, and the Cd concentration and total Cd uptake in the plant. Rhizosphere pH was the highest in the manure treatment and the lowest in the NH4(+) treatments. The manure and nitrate (NO3(-)) treatments tended to have higher rhizosphere pH than their respective bulk soil pH, whereas the opposite was observed for urea and NH4(+) treatments. Furthermore, the concentrations of extractable Cd in soil and Cd in the plant correlated negatively with rhizosphere pH. The study concludes that urea significantly enhanced the Cd phytoaccumulation by C. rossii while chicken manure decreased Cd availability in soil and thus the phytoextraction efficiency.
authors.affiliation: Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China.|Department of Animal, Plant and Soil Sciences, Centre for AgriBioscience, La Trobe University, Melbourne Campus, Bundoora, Victoria, 3086, Australia.
authors.forename: Wuxing
authors.initials: W
authors.lastname: Liu
authors.affiliation: Department of Animal, Plant and Soil Sciences, Centre for AgriBioscience, La Trobe University, Melbourne Campus, Bundoora, Victoria, 3086, Australia.
authors.forename: Chengjun
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China.
authors.forename: Pengjie
authors.initials: P
authors.lastname: Hu
authors.affiliation: Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China.|Key Laboratory of Coastal Zone Environmental Processes, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, 264003, China.
authors.forename: Yongming
authors.initials: Y
authors.lastname: Luo
authors.affiliation: Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China.
authors.forename: Longhua
authors.initials: L
authors.lastname: Wu
authors.affiliation: Department of Animal, Plant and Soil Sciences, Centre for AgriBioscience, La Trobe University, Melbourne Campus, Bundoora, Victoria, 3086, Australia.
authors.forename: Peter
authors.initials: P
authors.lastname: Sale
authors.affiliation: Department of Animal, Plant and Soil Sciences, Centre for AgriBioscience, La Trobe University, Melbourne Campus, Bundoora, Victoria, 3086, Australia. C.Tang@latrobe.edu.au.
authors.forename: Caixian
authors.initials: C
authors.lastname: Tang
mesh_terms: D035722:Aizoaceae / Q000737:chemistry / Q000378:metabolism*; D001673:Biodegradation, Environmental; D002104:Cadmium / Q000032:analysis / Q000378:metabolism*; D052918:Environmental Restoration and Remediation / Q000295:instrumentation / Q000379:methods*; D005308:Fertilizers / Q000032:analysis; D008372:Manure / Q000032:analysis; D009584:Nitrogen / Q000737:chemistry / Q000378:metabolism; D018517:Plant Roots / Q000737:chemistry / Q000378:metabolism; D012989:Soil Pollutants / Q000032:analysis / Q000378:metabolism*
chemical_list: D005308:Fertilizers; D008372:Manure; D012989:Soil Pollutants; D002104:Cadmium; D009584:Nitrogen
keywords: Ammonium (NH4–N); Animal manure; Cd; Hyperaccumulator; Nitrate (NO3–N); Phytoremediation