title: Use of low-calcium cultivars to reduce cadmium uptake and accumulation in edible amaranth (Amaranthus mangostanus L.).
abstract: This study aimed to investigate the mechanism of low Cd accumulation in crops using edible amaranth (Amaranthus mangostanus L.) as a model. Fifteen amaranth cultivars were grown in long-term contaminated soil, and the differences in soil Cd mobilization, root uptake, and root-shoot translocation between low- and high-Cd accumulating cultivars were examined. The transport pathways of Cd across the root were further identified in Hoagland nutrient solution using the Ca channel blocker La3+, the ATP inhibitor 2, 4-dinitrophenol (DNP), and a nutrition-deficient culture. Cd concentrations in amaranth cultivars varied about six-fold and showed an elevated trend as the concentration of Ca and Zn increased (p < 0.01), but did not exhibit any correlation with Mg and Fe. The concentrations of essential metals (Ca, Mg, Zn, and Fe) in the rhizosphere of low-Cd cultivars were significantly lower than those of high-Cd cultivars, and decreased with decreasing levels of soluble rhizosphere exudates. These findings indicated that low co-mobilization of Cd with essential metals mediated by root-induced exudates of low-Cd cultivars contributed to its low accumulation in amaranth. Uptake of Cd was inhibited along with Ca by La3+and DNP, but was promoted by Ca or Fe deficiency treatment. Therefore, the Ca pathway is likely the mode of Cd entry into amaranth roots, although Zn and Fe transporters may also be involved. Low-Ca cultivars exhibited lower Cd uptake capability than high-Ca cultivars. The low translocation efficiency of Cd from root to shoot also contributed to its low content accumulation in edible parts of amaranth.
authors.affiliation: School of Environment and Guangzhou Key Laboratory of Environmental Exposure and Health, Jinan University, Guangzhou, 510632, China; Department of Ecology, Jinan University, Guangzhou, 510632, China.
authors.forename: Bao-Yan
authors.initials: BY
authors.lastname: He
authors.affiliation: School of Environment and Guangzhou Key Laboratory of Environmental Exposure and Health, Jinan University, Guangzhou, 510632, China.
authors.forename: Dan-Ping
authors.initials: DP
authors.lastname: Yu
authors.affiliation: School of Environment and Guangzhou Key Laboratory of Environmental Exposure and Health, Jinan University, Guangzhou, 510632, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Chen
authors.affiliation: School of Environment and Guangzhou Key Laboratory of Environmental Exposure and Health, Jinan University, Guangzhou, 510632, China.
authors.forename: Jia-Li
authors.initials: JL
authors.lastname: Shi
authors.affiliation: School of Environment and Guangzhou Key Laboratory of Environmental Exposure and Health, Jinan University, Guangzhou, 510632, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Xia
authors.affiliation: School of Environment and Guangzhou Key Laboratory of Environmental Exposure and Health, Jinan University, Guangzhou, 510632, China; Guangdong Provincial Research Center for Environment Pollution Control and Remediation Materials, Guangzhou, 510632, China. Electronic address: liqusheng@21cn.com.
authors.forename: Qu-Sheng
authors.initials: QS
authors.lastname: Li
authors.affiliation: School of Environment and Guangzhou Key Laboratory of Environmental Exposure and Health, Jinan University, Guangzhou, 510632, China; Guangdong Provincial Research Center for Environment Pollution Control and Remediation Materials, Guangzhou, 510632, China.
authors.forename: Li-Li
authors.initials: LL
authors.lastname: Wang
authors.affiliation: School of Environment and Guangzhou Key Laboratory of Environmental Exposure and Health, Jinan University, Guangzhou, 510632, China.
authors.forename: Ling
authors.initials: L
authors.lastname: Ling
authors.affiliation: School of Environment and Guangzhou Key Laboratory of Environmental Exposure and Health, Jinan University, Guangzhou, 510632, China.
authors.forename: Eddy Y
authors.initials: EY
authors.lastname: Zeng
mesh_terms: D027721:Amaranthus / Q000378:metabolism*; D002104:Cadmium / Q000378:metabolism*; D002118:Calcium; D018556:Crops, Agricultural / Q000378:metabolism; D018517:Plant Roots / Q000378:metabolism; D018520:Plant Shoots / Q000378:metabolism; D010945:Plants, Edible / Q000378:metabolism; D058441:Rhizosphere; D012989:Soil Pollutants / Q000378:metabolism*
chemical_list: D012989:Soil Pollutants; D002104:Cadmium; D002118:Calcium
keywords: Ca-deficient culture; Low accumulation; Rhizosphere exudates; Translocation; Transport pathway