Pedosphere 29(5): 545--553, 2019
ISSN 1002-0160/CN 32-1315/P
©2019 Soil Science Society of China
Published by Elsevier B.V. and Science Press
A Meta-Analysis on Phenotypic Variation in Cadmium Accumulation of Rice and Wheat: Implications for Food Cadmium Risk Control
LI Xiaofang1, ZHOU Dongmei2,3
1Key Laboratory of Agricultural Water Resources, Hebei Key Laboratory of Soil Ecology, The Innovative Academy of Seed Design, Centre for Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Shijiazhuang 050021(China)
2Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008(China)
3School of Environment, Nanjing University, Nanjing 210093(China)
Corresponding Author:LI Xiaofang
ABSTRACT
      In some densely-populated countries, farmland has been widely cadmium (Cd) contaminated, and the utilization of the contaminated farmland for crop production is currently unavoidable. This necessitates the use of low-Cd crops (i.e., pollution-safe cultivars, the crop varieties with the ability to accumulate a low level of Cd in their edible parts when grown on polluted soil) in these areas and highlights the importance of knowledge on phenotypic variation in crop Cd accumulation for food Cd risk control. Studies on phenotypic variation in heavy metal accumulation started decades ago for a wide range of crops, and synthesis of the scattered experimental results in the literature is in need. We built a Low-Cd Crops Database based on literature research, and relevant meta-analysis was performed to quantitatively explore the phenotypic variation in Cd uptake and translocation of rice and wheat. Considerable variability existed among rice (median grain Cd bioconcentration factor (BCF) of 0.10) and wheat (median grain Cd BCF of 0.21) phenotypes in grain Cd accumulation, and this variability was labile to soil pH and the level of Cd stress. Wheat statistically had a higher root-to-shoot Cd-translocating ability than rice, highlighting potential food Cd risks and the importance of growing low-Cd wheat in slightly Cd-contaminated regions. Meanwhile, no correlations were detected among soil-to-root, root-to-shoot, and shoot-to-grain translocation factors, implying that Cd uptake and internal translocation in crops were probably controlled by different underlying genetic mechanisms. Root-to-shoot Cd transport could be a favorable target trait for selecting and breeding low-Cd rice and wheat. In all, this review provides a comprehensive low-Cd crop list for remediation practice and a systematic meta-analysis inferring food Cd risks based on plant capacity for Cd accumulation and desired traits for low-Cd crop breeding.
Key Words:  bioconcentration factor,Cd contamination,Cd stress,heavy metal,low-Cd crops,plant uptake,pollution-safe cultivars,soil pH,translocation factor
Citation: Li X F, Zhou D M. 2019. A meta-analysis on phenotypic variation in cadmium accumulation of rice and wheat: Implications for food cadmium risk control. Pedosphere. 29(5): 545-553.
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