Cadmium, a high toxic heavy metal, is one of the most serious contaminants in soil and a potential threat to plant growth and human health. Amino acid metabolism has the central role in heavy metal stress resistance of plants. In this paper, a pot experiment was carried out to study the effects of different concentrations of cadmium (0, 3, 6, 12, 30 mg kg(-1)) on the growth, Cd accumulation and amino acid metabolism in two Compositae plants (Ageratum conyzoides L. and Crassocephalwn crepidioides). The results showed that under cadmium stress, C. crepidioides accumulated more Cd in its shoot and was tolerant to Cd, whereas its low Cd-accumulating relative, A. conyzoides, suffered reduced growth. The Cd content in the aerial part of C. crepidioides exceeded the threshold of Cd-hyperaccumulator. Furthermore, the bioaccumulation factor (BCF) and biological transfer factor (BTF) values for Cd in C. crepidioides were > 1. Thus, C. crepidioides can be regarded as Cd-hyperaccumulator. The comparison between both studied plants indicated that Cd stress resulted in a differential but coordinated response of amino acid levels, which are playing a significant role in plant adaptation to Cd stress. Glu, Gln, Asp, Asn, Gaba, Val and Ala dominated the major amino acids. Higher Cd tolerance and Cd accumulation in C. crepidioides was associated with greater accumulation of free amino acids, especially for Gln and Asn, in C. crepidioides than in A. conyzoides. Publication name | ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY, 158 300-308; 10.1016/j.ecoenv.2018.04.045 AUG 30 2018 | Author(s) | Zhu, Guangxu; Xiao, Huayun; Guo, Qingjun; Zhang, Zhongyi; Zhao, Jingjing; Yang, Dan | Corresponding author(s) | ZHU Guangxu1,2;XIAO Huayun1,3 zhugx.10b@igsnrr.ac.cn; xiaohuayun@vip.skleg.cn 1.Chinese Acad Sci, Inst Geochem, State Key Lab Environm Geochem, Guiyang 550081, Guizhou, Peoples R China 2.Guiyang Univ, Coll Biol & Environm Engn, Guiyang 550005, Guizhou, Peoples R China 3.China Univ Technol, Key Lab Nucl Resource & Environm, Lab Atmospher Environm, Nanchang 330013, Jiangxi, Peoples R China | View here for the details
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