Chromosome doubling of Sedum alfredii Hance: A novel approach for improving phytoremediation efficiency

Sedum alfredii Hance is a cadmium (Cd)/zinc (Zn) hyperaccumulator native to China. However, its relatively low biomass restricted the large-scale application for heavy metal contamination remediation. The chromosome set doubling of S. alfredii in vitro was achieved by 0.1%-0.2% (W/V) colchicine treatment. The plant DNA ploidy was analyzed by flow cytometry and chromosome set doubling plants (CSD) were identified based on the obvious different sharp peak. A tissue culture experiment with different Cd treated levels and a field trial with natural polluted mined soil were conducted to study the effects of chromosome doubling on plant biomass and Cd accumulation in shoots. The results suggested that S. alfredii is a mixoploid. Compared with the wild type plants (WT), CSD exhibited typical gigas characteristics in morphology including stem thickness, root hair production, number of leaves and size of stoma guard cell. Fresh weight and dry weight of CSD were increased to 1.62-2.03-fold and 2.26-3.25-fold of WT. And Cd content of CSD showed a 17.49%-42.82% increase and 59% increase under tissue culture and field condition, accordingly. In addition, the TF and in BCF of CSD were 2.37- and 1.59-fold of WT, respectively. These results proved that it is feasible to promote phytoextraction efficiency of S. alfredii in Cd contaminated soils through chromosomal engineering, which provides a novel approach for hyperaccumulator application in phytoremediation. (c) 2019 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V.