Moderate Mn accumulation enhances growth and alters leaf hormone contents in the hyperaccumulator Celosia argentea Linn.

Abstract To better understand the unique concentration–response relationship in hyperaccumulators, the effects of manganese (Mn) accumulation on the growth of Celosia argentea Linn., a Mn hyperaccumulator, were investigated using hydroponic experiments. Manganese accumulation (8860–14200 mg/kg in leaves) is toxic to most plants but beneficial to the growth of C. argentea. The C. argentea root length and root surface area at Mn supply concentrations of 20 and 40 mg/L were significantly higher than those at 0.5 mg/L (control treatment). Leaf number and leaf area were 24 % and 66 % greater, respectively, at 20 mg Mn/L than at the control concentration. Moderate Mn accumulation (8860–14200 mg/kg) significantly increased plant dry weight (p