Effects of three metal ions on growth and physio-biochemical response of Achnatherum inebrians

The effects of manganese (Mn), zinc (Zn) and iron (Fe) on growth parameters of drunken horse grass (Achnatherum inebrians) over an 8-week period were determined with controlled-environment experiment. Varions were also determined for anti-oxidative enzymes including catalase (CAT), superoxide dismutase (SOD) and peroxidase (POD), proline and malonialdehyde (MDA). The results showed that the plant height, tiller number and aboveground biomass of A.inebrians decreased with the increasing concentration of Mn, Zn and Fe, which had significant differences (P0.05) among treatments. However, MDA and the proline content significantly (P0.05) increased with the increasing concentration of heavy metals. Under the stress of Mn, POD activities of A. inebrians increased with the increasing concentration of Mn. CAT and SOD activities significantly (P0.05) increased under the concentrations of 0.01～2.5 mmol·L-1 treatments and dropped dramatically under the concentrations of 2.5～7.5 mmol·L-1 treatments. Under the stress of Zn, POD activities had a peak value at 7.0 mmol·L-1, while SOD activities maintained higher level at 14.0 mmol·L-1 treatment which had significant (P0.05) difference with other concentrations treatments. Under the stress of Fe, POD activities significantly (P0.05) increased with the increasing concentrations of Fe and SOD and CAT activities had a peak value at 6.0 mmol·L-1 which had significant (P0.05) difference. These results suggested that the A.inebrians had strong tolerance to three heavy metal stresses, as reflected by morphological parameters and reduced ROS injury.