Effects of fertilization and exogenous arsenic on resistance physiology and growth of pak-choi

A pot experiment was conducted to study the effects of different fertilizers and concentrations of arsenic on plant height, root length, fresh weight, As content, proline (Pro.) content, malondialdehyde (MDA) content, and superoxide dismutase (SOD) and peroxidase (POD) activities of pak-choi (Brassica campestris L. ssp. Chinensis L.). The results show that the arsenic fertilization stimulateds the growth of pak-choi at the concentration of 10 mg/kg under the fertilization treatments, the fresh weight per plant of pak-choi is the highest and the plant height and root length are increased. But the growth of pak-choi is inhibited, as exogenous arsenic concentration is increased. The arsenic contents of pak-choi plant are increased with the increase of the exogenous arsenic concentration, and the fertilization is also increased the content of arsenic in pak-choi plant. The contents of Pro and MDA in pak-choi plant are all increased with the increase of the exogenous arsenic concentration, while those are decreased in fertilization treatments. The activity of POD in pak-choi changes with a pattern of up-down, as exogenous arsenic increased, and is highest at the arsenic concentration of 50 mg/kg in no-fertilizer treatment, and is increased in the fertilization treatments. The activity of SOD in pak-choi is increased, as exogenous arsenic concentration increased in the organic fertilizer treatment, and changes with a pattern of up-down and is highest at the arsenic concentration of 50 mg/kg in the treatments of no-fertilizer, NPK fertilizers, and NPK fertilizers mixed with organic fertilizer.