Zirconium induced physiological alterations in wheat seedlings

Abstract

The effects of zirconium ascorbate (Zr-ASC), a water-soluble complex of Zr, were examined on wheat seedlings (Triticum aestivum L. cv. MV. 20). Hydroponically grown plants were exposed to 10, 33, 55, 100 and 550 μM Zr-ASC (Zr10, Zr33 etc.). After 9 d of treatment inhibition of germination, retarded root and shoot growth, and increased activities of antioxidant enzymes (guaiacol peroxidase, ascorbate peroxidase, and glutathione reductase) showed that Zr-ASC was only harmful at and over a concentration limit of 100 μM. Chlorophyll (Chl) content of plants was only decreased by Zr 550. Zr-ASC at lower concentrations was beneficial for plant development: Zr10 and Zr33 enhanced root elongation, Zr55 induced about 30 % increase in the total Chl content, while the activity of antioxidant enzymes was not elevated indicating that no oxidative stress was generated by the intracellularly accumulated Zr4+ ions.