Chromium (VI) induced phytotoxicity and oxidative stress in pea (Pisum sativum L.): biochemical changes and translocation of essential nutrients.

Due to widespread industrial use, chromium (Cr) is considered a hazardous environmental pollutant. It is known to inhibit plant growth and development. The present study provides the evidence of the phytotoxicity of this metal on the pea (Pisum sativum L. cv Azad) plants. The plants of pea (Pisum sativum L.) were grown in refined sand under different concentrations i.e. 0.05, 0.1, 0.2, 0.3 and 0.4 mM of Cr (VI) in order to study the effect on growth and yield, photosynthetic pigments, relative water content, non-reducing sugar and protein with activity of certain enzymes like catalase, peroxidase, starch phosphorylase and ribonuclease. The analysis of the results showed that photosynthetic pigments (68.68%), relative water contents (62.77%), non-reducing sugar (66.66%) and protein (81.57%) were decrease along with reduction in plant height (52.69%) and leaf area (50.81%) of the pea plants. However, in response to various concentration of Cr exposed plants showed significant induction of reducing and total sugars with enzymes like catalase, starch phosphorylase and ribonuclease. The translocation of Cr in various part of pea plant have been found in order of root> stem> leaves>seeds which ranged between 34.8 to 217.3 mg g(-1) d.wt. (dry weight) in roots, 6.5 to 173.13 mg g(-1) d.wt. in shoot, 4.2 to 74.43 mg g(-1) d.wt. in leaves and 0.94 to 8.64 mg g(-1) d.wt. in seeds, that is also reflected by the transfer factor of Cr from refined sand to tested species.