Journal of Environmental Biology

Response of wheat seed germination and seedling growth under copper stress

 Dharam Singh, Kamlesh Nath and Yogesh Kumar Sharma*

Department of Botany, University of Lucknow, Lucknow-226 007, India

(Received: May 25, 2005 ; Revised received: November 01, 2005 ; Accepted: January 25, 2006)

Abstract: The experiment was performed to study the seed germination and seedling growth in wheat under the influence of different concentrations of copper. The germination %, plumule and radicle length, and number of lateral roots decreased with increase in copper concentration (5, 25, 50 and 100 mgl^-1). Total chlorophyll contents declined on 14^th day from 1.605 of control to 1.581, 1.242, 1.275 and 1.107 mg g^-1 fresh weight in respective treatments. Similarly, on 21^st day the decline in total chlorophyll contents was 1.288, 1.123, 1.077 and 0.985 mg g^-1 fresh weight in respective treatments against 1.724 of control. Likewise the pheophytin contents also declined showing the same pattern. However, carotenoid contents increased in different treatments, ranging between 0.366 to 0.464 mg g^-1 fresh weight in comparison to control (0.328) on 14^th day, but showed adverse effects on 21^st day as the carotenoid contents decreased in different copper treatments. The activity of amylase was found to be gradually reduced 14^th day from 29.73 of control to 27.80, 27.33, 21.86 and 20.00 mg g^-1 and at 21^st day from 14.40 of control to 11.46, 11.01, 9.86 and 5.60 mg g^-1  fresh weight with increase in concentrations of copper. The catalase activity increased 14^th day from 97.33 of control to 134.66, 161.33, 216.00 and 232.00  and on 21^st day from 140.00 of control to 245.33, 274.66, 278.66 and 300.66 ml H₂O₂ hydrolyzed/g fresh weight in different increased concentrations of copper. Similarly, the peroxidase activity was also increased with increase in copper concentration. Likewise fresh weight and moisture contents decreased with increase in copper concentration. The dry weight was increased with increase in concentration of copper treatment. Total protein contents were initially decreased on 14^th day from 80.69 of control to 66.75, 60.41, 56.41 and 48.48 mg/mg  and on 21^st day 81.37 of control to 67.06, 62.31, 54.92 and 46.47 mg/mg fresh weight in different copper concentrations respectively. Sugar contents were significantly decreased in all the doses of copper on both 14^th and 21^st days i.e. (5.53 of control to 4.76, 3.69, 3.68 and 2.86 mg/mg in different copper treatments on 14^th day and  4.81 of control to 4.49, 3.40, 2.79 and 2.15 mg/mg on 21^st day respectively.

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