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EDTA-INDUCED Improvement in GROWTH AND water relationS of sunflower (Helianthus annuus L.) PLANTS grown in lead contaminated medium

Nazila Azhar¹, Muhammad Yasin Ashraf^2*, Mumtaz Hussain¹, Muhammad Ashraf¹ and Rashid Ahmed³

Abstract:

A sand culture experiment was carried out to examine whether EDTA applied through the rooting medium could mitigate the injurious effects of Pb on growth and water relations in two sunflower hybrids (H-33 and H- 64A93). Eight Pb and EDTA levels i.e., 0, 1 and 2 mM Pb(NO₃)_2,  1 and 1.5 mM EDTA and the combinations of Pb and EDTA as 1 + 1, 1+ 1.5 and  2 + 1.5  [mM Pb (NO₃)₂  + EDTA, respectively] with three replications were maintained during the course of study. Water relations parameters i.e., leaf water potential (Y_W), solute potential (Y_S), turgor potential (Y_P) and relative water contents (RWC) were estimated after 40 days of exposure to Pb & EDTA level and thereafter plants were harvested and their shoot and root dry weights recorded. Applications of either Pb or EDTA decreased shoot and root dry mass of both sunflower hybrids. However, application of  1 + 1 mM Pb + EDTA was effective in maintaining higher shoot dry weight, but for the root dry weight, 1 + 1.5 mM Pb + EDTA treatment was more effective than the others. The sunflower hybrid H-33 performed better than H-64A93 under Pb, EDTA and Pb + EDTA treatments. Relative water contents (RWC); Y_W, Y_S, and Y_P decreased with increase in Pb or EDTA levels, however, addition of EDTA to the Pb contaminated medium was found to be beneficial in increasing the RWC and  Y_P necessary for sustaining  plant growth and productivity under normal and stress conditions. Sunflower hybrid H-33 maintained higher Y_P and RWC than those of H-64A93. Overall, addition of EDTA to Pb contaminated medium was found beneficial in improving the plant water relations and growth in the two sunflower hybrids used in this study.

¹Department of Botany, University of Agriculture, Faisalabad, Pakistan.

^2*Plant Stress Physiology Lab., Nuclear Institute for Agriculture and Biology (NIAB), Jhang Road, Faisalabad, Pakistan (niabmyashraf@gmail.com)

³Department of Crop Physiology, University of Agriculture, Faisalabad, Pakistan.