EFFECT OF LEAD TOXICITY ON GROWTH, DEVELOPMENT AND YIELD OF RICE

Abstract

Lead toxicity adversely affects the growth and development of rice plants. An experiment was carried out to evaluate the effect of lead (Pb) stress on morphological, physiological and yield performance of rice plant (Oryza sativa L. cv. BRRI dhan29 and cv. BRRI dhan58). The experiment was carried out at the net house of the Department of Agricultural Botany and Plant Physiology Laboratory of Sher-e-Bangla Agricultural University, Dhaka, Bangladesh in Boro season during the period from December, 2020 to May 2021. To know the effects of different lead levels on the morphological, physiological and yield performance of rice plant. The double factor experiment was laid out in a randomized complete block design (RCBD) with three replications and the differences between the means were evaluated by Least Significant Difference (LSD). In this experiment, the treatments consisted of control and three different lead levels viz. Pb 0 = without lead (0 mM PbSO 4 , Lead(II) sulfate), Pb 1 = 2 mM PbSO 4 , Pb 2 = 4 mM PbSO 4 , Pb 3 = 6 mM PbSO 4 and two different variety viz. V 1 = BRRI dhan29, V 2 = BRRI dhan58. The lead treatments were applied at 15 days after transplanting (DAT). The results showed that the no. of non-effective tillers, proline content, no. of unfilled spikelets panicle -1 increased under Pb toxicity. Lead stress decreased the morphological parameters (plant height, no. of tillers, leaf area) and the values of physiological (MSI%, RWC%, SPAD value, dry weights) attributes in both rice cultivars. Root, shoot, leaf dry weights, and TDM also decreased in both rice cultivars under Pb stress. Yield attributes (panicle length, no. of effective, no. of filled and 1000 grain wt.) and yield (grain yield) parameters were reduced significantly (P ≤ 0.05) under lead stress condition. The loss of grain yield for rice variety 1/BRRI dhan29 due to Pb 1, Pb 2 and Pb 3 level of lead was 15.43%, 35.24% and 48.72% respectively over non-lead stressed control. The loss of grain yield for rice variety 2/BRRI dhan58 due to Pb 1, Pb 2 and Pb 3 level of lead was 11.82%, 26.88% and 39.02% respectively over nonlead

stressed control. Therefore, it can be concluded Pb-induced toxic effect on morphological and physiological parameters can cause substantial damage of different rice cultivars which can adversely affect yield attributes of rice plant that ultimately decrease the yield of different rice cultivars.