Genotypic screening of wheat and their physiological responses under lead toxicity

Abstract

Lead (Pb) is the second most harmful heavy metal contaminant in the environment and toxic for plant growth and development. Therefore, the identification and selection of plant genotypes tolerant to Pb stress are of great significance. In this study, twenty-six wheat lines (Triticum aestivum) were screened for Pb tolerance based on their morpho-physiological variations at the seedling stage with a rapid hydroponic technique using lead nitrate (Pb(NO3)2) at two concentrations (500 μM and 1 mM) along with control. Wheat genotypes showed distinct variations in plant height, plant biomass and chlorophyll concentration in response to different concentrations of Pb. Considering all parameters, Akbar was found most tolerant (T) with minimum RS (2.97) to Pb stress, followed by BARI Gom-31 (3.45), Barkat (3.54) and Sufi (3.65), while BARI Gom-26 (10.14) was most sensitive (S) followed by Khude Gom (9.69), BARI Gom-30 (8.79), LalGom (8.76) and BARI Gom-32 respectively. More scores were seen in the remaining genotypes and were graded as moderately tolerant/resistant (MT) to Pb stress. Results showed that the resistant line had less damage to root and shoot characteristics along with chlorophyll score, thereby providing a hint about the Pb tolerance capacity of wheat genotypes at the seedling stage. Furthermore, findings indicate that Pb susceptibility in wheat is predominantly associated with a decrease in the Pb components of the root and shoot. We suggest Akbar as an elite genotype to cultivate or use in downstream studies on the basis of our findings to ensure an improved crop production relative to other varieties evaluated. These findings provide the necessary background for Pb cleansing and Pb-free wheat development for environment and health safety.