Lead toxicity affects growth and biochemical content in various genotypes of barley (Hordeum vulgare L.)

Lead is a widely spread environmental pollutant and its concentration is dramatically increasing in our ecosystems. Jordan is facing this significant problem because of the dramatic increase in population size, especially due to the crisis of Syrian refugees. In this study, nine barleys (Hordeum vulgare L.) genotypes (two cultivars and seven landraces) were grown under controlled growth conditions, and checked for their tolerance responses against two levels of lead nitrate (0 and 7 mM) in terms of growth (germination, shoot and root length) and biochemical (proline content and lipid peroxidation) responses. Genetic variation between barley landraces was also assessed using ISSR-PCR and results indicated genetic variability among the studied barley landraces. A toxic effect of lead on seed germination, root and shoot systems for all tested genotypes coupled with alterations in biochemical content were observed. LR4 and LR5 showed high growth rates, high proline content and low MDA level compared to the rest of genotypes. Therefore, LR4 and LR5 might be the most appropriate genotypes to be used in future breeding programs to produce lead-tolerant barley cultivars.