EXOGENOUSLY APPLIED GLYCINEBETAINE ALLEVIATES CHROMIUM TOXICITY IN PEA BY REDUCING CR UPTAKE AND IMPROVING ANTIOXIDANT DEFENSE SYSTEM

Abstract

Soils with chromium (Cr) pollution are significantly increasing globally. Therefore, proper measures should be opted for to restrict its entry into food crops. Glycinebetaine (GB)-induced tolerance in plants against different abiotic stresses has been well documented, but still little evidence is available concerning its potential to increase the tolerance of pea against Cr stress. Therefore, this study determined the impact of GB application in increasing Cr tolerance in pea (Pisum sativum). The experiment was comprised of three concentrations of Cr (0 mM, 0.25 mM, and 0.50 mM) and two levels of foliar-applied GB (0 and 50 mM). Chromium stress led to a significant reduction in growth, biomass production, and photosynthetic pigments however, Cr stress increased reactive oxygen species (ROS) production. Exogenously applied GB reduced the deleterious impacts of Cr stress on pea and increased growth, biomass production, and photosynthetic pigments. Moreover, GB reduced ROS production and Cr accumulation in plant roots and shoots by increasing the activities of antioxidant enzymes (APX, CAT, POD and SOD) and consequently increased growth and plant biomass production. In conclusion, beneficial effects of GB under Cr stress were attributed to reduced Cr uptake, enhanced photosynthetic pigment and enzymatic activities and less ROS production.