Evaluation of cereal response to stress generated by heavy metals: de-termination of physiological and biochemical modifications, and antiox-idative defense of Hordeum vulgare L. against lead

Abstract

The persistent nature of heavy metals makes them hazardous in long term. The use of natural chelation by tolerant plants remains a more rational and promising way for the environment compared to the use of chemical chela-tors. Barley has already been used as a model plant in the case of heavy met-als pollution.The present study focuses on the effect of lead at different con-centrations (100mg/l, 500mg/l and 900mg/l) on barley Hordem vulgare L. After 30 days of growth, the plants were harvested and physio-biochemical parameters (fresh weight, length, relative water content, photosynthetic pigments, hydrogen peroxide, lipid peroxidation, total protein and activity of catalase and peroxidase) were studied in both leaves and roots. Results re-vealed that lead induced a decrease in fresh weight, length, relative water content and photosynthetic pigments in lead treated plants compared to the control, while an increase was recorded in lipid peroxidation, hydrogen per-oxide production and protein content, the enhancement in the activity of antioxidant enzymes (catalase and peroxidase), revealed the capacity of bar-ley to react to stress caused by lead, indeed the antioxidant enzymes consti-tute among others, a way to protect the plant against oxidative stress in-duced by lead, furthermore the antioxidant enzymes are part of the toler-ance mechanisms used by plants against heavy metals, however the dosage of lead in the different parts of the plant remains essential because it could highlight a possible phytoextraction of lead by barley.