The effect of cysteine amino acid to gaining resistance in barley (Hordeum vulgare L.) against to boron toxicity

In this study, it is aimed to investigate the healing effects of cysteine amino acid on the barley plant exposed to boron toxicity. To this end, sensitive species (Reyhan) of barley (Hordeum vulgare L.) to boron stress was chosen. Boron stress level and concentrations of cysteine to be used in this process were determined as 5 mM for boron and 200 μM for cysteine as preliminary trials. Growth parameters (root and stem lengths), dry matter content, total soluble protein and carbohydrate, proline, MDA, the amount of reactive oxygen species (ROT) (hydroxyl ion (OH-), hydrogen peroxide (H2O2), superoxide (O2.¯)) and enzymatic antioxidants (superoxide dismutase (SOD), catalase (CAT), peroxidase (POD) and ascorbate peroxidase (APX) activity and non-enzymatic antioxidants (ascorbate (AsA), dehydro ascorbate (DHA) and glutathione (GSH)) quantities have been examined comparatively in barley plants growing in control, boron stress (B) and boron+ cysteine (B+S) conditions. Root and stem lengths decreased significantly in the boron stress were increased with the cysteine application. While boron stress was increased total sugar, protein, proline, oxidants (O2.-, H2O2 ve OH-), MDA amounts, SOD, APX and POD activities, decreased CAT activity in both roots and stem. Because of Boron + Cysteine application cause improvements in all of these parameters, it has been suggested that cysteine can be used as a reliable chemical in the recovery of boron stress in the barley.