Enhancement drought tolerance of sugar beet (Beta vulgaris L.) in vitro by sodium azide

Abstract

Drought represents the most significant environmental challenge impacting the sugar beet growth and productivity. Sodium azide (NaN3) is relatively safe to handle and the most efficient mutagen. So, the objective of the present investigation was to study the effect of presoaking two sugar beet cultivars seeds in various concentrations of sodium azide to improve drought tolerance in vitro. Results showed that the polyethylene glycol (PEG) at 5% or 10% caused water stress in medium and lead to highly significant reduction in shoot length, fresh weight, leaves number and photosynthetic pigment (Chl a, b and car). The 10% of PEG-6000 recorded the maximum reduction in growth parameter of two studied sugar beet cultivars. Otherwise, the tested sodium azide treatments improved sugar beet growth under stressed and unstressed plants. Presoaking of sugar beet seeds in 8 mM of sodium azide raises the shoot length, fresh weight, number of leaves and photosynthetic pigment of two cultivars and the most raising reported at unstressed plants. Proline content and antioxidant enzymes (POD, SOD and CAT) increased with increasing in poly ethylene glycol concentration. Moreover, sodium azide triggers the highest production of antioxidants enzymes in two cultivars of sugar beet under drought stress. Finally, presoaking of seeds in 4 or 8 mM of sodium azide can be enhancing drought tolerance in sugar beet.