Influence of different soaking times with selenium on growth, metabolic activities of wheat seedlings under low temperature stress

Abstract

Low temperature (LT) is one of the most important factors limiting the growth, development and distribution of wheat plants in temperate regions. Selenium often acts as an antioxidant in plants and this study  hypothesize that selenium application can partly alleviate LT-induced oxidative stress and negative impacts of LT on wheat (Triticum aestivum L.) plant. Wheat seeds were soaked in aqueous solutions of selenium (5 mg Se L^–1) for 5, 10 and 15 h. Then, the seeds were germinated at 3 or 5°C for 14 days and allowed to recover at 22°C for three days. The results show that low temperature stress inhibited the growth, chlorophylls, soluble sugars and antioxidant enzyme activities and increased oxidant production and membrane damage. Soaking the seeds in selenium solution for different times was feasible in enhancing the growth, chlorophylls,  anthocyanin, sugars, proline contents and enzymatic activities and decreased membrane damage by  enhancing antioxidant defense coupled with the appearance of novel protein bands. Se induced the lowering of respiratory potential measured as electron transport system (ETS) activity of mitochondria. However,  prolonged soaking in selenium (15 h) exerts toxic effects. These positive effects of Se are, however, dependent on the period of soaking.

Key words: Selenium, cold stress, wheat seedlings, antioxidants, protein electrophoresis, respiratory potential.