Protective Role of Selenium on Development and Physiological Responses of Vicia faba

Abstract

Monocarpic senescence of faba bean (Vicia faba L.) has been studied, but no information is available on the impact of selenium on physiological activities associated with senescence in this crop. The investigation was undertaken to determine how pretreating seeds with selenium affected growth and development and factors affecting senescence in faba bean. Seeds were treated with selenium (0, 25, 50, and 100 mg^.L⁻¹) for 20 h. One-month-old seedlings of faba bean, cv. Giza 3, were placed in the dark to induce senescence-like changes. Selenium treatment ameliorated adverse effects of induced senescence by increasing activity of antioxidant enzymes such as catalase (EC 1.11.1.6) and peroxidase (EC 1.11.1.7) and also chlorophyll content, total protein, free amino acids, photosynthetic efficiency (¹⁴CO₂-fixation), and activities of ribulose-1,5-bisphosphate-carboxylase/oxygenase (rubisco, EC 4.1.1.39) and nitrate reductase (EC 1.7.99.4) compared to controls. Retention of more leaf area, with better partitioning efficiency, appeared to contribute to increased 100 seed weight and total yield/plant in plants treated with selenium. Treatment at 50 mg·L⁻¹ of selenium decreased H₂O₂ content of plants compared to controls. Selenium at 50 mg·L⁻¹ increased transpiration rate of plants compared to controls but had no effect at 25 and 100 mg·L⁻¹. Pretreatment of faba bean seed with selenium at 50 mg·L⁻¹ may contribute to delayed leaf senescence and improved total yield.

Keywords:

• Antioxidant
• ¹⁴CO₂-fixation
• Enzymes
• Oxidative stress
• Rubisco
• Senescence