Study of the effects of 24-epibrassinolide and water stress on some physiological parameters in canola (Brassica napus L.) seedling

Brassinosteroids are phytohormones possessing a wide spectrum of antistress activity. The effects of 24-epibrassinolise on leaf water content، leaf area، lipid peroxidation، electrolyte leakage، protein content and ethylene production were investigated in canola (Brassica napus L. cv. Fusia) seedling under water stress. The seeds were sown in plastic pots containing sand، clay and peat (in proportion of 1:1: 1). Solution of 24-epi-brassinolid at 10-7 M concentration containing 0. 01% Tween-20 (polyoxyethylene sorbitan) was sprayed on leaves at intervals of 1، 2 and 3 weeks after sowing. Control plants were sprayed with 0. 01% Tween-20. One month after sowing، plants were harvested. Lipid peroxidation level and electrolyte leakage significantly increased under water stress but decreased when 24-epibrassinolid were applied، revealing that less oxidative damage occurred in this group. Protein content، water content and ethylene production was decreased when 24-epibrassinolide were applied even under water stress and was higher than control plants. Leaf area was significantly decreased under water stress but 24-epibrassinolide had no appreciable effect on the leaf area. Results suggested that، 24-epibrassinolide can considerably alleviate oxidative damage induced by water stress conditions.