Effects of 24-epibrassinolide on lipid peroxidation, prolin, sugar and photosynthesis pigments content of colza(Brassica napus L.) under water stress

Brassinosteroids are a new class of plant hormones with unique biological effects on plant growth and development. Brassinosteroids also can increase plant tolerance for water stress. The effects of 24-epibrasinolide on lipid peroxidation and content of proline, soluble sugars, chlorophyll and carotenoids were investigated in Colza (Brassica napus L. cv. Fusia) plant under water stress. The seeds were sown in plastic pots containing sand, clay and peat (in proportion of 1:1:1). Solution of 24-epibrassinolid 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 significantly increased under water stress but decreased when 24-epibrassinolid were applied, revealing that less oxidative damage occurred in this group. Proline and carotenoids content was decreased when 24- epibrassinolide were applied even under water stress and was higher than control plants. Chlorophyll content was significantly decreased under water stress but increased by 24- epibrassinolide application. Additionally, the soluble sugar content of 24- epibrassinolide-treated plant under water stress was lower than well-watered plant under the same treatment. Results suggested that, 24-epibrassinolide can considerably alleviate oxidative damage induced by water stress conditions.