Abstract:To explore the role of exogenous BR on the induced resistance of cucumber seedlings to Ca(NO3)2 stress,we determined the effects of different treatments of exogenous BR (0.01 mg·L-1 BR soaking seeds,0.1 mg·L-1 BR spraying leaves and combination of both) on growth,physiological indexes,and photosynthetic characteristics of cucumber seedlings under 60 mmol·L-1 Ca(NO3)2 stress in this paper.The result indicated that:(1)the exogenous BR significantly increased the height,stem diameter,number of expand leaves,leaf area,contents of proline and soluble sugar of cucumber seedlings and decreased the content of MDA,activity of POD increased,promoted the photosynthesis rate,transpiration rate and stomatal conductance of cucumber seedlings and inhibited the increase of intercellular CO2 concentration.(2)BR soaking seeds and spraying leaves with suitable concentration of exogenous BR could effectively enhance the cucumber seedlings osmotic adjustment capacity,reduce membrane peroxidation damage,improve antioxidant enzyme activity and photosynthetic efficiency,thus showing Ca(NO3)2 stress resistance,and the treatment of 0.01 mg·L-1 BR soaking seeds showed the best results.
