Effect Of Brassinolide On Tomato Seedlings Under Drought Stress

Drought stress damage to crops has caused widespread concern, many researchers through different ways and methods to improve the drought resistance of plants, great progress has been achieved in this time. The existing research shows that spraying BRASSINOLIDE have effectively improve crop drought resistance, relieve the damage of plants under drought stress. But enhance the BR signal is to improve drought resistance of plants is poorly understood. Therefore, this study use tomato Micro-Tom as materials, setting five concentrations with 2,4 Epibrassinolide, screened the optimum concentration of Brassinolide to improve drought resistant of tomato seedlings. Then choose the optimum concentrations to spraying tomato Micro-Tom, and compared with BRI1 overexpressing transgenic plants under drought stress. The main results are:(1)Under drought stress,0.1μM 2,4-Epibrassinolide spraying tomato’s shoot dry and fresh weight,proline content,soluble sugar content,the activity of protective enzymes is the highest than other concentration(0,0.01,0.5,1μM).Therefore,spraying 0.1μM 2,4-Epibrassinolide is the optimum concentration of tomato seedlings under drought stress.(2)Under drought stress, spraying 2,4 Epibrassinolide(0.1μM),tomato leaves proline content,activity of protective enzymes were significantly higher than SlBRI1 overexpressing line,but the accumulation of H2O2 lower.(3)Under drought stress,spraying 2,4 Epibrassinolide(0.1μM) tomato’s net photosynthetic rate(Photo),intercellular CO2 concentration(Ci),stomatal conductance(Cond),transpiration rate decreases more slowly than SlBRI1 overexpressing line.(4)Under drought stress, spraying 2,4 Epibrassinolide(0.1μM) tomato’s Fv/Fm,Fv’/Fm’,φPS Ⅱ,qP,F0 significantly higher than SlBRI1 overexpressing line,and NPQ significantly lower than SlBRI1 overexpressing line.Thus,Compared with the BR signaling pathway to enhance,improve the level of BR can improve drought resistance of tomato seedlings.The SlBRI1 overexpressing line was more sensitive to drought stress.