Effects Of Exogenous Abscisic Acid And Brassinolide On Photosynthetic Characteristics In Syringa Oblata Under Water Stress

The occurrence of water stress is harmful to the growth and development of plants.In recent years,because of the changing environment,the harm is more significant.The exogenous hormones abscisic acid(ABA)and brassinolide(BR)have a certain effect on the water stress resistance of plant.Syringa oblata has a variety of resistance and strong adaptability to environment,usually used in Heilongjiang province and indispensable landscaping species,it has good environmental value and medicinal value,but it has a less characteristics to flooding resistance.Therefore in this paper,we took Syringa oblata seedlings as the experimental materials,processed by different concentration of exogenous hormone,in order to find the suitable concentration,so as to provide theoretical basis and practical reference to improve the resistance of Syringa oblata.Under drought stress,applied exogenous ABA and BR on Syringa oblata.leaves decreased the relative conductivity,the difference between each treatment is not obvious,membrane damage reduction,slow down the degradation of chlorophyll,high concentration of BR had a certain inhibition,the high content of chlorophyll,made high photosynthetic efficiency increase and maintain a high level;after rewatering,the chlorophyll content increased,the relative conductivity decreased,photosynthetic and fluorescence recovery,when treated ABA with BR,the recovery of rewatering was better in the late drought.In conclusion,BR treatment alone,0.2mg�L-1 is more appropriate,when common treatment,the most suitable concentration is 2mg�L-1 ABA plus 0.4mg�L-1 BR,relieving the drought stress in Syringa oblata.,the influence of drought persecution on the growth and development of Syringa oblata.was reduced,and a certain extent,other indexes such as photosynthesis efficiency were enhanced,which enhanced the drought resistance of Syringa oblata.Syringa oblata.under waterlogging stress,all the indexes showed a downward trend,but there were still leaves in the late flooding stage;Relative conductivity increased,especially the treatment with ABA,the physiological function of ABA promotes abscission and promotes senescence,photosynthetic and fluorescence related indexes decreased obviously,there still had weak photosynthesis in the late flooding,indicating that BR could improve the waterlogging resistance of Syringa oblata.,but ABA had little effect on relieving waterlogging stress.To sum up,the optimal concentration of BR treatment in the 0.2~0.4mg�L-1,which could improve the resistance to waterlogging.