Studies On The Physiological Responses Of Different Provenances Cercidhyllum Japoncum Under Drought Stress

Taken two-year health Cercidhyllum japoncum saplings for the test materials of three provenances(Anhui Xixian,Hu'nan Xinning,He'nan Neixiang),Hoagland nutrient solution of different configurations PEG-6000(polyethylene glycol) concentration(50 g/L,100 g/L,150 g/L,200 g/L) were used to simulating the nutrient solution under different intensity of drought stress,water stress.A comparative study of four different intensity of drought stress of leaves were Conducted in response to physiological characteristics and physiological differences,the anti-drought ability of three provenances C.japoncum were comprehensive researched and evaluated.This article was aimed to Providing a theoretical basis for drought water-saving species selection in seasonally dry areas,developing water-saving cultivation techniques,establishing monitoring systems and providing a theoretical basis route.Through the physiological measurement and analysis of C.japoncum,this study indicated the following conclusions:(1) C.japoncum,of three provenances membrane permeability increased with the stress and time that under drought stress.He'nan Neixiang C.japoncum Membrane stability was the strongest,Anhui Xixian was the second.Hu'nan Xingning was the worst.(2) Under drought stress,total leaf chlorophyll content were significantly decreased of different species of Cercidiphyllum.but differences between species is not significant(3) Three speices C.japoncum have a certain degree of osmotic adjustment ability,under drought stress,both through soluble sugar,soluble protein,proline accumulation to alleviate Stress injury to the plants.Osmotic adjustment ability were:He'nan Neixiang＞Hu'nan Xinning＞Anhui Xixian.(4) Under the drought stress,the leaves' SOD activity significantly increased to alleviate the lipid peroxidation of cell damage caused of three speices C.japoncum.During three speices,the He'nan Neixiang had the ability of the strongest that dependent on SOD to remove reactive oxygen,the weakest was the Hunan Xixian.(5) Under drought stress,MDA concentration increased with the increasing of stress and extending of time,in the end a slight decrease in its content,it showed that C.japoncum has some drought resistances and drought can not be sustained.(6) C.japoncum leaves's CAT activity increased under drought stress in PEG.with an increase in stress and time.indicating that CAT can work together with the active participation of other enzymes io remove or reduce the response to reactive oxygen species on cell damage of drought,which has a certain degree of adaptability. (7) Under the drought stress POD activity increased at first,then a downward trend in the long severe stress,that with the increase of stress time,it indicated that C.japoncum tolerance of leaf cells of the level of reactive oxygen species may be existed a threshold, over the threshold,it will lead to harm.(8) As comprehensive assessment of membership function parameters of water,during three species of C.japoncum,Anhui Xixian had the worst drought resistance,He'nan Neixiang and Hu'nan Xinning's drought resistance is closely related to stress.As a result, C.japoncum of He'nan Neixiang was the best for the seasonal drought region.If the introduction of Hunan Xinning species was needed,the relatively good irrigation area was need to be choose to meet its water needs.