Study On The Physiological Response Of Salt Stress And Drought Stress Of Bambusa Tuldoides Cv.swolleninternode

Bambusa tuldoides cv.Swolleninternode is a fine kind of bamboo on green landscape.At present,as the increasing scope of landscaping,it is inevitable to plant in the soil salinization and arid and semi arid areas.Therefore,the salt stress and drought stress of Bambusa tuldoides cv.Swolleninternode were studied on physiological responses under stress,the results would be for the application of bamboo drum to promote the theoretical basis.In this study,salt stress was treated with concentration of salt as followed 0.3%,0.6%,0.9%,1.2%and 1.5%and the drought stress was studied by method of natural drought stress to measure relative water content,chlorophyll(SOD,POD,CAT)activity,soluble protein,proline and malondialdehyde of bamboo leaves under different stress conditions.The main results were as followed:(1)The morphological characteristics of Bambusa tuldoides cv.Swolleninternode were significantly different with the salt concentration and the stress time under the salt stress.The higher the concentration,the curl of the leaves was more severe.The relative water content of the leaves except 0.3%,the rest of the concentration of treatment were a downward trend,and the higher the salt concentration decreased greatly.(2)The chlorophyll a,chlorophyll b and chlorophyll(a + b)of the Bambusa tuldoides cv.Swolleninternode decreased with the stress time under the salt stress,and the chlorophyll a was more sensitive than chlorophyll b,and the chlorophyll a/increased with stress time and salt concentration,the ratio increased,and the concentration was higher,the greater rise;and the conten of chlorophyllt decreased slowly and have seen a much smaller drop under the salt concentration was 0.9%.(3)The activity of superoxide dismutase(SOD),peroxidase(POD)and catalase(CAT)in the leaves of Bambusa tuldoides cv.Swolleninternode treated with different salt concentrations showed a trend of increasing firstly and then decreasing,of which 0.6%and 0.9%concentration of SOD activity reached the maximum at the 18th day of stress;and the other treatments of POD and CAT were also peaked maximun on the 12th day.The three enzymes coordinate with each other,so that the peak time were different.The activity of protective enzymes in different treatments showed decreased after 18 days of stress,indicated that the bamboo shoots under salt stress could resist salt damage by increasing the activity of protective enzymes,but increased with stress concentration,they protective effect of cells gradually weakened.(4)The contents of soluble protein in Bambusa tuldoides cv.Swolleninternode increased firstly and then decreased with different stress concentration and time,and the salt concentration was 1.2%and 1.5%reached the maximum at the 12th day,and the salt concentration was 0.6%and 0.9%which reached the maximum at the 18th day;but 0.3%concentration and control compared that there was no difference,which was slowly rising.The content of prolline also reached the maximum at the concentration of 1.2%and 1.5%when the 12th day,0.9%reached the maximum at the 18th day,and the salt concentration of 0.3%and 0.6%showed a slow increasing trend.While the salt concentration of 1.2%and 1.5%of the treatment of proline content began to decline on the 18th day of stress,and the higher concentration,the more significantly decline.(5)The concentration of malondialdehyde(MDA)in the salt treatment group increased with stress time,and the higher the salt concentration,the greater the increase of MDA.Bambusa tuldoides cv.Swolleninternode cell membrane was destroyed later of salt stress,so that the extravasation of MDA was exacerbated.(6)Bambusa tuldoides cv.Swolleninternode had a certain salt tolerance,which could withstand the highest salt concentration was 0.9%.(7)Under the natural drought stress,the appearance of Bambusa tuldoides cv.Swolleninternode changed obviously.With the increase of stress days,the leaves of the bamboo shoots were withered and dried,and some bamboo poles were gradually yellowed.With the increase of stress days,the water content of bamboo leaves decreased continuously,and showed a sharp decline on the 18th day of stress.(8)Under drought stress,the contents of chlorophyll a,chlorophyll b and chlorophyll(a + b)were decreased gradually with the increase of time,and decreased to the lowest at the end of stress while chlorophyll a/b was increased,and rised to the highest level at the end of the stress.(9)Under drought stress,the activities of SOD,POD,CAT and other protective enzymes increased firstly and then decreased with stress time.The activity of SOD and POD increased to the maximum at the 12th day,CAT reached maximum on the 18th stress day.The peak time of these three enzymes were different and coordinated.(10)The content of soluble protein increased with the increase of drought stress,reached the maximum at the 6th day,and then decreased slowly.The content of proline increased with the increase of time,and then decreased rapidly after reaching the maximum value on the 12th day.While the content of malondialdehyde(MDA)increased with the increase of drought time.With the increase of drought stress,the damage of Bambusa tuldoides cv.Swolleninternode was seriously serious,and various protective mechanisms gradually lost the function of protection in the body.(11)The results of variance analysis showed that there were significant differences in physiological indexes among different treatments(P<0.01).Compared with malondialdehyde(MDA),the relative water content,chlorophyll content,protective enzyme activity and proline(Pro)were negatively correlated with soil water content,MDA and SOD were significantly negative There was a significant positive correlation between leaf water content and chlorophyll content.MDA and soluble protein were correlated negatively.(12)Bambusa tuldoides cv.Swolleninternode had a certain drought tolerance,which could tolerate the maximum extent of drought for the soil water content was 3.9%.