The Effect Of Different Temperature Treatments On Seed Germination And Seedling Physiological And Biochemical Indexes Of Ulmus Parvifolia

In this study,the seedls of Ulmus parvifolia and Ulmus parvifolia seedlings were taken as the object of study.By measuring the changes of physiological and biochemical indexes under different temperature treatments,the adaptability of Ulmus parvifolia seeds and seedlings to different temperatures was explored to provide a theoretical basis for the production and seeding of Ulmus parvifolia.The study were set to determine the germination rate,radicle length,leaf color,cell membrane permeability,osmotic adjustment substance content,resistance,chlorophyll content and other physiological and biochemical indicators.The results of the study are as follows:(1)The germination rate of Ulmus parvifolia seeds reached 54.28% at 20℃;the radicle length of seeds increased continuously with the prolonged treatment time,changes at 5℃ and 10℃ are not significantly different from other treatments.and was higher than other treatments at 20℃;relative electrical conductivity.In an upward trend,the MDA content is on the rise.Overall,the relative electrical conductivity and MDA content were lower at 20℃.The content of soluble sugar,soluble protein and free proline in the osmoregulation substances increased first and then decreased.The trend was that the osmotic adjustment substance had a small change under treatment at 20℃,and the total content was lower than other treatments,indicating that the seeds suffered less damage at 20℃;The activity of SOD,POD and CAT increased first and then decreased.The enzyme activities of SOD,POD and CAT were higher at 20℃ and CK treatment.In summary,Ulmus parvifolia the seed germination takes the longest at 20℃.(2)With the intensification of different temperature stress,leaf color browning and wilt wilting,the cell membrane permeability of loquat leaves changed,the extracellular electrolyte leakage,the membrane lipid peroxidation increased,the relative conductivity continued to increase,and the MDA content increased first and then decreased.,reached the highest at-5℃;osmoregulation of soluble sugar,proline content showed a trend of first increase and then decline,reached the highest at-10℃,soluble protein content was first decreased,then rose in a downward trend.A small peak was reached at-10℃,and the osmotic adjustment substances began to decrease at-10℃,indicating that the temperature at this time has reached the tolerance range of helium to low temperatures;The activity of SOD,POD increased first and then decreased.It reached the highest at-5℃,and the CAT activity first decreased and then rose,reaching the maximum at-5℃.High indicates that the stress resistance at this time is the strongest.The comprehensive analysis shows that-10℃ is the low temperature tolerance range of the seedlings of the Ulmus parvifolia,and the resistance exercise can be carried out early in the introduction and planting,and the adaptability of the Ulmus parvifolia to the low temperature environment can be improved.