Physiological Response Characteristics Of Secale Cereale Lolium To Freezing-thawing And Acid Deposition

Freezing-thawing phenomenon is due to seasonal or day and night temperature changes in the soil repeated freezing-melting processed.The change of environment caused by the freezing-thawing process exerted a series of direct or indirect effect on plant growth and development,makes the morphological characteristics and physiological functions of vegetation has formed special adaptability.Acid deposition refers to the process by which the acidic substances in the atmosphere migrate mainly to the surface by means of precipitation.Acid deposition stress had severe adverse influence on plant growth and development,it has become one of the global environmental pollution problems.The research object in this paper is Secale Cereale Lolium.By setting three adverse situations such as simulation freezing-thawing,simulation acid deposition.The physiological response characteristics of freezing-thawing and acid deposition stresses to Secale Cereale Lolium were systematically studied.To provided a theoretical basis for the further study of the adaptability of pasture and turfgrass to cold weather and adversity environment.The main results are as follows:1.Simulation freezing-thawing test: As temperature changed,the permeability and antioxidant activitived of the seedlings of Secale Cereale Lolium were significantly altered(P<0.05).In the freezing-thawing phase(10~-2 ℃),when the temperature dropped to-2℃,the contents of soluble protein,soluble sugar and MDA reached the peak value.As the temperature drops,SOD and POD activity increased gradually.In the thawing-freezing phase(-2~10 ℃),when the temperature rised to10℃,the soluble protein,soluble sugar and MDA content were reduced to the lowest point,SOD and POD activities increased gradually with the decrease of temperature,decreased gradually with the decrease of the rise temperature(P<0.05).2.Simulation acid deposition test: With the increased of acidity,the soluble protein and soluble sugar in the leaves of Secale Cereale Lolium were increased,MDA content decreased,SOD and POD activity with the increase in acidity,was on the rised.There were significant differences among different processing groups.There are significant differences(P<0.05).Under the pH2.5 acid deposition,the soluble protein and soluble sugar content were appeared the lowest value,and the MDA content peaked value.The soluble protein and soluble sugar content peaked value at pH4.5 acid deposition,and the MDA content was appeared the lowest value.SOD and POD activity were appeared the lowest value under pH2.5 acid deposition.The activity of SOD and POD were appeared the peake at pH4.5 acid deposition.3.Combined stress test: The content of soluble protein in leaves of Secale Cereale Lolium was higher than that in single freezing-thawing group under the combined stress.Soluble sugar and MDA content were lower than that of single freezing-thawing group.When the temperature dropped to-2℃,soluble protein,MDA were appeared the peak,when the temperature rosed to 10 ℃,all appeared the minimum value.The change of soluble sugar content was not obvious.SOD and POD activity were higher than that in single freezing-thawing group.When the temperature dropped to-2 ℃,SOD and POD activity were appeared the peake.When the temperature rosed to 4℃,the activity of SOD was the appeared lowest value.When the temperature rosed to 10℃,the activity of POD was appeared the minimum value.The effects of freezing-thawing stress and acid deposition stress in the leaves of Secale Cereale Lolium were more sensitive.There were significant differences in physiological and biochemical indexes between them.Secale Cereale Lolium has a certain cold resistance and acid resistance.Under the adversity stress,the leaves of Secale Cereale Lolium can adaptde to the membrane lipid peroxidation,by activating the antioxidant enzymes in the body and accumulating the osmotic adjustment substances in two ways.