Effects Of Different Water Stress On Physiological Characteristics Of Winter Wheat Seedlings

To study the response and adaptation of winter wheat leaves to drought stress and to provide a theoretical basis for guiding the safe production of wheat and disaster reduction and disaster reduction.This experiment was carried out in the greenhouse of Anhui Agriculture University in 2017.The physiological characteristics of wheat seedlings at different seedling stages under three soil water treatments were simulated.The Shannon No.17 wheat was selected to control soil moisture by weighing method,and water was weighed 2 times a day.Taking 7 days as a cycle,the physiological and ecological indexes of wheat leaves were measured,and significant ANOVA and correlation analysis were conducted.Each treatment was controlled for 35 days.The following conclusions are obtained:1.On the seventh day after water control,the activities of antioxidant enzymes in leaves of three water treatments increased rapidly.On the fourteenth day,MDA increased significantly with the increase of SOD and CAT treated by T1 and T2.On the 7-14 day of T3,SOD declined rapidly,POD continued to rise,MDA declined less obviously,and higher than T1 and T2,and even showed an upward trend in Fourteenth days.Correlation analysis showed that the MDA content of T1 and T2 had significant or very significant negative correlation with antioxidant enzymes.The MDA of T3 was in reverse positive correlation with SOD and POD.Although it did not reach a significant level,it showed that with the increase of control water,although SOD and POD increased,it did not protect the membrane lipid oxidation of leaves.2.During the whole water control period,the chlorophyll content of T2 was more active than that of T3.Even on the 21-35 day of water control,the pigment content of T2 was higher than that of T1 and T3 treatments.Compared to T3,the content of pigments changed gently.On the seventh day of water control,the pigment contents of T2 and T3 were all higher than those of T1 treatment,indicating that short-term drought can indeed increase chlorophyll content.Correlation analysis showed that chlorophyll content was positively correlated with antioxidant enzyme activities,especially significant positive correlation with SOD and CAT.3.The water content of T2 leaves varied slowly and steadily,especially after twenty-first days,which was similar to that of T1 treatment.The variation of free water and bound water content in the T3 treatment leaves fluctuates greatly,especially on the 21-35 day,the free water increases sharply and the bound water decreases rapidly.It shows that the T3 and the T2 and T1 are significantly affected by the long time stress.The physiological correlation analysis showed that there was significant or extremely significant negative correlation between the water content of leaves,bound water content and various antioxidant enzymes,and the content of the bound water of leaves was negatively correlated with the content of chlorophyll,while the ratio of free water / bound water was positively correlated with the activity of antioxidant enzymes,especially with CAT and POD.There is a positive correlation.The ratio of free water / bound water treated by T1 and T2 has a significant positive correlation with CAT,and the ratio of T2 treatment has a significant negative correlation with the MDA content,showing obvious resistance.4.The difference of temperature difference between leaf root to leaf and leaf temperature shows that the difference of temperature between leaf root and leaf gradually decreases with the decrease of soil moisture,and the difference of temperature difference between leaf root to leaf slightly leaf and temperature difference decreases with the prolongation of stress time.On the seventh,twenty-first,twenty-eighth day of controlling water,the difference between leaves and temperature was higher than that of leaves,but on the fourteenth,thirty-fifth day it appeared as leaf > leaf root.In 11:00-15:00,the overall average performance is T3>T2>T1,but in some periods T1 value is higher than T2 and T3 treatment.On the 7-14 day of water control,leaf temperature difference increased rapidly and did not decrease with the increase of saturated vapor pressure difference.At the late 21-35 days,leaf temperature difference gradually decreased,and decreased with the increase of saturated vapor pressure difference.