Effect Of Temperature Stress On The Physiological Characteristics Of Almond Growing Superior Plant In Spring

Almond has good economic value,rich variety resources,wide distribution,high yield,reverse spring cold,late frost hazards are frequent,is the main bottleneck restricting the development of almond industry at present,breeding resistant（avoid）late frost improved seed has become an urgent problem in production.In this study,six seedling superior plants of amygdala were taken as test materials,and different individual plants of amygdala were treated with different low temperature（4℃～-4℃）and duration（1h～4h）by low temperature stress method.The physiological characteristics of different gradient of each superior plant were determined,and the cold resistance of amygdala was comprehensively evaluated by principal component analysis and membership function method.The main results are as follows:（1）Under the same treatment time,the conductivity and malondialdehyde content of 11-11,1-4 and 3-34 were significantly higher at-2℃than at-4℃,and the proline content and APX activity of the three superior strains at-2℃were significantly lower than that at-4℃.The soluble sugar content,proline content,SOD activity,PAL activity,APX activity and GSH-Px activity of 11-11 superior strains all reached the maximum value at T19_{（-4℃4h）}.Compared with T3_（4℃4h）,they increased by 49.30%,115.17%,49.42%,139.08%,23.51%and 64.57%,respectively.（2）Under the same low temperature stress,the electrical conductivity,malondialdehyde content,soluble protein content,proline content,SOD activity,PPO activity and APX activity of 11-11,1-4,3-34,14-25,17-44 and 7-35 isolates treated with 3h were all higher than those treated with 4h.At-4℃,the conductivity,soluble protein content,POD activity,PPO activity,APX activity and GSH-Px activity of 11-11 superior strains treated at T18_{（-4℃3h）}were higher than those treated at T19_{（-4℃4h）}.Compared with T19_{（-4℃4h）},they increased by 2.02%,7.95%,226.51%,92.55%,1.45%and 24.35%,respectively.（3）Correlation analysis results show that:Conductivity,malondialdehyde content and APX activity were positively correlated with the cold resistance of amygdala,POD activity and GSH-Px activity were significantly positively correlated with the cold resistance of amygdala,CAT activity and PAL activity were positively correlated with the cold resistance of amygdala.APX activity,GSH-Px activity and cold resistance of almond also reached a very significant positive correlation level.（4）According to the relationship between the physiological cold resistance indexes of the leaves of amygdala,the cold resistance of six amygdala superior plants after low temperature stress was evaluated as 11-11>1-4>3-34>17-44>7-35>14-25 by the membership function method.The comprehensive analysis results showed that the cold resistance of 11-11 superior strains was the strongest,and the cold resistance of 1-4 superior strains and 3-34 superior strains was stronger.Therefore,the cold resistance of 11-11superior strains could be used as the characteristics of superior single strains.