Study On Cold Resistance Of Different Almond Cultivars

Almond is a unique economic forest variety in Xinjiang.Under the stress of low temperature,the new shoots of almonds are prone to freeze damage,which leads to the phenomenon of branches being drained and flower buds dying,affecting the growth and development of almonds.Almond is an early flowering plant that is susceptible to chilling damage during flowering,resulting in reduced yield of almonds.Based on the different variety of almond（Wanfeng,Aifeng,Taobadan,Kubadan,Nonpareil and Xiaoruanke）as the experimental material,through the natural wintering almond,under low temperature stress of annual branches,flower bud and flower bud physiological response index as well as the organization structure of research branches,to elucidate the mechanism of cold resistance of almond,and use the Logistic equation,fuzzy membership function and method of comprehensive evaluation of different almond in the size of the cold hardiness under low temperature stress,for almond resources development and utilization and provide theoretical basis and reference to the research on plant cold hardiness.The main findings are as follows:1.Through the study of the changes in the physiological characteristics of almond tree branches during natural wintering,it was found that the almond tree branches were seriously damaged in January;The content of MDA,soluble protein and soluble sugar in the branches increased with the decrease of temperature,the activity of protective enzyme increased,and the water loss rate decreased.There was a significant positive correlation between soluble sugar content and phloem ratio and cold resistance.According to the membership function,the cold resistance of almonds during wintering is comprehensive evaluated:TaoBadan>Kubadan=Nonpareil>Xiaoruanke>Wanfeng>Aifeng.2.By studying the changes of physiological characteristics of almond branches under low temperature stress,it was found that Electrolyte permeability,MDA,LT₅₀,Soluble protein,Water content and Xylem ratio were negatively correlated with cold resistance;POD,Soluble sugar,Starch,Proline,Cortical thickness,Bark rate,Phloem with cold resistance were positively correlated,while SOD,CAT,Shoot radius and Pith were not related to cold resistance.According to the Logistic equation,the semi-lethal temperature of the branches of 6 almond varieties was between-17.1℃^-23.52℃.According to the membership function,the cold resistance was evaluated.The size was:Taobadan>Kubadan>Nonpareil>Xiaoruank>Wanfeng>Aifeng.,the result is consistent with the LT₅₀0 fitting result.3.By studying the changes of physiological characteristics of almond flower buds and flower buds under low temperature stress,it was found that CAT activity,Soluble sugar and Proline were positively correlated with cold resistance,and Conductivity,MDA with cold resistance were negatively correlated.Soluble protein and Starch has nothing to do with the cold resistance of almond flower buds and flower buds.According to Logistic equation,LT50 of 6 almond buds was calculated to be between-20.65℃^-24.83℃,and that of buds was between 3.22℃^-3.25℃.According to the membership function,the evaluation of the cold resistance of the almonds is:Nonpareil>Kubadan>Taobadan>Wanfeng>Xiaoanke>Aifeng,The cold resistance of flower buds is:Kubadan>Nonpareil>Taobadan>Wanfeng>Xiaoanke>Aifeng.4.This experiment studied the cold resistance of different almond varieties,and found that the results of the study on the cold resistance of almond branches under natural overwintering and low temperature stress ranked the same,which was consistent with the results of the TL₅₀0 fitting.The ranking of the cold resistance of almond flower buds and flower buds under low temperature stress is consistent with the results of the TL₅₀0 fitting.It was found that Kubadan、Nonpareil and Taobadan were more cold-resistant varieties.