| In this experiment,Liaofu,Altai News,Chuyi and Aleyi,four introduced Hippophae rhamnoides cultivars to Qinghe County,were used as materials,and their phenological periods,New shoots and fruit growth,cold injury in the field,recovery growth and physiological indexes(electrolyte leakage rate,malondialdehyde,soluble sugar,soluble protein,bound water/free water)under low temperature stress were studied by field experiment observation and scientific test in the laboratory.The dynamic changes of index were observed and compared comprehensively.The effects of different physiological and biochemical indexes on the cold resistance of four kinds of Hippophae rhamnoides under low temperature treatment were explored.The excellent varieties in the field were screened,which provided reliable basis for the selection,production,cultivation and popularization of Hippophae rhamnoides cultivars in Xinjiang.The results show that:(1)Observation results of field performance:Through the observation and statistical analysis of four introduced Hippophae rhamnoides cultivars at germination stage,florescence stage,young fruit expansion,fruit discoloration,fruit ripening and deciduous stage,it was found that all the cultivars in Altay region matured in mid-August,showing the characteristics of early ripening;through observation and analysis of the characteristics related to the new slightly and fruit growth,it was found that four cultivars had the characteristics of early ripening.The growth length of new shoots and fruit enlargement period were similar,but there was no significant difference among different Hippophae rhamnoides cultivars.The ratio of vertical and transverse diameter of fruits of Chuyi and Liaofu was close to 2:1,and that of Altai News was close to 1:1,which indicated that the shape of fruits of Chuyi and Liaofu was cylindrical and that of Altai News was spherical.Through temperature and field,the ratio of vertical and transverse diameter of fruits of Altai News was close to 1:1.Observation of cold resistance in the field showed that there were no cold damage characteristics of the tested varieties in the field.(2)The germination rate of Liaofu,Altai News,Chuyi and Aliei did not differ significantly under low temperature treatment,but the physiological indexes of the branches changed to some extent.After different low temperature treatments,the shoot germination rate of four varieties of Hippophae rhamnoides decreased with the decrease of treatment temperature,while those with stronger cold resistance had stronger ability of shoot recovery and growth.The two varieties of Hippophae rhamnoides,Altai News and Chuyi,could germinate at-50℃,but the germination rate was only 13.2 and 9.1,and withered in a short time.The cold resistance of Altai News and Chuyi was stronger.The ratio of free water to bound water of Hippophae rhamnoides branches of Altai News and Chuyi varieties is relatively low,i.e.the water retention ability is strong,showing high cold resistance;the electrical conductivity and malondialdehyde content of Hippophae rhamnoides branches gradually increase,and the electrical conductivity and malondialdehyde content of Altai News and Chuyi are lower than other varieties,reflecting better resistance to stress injury.It was found that the ratio of free water to bound water,conductivity and malondialdehyde content in four kinds of Hippophae rhamnoides branches increased gradually with the decrease of temperature below-20℃.The content of soluble sugar and soluble protein increased first and then decreased slowly with the decrease of temperature,maintaining the osmotic balance in cells.The content of soluble protein and sugar in the branches of Chuyi Hippophae rhamnoides was higher,showing better cold resistance.After comprehensive analysis,the cold resistance of the tested materials is Altay News>Chuyi>Liaofu>Aleyi below-20℃.Altay News has the best cold resistance and is more suitable for planting and popularizing in cold regions of Xinjiang. |
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