Response Of Different Varieties Of Blueberry To NaCl And High Temperature Stress After Transplanting

To provide a theoretical reference for the screening and development of salt-tolerant and high-temperature-tolerant blueberry varieties,this study compared the resistance of different blueberry in vitro seedlings to high temperature and Na Cl stress.Main research contents and results are as follows:1.Using the Vaccinium uliginosum ‘Spartan’—a kind of blueberry in vitro seedling as the material and adopting the orthogonal test design,the effects on proliferation of blueberry seedlings of different supports（agar,perlite,vermiculite）,nutrient solution（WPM,1/2WPM,1/4WPM）and ZT concentrations（0.5mg/L,1mg/L,1.2mg/L）were studied.The result shows :The order of the three factors affecting the proliferation of blueberry test tube seedlings was:support>nutrient solution>ZT concentration.The most suitable static nutrient solution for blueberry cluster bud proliferation was selected as perlite + WPM + 1 mg/L ZT.This result provided a technical basis for the engineering of blueberry Vaccinium uliginosum ‘Spartan’seedlings.2.Under Na Cl stress,the northern highbush blueberry ‘Spartan’ 、 ‘Duke’ 、 the southern highbush blueberry ‘sunshine blue’ and the V.angustifolium ‘Beikong’ of tube seedlings after transplanting seedlings were used as test materials.Different concentrations of Na Cl solutions（0,50mmol/L,100mmol/L,150mmol/L,175mmol/L）were used to simulate the salt stress environment during the cultivation process,and to determine the seedling growth indexes（basal branch thickness,trunk and shoot length,leaf color index）and physiological indexes（Pigment content,malondialdehyde content,soluble protein content,SOD activity,POD activity）.Comprehensive evaluation of its salt tolerance according to membership function analysis.The results showed that under 50mmol/L Na Cl treatment,the variation of basal branch thickness of each variety was greater than that of control group.The pigment content,SOD and POD activity showed an upward trend compared with the control group;as the salt concentration continued to increase,compared with the control group,the changes in the thickness of the basal branches and the length of the new shoots of the trunk showed a general downward trend.The content of pigment,soluble protein and malondialdehyde in the leaves of blueberries was significantly higher than that of the control under Na Cl stress,and the enzyme activities decreased in turn.When the Na Cl concentration was greater than 150 mmol/L,the growth and physiological indicators of various blueberry seedlings of various varieties changed significantly,and the seedlings was obviously damaged by salt.The Na Cl concentration of 150 mmol/L can be used as a reference value for the salt tolerance study of blueberry seedlings.The analysis results of the membership function method showed that the blueberry ‘Spartan’ and ‘Duke’ belonged to the group of salt tolerance,blueberry ‘Beikong’ belonged to the group of salt sensitive varieties,and the moderately tolerant group is blueberry ‘sunshine blue’.3.Under heat stress,four different varieties（the northern highbush blueberry ‘Spartan’and ‘Bluecrop’,the southern highbush blueberry ‘sunshine blue’,the V.angustifolium‘Beikong’）of blueberries were used as test materials.Setting different temperature pretreatments（25℃ pretreatment and 30℃ pretreatment）,artificially simulate 40 ℃ high temperature stress.Through comprehensive analysis of four varieties of blueberry seeding leaves’ physiological indexes,such as pigment content,malondialdehyde content,soluble protein content,SOD and POD activity under high temperature stress,preliminary comparison of heat tolerance of four varieties : under heat stress pretreatment at 25℃,according to the average membership,the growth adaptability of four blueberry varieties’ under high temperature environment was ranked as follows: ‘sunshine blue’,‘Bluecrop’,‘Spartan’,‘Beikong’.Under high temperature pretreatment at 30℃,the growth adaptability of four blueberry varieties under high temperature environment can be ranked as follows:‘Bluecrop’,‘Spartan’,‘sunshine blue’,‘Beikong’.Different pretreatment temperatures had different effects on the high temperature treatment of various blueberries.When the pretreatment temperature of V.angustifolium blueberry in the northern air was 25℃ and 30℃,the difference in the treatment of 40℃ high temperature stress was not significant.The high temperature stress under 30 ℃ pretreatment with Spartan and Bluecrop were better than that under 25 ℃ pretreatment.The heat stress with sunshine blue at 25℃ was better than that at30℃.