Principal Component Analysis And Cold Tolerance Evaluation Of Membrane Lipid Component In Different Varieties Of Autumn Chrysanthemum Cultivers Under Low Temperature

Take autumn Chrysanthemum early-flowering varieties ‘Zaofenpan’、‘Jin fengling’、‘Tongquechunshen’、‘Richudongfang’、‘Tanxiangshizi’and autumnChrysanthemum late-flowering varieties ‘Mobao’、‘Guandongxinxia’、‘Xingguangcanlan’、‘Yunlongfengwu’ as test materials,this experiment determined thecomposition and content of myristic acid(C14:0)、 hexadecanoic acid(C16:0)、octadecanoic acid(C18:0)、 docosanoic acid(C22:0)、 oleic acid(C18:1)、 linoleicacid(C18:2)、linolenic acid(C18:3)of the Chrysanthemum leaves and roots under to16℃、5℃of nine culture and-4℃、-8℃of ‘Taipingdexiaogu’、‘Jinfengling’、‘Mobao’ and ‘Xingguangcanlan’, respectively.Measured the REC of theChrysanthemum leaves under low temperature,and the principal component analysiswas applied to comprehensive evaluate the cold tolerance abilities. Research showsthat:(1)The membrane fatty acid in leaves and roots of4autumn chrysanthemumcultivars were mainly composed of palmitic acid,linoleic acidand linolenic acid,themain component of unsaturated fatty acid in leaves was linolenic acid,but linoleic acidin roots,the content of which was more than49.81%and35.49%in total fattyacids,respectively. The palmitic acid was main kind of saturated fatty acid. Lowtemperature contributed to the formation of unsaturated fatty acids and the incrementof IUFA（Index unsaturated fatty acid）,the IUFA of late-flowering cultivars were moresignificantly affected by subzero low temperature, unsaturated fatty acid contents inleaves were higher evidently than those in roots in whole experiments,there existssome differences in membrane lipids response to low temperature in leaf and root.(2)After cold treatment,as the temperature depressed,the REC for the leaves wasraising.The changing range about REC of leaves showed slowly-fast-slowly trendwith temperature reducing,that Was“S”increasing curve.The correlation coefficientswere form0.957to0.998.according to the REC of different low temperaturestress,together with Logistic equation to determine the LT50of nine autumnchrysanthemum cultivars, the results show that: the LT50of ‘Zaofenpan’、‘Jin fengling’、‘Tongquechunshen’、‘Richudongfang’、‘Tanxiangshizi’、‘Mobao’、‘Guandongxinxia’、‘Xingguang canlan’ and ‘Yunlongfengwu’ was-7.115℃、-8.730℃、-9.381℃、-6.916℃、-8.449℃、-9.931℃、-8.289℃、-9.700℃and-7.385℃respectively.(3)It proved that the relationship between C18:1、C18:2、C18:3、 USFA/SFA、IUFA、C18:3/(C18:1+C18:2)、C18:3/(C18:1+C18:2+C18:3)、C18:2/(C18:1+C18:2+C18:3) and LT50werecloser with the temperature decreasing.,the LT50is positively related with USFA/SFA andC18:2/(C18:1+C18:2+C18:3),but negatively correlated with C18:1、C18:2、C18:3、IUFA、C18:3/(C18:1+C18:2)and C18:3/(C18:1+C18:2+C18:3).(4)Principal component analysis showed that the physiological indicators,which had agreater impact on the cold resistace of autumn Chrysanthemum were C18:3、C18:2/(C18:1+C18:2+C18:3)、C18:3/(C18:1+C18:2)、C18:3/(C18:1+C18:2+C18:3)、IUFA. theseindicators are closed to the cold tolerance abilities,and played important role inimproving cold resistance,therefore,they can be the important physiological index ofcold resistance. Though the linkage chuster analysis, the autumn Chrysanthemumcould be divivied into three groups based on the cold resistance comprehensive index.‘Mobao’、‘Xingguangcanlan’and ‘Tanxiangshizi’ exhibit the strongest cold resistance,‘Jinfengling’、‘Zaofenpan’ stronger,‘Tongquechunshen’、‘Yunlongfengwu’、‘Richudongfang’、‘Guandongxinxia’ a little weaker.It showed that the result ofcomprehensive evaluation applied to the principal component analysis and the resultof REC accord to the Logistic equation to different autumn Chrysanthemum varietiesare consistent except ‘Jinfengling’、‘Tanxiangshizi’.According to the Logisticequation to obtain LT50can serve as a rapid determination of autumn Chrysanthemumsimple method of cold resistance.