对自然越冬(2006 年10 月至2007 年3 月)条件下刺柏属(Juniperus Linn.)4 种引进观赏树种叶片的膜电解质外渗率、O₂^-·产生速率、可溶性蛋白质和丙二醛(MDA)含量以及超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)、抗坏血酸过氧化物酶(APX)和谷胱甘肽还原酶(GR)活性进行了测定,并对各指标进行了相关性分析及主成分分析(PCA),在此基础上利用隶属函数法对4 树种的越冬适应性进行了综合评价。结果表明:越冬过程中4 树种叶片9 项生理指标的变化有较大差异,膜电解质外渗率变化幅度均较小,O₂^-·产生速率呈现先升高后降低的变化趋势,可溶性蛋白质含量均逐渐增加,MDA 含量呈现高—低—高的变化趋势,SOD、CAT 和GR 活性的变化无明显规律,POD 和APX 活性则总体上呈增加的趋势。相关性分析结果显示:除GR 活性外,其他8 项生理指标间均存在显著或极显著相关关系。主成分分析结果表明: 9 项生理指标可转化为4 个主成分, 累计贡献率达77. 82%; 4 个主成分可分为生物膜功能因子(可溶性蛋白质和MDA 含量)、膜结构稳定因子(膜电解质外渗率和O₂^-·产生速率)和清除活性氧因子(CAT、APX、GR、SOD 和POD 活性),可作为供试4 树种越冬适应性的鉴定指标。根据综合评价值(D)确定供试4 树种在北京地区的适应性:高山桧‘蓝星’(J. squamata ‘Blue Star’)越冬适应性最强,杂种桧‘黄鹿角’(J. ×media ‘Pfitzeriana Aurea’)和桧‘金羽’(J. chinensis ‘Plumosa Aurea’)次之,欧洲桧‘金锥’(J. communis ‘Gold Cone’)越冬适应性最差。

Under natural overwintering ( from October 2006 to March 2007) condition, membrane electrolyte leakage rate, O₂^-·production rate, contents of soluble protein and MDA, activities of SOD,CAT, POD, APX and GR of leaves of four introduced ornamental species of Juniperus Linn. Were determined, and correlation analysis and principal component analysis (PCA) of above indexes were carried out, and on this basis, comprehensive evaluation on overwintering adaptability of four tree species was performed by subordinate function method. The results show that during the overwintering period, there are greater differences among changes of nine physiological indexes of leaves. Change range of membrane electrolyte leakage rate is smaller; O₂^-· production rate appears a change trend of firstly increasing and then decreasing; soluble protein content gradually increases; MDA content appears a change trend of high-low-high; there is no obvious regularity in change of SOD, CAT and GR activities; and POD and APX activities appear an increasing trend generally. The correlation analysis result shows that except for GR activity, there are significant or extremely significant correlations among other eight physiological indexes. The PCA result shows that nine physiological indexes can be converted to four principal components with an accumulative contribution rate of 77. 82%; four principal components can be divided into membrane function factor (soluble protein and MDA contents), membrane structure stability factor (membrane electrolyte leakage rate and O₂^-· production rate) and scavenging reactive oxygen factor (CAT, APX, GR, SOD and POD activities), which are used as identification indexes for overwintering adaptability of four tree species. According to comprehensive evaluation value (D), the overwintering adaptability of four tree species in Beijing can be defined, that of J. squamata ‘Blue Star’ is the strongest, that of J. ×media ‘Pfitzeriana Aurea’and J. chinensis ‘Plumosa Aurea’is stronger,  that of J. communis ‘Gold Cone’is the weakest.