为了明确绣球〔Hydrangea macrophylla (Thunb.) Ser.〕品种的耐寒性及筛选耐寒性评价主要指标，对40个绣球品种的低温半致死温度（LT₅₀）进行比较和耐寒性分级，在此基础上，对5 ℃、0 ℃、-5 ℃、-10 ℃、-15 ℃、-20 ℃下耐寒品种‘小町’（‘Komachi’）、‘佳澄’（‘Kasumi’）、‘无尽夏’（‘Endless Summer’）和不耐寒品种‘甜蜜幻想’（‘Sweet Fantasy’）、‘灵感’（‘Inspiration’）、‘你我的情感’（‘You and Me Feelings’）叶的抗氧化酶活性及丙二醛（MDA）和渗透调节物质含量进行比较，并对这些耐寒指标进行相关性分析和主成分分析。结果表明：供试绣球品种LT₅₀的波动较大，变化范围为-36.68 ℃～-1.87 ℃，其中，‘小町’的LT₅₀最低，‘佳澄’、‘平瓣’（‘Flat’）、‘蒂亚娜’（‘Tijana’）、‘塞尔玛’（‘Selma’）、‘含羞叶’（‘Elbtal’）、‘花手鞠’（‘Stockings’）、‘蓝色多瑙河’（‘Blue Danube’）和‘无尽夏’的LT₅₀均低于-20 ℃。40个绣球品种的耐寒性被分成不耐寒、较耐寒、耐寒和强耐寒4个等级，分别包含13、18、8和1个品种。6个代表品种的过氧化氢酶（CAT）、多酚氧化酶（PPO）和超氧化物歧化酶活性及MDA、脯氨酸（Pro）、可溶性蛋白质（SP）和可溶性糖含量随温度降低基本呈先升高后降低的变化趋势。相关性分析结果表明PPO活性和Pro含量与LT₅₀呈极显著（P＜0.01）负相关。主成分分析结果表明：前4个主成分的累计贡献率为81.212%，说明这4个主成分基本能够反映绣球品种的耐寒性；PPO活性、CAT活性、Pro含量和SP含量的负荷量绝对值分别在第1、第2、第3和第4主成分中最高。研究结果显示：供试绣球品种间的耐寒性差异较大，‘小町’等9个品种的耐寒性较强，能够在冬季温度偏低地区露天栽培，并可作为绣球耐寒品种选育的亲本。PPO活性、CAT活性、Pro含量和SP含量为绣球耐寒性评价的主要指标，尤其是PPO活性和Pro含量。

 In order to clarify the cold tolerance of Hydrangea macrophylla (Thunb.) Ser. cultivars and screen the main indexes for evaluating cold tolerance, the semi-lethal low temperature (LT₅₀) of 40 cultivars of H. macrophylla were compared, and the cold tolerance was graded, on the basis, the activities of antioxidant enzymes, and contents of malondialdehyde (MDA) and osmotic adjustment substances in leaves of cold-tolerant cultivars ‘Komachi’, ‘Kasumi’, and ‘Endless Summer’ and cold-intolerant cultivars ‘Sweet Fantasy’, ‘Inspiration’, and ‘You and Me Feelings’ under 5 ℃, 0 ℃, -5 ℃, -10 ℃, -15 ℃, and -20 ℃ were compared, and the correlation analysis and principal component analysis of these cold tolerance indexes were conducted. The results show that the fluctuation of LT₅₀ of test cultivars of H. macrophylla is relatively large, with a variation range of -36.68 ℃ to -1.87 ℃, in which, the LT₅₀ of ‘Komachi’ is the lowest, while the LT₅₀ of ‘Kasumi’, ‘Flat’, ‘Tijana’, ‘Selma’, ‘Elbtal’, ‘Stockings’, ‘Blue Danube’, and ‘Endless Summer’ are all below -20 ℃. The cold tolerance of 40 cultivars of H. macrophylla is divided into 4 grades, namely cold intolerant, relatively cold tolerant, cold tolerant, and strongly cold tolerant, containing 13, 18, 8, and 1 cultivars, respectively. The activities of catalase (CAT), polyphenol oxidase (PPO), and superoxide dismutase as well as the contents of MDA, proline (Pro), soluble protein (SP), and soluble sugar of 6 representative cultivars show a tendency to first increase and then decrease in general with the decrease of temperature. The correlation analysis result shows that PPO activity and Pro content show extremely significant (P＜0.01) negative correlations with LT₅₀. The principal component analysis result shows that the cumulative contribution rate of the first four principal components is 81.212%, indicating that the four principal components can basically reflect the cold tolerance of cultivars of H. macrophylla; the absolute values of loads of PPO activity, CAT activity, Pro content, and SP content are the highest in the first, second, third, and fourth principal components, respectively. It is suggested that there are relatively large differences in cold tolerance among test cultivars of H. macrophylla, the cold tolerance of 9 cultivars, such as ‘Komachi’, are relatively strong, and they can be cultivated outdoors in areas with relatively low temperature in winter, and they can be used as parents for breeding cold-tolerant cultivars of H. macrophylla. PPO activity, CAT activity, Pro content, and SP content are main indexes for evaluating cold tolerance of H. macrophylla, especially PPO activity and Pro content.