关键词: 苹果, 砧木, 实生后代, 电阻抗图谱, 抗寒性, 电阻, 弛豫时间

Abstract: The 18 two-year-old seedlings of the apple rootstocks（Malus micromalus Makino）were used to analyse the relation between non-frost-exposed electrical impedance spectroscopy（EIS）parameters and frost hardiness（LT50 measured by the electrolyte leakage）in shoots of apple rootstocks. Results showed that the high-frequency resistances（r）and low-frequency resistances（r1），extracellular resistance（re），as well as relaxation time（τ）significantly correlated with the frost hardiness（r from﹣0.737** to﹣0.877**）in three different periods（March，July and November），and intracellular resistance（r i）had significant correlation with the frost hardiness（r =﹣0.857**）in November. The results suggested that these EIS parameters could be used to evaluate the frost hardiness of apple seedling rootstocks shoots without exposure to artificial freezing and according to path coefficient of every parameter in the three periods，re was the best parameter. 　

Key words: apple, rootstock, seedling plant, electrical impedance spectroscopy（EIS）, frost hardiness, resistance, relaxation time