Abstract: Through cold stress treatment on the following varities: ‘Doulv’, ‘Luoyang Hong’,‘Shouan Hong’ and ‘Yaohuang’ which belong to central plains tree peony cultivars, the relative conductivity, malonaldehyde, soluble sugar and soluble protein of their roots and branches were measured, finally the dynamic change law of physiological index were obtained, and the anatomical structure of roots was observed. The results are as follows: ‘Doulv’ performs the strongest cold resistance, and ‘Luoyang Hong’ shows the weakest. The relative conductivity, malonaldehyde, soluble sugar and soluble protein show significant correlation. Anatomy showed that roots’ tissue included 3 layers: epiderm, cortex and stele. Starch grains in phloem increased obviously in deep dormancy compared with growth period, the quantity of starch grains increased in peony’s roots expressed important relation to cold resistance of central plains tree peony. This research can provide theoretical basis for popularization and application of central plains tree peony cultivars in cold area.

Key words: Central Plains tree peony cultivars, cold resistance, physiology, anatomical structure