Study On Cold Resistance Of 10 Types Of Central Plains Tree Peony Introduced Into Harbin Area

The central plains tree peony cultivars group's species, types and colors are abundant and it is the richest group in the existing peony groups. Because Harbin belongs to cold region, low temperature is the limiting condition in the introduction of central plains tree peony, but using the proper cold-resistant measure, central plains tree peony can survive after winter, combining with cultivation measures, found that different central plains tree peony cultivars had difference in cold resistance. So variety screening has research value. In order to apply it scientifically in cold regions and use it as an available resource of cold resistant breeding. This paper took 2 and 4 years grafted seedlings as experimental material with low-temperature disposal through by physiological study, compared differences among different central plains tree peony cultivars and carried out the cold resistant research of central plains tree peony. The main results are as follows:1 With artificial and nature low-temperature disposal through by physiological study, anatomical study, recovery test and growth rhythm, found that 10 central plains tree peony cultivars had difference in cold resistance. The 2 years grafted seedlings of 10 central plains tree peony cultivars cold resistant ability sorting is 'Guanshi Moyu'>'Doulv'>'Yaohuang'> 'Shouan Hong' > 'Shengge Jin' > 'Luoyang Hong' > 'Yinhong Qiaodui' > 'Baixue Ta' > 'Hongshi Zi'>'Zilan Kui', which is on basis of quality synthetic evaluation. The 4 years grafted seedlings of 4 central plains tree peony cultivars cold resistant ability ranking is 'Doulv'>'Yaohuang'> 'Shouan Hong' >'Luoyang Hong'.2 With artificial and nature low-temperature disposal through by physiological study, taking relative conductivity, MDA content, soluble sugar content and soluble protein content changes as the evidences, to explain the cold resistant differences among central plains tree peony cultivars from the cold resistant physiological mechanism, and point out the correlation between various physiological targets and the cold resistant ability of central plains tree peony cultivars. Furthermore, the soluble sugar content and the soluble protein content exhibit an extremely positive correlation with the plant's cold resistant ability, the relative conductivity exhibits an extremely negative correlation with the peony's cold resistant ability, the MDA content reflects a remarkable negative correlation with the peony's cold resistant ability. Cultivars which have strong cold resistance are high in soluble sugar content and soluble protein content and low in LT₅₀ and MDA content. The others are opposite.3 Roots' anatomy showed that the anatomical structure of 'Doulv','Luoyang Hong','Shouan Hong' and 'Yaohuang' are similar. Roots' tissue including 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.4 Comparing the climates conditions between Luoyang and Harbin, using the proper cold-resistant measure, 10 central plains tree peony cultivars have already survived after winter. 'Luoyang Hong', 'Yaohuang', 'Guanshi Moyu' and 'Baixue Ta' can blossom, and floral expression are same as in origin. The main reasons that others can not blossom are as follows: plants suffered freeze injury during winter; peony introduced first year may not enter the florescence; improper pruning; the influence of diseases and insect pests; the influence of late spring cold.