Study Of Cold-resistance Cultivars (clone) In Crabapple (Malus Spp)

Ornamental crabapple is one of the most high Ornamental value and cold-effective tree inthe wold, widely used in the wold landscape. To study on the main physiological indicatorswhich effected the cold-resistance of ornamental crabapple （Malus spp.） and to selectcold-resistance ornamental crabapple cultivars （clones）. The one-year-old dormant branchesof fifteen ornamental crabapple cultivars （clones） were used as the materials. By thelow-temperature of^-10℃、^-15℃、-20℃、-25℃and-30℃stress treatment, the REC, thecontent of soluble sucrose, soluble protein, proline, MDA and activity of SOD and POD ofthe treated branches were determined. The results showed that1. As the temperature was decreasing, the REC rising. The LT₅₀of15ornamental crabapplecultivars （clones） was obtained with fitting Logistic equation.The fifteen crabapple cultivars（clones） LT₅₀is#3（-31.9℃）, T₂（-31.20℃）,T₃（-30.70℃）,T₁（-30.70℃）,#7（-28.90℃）,M.‘Snowdrift’（-27.70℃）、M.‘Kelsey’（-27.03℃）, M.‘Red Splendor’（-26.90℃）, M.‘Strawberry Parfait’（-25.58℃）, M.‘Jew elberry’（-25.30℃）, M.‘Royalty’（-25.30℃）,M.‘Sparkler（’-25.12℃）,M.‘Radiant（’-24.70℃）, M.‘Pink Spire（’-23.80℃）, M.‘Adams’（-23.39℃）.2. With the temperature was decreasing, the activity of SOD demonstrated an up-to-downpattern. The POD activities of different cultivars （clones） were quite different, showing andown to up pattern. Soluble protein and MDA had a similar trend, showing an up-to-downpattern, respectively. The content of soluble sucrose gradually accumulated. With thetemperature decreasing, proline showed an up-down-up pattern.3. Principal component analysis showed that the physiological indicators, which had agreater impact on the cold-resistance of ornamental crabapple were SOD, REC, solubleprotein and soluble sucrose.4. According to membership function method, the membership function values were gotten.The results showed that the freezing tolerance of tested ornamental crabapple was:‘Kelsey’＞T₂＞#3＞T₃＞‘Sparkler’＞#7＞T₁＞‘Radiant’＞‘Red Splendor’＞‘Royalty’＞‘Strawberry Parfait’＞‘Snowdrift’＞‘Pink Spire’＞‘Jew elberry’＞‘Adams’. Theornamental crabapple clones T₁, T₂, and T₃native in Shandong Provence had a betterresistance to cold. 5. The leaves of M.‘Radiant’ protein SDS-PAGE analysis state that from4℃to0℃lowtemperature conditions, the difference of time stress is not caused by difference in proteinexpression. Under^-10℃low temperature stress, a difference protein band appears near30KD,at the temperature of-25℃, the band still exists.