Abstract:

This article aims to study the differences in cold resistance among different germplasms of Euonymus and comprehensively evaluate their cold resistance, with the hope of screening out germplasm resources with strong cold resistance. Using one-year-old dormant branches from 10 different species and 11 different regions of Euonymus, the electrolyte leakage rate under low temperature stress was determined using the electrical conductivity method. Combined with the Logistic equation, the semi-lethal temperature LT₅₀ was calculated to study the cold resistance of above 21 Euonymus plant materials. The results indicated that under low temperature treatment, the electrolyte leakage rate of the selected Euonymus plants exhibited an S-curve, but there were differences in the rate of increase among different genotypes. The semi-lethal temperature range was between -22.55 and -34.30℃. The order of cold resistance strength among 10 different species was: Euonymus maackii> Euonymus hamiltonianus> Euonymus porphyreus> Euonymus fengchengensis> Euonymus verrucosus> Euonymus macropterus> Euonymus nanus> Euonymus phellomanus> Euonymus schensianus> Euonymus nanus. The order of cold resistance ability in different regions was Montreal, Canada; Taigu of Shanxi, China; McGill, Canada; Ningxia, China; Chengde of Hebei, China; Phuket, Japan; Shenyang of Liaoning, China; Changchun of Jilin, China; Yuci of Shanxi, China; Nanyang of Henan, China; Handan of Hebei, China. Euonymus maackii, Euonymus bungeanus, and Euonymus macropterus are relatively more resistant to cold stress compared to other varieties.

Key words: Euonymus, Euonymus maackii, low temperature stress, cold resistance, electrolyte extravasation rate, lethal temperature for 50% of the population (LT₅₀), germplasm resources