Chilling and Heat Requirements of Main Cultivars of Ping‘ou Hybrid Hazelnuts (Corylus heterophylla×Corylus avellana) Analysis of Differential Proteins during Development Stages of Flower Bud and Leaf Bud in Longan Each leaf of buddleia iridoid glycoside Differences in Heat Requirements of Flower and Leaf Buds Make  Hysteranthous Trees Bloom before Leaf Unfolding Changes of Endogenous Polyamines in Leaf and Floral Buds of Pear Trees During Growth and Dormancy