Bourgeon and Main Stem Extension of Terminal Buds of Paulownia elongata Seedlings Effects of several regulation measures on change of endogenous hormones in terminal bud at flowering stage and the flower-formation and fruit-setting of Longan GENETIC VARIATION AND FAMILY SELECTION ON COLD HARDINESS OF CHINESE FIR SEEDLINGS Progress in the Death Mechanism Research of Paulownia spp. Terminal Buds Dynamic Changes of Endogenous Hormones in Terminal Buds from Different Crown Position of One-Year-Old Paulownia