Abstract: [Objective] This study was to investigate the effect of day length, temperature and water on the growth of terminal buds, and to ascertain the cause and mechanism of terminal bud death.[Method] The terminal bud growth and survival of the Paulownia spp. under artificial control by day length, day length and nutrition, day length and temperature and humidity was studied.[Result] Effects of photoperiod was able to seedling height was very significant. Appropriate photoperiod can promote seedlings high growth and extend growth period. The high growth stopping time was in turn 8 h (2011-08-27), 12 h (2011-09-03), 16 h (2011-09-03), 14 h (2011-09-10), 24 h(2011-09-24).24 h photoperiod had the longest growth period and terminal bud germination rateof cutting branches by 24 h treatment was supreme in hydroponic environment.The day length and nutrition had interaction effect on growth of terminal buds.Effect of nutrient on seedling height was very significant in 12 h and 24 h photoperiod. Effects of 12 h photoperiod and fertilization on the high growth was P >PK >K >N; The P or K fertilizer was able to promote seedlings diameter growth in 12 h; Single P or K fertilizer had small terminal bud germination rate of cutting branches in hydroponic environment after 12 h treatment. But terminal bud germination ratio of PK fertilizer was supreme in hydroponic culture of cutting branches. Under 12 h photoperiod with different fertilizer proportion,the seedling height growth mostly stopped on 3 September,2011, which was basically the same as 12 h photoperiod. The height growth with single application of P fertilizer and the treatment 6(N:P:K=2.5:2.5:2.5) stopped on September 10,and the height growth stopping delayed for a week.Under 24 h photoperiod with fertilization, K fertilizer could promote the high growth; CK and K fertilizer had relatively high terminal bud germination rate in hydroponic culture of cutting branches, K fertilizer in 24 h photoperiod played an important role on seedling growth in Paulownia. Under 24 h photoperiod with different fertilizer proportion,the seedling height growth 24 September,2011, which weas basically the same as 24 h.Before the height growth stopped in Autumn, the terminal bud of Paulownia spp. didn't die and continued growing in glasshouse (temperature above 18℃,24 h day length).[Conclusion] Different day length control and day length and nutrient control couldn't assure the terminal buds survival, but the artificial regulation of above 18℃and with a 24 h continuing light could achieve continuous growth of Paulownia spp.

Key words: Paulownia spp., terminal buds, artificial control, continuous growth, stem-join