In vitro plant regeneration from flower buds of populus deltoides and P. maximowiczii

Small immature flower buds of Populus deltoides and P.maximowiczii were cultured on the MS medium containing 0.5㎎/ℓ BA and 0.5-1.0㎎/ℓ NAA for development and growth. Small slices of catkin 5-6㎜ in thickness prepared from the well-developed flower bud 3-4㎝ in length were culture on the MS medium containing 1.0㎎/ℓ BA+0.05㎎/ℓ NAA and 0.5㎎/ℓ BA+0.05㎎/ℓ NAA for adventitious shoot regeneration from P.deltoides and P.maximowiczii, respectively. Average 3.8 shoots from P.deltoedes and 4.1 from P.maximowiczii were regenerated from a slice of catkin. More than 20 shoots can be regenerated from a single mature catkin of poplar such as P.deltoides that is recalcitrant to shoot regeneration. Adventitious shoots were initiated from three different places of an explant, the outer and the cut surface of stalks, and the marginal part of small bracts. The development of immature flower buds in vitro was affected by collecting time. Those collecting in late March were not developed well into mature flower buds. among five different collecting times, July, Sep., Nov., Jan., and Mar.