PLANT-REGENERATION FROM AGED-CALLUS OF THE WOODY ORNAMENTAL SPECIES LONICERA-JAPONICA CV HALLS PROLIFIC

Callus cultures were initiated from in vitro grown leaf, stem and root segments of Lonicera japonica ''Hall's Prolific'', on a medium contai ning 10.7 muM alpha-naphthtylacetic acid and 2.7 muM benzyladenine, wh ile media with 2,4-dichlorophenoxyacetic acid led to a rapid necrosis of explants. Shoot regeneration from true-callus (i.e. without any par t of the original explant) was achieved for the three different source tissues within 12 weeks. The highest rate of regeneration was obtaine d by using benzyladenine (4.4 to 44.4 muM) as the sole hormone in the medium. The regenerated shoots were readily elongated and rooted on th e same medium as used for multiplication, and plantlets were subsequen tly transferred to greenhouse conditions, where nearly 100% of them we re successfully acclimatized. This is the first example of plant regen eration from aged (greater-than-or-equal-to 6 month-old) true-callus o f a woody ornamental species.