indole-3-butyric acid (IBA) greatly enhanced the rooting of an early-flowering variety of protea, Leucadendron discolor, but had very little effect on a late-flowering variety . IBA transport and metabolism were studied in both varieties after incubating the cuttings in 'H-IBA . More of the radio-label was transported to the leaves of the easy-to-root variety than the difficult-to-root (35-45% and 10%, respectively) . IBA was metabolized rapidly by the cuttings of both varieties and after 24 h most of the label was in the new metabolite . However, free IBA (about 10%) was present in the cuttings during the whole period up to the time of root emergence (4 weeks) . More free IBA was accumulated in the base of easy-to-root cuttings, while in the difficult-to-root variety most of the IBA was found in the leaves . The metabolite was identified tentatively as an ester conjugate with a glucose . It is possible that IBA-glucose serves as a source for free IBA, and the difference between the varieties is a consequence of the free IBA which is released, transported and accumulated in the site of a root formation .

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Additional index words. in vitro propagation, pot plants, RubiaceaeAlberta magna E.H. Mey (Rubiaceae), an attractive flowering evergreen species native to South Africa, is used as a small landscape tree and has potential as a flowering pot plant (Ben-Jaaeov et al., 1989). Propagation, either sexually or by cuttings, is difficult. Seed germination is poor and the seedlings have a long juvenile period. Cuttings taken from mature trees root poorly. We have developed an efficient method for the rapid vegetative propagation of mature-phase plants, in which mature-phase scion wood is grafted onto micropropagated juvenile plants.A terminal stem segment 6 mm long was taken from a 10-mm-tall, l-month-old seedling grown in a growth chamber maintained at 12 hr each 25/17C (day/night). The seedling was subjected to a 12-hr photoperiod of 60 µmol·s -1 ·m -2 provided by cool-white fluorescent lamps. The leaves were removed, the shoot segment was surface sterilized in 1.5% NaOCI for 15 rein, rinsed four times in sterile water, and placed on a filterpaper bridge in a test tube containing 10 ml Anderson's liquid medium (Hartmann and Kester, 1983), pH 4.7, supplemented with 3% sucrose and 1 mg benzyladenine (BA)/ liter. Axillary shoots proliferated rapidly and were subculture on half-strength MS medium solidified with 0.9% agar and containing 3% sucrose with or without BA at 1

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