Adventitious shoot formation from leaf explants of Rhododendron
A protocol for high frequency adventitious shoot regeneration adventitious shoot regeneration from leaf explants of Rhododendron spp. has been developed. The highest percentage of regeneration and the greatest number of shoots were obtained when leaf explants were cultured on Anderson's medium containing 4.9 μM IBA and 73.8 μM 2iP. Genotypic variation was observed for adventitious shoot regeneration potential among the seven cultivars tested. Regeneration frequencies ranged from 0 to 96%. ‘Lodestar’ had the highest rate of regeneration after 3 months of culture with 96% shoot regeneration and an average of 14 shoots per explant. Regenerated shoots were rooted in soil in about 2 months. This protocol should be useful in applying gene transfer techniques to Rhododendron improvement.
In Vitro Propagation of Rhododendron catawbiense from Flower Buds1

Flower pedicels and ovary bases of 4 cultivars of Rhododendron catawbiense Michx. were cultured in vitro and proliferated granular masses of tissue on Anderson's medium containing indoleacetic acid (IAA) 1.0 or 4.0 mg/liter and 6(γ,γ-dimethylal-lylamino)-purine (2iP) 5.0 or 15.0 mg/liter. These masses formed numerous shoots when cultured on Anderson's medium with lower levels of growth regulators. The shoots were rooted and grown as plants which appeared normal in vegetative characteristics.
In Vitro Propagation of Syringa vulgaris ‘Vesper’

Explants of actively growing shoot tips from greenhouse-grown plants of ‘Vesper’ lilac (Syringa vulgaris L.) initiated new shoots in 2–4 weeks on a modified Murashige and Skoog (MS) revised medium plus 0.1 mg/liter 6-benzylamino purine (BA) and either 0.125, 0.25, or 0.5 mg/liter indoleacetic acid (IAA). These shoots were transferred for multiplication to the same medium but with 7.5 mg/liter BA and 0.1 mg/liter β-naphthaleneacetic acid (NAA). In 5–6 weeks about 6 shoots, 12–15 mm in length, had been produced per explant. There was no increase in the number of shoots by placing them in either a horizontal or inverted position compared to upright. Although excised shoots would root in vitro, rooting was more successful in vermiculite in a plastic-covered flat.