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James R. Ault

Shoot initiation and multiplication were obtained in vitro from immature flower bud and leaf explants of Veltheimia bracteata Bak. `Lemon Flame' and from leaf explants of V. bracteata `Rosalba' cultured on a Murashige and Skoog (MS) medium supplemented with sucrose at 30 g•L–1, and either 8.87 μm BA plus 0.54 μm NAA or 8.87 μm BA plus 5.40 μm NAA. Shoot initiation and multiplication was obtained from a single leaf explant of Veltheimia capensis (L.) DC. on MS medium with 8.87 μm BA plus 0.54 μm NAA. Shoots of the three genotypes rooted on subculture to medium with 0.0, 4.14, or 8.29 μm K-IBA or 0.0, 4.46, or 8.92 μm K-NAA. Maximal rooting was 98% for V. bracteata `Lemon Flame', 95% for V. bracteata `Rosalba', and 98% for V. capensis, from medium with 4.46 μm KNAA. Rooted shoots were acclimatized for 3 to 4 weeks. Overall survival percentage was 69% for V. bracteata `Lemon Flame', 65% for V. bracteata `Rosalba', and 83% for V. capensis. Chemical names used: 6-benzyladenine (BA); potassium salt of indole-3-butyric acid (K-IBA); potassium salt of 1-naphthaleneacetic acid (K-NAA); 1-naphthaleneacetic acid (NAA).

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James R. Ault

Optimal axillary shoot proliferation was obtained from stem explants of a clone of Eriostemon myoporoides DC. on Murashige and Skoog (MS) basal medium containing 0.1 mg BA/liter, and of Eriostemon `Stardust' on MS medium containing 0.5 mg BA/liter. Overall average number of shoots and shoot lengths for all treatments was greater for E. `Stardust' (22.4 shoots and 12.1-mm shoot length) than for E. myoporoides (4.5 shoots and 8.3-mm shoot length). Maximum percent rooting of E. myoporoides (42%) and E. `Stardust' (95%) was obtained on MS medium supplemented with 1.0 mg K-IBA/liter for E. myoporoides and 0.1 mg NAA/liter for E. `Stardust'. Overall average percent rooting and root lengths were greater for E. `Stardust' (42% rooting and 11.0-mm root length) than for E. myoporoides (27% rooting and 2.3-mm root length). For E. `Stardust', reducing sucrose in the rooting medium from 50 to 25 g·liter-1 significantly decreased overall average percent rooting to 1670 and root length to 6.8 mm. Plantlets of both clones were acclimatized in the greenhouse and transferred successfully to soil, although survival was <7070. Chemical names used: N -(phenylmethyl) -l H -purine-6-amine (BA); potassium-l H -indole-3-butyric acid (K-IBA); l-naphthaleneacetic acid (NAA).

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James R. Ault

Shoot formation was obtained from Lachenalia arbuthnotiae W.F. Barker, L. bulbifera (Cyrillo) Engl., and L. purpureo-coerulea Jacq. leaf tissue explants cultured on Murashige and Skoog (MS) medium supplemented with sucrose at 30 g·liter–1, 8.87 μm BA, and 0.44 μm K-NAA. Shoots of all three species rooted on subculture to MS medium supplemented with 0.0, 4.14, or 8.29 μm K-IBA or 0.0, 4.46, or 8.92 μm K-NAA. Maximum percent rooting was ≈81% from treatment with 4.14 μm K-IBA for L. arbuthnotiae and with 8.29 μm K-IBA for L. purpureo-coerulea; it was 59% from treatment with 8.92 μm K-NAA for L. bulbifera. Rooted and nonrooted shoots were acclimatized in a greenhouse. Survival of rooted plants was 93% for L. arbuthnotiae, 95% for L. bulbifera, and 94% for L. purpureo-coerulea. Survival of nonrooted shoots was 71% for L. arbuthnotiae and 91% for L. bulbifera. Chemical names used: 6-benzyladenine (BA); potassium salt of indole-3-butyric acid (K-IBA); potassium salt of 1-naphthaleneacetic acid (K-NAA).

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James R. Ault

Shoot formed in vitro from twin-scale explants of Eucomis autumnalis (Mill.) Chitt., E. comosa (Houtt.) Wehrh., and E. zambesiaca Bak. cultured on Murashige and Skoog (MS) basal medium containing 0.0, 4.4, 11.1, or 22.2 μm BA and 0.0 or 5.4 μm NAA. In all three species, shoot proliferation was obtained from single-shoot explants subcultured on medium supplemented with 4.4, 11.1, or 22.2 μm BA and 0.0 or 5.4 μm NAA. Shoots of all three species rooted readily on MS medium supplemented with 0.0, 2.7, 5.4, or 10.8 mm NAA. Overall rooting percentages were 95%, 98%, and 100% for E. autumnalis, E. comosa, and E. zambesiaca, respectively. Plant survival for rooted shoots of all three species was 100% following transfer to a 1 perlite: 1 peat (v/v) medium in the greenhouse. Chemical names used: 6-benzyladenine (BA); 1-naphthaleneacetic acid (NAA).

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James R. Ault

Shoot tip and stem segment explants collected from greenhouse-maintained plants of Hymenoxys acaulis var. glabra were cultured in vitro for shoot initiation on a Murashige and Skoog (MS) medium supplemented with 30 g·L-1 sucrose, 2.5 μm BA, and 7 g·L-1 agar at a pH of 5.7. Unbranched shoot explants were subcultured to MS medium with 0.0, 0.5, 1, 2, 4 or 8 μm BA for shoot proliferation. A maximum of 10.3 shoots per explant was produced on the medium with 2.0 μm BA. Nonrooted shoots were subcultured to MS medium with 0.0, 0.5, 2, or 8 μm K-IBA for rooting. Maximum rooting was 90% on MS medium with 0.5 μm K-IBA. Rooted shoots were greenhouse-acclimatized for 10 days. Overall survival was 75%. Chemical names used: 6-benzyl adenine (BA); potassium salt of indole-3-butyric acid (K-IBA).

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James R. Ault

Shoot proliferation cultures were established in vitro using flower-stem explants from two different interspecific hybrid plants of Liatris. Explants taken on two dates from field-grown plants were successfully established and axillary shoot growth promoted on a medium consisting of Murashige and Skoog basal salts and vitamins with 30 g·L-1 sucrose, 1.0 μm BA, and 7.0 g·L-1 agar, with a medium pH = 5.7. Initial explant contamination rates were significantly higher among explants collected later in the growing season. Addition of BA (1.0, 2.0, 4.0, 8.0, or 16.0 μm) improved shoot formation compared to the control for both plants. Proliferation rates differed between the dates of establishment, the plants, and the BA treatments. Shoots rooted readily in medium without PGRs or with 1.0, 2.0, 4.0, or 8.0 μm K-IBA. Overall rooting was 88%. About 90% of the plants rooted in the presence of 1.0 μm K-IBA were successfully established in the greenhouse. Chemical names used: 6-benzyl adenine (BA); potassium salt of indole-3-butyric acid (K-IBA).

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James R. Ault and Kayri Havens

Shoot explants from actively growing, greenhouse-maintained plants of Baptisia `Purple Smoke' were cultured in vitro for shoot initiation on Murashige and Skoog (MS) basal medium containing vitamins and supplemented with 30 g·L–1 sucrose, 8.87 μm BA, and 4.14 μm K-IBA. All subsequent media were supplemented with 2.47 mm NaH2PO4 to enhance shoot growth. Single-node explants were subcultured for shoot multiplication on MS medium with either no plant growth regulator or with 2.22, 4.44, 8.87, 17.74, or 35.48 mm BA in combination with 0.0 or 4.14 μm K-IBA. Explants produced a maximum of 4.1 shoots on the medium with 2.22 μm BA. Shoots rooted on all concentrations of K-IBA (2.07, 4.14, 10.36, or 20.72 μm) and K-NAA (2.23, 4.46, 11.15, or 22.29 μm) tested. Maximum rooting was 100% on MS medium with 11.15 μm K-NAA; however, this treatment induced copious stem callusing. Rooted shoots were greenhouse-acclimatized for 2.5 weeks. Overall survival was 86%. For optimal rooting and subsequent acclimatization, treatment with 2.23 μm K-NAA is recommended; this resulted in 83% rooting and 87% acclimatization. Chemical names used: N 6 benzyladenine (BA); potassium salt of indole-3-butyric acid (K-IBA); potassium salt of 1-naphthalene acetic acid (K-NAA).