of 8000 mg·L −1 K-IBA (Sigma Chemical Co., St. Louis, MO) and cuttings of inkberry received 5000 mg·L −1 K-IBA. The basal 1 inch of all cuttings were dipped for 10 s in K-IBA dissolved in water, after which the applied solution was allowed to dry
Bryan J. Peterson, Stephanie E. Burnett, and Olivia Sanchez
Jason J. Griffin and F. Todd Lasseigne
The snowbells (Styrax L.) are a group of flowering shrubs and trees distributed throughout the warm-temperate regions of the northern hemisphere. In all, there are about 120 species, of which only Styrax japonicus Sieb. & Zucc. (Japanese snowbell) and its cultivars are currently of commercial significance. Other species may also posses desirable horticultural traits that could be valuable on their own merit, or used in plant improvement programs. Currently there is little information regarding asexual propagation of the lesser known species. The results herein show that propagation of a diverse collection of Styrax(15 taxa) is possible by stem cuttings. However, species and cultivars within a species do not respond to auxin treatment similarly. The percentage of rooting of many taxa was improved when cuttings were treated with 3000 or 8000 ppm (0.3% or 0.8%) of the potassium salt of indolebutyric acid (K-IBA). However, rooting was unaffected by K-IBA treatment in some taxa, while rooting was negatively affected by K-IBA in others. Additionally, the number of roots produced per rooted cutting were affected by K-IBA treatment. In some instances, K-IBA increased the number of roots per rooted cutting. However, in most of the taxa, root number was unaffected.
Carlos A. Lazcano, Fred T. Davies Jr., Andrés A. Estrada-Luna, Sharon A. Duray, and Victor Olalde-Portugal
Mature cladodes of prickly-pear cactus (Opuntia amyclaea Tenore. `Reina') were treated with five wounding methods and four concentrations of potassium salt indole-3-butyric acid (K-IBA) to stimulate adventitious root formation. The wounding method and K-IBA had highly significant effects on root number and root dry mass of cladodes. Interaction between K-IBA and wounding methods showed that greater root number was obtained at the higher auxin concentrations and with wounding methods that had the greatest cut surface area. K-IBA concentrations from 4,144 to 41,442 μm (1,000 to 10,000 mg·L-1) increased root dry mass. Only the wounding method affected rotting of cladodes. Treatments allowing suberization had a higher percentage of nonrotted cladodes. This research validates the commercial practice of allowing cladodes to suberize early in the propagation cycle. K-IBA altered rooting polarity and stimulated adventitious root formation along the wounded cladode surfaces. The vertical nonsuberized wounding methods and auxin treatments are an excellent classroom demonstration for manipulating rooting polarity. Auxin application and wounding could be of commercial benefit for enhanced rooting in the clonal regeneration of new selections for prickly-pear cactus orchards.
Geoffrey C. Denny and Michael A. Arnold
A study was conducted to determine the effects of substrate, phenological stage of cuttings, and auxin concentrations on the rooting of Texas smoke tree (Cotinus obovatus Raf.). Softwood, semi-hardwood, and hardwood cuttings were treated with either a 0, 5,000, 10,000, or 15,000 mg·L-1 (ppm) potassium salts of indolebutyric acid (K-IBA) and placed in either 50% peat: 50% perlite or 100% perlite rooting substrates. Cuttings were places under an intermittent mist system in a greenhouse for 8 weeks. Softwood cuttings rooted in both substrates, but the 50% peat: 50% perlite substrate produced better-quality rooted only in the 100% perlite substrate. In 100% perlite substrate, the optimal concentration for semi-hardwood cuttings was ≈12000 mg·L-1 (ppm) K-IBA, while hardwood rooting was maximized at 15000 mg·L-1 (ppm) K-IBA or more.
Eugene K. Blythe, Jeff L. Sibley, and John M. Ruter
Stem cuttings of golden euonymus (Euonymus japonicus `Aureo-marginatus'), shore juniper (Juniperus conferta `Blue Pacific'), white indian hawthorn (Rhaphiolepis indica `Alba'), and `Red Cascade' miniature rose (Rosa `Red Cascade') were successfully rooted in plugs of a stabilized organic substrate that had been soaked in aqueous solutions of the potassium salt of indole-3-butyric acid (K-IBA) at 0 to 75 mg·L–1 before inserting the cuttings. Cuttings were rooted under intermittent mist in polyethylene-covered greenhouses with rooting periods appropriate for each species. Rooting percentages showed some increase with increasing auxin concentration with juniper cuttings, but were similar among treatments for the other three species. Number of roots per rooted cutting increased with increasing auxin concentration with cuttings of juniper, Indian hawthorn, and rose, and was greatest using around 60 mg·L-1 K-IBA for cuttings of juniper and Indian hawthorn and 30 to 45 mg·L-1 K-IBA for cuttings of rose.
Jimmy L. Tipton
Effect of cutting age (weeks after budbreak) and K-IBA concentration on percent rooting of Mexican redbud [Cercis canadensis var. mexicana (Rose) M. Hopkins], larchleaf goldenweed [Ericameria laricifolia (Gray) Shinners], littleleaf ash (Fraxinus greggii Gray), and evergreen sumac (Rhus virens Gray) were investigated. For cuttings treated with K-IBA, maximum predicted percent rooting from regression analysis was 88% for cuttings of Mexican redbud taken 4 weeks after budbreak and treated with 21 g·liter-1, 99% for larchleaf goldenweed taken 6 weeks after budbreak and treated with 16 g·liter-1, 86%, for littleleaf ash taken 16 weeks after budbreak and treated with 17 g·liter-1, and 24% for cuttings of evergreen sumac taken 16 weeks after budbreak and treated With 5 g·liter-1. Chemical names used: potassium salt of 1H-indole-3-butanoic acid (K-IBA).
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).
Carlton C. Davidson, Jeff L. Sibley, and D. Joseph Eakes
Traditional propagation courses seldom allow extensive evaluation of the variables required for successful propagation. A series of experiments were designed to give an individual student practical experience in woody plant propagation. Softwood terminal cuttings were taken on five shrub or tree species, dividing each species into separate experiments comparing talc vs. liquid auxin formulations. Selections evaluated included luster leaf holly with treatments of 3000, 8000, and 16,000 ppm K-IBA; hetz holly, crape myrtle, and anise tree with treatments of 1000, 3000, and 8000 ppm K-IBA; and sugar maple with 8000 and 16,000 ppm K-IBA. Budding and seed propagation also were evaluated in sugar maple. In each species, except sugar maple, liquid quick-dip at the highest K-IBA concentration produced the best rooting. The student gained many educational benefits in basic experimental design, evaluation of data collected, and drawing conclusions to findings significant by industry standards. The student also learned and how production cycles have an impact on various methods, development stages of cutting material, and wounding techniques. The practical propagation experience gained was of primary importance thereby further preparing the student for employment in the industry.
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).
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).