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  • Author or Editor: Brian Maynard x
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Abstract

The discovery and use of auxins in rooting and the development of mist propagation are unequivocal milestones in the history of propagation due to their broad applicability and effectiveness. Stock plant etiolation may prove to be in a similar class with these techniques. The practical use of stock plant etiolation to improve rooting in cuttings has largely been spurred on in the past 10 years by the successes achieved by Howard and others at the East Mailing Research Station, United Kingdom (9). For all the renewed interest, however, the practice of withholding light to improve propagation is probably an ancient one, having been employed every time a stool bed or layer was made or even a cutting inserted into opaque media.

Open Access

Constructed wetlands are an effective, low-cost method of water treatment that may reduce agricultural pollutants from nursery runoff. It has been suggested that the expense of implementing such systems could be recovered by growing aquatic plants that could be sold to retail and wholesale markets. However, this demand could probably be satisfied through a few wetlands. It would be desirable if more traditional nursery crops could be incorporated into treatment wetlands. Several taxa of Cannas, Iris, and ornamental grasses are selected cultivars of wetland plants that have been used in treatment wetlands for decades. However little data exists on these cultivar's nutrient uptake rates and survivability in treatment wetlands. Nutrient uptake and growth rates of Canna × generalis cultivars `Aflame', `King Humbert', and `Pretoria', Glyceria maxima `Variegata', Iris pseudacorus, Iris versicolor, Phalaris arundinacea `Luteo-Picta', Pragmites australis `Variegata', and Spartina pectinata `Aureo-marginata' were compared to the widely used Typha latifolia. Single divisions of each were established in a constructed wetland and batch fed weekly a commercial fertilizer solution reconstituted to 100 ppm-N. Plants were harvested after 75 days and biomass and tissue nutrient content was determined. Mean biomass of Typha latifolia was 212 g/division and nitrogen and phosphorus accumulation was 4.5 and 0.8 g/division, respectively. The biomass of the other species ranged from 101 to 175 g/division and had total accumulation of nutrients ranging from 2.5 to 3.8 g nitrogen/division and 0.35 to 0.85 g phosphorus/division.

Free access

Cupric hydroxide formulated as Spin Out™ [7% Cu(OH)2 in a latex carrier] was used to prevent the rooting-out of Taxus × media Rehd. `Densiformis' root balls into surrounding mulch or soil during storage over a 4-month period. Treatments evaluated in one study included: painting the bottom of the root ball with copper-paint, setting the root ball on copper-treated burlap or ordinary copper-treated burlap; rewrapping the root ball with copper-treated burlap before mulching or burlapping with copper-treated burlap, with appropriate controls. All treatments provided good control of rooting-out after 12 to 16 weeks storage. The most effective treatments were setting the root ball on copper-treated burlap (unmulched; 92% reduction in root count after 16 weeks) and rewrapping or burlapping into copper-treated burlap (mulched; 90% and 86% reduction in root count after 16 weeks). A second study used TexR® Agroliner (Spin Out™-treated non-woven fabric), on which root balls were set (unmulched treatments), rewrapped or burlapped (mulched treatments). TexR® Agroliner stopped rooting-out completely without adversely affecting plant quality. Using copper-treated burlap to prevent rooting-out during storage can reduce the incidence of re-balling and root removal prior to shipping and planting B&B nursery stock.

Free access

Effects of stockplant etiolation, stem banding, exogenous auxin, and catechol on the rooting response of softwood cuttings of paperbark maple (Acer griseum Pax.) were studied. Etiolated cuttings rooted better than light-grown cuttings, while stem banding did not affect rooting percentage (light-grown, 10%; light-grown + banding, 18%; etiolated, 41%; etiolated + banding, 37%). IBA did not promote, but catechol inhibited rooting (control, 31%; IBA, 37%; catechol, 17%; IBA + catechol, 21%). Root number was increased by IBA and unaffected by catechol. The distance from the cutting base to the first emerged root was measured as an indication of auxin toxicity. IBA interacted with etiolation and stem banding to increase this distance, which was greater in catechol-treated cuttings. Chemical names used: 1,2-benzenedio1 (catechol); 1H-indole-3-butanoic acid (IBA).

Free access

New shoot growth of Carpinus betulus `fastigiata' was treated with stockplant etiolation and stem banding treatments and sampled for anatomical study at intervals over a 16-week period of greening following etiolation. Shading effects on the anatomy of the stem were also investigated. Numerous anatomical changes were noted with stem age and stockplant treatment. Among these were etiolation effects on the lignification of the secondary xylem, thickness of the periderm, and an increase in the percentage of sclereid-free gaps in the perivascular sclerenchyma, Stem banding increased the widths of the cortex and pith. Concomitant propagation studies revealed significant etiolation, shading, and banding effects on rooting percentages and root numbers. Using multiple linear regression methods rooting capacity was modelled best by linear combinations of the widths of the pith, non-lignified secondary xylem, cortical parenchyma and periderm, as well as the percentage of gaps in the sclerenchymatic sheath remaining non-sclerified. It is proposed that the development of sclereids in potential rooting sites reduces rooting potential. The exclusion of light during initial shoot development retards sclereid development by up to 3 months following treatment, which correlates well with observed increases in the rooting potential of etiolated and/or banded stems.

Free access

Three experiments were undertaken to examine the effect of stockplant etiolation, shading, and stem banding, prior to cutting propagation, on the auxin dose-response of rooting in stem cuttings of Carpinus betulus `fastigiata'. A 2 × 2 factorial of etiolation and banding utilized stockplants forced in a greenhouse, etiolated for 1 week and banded with Velcro™ for 1 month. In a separate study shading was applied up the time of harvesting cuttings. IBA was applied to cuttings as an aqueous ethanol quick dip in concentrations ranging from 0 to 80 mM. Rooting percentage and number were best described, up to a peak response, by a linear function proportional to the logarithm of applied IBA. The inhibition of rooting by supra-optimal IBA was directly proportional to IBA concentration. Cuttings prepared from shoots which had been etiolated or banded rooted better at low IBA and at their respective optimal IBA levels. Cuttings from shoots receiving both etiolation and banding yielded higher rooting percentages and more roots per rooted cutting on average. Etiolation and banding served to increase both initial and maximum rooting capacities, and to reduce the sensitivity of cuttings to supraoptimal auxin-induced inhibition of adventitious root initiation. The auxin dose-response interacted with shading to yield the best rooting at 95% shade and 3.7 mM IBA.

Free access

New shoot growth of Carpinus betulus L. fastigiata was subjected to stock plant etiolation and stem banding (a 2.5-cm square of Velcro applied to the shoot base) treatments and sampled for histological study at intervals over a 16-week period of shoot development following etiolation. Effects of partial shading on histology of the stem were also investigated. Numerous histological changes were noted with stem development and stock plant treatment. Among these were a reduction in lignification of the secondary xylem and thickness of the periderm, and an increase in the percentage of sclereid-free gaps in the perivascular sclerenchyma with etiolation. Concomitant propagation studies revealed significant etiolation, shading, and banding effects on rooting percentages and root numbers. Rooting capacity was modelled using linear combinations of the widths of nonlignified secondary xylem, cortical parenchyma and periderm, as well as the percentage of gaps in the sclerenchymatic sheath remaining free of sclereids. It is proposed that the development of sclereids in potential rooting sites reduces rooting potential. The exclusion of light during initial shoot development retards sclereid development by up to 3 months following treatment, which correlates well with observed increases in the rooting potential of etiolated stems.

Free access

In a study of stock plant etiolation and stem banding, stem cuttings of upright European hornbeam (Carpinus betulus L. `Fastigiata') were taken at 2-week intervals over 4 months following budbreak and rooted under intermittent mist for 30 days. Percent rooting and root counts declined with increasing cutting age. Stock plant etiolation and stem banding increased percent rooting and root counts throughout the study, with the combination of both treatments yielding the best rooting. In nontreated stems, > 75% rooting was achieved only within 4 weeks of budbreak. Etiolation and stem banding resulted in rooting ≥ 75% up to 3 months after budbreak. In two shading studies, stock plants were grown in a glass greenhouse under 0%, 50%, 75%, or 95% shade, or initially etiolated (100% shade) for 1.5 days. Cuttings were taken after 2.5 and 60 days and treated with IBA concentrations ranging from 0 to 4.9 mm before rooting under intermittent mist for 30 days. Percent rooting increased proportionally to the degree of shading, with a maximum response at 95% shade. Cuttings taken at 60 days were less responsive to etiolation and shading than those harvested at 25 days. Auxin concentration interacted with shading to yield, at 95% shade and 3.7 mm IBA, the highest rooting percentage and the greatest root counts and lengths. Light exclusion by etiolation, stem banding, or shading can extend the cutting propagation season by increasing rooting responses and increasing the sensitivity of stem cuttings to exogenously applied auxin. Chemical name used: 1H-indole-3-butyric acid (IBA).

Free access

Abstract

A modification of the traditional technique of etiolation and blanching, using Velcro adhesive fabric strips as the blanching material, was used with success in improving cutting propagation of a wide range of difficult-to-root woody species. Stockplants were etiolated under black cloth at budbreak, followed by banding for a period of 4 weeks, to produce a cutting with an etiolated base. Rooting of softwood cuttings from 18 of 21 species tested was improved significantly by these stockplant pretreatments. The use of Velcro as the banding material facilitated blanching, permitted the application of rooting hormone as a part of the blanching procedure, wounded underlying stem tissues, and resulted occasionally in the formation of adventitious roots on intact shoots.

Open Access