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  • Author or Editor: T. A. Nell x
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Several pulse solutions were tested for their effectiveness in preventing leaf senescence on four cut oriental lily cultivars (Lilium sp. `Acapulco', `Kissproof', `Noblesse' and `Star Gazer'). Stems were pulsed 24 hours after harvest for 1 hour, stored in boxes in the dark for 5 days at 3 °C (37.4 °F) then evaluated in postharvest conditions. A new commercial product called Chrysal BVB, a proprietary mixture manufactured by Pokon & Chrysal (Miami) containing cytokinine and gibberellic acids, was the most effective product tested. Chrysal BVB [1 mL·L–1 (0.1%)] prevented leaf chlorosis and abscission on `Acapulco' and `Noblesse' and significantly reduced it by 82% on `Star Gazer' and by 69% on `Kissproof'. Stems pulsed in Fascination, a commercial mixture containing 1.8% gibberellins (GA4+7) and 1.8% benzyladenine [5.4 mg·L–1 (ppm) each], virtually prevented leaf chlorosis on `Noblesse', reduced it by 50% or more on `Acapulco' and `Star Gazer', and significantly delayed it 8 days on `Kissproof'. A 10 μm (2 ppm) pulse in thidiazuron, a substituted phenylurea with cytokinin-like properties, delayed leaf chlorosis on `Star Gazer' but to a lesser extent compared to BVB and Fascination. Chrysal SVB, a propri-etary mixture manufactured by Pokon & Chrysal containing gibberellic acid, had no effect on reducing leaf chlorosis on `Star Gazer'. None of the pulse solutions had adverse effects on bud opening, flower quality or vase life. Maintaining stems in a bulb flower preservative significantly reduced leaf chlorosis and abscission in all cultivars when stems were not pretreated with a pulse solution or when a pulse solution was ineffective.

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Brassaia actinophylla Endl., Chamaedorea elegans Mart., Dieffenbachia maculata (Lodd.) G. Don ‘Exotica’, Dracaena marginata Lam., and Ficus benjamina L. were grown for 1 year under 13 or 26 μE m−2sec−1 from Cool White fluorescent lamps for 12, 18, or 24 hours daily durations. Increasing light duration to 24 hours daily decreased quality of all plants tested, with Brassaia, Chamaedorea, and Dieffenbachia being most affected. The primary symptoms resulting from constant light were foliar chlorosis and decrease in plant quality, although necrotic spotting appeared at times. By experiment termination, best plants overall were associated with 26 μE m−2sec−1 light for 12 or 18 hours duration and poorest with 26 μE m−2sec−1 light and 24 hours duration. A second factorial experiment with Dieffenbachia and Dracaena tested effects of 3 fertilizer levels (0, 0.67, or 1.30 g Osmocote/3 months per 15-cm pot) under 2 light intensities (13 or 26 μE m−2sec−1) and 2 light durations (12 or 24 hours) on plant quality. Higher fertilizer levels had a limited effect on plant quality, while influence of light intensity and duration was similar to the initial experiment.

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Abstract

Lateral budbreak was increased significantly on ‘Welkeri’ dieffenbachia [Dieffenbachia maculata (Lodd.) G. Don] with foliar applications of 6-benzylamino purine (BA) at 500,1000, and 2000 mg/liter. Sodium 2,3:4,6-bis-0-(1-methylethylidene)-a-L-xylo-2-hexulofuranosonic acid (dikegulac) at 1000, 1500, and 2000 mg/liter and (2-chloroethyl)phosphonic acid (ethephon) at 500, 1000, and 2000 mg/liter had no effect on branching. Plant height was unaffected by application of growth regulators although moderate foliar necrosis was caused by the highest rate of BA.

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Abstract

Fresh, unfixed meristems of rose (Rosa hybrida L.) were viewed in the scanning electron microscope to determine the morphological differences and organogenesis of flowering and blind shoots. Gluteraldehyde fixed, ethanol dehydrated and critical point dried tissue was severely desiccated with individual cell walls becoming concave. Fresh tissue remained turgid for at least 10 min in the microscope. Visible signs of flower initiation were evidenced by the presence of sepal primordia followed by differentiation of petals, anthers and stigma. No evidence of flower initiation was observed in the blind shoot.

Open Access

Abstract

‘Tropicana’ rose plants (Rosa hybrida L.) were exposed to increasing periods of high intensity light (640 W/m2) beginning immediately after flower removal, in the fall and winter of 1975 and spring and summer of 1976. Flowers were also removed from ‘Forever Yours’ and ‘Cara Mia’ plants in the summer of 1976 and shoot length, stem diameter and bud diameter were evaluated as morphological indicators of blind shoot development. Plants were transferred to a growth chamber (300 W/m2) following the high intensity lighting treatment. Plants grown in the growth chamber without supplemental lighting had the highest percentage of blind shoots. Maximum blindness occurred during the winter months regardless of lighting treatments. Blind shoot production decreased with increased duration of supplemental lighting. Shoot length proved to be an effective indicator of blind shoots as early as 10 days following lateral bud initiation on all cultivars. The value of bud diameter and stem diameter as indicators of blindness was dependent on cultivars.

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Abstract

Foliar spray applications to ‘Gloria’ azalea (Rhododendron obtusum) of daminozide, chlormequat chloride, daminozide/chlormequat chloride combination, ancymidol, paclobutrazol, fluometralin, NAA, and IBA were applied prior to bypass shoot development. All treatments except IBA reduced bypass shoot length. NAA treatments were phytotoxic, and fluometralin inhibited flowering. Rate of flower development was retarded by daminozide, chlormequat chloride, and daminozide/chlormequat chloride combination, but was unaffected by ancymidol, paclobutrazol, fluometralin, NAA, and IBA. Paclobutrazol was the most efficient and effective treatment in reducing bypass shoot length without affecting flower size or time to flower. Chemical names used: butanedioic acid mono (2,2-dimethylhydrazide) (daminozide); 2-chloro-N,N,N-trimethyl-ethanaminium chloride (chlormequat chloride): α-cyclopropyl-α-(4-methoxyphenyI)-5-pyrimidinemethanol (ancymidol): β,[(4-chlorophenyl)methyl)-α-(1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol (paclobutrazol): 2-chloro-N-[2,6-dinitro-4-trifluoromethyl)phenyl]-N-ethyl-6-fluorobenzenemethanamine (fluometralin): 1-naphthaleneacetic acid (NAA): 1H-indole-3-butyric acid (IBA).

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Abstract

‘Minetto’ lettuce seeds (Lactuca sativa L.) were germinated at 35°C after different initial imbibition periods at 20°. No germination occurred at 35° in untreated seeds when the imbibition period was less than 6 hours. Maximum germination occurred after the seeds were imbibed for 16 hours. Most seeds primed in 1% K3PO4 at 15° for 9 hours then redried, germinated at 35°. However, germination increased gradually by increasing the time of early imbibition exposure to 9 hours. The endosperm membrane of seeds primed for 9-18 hours in a 1% K3PO4 solution did not rupture. Rupture of the membrane was evident after 21 hours of priming. A progressive loosening of the membrane after 9 hours of priming may be indicative of membrane weakening, possibly enhancing seed germination at high temperature.

Open Access

Bract edge burn (BEB) is a serious commercial problem, and a cooperative trial with six cultivars was conducted at the above research locations and in commercial greenhouses in the respective areas. `Success' and `21-91' had less BEB than `Celebrate 2', `V-14 Glory', or `Supjibi'. BEB symptoms increased with time during postproduction. Number of bracts with BEB spots on `V-14 Glory' at boxing, unboxing, 7 and 14 days were 1, 3, 6, and 10, respectively. Weekly Ca sprays (400 ppm at start of color) reduced or prevented BEB in the greenhouse at all locations where BEB developed and reduced the development in BEB during postproduction. BEB increased with fertilizer level and was higher in plants with elevated potassium or ammonium. These effects were reversed by Ca sprays. BEB was increased by boxing wet plants or inoculating plants with Botrytis. BEB was reduced by boxing dry plants, fungicide treatment, or terminating fertilization. BEB symptoms for different cultivars will be presented.

Free access

Abstract

Plant size, and number of flowers of chrysanthemums (Chrysanthemum ×morifolium Ramat. cvs. Yellow Mandalay and Royal Trophy) were reduced when grown in a soil containing granular α-cyclopropyl-α-(4-methoxyphenyl)-5 pyrimidine (ancymidol) or provided ancymidol drench or butanedioic acid mono-(2,2-dimethylhydrazide) (daminozide) spray but not when sprayed with ancymidol (0.5 mg). Granular ancymidol at 0.5 mg/pot reduced plant height 9% on ‘Yellow Mandalay’ and 30% on ‘Royal Trophy’ compared to controls. Foliar applications of daminozide reduced height 27% on ‘Yellow Mandalay’ and 47% on ‘Royal Trophy’.

Open Access

Abstract

A granular formulation of ancymidol [α-cyclopropyl-α-(4-methoxyphenyl)-5pyrimidine] was compared to ancymidol and chlormequat [(2-chloroethyl) trimethylammonium chloride] drenches for height control of multi-branched poinsettias (Euphorbia pulcherrima Wild.) grown in 10 cm diameter pots. Granular ancymidol at 0.125 mg ai/pot retarded plant growth with no retardation in bract diameter. Granular ancymidol at 0.25 mg ai/pot was as effective as 0.5 mg ancymidol applied as a drench and produced the ideally proportioned plants. All ancymidol treatments were more effective in height retardation than chlormequat applied at 240 mg ai/pot. Bract diameter was reduced in all ancymidol treatments and 0.5 mg ai/pot.

Open Access