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  • Author or Editor: George J. Wulster x
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Abstract

A method is described for obtaining nondestructive estimates of root system surface area. The technique is based on the assumption that the larger the root system, the more gel of a given viscosity will adhere to it. The correlation between gel adherence and 5 parameters of root system size (root length, root fresh weight, root dry weight, root volume, and root surface area) is established.

Open Access

Abstract

In the article “A Nondestructive Method for Measuring Root System Surface Area” by George J. Wulster (HortScience 20:1058–1060, Dec. 1985), the author requests that the following correction be noted: The 3rd line under Gel Construction on p. 1058 should be changed from “… HHR (0.65gm/l) was added slowly to 2 liters … ” to “… HHR (0.65 gm/100 ml) was added slowly to 2 liters …”.

Open Access

A software application for the personal computer has been developed using the macro languages of Lotus l-2-3 Release 2.2 and the spreadsheet compiler Baler XE Release 1.0E to provide Easter lily (Lilium longiflorum Thunb.) growers with a tool to track and predict various developmental stages of the crop during greenhouse forcing.

Full access

Growth and flowering of Freesia hybrida Bailey for the container-plant market can be controlled chemically using growth retardants and environmentally by cold storage of corms at 5C for 2 to 6 weeks before planting. Corms stored at 5C for 4 weeks flowered 20 days earlier than corms not stored at 5C. Preplant 5C storage of corms also reduced leaf and flower height. An ancymidol soil drench (3 mg) reduced leaf height and flower height by more than 50% and delayed flowering by 9 days. Combining growth regulator application with cold storage of corms produced the greatest reduction in leaf height and flower height. Moreover, plants flowered earlier than controls when corms were stored for at least 4 weeks, regardless of growth regulator treatment. Chemical name used: α-cyclopropyl-α- (4-methoxyphenyl) -5-pyrimidine methanol (ancymidol).

Free access

Growth and flowering of Ixia hybrids as potted plants can be controlled environmentally by cool preplant storage of corms, regulation of greenhouse forcing temperatures, and application of a growth retardant. Paclobutrazol applied as a preplant corm soak, a postemergent drench, or a postemergent spray in combination with a 2- to 4-week preplant storage of corms at 7 °C, and an 18 °C day/10 °C night forcing temperature produced attractive and marketable plants. Chemical name used: β-[(4-chlorophenyl)methyl]-α-(1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol (paclobutrazol, Bonzi®).

Free access

Growth and flowering of Ixia hybrids as potted plants can be controlled environmentally by cool preplant storage of corms, regulation of greenhouse forcing temperatures, and application of a growth retardant. Paclobutrazol applied as a preplant corm soak, a postemergent drench, or a postemergent spray in combination with a 2- to 4-week preplant storage of corms at 7 °C, and an 18 °C day/10 °C night forcing temperature produced attractive and marketable plants. Chemical name used: β-[(4-chlorophenyl)methyl]-α-(1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol (paclobutrazol, Bonzi®).

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A silver thiosulfate (STS)-mediated increase in pathogen susceptibility was investigated using shoot cuttings from stock plants of pelargonium (Pelargonium hortorum Bailey cv. Ringo Scarlet) with and without STS treatment. Callusing and rooting were reduced in shoot cuttings from ST&treated plants. The pathogen-tolerant tissue (no STS) was shown to produce enhanced levels of phenolic esters and glycosides during wound healing. Reactivity to the histochemical stain phloroglucinol-HCL was also enhanced during wound healing in cuttings from plants that had not received a silver treatment.

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Hybrid lilies(4 oriental & 2 asiatic) species were grown in commercial potting media formulations containing various percentages of composted bark. Lilies were grown in greenhouse sections maintained at either 21C day temperature and 15C night temperature or 15C day temperature and 21 C night temperature from emergence until anthesis. The growth retardants Paclobutrazol (Bonzl) and Uniconazole (Sumagic) were applied as a media drench at 0.25 mg a.i. per pot. Final height, days to flower from planting, days to flower from visible bud, and flower number were recorded for each treatment. Plant height was significantly reduced by potting media formulation, growth retardant treatment, and temperature regime. The effects of these treatments on bud number, and days to flower will also be discussed.

Free access

Easter Lilies (Lilium Longiflorium) were grown in potting media containing 50% peatmoss and 50% vermiculite V/V or amended with 25, 33, or 50% (V/V) composted municipal sludge.

Macro and micro nutrient levels were determined for the various media formulations using either a water or a Mehlich III extraction procedure. Foliar levels of micro and macro nutrients were determined at anthesis. Final plant height and number of buds per plant were measured for each treatment.

No media formulations were phytotoxic; however, several micro element levels increased with increasing composted sludge content in foliar samples. These increasing foliar levels of Cu, Fe, Zn correlated well with media levels when Mehlich III was the extraction method. A similar correlation was not found with water as the extractant.

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Phenylglyoxal (PGO) a chemical modifier of arginine residues inhibits nitrate (NO- 3) uptake by corn roots. It has been proposed that the NO- 3 uptake system in corn has essential arginyl residues in or near the NO- 3 binding site. PGO was used to evaluate NO- 3 uptake by Poinsettia roots. Inhibition of NO- 3 uptake was observed using three levels of PGO (0.25, 0.5, 1mM). Root plasma membrane vesicles were isolated and used in uptake experiments to determine if PGO was interacting with the NO- 3 uptake system located in that membrane. 35CIO- 3 which is a NO- 3 analog, accumulated only in the vesicles that were not treated with PGO.

Free access