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  • Author or Editor: James Barrett x
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Abstract

Chrysanthemum morifolium Ramat. plants were grown in media with and without pine bark and treated with drenches of α-cyclopropyl-α-(4-methoxyphenyl)-5-pyrimidinemethanol (ancymidol) at 0.25 mg/pot, (2RS,3RS)-l-(4-chlorophenyl)-4,4-dimethyl-2-(l,2,4-triazol-l-yl) pentan-3-ol (PP333) at 0.25 mg/pot, or α-(l-methylethyl)-α-[4-(trifluoromethoxy) phenyl]-5-pyrimidinemethanol (EL-500) at 0.0625 mg/pot, or two 5000 mg/liter foliar sprays of butanedioic acid mono-(2,2-dimethylhydrazide) (daminozide). Foliar sprays of daminozide controlled plant height equally in both media but drenches of ancymidol, PP333, and EL-500 were not effective when pine bark was included in the medium.

Open Access

A daminozide plus chlormequat chloride tank mix spray was applied to six Coleus cultivars or breeding lines at different times during propagation. For UF 03-8-10 and `Coco Loco', plants sprayed on day 7 or day 10 were shorter than control plants at transplant, but plants sprayed on day 13 were not. Other cultivars did not respond to single applications. Five of the six cultivars responded to application on days 7 and 13. Plants of UF 03-8-3 and `Coco Loco' were significantly shorter than control plants at transplant. Plants of UF 03-8-10, UF 03-6-1, and UF 03-17-8 were shorter than control plants at 3 weeks after transplant. `Hurricane Louise' did not respond to the tank mix. A second study found a cultivar specific response to three chemical treatments applied as a spray on day 10 of propagation. At transplant, UF 03-8-10, UF 03-8-3, UF 03-6-1, and `Coco Loco' plants sprayed with the tank mix at 2500 plus 1500 mg·L-1, respectively, were significantly shorter than the control plants. A uniconazole spray at 2 mg·L-1 reduced elongation in UF 03-8-10, UF 03-8-3, and UF 03-6-1, compared to control plants. Ethephon at 250 mg·L-1 reduced elongation in UF 03-8-10, UF 03-8-3, and `Coco Loco' plants. None of the chemical sprays reduced elongation in `Hurricane Louise' at the concentrations applied. Ethephon increased axillary branching in all cultivars, and induced lower leaf abscission in UF 03-17-8 and `Hurricane Louise'; leaf malformation in UF 03-6-1 and `Coco Loco'; and color alteration in UF 03-6-1, UF 03-8-3, and `Coco Loco'.

Free access

The paclobutrazol liner dip is a plant growth regulator application technique that is becoming widespread in the commercial bedding plant industry. This technique, in which plug trays are dipped in a solution of paclobutrazol before transplant, is an efficient method for applying this growth regulator to a large number of plants. In previous studies, significant variability in size control was documented following liner dip treatments with identical solution concentrations. To elucidate the causes of this variability, three bedding plant species with varying levels of paclobutrazol sensitivity (Petunia ×hybrida, Impatiens wallerana, and Scaevola aemula) were treated with paclobutrazol liner dips under various conditions. Four factors identified in previous studies that may impact the efficacy of paclobutrazol liner dips were evaluated in this study. The age of the cuttings at the time of treatment ranged from 2 to 4 weeks after propagation. The light intensity incident to the plants from 2 h before through 2 h following the time of treatment ranged from about 1000 μmol·m-2·s-1 in a greenhouse to 5 μmol·m-2·s-1 indoors. The relative moisture content of the plug media before the treatment was saturated or at 25%, 50%, or 80% dry down by weight, based on air-dried media. The amount of time the plug media remained in the paclobutrazol solution was 10 s, 30 s, or 2 min. Data were collected on stem elongation 3 weeks after transplanting and again 2 weeks later. The results confirm that all four factors tested interact with the concentration of paclobutrazol in the dip solution to determine the control in stem elongation achieved by the treatment.

Free access

Abstract

‘Gutbier V-10 Amy’ (‘Amy’) poinsettia lost more leaves and cyathia after simulated shipping at different temperatures (4°, 16°, or 24°C) and 30 days under interior conditions than ‘Annette Hegg Dark Red’ (‘AHDR’) plants. ‘Amy’ and ‘AHDR’ plants lost a large number of leaves when shipped for more than 4 days at 24°. ‘Amy’ quality was reduced when shipped at 4° due to chilling injury (white lesions on bracts). Bracts less than 2.5 cm long were most sensitive to this injury.

Open Access

Abstract

A 2 pine bark : 1 moss peat: 1 sand (by volume) medium (11% volumetric, 20% gravimetric moisture) amended with 4.2 kg m −3 of dolomitic limestone and 3 kg m−3 of 32P-, 35S-superphosphate (8.7% P, 11.7% S) was incubated (25°C) for either 0, 15, or 30 days. Columns (4 × 15 cm) of the medium for each incubation time received 48 ml of deionized water (pH 5.5) in 3 hr on day 1 and 16 ml in 1 hr on days 2-21. Forty-six and 21% of 32P and 35S, respectively, leached on day 1 when the medium was not incubated. Thirty-one percent and 28% of the 32P and 14% and 13% of the 35S leached on day 1 if the medium had been incubated 15 or 30 days, respectively. Eighty-two percent of the 32P and 66% of the 35S amendment leached from the unincubated medium during the 3 week experimental period. A similar leaching experiment, but with superphosphate in absorbent cotton instead of the soilless medium, indicates superphosphate dissolves readily.

Open Access

Abstract

‘Gutbier V-14 Glory’ poinsettia was introduced to the commercial industry in the late 1970s and has been shown to be sensitive to bract necrosis (3). Necrotic spots occasionally develop on the intermediate bracts during the latter parts of the crop cycle. Nell and Barrett (2) found this problem to be worse when plants were provided 300–400 mg/liter Ν at every irrigation and well watered during bract coloration. Symptoms resembled injury due to elemental toxicity or desiccation. Observations in commercial operations suggested that necrosis may be related to fertilizer source or formulation.

Open Access

Abstract

Research indicates P and S leach rapidly from soilless media amended with ordinary superphosphate (2). Since these elements are in the form of anions, an amendment with a high anion exchange capacity may reduce their leaching from soilless media. In the following study, an anion exchange resin was used to test this theory.

Open Access

Abstract

Columns of an incubated (25°C, 11% volumetric moisture for 30 days) 2 milled pine bark : 1 Canadian sphagnum peat : 1 builders’ sand (by volume) medium amended with the equivalent of 270 g P·m−3 from radioactive superphosphate (8.7% P) and the equivalent of 0, 33, 200, or 1200 g Al·m−3 from aluminum acetate (13.2% Al) were leached daily with 16 ml deionized water. Eighty percent of the 32P amendment leached during days one to 21 from the medium not amended with Al, whereas 0.3% leached when amended with 1200 g Al·m−3. Leachate 32P levels ranged from 840, 711, 91, and 2.0 μg·ml−1 on day 1 to 2.3, 3.3, 7.6, and 0.9 μg·ml−1 on day 77 for the medium with Al amendments of 0, 33, 200, and 1200 g·m−3, respectively.

Open Access

Bedding plant seedlings were obtained as plugs from commercial sources, transplanted into 10-cm pots, and grown using standard commercial procedures. When plants reached a marketable stage, they were treated with Hydretain, moved to a heavy shaded bench in the greenhouse, and time to first wilt was determined. At wilt, plants were given 180 ml of water, and time to second wilt was observed. Hydretain was applied directly to the media in a volume of 90 ml per pot. Hydretain dilutions in water were 1:4, 1:9, 1:14, 1:19, and 0:1 (controls). Time to first wilt in 'Red Elite' geraniums was 11, 10, 9, 10, and 5 days, respectively. For 'Little Bright Eyes' vinca, first wilt was in 7, 8, 5, 5, and 4 days; and time from treatment to second wilt was 18, 14, 11, 10, and 8 days, respectively. For 'Super Elfin Red' impatiens, first wilt was in 5, 4, 4, 3, and 3 days; and the water absorbed was 121, 167, 172, 132, and 148 ml, respectively. Second wilt was in 7, 7, 8, 5, and 5 days, respectively.

Free access

Impatiens L. wallerana Hook., Salvia splendens Sello ex Nees, Tagetes erecta L., and Petunia hybrida Vilm. plants in 610-cm3 pots were sprayed with either uniconazole or paclobutrazol at concentrations from 10 to 160 mg·liter-1. For all species, both chemicals reduced plant size compared with untreated control plants, and the effect increased with higher concentrations. Uniconazole produced smaller plants than did paclobutrazol at similar concentrations. For impatiens, salvia, and marigold, there was an interaction between chemical and concentration; the degree of difference between the effects of the chemicals was greater at higher concentrations. For these three species, uniconazole elicited a quadratic response and reached saturation within the concentrations used; however, these concentrations were still in the linear portion of the dose response curve for paclobutrazol. Chemical names used: (2RS,3RS)-1-(4-chlorophenyl)-2-(1,1-dimethylethyl)-(1H-1,2,4-triazol-1-yl)pentan-3-ol (paclobutrazol); (E)-(+)-(S)-1-(4-chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)-pent-1-ene-3-ol (uniconazole).

Free access