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David G. Clark, John W. Kelly, and Nihal C. Rajapakse

The effects of carbon dioxide enrichment on growth, photosynthesis, and postharvest characteristics of `Meijikatar' potted roses were determined. Plants were grown in 350, 700, or 1050 μl CO2/liter until they reached 50% flower bud coloration and then were placed into dark storage for 5 days at 4 or 16C. Plants grown in 700 or 1050 μl CO2/liter reached the harvest stage earlier and were taller at harvest than plants produced in 350 μl CO2/liter, but there were no differences in the number of flowers and flower buds per plant among CO2 treatments. Plants grown in early spring were taller and had more flowers and flower buds than plants grown in late winter. Shoot and root growth of plants grown in 700 or 1050 μl CO2/liter were higher than in plants produced in 350 μl CO2/liter, with plants grown in early spring showing greater increases than plants grown in late winter. Immediately after storage, plants grown in 350 μl CO2/liter and stored at 4C had the fewest etiolated shoots, while plants grown in 1050 μl CO2/liter and stored at 16C had the most. Five days after removal from storage, chlorophyll concentration of upper and lower leaves had been reduced by ≈50% from the day of harvest. Carbon dioxide enrichment had no effect on postharvest leaf chlorosis, but plants grown in early spring and stored at 16C had the most leaf chlorosis while plants grown in late winter and stored at 4C had the least leaf chlorosis.

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Shannon E. Beach*, Terri W. Starman, and H. Brent Pemberton

Bracteantha bracteata (Vent.) Anderb. & Haegi (bracteantha) is a vegetative annual produced as a 12.7-cm potted plant in 6 weeks of greenhouse production. A dense leaf canopy produced with a conventional constant-feed fertilization regime (300 mg·L-1 20N-4.4P-16.6K) caused increased disease pressure and lower leaf chlorosis during greenhouse production. During shelf life, lower leaves of plants con-tinued to become chlorotic. The objective was to decrease leaf area and prevent lower leaf chlorosis without affecting harvest time, plant quality or shelf life of two cultivars of three series of bracteantha. The first experiment was to reduce the rate of fertilizer two weeks prior to harvest. Treatments were no fertility reduction (300 mg/liter), 50% reduction (150 mg/liter), and 100% reduction (0 mg·L-1). At harvest, plants were evaluated for shelf life in a growth room at 21.1 ± 1.3 °C and 6 μmol·m-2·s-1 PPF. Five cultivars in the 100% fertility reduction treatment had decreased height and/or width index at harvest and three cultivars maintained higher postharvest quality ratings compared to the other treatments. Separately, the effect of the duration of fertilization was evaluated by terminating fertilization at weekly intervals (0-6 weeks) throughout production. Ceasing fertilization two to three weeks prior to harvest produced plants with lower leaf area without affecting flower number. In another experiment, thidiazuron (TDZ) as a foliar spray at 0, 0.1, 0.5, and 1.0 mg·L-1 was applied to decrease lower leaf yellowing. SPAD-502 chlorophyll meter readings of lower leaves were increased with 0.1 mg·L-1 TDZ treatment compared to the control. Phytotoxic symptoms occurred on plants receiving higher TDZ rates.

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Garry J. Bradley, Mari Helen Glass, and Ted E. Bilderback

With the rising cost of sphagnum peat, nurserymen are looking at alternatives for growing substrates. Daddy Pete's plant pleaser is a product of composted cow manure. This study was conducted to see if composted cow manure could be used to grow containerized plants and replace sphagnum peat. Research was conducted using two Rhododendron cultivars, `English Roseum' and `Scintillation'. Plants of each cultivar were potted into 3-gallon containers. Test substrates were tested against the grower's standard mix, 80 pine bark: 20 sphagnum peat (% by volume), amended with 20 lbs Scotts Prokoke, 8 lbs dolomitic limestone, and 1.5 lbs step minor element package/1.7 yard3. Test substrates were treated equally. Daddy Pete's plant pleaser can work as a substitute for peatmoss in a growing mix. The Daddy Pete compost grew just as good a plant as the Buds & Bloom standard. Watering management turns out to be a factor because the compost generally held more water, therefore not needing irrigation as frequently.

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Fabienne Gauthier, Blanche Dansereau, and Serge Gagnon

During Spring–Summer 1994, seedlings of Impatiens walleranc `Accent Coral' and Pelargonium × hortorum `Orbit Hot Pink' were grown in a commercial substrate (PRO-MIX BX) or in one of two substrates composed of six organic residues (composted water treated sludge, forestry compost, fresh or composted used peat extracted from a biofilter during treatment of municipal water, and fresh or composted paper sludge). These residues were incorporated with peatmoss and perlite at 5%, 10%, 25%, and 40% by volume to obtain the 24 substrate combinations. Plants were watered and fertilized by flooding ebb-and-flow benches. Growth measurements (growth index, top and root dry weight, number of flowers and buds, visual quality) varied considerably depending or the percentage of residue incorporated into the substrates. Moreover, substrates containing 40% of organic residues are not recommended for the production of impatiens and geraniums.

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Mark V. Yelanich, James E. Faust, Royal D. Heins, and John A Biernbaum

The measurement of evaporation and transpiration from container-grown crops is labor intensive and expensive if measurements are made by periodic weighing of the plants with electronic scales. Thin-beam load cells (LCL-816G, Omega Engineering) measured with a datalogger provides a method of making continuous mass measurements over time. Four load cells were tested to determine the feasibility for use in greenhouse studies. The sensors were calibrated to an electronic scale at a range of air temperatures. The electrical signal (μV) was a linear function of mass from 0 to 816 g. The change in mass per change in electrical signal (i.e. the slope) was the same for all four load cells (1.26 g ·μV-1), however the absolute electrical signal (the intercept) was unique for each sensor (-246 to + 101 g). The effect of temperature on sensor output was unique for each sensor in terms of both the magnitude and direction of change. A two-point calibration of mass performed at a range of temperatures is required to properly use thin-beam load cells to continuously measure evapotranspiration of container-grown crops.

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Alicain S. Carlson, John M. Dole, and Brian E. Whipker

control growth of pineapple lily, but Filios and Miller (2013) found paclobutrazol (4.0 and 8.0 mg/pot) and flurprimidol (2.0 mg/pot) to be effective in controlling height of ‘Innocence’ and ‘Tugela Ruby’ pineapple lily ( Eucomis comosa ). Substrate

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Kaitlin Barrios and John M. Ruter

, with Dasoju et al. (1998) finding paclobutrazol at 2 mg/pot as a substrate drench on potted sunflower ‘Pacino’ reduced height by 17% to 25%. Similar responses from a similar application of paclobutrazol were obtained by Whipker and McCall (2000) on

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Brian A. Krug, Brian E. Whipker, and Ingram McCall

(excluding the pot) would be considered commercially acceptable ( Barrett et al., 1995 ). Paclobutrazol (Bonzi; Syngenta, Greensboro, N.C.) substrate drench recommendations vary from 8 mg·L −1 ( Dole and Wilkins, 2005 ), 0.5 to 1 mg/pot a.i. ( Barrett et al