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  • Author or Editor: R.T. Poole x
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Codiaeum variegatum (L.) Blume `Petra' liners were transplanted into 15-cm pots and fertilized using 24N-3.4P-14.2K at a total of either 7.2 or 14.4 g N/pot over a 26-week growing period. Eight fertilizer treatments followed four application schedules at a low and high (double the low) rate. Schedules attempted to maximize fertilizer utilization with applications based on projected plant growth patterns. Irrigation was on an as-needed basis, and all leachate was collected from each pot. Weekly leachate per pot was analyzed for pH, electrical conductivity (EC), and NH4-N and NOx-N content. Plant and color grades, and height change were recorded and elemental tissue analyses done for each plant at experiment termination. Fertilizer rate and schedule affected height change, and pH and EC, as expected. Total mg NH4-N and NOx-N in the leachate increased with increased fertilizer rate. Fertilizer application schedule affected NH4-N content at the high fertilizer rate and NOx-N in the leachate at both fertilizer rates with the optimizing curve treatments leaching the least NOx-N for their respective fertilizer rates. Total mg N/pot (mg NH4-N + mg NOx-N) was significant for both fertilizer rate and schedule.

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Abstract

Excessive fertilization produces high soluble salts, resulting in root damage and poor quality foliage. Although usually determined by mixing soil with water, conductivity also can be determined by mixing with leachate obtained by pouring water through the potting medium.

Open Access
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Abstract

Trials in the greenhouse and growth chambers were performed to evaluate the influence of fertilizer level and temperature on sensitivity of Spathiphyllum cv. Clevelandii to acephate insecticide. Plant quality was not influenced consistently by fertilizer level in all tests, although highest-quality plants usually were produced with recommended fertilizer levels (3 g/15-cm pot Osmocote 19N-6P-12K). Plants were grown at fertilizer levels up to 15 g/15-cm pot with those grown between 22° and 27°C undamaged, while those grown at 32° had severe foliar necrosis and were stunted. Increases in either fertilizer level or temperature resulted in increased levels of phytotoxicity when plants were sprayed with recommended rates (0.4 g/liter) of acephate insecticide. An interaction occurred between temperature and fertilizer level in growth chamber trials.

Open Access
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Abstract

Peperomia obtusifolia (L.) A. Dietr. were grown with various fertilizer levels (0.5–3.5 g Osmocote 19-3-10/10-cm pot) and irrigation frequencies (1, 2, or 3 times/week). Plants were inoculated with Pythium splendens Braun 2–6 months after initiation of fertilizer treatments. Top and root quality responses were linear and quadratic with respect to fertilizer level. One month after inoculation, root quality decreased the most for plants with the highest irrigation frequency and the lowest fertilizer level. Plants fertilized at the highest rate did not show a significant decrease in root quality. There was an interaction between fertilizer and irrigation rates as measured by plant height, quality, and disease ratings. Poorest quality plants resulted when watered 3 times/week and fertilized with 0.5 g Osmocote/pot. Highest quality plants resulted when watered 2 or 3 times/week and fertilized with 2.5 g Osmocote/pot.

Open Access
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Abstract

Appearance of container grown Fiscus benjamina Linn. (weeping fig) and Brassaia actinophylla Pov. (schefflera), as measured by plant grade, density and leaf retention after 10 weeks under an interior environment, was improved over plants grown in full sun when plants were previously acclimatized under 40 or 80% shade for 5 or more weeks. There was also an increase in leaf retention as interior light supplied 12 hours/day 7 days a week, increased from 270 to 810 to 1350 lumens/m2.

Open Access
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Abstract

Leaf distortion of Aglaonema commutatum Schott ‘Fransher’ has been a common occurrence in commercial nurseries of Florida and elsewhere. New leaves arising from the apex were distorted, dwarfed and sometimes less than 4 cm long and 1 cm wide as opposed to normal leaves 20 cm long and 4 cm wide. Leaves sometimes had a slight curved, or hooked, appearance and edges rolled upward toward the center. Applications of copper (Cu) as a spray or drench reduced or eliminated leaf distortion.

Open Access
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Abstract

Dieffenbachia [Dieffenbachia maculata (Lodd) G. Don ‘Perfection’] were grown at 13° or 18.5°C minimum air temperature (AT) with constant soil temperature (ST) of 13.0°, 18.5°, 24.0°, or 29.5° and fertilized (FR) with 1.4, 2.8, or 4.2 g N/m2 per week from a 3N-1P-2K ratio stock solution. Data from experiments conducted during Winter 1981-82 and 1982-83 showed that air and soil temperatures had greater effects on plant growth than fertilizer rate. Interactions of AT and ST were highly significant for plant height, grade, number of basal breaks, and fresh top and root weights with plants produced at 18.5° AT better than 13° plants at low ST, but not at 29.5° ST. Quadratic responses of plants grown at 18.5° AT to increasing ST were similar to data obtained for tissue Ca and Mg, with lowest tissue levels occurring at the extremes of ST.

Open Access
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Abstract

Experiments conducted on Caladium bicolor Vent cv. Candidum have shown that apical bud removal increased number of shoots and decreased leaf length, height and color. Planting tubers inverted decreased grade, leaf length, height, and color. Increasing fertilizer level from 0 to 3.0 or 6.0 kg Osmocote/m3 had no influence on leaf size, but influenced grade, number of shoots, and leaf color. Interaction between fertilizer level and tuber orientation indicated higher nutrient levels were partly able to overcome deleterious effects of inverted placement, while interaction between apical bud removal and tuber orientation demonstrated negative effects of bud removal when combined with tuber inversion.

Open Access

Abstract

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.

Open Access

Abstract

Relatively few Dieffenbachia cultivars have become widely grown, although they have been important ornamental tropical foliage plants for many years. Most new cultivars have originated from private plant collections or by mutation from commercial cultivars, with breeding playing a minor role. A Dieffenbachia breeding program was initiated in 1976 at the Central Florida Research and Education Center at Apopka, which resulted in three previous cultivar releases (Henny et al., 1987a, 1987b, 1988). ‘Starry Nights’, herein described, is the fourth Dieffenbachia hybrid to be released from that program.

Open Access