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  • Author or Editor: J.W. White x
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Abstract

With 4 weeks of long nights Kalanchoe ‘Deep Scarlet’, ‘Yellow Darling’ and ‘Exotica’ reached maturity by the 10th week from sowing; ‘Melody’ on the 14th week; with 6 weeks of long nights ‘Morning Sun’ on the 10th week, ‘Ramona’ on the 12th week and ‘Red Glow’ >14 weeks. Response time, defined as days from the beginning of long nights to anthesis, was 13 weeks for ‘Hummel's Hybrid’ and ‘Ramona’; 9 for ‘Deep Scarlet’; 10 for ‘Yellow Darling’, ‘Exotica’, and ‘Morning Sun’; 11 for ‘Melody’; and <12 weeks for ‘Red Glow.’

Open Access
Authors: and

Abstract

Continuous, 24 hour, supplementary lighting of ‘Red American Beauty’ roses with W.S. GRO-LUX fluorescent lamps at 16 lamp watts/foot2 significantly increased flower yields and quality without significantly reducing flower Stem length, weight, or node number. Similar results were obtained with 4 NH4 + to NH3 -N ratios when the plants were grown at low moisture stress in either Lelite sand alone or a 50-50 V/V mixture of Lelite sand and sphagnum moss peat. However, the highest yields were obtained from plants grown in Lelite and peat receiving either 71.4 or 57.1 % of the N as NO3 .

Open Access
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Abstract

Osmotic stress produced the shortest plant with smallest bracts of Euphorbia pulcherrima Klotzsch. Soil drenches with 3000 ppm chloromequat [(2-chloroethyl)trimethylammonium chloride] or 0.25, 0.50, 0.75 or 1.00 mg ancymidol (alpha-cyclorproylalpha, para-methoxyphenyl, 5-pyrimidineme-thanol) per 15 cm pot were the most effective chemical methods of poinsettia height control. Metering either chemical into the irrigation-fertilization system also showed promise. Foliar sprays with ancymidol at 45, 90, 135 or 180 ppm were the least effective in controlling the height of ‘Eckespoint Cl Red’ or ‘Dark Red Annette Hegg’ poinsettias.

Open Access
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Abstract

Plants of Chrysanthemum morifolium Ramat. grown on a constant fertilization program were analyzed for elemental content, and the growing mix was analyzed by 3 different soil test methods. Optimum values for the nutrients reported by each of the soil tests were determined by using plant uptake data.

Open Access

Abstract

‘Red Elite’ hybrid geraniums were grown in controlled environment rooms and greenhouses with 109 combinations of daily light integrals (DLI) ranging from 9 to 25 mol·day−1·m−2 and daily mean temperatures (DMT) from 13.5° to 22.5°C. The time between seedling emergence and macrobud did not change significantly until the DLI was < 13 mol·day−1·m−2 (at 18° DMT). Flowering will not occur below a DLI of 3.3 mol·day−1·m−2. The time between emergence and macrobud progressively decreases as DLI increases until a DLI of close to 13 mol·day−1·m−2 is reached, and with increases in DLI above ≈17 mol·day−1·m−2 there is virtually no increase in the developmental rate of flower buds to the macrobud stage. Rate of development response of ‘Red Elite’ to temperature over the 9° to 27° range was curvilinear. DMT had more influence that DLI between 14 and 25 mol·day−1·m−2 on the time of flower development from macrobud to anthesis. The rate of development response over the 13° to 27° range was linear, and a heat sum relationship could be used to predict flowering. Increased DMT reduced the time between sowing and flowering with consequent reduction in dry weight and flower and bud numbers.

Open Access

Abstract

“Red Elite” geraniums were grown from the 6th leaf stage until the visible bud stage in controlled environment (CE) chambers under 3 day/night temperature regimes (27°/13°, 23°/17°, or 20°/20°C) and under enhanced CO2 (900 μl CO2/liter air) at 27°/13°. Three daily light integral treatments, 24.6, 19.8, and 15.1 mol m−2 d−1, were imposed over each of these 4 treatments. Plants also were grown in a 22714° glasshouse with 2 daily light integral treatments (18.2 or 11.3 mol m−2 d−1). A chlormequat (CCC) drench was applied to half of the plants immediately before the treatments were started. For the period between the 6th leaf and visible bud stages, leaf area, leaf area ratio, specific leaf weight, shoot dry weight, leaf canopy height, and time to visible bud were determined mostly by daily mean temperature rather than by day or night temperature. Most plant growth characteristics, but not the flower bud development rate from 6th leaf to visible bud, were enhanced by supplemental CO2 and suppressed by CCC. After reaching the visible bud stage, plants from some treatments were moved into 24715° CE temperature conditions with or without CO2, whereas others were moved to a glasshouse until harvest at the 1st floret anthesis stage. Between visible bud and anthesis, CCC was the major factor affecting vegetative growth regardless of whether the plants were with or without supplemental CO2 in CE rooms, or in a glasshouse. Anthesis was delayed by about 10 days in the glasshouse compared to the CE treatments but was unaffected by CO2 or CCC treatments. Carbohydrate concentrations were highest (starch 14%, sugar 5%) in plant leaves grown with supplemental CO2 and without CCC, and lowest with no added CO2 but with CCC in all CE treatments. The concentrations were reduced (starch 0.5%, sugar 2.5%) in plant leaves grown in a glasshouse from 6th leaf stage to anthesis because of low daily light integrals and no supplemental CO2.

Open Access

Abstract

Seedlings (72 or 48 days old) of Pelargonium × hortorum cv. Red Elite were grown in 1 experiment from the 6th leaf stage in controlled-environment (CE) rooms at 4 temperatures, including 2 split-night (SN) regimes and at 3 daily-light integrals; in a 2nd experiment they were grown at 2 temperatures including one SN regime, at 3 daily-light integrals, and with and without chlormequat soil drench. Each of the 2 night-temperature periods were of equal duration in the SN regimes. Plants grown under the SN regimes were either similar in growth and reproductive development to plants grown under constant night conditions, where the temperature was the mean of the 2 SN temperatures, or were generally intermediate in growth and development to plants grown throughout the night at each of the 2 temperatures used in the SN regime. A daily mean temperature of 20°C compared to 16.8° or 18° reduced the time between the 6th leaf and macrobud visible stages by 8 days. Leaf starch and sugar levels decreased as mean daily temperatures increased, but increased as daily-light integrals increased. Drenches of (2-chloroethyl)-trimethylammonium chloride (chlormequat) applied at the 6th leaf stage limited plant height and leaf area without influencing flowering date.

Open Access
Authors: and

Abstract

Geranium (Pelargonium × hortorum Bailey ‘Red Elite’) seedlings were grown with five daily mean temperature (DMT) and daily light integral (DLI) treatment combinations: DMT of 23°C/day at DLI of 8.64 mol·day−1·m−2 (TI), DMT of 25° at 8.64 mol (T2), DMT of 23° at DLI of 17.28 mol, (T3) DMT of 25° at DLI 17.28 mol (T4), and DMT of 21° at 17.28 mol (C1). Using infrared thermometry to control leaf temperature, DMT had a greater influence on flower initiation at the transition stage and on flower bud development to macrobud stage than DLI. Seedlings in T4 reached transition stage 24 days after sowing with a cumulative irradiance of 415 mol. Transition occurred in T1 at 27 days from sowing, with a cumulative irradiance of only 233 mol. Some time after 27 days from sowing, transition occurred in T2, T3, and C1. With a DLI of 17.28 mol, a DMT reduction from 25° to 23° to 21° effected macrobuds in 42, 56, or 62 days after sowing, respectively; whereas with a DLI of 8.64 mol, a decrease from 25° to 23° effected macrobuds in 54 or 51 days.

Open Access
Authors: and

Abstract

Nine bedding plant vegetable and flower cultivars were grown in each of 10 night air and root media temperature regimes. Generally, fresh and dry weights were greater at 16°C than at 7° night air temperature when root-zone (RZ) heating was not used. Soil warming increased fresh and dry weights of all cultivars grown at 16° night air temperatures. When air temperatures were below 16°, soil warming maintained fresh and dry weights equivalent to or better than plants grown at 16° without soil warming. Two split-night (SN) air temperature regimes were as effective as a constant 16° night temperature, ranking first and 3rd in fresh and dry weight per unit of energy consumption. All soil warming treatments had higher energy productivity than the 16° air temperature treatment with no RZ heating.

Open Access

Abstract

The time between sowing and flowering (crop cycle) of geranium Pelargonium × hortorum Bailey was affected by light, temperature, chloromequat chloride (CCC), and cultivar. A minimum daily light integral of 17 mol·d−1·m−2, provided by high-pressure sodium lamps (HPS) prior to transplanting, accelerated flower initiation. HPS, low pressure sodium (LPS), and metal halide (MH) lamps, used as supplemental light after transplanting, reduced the crop cycle significantly compared to incandescent (INC) or natural light only. Crop cycles were similar among the HPS, LPS, and MH lamp treatments when equal-input lamp wattage was used per unit growing area, even though PPF values at the plant canopy varied. Plants grown at 21° and 27°C had a 5- to 15-day-shorter crop cycle than plants grown at 18° and 21°. Generally CCC reduced the crop cycle, but not consistently for all cultivar and lighting combinations. Chemical names used: 2-chloro-N,N,N-trimethylethanaminium chloride [chloromequat chloride (CCC)].

Open Access