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  • Author or Editor: M.J. Tsujita x
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Abstract

Flower cutting methods applied to Rosa hybrida L. cv. Samantha grown with supplementary high pressure sodium (HPS) radiant energy must allow for at least one 5-leaflet leaf below the point of cut. Cutting the roses just above the “knuckle”, a point at which the flowering shoot originates, significantly reduced the yield/plant compared to cutting roses at the first 5-leaflet leaf, when grown with supplementary radiant energy but not with ambient light.

Open Access

Abstract

Two cultivars of Rosa hybrida L.—‘Samantha’ and ‘Gabriella’—budded on R. manetti rootstock were grown at root-zone temperatures of 13°C (control-ambient), 18°, and 23° at 13° air night temperature under natural light conditions or natural light plus 55 ± 5 µmol s−1m−2 HPS nightly. Stem length of ‘Samantha’ roses was increased at 23° and the quality index was reduced at 18° soil temperatures. An interaction between light and soil temperature occurred in ‘Gabriella’ roses, where stem length and diameter, fresh weight, quality index, and yield were improved with increased soil zone temperature under natural daylength conditions, but the reverse was the case with HPS supplementary irradiation. Scion cultivar differences on the identical rootstock influenced the response of the plants to root-zone heating and HPS lighting.

Open Access

An experiment was conducted to determine whether the high R:FR ratio in high pressure sodium (HPS) lamps contributes to lateral bud breaking in roses. Rosa hybrida cv. `Samantha' plants were grown under HPS lamps, HPS lamps fitted with blue gel filters to reduce the R:FR ratio or metal halide lamps. Spectral graphs showed R:FR ratios of 1.05, 0.5 and 3.8 for HPS, filtered HPS and metal halide respectively. Although the R:FR ratio in metal halide was notably higher than in HPS the total energy in this range was much lower. At a 24hr supplemental PPF level of 70-75uEm-2s-1 more flowering shoots were produced under HPS and metal halide lighting than under filtered HPS. There were more dormant shoots under the filtered HPS. No differences in quality were found among flowers from any treatment.

Free access

Abstract

Nutrient solutions containing concentrations of 200, 300, 400, and 500 ppm N were applied to Rosa hybrida cv. Caliente grown under either 18 hours of high pressure sodium light of 110µEm-2s-1 quantum flux density or ambient light. Supplemental light increased yield and decreased foliar N and time to flower compared with ambient light. The lowest N level (200 ppm) produced the highest yield under ambient light, but 300 ppm N was optimum under supplemental light High N concentrations reduced stem grade under ambient light. Stem length, stem diameter, fresh weight, keeping quality, days to flower, and foliar nitrogen were not significantly affected by nitrogen treatment.

Open Access
Authors: , , and

Uniconazole was applied as a drench or spray to six hybrid lily (Liliurn sp.) cultivars. Spray application was generally more effective than drench in reducing shoot elongation rate in the first few weeks, and then the efficacy decreased and was less effective than the drench at later stages of plant development. At flowering, a uniconazole drench at 0.1 mg/pot was ineffective for height reduction in `Bravo', `Juliana', and `Sunray' lilies. At higher rates, uniconazole drench was similar to spray in reducing shoot growth in `Bravo' and 306-1 but less effective than spray in `Juliana', `Star Gazer', and `Sunray' lilies. Uniconazole spray reduced plant height at flowering in all the lilies compared to control plants. Days to flower was not affected in `Bravo', `Juliana', and `Sunray' but was increased in `Star Gazer', 306-1, and 306-2 by uniconazole spray treatments. Flowering duration was decreased only in 306-1 by uniconazole spray at 0.2 mg/pot. Chemical name used: (E)-1-(4-chlorophenyl) -4,4 -dimethyl-2-(l,2,4 -triazol-1-yl)-1-penten-3 -ol (uniconazole).

Free access

Abstract

Chrysanthemum morifolium Ramat. cvs. White Marble and Improved Mefo were rooted and grown in cell paks for 34 days under ambient light plus: photoperiodic incandescent night-break lighting 2μE (m−2s−1); 64 μE m−2s−1 high pressure sodium (HPS) dusk to dawn lighting; or 126 μE m−2s−1 HPS dusk to dawn lighting. Container-grown chrysanthemums were fertilized with either 200 ppm N, 86 ppm P and 166 ppm K or 300 ppm N, 129 ppm P and 249 ppm K with every irrigation. After 34 long days these plants were transplanted into raised beds, immediately given short day conditions, and treated as a normal commercial crop. The container-grown treatments were compared to each other and to a bench-grown control which received a total of 48 long days. Supplemental HPS lighting increased the net assimilation rate (NAR), plant dry weight, and height of ‘White Marble’ chrysanthemums after 4 weeks. Increased fertility increased NAR and dry weight in the supplemental light treatment but not in the ambient light treatment. Results were less obvious for “Improved Mefo’. The container-grown treatments were ready for harvest 14 to 22 days before the controls. In both cultivars the high light-high fertility treatment was superior to the other container-grown treatments. The ‘White Marble’ high light-high fertility treatment produced higher quality chrysanthemums than the control, while the same ‘Improved Mefo’ treatment produced chrysanthemums slightly inferior to the control.

Open Access

Sisyrinchium bemudiana L. plants were grown in growth chambers under lo-hour short-day regimes. Scanning electron microscopy of shoot apices collected at biweekly intervals showed that the transition from vegetative to floral status occurs after 10 weeks of short days. Stamens and tepals develop first as common stamentepal primordia that then bifurcate to form outer tepals with stamens opposite. Subsequently, the inner tepals are initiated in an alternate pattern.

Free access

Potted bulbs of Lilium longiflorum Thunb. `Ace' and `Nellie White' and Lilium (Asiatic hybrid) `Enchantment' were grown in a greenhouse under ambient photoperiod (APP), 8-h photoperiod by removing twilight from ambient by blackout cloth (8PP), or 8PP extended with 1 hour of low-intensity far-red radiation (9PP). Height of `Ace', `Nellie White', and `Enchantment' increased by 24%, 18%, and 12%, respectively, under APP and by 118%, 100%, and 44%, respectively, under 9PP compared to 8PP. In a second experiment, the effects of reduced irradiance (0%, 25%, 50%, and 75% shade) were determined on the same cultivars grown under APP or 8PP. The effects of APP on height were similar in magnitude for `Ace' and `Nellie White' but were insignificant for `Enchantment' compared to 8PP. Shading increased height linearly for all cultivars. The regression was greater under APP (2.8 mm/percent shade) than under 8PP (1.8 mm/percent shade) for `Ace' and `Nellie White' combined. Plant height of `Enchantment' was less affected by reduced irradiance. For all cultivars, APP or 9PP produced higher stem dry weight compared to 8PP. Shading decreased leaf and bulb dry weight of the Easter lily cultivars.

Free access

Potted plants of Lilium longiflorum Thunb. cvs. `Ace' and `Nellie White' were grown either under an ambient photoperiod (APP) or under an 8-hour photoperiod (8PP) in a greenhouse. The latter photoperiod was achieved by pulling black cloth over the plants at 1615HR and removing the cloth at 0615HR each day, from emergence to flowering. Within each photoperiod, ambient light intensity was reduced by 0, 20, 40 or 60% using various shade cloths permanently suspended above the plants. Heating was set at 20/16C for the dark/light period, respectively. Plant height, determined from the rim of pot to the top of plant, was 25% lower under 8PP compared to APP for both cultivars. Plant height of `Ace' and `Nellie White' increased by 1.5 mm and 2.5 mm, respectively, per 1% light reduction.

Free access