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  • Author or Editor: J. W. Kelly x
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Euphorbia pulcherrima `Glory' were grown under natural photoperiods from 5 Oct. to 20 Dec. in specially constructed growth chambers equipped with clear double-walled polycarbonate panels filled with liquids that served as spectral filters. The filters were a blue dye that increased far-red/red FR/R) light, a CuSO4 solution that decreased FR/R, and H2O (control) which did not alter FR/R from natural light. The FR/R values were 1.01, 0.86, and 0.34 for blue dye, H2O (natural), and CuSO4, respectively. FR and R were measured at 725-730 and 655-660nm, respectively.

Plants grown under the CuSO4 filter were 32% shorter, with shorter internodes (48%), greater leaf chlorophyll (25%), and more lateral branches (17%) than controls. Plants grown under blue dye filters did not differ from controls. All plants developed normal bracts and flowers.

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`Spears' (nonpinched and pinched) and `Yellow Mandalay' (pinched) chrysanthemums were grown in growth chambers equipped with clear, double-walled polycarbonate panels filled with liquids that served as spectral filters. A blue dye raised FR/R by filtering out a portion of red light. A solution of CuSO4 lowered FR/R by absorbing a greater portion of far-red than red light. A red dye absorbed much of the blue/green portion of the light spectrum but did not change far-red to red (FR/R) light ratio. Two controls (H2O and air) were used. FR/R values were 1.01 for blue dye, 0.34 for CuSO4, and 0.86 for air, H2O, and red dye. FR and R were measured at 725-730 and 655-660nm, respectively.

All plants grown under CuSO4 filters had reduced height, reduced internode length, and increased chlorophyll content compared to controls. Red dye filtered pinched plants had decreased chlorophyll compared to controls.

Pinched plants grown under CuSO4 filters and long days developed fewer nodes than controls due to the formation of abnormal capitula. The controls and other treatments developed more nodes before producing similar capitula. Stem diameter and leaf area of controls did not differ from blue dye, red dye, or CuSO4 filter treatments.

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Potted Rosa × hybrida `Meijikatar' plants were produced at 350, 700, and 1050 μl·liter-1 CO2. At a stage of development where half of the flowers showed color, plants were placed into simulated shipping incubators for 5 days at 4 or 16 C.

Increased CO2 levels resulted in shorter production time, increased root dry weight, increased plant height, and reduced total chlorophyll in the upper leaves of the plants. Upon removal from simulated shipping, the number of etiolated shoots per plant increased with increased CO2 concentration. After 5 days in a simulated interior environment, higher shipping temperatures induced more leaf chlorosis, but there were no differences in leaf chlorosis due to CO2 enrichment.

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`Spears' chrysanthemums were grown in chambers fitted with double-walled exolite filled with spectral filtering solutions: a blue textile dye that absorbed red light, CuSO4·5H2O that absorbed far-red light, and H2O that was spectrally non-selective (control).

Leaves of `Spears' grown under CuSO4-filters had increased chlorophyll a (23%), chlorophyll b (26%), xanthophyll (22%), and β-carotene (24%) compared to plants grown under H2O or blue-dye filters. Ratios of total carotenoid: chlorophyll and chlorophyll a: chlorophyll b were not affected by filter.

Individual leaf area was reduced 25% under CuSO4 filters compared to other filters. Stomates per unit area were not affected by filters, however stomates per leaf were reduced 25% under CuSO4 filters because of leaf size reduction. Stomate length and width were not affected by filter. Leaves from plants grown under CuSO4-filters had an internal structure resembling that of sun-type leaves. Other filters induced a shade-type leaf.

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The growth of Rosa × hybrida and Exacum affine under different spectral filters was evaluated. Three filters that altered light quality were developed. One, a red textile dye, filtered out much of the blue/green portion of the light spectrum but did not change far-red to red (FR/R) light ratio. Another, a blue textile dye, raised FR/R by filtering out a portion of red light. The third, a salt (copper sulfate) lowered FR/R by filtering out a greater portion of far-red than red light. Two controls were used that did not alter light quality. The filters were installed in specally built growth chambers. Photosynthetic Photon Flux Density (PPFD) was adjusted to equal values in each chamber.

Plants of both species were significantly shorter and had higher leaf chlorophyll, when grown under the low FR/R filter.

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Abstract

Supplemental night lighting of Easter lily (Lilium longiflorum Thunb) plants (2, 5-7) induces early floral initiation and reduces the number of leaves per plant, provided the bulbs (plants) have not been saturated with cold inductive temperatures <21.1°C, the upper limit of vernalization for Lilium ‘Ace’ (6). Also, ‘Ace’ bulbs respond to light during cold storage, which reduces the number of leaves formed before floral initiation and increases the percentage of plants that flower (4). Lighting Allim bulbs during cold storage was also shown by De Mille and Vest (1) to promote early flowering.

Open Access

Abstract

Little research has been conducted on water lilies because of the previous lack of horticultural interest in these species and the difficulty of handling plants in an aquatic environment. Unique anatomical and morphological characteristics associated with these species have been investigated (3), as well as the mechanisms of gas exchange that allow this species to survive underwater (1).

Open Access

Abstract

Ancymidol foliar spray at 66 and 132 mg·liter−1 a.i. significantly decreased height, node number, leaf area, fresh weight, and dry weight of four sunflower cultivars. Ancymidol resulted in darker green leaves and increased chlorophyll content per unit area, as measured spectrophotometrically, when compared with controls. However, chlorophyll a, b, and total chlorophyll were increased in only two cultivars when measured on a weight basis using high-performance liquid chromatography (HPLC). Ancymidol increased three xanthophyll levels (neoxanthin, vio-laxanthin, and lutein) in the four cultivars, but had no effect on β-carotene when measured on a weight basis by HPLC. Chemical name used: a-cyclopropyl-a-(4-methoxyphenyl)-5-pyrimidine methanol (ancymidol).

Open Access

Gerbera seedlings (Gerbera jamesonii H. Bolus Ex. Hook F.) `Florist Strain Yellow' were planted on drip-irrigated, plastic-mulched beds at 24,000, 36,000 or 72,000 plants/ha. Nitrogen and potassium fertilizers at 55, 110, or 220 kg·ha-1 were factorially combined with populations. In the 1st year of a 2-year study, the number of marketable flowers increased as N and K increased to 110 kg·ha-1, but as N and K were increased to 220 kg·ha-1, cull production increased. In the 2nd year, marketable and cull yields increased with N rate to 220 kg·ha-1; K did not affect yield. As populations increased from 24,000 to 72,000 plants/ha, marketable and cull flower production increased in both years. Flower size and quality were unaffected by plant populations. Nitrogen and potassium fertility did not affect flower size, quality, or vase life in either year.

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Description of the light environment used in photomorphogenic research varies greatly among research teams. The environment is often described as the ratio of red (R) to far-red (FR) light, particulary when involvement of the phytochrome system is suspected. There is disagreement in the appropriate center and range of values for each ratio component. Often the center for R is reported as 660 nm. However, in chlorophyll-containing tissue 645 nm may be more appropriate because of the absorption of chlorophyll at 660. Band widths around a selected peak also vary. The widths generally are 10 or 100 nm. Comparison of experiments that describe different peaks or ranges is difficult. Much of the variation in description results from the behavior of phytochrome. Phytochrome has absorption and action spectral peaks, however wavelengths that cause absorption and/or action to a lesser extent may extend more than 50 nm from the peak. Integration formulas such as Pfr/P consider the effects of all wavelengths. However, even the integration formulas do not explain all photomorphogenic responses. A description of the entire photomorphogenic spectrum may be the most appropriate means of communication.

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