scholarly journals Supplemental Light Quality Affects Budbreak, Yield, and Vase Life of Cut Roses

HortScience ◽  
1993 ◽  
Vol 28 (6) ◽  
pp. 621-622 ◽  
Author(s):  
G.L. Roberts ◽  
M.J. Tsujita ◽  
B. Dansereau
Keyword(s):  
High Pressure ◽  
Total Energy ◽  
Quality Index ◽  
Light Quality ◽  
Metal Halide ◽  
Photon Flux ◽  
Vase Life ◽  
Photosynthetic Photon Flux ◽  
R:Fr Ratio ◽  
Metal Halide Lamps

Rosa ×hybrida `Samantha' plants were grown under high-pressure sodium (HPS) lamps, HPS lamps fitted with blue gel filters to reduce the red to far-red (R:FR) ratio, or metal halide lamps. R: FR ratios were 1:0.95, 1:2, and 1:0.26 for HPS; filtered HPS, and metal halide, respectively. Although the R: FR ratio for metal halide was 3.5 times higher than for HPS, the total energy from 630 to 750 nm was 2.8 times lower. At a nighttime supplemental photosynthetic photon flux of 70 to 75 μmol·m-2.s-1, plants under HPS and metal halide lamps produced 49 % and 64% more flowering shoots, respectively, than those under filtered HPS (averaged over two crop cycles). The quality index for flowers under HPS, metal halide, and filtered HPS was 25.0, 23.3, and 18.5, respectively. Vase life was 10 to 11 days, regardless of treatment.

scholarly journals RED TO FAR-RED RATIO IN HIGH-PRESSURE SODIUM LIGHTS AFFECTS YIELD IN ROSES

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 648f-648
Author(s):  
Glenn L. Roberts ◽  
M. J. Tsujita
Keyword(s):  
High Pressure ◽  
Total Energy ◽  
Metal Halide ◽  
Lateral Bud ◽  
R:Fr Ratio ◽  
Bud Breaking ◽  
Metal Halide Lamps

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.

scholarly journals Vegetative Growth of Potato under High-pressure Sodium, High-pressure Sodium SON-Agro, and Metal Halide Lamps

HortScience ◽  
1995 ◽  
Vol 30 (2) ◽  
pp. 374-376 ◽  
Author(s):  
N.C. Yorio ◽  
C.L. Mackowiak ◽  
R.M. Wheeler ◽  
J.C. Sager
Keyword(s):  
High Pressure ◽  
Vegetative Growth ◽  
Dry Weight ◽  
Metal Halide ◽  
Photon Flux ◽  
Spectral Quality ◽  
Photosynthetic Photon Flux ◽  
Total Dry Weight ◽  
Metal Halide Lamps

Potato (Solanum tuberosum L. cvs. Norland and Denali) plants were grown under high-pressure sodium (HPS), metal halide (MH), and blue-light-enhanced SON-Agro high-pressure sodium (HPS-S) lamps to study the effects of lamp spectral quality on vegetative growth. All plants were initiated from in vitro nodal cultures and grown hydroponically for 35 days at 300 μmol·m–2·s–1 photosynthetic photon flux (PPF) with a 12-hour light/12-hour dark photoperiod and matching 20C/16C thermoperiod. `Denali' main stems and internodes were significantly longer under HPS compared to MH, while under HPS-S, lengths were intermediate relative to those under other lamp types, but not significantly different. `Norland' plants showed no significant differences in stem and internode length among lamp types. Total dry weight of `Denali' plants was unaffected by lamp type, but `Norland' plants grown with HPS had significantly higher dry weight than those under either HPS-S or MH. Spectroradiometer measurements from the various lamps verified the manufacturer's claims of a 30% increase in ultraviolet-blue (350 to 450 nm) output from the HPS-S relative to standard HPS lamps. However, the data from `Denali' suggest that at 300 μmol·m–2·s–1 total PPF, the increased blue from HPS-S lamps is still insufficient to consistently maintain short stem growth typical of blue-rich irradiance environments.

scholarly journals Day-long Alterations of the Photomorphogenic Light Environment Affect Young Watermelon Plant Growth: Implications for Use with Rowcovers

1997 ◽  
Vol 7 (3) ◽  
pp. 261-264 ◽  
Author(s):  
Dennis R. Decoteau ◽  
Heather A. Hatt Graham
Keyword(s):  
Plant Growth ◽  
Blue Light ◽  
Light Quality ◽  
Citrullus Lanatus ◽  
Red Light ◽  
Broad Band ◽  
Metal Halide ◽  
Photon Flux ◽  
Photosynthetic Photon Flux ◽  
Metal Halide Lamps

The sensitivity of watermelon [Citrullus lanatus (Thumb.) Matsum & Naki `Sugar Baby'] plant growth to day-long alterations in light quality was determined by exposing plants to light transmitted through broad band wavelength selective filters. Of the three acetate filters analyzed (nos. 19, 27, and 74), filter no. 74 transmitted the least amount of photosynthetic photon flux (PPF) (400 to 700 nm), the smallest red light: far-red light ratio (R:FR) (645:735 nm), and the greatest amount of blue light (400 to 500 nm) radiation from metal halide lamps. Plants grown under filter no. 74 were taller, had elongated petioles, and had a greater amount of petiole and stem biomass than plants grown under the other filters. Spectral transmission properties of commercially available rowcover materials were evaluated for variation of PPF, R:FR, and blue light. Clear polyethylene rowcovers were completely permeable to all measured (330 to 850 nm) wavelengths of radiation from metal halide lamps. White polyethylene rowcovers were the least permeable of the rowcover materials to wavelengths of radiation with decreases in the PPF, R:FR, and blue light. Spunbonded polyester materials slightly reduced PPF, R:FR, and blue light. Plants grown under white polyethylene and spunbonded materials grew taller (longer stems) than plants grown under the clear polyethylene rowcover. Petiole lengths were generally longer for plants grown under white polyethylene. Our results suggests that alterations in the R:FR and blue light due to selected wavelength transmission through commercially available rowcover material alter early watermelon growth.

SUPPLEMENTARY LIGHTING FOR RESEARCH GREENHOUSES

1984 ◽  
Vol 64 (3) ◽  
pp. 773-779 ◽  
Author(s):  
E. ANN CLARK ◽  
M. D. DEVINE
Keyword(s):  
High Pressure ◽  
Plant Growth ◽  
Flux Density ◽  
Growth And Development ◽  
Photosynthetic Photon Flux Density ◽  
Metal Halide ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Photosynthetic Photon Flux ◽  
Supplementary Lighting

The growth and development of six plant species were measured under a standardized photosynthetic photon flux density (PPFD) supplied by fluorescent, metal halide, or high-pressure sodium lamps. Overall, plant growth and seed yield were in the order of high-pressure sodium > metal halide > fluorescent. Although the units tested were unable to supply a uniform, high flux density, acceptable plant growth was achieved under the compromise arrangements used.Key words: Fluorescent, metal halide, high pressure sodium, supplementary lighting

scholarly journals SPECTRAL CHANGES IN METAL HALIDE AND HIGH PRESSURE SODIUM LAMPS EQUIPPED WITH ELECTRONIC DIMMING

HortScience ◽  
1991 ◽  
Vol 26 (6) ◽  
pp. 738A-738 ◽  
Author(s):  
David L. Bubenheim ◽  
Raman Sargis ◽  
David Wilson
Keyword(s):  
High Pressure ◽  
High Speed ◽  
Input Power ◽  
Metal Halide ◽  
Photon Flux ◽  
Photosynthetic Photon Flux ◽  
Spectral Changes ◽  
Spectral Peaks ◽  
Equilibrium Ratio ◽  
Full Power

Electronic dimming of high intensity discharge lamps offers control of photosynthetic photon flux (PPF) but is often characterized as causing significant spectral changes. Growth chambers with 400 W metal halide (MH) and high pressure sodium (HPS) lamps were equipped with a dimmer system using silicon controlled rectifiers (SCR) as high speed switches. Phase control operation turned the line power off for some period of the AC cycle. At full power the electrical input to HPS and MH lamps was 480 W (RMS) and could be decreased to 267 W and 428 W, respectively, before the arc was extinguished. Concomitant with this decrease in input power, PPF decreased by 60% in HPS and 50% in MH. The HPS lamp has characteristic spectral peaks at 589 and 595 nm. As power to the HPS lamps was decreased the 589 nm peak remained constant while the 595 nm peak decreased, equalling the 589 nm peak at 345 W input, and was almost absent at 270 W input. The MH lamp has a broader spectral output but also has a peak at 589 nm and another, smaller peak, at 545 nm. As input power to the MH lamps decreased the 589 nm peak diminished to equal the 545 nm peak. As input power approached 428 W the 589 nm peak shifted to 570 nm. While a spectral change was observed as input power was decreased in both MH and HPS lamps, the phytochrome equilibrium ratio (Pfr/Ptot) remain unchanged for both lamp types.

scholarly journals Lamp Type and Irradiance Level for Daylength Extensions Influence Flowering of Campanula carpatica `Blue Clips', Coreopsis grandiflora `Early Sunrise', and Coreopsis verticillata `Moonbeam'

1998 ◽  
Vol 123 (5) ◽  
pp. 802-807 ◽  
Author(s):  
Catherine M. Whitman ◽  
Royal D. Heins ◽  
Arthur C. Cameron ◽  
William H. Carlson
Keyword(s):  
High Pressure ◽  
Photon Flux ◽  
Photosynthetic Photon Flux ◽  
Irradiance Level ◽  
Species Saturation ◽  
Fluorescent Lamps ◽  
Saturation Irradiance ◽  
Incandescent Lamps ◽  
Metal Halide Lamps ◽  
Campanula Carpatica

The effectiveness of cool-white fluorescent, high-pressure sodium, incandescent, and metal halide lamps for inducing flowering through daylength extensions in Campanula carpatica Jacq. `Blue Clips', Coreopsis grandiflora Hogg ex Sweet `Early Sunrise', and Coreopsis verticillata L. `Moonbeam' was compared. Lighting was delivered as a 7-hour day extension with photosynthetic photon flux (PPF) ranging from 0.05 to 2.0 μmol·m-2·s-1 following a 9-hour natural daylength. Threshold irradiance values for flowering ranged from <0.05 to 0.4 μmol·m-2·s-1, depending on species. Saturation irradiance values for Campanula carpatica `Blue Clips' and C. grandiflora `Early Sunrise' were between 0.2 ± 0.2 and 0.7 ± 0.5 μmol·m-2·s-1, and did not differ between lamps. An irradiance of 1.0 μmol·m-2·s-1 from any lamp was adequate for flowering in Coreopsis verticillata `Moonbeam'. Time to flower at irradiances above the saturation points did not differ significantly between lamp types for all species tested. Campanula carpatica `Blue Clips' and Coreopsis grandiflora `Early Sunrise' plants had significantly longer stems under incandescent lamps than in any other treatment. Coreopsis verticillata `Moonbeam' plants grown under cool-white fluorescent lamps had stems ≈10% longer than those grown under high-pressure sodium or incandescent lamps.

scholarly journals Response of Oxypetalum caeruleum to Irradiance, Temperature, and Photoperiod

1990 ◽  
Vol 115 (6) ◽  
pp. 910-914 ◽  
Author(s):  
A.M. Armitage ◽  
N.G. Seager ◽  
I.J. Warrington ◽  
D.H. Greer ◽  
J. Reyngoud
Keyword(s):  
Stem Elongation ◽  
Net Photosynthesis ◽  
Stem Length ◽  
Photon Flux ◽  
Vase Life ◽  
Photosynthetic Photon Flux ◽  
Node Number ◽  
Stem Strength ◽  
Flower Abortion ◽  
Reduced Time

Incremental increases in temperature from 14 to 22 to 30C resulted in linear increases in stem length and node number and decreases in stem diameter and stem strength of Oxypetalum caeruleum (D. Don.) Decne. Higher temperatures also resulted in additional flower abortion, reduced time to flowering, and fewer flowering stems per inflorescence. Reduction in the photosynthetic photon flux (PPF) from 695 to 315 μmol·s-1·m-2 had similar effects as increasing the temperature on vegetative characteristics, but had little effect on reproductive ones. The rate of stem elongation was greatest at low PPF for all temperatures and at high temperature for all PPF treatments. Net photosynthesis rose between 14 and 22C and declined at 30C for all PPF treatments. Long photoperiods (12 or 14 hours) resulted in longer internodes, longer stems, and more flowers per cyme than short photoperiods (8 or 10 hours), but photoperiod had little effect on flowering time. Treatments to reduce latex coagulant and silver thiosulfate treatments had no significant effect on vase life.

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