scholarly journals 569 Photoselective Filters Affect Flowering and Stem Extension In Viola ×wittrockiana and Pisum sativum

HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 544D-544 ◽  
Author(s):  
Erik S. Runkle ◽  
Royal D. Heins
Keyword(s):  
Pisum Sativum ◽  
Light Quality ◽  
Stem Elongation ◽  
Plant Morphology ◽  
Photon Flux ◽  
Spectral Filters ◽  
Density Control ◽  
Long Day ◽  
Long Day Plants ◽  
Peduncle Length

For many plants, light quality has a pronounced effect on plant morphology; light with a low red (R, 600 to 700 nm) to far-red (FR, 700 to 800 nm) ratio promotes stem elongation and a high R: FR, or blue light (B, 400 to 500 nm), suppresses it. In addition, FR light is required for rapid flowering in some species, particularly for long-day plants. Our objective was to quantify how flexible spectral filters, which selectively reduce FR, B, or R, influence plant height and flowering of the quantitative long-day plants Pisum sativum L. `Utrillo' and Viola ×wittrockiana Gams. `Crystal Bowl Yellow'. Plants were grown at 20 °C with reduced FR, B, or R environments or with a neutral density control (C) filter. Calculated phytochrome photoequilebria were 0.78, 0.73, 0.71, or 0.46 for the altered FR, B, C, or R environments, respectively. All filter treatments transmitted a similar photosynthetic photon flux. Sixteen-hour photoperiods were created with natural daylight supplemented with high-pressure sodium lamps positioned above filters. Viola grown under the FR filter never reached 100% flowering within 8 weeks, and visible bud appearance was delayed by at least 17 days compared to all other filters. The R and B filters enhanced peduncle length by at least 25% compared to the C or FR filters. In Pisum, average internode length was 2.2, 2.9, 3.4, and 3.7 cm under the FR, C, B, and R filters, respectively, all statistically different. Fresh and dry shoot weights were similar under the C and FR filters but were at least 35% greater under the B filter and 35% lower under the R filter.

scholarly journals 263 Photoselective Films Influence Flowering of Photoperiodic Species

HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 436E-436
Author(s):  
Teresa A. Cerny ◽  
Nihal C. Rajapakse ◽  
Ryu Oi
Keyword(s):  
Plant Species ◽  
Light Quality ◽  
Red Light ◽  
Photon Flux ◽  
Crop Species ◽  
Plastic Films ◽  
Spectral Filters ◽  
Short Day ◽  
Long Day ◽  
Air Temperatures

Growth chambers constructed from photoselective plastic films were used to investigate the effects of light quality on height manipulation and flowering of photoperiodic plant species. Three types of treatment films were used; control, a far-red light intercepting film (YXE-10) and a red light intercepting film (SXE-4). The red (600-700 nm):far-red (700-800 nm) ratios and phytochrome photoequilibrium estimates for the control, YXE-10 and SXE-4 films were 1.0 and 0.71, 1.5 and 0.77, and 0.71 and 0.67, respectively. The photosynthetic photon flux was adjusted to uniformity among chambers using neutral density filters. Spectral filters did not effect minimum and maximum air temperatures. Experiments were conducted using quantitative long day (Antirrhinum majus and Petunia × hybrida), quantitative short day (Zinnia elegans and Dendranthema × grandiflorum) and day-neutral (Rosa × hydrida) plant species under natural short-day conditions. Plants produced under the YXE-10 filters were significantly shorter than the control plants, while plants produced under the SXE-4 films had similar or increased height compared to the control plants. However, both height response and flowering times varied with the crop species. Flowering time of Rosa × hybrida plants was uniform among all treatments. Flowering of quantitative long-day plants was delayed by at least 10 days under the YXE-10 film and was most responsive to the filtered light. Flowering of quantitative short-day plants was delayed by 2 days under the YXE-10. Days to flower for plants produced under the SXE-4 film were similar to the control plants for all species tested.

scholarly journals Influence of Photoselective Films and Growing Season on Stem Growth and Flowering of Six Plant Species

2003 ◽  
Vol 128 (4) ◽  
pp. 486-491 ◽  
Author(s):  
Teresa A. Cerny ◽  
James E. Faust ◽  
Desmond R. Layne ◽  
Nihal C. Rajapakse
Keyword(s):  
Plant Species ◽  
Light Transmission ◽  
Stem Elongation ◽  
Broad Band ◽  
Flowering Plant ◽  
Photon Flux ◽  
Light Sources ◽  
Long Day ◽  
Control Film ◽  
Long Day Plants

Growth chambers constructed of photoselective plastic films were used to investigate light quality effects on flowering and stem elongation of six flowering plant species under strongly inductive and weakly inductive photoperiods. Three films were used: a clear control film, a far red (FR) light absorbing (AFR) film and a red (R) light absorbing (AR) film. The AFR and AR films intercepted FR (700 to 800 nm) and R (600 to 700 nm) wavelengths with maximum interception at 730 and 690 nm, respectively. The phytochrome photoequilibrium estimates of transmitted light for the control, AFR, and AR films were 0.71, 0.77, and 0.67. The broad band R:FR ratios were 1.05, 1.51, and 0.77, respectively. The photosynthetic photon flux was adjusted with neutral density filters to provide similar light transmission among chambers. Zinnia elegans Jacq., Dendranthema×grandiflorum Kitam. (chrysanthemum), Cosmos bipinnatus Cav., and Petunia×hybrida Vilm.-Andr. plants grown under the AFR film were shorter than control plants. The AFR film had no effect on height of Antirrhinum majus L. (snapdragon) or Rosa×hybrida (miniature rose). Anthesis of zinnia, chrysanthemum, cosmos (short-day plants), and miniature rose (day-neutral plant) was not influenced by the AFR films. Anthesis of petunia and snapdragon (long-day plants) was delayed up to 13 days by AFR films under weakly inductive photoperiods. In petunia, initiation and development of floral structures were not affected by the AFR films during strongly inductive photoperiods. However, during weakly inductive photoperiods, initiation of the floral primordia was significantly delayed and overall development of the floral meristem was slower than control plants indicating that the AFR films could increase the production time if long-day plants were produced off-season. Daylength extension with electric light sources could overcome this delay in anthesis yet achieve the benefit of AFR films for height reduction without the use of chemical growth regulators.

scholarly journals Specific Functions of Red, Far Red, and Blue Light in Flowering and Stem Extension of Long-day Plants

2001 ◽  
Vol 126 (3) ◽  
pp. 275-282 ◽  
Author(s):  
Erik S. Runkle ◽  
Royal D. Heins
Keyword(s):  
Blue Light ◽  
Flower Development ◽  
Red Light ◽  
Wide Band ◽  
Extension Growth ◽  
Photon Flux ◽  
Flower Initiation ◽  
Stem Extension ◽  
Long Day ◽  
Long Day Plants

For many long-day plants (LDP), adding far red light (FR, 700 to 800 nm) to red light (R, 600 to 700 nm) to extend the day or interrupt the night promotes extension growth and flowering. Blue light (B, 400 to 500 nm) independently inhibits extension growth, but its effect on flowering is not well described. Here, we determined how R-, FR-, or B-deficient (Rd, FRd, or Bd, respectively) photoperiods influenced stem extension and flowering in five LDP species: Campanula carpatica Jacq., Coreopsi ×grandiflora Hogg ex Sweet, Lobelia ×speciosa Sweet, Pisum sativum L., and Viola ×wittrockiana Gams. Plants were exposed to Rd, FRd, Bd, or normal (control) 16-hour photoperiods, each of which had a similar photosynthetic (400 to 700 nm) photon flux. Compared with that of the control, the Rd environment promoted extension growth in C. carpatica (by 65%), C. ×grandiflora (by 26%), P. sativum (by 23%), and V. ×wittrockiana (by 31%). The FRd environment suppressed extension growth in C. ×grandiflora (by 21%), P. sativum (by 17%), and V. ×wittrockiana (by 14%). Independent of the R: FR ratio, the Bd environment promoted stem extension (by 10% to 100%) in all species, but there was little or no effect on flowering percentage and time to flower. Extension growth was generally linearly related to the incident wide band (100 nm) R: FR ratio or estimated phytochrome photoequilibrium except when B light was specifically reduced. A high R: FR ratio (i.e., under the FRd filter) delayed flower initiation (but not development) in C. carpatica and C.×grandiflora and inhibited flower development (but not initiation) in V.×wittrockiana. Therefore, B light and the R: FR ratio independently regulate extension growth by varying magnitudes in LDP, and in some species, an FRd environment can suppress flower initiation or development.

scholarly journals Effects of HPS and LED lighting on cucumber leaf photosynthesis, light quality penetration and temperature in the canopy, plant morphology and yield

2017 ◽  
Vol 26 (2) ◽  
Author(s):  
Liisa Elina Särkkä ◽  
Kari Jokinen ◽  
Carl-Otto Ottosen ◽  
Timo Kaukoranta
Keyword(s):  
Light Quality ◽  
Stem Elongation ◽  
Plant Morphology ◽  
Light Level ◽  
Yield Potential ◽  
Flower Initiation ◽  
Initiation Rate ◽  
Led Lighting ◽  
Use Efficiency ◽  
Lower Temperature

In Nordic countries during the winter months supplemental lighting is essential for year-round cucumber production. In this research the effects of full HPS (top and interlights) illumination is compared to hybrid (HPS top, LED interlights) and full LED (top and interlights). The results showed that fruit yield was highest in the HPS-LED treatment whereas the electrical use efficiency (kg yield J-1) increased when HPS was replaced with LED. In LED-LED the light use efficiency (g fruit FW mol-1 PAR) was highest but resulted in a fewer number of fruits in mid-winter particularly and the lowest yield potential. The lower temperature and lower light level due to LED-LED lighting lead to reduced photosynthesis capacity, flower initiation rate and water use efficiency whereas increased stem elongation and leaf expansion compared to other treatments. Differences in light quality of LED and HPS are also discussed in terms of cucumber yield formation.

scholarly journals Regulation of Chrysanthemum Growth by Spectral Filters

1992 ◽  
Vol 117 (3) ◽  
pp. 481-485 ◽  
Author(s):  
Nihal C. Rajapakse ◽  
John W. Kelly
Keyword(s):  
Light Quality ◽  
Leaf Size ◽  
Experimental Period ◽  
Internode Length ◽  
Photon Flux ◽  
Average Height ◽  
Dry Matter Accumulation ◽  
Water Control ◽  
Spectral Filters

The role of light quality and quantity in regulating growth of vegetative Dendranthema × grandiflorum (Ramat.) Kitamura was evaluated using CuSO4 solutions and water (control) as spectral filters. Copper sulfate filters increased the red (R): far-red (FR) and the blue (B): R ratios (R = 600 to 700 nm; FR = 700 to 800 nm; B = 400 to 500 urn) of transmitted light. Photosynthetic photon flux (PPF) under 4%, 8% and 16% CuSO4 filters was reduced 26%, 36%, and 47%, respectively, from natural irradiance in the greenhouse, which averaged ≈ 950 μmol·m-2·s-1. Control treatments were shaded with Saran plastic film to ensure equal PPF as the corresponding C uSO4 chamber. Average daily maxima and minima were 26 ± 3C and 16 ± 2C. At the end of the 4-week experimental period, average height and internode length of plants grown under CuSO4 filters were ≈ 40% and 34% shorter than those of plants grown under control filter. Reduction in plant height and internode length was apparent within 1 week after the beginning of treatment. Total leaf area (LA) was reduced by 32% and leaf size (LS) was reduced by 24% under CuSO4 filters. Specific leaf weight (SLW) was higher under CuSO4 filters than for the controls. Irradiance transmitted through CuSO4 filters reduced fresh and dry leaf weights by 30%. Fresh and dry stem weights of plants grown under CuSO4 filters were 60% lower than those of controls. Relative dry matter accumulation into leaves was increased in plants grown under CuSO4 filters while it was reduced in stems. A single application of GA3 before irradiation partially overcame the height reduction under CuSO4 filters, suggesting GA biosynthesis/action may be affected by light quality. Our results imply that alteration of light quality could be used to control chrysanthemum growth as an alternative method to conventional control by chemical growth regulators. Chemical names used: gibberellic acid (GA)

scholarly journals The Effects of End-of-the-day Red and Far-red Light on Growth and Flowering of Petunia ×hybrida `Countdown Burgundy' Grown under Photoselective Films

HortScience ◽  
2005 ◽  
Vol 40 (1) ◽  
pp. 131-133 ◽  
Author(s):  
Ilias F. Ilias ◽  
Nihal Rajapakse
Keyword(s):  
Adverse Effects ◽  
Petunia Hybrida ◽  
Stem Elongation ◽  
Red Light ◽  
Main Stem ◽  
Percentage Increase ◽  
Minute Exposure ◽  
Long Day ◽  
Long Day Plants ◽  
Delayed Flowering

The objective of this research was to investigate if brief exposure to end-of-the-day (EOD) red (R) or far red (FR) light can overcome the flowering delay of petunia (Petunia ×hybrida Vilm.-Andr. `Countdown Burgundy') grown under FR deficient greenhouse environments with no adverse effects on stem elongation. Plants were grown under clear, FR, and R light absorbing greenhouse films (control, AFR, and AR films, respectively) and exposed to R or FR light at the end of the photoperiod for 15 minutes. At flowering, main stem of plants grown under the AR film was about 17% longer and that of AFR film grown plants (without EOD treatment) was about 50% shorter than control plants. EOD-R light reduced stem elongation of control plants but had no effect on AFR or AR film-grown plants. EOD-FR light increased stem elongation in plants grown under AR and AFR films but the percentage increase was greater under AFR film (7%, 19%, and 64% increase in control, AR, and AFR films, respectively). However, plants that received EOD-FR light under AFR film were 25% shorter than control plants that received no EOD light. AFR film delayed flowering by 11 days but AR film had no effect. Fifteen-minute exposure to EOD-R or -FR light had no effect on flowering under control and AFR film. Although the exposure to brief EOD-FR partially increased stem elongation, it was not sufficient to accelerate flowering. Treatments to enhance flowering can cause stem elongation. Therefore, care should be taken to avoid improper crop timing, especially with long-day plants.

scholarly journals Influence of Spectral Filters on Height, Leaf Chlorophyll, and Flowering of Rosa × hybrida ‘Meirutral’

1990 ◽  
Vol 8 (4) ◽  
pp. 209-211
Author(s):  
M.J. McMahon ◽  
J.W. Kelly
Keyword(s):  
Light Quality ◽  
Red Light ◽  
Rosa Hybrida ◽  
Photon Flux ◽  
Textile Dye ◽  
Photosynthetic Photon Flux ◽  
Flower Buds ◽  
Spectral Filters ◽  
Leaf Chlorophyll ◽  
Growth Chambers

Abstract Growth of Rosa × hybrida ‘Meirutral’ under different spectral filters was evaluated. Two filters that altered far-red (730 nm)/red (660 nm) light (FR/R) were developed. One, a blue textile dye, increased FR/R by filtering out a portion of red light. The second, a salt (copper sulfate) decreased FR/R by filtering out a greater portion of far-red than red light. A third filter that did not alter light quality was the control. The filters were installed in specially built growth chambers. Photosynthetic photon flux (PPF) was adjusted to equal values in each chamber. Plants were significantly shorter and had higher leaf chlorophyll when grown under the reduced FR/R filter. The number of flower buds and number of buds showing color at termination of the experiment was not affected by light quality treatments.

scholarly journals Spectral Filters Influence Transpirational Water Loss in Chrysanthemum

HortScience ◽  
1993 ◽  
Vol 28 (10) ◽  
pp. 999-1001 ◽  
Author(s):  
Nihal C. Rajapakse ◽  
John W. Kelly
Keyword(s):  
Leaf Area ◽  
Water Use ◽  
Water Loss ◽  
Light Quality ◽  
Stomatal Density ◽  
Photosynthetic Photon Flux Density ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Water Control ◽  
Spectral Filters

Transpiration rates of chrysanthemum [Dendranthema ×grandiflorum (Ramat.) Kitamura] plants grown under spectral filters were evaluated as part of an investigation on using light quality to regulate plant growth. The 6% CuSO4·5H2O spectral filter reduced photosynthetic photon flux density in red (R) and far red (FR) wavelengths and increased the R: FR and blue (B): R ratios (B = 400 to 500 nm; R = 600 to 700 nm; FR = 700 to 800 nm) of transmitted light relative to the water (control) filter. After 28 days, cumulative water use of plants grown under CuSO4 filters was ≈37% less than that of control plants. Transpiration rates were similar among plants grown under CuSO4 and control filters when expressed as leaf area, a result suggesting that the reduced cumulative water loss was a result of smaller plant size. Plants grown under CuSO4 filters had slightly lower (10%) stomatal density than control plants. Light transmitted through CuSO4 filters did not alter the size of individual stomata; however, total number of stomata and total stomatal pore area per plant was ≈50% less in plants grown under CuSO4 filters than in those grown under control filters due to less leaf area. The results suggest that altering light quality may help reduce water use and fertilizer demands while controlling growth during greenhouse production.

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