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

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.

HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 544D-544 ◽  
Author(s):  
Erik S. Runkle ◽  
Royal D. Heins

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.


2001 ◽  
Vol 126 (3) ◽  
pp. 275-282 ◽  
Author(s):  
Erik S. Runkle ◽  
Royal D. Heins

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.


HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 436E-436
Author(s):  
Teresa A. Cerny ◽  
Nihal C. Rajapakse ◽  
Ryu Oi

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.


HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 681e-681
Author(s):  
Millie S. Williams ◽  
Terri W. Starman ◽  
James E. Faust

The photoperiodic responses were determined for the following species: Bacopa speciosa `Snowflake', Bidens ferulifolium, Brachycome multifida `Crystal Falls', Helichrysum bracteatum'Golden Beauty', Lysimachia procumbens (Golden Globes), Pentas lanceolata `Starburst', Scaevola aemula `New Blue Wonder', Streptocarpella hybrid `Concord Blue', and Streptosolen jamesonii (Orange Browallia). Each plant species was grown at 8-, 10-, 12-, 14-, and 16-hour photoperiods. Photoperiods were provided by delivering 8 hours sunlight, then pulling black cloth and providing daylength extension with incandescent bulbs. Bacopa speciosa `Snowflake', Bidens ferulifolium, Brachycome multifida `Crystal Falls', Helichrysum bracteatum `Golden Beauty', Scaevola aemula `New Blue Wonder', and Streptocarpella hybrid `Blue Concord' were day neutral, i.e., no difference in days to visible bud or days to anthesis in response to photoperiod were observed. Pentas lanceolata `Starburst' and Lysimachia procumbens (Golden Globes) were quantitative long day plants, i.e., days to anthesis decreased as daylength increased. No difference in days to visible bud, number of lateral shoots, number of nodes, or internode length were observed for Pentas lanceolata `Starburst'; however, days to anthesis for 14- and 16-hour photoperiods occurred 9 days earlier than 8-hour photoperiods. Days to visible bud for Lysimachia procumbens (Golden Globes) occurred 7 days earlier and days to anthesis was 9 days earlier under 14- and 16-hour photoperiods than 8-hour photoperiods. By week 8, only one flower per plant developed in the 8-hour photoperiod while 11 flowers per plant developed in the 14-hour photoperiod. Streptosolen jamesonii (Orange Browallia) was a qualitative short day plant. There was no difference in the days to anthesis between 8- and 10-hour daylength, each averaging 36 days from start of photoperiod treatment. Plants under 12- to 16-hour photoperiods did not flower.


HortScience ◽  
2005 ◽  
Vol 40 (1) ◽  
pp. 131-133 ◽  
Author(s):  
Ilias F. Ilias ◽  
Nihal Rajapakse

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.


HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 502C-502
Author(s):  
Millie S. Williams ◽  
Terri W. Starman ◽  
James E. Faust

The photoperiodic responses were determined for the following species: Abutilon hybrid `Apricot', Diascia hybrid `Ruby Fields', Evolvulus glomeratus `Blue Daze', Orthosiphon stamineus `Lavender', Portulaca oleraceae `Apricot', Scaevola aemula `Fancy Fan Falls', Sutera cordata `Mauve Mist' and `Snowflake', Tabernamontana coronaria `Double', and Tibouchina `Spanish Shaw'. Each plant species was grown at 8-, 10-, 12-, 14-, and 16-h photoperiods. Photoperiods were provided by delivering 8 h of sunlight, then pulling black cloth and providing daylength extension with incandescent bulbs. Air temperatures were monitored under each black cloth. Data collected included time to flower, number of flowers, and vegetative characteristics. Diascia, Sutera `Mauve Mist' and `Snowflake', Tabernamontana, and Tibouchina were day neutral with regard to flowering; i.e., no difference in days to visible bud or days to anthesis in response to photoperiod was observed. Portulaca and Scaevola increased in bud and flower number as photoperiod increased from 8 to 16 h, performing similar to quantitative long-day plants. There was no difference in time to flower for Portulaca; however, 70% more flowers were produced under the 16-h photoperiod, compared to the 8-h photoperiod. Scaevola had 26% more flowers under the 16-h than 8-h photoperiod. Abutilon, Evolvulus,and Orthosiphon performed as quantitative short-day plants. Days to visible bud and days to anthesis increased as photoperiod increased for Evolvulus and Orthosiphon, and Abutilon had decreased flower number as photoperiod increased. Although Abutilon had no difference in time to flower, there was a 43% increase in flowers on plants under the 8-h photoperiod vs. 16-h photoperiod. Evolvulus set visible bud and reached anthesis 10 days earlier under 8-h photoperiod than 16-h. Orthosiphon reached visible bud 32 days earlier under an 8-h photoperiod than a 16-h photoperiod.


HortScience ◽  
1993 ◽  
Vol 28 (9) ◽  
pp. 888-890 ◽  
Author(s):  
Peter R. Hicklenton ◽  
Suzie M. Newman ◽  
Lindsay J. Davies

The effects of night temperature (NT) and photosynthetic photon flux (PPF) on time to flower and flower yield in `Bristol Fairy' and `Bridal Veil' Gypsophila paniculata L. (perennial baby's breath) were studied in controlled environments. Plants were grown with nights at 8, 12, 16, and 20C and 450 or 710 μmol·s-1·m-2 photosynthetic photon flux (PPF). Days were at 20C. In both cultivars, the times from the start of treatments to visible bud and from visible bud to anthesis were delayed at the lower PPF and at an NT <20C. The delays in `Bristol Fairy' were greater than those in `Bridal Veil'. Failure of `Bristol Fairy' plants to reach anthesis was common at SC NT and either 450 or 710 μmol·s-1·m-2 PPF; whereas in `Bridal Veil', nearly all plants flowered, regardless of environmental conditions. Flower yield (measured as fresh weight of inflorescences) decreased with NT in `Bristol Fairy' but was highest at 8 or 12C in `Bridal Veil'. In a second experiment using the same cultivars, the effect of curtailing long-day (LD) conditions at various stages on stem elongation and flower yield was investigated. `Bristol Fairy' required more LD cycles (>56) than `Bridal Veil' for maximum stem elongation and flower yield. Terminating LD conditions before the start of inflorescence expansion resulted in lower yields and shorter plants in both cultivars.


Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 637
Author(s):  
Paul Kusuma ◽  
Boston Swan ◽  
Bruce Bugbee

The photon flux in the green wavelength region is relatively enriched in shade and the photon flux in the blue region is selectively filtered. In sole source lighting environments, increasing the fraction of blue typically decreases stem elongation and leaf expansion, and smaller leaves reduce photon capture and yield. Photons in the green region reverse these blue reductions through the photoreceptor cryptochrome in Arabidopsis thaliana, but studies in other species have not consistently shown the benefits of photons in the green region on leaf expansion and growth. Spectral effects can interact with total photon flux. Here, we report the effect of the fraction of photons in the blue (10 to 30%) and green (0 to 50%) regions at photosynthetic photon flux densities of 200 and 500 µmol m−2 s−1 in lettuce, cucumber and tomato. As expected, increasing the fraction of photons in the blue region consistently decreased leaf area and dry mass. By contrast, large changes in the fraction of photons in the green region had minimal effects on leaf area and dry mass in lettuce and cucumber. Photons in the green region were more potent at a lower fraction of photons in the blue region. Photons in the green region increased stem and petiole length in cucumber and tomato, which is a classic shade avoidance response. These results suggest that high-light crop species might respond to the fraction of photons in the green region with either shade tolerance (leaf expansion) or shade avoidance (stem elongation).


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