scholarly journals 545 Controlled Flowering of Oenothera fruticosa L. `Youngii-Lapsley' and Stokesia laevis L'Hér `Klaus Jelitto'

HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 540A-540
Author(s):  
Emily A. Clough ◽  
Arthur C. Cameron ◽  
Royal D. Heins ◽  
William H. Carlson
Keyword(s):  
High Pressure ◽  
Cold Treatment ◽  
Herbaceous Perennials ◽  
Controlled Flowering ◽  
Incandescent Lamps

Oenothera fruticosa L.`Youngii-Lapsley' and Stokesia laevis L'Hér. `Klaus Jelitto' are two hardy herbaceous perennials with great potential as pot crops. The vernalization and photoperiod requirements were examined for each species. Plants were cooled for 0, 3, 6, 9, 12, or 15 weeks at 5 °C with a 9-h photoperiod. After cold treatment, plants were forced in greenhouses at 20 °C under a 16-h photoperiod using high-pressure sodium lamps. The photoperiod requirement was determined by forcing plants at 20 °C with and without a 15-week cold treatment at 5 °C under 10-, 12-, 13-, 14-, 16-, 24-h and 4-h night interruption using incandescent lamps. Plants of Oenothera fruticosa `Youngii-Lapsley' cooled for 0 weeks did not flower. All plants cooled for 3 weeks flowered and time to flower decreased from 53 to 43 days as duration of cold increased from 3 to 15 weeks. `Youngii-Lapsley' flowered under every photoperiod, but time to flower and number of flowers decreased from 54 to 40 days as photoperiod increased from 10 to 24 h. Percentage flowering of Stokesia laevis `Klaus Jelitto' increased from 50 to 100, and time to flower decreased from 112 to 74 days as duration of cold increased from 0 to 6 weeks. Without a cold treatment, plants of `Klaus Jelitto' flowered only under daylengths of 12, 13, and 14 h. After cold treatment, plants flowered under every photoperiod except 24 h, and time to flower decreased from 122 to 65 days as photoperiod increased from 10 to 16 h. Additional aspects of flowering and the effect of different forcing temperatures will be discussed.

scholarly journals Flowering of Herbaceous Perennials under Various Night Interruption and Cyclic Lighting Treatments

HortScience ◽  
1998 ◽  
Vol 33 (4) ◽  
pp. 672-677 ◽  
Author(s):  
Erik S. Runkle ◽  
Royal D. Heins ◽  
Arthur C. Cameron ◽  
William H. Carlson
Keyword(s):  
Plant Height ◽  
Dark Period ◽  
Relative Effectiveness ◽  
Cold Treatment ◽  
Echinacea Purpurea ◽  
Herbaceous Perennials ◽  
Long Day ◽  
Incandescent Lamps ◽  
Lighting Regimen ◽  
Campanula Carpatica

Six long-day species of herbaceous perennials were grown under six night-interruption (NI) photoperiod treatments to determine their relative effectiveness at inducing flowering. Photoperiods were 9-hour natural days with NI provided by incandescent lamps during the middle of the dark period for the following durations: 0.5, 1, 2, or 4 hours; 6 minutes on, 54 minutes off for 4 hours (10% or 6/54 cyclic lighting); or 6 minutes on, 24 minutes off for 4 hours (20% or 6/24 cyclic lighting). For five species, the experiment was repeated with more mature plants; for the sixth, Rudbeckia fulgida Ait. `Goldsturm', following a cold treatment of 8 weeks at 5 °C. The species generally showed a quantitative flowering response to the NI duration until a saturation duration was reached; as the length of the uninterrupted night break increased, flowering percentage, uniformity, and number and plant height increased and time to flower decreased. Minimum saturation durations of NI were 1 hour for Coreopsis grandiflora Hogg ex Sweet `Early Sunrise' and Hibiscus moscheutos L. `Disco Belle Mixed', 2 hours for Campanula carpatica Jacq. `Blue Clips' and Coreopsis verticillata L. `Moonbeam', and 4 hours for unchilled R. fulgida `Goldsturm'. Echinacea purpurea Moench `Bravado' flowered similarly across all lighting treatments. The 6/24 cyclic lighting regimen induced flowering comparable to that under a continual 4-hour NI for four of the six species and the cold-treated R. fulgida `Goldsturm'. Flowering under the 6/54 regimen was generally incomplete, nonuniform, and delayed compared to that under saturation duration treatments. Three of five species flowered earlier when more mature plants were placed under the NI treatments. Cold-treated R. fulgida `Goldsturm' flowered more rapidly than unchilled plants and the saturation duration of NI decreased to 1 hour.

scholarly journals Short Days or Vernalization Promote Flowering in Aquilegia ×hybrida Sims `Origami Blue and White'

HortScience ◽  
2006 ◽  
Vol 41 (4) ◽  
pp. 992A-992 ◽  
Author(s):  
Catherine M. Whitman ◽  
Erik S. Runkle ◽  
Arthur C. Cameron
Keyword(s):  
High Pressure ◽  
Cold Treatment ◽  
Juvenile Stage ◽  
Vernalization Requirement ◽  
Incandescent Lamps ◽  
Short Days

Flowering of Aquilegia is generally considered to require vernalization, while photoperiod has little or no effect. The cold treatment is most effective when plants have passed the juvenile stage (often 12 to 15 leaves) prior to vernalization. We performed experiments on a cultivar reported to have a reduced vernalization requirement. Seedlings of Aquilegia ×hybrida Sims `Origami Blue and White' in 128-cell plug trays with four or five leaves were either placed directly into a 5 °C cooler or transplanted to 13-cm containers. Plants were grown (bulked) for 0, 3, or 6 weeks at 20 °C under 9-h short days (SD) or 16-h long days (LD) provided by incandescent lamps at 1 to 3 μmol·m-2·s-1. Plants had seven or eight leaves after 3 weeks bulking and 13 or 14 leaves after 6 weeks bulking. They were then cooled at 5 °C for 0, 5, or 10 weeks and placed in a common forcing environment of 20 °C under an LD provided by high-pressure sodium lamps. Aquilegia plants placed directly into the forcing environment flowered in 89 and 97 days in years 1 and 2, respectively. Flowering percentage of plants cooled in the plug tray decreased with increasing duration of cold treatment, and only 15% flowered after a 10-week cold treatment. All plants bulked for 3 or 6 weeks prior to cold treatment flowered, and in 26 to 35 days. Surprisingly, all plants that were moved directly from bulking treatments to the forcing environment (no cold treatment) flowered, and flowering was most rapid (36 days) in plants exposed to 6 weeks of SD before forcing. Therefore, our data indicate that SD can at least partially substitute for a cold treatment in this Aquilegia cultivar.

Einfluß der Strömungsform des Gases auf die chemischen Transportprozesse in Halogenglühlampen

1974 ◽  
Vol 29 (10) ◽  
pp. 1471-1477
Author(s):  
Gerhard M. Neumann
Keyword(s):  
High Pressure ◽  
Laminar Flow ◽  
Gas Phase ◽  
Flow Separation ◽  
Gas Flow ◽  
Chemical Transport ◽  
Transport Processes ◽  
Inert Gas ◽  
Good Accord ◽  
Incandescent Lamps

Abstract By raising the inert gas pressure and thus changing the type of gas flow chemical transport processes in tubular halogen incandescent lamps may be influenced. At medium pressures in the region of laminar flow separation of halogen and inert gas due to thermodiffusion occurs, the halogen cycle breaks down, and bulb blackening of the lamp is observed. At low and high pressure, where the streaming behaviour of the gas phase is dominated by diffusion or turbulence, separation of halogen and inert gas is overcome and the lamps stay clean. Observed pressures for changing from laminar to turbulent flow are 3.5 atm in xenon, 5.5 atm in krypton, and > 8 atm in argon in good accord with the well-known Reynolds' criterion.

Cold Treatments Alter the Photoperiodic Flowering Response of Some Herbaceous Perennial Species

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 508c-508
Author(s):  
Erik S. Runkle ◽  
Royal D. Heins ◽  
Arthur C. Cameron ◽  
William H. Carlson
Keyword(s):  
Cold Treatment ◽  
Cold Period ◽  
Photoperiodic Induction ◽  
Perennial Species ◽  
Additional Species ◽  
Flowering Response ◽  
Herbaceous Perennials ◽  
Photoperiodic Flowering ◽  
Herbaceous Perennial ◽  
Short Days

Many species of herbaceous perennials either require a cold treatment for flowering or exhibit enhanced and more desirable flowering characteristics following a cold period. For some species, the photoperiodic induction of flowering can change following cold treatments, the parameters generally becoming less strict as plants receive longer durations of cold until a saturation duration is reached. To quantify the minimum and saturation durations of cold for flowering under short days (SD) and long days (LD), five species were selected and cooled for 0, 3, 6, 9, 12, or 15 weeks at 5 °C, then forced at 20 °C under 9-h photoperiods without (SD) or with a 4-h night interruption (LD). The effects of cold and photoperiod on flowering varied by species. For example, under SD, 0%, 80%, or 100% of Leucanthemum xsuperbum `Snowcap' flowered after 0, 3, or ≥6 weeks at 5 °C, respectively, and time to flower decreased from 103 to 57 days as the duration of cold increased from 3 to 12 weeks. `Snowcap' cooled for ≥3 weeks, then forced under LD, flowered completely in 45 to 55 days. Flowering percentage of Lavandula angustifolia `Hidcote' reached 100 under LD or SD only when plants were cooled for ≥6 or 15 weeks, respectively. Under LD, flowering percentage of Astilbe chinensis pumila progressively increased from 0 to 100 as cold treatment increased from 0 to 15 weeks; flowering percentage under SD was low regardless of cold treatment. Additional species and flowering characteristics will be discussed.

scholarly journals Variation in Floral Induction Requirements of Hibiscus sp.

2001 ◽  
Vol 126 (3) ◽  
pp. 262-268 ◽  
Author(s):  
Ryan M. Warner ◽  
John E. Erwin
Keyword(s):  
High Pressure ◽  
Air Temperature ◽  
Floral Induction ◽  
Ambient Light ◽  
Short Day ◽  
Long Day ◽  
Flower Diameter ◽  
Plant Form ◽  
Incandescent Lamps ◽  
Ornamental Species

Thirty-six Hibiscus L. species were grown for 20 weeks under three lighting treatments at 15, 20, or 25 ± 1.5 °C air temperature to identify flowering requirements for each species. In addition, species were subjectively evaluated to identify those species with potential ornamental significance based on flower characteristics and plant form. Lighting treatments were 9 hour ambient light (St. Paul, Minn., November to May, 45 °N), ambient light plus a night interruption using incandescent lamps (2 μmol·m-2·s-1; 2200 to 0200 hr), or ambient light plus 24-hour supplemental lighting from high-pressure sodium lamps (100 μmol·m-2·s-1). Five day-neutral, six obligate short-day, six facultative short-day, three obligate long-day, and one facultative long-day species were identified. Fifteen species did not flower. Temperature and lighting treatments interacted to affect leaf number below the first flower and/or flower diameter on some species. Hibiscus acetosella Welw. ex Hiern, H. cisplatinus St.-Hil., H. radiatus Cav., and H. trionum L. were selected as potential new commercially significant ornamental species.

scholarly journals Factors Affecting Flowering of Asclepias spp.

HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 467A-467
Author(s):  
G. Nordwig ◽  
J.E. Erwin
Keyword(s):  
High Pressure ◽  
Plant Development ◽  
Continuous Light ◽  
Factors Affecting ◽  
Plant Habit ◽  
Incandescent Lamps ◽  
Potential Use

Asclepias sp. seed were germinated and placed under different photoperiod treatments at constant 15, 20, or 25 ± 2°C. Photoperiod treatments were 8 hr, 8 hr plus night interruption lighting (2200–0200 hr, 2 μmol·m–2·s–1 from incandescent lamps), day extension lighting 1700–2000 HR (100 μmol·m–2·s–1 from highpressure sodium lamps), or daylight plus continuous light (100 μmol·m–2·s–1 light from high-pressure sodium lamps) treatments. Treatments were terminated at anthesis or after 15 weeks. Variation in plant habit and flowering were documented. Also, temperature/photoperiod effects/interactions on plant development are discussed. Lastly, species were classified into appropriate photoperiodic groups and evaluated for potential use as new floriculture crops.

scholarly journals Enhanched Development and Flowering of Rudbeckia hirta in Far-red Amended Environments

HortScience ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 834D-834
Author(s):  
Meriam Karlsson* ◽  
Jeffrey Werner
Keyword(s):  
High Pressure ◽  
Energy Distribution ◽  
Light Quality ◽  
Spectral Energy Distribution ◽  
Spectral Energy ◽  
Flower Buds ◽  
Bedding Plants ◽  
Rudbeckia Hirta ◽  
Flower Diameter ◽  
Incandescent Lamps

The importance of far-red in the spectral energy distribution was evaluated for the development of Rudbeckia hirta. In a high pressure sodium production system of 8 mol·m-2 per day during 16 hours, a limited number of incandescent lamps were added to provide 15 to 20 μmol·m-2 s-1. The red to far-red ratio decreased through the addition of incandescent lighting from |2.2 of high pressure sodium to 1.2. The dwarf R. hirta cultivars Toto Gold, Toto Lemon and Toto Rustic, suitable as container or bedding plants, were transplanted into 10-cm containers 1 month after seeding and the experiment was initiated 3 weeks later. At this time, the plants had 7 to 8 leaves and were 3 to 4 cm in height. Flowering time decreased with 10 to 14 days for the R. hirta cultivars in the incandescent amended environment compared to exclusively high pressure sodium irradiance. Overall plant height averaged 24 cm for `Toto Lemon', 26 cm for `Toto Rustic' and 28 cm for `Toto Gold'. All three cultivars grew |4 cm taller by adding incandescent light. Main branches of each plant averaged 4 with 14 developed flowers and flower buds independent of cultivar and light quality. Average flower diameter increased 0.5 cm in incandescent amended environments to 7.1 cm for `Toto Gold' and `Rustic' and 6.4 cm for `Toto Lemon'.

scholarly journals Photoperiod and Cold Treatment Regulate Flowering of Rudbeckia fulgida `Goldsturm'

HortScience ◽  
1999 ◽  
Vol 34 (1) ◽  
pp. 55-58 ◽  
Author(s):  
Erik S. Runkle ◽  
Royal D. Heins ◽  
Arthur C. Cameron ◽  
William H. Carlson
Keyword(s):  
Plant Height ◽  
Cold Treatment ◽  
Additional Treatment ◽  
Flower Number ◽  
Incandescent Lamps

To determine the flowering requirements of Rudbeckia fulgida Ait. `Goldsturm', plants were grown under 9-hour photoperiods until maturity, then forced at 20 °C under one of seven photoperiods following 0 or 15 weeks of 5 °C. Photoperiods consisted of a 9-hour day that was extended with incandescent lamps to 10, 12, 13, 14, 16, or 24 hours; an additional treatment was a 9-hour day with a 4-hour night interruption (NI). Noncooled `Goldsturm' remained vegetative under photoperiods ≤13 hours, and essentially all plants flowered under photoperiods ≥14 hours or with a 4-hour NI. Flowering percentages for cooled plants were 6, 56, or ≥84 under 10-, 12-, or ≥13-hour daylengths and NI, respectively. Critical photoperiods were ≈14 or 13 hours for noncooled or cooled plants, respectively, and base photoperiods shifted from 13 to 14 hours before cold treatment to 10 to 12 hours following cold treatment. Within cold treatments, plants under photoperiods ≥14 hours or NI reached visible inflorescence and flowered at the same time and developed the same number of inflorescences. Fifteen weeks of cold hastened flowering by 25 to 30 days and reduced nodes developed before the first inflorescence by 28% to 37%. Cold treatment provided little or no improvement in other measured characteristics, such as flowering percentage and uniformity, flower number, plant height, and vigor.

scholarly journals Photoperiod and Temperature Affect Lamium, Scaevola, Verbena, and Calibracoa Development and Propagation

HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 466C-466
Author(s):  
A. Cutlan ◽  
J.E. Erwin ◽  
H. Huntington ◽  
J. Huntington
Keyword(s):  
High Pressure ◽  
Air Temperature ◽  
Plant Development ◽  
Stem Elongation ◽  
Continuous Light ◽  
Flower Induction ◽  
Photoperiodic Flower Induction ◽  
Incandescent Lamps

Lamium maculatum L. `White Nancy', Scaevola aemula R. `New Blue Wonder', Verbena × hybrida Groenl. & Ruempl. `Tapian Blue', and Calibracoa × hybrida `Cherry Pink' were placed under different photoperiod treatments at constant 15, 20, 25, or 30 ± 2°C air temperature. Photoperiod treatments were 9 hr, ambient daylight (≈8 hr) plus night interruption lighting (2200–0200 hr, 2 μmol·m–2·s–1 from incandescent lamps), or ambient daylight plus continuous light (100 μmol·m–2·s–1 light from high-pressure sodium lamps). Data on plant development and rootability of cuttings from each environment was collected. Days to anthesis was lowest when plants were grown under the continuous lighting treatment across species. Verbena and Calibracoa stem elongation was greatest when grown under 30°C under continuous lighting. Species were classified as to photoperiodic flower induction groups. Implications of these data with respect to propagating and finishing these crops are discussed.

scholarly journals Factors Affecting Flowering of Hibiscus spp.

HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 466E-466
Author(s):  
R. Warner ◽  
J.E. Erwin
Keyword(s):  
High Pressure ◽  
Plant Development ◽  
Continuous Light ◽  
Factors Affecting ◽  
Plant Habit ◽  
Incandescent Lamps

Hibiscus spp. seed were germinated and placed under different photoperiod treatments at 15, 20, or 25± 2°C. Photoperiod treatments were 9 hr, ambient daylight (≈9 hr) plus night interruption lighting (2200–0200 hr, 2 μmol·m–2·s–1 from incandescent lamps), or ambient daylight plus continuous light (100 μmol·m–2·s–1 light from high-pressure sodium lamps). Treatments were terminated at anthesis or after 20 weeks. Variation in flowering form and plant habit were documented and will be discussed. Temperature/photoperiod effects/interactions on plant development will be presented. Species were classified into appropriate photoperiodic groups. Those species with potential as new commercial floriculture crops will be presented.

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