UTILISATION D’UN MODULE ROTATIF À DEUX NIVEAUX ET DE L’ÉCLAIRAGE ARTIFICIEL POUR LA CULTURE DE L’EXACUM ET DU GÉRANIUM

1990 ◽  
Vol 70 (3) ◽  
pp. 915-923
Author(s):  
MICHEL TARDIF ◽  
BLANCHE DANSEREAU ◽  
ROGER THÉRIAULT
Keyword(s):  
Dry Weight ◽  
Photon Flux ◽  
Ambient Light ◽  
Level System ◽  
Photosynthetic Photon Flux ◽  
The Third ◽  
Width Effect ◽  
Production Practices ◽  
Exacum Affine ◽  
Standard Production

A cultivar of exacum (Exacum affine Balf. f. ’Elfin’) as well as two cultivars of geranium (Pelargonium × hortorum L. H. Bailey ’Hollywood Star’ and ’Hollywood Red’) were given three light treatments. The first treatment using standard production practices received only ambient light, the second treatment using standard production practices received ambient light combined with a photosynthetic photon flux (PPF) of 100 μmol m−2 s−1 provided by high pressure sodium (HPS) lamps, and the third treatment used a rotating two-level system where ambient light on the top level and a PPF of 100 μmol m−2 s−1 on the bottom level were used. An increased growth (height and width) effect was observed for the two geranium cultivars grown on the two-level system compared to the plants receiving the other treatments. The dry weight of exacums grown on the two-level system was 25% greater than those plants receiving only ambient light (during Winter/Spring-88). Certain processes such as thigmomorphogenesis, thermomorphogenesis, and photomorphogenesis may explain physiological modifications undergone by the plants growing on the two-level system.Key words: Rotating two-level system, photosynthetic photon flux, Exacum affine, Pelargonium × hortorum, photomorphogenesis, thermomorphogenesis

High R/FR HPS-pulses enhance earliness of flowering of exacum (Exacum affine Balf. F.) and geranium (Pelargonium × hortorum L. H. Bailey)

1993 ◽  
Vol 73 (4) ◽  
pp. 1163-1167 ◽  
Author(s):  
Michel Tardif ◽  
Blanche Dansereau
Keyword(s):  
High Pressure ◽  
Key Words ◽  
Growth Index ◽  
Dry Weight ◽  
Light Treatment ◽  
Photon Flux ◽  
Ambient Light ◽  
Photosynthetic Photon Flux ◽  
Top Dry Weight ◽  
Exacum Affine

Four consecutive crops (Fall 1988, Winter 1989, Summer 1989 and Fall 1989) of exacum (Exacum affine Balf. f. ’Elfin’) and geranium (Pelargonium × hortorum L. H. Bailey ’Hollywood Star’ and ’Hollywood Red’) were grown in a greenhouse under three lighting treatments: ambient: 16-h high pressure sodium (HPS) lighting of 100 μmol m−2 s−1 between 0600 and 2200 h; and 16 h HPS-pulse lighting (45 s shut off, 90 s recharge) once every hour between 0600 and 2200 h. The growth index [(height × width)/2] of exacum plants was similar, regardless of the light treatment used. However the growth index of both geranium cultivars receiving HPS-pulse lighting was significantly less than those receiving the two other treatments. Exacum top dry weight was 225% greater under pulse lighting than under ambient light. During fall 1988, HPS-pulse lighting increased flower dry weight of Hollywood Red by 400% and 87% compared to ambient and HPS lighting, respectively. Key words: Exacum affine, HPS-pulse, Pelargonium × hortorum, photomorphogenesis, photosynthesis, photosynthetic photon flux

scholarly journals EFFECT OF LIGHT, CO2, AND SUCROSE CONCENTRATIONS ON THE IN VITRO GROWTH OF WHITE POTATO (SOLANUM TUBEROSUM L.)

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 696f-696
Author(s):  
N.C. Yorio ◽  
R.M. Wheeler ◽  
R.C. Weigel
Keyword(s):  
Solanum Tuberosum ◽  
Solanum Tuberosum L ◽  
Dry Weight ◽  
Growth Chamber ◽  
Photon Flux ◽  
Photosynthetic Photon Flux ◽  
White Potato ◽  
High Sucrose ◽  
Effect Of Light

Growth measurements of potato (Solanum tuberosum L.) cvs. Norland (NL), Denali (DN), and Kennebec (KN) were taken from 21-day-old plantlets grown in vitro. Studies were conducted in a growth chamber, with nodal explants grown in culture tubes with loose-fitted Magenta 2-way caps containing Murashige and Skoog salts with either 0, 1, 2 or 3% sucrose. The cultures received either 100 or 300 μmol m-2 s-1 photosynthetic photon flux (PPF), and the growth chamber was maintained at either 400 or 4000 μmol mol-1 CO2. All cvs. showed significant increases in growth on 0% sucrose media at 4000 μmol mol-1 CO2, indicating an autotrophic response. At 400 μmol mol-1 CO2, all cvs. showed an increase in total plantlet dry weight (DW) with increasing sucrose under both PPF levels. Within any sucrose treatment, the highest total DW for all cvs. resulted from 300 μmol m-2 s-1 PPF and 4000 μmol mol-1 CO2. At 4000 μmol mol-1 CO2, shoot DW declined with sucrose above 2% for DN and sucrose above 1% for NL at both PPF levels, suggesting that high sucrose levels may hinder growth when CO2 enrichment is used.

scholarly journals PHOTOAUTOTROPHIC MICROPROPAGATION OF CYMBIDIUM PLB

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 585c-585 ◽  
Author(s):  
Chieri Kubota ◽  
Chalermpol Kirdmanee ◽  
Toyoki Kozai
Keyword(s):  
Chlorophyll Content ◽  
Dry Weight ◽  
Co2 Concentration ◽  
Photon Flux ◽  
Ms Medium ◽  
Photosynthetic Photon Flux ◽  
Photoautotrophic Growth ◽  
Lighting Conditions ◽  
Photoautotrophic Micropropagation

Cymbidium (cv. Lisa rose) PLB (protocorm-like bodies) were cultured in liquid 1/2 MS medium with/without 20 mg g-1 sucrose under continuous lighting conditions. The vessels were shaken at 100 rpm under PPF (photosynthetic photon flux) of 20 and 140 μmol m-2 s-1 and CO2 concentrations outside the vessel (Cout) of 450 and 2000 μmol mol-1 conditions. Photoautotrophic growth was obtained at high PPF and high Cout. The chlorophyll content of the PLB in the medium without sucrose at high PPF and high Cout was almost 3 times that with sucrose at low PPF and low Cout. The number of newly developed PLB with sucrose at low PPF and low Cout was 1.6 times that without sucrose at high PPF and high Cout; the dry weight per unit PLB with sucrose at low PPF and low Cout was almost 3 times that without sucrose at high PPF and high Cout. Photoautotrophic growth of the PLB might be further promoted at higher CO2 concentration (> 1%).

scholarly journals Growth and Interior Performance of Poinsettia in Media Containing Composted Cotton Burrs

HortScience ◽  
1990 ◽  
Vol 25 (4) ◽  
pp. 407-408 ◽  
Author(s):  
Yin-Tung Wang ◽  
Thomas M. Blessington
Keyword(s):  
Electrical Conductance ◽  
Dry Weight ◽  
Pine Bark ◽  
Photon Flux ◽  
Growth Media ◽  
Euphorbia Pulcherrima ◽  
Photosynthetic Photon Flux ◽  
Rooted Cuttings ◽  
Sphagnum Peat ◽  
Number Of Branches

Rooted cuttings of Euphorbia pulcherrima Willd. ex Klotzsch cv. Gutbier V-14 Glory were planted in 2-liter containers with growth media having 0% to 75% composted cotton burrs (CCB) in combination with sphagnum peat and/or composted pine bark. Leachates from media with 50% or more CCB had higher initial electrical conductance (EC) (3.7 to 4.0 dS·m-l) than that from media with 25% or no CCB (2.8 to 3.0 dS·m-l) 2 weeks after planting. The differences in leachate EC declined after an additional 9 weeks. Media containing CCB produced slightly shorter and narrower plants with 10% smaller inflorescences and less dry weight than plants grown in a medium consisting of equal volumes of peatmoss and bark. Number of branches and bracts, days to bloom, and plant grade after 30 days under 15 μmol·s-l· m-2 photosynthetic photon flux were unaffected by media.

scholarly journals Modification of Petunia Seedling Carbohydrate Partitioning by Irradiance

1992 ◽  
Vol 117 (3) ◽  
pp. 477-480
Author(s):  
David F. Graper ◽  
Will Healy
Keyword(s):  
Petunia Hybrida ◽  
Soluble Sugars ◽  
Dry Weight ◽  
Invertase Activity ◽  
Acid Invertase ◽  
Starch Accumulation ◽  
Photon Flux ◽  
Photosynthetic Photon Flux ◽  
Total Carbohydrate ◽  
Relative Growth

Petunia × hybrida Villm. `Red Flash' plants received either 10 or 20 mol·day-1 photosynthetic photon flux (PPF) in growth chambers at: 175 μmol·m-2·s-1 for 16 hours, 350 μmol·m-2·s-1 for 8 or 16 hours, or 350 μmol·m-2 s-1 for 8 hours plus 8 hours of incandescent photoperiod extension (5 μmol·m-2·s-1 PPF). The irradiation components of peak, total, and duration were examined. Doubling total PPF increased total carbohydrate (CHO) production by 60%, seedling dry weight (DW) by 30%, rate of seedling growth by 25%, and acid invertase activity by 50% compared to the other treatments, once the seedlings had reached the two-leaf stage. Seedlings receiving 20 mol·day-1 PPF partitioned 14% more CHO into ethanol soluble sugars rather than starch, which may explain the increase in relative growth rate observed with supplemental irradiance treatments. Extending the photoperiod for 8 hours with 5 μmol·m-2·s-1 PPF reduced total CHO production by 50% compared to the same treatment without photoperiodic lighting. Treatment with 350 μmol·m-2·s-1 for 8 hours resulted in the highest O2 evolution (8.8 μmol O2/min per dm2). Increasing the photoperiod from 8 to 16 hours gave the lowest rate of O2 evolution (4.5 μmol O2/min per dm2). Previous reports of the importance of photosynthetic period in controlling partitioning between starch and sugars may have simply observed a decreasing rate of starch accumulation due to increased total PPF.

scholarly journals Night Interruption Lighting Is Beneficial in the Production of Plugs of Dahlia `Sunny Rose'

HortScience ◽  
2000 ◽  
Vol 35 (7) ◽  
pp. 1244-1246
Author(s):  
Garry Legnani ◽  
William B. Miller
Keyword(s):  
Shoot Growth ◽  
Physiological State ◽  
Dry Weight ◽  
Photon Flux ◽  
Photosynthetic Photon Flux ◽  
Fibrous Root ◽  
Shoot Dry Weight ◽  
Total Plant ◽  
Short Days ◽  
Foliar N Concentration

Experiments were conducted to evaluate effects of photoperiod on growth and dry-weight partitioning in Dahlia sp. `Sunny Rose' during both seedling (plug) production and subsequent production in 10-cm pots. Plugs were grown under short days [9-hour natural photosynthetic photon flux (PPF)] or long days (same 9-hour PPF plus a 4-hour night interruption with incandescent light). Total plant dry weight was unaffected by photoperiod; however, long days (LD) inhibited tuberous root development and increased shoot dry weight, fibrous root dry weight, leaf area, shoot length, and number of leaf pairs. Long days reduced plug production time by ≈1 week compared with short days (SD). Following transplanting to 10-cm pots, shoot growth and foliar development were superior under LD. There was no effect of photoperiod on foliar N concentration. The superior growth of LD plugs following transplanting can be attributed to the plant being in a physiological state conducive to shoot expansion instead of storage.

scholarly journals Blue Light Monochromatic Irradiation for 12 Hours in Lighting Pattern with Combinations of Blue and Red Light Elongates Young Cos Lettuce Leaves and Promotes Growth under High Daily Light Integral

HortScience ◽  
2021 ◽  
pp. 1-6
Author(s):  
Tomohiro Jishi ◽  
Ryo Matsuda ◽  
Kazuhiro Fujiwara
Keyword(s):  
Flux Density ◽  
Blue Light ◽  
Light Emitting Diode ◽  
Red Light ◽  
Dry Weight ◽  
Photosynthetic Photon Flux Density ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Photosynthetic Photon Flux ◽  
Leaf Elongation

Cos lettuce was grown under different spectral photon flux density distribution (SPFD) change patterns with blue- and/or red light-emitting diode (LED) irradiation with a 24-hour cycle. Twelve treatments were designed with a combination of four relative SPFD (RSPFD) change patterns and three photosynthetic photon flux density (PPFD) levels. The RSPFD change patterns were as follows: BR/BR, simultaneous blue- and red-light irradiation (BR) for 24 h; R/BR, red-light monochromatic irradiation (R) for 12 h followed by 12 hours of BR; B/BR, blue-light monochromatic irradiation (B) for 12 hours followed by 12 hours of BR; and B/R, 12 hours of B followed by 12 hours of R. Each RSPFD change pattern was conducted at three daily average photosynthetic photon flux densities (PPFDave) of 50, 100, and 200 µmol·m−2·s−1. The RSPFD change patterns that included B (B/BR and B/R) resulted in elongated leaves. A low ratio of active phytochrome to total phytochrome under B was considered the reason for leaf elongation. Shoot dry weight was significantly greater under the RSPFD change patterns that included B when the PPFDave was 200 µmol·m−2·s−1. The leaf elongation caused by B would have increased the amount of light received and thereby promoted growth. However, excessive leaf elongation caused the plants to fall, and growth was not promoted under the RSPFD change patterns that included B when the PPFDave was 50 µmol·m−2·s−1. Thus, 12-hour B promoted growth under conditions in which leaf elongation leads to increases in the amount of light received.

scholarly journals Application of an Automatic Control System of Photosynthetic Photon Flux Density for LED-Low Light Irradiation Storage of Green Plants

2005 ◽  
Vol 15 (4) ◽  
pp. 781-786 ◽  
Author(s):  
Kazuhiro Fujiwara ◽  
Toshinari Sawada ◽  
Yoshikatsu Kimura ◽  
Kenji Kurata
Keyword(s):  
Flux Density ◽  
Blue Light ◽  
Red Light ◽  
Dry Weight ◽  
Photosynthetic Photon Flux Density ◽  
Light Irradiation ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Photosynthetic Photon Flux ◽  
Low Light

A light-emitting diode (LED)-low light irradiation (LLI) storage system was developed for suppressing the change in dry weight and maintaining the quality of green plants during long-term storage. In this system, the carbon dioxide (CO2) exchange rate was maintained at zero by automatically adjusting the photosynthetic photon flux density (PPFD) with a proportional-integralderivative (PID) controller. The voltage supplied to the LEDs was controlled by the difference between the inflow (400 μmol·mol-1) and outflow CO2 concentrations in the storage case. Grafted tomato (Lycopersicon esculentum; scion = `House Momotaro'; rootstock = `Anchor T') plug seedlings were stored at 10 °C for 35 days under four different LLI conditions as a system operating test: fixed red light irradiation at 2 μmol·m-2·s-1, PID-controlled red light irradiation with no blue light, and PID-controlled red light irradiation with blue light at 0.2 or 1.0 μmol·m-2·s-1. The results showed that the automatic PPFD control during LED-LLI helped suppress changes in dry weight during storage as expected. Furthermore, it was found that addition of a low percentage of blue light improved the morphological appearance of the seedlings and reduced the PPFD required to suppress the change in dry weight.

scholarly journals Year-round Production of Flowering Calathea crocata: Influence of Light and Carbon Dioxide

HortScience ◽  
1993 ◽  
Vol 28 (9) ◽  
pp. 897-898 ◽  
Author(s):  
Johan M. Van Huylenbroeck ◽  
Pierre C. Debergh
Keyword(s):  
Carbon Dioxide ◽  
Day Treatment ◽  
Dry Weight ◽  
Photosynthetic Photon Flux Density ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Leaf Color ◽  
Photosynthetic Photon Flux ◽  
Natural Conditions ◽  
Inductive Treatment

Programmed flower induction of Calathea crocata Morr. et Joris is possible under the controlled environmental conditions of a multilayer growing room. A photoperiod of 10 hours for 9 weeks, growth at 18C, and a photosynthetic photon flux density (PPFD) of 71 μmol·s-l·m-2 induced flowering in more than 95% of the plants and in 50% to 80% of the shoots. In the meantime, none of the plants under natural conditions was induced. Significantly more flowers were induced when PPFD during the short-day treatment was 71 rather than 56 μmol·s-1·m-2. Flowers became visible 14 to 16 weeks after the start of the inductive treatment. Moreover, raising the CO2 concentration to 900 ppm for 5 months increased the leaf area and dry weight by 40%, and resulted in darker leaf color, longer flower stalks, and significantly accelerated flowering (10 days).

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