Low-level Irradiance during the Dark Period Prevents Photoperiodic-induced Tuberization of Potato

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 542b-542 ◽  
Author(s):  
N.C. Yorio ◽  
G.W. Stutte ◽  
R.M. Wheeler ◽  
L.M. Ruffe
Keyword(s):  
Dark Period ◽  
Light Period ◽  
Photon Flux ◽  
Dark Light ◽  
Fluorescent Lamps ◽  
Light Levels ◽  
Nutrient Film Technique ◽  
Early Maturing ◽  
Metal Halide Lamps ◽  
Inductive Photoperiod

The threshold irradiance during the dark portion of a photoperiod required to inhibit tuberization of potato (Solanum tuberosum L.) was investigated. Two cultivars of potato (cv. Norland, an early maturing variety; cv. Russett Burbank, a late-maturing variety) were grown using nutrient film technique hydroponics in separate tests within a walk-in growth chamber under a normally tuber-inductive photoperiod (12-h light/12-h dark). Light period photosynthetic photon flux (PPF) was provided by either daylight fluorescent lamps (providing 150 μmol·m–2·s–1 PPF) or a combination of daylight fluorescent and metal halide lamps (providing 300 μmol·m–2·s–1 PPF). The chamber was configured with vertically hung shadecloth and a pair of 15-W cool-white fluorescent lamps mounted at one end of the chamber to provide a range of low irradiance during the dark period. The low irradiance treatments averaged 3.65, 0.43, 0.06, and <0.01 μmol·m–2·s–1 PPF for the entire 12-h “dark” period. Results showed that tuberization occurred around 23 DAP, regardless of cultivar or light period PPF for plants grown with 0.06 and <0.01 μmol·m–2·s–1 PPF during the dark period. Tuberization also occurred at around 30 DAP for cv. Norland grown with 0.43 μmol·m–2·s–1 PPF during the dark period. No tubers were formed for either cultivar grown with 3.65 μmol·m–2·s–1 PPF during the dark period. These results indicate that light levels <0.43 μmol·m–2·s–1 PPF do not influence photoperiodic induction of tuberization in potato.

scholarly journals Influence of Daily Light Period and Irradiance on Yield and Leaf Elemental Concentration of Hydroponically Grown Sweetpotato

HortScience ◽  
2009 ◽  
Vol 44 (5) ◽  
pp. 1491-1493 ◽  
Author(s):  
Desmond G. Mortley ◽  
Stephanie Burrell ◽  
Conrad K. Bonsi ◽  
Walter A. Hill ◽  
Carlton E. Morris
Keyword(s):  
Elemental Concentration ◽  
Dilution Effect ◽  
Light Period ◽  
Photon Flux ◽  
Stem Cuttings ◽  
Storage Root ◽  
Root Yield ◽  
Nutrient Film Technique ◽  
Calcium Magnesium ◽  
Lower Irradiance

Growth chamber experiments were conducted to evaluate the effect of irradiance and daily light period on storage root yield and leaf elemental concentration of two sweetpotato cultivars grown hydroponically by use of the nutrient film technique (NFT). Stem cuttings (15 cm) of cv. Whatley/Loretan and Georgia Jet were grown in NFT channels (0.15 × 0.15 × 1.2 m) in reach-in growth chambers under light period/irradiance combinations of 18 h: 300 μmol·m−2·s−1 or 9 h: 600 μmol·m−2·s−1 photosynthetic photon flux. Temperature was 28/22 °C light/dark with a relative humidity of 70% ± 5%. Storage root and foliage yields were greater in both cultivars exposed to a longer daily light period and lower irradiance. The main effect of cultivar indicated that storage root yield was significantly greater among plants of ‘Whatley/Loretan’ compared with that of ‘Georgia Jet’, whereas foliage yield was similar between cultivars. Leaves of plants grown under longer daily light period and lower irradiance had significantly lower concentrations of all elements, nitrogen, phosphorus, potassium, calcium, magnesium, manganese, iron, calcium, boron, and zinc, except for calcium, manganese, and boron. There were no significant differences in leaf elemental concentration between cultivars. Thus, a longer daily light and lower irradiance enhanced biomass production of sweetpotato but reduced leaf elemental concentration probably because of a “dilution” effect.

scholarly journals Enhancement of Growth and Development of Tomato Seedlings by Extending the Light Period Each Day

HortScience ◽  
2005 ◽  
Vol 40 (2) ◽  
pp. 370-373 ◽  
Author(s):  
Hiromi Toida ◽  
Katsumi Ohyama ◽  
Yoshitaka Omura ◽  
Toyoki Kozai
Keyword(s):  
Growth And Development ◽  
Dark Period ◽  
Electric Energy ◽  
Dry Weight ◽  
Light Period ◽  
Photon Flux ◽  
Flower Bud ◽  
Electric Energy Consumption ◽  
Tomato Seedlings ◽  
Bud Initiation

The light and dark periods can be easily controlled by the use of artificial lighting. To understand the effects of alternation of light and dark periods on plant growth and development, we studied the growth and development of tomato (`Momotaro') seedlings under nonperiodic alternation of light and dark periods. Tomato seedlings grown under two nonperiodic alternation treatments of NF (NF-1 and NF-2) were compared with seedlings grown under a periodic alternation treatment (P treatment) with 12-hour light and dark periods. In all treatments, photosynthetic photon flux (PPF) during the light period was maintained at 280 μmol·m-2·s-1; the sum of each light period and the following dark period was 24 hours; and each of the integrated light and dark periods was 132 hours during 11 days of the experiment. In NF-1, the initial light and dark periods were 7 and 17 hours, respectively, and the light period was extended 1 hour per day, while in NF-2, they were initially 17 and 7 hours, respectively, and the light period was shortened 1 hour per day. At the end of the experiment, dry weight per seedling was greater and flower-bud initiation of the first flower truss was earlier in NF-1 than in NF-2 and P, even though the integrated PPF during the experiment was the same in all treatments. These results demonstrate that growth and development of tomato seedlings can be enhanced without any increase in electric energy consumption for lighting by gradually extending the light period or shortening the dark period.

scholarly journals GROWTH OF A LETTUCE CROP IN NASA's BIOMASS PRODUCTION CHAMBER

HortScience ◽  
1991 ◽  
Vol 26 (6) ◽  
pp. 778F-778 ◽  
Author(s):  
R.M. Wheeler ◽  
C.L. Mackowiak ◽  
J.C. Sager ◽  
B. Vieux ◽  
W.M. Knott
Keyword(s):  
Relative Humidity ◽  
Biomass Production ◽  
Lactuca Sativa ◽  
Environmental Conditions ◽  
Life Support ◽  
Support Systems ◽  
Dark Period ◽  
Respiration Rates ◽  
Nutrient Film Technique ◽  
Metal Halide Lamps

Lettuce (Lactuca sativa cv. Waldmann's Green) plants were grown in a large, tightly sealed chamber for NASA's Controlled Ecological Life Support Systems (CELSS) program. Plants were started by direct seeding and grown in 64 0.25-m2 trays (six plants per tray) using nutrient film technique. Environmental conditions included: 23°C, 75% relative humidity, 1000 ubar (ppm) CO2, a 16/8 photoperiod, and 300 umol m-2 s-1 PPF from metal halide lamps. Although the chamber was typically opened once each day for cultural activities, atmospheric ethylene levels (measured with GC/PID) increased from near 15 ppb at 23 days after planting (DAP) to 47 ppb at 28 DAP. At harvest (28 DAP), heads averaged 129 g FW or 6.8 g DW per plant, and roots averaged 0.6 g DW per plant. Some tipburn injury was apparent on most of the plants at harvest. By 28 DAP, stand photosynthesis rates for the entire chamber (approx. 20 m2) reached 17.4 umol CO2 m-2 s-1, while dark-period respiration rates reached 5.5 umol CO2 m-2 s-1. Results suggest that good yields can be obtained from lettuce grown in a tightly sealed environment.

scholarly journals Potential Photosynthetic Advantages of Cucumber (Cucumis sativus L.) Seedlings Grown under Fluorescent Lamps with High Red:far-red Light

HortScience ◽  
2010 ◽  
Vol 45 (4) ◽  
pp. 553-558 ◽  
Author(s):  
Toshio Shibuya ◽  
Ryosuke Endo ◽  
Yuki Kitamura ◽  
Yoshiaki Kitaya ◽  
Nobuaki Hayashi
Keyword(s):  
Cucumis Sativus ◽  
Morphological Changes ◽  
Red Light ◽  
Light Response ◽  
Photosynthetic Photon Flux Density ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Cucumis Sativus L ◽  
Fluorescent Lamps ◽  
Metal Halide Lamps

To evaluate the effect of fluorescent lamps with a high red:far-red (R:FR) light on the potential photosynthesis of transplants, we investigated the photosynthetic light responses of cucumber (Cucumis sativus L.) seedlings grown under fluorescent lamps with high R:FR light (FLH) and compared them with the responses of the seedlings grown under metal-halide lamps (ML) that provided a spectrum similar to that of natural light and under a fluorescent lamp with low R:FR light (FLL). The seedlings were grown under FLH (R:FR = 7.0), ML (R:FR = 1.2), or FLL (R:FR = 1.1) at a photosynthetic photon flux density (PPFD) of 350 μmol·m−2·s−1. The gross photosynthetic rate (Pg), quantum yield of photosystem II (ΦPSII), and photosynthetic electron transfer rate (ETR) of the foliage leaves were then evaluated at PPFDs ranging from 0 to 1000 μmol·m−2·s−1. The photosynthetic light response of FLH seedlings was similar to those of sun leaves, and the responses of ML and FLL seedlings were similar to those of shade leaves. The Pg, ETR, and ΦPSII of FLH seedlings at PPFD of 1000 μmol·m−2·s−1 was 1.38, 1.32, and 1.28 times, respectively, those of ML seedlings, and was 1.40, 1.23, and 1.22 times, respectively, those of FLL seedlings. The Pg was closely correlated with ETR in each treatment. FLH seedlings had thicker leaf and greater chlorophyll content per leaf area than ML and FLL seedlings. The greater Pg of FLH seedlings than in the other two groups of seedlings at high PPFD was probably the result of the improved ETR resulting from physiological and morphological changes in response to the high R:FR light.

Interactions entre le chloramphénicol et la 6-benzylaminopurine au cours du verdissement de cotylédons de concombre

1978 ◽  
Vol 56 (9) ◽  
pp. 1186-1197 ◽  
Author(s):  
N. Farineau ◽  
M. Hoffeltet ◽  
J. Roussaux
Keyword(s):  
Incubation Period ◽  
Dark Period ◽  
Structural Parameters ◽  
Chlorophyll Synthesis ◽  
Light Period ◽  
Biometrical Analysis ◽  
Plastid Differentiation ◽  
Cucumis Sativus L ◽  
Dark Light ◽  
Modes Of Interaction

Etiolated cotyledons of cucumber (Cucumis sativus L.) were incubated for 15 h in the dark followed by 72 h in the light in the presence of 10−6 g/ml 6-benzylaminopurine (6-BAP) or 10−4 g/ml chloramphenicol (CHL). These compounds were applied either permanently or only during the dark period, the first 6 h in the light, or the following 66 h in the light. In all cases 6-BAP stimulates both chlorophyll synthesis and plastid differentiation and increases the area of appressed thylakoids. CHL decreases the rate of chlorophyll synthesis only if given during the whole incubation period (dark + light). However, CHL always inhibits the development of the stroma thylakoids and increases both the number of stacked thylakoids per grana and the size of these thylakoids. During the first 6 h in the light, the structure and pigment content of plastids submitted to 6-BAP and CHL (or conversely) appear to be regulated by the compound applied in the dark period. The changes observed in the following light period (after 6 h) depend on the compound present during this period. These results, and those obtained with the two compounds acting simultanously, indicate that the action of these molecules is localized at different cellular levels. The modes of interaction between 6-BAP and CHL are discussed with reference to a biometrical analysis of some structural parameters of plastids.

scholarly journals Fluorescent Illumination with High Red-to-far-red Ratio Improves Resistance of Cucumber Seedlings to Powdery Mildew

HortScience ◽  
2011 ◽  
Vol 46 (3) ◽  
pp. 429-431 ◽  
Author(s):  
Toshio Shibuya ◽  
Kaori Itagaki ◽  
Motoaki Tojo ◽  
Ryosuke Endo ◽  
Yoshiaki Kitaya
Keyword(s):  
Powdery Mildew ◽  
Morphological Characteristics ◽  
Photon Flux ◽  
Photosynthetic Photon Flux ◽  
Powdery Mildew Fungus ◽  
Fluorescent Lamps ◽  
Foliage Leaf ◽  
Cotyledon Stage ◽  
Epidermal Tissue ◽  
Metal Halide Lamps

We investigated the effects of fluorescent illumination with a high red-to-far-red ratio (R:FR) on the resistance of cucumber (Cucumis sativus) seedlings to powdery mildew fungus (Sphaerotheca cucurbitae; PM). Seedlings were grown at a photosynthetic photon flux (PPF) of 300 μmol·m−2·s−1 provided by fluorescent lamps with high R:FR light (R:FR = 7.0; FLH) or low R:FR light (R:FR = 1.1; FLL) until cotyledons or the first foliage leaf were fully expanded. Spores of PM were then inoculated onto the leaves, and the seedlings were grown for 7 days (from cotyledon stage) or 9 days (from foliage–leaf stage) under FLH. The number of PM colonies on FLH seedlings was 0.80× (cotyledons) and 0.62× (foliage leaves) the number on FLL seedlings. The reduction on the FLH seedlings was probably the result of changes in leaf morphological characteristics such as a thicker epidermal tissue as a result of the higher R:FR illumination. The number of PM colonies on cotyledons of the FLH seedlings was also smaller than that on seedlings grown under metal-halide lamps providing a spectrum similar to that of natural light (R:FR = 1.2).

scholarly journals Growth Responses of Hydroponically Grown Sweetpotato Tolerant and Intolerant of a Continuous Daily Light Period

HortScience ◽  
1996 ◽  
Vol 31 (2) ◽  
pp. 209-212 ◽  
Author(s):  
D.G. Mortley ◽  
P.A. Loretan ◽  
W.A. Hill ◽  
C.K. Bonsi ◽  
C.E. Morris
Keyword(s):  
Ipomoea Batatas ◽  
Production Efficiency ◽  
Elemental Concentration ◽  
Light Period ◽  
Photon Flux ◽  
Storage Root ◽  
Growth Responses ◽  
Area Index ◽  
Nutrient Film Technique ◽  
Half Strength

Two sweetpotato [Ipomoea batatas (L.) Lam] genotypes (`Georgia Jet' and the breeding clone TI-155) were grown at 12-, 15-, 18-, and 21-h light/12-, 9-, 6-, 3-h dark cycles, respectively, to evaluate their growth and elemental concentration responses to duration and amount of daily lighting. Vine cuttings (15 cm long) of both genotypes were grown in rectangular nutrient film technique channels for 120 days. Conditions were as follows: photosynthetic photon flux (PPF) mean 427 μmol·m–2·s–1, 28C day/22C night air cycle, and 70% ± 5% relative humidity. The nutrient solution used was a modified half-strength Hoagland's solution. Storage root count per plant and per unit area, yield (in grams per square meters per day), and harvest index increased, while production efficiency (in grams per mole) decreased with increased daily PPF. Stomatal conductance for both genotypes declined with increased daily PPF. Leaves were smallest for both genotypes at the 21-h light period, while storage root yield declined as leaf area index increased. Except for a linear decrease in leaf N and K with increased light period, elemental concentration was not significantly influenced.

scholarly journals Preference of Sweetpotato Whitefly Adults to Cucumber Seedlings Grown under Two Different Light Sources

2010 ◽  
Vol 20 (5) ◽  
pp. 873-876 ◽  
Author(s):  
Toshio Shibuya ◽  
Junki Komuro ◽  
Norio Hirai ◽  
Yoshiko Sakamoto ◽  
Ryosuke Endo ◽  
...  
Keyword(s):  
Photon Flux ◽  
Light Sources ◽  
Sweetpotato Whitefly ◽  
Dark Cycle ◽  
Cucumber Seedlings ◽  
Fluorescent Lamps ◽  
Morphologic Characteristics ◽  
R:Fr Ratio ◽  
Biotype B ◽  
Metal Halide Lamps

We evaluated the preference of adult sweetpotato whitefly [SPWF (Bemisia tabaci biotype B)] to cucumber (Cucumis sativus) seedlings grown under fluorescent lamps (FLs) or metal-halide lamps (MLs) that provided a spectrum similar to that of natural light. Cucumber seedlings were grown under FLs or MLs at a photosynthetic photon flux of 350 μmol·m−2·s−1 in a 12/12-hour light/dark cycle. The red:far red (R:FR) ratio of FL was 7.0 and that of ML was 1.2. Pairs of cucumber seedlings, one grown under FLs and the other under MLs, were then placed in cages and about 100 SPWF adults were released. There were significantly fewer SPWF adults on the FL cucumber seedlings (36%) than on the ML seedlings (64%) 24 hours after release. FL cucumber seedlings had higher chlorophyll content and thicker leaves than ML seedlings. The lower attractiveness of the FL cucumber seedlings was probably due to changes in morphologic characteristics such as the leaf color and thickness resulting from high R:FR illumination of FL. The fact that light quality affects the plant attractiveness to herbivores should be considered in selecting light sources for transplant production under artificial light.

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.

Immunocytochemical studies on the behavior of RuBisCO and LHCP II during the cell cycle of synchronized Euglena gracilis

1990 ◽  
Vol 48 (3) ◽  
pp. 662-663
Author(s):  
Tetsuaki Osafune ◽  
Shuji Sumida ◽  
Tomoko Ehara ◽  
Eiji Hase ◽  
Jerome A. Schiff
Keyword(s):  
Cell Cycle ◽  
Immunoelectron Microscopy ◽  
Growth Phase ◽  
Euglena Gracilis ◽  
Dark Period ◽  
Light Period ◽  
Carboxylase Activity ◽  
Immunocytochemical Studies ◽  
Lhcp Ii

Changes in the morphology of pyrenoid and the distribution of RuBisCO in the chloroplast of Euglena gracilis were followed by immunoelectron microscopy during the cell cycle in a light (14 h)- dark (10 h) synchronized culture under photoautotrophic conditions. The imrnunoreactive proteins wereconcentrated in the pyrenoid, and less densely distributed in the stroma during the light period (growth phase, Fig. 1-2), but the pyrenoid disappeared during the dark period (division phase), and RuBisCO was dispersed throughout the stroma. Toward the end of the division phase, the pyrenoid began to form in the center of the stroma, and RuBisCO is again concentrated in that pyrenoid region. From a comparison of photosynthetic CO2-fixation with the total carboxylase activity of RuBisCO extracted from Euglena cells in the growth phase, it is suggested that the carboxylase in the pyrenoid functions in CO2-fixation in photosynthesis.

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