scholarly journals Floral Development and Bolting of Spinach as Affected by Photoperiod and Integrated Photosynthetic Photon Flux During Transplant Production

HortScience ◽  
2001 ◽  
Vol 36 (5) ◽  
pp. 889-892 ◽  
Author(s):  
Changhoo Chun ◽  
Machiko Tominaga ◽  
Toyoki Kozai
Keyword(s):  
Air Temperature ◽  
Vegetative Growth ◽  
Floral Development ◽  
Spinacia Oleracea ◽  
Short Photoperiod ◽  
Photon Flux ◽  
Photosynthetic Photon Flux ◽  
Flower Stalk ◽  
Stalk Length

We recently showed that spinach (Spinacia oleracea L.) transplants produced under a short photoperiod and low air temperature were characterized by a delay of bolting and short flower-stalk length at harvest (Chun et al., 2000a). The present study was conducted to determine whether these changes are caused by the short photoperiod itself or by the lower integrated photosynthetic photon flux (IPPF). Shoot and root dry weights of transplants increased significantly with increasing IPPF, but were not affected by a change in the photoperiod. However, the floral development indices of transplants were significantly greater under a 16-than under a 10- or 13-hours/day photoperiod, but were not affected by a change in IPPF. The percentage of bolted plants 3 days after transplanting (DAT) increased significantly with increasing photoperiod (from 0% at 10 hours/day to more than 85% at 16 hours/day). Flower-stalk length increased with increasing photoperiod (e.g., at 14 DAT, from 15 mm at the shorter photoperiods to 80 mm at 16 hours/day), but was not affected by a change in IPPF. These results show that the delay of bolting that occurs when the photoperiod is reduced during transplant production is due to the delay of floral development and not to retarded vegetative growth as a result of reduced IPPF.

scholarly journals Bolting and Growth of Spinacia oleracea L. Can be Altered by Modifying the Photoperiod during Transplant Production

HortScience ◽  
2000 ◽  
Vol 35 (4) ◽  
pp. 624-626 ◽  
Author(s):  
Changhoo Chun ◽  
Ayumi Watanabe ◽  
Toyoki Kozai ◽  
Hyeon-Hye Kim ◽  
Junya Fuse
Keyword(s):  
High Temperature ◽  
Spinacia Oleracea ◽  
Market Value ◽  
Photon Flux ◽  
Artificial Light ◽  
Photosynthetic Photon Flux ◽  
Flower Stalk ◽  
Spinacia Oleracea L ◽  
Critical Photoperiod ◽  
Long Photoperiod

Spinach (Spinacia oleracea L. cv. Dimple) was chosen to determine whether bolting (i.e., elongation of flower stalks) could be controlled by manipulating the photoperiod during transplant production in a closed system using artificial light. Plants grown under various photoperiods during transplant production were transferred and cultured under natural short photoperiods and artificial long photoperiods. Vegetative growth at transplanting tended to be greater with the longer photoperiod because of the increased integrated photosynthetic photon flux. Bolting initiation reacted qualitatively to a long photoperiod, and the critical photoperiod for bolting initiation was longer than 13 h and shorter than 15 h. The plants grown under a longer photoperiod during transplant production had longer flower stalks at harvest. The long photoperiod and/or high temperature after transplanting therefore promoted flower stalk elongation. Growing plants under a photoperiod that was shorter than the critical photoperiod during transplant production reduced elongation of the flower stalks, thus there was no loss of market value even though the plants were cultured under a long photoperiod and high temperature for 2 weeks after transplanting.

scholarly journals Effects of Air Temperature Regimes on Physiological Disorders and Floral Development of Tomato Seedlings Grown under Continuous Light

HortScience ◽  
2005 ◽  
Vol 40 (5) ◽  
pp. 1304-1306 ◽  
Author(s):  
Katsumi Ohyama ◽  
Yoshitaka Omura ◽  
Toyoki Kozai
Keyword(s):  
Air Temperature ◽  
Floral Development ◽  
Continuous Light ◽  
Photon Flux ◽  
Photosynthetic Photon Flux ◽  
Tomato Seedlings ◽  
Physiological Disorders ◽  
Air Temperatures ◽  
Temperature Regimes ◽  
Leaf Chlorosis

Providing continuous light (24-h photoperiod) at a relatively low photosynthetic photon flux (PPF) is one possible way to reduce both initial and operational costs for lighting and cooling during transplant production with an artificial light. However, physiological disorders (i.e., chlorosis and necrosis) are often observed in several species under continuous light with a constant temperature. The objective of this study was to find an effective air-temperature regime under the continuous light to avoid such physiological disorders, and simultaneously enhance floral development, using tomato [Lycopersicon esculentum Mill.] as a model. The seedlings with fully expanded cotyledons were grown for 15 d at a PPF of 150 μmol·m–2·s–1, a relative humidity of 70%, and a CO2 concentration of about 380 μmol·mol–1 (atmospheric standard). Leaf chlorosis was observed when the air temperature was constant regardless of average air temperature (16, 22,or 28 °C). Neither leaf chlorosis nor necrosis was observed when the air temperatures were alternated [periods of high (28 °C) and low (16 °C) air temperatures of 16/8, 12/12, and 8/16 h·d–1]. Faster floral development was observed in the seedlings grown at lower average air temperatures. These results indicated that physiological disorders of tomato seedlings grown under continuous light could be avoided, and at the same time floral development could be enhanced, by lowering the average air temperature through modification of the periods of high and low air temperatures.

THE EFFECT OF SUPPLEMENTAL LIGHTING ON WINTER FLOWERING OF TRANSPLANTED Gypsophila paniculata

1986 ◽  
Vol 66 (3) ◽  
pp. 653-658 ◽  
Author(s):  
P. R. HICKLENTON
Keyword(s):  
High Pressure ◽  
Vegetative Growth ◽  
Photon Flux ◽  
Photosynthetic Photon Flux ◽  
Night Time ◽  
Low Level ◽  
Long Day ◽  
Gypsophila Paniculata ◽  
Production Strategies ◽  
Supplemental Lighting

Flowering of Gypsophila paniculata L. ’Bristol Fairy’ was promoted by supplemental lighting during the period September to February (fall) and January to June (spring) in greenhouses at latitude 45°N. Plants which received 42 or 63 d of night-time supplemental photosynthetic photon flux (PPF: 2000–0700 h; 93 μmol s−1 m−2 from high pressure sodium lamps) prior to transplanting flowered earlier and showed more vigorous vegetative growth than those subjected to only 21 d of supplemental PPF. Flowering did not occur in the fall crop for plants which received only low-level photoperiod extension lighting (8 μmol s−1 m−2, 2000–0700 h). Flowering in this cultivar is closely related to PPF during production as well as to photoperiod. Production strategies for northern greenhouses involving supplemental lighting treatments to plants prior to transplanting are suggested by these results.Key words: Gypsophila paniculata, supplemental lighting, flowering, long-day plant

scholarly journals Optimization of Photosynthetic Photon Flux Density and Light Quality for Increasing Radiation-Use Efficiency in Dwarf Tomato under LED Light at the Vegetative Growth Stage

Plants ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 121
Author(s):  
Xinglin Ke ◽  
Hideo Yoshida ◽  
Shoko Hikosaka ◽  
Eiji Goto
Keyword(s):  
Vegetative Growth ◽  
Growth Stage ◽  
Light Quality ◽  
Dry Mass ◽  
Photosynthetic Photon Flux Density ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Photosynthetic Photon Flux ◽  
Use Efficiency ◽  
Radiation Use

Dwarf tomatoes are advantageous when cultivated in a plant factory with artificial light because they can grow well in a small volume. However, few studies have been reported on cultivation in a controlled environment for improving productivity. We performed two experiments to investigate the effects of photosynthetic photon flux density (PPFD; 300, 500, and 700 μmol m−2 s−1) with white light and light quality (white, R3B1 (red:blue = 3:1), and R9B1) with a PPFD of 300 μmol m−2 s−1 on plant growth and radiation-use efficiency (RUE) of a dwarf tomato cultivar (‘Micro-Tom’) at the vegetative growth stage. The results clearly demonstrated that higher PPFD leads to higher dry mass and lower specific leaf area, but it does not affect the stem length. Furthermore, high PPFD increased the photosynthetic rate (Pn) of individual leaves but decreased RUE. A higher blue light proportion inhibited dry mass production with the same intercepted light because the leaves under high blue light proportion had low Pn and photosynthetic light-use efficiency. In conclusion, 300 μmol m−2 s−1 PPFD and R9B1 are the recommended proper PPFD and light quality, respectively, for ‘Micro-Tom’ cultivation at the vegetative growth stage to increase the RUE.

scholarly journals Branching of Chrysanthemum Cultivars Varies with Season, Temperature, and Photosynthetic Photon Flux

HortScience ◽  
1996 ◽  
Vol 31 (1) ◽  
pp. 74-78 ◽  
Author(s):  
Richard K. Schoellhorn ◽  
James E. Barrett ◽  
Terril A. Nell
Keyword(s):  
Linear Relationship ◽  
Air Temperature ◽  
Environmental Conditions ◽  
Root Zone ◽  
Lateral Branch ◽  
Photon Flux ◽  
Photosynthetic Photon Flux ◽  
Lateral Shoot ◽  
Commercial Cultivars ◽  
Lateral Branches

Effects of photosynthetic photon flux (PPF) and temperature on quantitative axillary budbreak and elongation of pinched chrysanthemum [Dendranthema ×grandiflorum (Ramat.) Kitamura] plants were studied in three experiments. In Expt. 1, 12 commercial cultivars were compared under fall and spring environmental conditions. Spring increases in lateral shoot counts were attributable to increased PPF and air temperature. Cultivars varied from 0 to 12 lateral branches per pinched plant and by as much as 60% between seasons. There was a linear relationship between lateral branches >5 cm at 3 weeks after pinching and final branch count (y = 0.407 + 0.914(x), r2 = 0.92). In Expt. 2, air was at 20 or 25C and the root zone was maintained at 5, 0, or –5C relative to air temperature. With air at 20C, lateral branch counts (3 weeks after pinch) declined by ≤50% with the medium at 15C relative to 25C. At 25C, lateral branch count was lower with medium at 30C than at 20C. Cultivars differed in their response to the treatments. Experiment 3 compared the interactions among temperature, PPF, and cultivar on lateral branch count. Depending on cultivar, the count increased the higher the PPF between 400 and 1400 μmol·m–2·s–1. Air temperature had no effect on lateral branch count. PPF had a stronger effect on lateral branch count than air temperature, and cultivars differed in their response.

Effect of NPK on vegetative growth, flowering and yield of chrysanthemum (Dendranthema grandiflora Ramat)

2017 ◽  
Vol 2 (02) ◽  
pp. 110-117
Author(s):  
Joginder Singh ◽  
Rashmi Nigam ◽  
Manoj Nazir ◽  
Anant Kumar ◽  
Harpal Singh
Keyword(s):  
Vegetative Growth ◽  
Field Investigation ◽  
Optimum Amount ◽  
Dendranthema Grandiflora ◽  
Flower Bud ◽  
Flower Stalk ◽  
Flower Yield ◽  
Number Of Leaves ◽  
Stalk Length ◽  
Number Of Branches

A field experiment on chrysanthemum cv. Birbal Sahni was conducted for revealed the Effect of NPK on vegetative growth, flowering and yield of chrysanthemum (Dendranthema grandiflora Ramat) at Department of Horticulture, C. C. S. University, Meerut, U.P., India for the field investigation with optimum amount of inorganic fertilizers with three increasing levels of NPK i.e. N1 (100 kg N2 + 60 kg P2O5 + 40 kg K2O/ ha), N2 (150 kg N2 +120 kg P2O5 + 80 kg K2O/ ha) and N3 (200 kg N2 + 180 kg P2O5 + 120 kg K2O/ ha). Maximum plant height (cm), plant spread (cm), diameter of main stem (cm), number of leaves/ plant, number of branches/ plant, number of flowers/ plant, flower weight/ plant (g), Flower yield (q/ ha), shelf life (days) observed with amount of N3 (200 kg N2 + 180 kg P2O5 + 120 kg K2O/ ha) spread (cm). The minimum days recorded for days taken to appearance of first flower bud and days taken to flowering and also NPK level N3 significantly affected the flower stalk length (cm) and flower size (cm) in chrysanthemum cv. Birbal Sahni during the investigation.

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