scholarly journals 233 Effects of Photoperiod during Transplant Production under Artificial Lighting Conditions on Floral Development and Bolting of Spinacia oleracea L.

HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 482C-482
Author(s):  
Hyeon-Hye Kim ◽  
Changhoo Chun ◽  
Toyoki Kozai ◽  
Junya Fuse
Keyword(s):  
Production Process ◽  
Floral Development ◽  
Spinacia Oleracea ◽  
Stem Elongation ◽  
Value Added ◽  
Short Photoperiod ◽  
Artificial Light ◽  
Artificial Lighting ◽  
Lighting Conditions ◽  
Spinacia Oleracea L

Spinach (Spinacia oleracea L.) was chosen to demonstrate that value-added transplant can be relatively easily produced under artificial light in a closed system. Transplant production under artificial light was divided into three periods, and the photoperiod during each period was varied. It was found that the rate of floral development could be controlled by photoperiod treatments, although floral initiation itself could not be manipulated. Short photoperiod treatments retarded floral development and stem elongation. This occurred even when the transplants were transferred for transplanting to natural conditions with long days and high temperatures. In conclusion, by providing the short photoperiod during the transplant production process, marketable plants with negligible bolting can be produced under natural long-day conditions. Moreover, the production cost per transplant in summer could be reduced by using a combination of natural and artificial lighting during the transplant production process. These results open the possibility to produce value-added transplants of different species under artificial lighting conditions and control their floral development and/or stem elongation for a timely and profitable harvest.

scholarly journals The Potential Use of Photoperiod during Transplant Production under Artificial Lighting Conditions on Floral Development and Bolting, Using Spinach as a Model

HortScience ◽  
2000 ◽  
Vol 35 (1) ◽  
pp. 43-45 ◽  
Author(s):  
Hyeon-Hye Kim ◽  
Changhoo Chun ◽  
Toyoki Kozai ◽  
Junya Fuse
Keyword(s):  
Floral Development ◽  
Spinacia Oleracea ◽  
Stem Elongation ◽  
Artificial Light ◽  
Floral Initiation ◽  
Growth Phases ◽  
Artificial Lighting ◽  
Lighting Conditions ◽  
Long Day ◽  
Potential Use

Spinach (Spinacia oleracea L.) was chosen to demonstrate that the respective vegetative or reproductive conditions of transplants can be controlled in their early stages of development under artificial light in a closed system. Transplant production under artificial light was divided into three growth phases and the photoperiod during each of these phases was varied. The rate of floral development was controlled by photoperiod, but floral initiation itself was not affected. Short photoperiod treatments (8 or 12 hours/day) retarded floral development and stem elongation (bolting). This delay continued even after the transplants were transferred to natural long-day (15.5 hours/day on average) conditions with high temperatures (17 and 37 °C minimum and maximum). We concluded that by using short photoperiods during transplant production, marketable plants with reduced bolting could be produced under natural long-day conditions. In Japan, spinach with this rosetting capacity would be of greater value. Further, this concept opens the possibility of producing better quality transplants of several species under artificial lighting conditions of appropriate length, and thereby controlling their floral development and/or bolting.

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.

Reconstructing Artificial Light in Ancient Greece

2017 ◽  
Author(s):  
Dorina Moullou ◽  
Fragiskos V. Topalis
Keyword(s):  
Experimental Data ◽  
Optical Properties ◽  
Ancient Greece ◽  
Artificial Light ◽  
Light Sources ◽  
Colour Discrimination ◽  
Colour Perception ◽  
Relative Ease ◽  
Artificial Lighting ◽  
Lighting Conditions

This chapter presents an overview of artificial lighting means and their efficiency in the performance of domestic nocturnal activities (except cult practices) in ancient Greece. Through experiments conducted in the Lighting Laboratory of the National Technical University of Athens, the optical properties of exact copies of ancient light sources are investigated. The experimental data are used to assess the sufficiency of light produced by the lighting devices, and to examine the resulting lighting conditions in relation to colour perception and domestic nocturnal activities. The results show that people in antiquity could move around and operate with relative ease at night. Most domestic nocturnal activities could be performed even by the light of a single lamp, provided that it was located relatively nearby. Activities involving colour discrimination, such as weaving, were the most difficult but not impossible to perform. Therefore, artificial light in antiquity could be both effective and economical.

scholarly journals Orb-weaving spiders are fewer but larger and catch more prey in lit bridge panels from a natural artificial light experiment

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e8808 ◽  
Author(s):  
Dylan G.E. Gomes
Keyword(s):  
Urban Areas ◽  
Prey Capture ◽  
Trophic Levels ◽  
Artificial Light ◽  
Insect Communities ◽  
Artificial Lighting ◽  
Lighting Conditions ◽  
Insect Trap ◽  
Increased Risk ◽  
Web Building

Artificial light at night is rapidly changing the sensory world. While evidence is accumulating for how insects are affected, it is not clear how this impacts higher trophic levels that feed on insect communities. Spiders are important insect predators that have recently been shown to have increased abundance in urban areas, but have shown mixed responses to artificial light. On a single bridge with alternating artificially lit and unlit sections, I measured changes in the orb-weaving spider Larinioides sclopetarius (Araneidae) web abundance, web-building behavior, prey-capture, and body condition. In artificially lit conditions, spiders caught more prey with smaller webs, and had higher body conditions. However, there were fewer spiders with active webs in those lit areas. This suggests that either spiders were not taking advantage of an ecological insect trap, perhaps due to an increased risk of becoming prey themselves, or were satiated, and thus not as active within these habitats. The results from this natural experiment may have important consequences for both insects and spiders in urban areas under artificial lighting conditions.

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.

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