LEDs for photons, physiology and food

Pattison, P. Morgan; Tsao, Jeffrey Y.; Brainard, George C.; Bugbee, Bruce

doi:10.1038/s41586-018-0706-x

Cited by 301 publications

(234 citation statements)

References 70 publications

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“…The rationale of LEDs in horticultural production is to support sustainable development, reduce carbon footprint and increase resource utilisation efficiency . LED lighting is more efficient compared to the traditional lighting sources used in horticulture and allows the light spectrum and intensity to be tailored to enhance plant performance and the light use efficiency when cultivating high‐value crops . Light is the sole source of energy for plant photosynthesis and growth; it also serves as a signal regulating plant morphogenesis, physiology and metabolism.…”

Section: Introductionmentioning

confidence: 99%

“…The positive effects of green, far‐red and UV‐A light are also recognised. However, little is known about the effects of different photosynthetic photon flux densities (PPFDs) of LEDs with different light spectra on plants as well as the interaction between the quality and quantity of light …”

Section: Introductionmentioning

confidence: 99%

“…Reasonable light quantity can promote photosynthesis and enhance biomass production, whereas excessive irradiation will cause the processes of photoprotection and photodamage in plants. Early studies with LEDs were performed at a PPFD of less than 10% of full sunlight (200 μmol m −2 s −1 ) . Research results have shown that plant net photosynthetic rate generally increases with increasing PPFD; however, it is gradually saturated at high PPFD, and then light use efficiency decreases.…”

Section: Introductionmentioning

confidence: 99%

“…1,2 LED lighting is more efficient compared to the traditional lighting sources used in horticulture and allows the light spectrum and intensity to be tailored to enhance plant performance and the light use efficiency when cultivating high-value crops. [3][4][5] Light is the sole source of energy for plant photosynthesis and growth; it also serves as a signal regulating plant morphogenesis, physiology and metabolism. Moreover, plants are highly sensitive to the spectrum and intensity of light.…”

Section: Introductionmentioning

confidence: 99%

“…However, little is known about the effects of different photosynthetic photon flux densities (PPFDs) of LEDs with different light spectra on plants 7 as well as the interaction between the quality and quantity of light. 4 Reasonable light quantity can promote photosynthesis and enhance biomass production, whereas excessive irradiation will cause the processes of photoprotection and photodamage in plants. Early studies with LEDs were performed at a PPFD of less than 10% of full sunlight (200 μmol m −2 s −1 ).…”

Section: Introductionmentioning

confidence: 99%

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Lighting intensity and photoperiod serves tailoring nitrate assimilation indices in red and green baby leaf lettuce

et al. 2019

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BACKGROUND Understanding plant responses to light quantity in indoor horticultural systems is important for optimising lettuce growth and metabolism as well as energy utilisation efficiency. Light intensity and photoperiod sufficient for normal plant growth parameters might be not efficient for nitrate assimilation. Therefore, this study explored and compared the effects of different light intensities (100–500 μmol m−2 s−1) and photoperiods (12–24 h) on the growth and nitrate assimilation in red and green leaf lettuce (Lactuca sativa L.). RESULTS For efficient nitrate assimilation, 300–400 μmol m−2 s−1 photosynthetic photon flux density (PPFD) and 16–18 h photoperiod is necessary for red and green lettuces. The insufficient light quantity resulted in reduced growth and remarkable increase in nitrate and nitrite contents in both cultivars. Short photoperiods, similarly to low PPFD, growth parameters, chlorophyll indices and nitrate assimilation indices showed the shortage of photosynthetic products for normal plant physiological processes. Short photoperiods had the least pronounced effect on nitrate and nitrite contents in lettuce leaves. CONCLUSION Light intensity was superior compared to photoperiods for efficient nitrate assimilation in both lettuce cultivars. Under short photoperiods, similarly to low intensity, growth parameters, chlorophyll index and nitrate assimilation indices showed a shortage of photosynthetic products for normal physiological processes. The free amino acid concentration increased, but it was not efficiently incorporated in proteins, as their level in lettuce was lower compared to those for moderate photoperiods. © 2019 Society of Chemical Industry

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Lighting intensity and photoperiod serves tailoring nitrate assimilation indices in red and green baby leaf lettuce

et al. 2019

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Eu(II)‐Activated Silicates for UV Light‐Emitting Diodes Tuning into Warm White Light

et al. 2020

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White‐light‐emitting diodes (WLEDs) are the main white light source for general lighting due to high‐luminous efficacy (>150 lm W−1), long lifespan (5 × 104 h), and environmentally friendly properties. Despite the current maturity and reliability of the solid state‐lighting field, the control of the correlated color temperature (CCT) tuning is still a challenge, arising from the lack of red emission color in the current design of commercial WLEDs. Moreover, as this aspect is often associated with dysregulations of the human circadian rhythm, the need for novel WLEDs is of enlarged societal relevance. In this scope, herein, warm WLED prototypes are fabricated by coating near‐UV‐emitting LEDs with a mixture of the yellow‐emitting polyphasic Sr2SiO4:Eu(II) (S2S) and the blue‐emitting BaMgAl10O17:Eu(II) (BAM) phosphors dispersed in poly(methyl methacrylate). As the amount of S2S increases in the phosphor mixture, the CCT values of the WLEDs decrease from 6500 K (ideal for daylight application) to 4000 K (ideal for night light application), with a luminous efficacy of radiation of 404 lm W−1, among the best figures of merit for WLEDs. Furthermore, all the WLED devices also display a desirable color rendering index (CRI > 75), comparable with the commercial WLED, independent on the operating voltage.

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Novel Materials for Urban Farming

Zhang

et al. 2021

Advanced Materials

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Scarcity of natural resources, shifting demographics, climate change, and increasing waste are four major challenges in the quest to feed the exploding world population. These challenges serve as the impetus to harness novel technologies to improve agriculture, productivity, and sustainability. Urban farming has several advantages over conventional farming: higher productivity, improved sustainability, and the ability to provide fresh food all year round. Novel materials are key to accelerating the evolution of urban farming – with their ability to facilitate controlled release of nutrients and pesticides, improved seed health, substrates with better water retention capability, more efficient recycling of agricultural waste, and precise plant health monitoring. Materials science enables environmental sustainability and higher harvest yields in urban farms. Here, Singapore is used as an example of a land‐scarce city where urban farming may be the solution for future food production. Potential research directions and challenges in urban farming are highlighted, and how material optimization and innovation drive the development of urban farming to meet national and global food demands is briefly discussed. This review serves as a guide for researchers and a reference for stakeholders of urban farms, policy makers, and other interested parties.

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LEDs for photons, physiology and food

Cited by 301 publications

References 70 publications

Lighting intensity and photoperiod serves tailoring nitrate assimilation indices in red and green baby leaf lettuce

Lighting intensity and photoperiod serves tailoring nitrate assimilation indices in red and green baby leaf lettuce

Eu(II)‐Activated Silicates for UV Light‐Emitting Diodes Tuning into Warm White Light

Novel Materials for Urban Farming

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