While continuous white LED lighting increases chlorophyll content (SPAD), green LED light reduces the infection rate of lettuce during storage and shelf-life conditions

AbstractThe objective of this study was to develop a mathematical model for the non-destructive, fast estimation of the leaf chlorophyll (Chl) content of pomegranate trees. For this reason, contact images of the leaf samples were firstly captured with smartphones and the RGB colours of the images were used for the estimation of the leaf Chl contents. Here, different methods were used for the contact imaging. In the present study, two closed boxes with a small hole (equal to the dimensions of a smartphone camera) on each were formed. Samples were inserted into the hole; and a red LED light and white LED light, separately, were passed through the hole and the leaf. Furthermore, a series of models were tested to best estimate the leaf chlorophyll content of the pomegranate trees by using the RGB colours of contact imaging. Results showed that the use of red LED light sources, instead of white LED light sources, during contact imaging, provides a better estimation of the leaf Chl content. Results also suggest that colour values are highly related to the total weight of the contact imaging area. According to the results obtained, the best estimation of the leaf Chl content (of a given area) is possible by using both the G and B colour values with multiple regression models. It is also found to be important to use the weight of the sampled area for the estimation of the leaf chlorophyll content in mg ∙ g−1.

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Low Oxygen Storage Improves Tomato Postharvest Cold Tolerance, Especially for Tomatoes Cultivated with Far-Red LED Light

Foods ◽

10.3390/foods10081699 ◽

2021 ◽

Vol 10 (8) ◽

pp. 1699

Author(s):

Fahrizal Yusuf Affandi ◽

Jan A. Verschoor ◽

Maxence J. M. Paillart ◽

Julian C. Verdonk ◽

Ernst J. Woltering ◽

...

Keyword(s):

Shelf Life ◽

Cold Tolerance ◽

Chilling Injury ◽

Oxygen Storage ◽

White Led ◽

Low Oxygen ◽

Led Light ◽

Red Led ◽

Oxygen Conditions ◽

Colour Development

We investigated the effects of low oxygen storage on chilling injury development, colour development, respiration and H2O2 levels of ‘Merlice’ tomatoes cultivated with and without far red (FR) LED lighting during 20 days of shelf-life. Mature green (MG) and red (R) tomatoes were stored at 2 °C in combination with 0.5, 2.5, 5 and 21 kPa O2 for 15 days (experiment 1). MG tomatoes cultivated under either white LED or white LED light with FR LED light were stored at 2 °C in combination with 1, 5 and 21 O2 kPa for 14 days (experiment 2). Chilled MG and R tomatoes from experiment 1 showed decay, firmness loss and higher weight loss during shelf-life which were reduced under low oxygen conditions. FR during cultivation improved chilling tolerance of MG tomatoes. Fastest colour development and lowest respiration rate during shelf-life were observed for MG fruit cultivated with FR lighting prior to storage at 1 kPa O2/0 kPa CO2. H2O2 levels during the shelf-life were not affected during cold storage. The improved cold tolerance of MG tomatoes cultivated with FR lighting is likely due to lower oxygen uptake that led to both higher lycopene synthesis and less softening.

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Growth of Lettuce (Lactucasativa L.) Plant Under Red-Blue-White Light and Grow Light LEDs in Plant Factory System

International Journal of Environment Agriculture and Biotechnology ◽

10.22161/ijeab.66.18 ◽

2021 ◽

Vol 6 (6) ◽

pp. 146-152

Author(s):

I Ketut Suada ◽

I Gede Putu Wirawan ◽

Rindang Dwiyani ◽

Linawati Linawati ◽

I Nyoman Setiawan ◽

...

Keyword(s):

Chlorophyll Content ◽

White Light ◽

Dry Weight ◽

White Led ◽

Fresh Weight ◽

Led Light ◽

Maximum Biomass ◽

Plant Factory ◽

Different Types ◽

Lettuce Growth

Indoor culture requires a variety of inputs to get maximum biomass. These inputs are the nutrients, temperature, humidity, and light which plants needed to photosynthesize. Different types of light have been studied and it is known that the same spectrum will give different responses by different plants. The purpose of this study was to find out the effect of red-blue-white light LED on lettuce growth compared to grow light LED as a control which commonly used in plant factory rooms. The red-blue-white light is arranged on a 100 cm long aluminum rod, mounted along the plant in a gully DFT hydroponic fed by 1000-2000 ppm nutrients of ABmix plus with a pH of 5.5-6.5. LED grow light provided the plant a significantly higher height of 16.30% compared to red-blue-white light, but was no different to the length of lettuce root. The number and the area of leaves in red-blue-white light were markedly higher at 16.67% and 33.78% respectively than grow light. In addition, the red-blue-white light increased the chlorophyll content, fresh weight, and dry weight of lettuce plants, by 25.00%, 101.49% and 58.13% consecutively. Therefore, these results suggested that the red-blue-white LED light provided a significant higher biomass than the grow light LED.

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Tuning luminescence of Ba3Si6O12N2:Eu2+ phosphor for full-spectrum warm white LED lighting

Journal of Alloys and Compounds ◽

10.1016/j.jallcom.2021.159377 ◽

2021 ◽

pp. 159377

Author(s):

Lili Liu ◽

Lei Chen ◽

Ruixiang Wang ◽

Yanfei Xiao ◽

Fengli Yang ◽

...

Keyword(s):

White Led ◽

Full Spectrum ◽

Led Lighting

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Antarctic krill (Euphausia superba) exhibit positive phototaxis to white LED light

Polar Biology ◽

10.1007/s00300-021-02814-7 ◽

2021 ◽

Vol 44 (3) ◽

pp. 483-489

Author(s):

Bjørn A. Krafft ◽

Ludvig A. Krag

Keyword(s):

Antarctic Krill ◽

Light Exposure ◽

Euphausia Superba ◽

Marine Species ◽

Artificial Light ◽

White Led ◽

Light Emitting ◽

Positive Phototaxis ◽

Led Light ◽

Exposure Experiment

AbstractThe use of light-emitting diodes (LEDs) is increasingly used in fishing gears and its application is known to trigger negative or positive phototaxis (i.e., swimming away or toward the light source, respectively) for some marine species. However, our understanding of how artificial light influences behavior is poorly understood for many species and most studies can be characterized as trial and error experiments. In this study, we tested whether exposure to white LED light could initiate a phototactic response in Antarctic krill (Euphausia superba). Trawl-caught krill were used in a controlled artificial light exposure experiment conducted onboard a vessel in the Southern Ocean. The experiment was conducted in chambers with dark and light zones in which krill could move freely. Results showed that krill displayed a significant positive phototaxis. Understanding this behavioral response is relevant to development of krill fishing technology to improve scientific sampling gear, improve harvest efficiency, and reduce potential unwanted bycatch.

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