scholarly journals The Evaluation of Growth Performance, Photosynthetic Capacity, and Primary and Secondary Metabolite Content of Leaf Lettuce Grown under Limited Irradiation of Blue and Red LED Light in an Urban Plant Factory

Agriculture ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 28
Author(s):  
Md Obyedul Kalam Azad ◽  
Katrine Heinsvig Kjaer ◽  
Md Adnan ◽  
Most Tahera Naznin ◽  
Jung Dae Lim ◽  
...  
Keyword(s):  
Phenolic Compounds ◽  
Plant Growth ◽  
Growth Performance ◽  
Leaf Area ◽  
Photosynthetic Performance ◽  
Artificial Lighting ◽  
Energy Demands ◽  
Lighting Conditions ◽  
Plant Factory ◽  
Leaf Lettuce

Plant production in urban areas is receiving much attention due to its potential role in feeding the rapidly growing population of city dwellers. However, higher energy demands in urban plant factories are among the key challenges that need to be addressed. Artificial lighting is responsible for the most significant levels of energy consumption in plant factories; therefore, lighting systems must be modulated in consideration of the sustainable food–energy nexus. In this context, low light irradiation using blue (B) and red (R) LED was applied in a plant factory for the growth of red leaf lettuce (Lactuca sativa L. var Lollo rosso) to evaluate the growth performance and functional quality. The tested B (450 nm) and R (660 nm) light ratios were B/R = 5:1; 3:1; 1:1; 1:3, and 1:5, with a photosynthetic photon flux density (PPFD) of 90 ± 3 µmol m−2 s−1. In the plant factory, the photoperiod, temperature, RH, and CO2 conditions were 16 h d−1, 20 ± 0.5 °C, 65% ± 5%, and 360 ± 10 μL L−1, respectively. The lettuce was harvested 10 and 20 days after the commencement of LED light treatment (DAT). In this study, normal photosynthetic activity and good visual quality of the lettuce were observed. The results show that a higher fraction of R (B/R = 1:5) significantly increased plant growth parameters such as plant height, leaf area, specific leaf area, plant fresh and dry weight, and carbohydrate content. By contrast, a higher fraction of B (B/R = 5:1) significantly increased the photosynthetic parameters and contents of pigment and phenolic compounds. The rate of photosynthetic performance, carbohydrates (except starch), and content of phenolic compounds were highest after 10 DAT, whereas the pigment contents did not significantly differ at the different growth stages. It is concluded that high R fractions favor plant growth and carbohydrate content, while high B fractions favor photosynthetic performance and the accumulation of pigments and phenolic compounds in red leaf lettuce under limited lighting conditions. This study will help in designing artificial lighting conditions for plant factory production to reduce energy demands.

scholarly journals Supplementary Far-Red and Blue Lights Influence the Biomass and Phytochemical Profiles of Two Lettuce Cultivars in Plant Factory

Molecules ◽  
2021 ◽  
Vol 26 (23) ◽  
pp. 7405
Author(s):  
Yamin Li ◽  
Linyuan Wu ◽  
Haozhao Jiang ◽  
Rui He ◽  
Shiwei Song ◽  
...  
Keyword(s):  
Phenolic Compounds ◽  
Vitamin C ◽  
Chlorophyll A ◽  
Photon Flux ◽  
Total Phenolic ◽  
Total Flavonoids ◽  
Total Phenolic Compounds ◽  
Leaf Color ◽  
Plant Factory ◽  
Leaf Lettuce

Three different LED spectra (W: White light; WFR: W + far-red light; WB: W + blue light) with similar photosynthetic photon flux density (PPFD) were designed to explore the effects of supplementary far-red and blue lights on leaf color, biomass and phytochemicals of two cultivars of red-leaf lettuce (“Yanzhi” and “Red Butter”) in an artificial lighting plant factory. Lettuce plants under WB had redder leaf color and significantly higher contents of pigments, such as chlorophyll a, chlorophyll b, chlorophyll (a + b) and anthocyanins. The accumulation of health-promoting compounds, such as vitamin C, vitamin A, total phenolic compounds, total flavonoids and anthocyanins in the two lettuce cultivars were obviously enhanced by WB. Lettuce under WFR showed remarkable increase in fresh weight and dry weight; meanwhile, significant decreases of pigments, total phenolic compounds, total flavonoids and vitamin C were found. Thus, in the plant factory system, the application of WB can improve the coloration and quality of red leaf lettuce while WFR was encouraged for the purpose of elevating the yield of lettuce.

scholarly journals Continuous Irradiation with Alternating Red and Blue Light Enhances Plant Growth While Keeping Nutritional Quality in Lettuce

HortScience ◽  
2018 ◽  
Vol 53 (12) ◽  
pp. 1804-1809 ◽  
Author(s):  
Noriko Ohtake ◽  
Masaharu Ishikura ◽  
Hiroshi Suzuki ◽  
Wataru Yamori ◽  
Eiji Goto
Keyword(s):  
Plant Growth ◽  
Leaf Area ◽  
Blue Light ◽  
Nutritional Quality ◽  
Continuous Irradiation ◽  
Light Emitting ◽  
Artificial Lighting ◽  
Fluorescent Lamps ◽  
High Concentrations ◽  
Net Assimilation

Plant factories with artificial lighting have been developed to improve food production, functional ingredients, and profitability. Intensive research has been performed to elucidate the effects of light intensity and wavelength on plant growth and nutritional quality with the use of light-emitting diodes (LEDs). In particular, the effects of monochromatic red, blue, or simultaneous red + blue light have been studied because these wavelengths are predominantly used for photosynthesis. We examined the effects of alternating red and blue light provided by LEDs over a period of 24 hours on the growth and nutritional properties of leafy lettuce. The results clearly show that alternating red and blue light accelerated plant growth significantly compared with white fluorescent lamps or red and blue LEDs at the same daily light integral. Plants grown under alternating red/blue light had a greater net assimilation rate and total and projected leaf area (an indicator of the fraction of leaf area that absorbs more light) than other plants. Additionally, alternating red and blue light maintained high concentrations of sugars, ascorbic acid, and anthocyanins in leaves. Taken together, the results indicate that continuous irradiation with alternating red and blue light could enhance growth while maintaining the nutritional quality in lettuce.

scholarly journals A Combination of Downward Lighting and Supplemental Upward Lighting Improves Plant Growth in a Closed Plant Factory with Artificial Lighting

HortScience ◽  
2017 ◽  
Vol 52 (6) ◽  
pp. 831-835 ◽  
Author(s):  
Jyotsna Joshi ◽  
Geng Zhang ◽  
Shanqi Shen ◽  
Kanyaratt Supaibulwatana ◽  
Chihiro K.A. Watanabe ◽  
...  
Keyword(s):  
Plant Growth ◽  
Plant Production ◽  
Growth And Yield ◽  
Low Light ◽  
Planting Pattern ◽  
Cultivation System ◽  
Artificial Lighting ◽  
Plant Factory ◽  
Plant Yields ◽  
Lettuce Yield

“Plant factory with artificial lighting” (PFAL) refers to a plant production facility that can achieve mass production of vegetables year round in a controlled environment. However, the high-density planting pattern in PFALs causes low light conditions in the lower canopy, leading to leaf senescence in the outer leaves and thus to reductions in plant yields. In the present study, the effect of supplemental upward lighting underneath the plants on photosynthetic characteristics and plant yield was examined in lettuce, in comparison with supplemental downward lighting from above the plants at the same light intensity. Supplemental upward lighting increased the curvature factor of the photosynthetic response to light from above the plants. Moreover, supplemental upward lighting significantly enhanced the lettuce yield by retarding the senescence of the outer leaves. Here, we propose a novel cultivation system with a combination of downward lighting and supplemental upward lighting that can effectively increase plant growth and yield in PFALs.

Errors of In Situ Illuminance Measurements

2016 ◽  
Vol 824 ◽  
pp. 676-683
Author(s):  
Michaela Hlásková ◽  
Lenka Gábrová ◽  
František Vajkay
Keyword(s):  
Measurement Errors ◽  
Daily Basis ◽  
Lighting Design ◽  
Public Health Authority ◽  
Construction Work ◽  
Measurement Instruments ◽  
Artificial Lighting ◽  
Lighting Conditions ◽  
Overcast Sky

Lighting conditions in buildings are verified by experts on a daily basis. Such verifications may be done at several phases in various ways. In the field of daylighting, it is common to make an assessment within the pre-design and in-design phases of a construction work throughout calculations, only rarely by measurements. This approach is the opposite of artificial lighting design, which is done within the in-design phase by calculations and is verified by measurements in post-realization phase. The verification of artificial lighting design is required by the building and public health authority otherwise buildings cannot be approved to use. In the field of daylighting, measurements could be performed as well, nevertheless those are often problematic because regulations usually require fulfilments of the daylight factor which can be determined only under CIE overcast sky. Howbeit, both artificial lighting and daylighting measurements are influenced by many errors, e.g. errors of light measurement instruments, measurement conditions, measurement methods and human factor. The paper is focused on this aspect of lighting design, more specifically on the daylighting measurement errors.

scholarly journals Rock-Solubilizing Microbial Inoculums Have Enormous Potential as Ecological Remediation Agents to Promote Plant Growth

Forests ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 357
Author(s):  
Zhaohui Jia ◽  
Miaojing Meng ◽  
Chong Li ◽  
Bo Zhang ◽  
Lu Zhai ◽  
...  
Keyword(s):  
Plant Growth ◽  
Leaf Area ◽  
Ecological Restoration ◽  
Root Nodules ◽  
Robinia Pseudoacacia ◽  
Growth Index ◽  
Nodule Formation ◽  
Bare Rock ◽  
Mining Sites ◽  
Robinia Pseudoacacia L

Anthropogenic overexploitation poses significant threats to the ecosystems that surround mining sites, which also have tremendous negative impacts on human health and society safety. The technological capacity of the ecological restoration of mine sites is imminent, however, it remains a challenge to sustain the green restorative effects of ecological reconstruction. As a promising and environmentally friendly method, the use of microbial technologies to improve existing ecological restoration strategies have shown to be effective. Nonetheless, research into the mechanisms and influences of rock-solubilizing microbial inoculums on plant growth is negligible and the lack of this knowledge inhibits the broader application of this technology. We compared the effects of rock-solubilizing microbial inoculums on two plant species. The results revealed that rock-solubilizing microbial inoculums significantly increased the number of nodules and the total nodule volume of Robinia pseudoacacia L. but not of Lespedeza bicolor Turcz. The reason of the opposite reactions is possibly because the growth of R. pseudoacacia was significantly correlated with nodule formation, whereas L. bicolor’s growth index was more closely related to soil characteristics and if soil nitrogen content was sufficient to support its growth. Further, we found that soil sucrase activity contributed the most to the height of R. pseudoacacia, and the total volume of root nodules contributed most to its ground diameter and leaf area. Differently, we found a high contribution of total soil carbon to seedling height and ground diameter of L. bicolor, and the soil phosphatase activity contributed the most to the L. bicolor’ s leaf area. Our work suggests that the addition of rock-solubilizing microbial inoculums can enhance the supply capacity of soil nutrients and the ability of plants to take up nutrients for the promotion of plant growth. Altogether, our study provides technical support for the practical application of rock-solubilizing microbes on bare rock in the future.

scholarly journals Plant Growth Modulates Metabolites and Biological Activities in Retama raetam (Forssk.) Webb

Molecules ◽  
2018 ◽  
Vol 23 (9) ◽  
pp. 2177 ◽  
Author(s):  
Mariem Saada ◽  
Hanen Falleh ◽  
Marcelo Catarino ◽  
Susana Cardoso ◽  
Riadh Ksouri
Keyword(s):  
Phenolic Compounds ◽  
Plant Growth ◽  
Biological Activities ◽  
Reducing Power ◽  
Vegetative Stage ◽  
Total Phenolic ◽  
Human Pathogens ◽  
Retama Raetam ◽  
Physiological Stage ◽  
Main Class

This work focuses on the variability of Retama raetam (Forssk.) Webb bioactive compounds as a function of the plant cycle. The main results showed that it exhibited the highest percentage of polyunsaturated fatty acids, along with superior levels of vitamin C and total phenolic compounds (66.49%, 645.6 mg·100 g−1 FW and 23.9 mg GAE·g−1, respectively) at the vegetative stage. Instead, at the flowering and mature fruiting stages, R. raetam (Forssk.) Webb exhibited notable contents of proline (25.4 μmol·g−1 DW) and carotenoids (27.2 μg·g−1 FW), respectively. The gathered data concerning the antioxidant activity highlighted the effectiveness of the vegetative stage in comparison to the other periods. Actually, IC50 and EC50 values of the hydromethanolic extract obtained from the plant shoots at the vegetative stage were of 23, 380, 410, 1160 and 960 μg·mL−1 (DPPH• and ABTS•+ radicals scavenging activity, reducing power, chelating power and β-carotene bleaching activity, respectively). Furthermore, the four studied stages showed appreciable antibacterial capacities against human pathogens with a higher efficiency of the vegetative stage extract. Finally, the LC-DAD-ESI/MSn analysis revealed the predominance of isoflavonoids as main class of phenolic compounds and demonstrates that individual phenolic biosynthesis was clearly different as a function of plant growth. These findings highlight that reaching the optimum efficiency of R. raetam (Forssk.) Webb is closely linked to the physiological stage.

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