Bottom-Illuminated Orbital Shaker for Microalgae Cultivation

AbstractA bottom-illuminated orbital shaker designed for the cultivation of microalgae suspensions is described in this open-source hardware report. The instrument agitates and illuminates microalgae suspensions grown inside flasks. It was optimized for low production cost, simplicity, low power consumption, design flexibility, consistent, and controllable growth light intensity.The illuminated orbital shaker is especially well suited for low-resource research laboratories and education. It is an alternative to commercial instruments for microalgae cultivation. It improves on typical do-it-yourself microalgae growth systems by offering consistent and well characterized illumination light intensity. The illuminated growth area is 20 cm × 15 cm, which is suitable for three T75 tissue culture flasks or six 100 ml Erlenmeyer flasks. The photosynthetic photon flux density, is variable in eight steps (26 – 800 μmol · m−2 · s−1) and programmable in a 24-hour light/dark cycle. The agitation speed is variable (0 – 210 RPM). The overall material cost is around £300, including an entry-level orbital shaker. The build takes two days, requiring electronics and mechanical assembly capabilities. The instrument build is documented in a set of open-source protocols, design files, and source code. The design can be readily modified, scaled, and adapted for other orbital shakers and specific experimental requirements.The instrument function was validated by growing fresh-water microalgae Desmodesmus quadricauda and Chlorella vulgaris. The cultivation protocols, microalgae growth curves, and doubling times are included in this report.Specifications table

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Plant buffering against the high-light stress-induced accumulation of CsGA2ox8 transcripts via alternative splicing to finely tune gibberellin levels and maintain hypocotyl elongation

Horticulture Research ◽

10.1038/s41438-020-00430-w ◽

2021 ◽

Vol 8 (1) ◽

Author(s):

Bin Liu ◽

Shuo Zhao ◽

Pengli Li ◽

Yilu Yin ◽

Qingliang Niu ◽

...

Keyword(s):

Alternative Splicing ◽

Light Intensity ◽

Intron Retention ◽

Light Stress ◽

Photosynthetic Photon Flux Density ◽

Photon Flux ◽

Photon Flux Density ◽

Rna Seq ◽

Multiple Transcripts ◽

Novel Transcript

AbstractIn plants, alternative splicing (AS) is markedly induced in response to environmental stresses, but it is unclear why plants generate multiple transcripts under stress conditions. In this study, RNA-seq was performed to identify AS events in cucumber seedlings grown under different light intensities. We identified a novel transcript of the gibberellin (GA)-deactivating enzyme Gibberellin 2-beta-dioxygenase 8 (CsGA2ox8). Compared with canonical CsGA2ox8.1, the CsGA2ox8.2 isoform presented intron retention between the second and third exons. Functional analysis proved that the transcript of CsGA2ox8.1 but not CsGA2ox8.2 played a role in the deactivation of bioactive GAs. Moreover, expression analysis demonstrated that both transcripts were upregulated by increased light intensity, but the expression level of CsGA2ox8.1 increased slowly when the light intensity was >400 µmol·m−2·s−1 PPFD (photosynthetic photon flux density), while the CsGA2ox8.2 transcript levels increased rapidly when the light intensity was >200 µmol·m−2·s−1 PPFD. Our findings provide evidence that plants might finely tune their GA levels by buffering against the normal transcripts of CsGA2ox8 through AS.

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Influences of Shading and Fall Fertilization on Fluorescence, Freeze Resistance, Flower Production and Growth of Rhododendron ×kurume ‘Pink Pearl’

Journal of Environmental Horticulture ◽

10.24266/0738-2898.30.1.28 ◽

2012 ◽

Vol 30 (1) ◽

pp. 28-34

Author(s):

Frank P. Henning ◽

Timothy J. Smalley ◽

Orville M. Lindstrom ◽

John M. Ruter

Keyword(s):

Light Intensity ◽

Dry Weight ◽

Fertilizer Application ◽

High Rate ◽

Photon Flux ◽

Photon Flux Density ◽

Freeze Resistance ◽

Time Period ◽

Shade Cloth ◽

Main Plot

We investigated the influences of fall fertilization and light intensity on photosynthesis and freeze resistance of Rhododendron ×kurume ‘Pink Pearl’, an evergreen azalea cultivar, grown outdoors in containers under nursery conditions. The study included two main-plot fall fertilization treatments: 1) 0.5 liter solution containing 75 mg·liter−1 N applied for 60 days from August 1 through September 29 and 2) 0.5 liter solution containing 125 mg·liter−1 N applied for 120 days from August 1 through November 28, and four subplot light intensity treatments 1) 100% ambient photon flux density (PPFD) from May 1, 2004, through May 1, 2005, 2) shade fabric rated to reduce PPFD by 50% from May 1 through September 30, 2004, followed by 100% PPFD from October 1, 2004, through May 1, 2005, 3) 100% PPFD from May 1 through September 30, 2004, followed by 50% PPFD from October 1, 2004, through May 1, 2005, and 4) 50% PPFD from May 1, 2004, through May 1, 2005. Fertilizer application and shade treatments did not interact in their effects on stem freeze resistance or the timing of anthesis. The high rate of extended fertigation (125 mg·liter−1 N applied August 1 through September 28) reduced freeze resistance of azalea stems and advanced anthesis by 4.9 days compared to plants that received moderate fertigation (75 mg·liter−1 N from August 1 through September 29). The high rate of extended fall fertigation failed to increase leaf or stem dry weight compared to plants that received the moderate rate of fertigation. Plants grown in 50% PPFD from May 1 through September 30 produced 163% more above ground dry weight compared to plants grown in 100% light during the same time period. The addition or removal of shade cloth beginning October 1 failed to enhance azalea stem freeze resistance compared to plants that were only exposed to 100 or 50% PPFD respectively. Shade treatments affected the chlorophyll fluorescence ratio (Fv · Fm−1) of leaves, but leaf fluorescence was unrelated to stem freeze resistance. Shade treatments affected azalea growth and photosynthetic stress, but shade neither interacted with fall fertilization to increase stem freeze resistance, nor had a biologically significant effect on stem freeze resistance.

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Interaction of Light Intensity and CO2 Concentration Alters Biomass Partitioning in Chrysanthemum

Journal of Horticultural Research ◽

10.2478/johr-2021-0015 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Maral Hosseinzadeh ◽

Sasan Aliniaeifard ◽

Aida Shomali ◽

Fardad Didaran

Keyword(s):

Light Intensity ◽

Growth Management ◽

Growth Yield ◽

Dry Weight ◽

Co2 Concentration ◽

Photosynthetic Photon Flux Density ◽

Biomass Partitioning ◽

Photon Flux ◽

Photon Flux Density ◽

Vegetative Organs

Abstract Biomass partitioning is one of the pivotal determinants of crop growth management, which is influenced by environmental cues. Light and CO2 are the main drivers of photosynthesis and biomass production in plants. In this study, the effects of CO2 levels: ambient 400 ppm (a[CO2]) and elevated to 1,000 ppm (e[CO2]) and different light intensities (75, 150, 300, 600 μmol·m−2·s−1 photosynthetic photon flux density – PPFD) were studied on the growth, yield, and biomass partitioning in chrysanthemum plants. The plants grown at higher light intensity had a higher dry weight (DW) of both the vegetative and floral organs. e[CO2] diminished the stimulating effect of more intensive light on the DW of vegetative organs, although it positively influenced inflorescence DW. The flowering time in plants grown at e[CO2] and light intensity of 600 μmol·m−2·s−1 occurred earlier than that of plants grown at a[CO2]. An increase in light intensity induced the allocation of biomass to inflorescence and e[CO2] enhanced the increasing effect of light on the partitioning of biomass toward the inflorescence. In both CO2 concentrations, the highest specific leaf area (SLA) was detected under the lowest light intensity, especially in plants grown at e[CO2]. In conclusion, elevated light intensity and CO2 direct the biomass toward inflorescence in chrysanthemum plants.

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Effects of photon flux density on photosynthesis, growth, flowering, and oil content in Boronia

Australian Journal of Agricultural Research ◽

10.1071/a97144 ◽

1998 ◽

Vol 49 (5) ◽

pp. 791 ◽

Cited By ~ 1

Author(s):

J. M. Wann ◽

R. Orifici ◽

Z. E. Spadek ◽

J. A. Plummer

Keyword(s):

Light Intensity ◽

Flux Density ◽

Oil Content ◽

Natural Habitat ◽

Volatile Oil ◽

Photon Flux ◽

Photon Flux Density ◽

Cut Flowers ◽

Eucalyptus Marginata ◽

Full Sunlight

Boronia heterophylla is cultivated for cut flowers and B. megastigma for volatile oil production. Both species are endemic to south-western Western Australia and their natural habitat is often shaded by a canopy of Melaleuca parviflora or Eucalyptus marginata. Shade tents were used to examine the influence of reduced photon flux density (PFD) on photosynthesis, growth, and flower production in B. heterophylla and B. megastigma. Volatile oil content was also examined in B. megastigma. Photosynthesis in field-grown B. heterophylla was saturated at 16·2 µmol CO2/m 2·s under a PFD of 1022 µmol/m 2·s (75% full sunlight). Flower number was highest under 75% full sunlight but the number of harvestable stems was the same under 75% and full sunlight. More flowers were produced by B. megastigma plants grown under 75% full sunlight. Content of α-pinene and limonene decreased with decreasing light intensity, whereas β-ionone and docecyl acetate increased with decreasing light intensity

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Growing lettuce under multispectral light-emitting diodes lamps with adjustable light intensity

Italian Journal of Agronomy ◽

10.4081/ija.2017.883 ◽

2017 ◽

Vol 11 ◽

Cited By ~ 3

Author(s):

Giacomo Tosti ◽

Paolo Benincasa ◽

Rossano Cortona ◽

Beatrice Falcinelli ◽

Michela Farneselli ◽

...

Keyword(s):

Light Intensity ◽

Conversion Efficiency ◽

Light Emitting Diodes ◽

Biomass Conversion ◽

High Energy ◽

Photon Flux ◽

Photon Flux Density ◽

Light Emitting ◽

Light Spectra ◽

Use Efficiency

Light-Emitting Diodes (LEDs) technology offers vast possibilities in plant lighting due to its ability to mix different light frequencies, high energy use efficiency and low heat production combined to long lifespan. In particular, the combined effect of the Blue:Red (B:R) ratio and other frequencies in the central part of the PAR spectrum (CGA, i.e. cyan, green and amber) may be very important, though literature information is scarce. In this paper, the effects of six light spectra from LED technology were tested, i.e.: (i) B:R=0.82 (i.e. similar to sunlight) with CGA (treatment T0), (ii) B:R=0.82 without CGA (T1), (iii) red prevalence (B:R=0.25) without CGA (T2), (iv) blue prevalence (B:R=4) without CGA (T3), (v) red prevalence with CGA (T4) and (vi) blue prevalence with CGA (T5). The experiment was carried out in a walk-in climatic chamber with controlled temperature and relative humidity and an incident PAR photon flux density (PFD) of 300 μmol m–2 s–1 (14/10 light/dark photoperiod), generated by multispectral LED lamps with adjustable light intensity. Smooth leaved lettuce (Lactuca sativa L. cv Gentilina) was used as the test plant and biomass yield (DW, g m–2), LAI, soil coverage proportion (SC%), energy-biomass conversion efficiency (E-BCE, kWh g–1) and Radiation Use Efficiency (RUE, g mol–1 photons) were determined. Treatments with red predominance (T2 and T4) showed the highest SC% rates, while those with blue predominance (T3 and T5) showed the lowest. Light spectrum also affected leaf size (i.e. mean leaf area). The highest DW and RUE were observed in T2 and T4, followed by T0, while biomass in T3 and T5 was significantly lower (similar to T1). LAI values were generally high, but treatments with blue predominance showed the lowest LAI values (both with or without CGA). The introduction of intermediate wavelengths (green, cyan and amber) did not bring about significant improvement in DW or RUE, but resulted in reduced energy-biomass conversion efficiency, mainly due to lower architectural efficiency of the CGA LEDs. Future research should clarify how to optimise the light spectra according to the crop growth phases. The adoption of spectra promoting fast growth is fundamental in the early growth, while the use of spectra maximising yield quality may be more important later on.

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The Effect of Light Intensity on Vegetative Propagation Efficacy, Growth, and Morphology of “Albion” Strawberry Plants in a Precision Indoor Propagation System

Applied Sciences ◽

10.3390/app10031044 ◽

2020 ◽

Vol 10 (3) ◽

pp. 1044

Author(s):

Xiangnan Xu ◽

Ricardo Hernández

Keyword(s):

Light Intensity ◽

Open Field ◽

Disease Transmission ◽

Dry Mass ◽

Photosynthetic Photon Flux Density ◽

Fresh Mass ◽

Photon Flux ◽

Photon Flux Density ◽

Indoor Propagation ◽

Stock Plant

Open-field strawberry propagation is faced with several challenges such as lack of daughter plants, low quality, and disease transmission. Propagating strawberry plants in a completely enclosed controlled environment using a precision indoor propagation (PIP) system could overcome some of the challenges seen in open-field strawberry propagation. Optimizing the light intensity in a PIP system improves plant growth and reduce propagation cost. In the present study, “Albion” strawberry plants were grown as stock plants in a PIP system to examine plant propagation efficacy under three light intensities, PPF-250 (241 ± 13), PPF-350 (337 ± 13), or PPF-450 (443 ± 17) photosynthetic photon flux density (PPFD, μmol m−2 s−1) at 12 h photoperiod. They were grown under 25.7 ± 0.05 °C temperature, 0.95 ± 0.04 kPa vapor pressure deficit, and 73% ± 5.2% relative humidity. The number of daughter plants, morphology, and growth were recorded weekly (non-destructive measurements) for two intervals (01 to 12 weeks and 12 to 21 weeks). The number, total dry mass, and total fresh mass of daughter plants per stock plant increased with the increase in light intensity. The propagation efficacy to light ranged between 0.3 and 1.9 daughter plants per mole of light, depending on light intensity and harvest time. The number of daughter plants per week was estimated to be 36.2 plants wk−1 m−2. Daughter plants were classified by size and size was not influenced by the light treatment. Stock plant crown diameter, leaf area, fresh mass, dry mass, and leaf count all increased with an increase in PPFD. The shoot dry mass percent distribution to the daughter plant was 45% to 46% and was not affected by light intensity treatment. This study demonstrates the feasibility of using PIP systems for the production of strawberry daughter plants.

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Impact of Light Intensity and Nitrogen of Nutrient Solution on Nitrate Content in Three Lettuce Cultivars Prior to Harvest

Journal of Agricultural Science ◽

10.5539/jas.v10n6p99 ◽

2018 ◽

Vol 10 (6) ◽

pp. 99 ◽

Cited By ~ 5

Author(s):

Khurshid Ahmed Khan ◽

Zhengnan Yan ◽

Dongxian He

Keyword(s):

Light Intensity ◽

Nutrient Solution ◽

Nitrogen Supply ◽

Leafy Vegetables ◽

Photon Flux ◽

Photon Flux Density ◽

Nitrate Content ◽

High Accumulation ◽

Important Indicator ◽

Fluorescent Lamps

Nitrate smoothly accumulates in leafy vegetables and poses serious health hazards if connected excessively in the human diet. The objective of this study was to improve the cultivation method of low nitrate lettuce grown in plant factory. A substantial decrease of nitrate content (NO3-) in three lettuce cultivars were subjected by short-term pre-harvest treatment combined with lowing nitrogen supply of nutrient solution to half concentration and high photosynthetic photon flux density (PPFD) by LED lighting. The lettuce (Lactuca sativa L. cv. Frill ice, Lvzhu, Ziwei) were hydroponically grown in full strength of nutrient solution based on Yamasaki formula up to harvest time within a controlled environment under two light sources using fluorescent lamps and LEDs. The results demonstrated that a subsequent 3-days treatment of additional PPFD from 250 µmol m-2 s-1 to 350 µmol m-2 s-1 from 18 days after transplanting and half concentrations of nitrogen (NO3--N) in nutrient solution which is composition to standard resulted in the decrease of nitrate content as compared to plants grown under initial PPFD and full concentration of NO3--Ncomposition. The gradual decrease in nitrate content was accompanied by an increased concentration of nutritionally carbohydrates. Another important indicator of nutritional quality such as vitamin C content exhibited some variation, fresh weight of cultivars in cv. Frill ice and Ziwei observed higher with fluorescent lamps and for cv. Lvzhu with LED treatment section followed by lowest nitrate content of fresh leaves, respectively. Further, presented results disclosed that to avoid high accumulation of nitrate in leafy vegetables, the strategy of lowering nitrogen supply and increasing light intensity prior to harvest benefiting growers and consumers by improving quality of the product also making it consumer friendly.

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Gas Exchange of Four Cassava Cultivars in Relation to Light Intensity

Experimental Agriculture ◽

10.1017/s001447970000079x ◽

1982 ◽

Vol 18 (4) ◽

pp. 375-382 ◽

Cited By ~ 5

Author(s):

Jairo A. Palta

Keyword(s):

Gas Exchange ◽

Light Intensity ◽

Flux Density ◽

Direct Effect ◽

Photosynthetic Rate ◽

Photosynthetic Apparatus ◽

Photon Flux ◽

Photon Flux Density ◽

Light Saturation ◽

Effect Of Light

SUMMARYGas exchange measurements were carried out on four cassava cultivars, M. COL22, M. MEX59, M. COL638, and M. VEN218, under a range of light intensities, to investigate possible differences in photosynthesis and transpiration. Over the range of photon flux density 100–1500 μE m−2 s−1 leaves showed a light saturation response typical of C-3 plants with little increase in photosynthetic rate above 1000–1500 μE m−2 s−1 (200–300 Wm−2 PAR). At light saturation there were significant differences in photosynthetic rates between cultivars, with the highest 10% greater than the lowest. Part of the response could be attributed to increased stomatal aperture, and a greater part to a direct effect of light intensity on the photosynthetic apparatus. Transpiration increased with light intensity levels, but no significant differences were observed between cultivars.

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Optimization of Light Intensity, Temperature, and Nutrients to Enhance the Bioactive Content of Hyperforin and Rutin in St. John’s Wort

Molecules ◽

10.3390/molecules25184256 ◽

2020 ◽

Vol 25 (18) ◽

pp. 4256

Author(s):

Chia-Hung Kuo ◽

Yi-Chin Chou ◽

Kuo-Chun Liao ◽

Chwen-Jen Shieh ◽

Tzu-Shing Deng

Keyword(s):

Light Intensity ◽

Nutrient Solution ◽

Solution Concentration ◽

Photon Flux ◽

Photon Flux Density ◽

Optimal Conditions ◽

Active Ingredients ◽

St John’S Wort ◽

St John's Wort ◽

Maximum Content

St. John’s wort (Hypericum perforatum L.) is a medicinal plant that alleviates depression and other disorders due to its abundance of active ingredients. Hyperforin, rutin, and melatonin are the main active, and important, ingredients in St. John’s wort that alleviate depression. In order to investigate the optimal conditions for accumulating these active ingredients, design of experiments and response surface methodology (RSM) was employed in this study. Two-month-old St John’s wort plants were cultivated in growth chambers at varying temperatures, light intensities, and nutrient solution concentrations before analysis by HPLC, for determining differences in hyperforin, rutin, and melatonin content. The results showed that hyperforin and rutin contents were significantly influenced by temperature (18–23 °C) and light intensity (49–147 μmol m−2 s−1 photosynthetic photon flux density (PPFD)), whereas Hoagland’s nutrient solution concentration (25–75%) had little effect. The accumulation of melatonin might not be influenced by cultivation conditions. Light intensity and temperature are easily controlled environmental factors in artificial cultivation, both of which are related to secondary metabolite production in the plant. Based on RSM, the optimal conditions for the accumulation of hyperforin and rutin were obtained. The maximum content of hyperforin was 5.6 mg/g, obtained at a temperature of 19 °C, a nutrient solution concentration of 45%, and a light intensity of 49 μmol m−2 s−1 PPFD. The maximum content of rutin was 3.8 mg/g obtained at a temperature of 18 °C, a nutrient solution concentration of 50%, and a light intensity of 147 μmol m−2 s−1 PPFD. This evaluation of suitable conditions for the accumulation of bioactive compounds in St. John’s wort can be applied to plant factories on a large scale.

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Differential Effects of Low Light Intensity on Broccoli Microgreens Growth and Phytochemicals

Agronomy ◽

10.3390/agronomy11030537 ◽

2021 ◽

Vol 11 (3) ◽

pp. 537

Author(s):

Meifang Gao ◽

Rui He ◽

Rui Shi ◽

Yiting Zhang ◽

Shiwei Song ◽

...

Keyword(s):

Light Intensity ◽

Soluble Sugar ◽

Dry Weight ◽

Photosynthetic Photon Flux Density ◽

Carotenoid Content ◽

Photon Flux ◽

Photon Flux Density ◽

Artificial Light ◽

Plant Factory ◽

Phytochemical Contents

To produce high-quality broccoli microgreens, suitable light intensity for growth and phytochemical contents of broccoli microgreens in an artificial light plant factory were studied. Broccoli microgreens were irradiated under different photosynthetic photon flux density (PPFD): 30, 50, 70 and 90 μmol·m−2·s−1 with red: green: blue = 1:1:1 light-emitting diodes (LEDs). The broccoli microgreens grown under 50 μmol·m−2·s−1 had the highest fresh weight, dry weight, and moisture content, while the phytochemical contents were the lowest. With increasing light intensity, the chlorophyll content increased, whereas the carotenoid content decreased. The contents of soluble protein, soluble sugar, free amino acid, flavonoid, vitamin C, and glucosinolates except for progoitrin in broccoli microgreens were higher under 70 μmol·m−2·s−1. Overall, 50 μmol·m−2·s−1 was the optimal light intensity for enhancement of growth of broccoli microgreens, while 70 μmol·m−2·s−1 was more feasible for improving the phytochemicals of broccoli microgreens in an artificial light plant factory.

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