scholarly journals Comparison of the Photoautotrophic Growth Regimens of Chlorella sorokiniana in a Photobioreactor for Enhanced Biomass Productivity

Biology ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 169
Author(s):  
Elvira E. Ziganshina ◽  
Svetlana S. Bulynina ◽  
Ayrat M. Ziganshin
Keyword(s):  
Large Scale ◽  
Basal Medium ◽  
Biomass Productivity ◽  
Chlorella Sorokiniana ◽  
Pigment Concentration ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Total Biomass ◽  
Initial Growth ◽  
Wide Range

Microalgae have a wide industrial potential because of their high metabolic diversity and plasticity. Selection of optimal cultivation methods is important to optimize multi-purpose microalgal biotechnologies. In this research, Chlorella sorokiniana AM-02 that was isolated from a freshwater lake was cultured under various high photosynthetic photon flux density (PPFD) conditions and CO2 gas levels in standard Bold’s basal medium (BBM). Furthermore, a wide range of nitrate levels (180–1440 mg L−1) was tested on the growth of C. sorokiniana. Microalgae growth, pigment concentration, medium pH, exit gas composition, as well as nitrate, phosphate, and sulfate levels were measured during an experimental period. The preferred high PPFD and optimal CO2 levels were found to be 1000–1400 μmol photons m−2 s−1 and 0.5–2.0% (v/v), respectively. The addition of nitrate ions (up to 1440 mg L−1) to the standard growth medium increased final optical density (OD750), cell count, pigment concentration, and total biomass yield but decreased the initial growth rate at high nitrate levels. Our findings can serve as the basis for a robust photoautotrophic cultivation system to maximize the productivity of large-scale microalgal cultures.

What Limits the Efficiency of Photosynthesis, and Can There Be Beneficial Improvements?

1998 ◽  
Author(s):  
J. Barber
Keyword(s):  
Carbon Dioxide ◽  
Molecular Mechanisms ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Sufficient Information ◽  
A Value ◽  
Wide Range ◽  
Rate Of Photosynthesis ◽  
Main Factors

Over the past 35 years a great deal has been learned about the mechanisms of photosynthesis, ranging from the ultrafast reactions involved in the initial capture of photons to the slower processes of carbon metabolism. Today our knowledge of photosynthesis and its molecular mechanisms is enormous, so much so that it is difficult for one person to absorb all the information. This is not necessarily a bad thing, since what we have achieved is sufficient information to appreciate the complexity of the “photosynthetic engine” and to identify the main factors that ultimately regulate its efficiency. In this chapter I summarize those areas of photosynthesis research with which I am reasonably familiar and, in so doing, address the question posed by the chapter title. As Blackman (1895a,b) pointed out, the rate of photosynthesis initially rises as the light intensity is increased and then levels off to a plateau. This plot is often referred to as the rate v PFD curve, where PFD stands for Photon Flux Density. Over the years rigorous analyses of the slopes of the rate v PFD curve have been made to obtain a value of the quantum yield (usually expressed as the number of quanta or photons required to produce one molecule of oxygen or to fix one molecule of carbon dioxide). With a few exceptions, the value obtained for a wide range of “non stressed” organisms and plants supplied with excess CO2 is about 9 or a little more (Björkman and Demmig, 1987; Walker, 1992). Bearing in mind that one molecule of oxygen evolved or carbon dioxide fixed is a 4e/4H+ process, then a value of 8 would he consistent with the “Z-scheme” model proposed by Hill and Bendall (1960). In this scheme, each electron is excited twice, first by photosystem two (PSII) and then by photosystem one (PSI). In this way, 8 photons are used to drive 4e/4H+ from water, through PSII and PSI to NADP.

scholarly journals A Chlorophyll Fluorescence-based Biofeedback System to Control Photosynthetic Lighting in Controlled Environment Agriculture

2016 ◽  
Vol 141 (2) ◽  
pp. 169-176 ◽  
Author(s):  
Marc W. van Iersel ◽  
Geoffrey Weaver ◽  
Michael T. Martin ◽  
Rhuanito S. Ferrarezi ◽  
Erico Mattos ◽  
...  
Keyword(s):  
Chlorophyll Fluorescence ◽  
Ipomoea Batatas ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Controlled Environment ◽  
Fluorescence Measurements ◽  
Subsequent Decrease ◽  
Biofeedback System ◽  
Wide Range ◽  
Controlled Environment Agriculture

Photosynthetic lighting is one of the main costs of running controlled environment agriculture facilities. To optimize photosynthetic lighting, it is important to understand how plants use the provided light. When photosynthetic pigments absorb photons, the energy from those photons is used to drive the light reactions of photosynthesis, thermally dissipated, or re-emitted by chlorophyll as fluorescence. Chlorophyll fluorescence measurements can be used to determine the quantum yield of photosystem II (ΦPSII) and nonphotochemical quenching (NPQ), which is indicative of the amount of absorbed light energy that is dissipated as heat. Our objective was to develop and test a biofeedback system that allows for the control of photosynthetic photon flux density (PPFD) based on the physiological performance of the plants. To do so, we used a chlorophyll fluorometer to measure ΦPSII, and used these data and PPFD to calculate the electron transport rate (ETR) through PSII. A datalogger then adjusted the duty cycle of the light-emitting diodes (LEDs) based on the ratio of the measured ETR to a predefined target ETR (ETRT). The biofeedback system was able to maintain ETRs of 70 or 100 µmol·m−2·s−1 over 16-hour periods in experiments conducted with lettuce (Lactuca sativa). With an ETRT of 70 µmol·m−2·s−1, ΦPSII was stable throughout the 16 hour and no appreciable changes in PPFD were needed. At an ETRT of 100 µmol·m−2·s−1, ΦPSII gradually decreased from 0.612 to 0.582. To maintain ETR at 100 µmol·m−2·s−1, PPFD had to be increased from 389 to 409 µmol·m−2·s−1, resulting in a gradual decrease of ΦPSII and an increase in NPQ. The ability of the biofeedback system to achieve a range of different ETRs within a single day was tested using lettuce, sweetpotato (Ipomoea batatas), and pothos (Epipremnum aureum). As the ETRT was gradually increased, the PPFD required to achieve that ETR also increased, whereas ΦPSII decreased. Surprisingly, a subsequent decrease in ETRT, and in the PPFD required to achieve that ETR, resulted in only a small increase in ΦPSII. This indicates that ΦPSII was reduced because of photoinhibition. Our results show that the biofeedback system is able to maintain a wide range of ETRs, while it also is capable of distinguishing between NPQ and photoinhibition as causes for decreases in ΦPSII.

scholarly journals Hydraulic architecture of seedlings and adults of Rhizophora mangle L. in fringe and scrub mangrove

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Diana J. Cisneros-de la Cruz ◽  
Laura Yáñez-Espinosa ◽  
Casandra Reyes-García ◽  
Roberth Us-Santamaría ◽  
José Luis Andrade
Keyword(s):  
Water Potential ◽  
Soil Water Potential ◽  
Biosphere Reserve ◽  
Rhizophora Mangle ◽  
Conduction System ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Hydraulic Architecture ◽  
Mangrove Plant ◽  
Wide Range

Background: Mangrove plant species have distinctive anatomical and physiological responses to cope with a wide range of salinities and inundations. These strategies pertain a safe and efficient water use and transport, essential for survival. Questions: How are the anatomical and physiological attributes of the hydraulic architecture of seedlings and adults of Rhizophora mangle? what are the changes in hydraulic architecture of seedlings and adults of R. mangle in contrasting microenvironments? Studied species: Rhizophora mangle L. (Rhizophoraceae). Study site and dates: Scrub and fringe mangroves in Ria Celestún Biosphere Reserve, during the rainy season of 2013 (July to October). Methods: Hydraulic conductivity and leaf water potential, as well as xylem vessel density, length, transversal and radial diameter, and area were measured for seedlings and adults from both sites. The prevailing environmental conditions (soil water potential, salinity, photon flux density, air temperature and relative humidity) were also characterized. Results: A safer hydraulic conduction system, with narrow and more grouped vessels, was observed in seedlings than in adults of R. mangle in both sites. Adult individuals from the scrub mangrove, in the hyper saline microenvironment, had a safer hydraulic conduction system than adults in the fringe mangrove. Conclusions: The seedling stage of R. mangle showed a safer hydraulic system than adults in both types of mangroves. However, over time this hydraulic conduction system could become more efficient or remain safe depending on the microenvironment in which individuals are growing.

scholarly journals Regeneration of Dracaena surculosa Through Indirect Shoot Organogenesis

HortScience ◽  
2010 ◽  
Vol 45 (8) ◽  
pp. 1250-1254 ◽  
Author(s):  
Juanxu Liu ◽  
Min Deng ◽  
Richard J. Henny ◽  
Jianjun Chen ◽  
Jiahua Xie
Keyword(s):  
Shoot Organogenesis ◽  
Disease Incidence ◽  
Adventitious Shoots ◽  
Leaf Explants ◽  
Basal Medium ◽  
Shoot Formation ◽  
The United States ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Stem Explants

This study established a method of regenerating Dracaena surculosa Lindl. ‘Florida Beauty’ through indirect shoot organogenesis. Bud, leaf, and stem explants were cultured on a Murashige and Skoog basal medium supplemented with N6-(2-isopentyl) adenine (2iP) at 12.3 and 24.6 μM with 3-indoleacetic acid (IAA) at 0, 1.1, and 2.3 μM, respectively, and 2iP at 36.9, 49.2, 61.5, and 73.8 μM with IAA at 1.1 and 2.3 μM, respectively. Calluses were induced from leaf explants but failed to produce adventitious shoots. Calluses were also induced from stem and bud explants cultured on the basal medium containing 12.3 μM 2iP and 2.3 μM IAA, 24.6 μM 2iP or higher with either 1.1 or 2.3 μM IAA. The highest callus induction frequency was 63.2% from stem explants and 69.6% from bud explants when they were cultured on the basal medium supplemented with 49.2 μM 2iP and 2.3 μM IAA. The highest shoot formation frequency was 65.7% from stem-derived callus cultured on the basal medium containing 61.5 μM 2iP and 1.1 μM IAA and 88% from bud-derived callus cultured with 49.2 μM 2iP and 1.1 μM IAA. The highest number of shoots per piece of stem- and bud-derived calluses was 3.8 and 6.7, respectively. Adventitious shoots developed better root systems in the basal medium supplemented with 2.0 μM IAA. Plantlets after transplantation into a soilless substrate grew vigorously in a shaded greenhouse under a maximum photosynthetic photon flux density of 300 μmol·m−2·s−1. Neither disease incidence nor somaclonal variants were observed in the regenerated population. This established method could be used for efficient micropropagation of D. surculosa, and the availability of tissue-cultured liners could reduce the dependency on imported cuttings, which often bring new or invasive pests into the United States.

scholarly journals Development of a novel nannochloropsis strain with enhanced violaxanthin yield for large‐scale production

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Su-Bin Park ◽  
Jin-Ho Yun ◽  
Ae Jin Ryu ◽  
Joohyun Yun ◽  
Ji Won Kim ◽  
...  
Keyword(s):  
Large Scale ◽  
Random Mutagenesis ◽  
Light Condition ◽  
Biomass Productivity ◽  
Scale Production ◽  
Production Potential ◽  
Enhanced Production ◽  
Large Scale Production ◽  
Wide Range ◽  
Normal Light

Abstract Background Nannochloropsis is a marine microalga that has been extensively studied. The major carotenoid produced by this group of microalgae is violaxanthin, which exhibits anti-inflammatory, anti-photoaging, and antiproliferative activities. Therefore, it has a wide range of potential applications. However, large-scale production of this pigment has not been much studied, thereby limiting its industrial application. Results To develop a novel strain producing high amount of violaxanthin, various Nannochloropsis species were isolated from seawater samples and their violaxanthin production potential were compared. Of the strains tested, N. oceanica WS-1 exhibited the highest violaxanthin productivity; to further enhance the violaxanthin yield of WS-1, we performed gamma-ray-mediated random mutagenesis followed by colorimetric screening. As a result, Mutant M1 was selected because of its significant higher violaxanthin content and biomass productivity than WS-1 (5.21 ± 0.33 mg g− 1 and 0.2101 g L− 1 d− 1, respectively). Subsequently, we employed a 10 L-scale bioreactor to confirm the large-scale production potential of M1, and the results indicated a 43.54 % increase in violaxanthin production compared with WS-1. In addition, comparative transcriptomic analysis performed under normal light condition identified possible mechanisms associated with remediating photo-inhibitory damage and other key responses in M1, which seemed to at least partially explain enhanced violaxanthin content and delayed growth. Conclusions Nannochloropsis oceanica mutant (M1) with enhanced violaxanthin content was developed and its physiological characteristics were investigated. In addition, enhanced production of violaxanthin was demonstrated in the large-scale cultivation. Key transcriptomic responses that are seemingly associated with different physiological responses of M1 were elucidated under normal light condition, the details of which would guide ongoing efforts to further maximize the industrial potential of violaxanthin producing strains.

scholarly journals Supplementary Light Source Affects the Growth and Development of Codonopsis lanceolata Seedlings

2018 ◽  
Vol 19 (10) ◽  
pp. 3074 ◽  
Author(s):  
Xiuxia Ren ◽  
Ya Liu ◽  
Hai Jeong ◽  
Byoung Jeong
Keyword(s):  
Light Source ◽  
Soluble Sugar ◽  
Photosynthetic Photon Flux Density ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Root Weight ◽  
Total Biomass ◽  
Codonopsis Lanceolata ◽  
Shoot Weight ◽  
Supplementary Lighting

Codonopsis lanceolata is widely used in traditional medicine and diets. However, there is no optimal protocol for the commercial production of C. lanceolata seedlings. This study was carried out to find the optimum supplementary light source for the production of C. lanceolata seedlings. Seedlings were grown for four weeks in a glasshouse with an average daily light intensity of 490 μmol·m−2·s−1 photosynthetic photon flux density (PPFD) coming from the sun and a 16-h daily supplementary lighting at 120 μmol·m−2·s−1 PPFD from either high-pressure sodium (HPS), metal halide (MH), far-red (FR), white LED (LED-w), or mixed (white: red: blue = 1:2:1) LEDs (LED-mix). The results showed that the greatest total biomass, stem diameter, ratio of shoot weight to shoot length, root biomass, and ratio of root weight to shoot weight were found in seedlings grown under supplementary LED-mix. Meanwhile, the stomatal properties and soluble sugar contents were improved for seedlings in LED-mix. The contents of starch, total phenols, and flavonoids were the greatest for seedlings in LED-w and LED-mix. The expression of photosynthetic proteins and genes in seedlings was also enhanced by LED-mix. Overall, these results suggest that LED-mix is advantageous to the photosynthetic potential and the accumulation of biomass, carbohydrates and secondary metabolites in C. lanceolata.

scholarly journals Timing of Stolon Removal Alters Daughter Plant Production and Quality in the Ever-bearing Strawberry ‘Albion’

HortScience ◽  
2021 ◽  
pp. 1-7
Author(s):  
Xiaonan Shi ◽  
Ricardo Hernández ◽  
Mark Hoffmann
Keyword(s):  
Day Treatment ◽  
Dry Weight ◽  
Photosynthetic Photon Flux Density ◽  
Plant Production ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Total Biomass ◽  
Cultural Methods ◽  
Mother Plants ◽  
The Impact

Commercial strawberry (Fragaria ×ananassa Duch.) plants propagate through the development of stolons (runners) with attached daughter plants. While it is known that temperature and photoperiod affect strawberry propagation, little knowledge exists on whether cultural methods may influence stolon and daughter plant development. The objective of this study was to characterize the impact of three stolon removal treatments on the development of daughter plants in the ever-bearing strawberry ‘Albion’. Treatments included 1) stolon removal every 7 days, nine times total; 2) stolon removal every 21 days, three times total; and 3) one-time stolon removal after 63 days. Strawberry plants were grown in a controlled environment (26 °C, 507 μmol⋅m–2⋅s–1 photosynthetic photon flux density, 14-hour photoperiod) in soilless media and fertilized with a customized nutrient solution. Mother plants in the 63-day treatment produced more daughter plants (102 per plant), than in the 21-day treatment (33 per plant) and the 7-day treatment (16 per plant). In the 63-day treatment, daughter plants and stolons accumulated to 86.6% of the total biomass, to 42.9% in the 7-day treatment and to 60.6% of total biomass in the 21-day treatment. Mother plant organs (including roots, crown, and leaves) had less dry weight in the 63-day treatment compared with the 7-day treatment and 21-day treatment, respectively. Furthermore, the daughter plants produced at the 63-day treatment had smaller crown diameters (0.65 cm) and less dry weight (0.51 g) and a higher number of fully expanded leaves (2.9) and visible roots (13.4) compared with the 21-day treatment and the 7-day treatment. The results of this study show daughter plant production of strawberry plants declines significantly with shorter stolon removal intervals, indicating the need to adjust stolon removal in strawberry nurseries for optimal daughter plant production.

Automatic thresholding for digital hemispherical photography

2004 ◽  
Vol 34 (11) ◽  
pp. 2208-2216 ◽  
Author(s):  
Megumi Ishida
Keyword(s):  
Coniferous Forest ◽  
Digital Camera ◽  
Photosynthetic Photon Flux Density ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Automatic Thresholding ◽  
Broad Leaved Forest ◽  
Wide Range ◽  
Hemispherical Photographs ◽  
Thresholding Algorithm

This paper proposes an automatic thresholding method for the discrimination of sky and canopy elements in color hemispherical photographs taken with a digital camera (Nikon Coolpix 950). The exposures for photography were principally determined on the basis of zenith luminance. DIFphoto, which is diffuse transmittance calculated from the hemispherical photographs, was related to DIFsensor, which is diffuse transmittance measured directly with a photosynthetic photon flux density sensor. First, the thresholds for calculation of DIFphoto were manually assessed in the photographs to obtain the best match with DIFsensor. At the lower pixel-value level in the pixel histograms from the photographs, L-shaped curves were always recognized, and the threshold occurred at the point with the maximum curvature. Second, an automatic thresholding algorithm, taking into account the position of the thresholds, was computerized. Third, the relationships between DIFphoto and DIFsensor were field-tested across a wide range of light conditions. The method was effective in a planted coniferous forest and a natural broad-leaved forest and under overcast, twilit, and sunny sky conditions. The coefficients of determination between DIFsensor and DIFphoto were greater than 0.99. However, DIFphoto taken with Auto-Exposure was overestimated under dense canopy.

scholarly journals Effect of Supplementary Lighting Duration on Growth and Activity of Antioxidant Enzymes in Grafted Watermelon Seedlings

Agronomy ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 337 ◽  
Author(s):  
Hao Wei ◽  
Mengzhao Wang ◽  
Byoung Ryong Jeong
Keyword(s):  
Light Intensity ◽  
Growth And Development ◽  
Weight Ratio ◽  
Dry Weight ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Antioxidant Enzyme Activities ◽  
Total Biomass ◽  
Supplementary Lighting

Insufficient exposure to light in the winter may result in a longer production periods and lower quality of seedlings in greenhouses for plug growers. Supplementary artificial lighting to plug seedlings may be one solution to this problem. The objective of this study was to assess the effects of the duration of the supplementary light on the growth and development of two watermelon cultivars, ‘Speed’ and ‘Sambok Honey’ grafted onto ‘RS-Dongjanggun’ bottle gourd rootstocks (Lagenaria siceraria Stanld). Seedlings were grown for 10 days in a glasshouse with an average daily natural light intensity of 340 μmol·m−2·s−1 photosynthetic photon flux density (PPFD) and daily supplementary lighting of 8, 12 or 16 h from mixed LEDs (W1R2B1, chip ratio of white:red:blue = 1:2:1) at a light intensity of 100 μmol·m−2·s−1 PPFD, a group without supplementary light was set as the control (CK). The culture environment in a glasshouse had 25/15 °C day/night temperatures, an 85 ± 5% relative humidity, and a natural photoperiod of 8 h. The results showed that all the growth and development parameters of seedlings grown with supplementary light were significantly greater than those without supplementary light (CK). The 12 and 16 h supplementary light resulted in greater growth and development parameters than the 8 h supplementary light did. The same trend was also found with the indexes that reflect the quality of the seedlings, such as the dry weight ratio of the shoot and root, total biomass, dry weight to height ratio of scions, and specific leaf weight. The 12 h and 16 h light supplements resulted in greater Dickson’s quality indexes compared to the 8 h supplementary light, and the 12 h supplementary light showed the greatest use efficiency of the supplementary light. 16 h of daily supplementary light significantly increased the H2O2 content and the antioxidant enzyme activities in seedlings compared to the other treatments. This indicated that 16 h of supplementary light led to certain stresses in watermelon seedlings. In conclusion, considering the energy consumption, 12 h of supplementary light was the most efficient in improving the quality of the two cultivars of grafted watermelon plug seedlings.

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