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

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.

Download Full-text

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.

Download Full-text

Effect of Supplementary Light Intensity on Quality of Grafted Tomato Seedlings and Expression of Two Photosynthetic Genes and Proteins

Agronomy ◽

10.3390/agronomy9060339 ◽

2019 ◽

Vol 9 (6) ◽

pp. 339 ◽

Cited By ~ 4

Author(s):

Hao Wei ◽

Jin Zhao ◽

Jiangtao Hu ◽

Byoung Ryong Jeong

Keyword(s):

Light Intensity ◽

Dry Weight ◽

Photosynthetic Photon Flux Density ◽

Photon Flux ◽

Photon Flux Density ◽

Natural Lighting ◽

Tomato Seedlings ◽

Photosynthetic Genes ◽

Supplemental Lighting

Lower quality and longer production periods of grafted seedlings, especially grafted plug seedlings of fruit vegetables, may result from insufficient amounts of light, particularly in rainy seasons and winter. Supplemental artificial lighting may be a feasible solution to such problems. This study was conducted to evaluate light intensity’s influence on the quality of grafted tomato seedlings, ‘Super Sunload’ and ‘Super Dotaerang’ were grafted onto the ‘B-Blocking’ rootstock. To improve their quality, grafted seedlings were moved to a glasshouse and grown for 10 days. The glasshouse had a combination of natural lighting from the sun and supplemental lighting from LEDs (W1R2B2) for 16 h/day. Light intensity of natural lighting was 490 μmol·m−2·s−1 photosynthetic photon flux density (PPFD) and that of supplemental lighting was 50, 100, or 150 μmol·m−2·s−1 PPFD. The culture environment had 30/25 °C day/night temperatures, 70% ± 5% relative humidity (RH), and a natural photoperiod of 14 h as well. Compared with quality of seedlings in supplemental lighting of 50 μmol·m−2·s−1 PPFD, that of seedlings in supplement lighting of 100 or 150 μmol·m−2·s−1 PPFD improved significantly. With increasing light intensity, diameter, fresh weight, and dry weight, which were used to measure shoot growth, greatly improved. Leaf area, leaf thickness, and root biomass were also greater. However, for quality of seedlings, no significant differences were discovered between supplement lighting of 100 μmol·m−2·s−1 PPFD and supplement lighting of 150 μmol·m−2·s−1 PPFD. Expressions of PsaA and PsbA (two photosynthetic genes) as well as the corresponding proteins increased significantly in supplement lightning of 100 and 150 μmol·m−2·s−1 PPFD, especially in 100 μmol·m−2·s−1 PPFD. Overall, considering quality and expressions of two photosynthetic genes and proteins, supplemental light of 100 μmol·m−2·s−1 PPFD (W1R2B1) would be the best choice to cultivate grafted tomato seedlings.

Download Full-text

Optimization of Artificial Light for Spinach Growth in Plant Factory Based on Orthogonal Test

Plants ◽

10.3390/plants9040490 ◽

2020 ◽

Vol 9 (4) ◽

pp. 490

Author(s):

Tengyue Zou ◽

Chuanhui Huang ◽

Pengfei Wu ◽

Long Ge ◽

Yong Xu

Keyword(s):

Light Intensity ◽

Sugar Content ◽

Soluble Sugar ◽

Dry Weight ◽

Photosynthetic Photon Flux Density ◽

Influential Factor ◽

Photon Flux ◽

Photon Flux Density ◽

Scoring Method ◽

Light Mode

Artificial LED source provides the possibility to regulate the lighting environment in plant factorys that use limited space to plant, aiming at high throughput and good quality. However, different parameters of light intensity, quality, and photoperiod will influence the growth and accumulation of bio-compounds in plants. In order to find the optimal setting of LED light for spinach planting, four group experiments were designed using the orthogonal testing method. According to the experimental results, for growth indexes including fresh weight, dry weight, root length and so on, photoperiod is the most influential factor, light intensity is the second, and light quality is the least. The best light mode (R:B = 4:1, photosynthetic photon flux density (PPFD) = 100 μmol∙m−2∙s−1 and 13/11 h) among all eight possible combinations in the range was also determined. Furthermore, for quality indexes, including the soluble sugar content, protein content and so on, a new scoring method was introduced to make a comprehensive score for evaluating. Then, the light combination (R:B = 4:1, PPFD = 150 μmol∙m−2∙s−1 and 9/15 h) in the range was found as the optimal scheme for spinach quality under those parameters. As there is trade-off between the optimal light parameters for growth and quality, it is necessary to achieve a balance between yield and quality of the plant during production. If farmers want to harvest spinach with larger leaf area and higher yield, they need to pay attention to the adjustment of the photoperiod and use a lower light intensity and a longer lighting time. If they do not mind the yield of the vegetable but want to improve the taste and nutrition of spinach products, they should pay more attention to the light intensity and use a higher light intensity and a shorter lighting time.

Download Full-text

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.

Download Full-text

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.

Download Full-text

The value of red light at night for increasing basil yield

Canadian Journal of Plant Science ◽

10.1139/cjps-2017-0343 ◽

2018 ◽

Vol 98 (6) ◽

pp. 1321-1330

Author(s):

Jaimin S. Patel ◽

Leora Radetsky ◽

Mark S. Rea

Keyword(s):

Plant Height ◽

Red Light ◽

Leaf Size ◽

Cost Effective ◽

Dry Weight ◽

Photosynthetic Photon Flux Density ◽

Photon Flux ◽

Photon Flux Density ◽

Light At Night ◽

Sweet Basil

Sweet basil (Ocimum basilicum L.) is primarily used for culinary purposes, but it is also used in the fragrance and medicinal industries. In the last few years, global sweet basil production has been significantly impacted by downy mildew caused by Peronospora belbahrii Thines. Nighttime exposure to red light has been shown to inhibit sporulation of P. belbahrii. The objective of this study was to determine if nighttime exposure to red light from light-emitting diodes (λmax = 625 nm) could increase plant growth (plant height and leaf size) and yield (number and weight of leaves) in basil plants. In two sets of greenhouse experiments, red light was applied at a photosynthetic photon flux density of 60 μmol m−2 s−1 during the otherwise dark night for 10 h (from 2000 to 0600). The results demonstrate that exposure to red light at night can increase the number of basil leaves per plant, plant height, leaf size (length and width), and leaf fresh and dry weight compared with plants in darkness at night. The addition of incremental red light at night has the potential to be cost-effective for fresh organic basil production in controlled environments.

Download Full-text

Optimal LED Wavelength Composition for the Production of High-Quality Watermelon and Interspecific Squash Seedlings Used for Grafting

Agronomy ◽

10.3390/agronomy9120870 ◽

2019 ◽

Vol 9 (12) ◽

pp. 870 ◽

Cited By ~ 1

Author(s):

Filippos Bantis ◽

Athanasios Koukounaras ◽

Anastasios S. Siomos ◽

Kalliopi Radoglou ◽

Christodoulos Dangitsis

Keyword(s):

Blue Emission ◽

Dry Weight ◽

Photosynthetic Photon Flux Density ◽

Stem Diameter ◽

Photon Flux ◽

Photon Flux Density ◽

Light Sources ◽

High Quality ◽

Light Emitting ◽

Shoot Dry Weight

Watermelon is cultivated worldwide and is mainly grafted onto interspecific squash rootstocks. Light-emitting diodes (LEDs) can be implemented as light sources during indoor production of both species and their spectral quality is of great importance. The objective of the present study was to determine the optimal emission of LEDs with wide wavelength for the production of watermelon and interspecific squash seedlings in a growth chamber. Conditions were set at 22/20 °C temperature (day/night), 16 h photoperiod, and 85 ± 5 μmol m−2 s−1 photosynthetic photon flux density. Illumination was provided by fluorescent (FL, T0) lamps or four LEDs (T1, T2, T3, and T4) emitting varying wide spectra. Watermelon seedlings had greater shoot length, stem diameter, cotyledon area, shoot dry weight-to-length (DW/L) ratio, and Dickson’s quality index (DQI) under T1 and T3, while leaf area and shoot dry weight (DW) had higher values under T1. Interspecific squash seedlings had greater stem diameter, and shoot and root DW under T1 and T3, while leaf and cotyledon areas were favored under T1. In both species, T0 showed inferior development. It could be concluded that a light source with high red emission, relatively low blue emission, and a red:far-red ratio of about 3 units seems ideal for the production of high-quality watermelon (scion) and interspecific squash (rootstock) seedlings.

Download Full-text

Effects of CO2 enrichment on growth of Liquidambarstyraciflua and Pinustaeda seedlings under different irradiance levels

Canadian Journal of Forest Research ◽

10.1139/x84-063 ◽

1984 ◽

Vol 14 (3) ◽

pp. 343-350 ◽

Cited By ~ 83

Author(s):

Leslie C. Tolley ◽

B. R. Strain

Keyword(s):

Loblolly Pine ◽

Atmospheric Carbon Dioxide ◽

Co2 Enrichment ◽

Dry Weight ◽

Photosynthetic Photon Flux Density ◽

High Irradiance ◽

Photon Flux ◽

Photon Flux Density ◽

Dry Matter Accumulation ◽

Pine Seedlings

Mathematical growth analysis techniques were used to assess the effects of atmospheric carbon dioxide enrichment on growth and biomass partitioning of Liquidambarstyraciflua L. (sweetgum) and Pinustaeda L. (loblolly pine) seedlings. Plants were grown from seed under high (1000 μmol•m−2•s−1) and low (250 μmol•m−2•s−1) photosynthetic photon flux density at CO2 concentrations of 350, 675, and 1000 μL•L−1 for 84 or 112–113 days. Elevated atmospheric CO2 concentration significantly increased height, leaf area, basal stem diameter, and total dry weight of sweetgum seedlings grown under high irradiance and to a lesser extent under low irradiance. Increases in dry matter accumulation were associated with early CO2 enhancement of net assimilation rate, but increases in amount of leaf surface area contributed more towards maintenance of larger size as seedlings aged. For sweetgum seedlings in particular, reduction of growth by low irradiance under normal atmospheric CO2 was compensated for by growing plants with elevated CO2. In contrast, elevated CO2 concentration produced no significant increase in growth of loblolly pine seedlings.

Download Full-text

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.

Download Full-text

Supplementary LED Interlighting Improves Yield and Precocity of Greenhouse Tomatoes in the Mediterranean

Agronomy ◽

10.3390/agronomy10071002 ◽

2020 ◽

Vol 10 (7) ◽

pp. 1002 ◽

Cited By ~ 5

Author(s):

Ivan Paucek ◽

Giuseppina Pennisi ◽

Alessandro Pistillo ◽

Elisa Appolloni ◽

Andrea Crepaldi ◽

...

Keyword(s):

Growth Yield ◽

Photosynthetic Photon Flux Density ◽

Fruit Weight ◽

Soluble Solids ◽

Control Treatment ◽

Photon Flux ◽

Photon Flux Density ◽

Vegetative Development ◽

Greenhouse Production ◽

The Mediterranean

In Northern Europe, the use of light–emitting diodes (LEDs) is widely adopted in protected horticulture, enabling to enhance plant growth by ensuring needed radiative fluxes throughout seasons. Contrarily, the use of artificial lighting in Mediterranean greenhouse still finds limited applications. In this study, the effects of supplemental LED interlighting on vegetative development, fruit growth, yield, and fruit quality of high-wire tomato plants (Solanum lycopersicum L. cv. ‘Siranzo’) during spring and summer season were addressed in a hydroponic greenhouse in Italy. Plants were either grown under natural solar radiation (control), or by adding supplemental LED interlighting. LED treatment featured red (R) and blue (B) light (RB ratio of 3) and a photosynthetic photon flux density of 170 µmol m−2 s−1 for 16 h d−1. Supplemental LED interlighting enhanced yield as a result of increased fruit weight and dimension. While no effects on soluble solids content and fruit color at harvesting were observed, supplemental LED interlighting accelerated ripening by one week in spring and two weeks in summer and this also resulted in increased cumulated productivity (+16%) as compared to control treatment. Overall, supplemental LED interlighting can represent a feasible technology for tomato greenhouse production also in the Mediterranean region.

Download Full-text