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

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.

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

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.

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

Agronomy ◽  
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.

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

Agronomy ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 339 ◽  
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.

scholarly journals Manipulating Light Intensity and Fall Fertilization to Influence Photosynthesis and Freeze Resistance of Azaleas

HortScience ◽  
2006 ◽  
Vol 41 (4) ◽  
pp. 977A-977
Author(s):  
Frank Henning ◽  
Timothy J. Smalley ◽  
Orville M. Lindstrom ◽  
John M. Ruter
Keyword(s):  
Light Intensity ◽  
Fertilizer Application ◽  
High Irradiance ◽  
Fertilizer Treatment ◽  
Freeze Resistance ◽  
Main Plot ◽  
Plant Stem ◽  
Maximum Quantum Efficiency ◽  
Plot Experiment ◽  
Quantum Efficiency Of Psii

On 1 May 2004, a 4 × 2 split-plot experiment was initiated in Athens, Ga., on Rhododendron ×kurume `Pink Pearl'. The four main-plot treatments were low irradiance, low irradiance May–October, low irradiance November–May, and high irradiance (high and low correspond to average daily PPF of 23.6 and 10.4 mol·m-2·d-1). The two subplot fall fertigation treatments were 75 mg·L-1 of nitrogen (N) and 125 mg·L-1 N. Plant stem tissue was harvested monthly from November to March, and analyzed for freeze resistance (LT50). Maximum quantum efficiency of PSII (Fv/Fm) was analyzed monthly with a Mini-pam photosynthesis yield analyzer. No interactions existed between fertilizer application and light intensity and the 125 mg·L-1 N fertilizer treatment reduced freeze resistance of azalea stems throughout the study. Fall fertilization had no effect on fluorescence and no interactions existed between fertilizer and irradiance treatments. In November, plants that received low irradiance May–October were less freeze-resistant than plants from the high-irradiance treatment. However, in January, plants that received low irradiance throughout the study were more freeze-resistant than plants that received the high-irradiance treatment. In November, Fv/Fm was higher in the low irradiance and low irradiance November–May treatments. In February and March, Fv/Fm was lower in the low May–November treatment that received low irradiance during summer than the low November–May treatment that received low winter irradiance. The use of shade to reduce irradiance may delay the acquisition of freeze resistance in fall. However, shade may reduce photosystem damage and increase a plants ability to acquire and maintain greater freeze resistance.

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.

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

Plants ◽  
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.

scholarly journals The Effect of Low Light Intensity and Temperature on Growth of Schefflera arboricola in Interior Landscapes

HortScience ◽  
2007 ◽  
Vol 42 (1) ◽  
pp. 65-67 ◽  
Author(s):  
Astrid Kubatsch ◽  
Heiner Grüneberg ◽  
Christian Ulrichs
Keyword(s):  
Light Intensity ◽  
Chlorophyll Content ◽  
Dry Weight ◽  
Leaf Thickness ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Low Light ◽  
Light Intensities ◽  
Temperature Regimes ◽  
Schefflera Arboricola

Schefflera arboricola was held in light- and temperature-controlled chambers for 6 months under three light intensities of 10 μmol·m–2·s–1, 20 μmol·m–2·s–1, and 80 μmol·m–2·s–1 measured as photon flux density (PFD). Plants also received three temperature regimes: 15 °C, 20 °C, and 25 °C. Reduced light intensity significantly decreased fresh and dry weight and increased chlorophyll content, but did not affect leaf thickness and palisade and spongy mesophyll parenchyma. High temperatures reduced fresh weight and significantly increased chlorophyll content and leaf thickness. The authors conclude that reduced photosynthetic energy flow at low light intensities (10 μmol·m–2·s–1, 20 μmol·m–2·s–1) could not be buffered by a downregulation of energy-consuming processes. Therefore the life span and quality of S. arboricola is reduced at such PFD values, especially at higher temperatures. Plants lose their marketability within 6 months.

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

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.

scholarly journals Growth and Yield Response of Rodent Tuber (Typhonium flagelliforme (Lodd.) Blume) under Different Light Intensities and Concentrations of Paclobutrazol

2016 ◽  
Vol 1 (3) ◽  
pp. 29-35
Author(s):  
Noorwitri Utami ◽  
Lukita Devy ◽  
Arief Arianto
Keyword(s):  
Light Intensity ◽  
Concentration Level ◽  
Dry Weight ◽  
Leaf Length ◽  
Growth And Yield ◽  
Yield Response ◽  
Full Sunlight ◽  
Anticancer Treatment ◽  
Main Plot ◽  
Number Of Leaves

Rodent tuber (Typhonium flagelliforme (Lodd) Blume) is one of the medicinal plants used for anticancer treatment, but the information on the cultivation of the plant is limited. The objectives of this research was to study the effect of light intensity and concentration level of paclobutrazol on growth and yield of rodent tuber. This research was conducted at Puspiptek Serpong, Tangerang Selatan, Indonesia. This experiment arranged in a split plot design with three replications. The main plot is light intensity (35, 55, and 100%). The sub plot is concentration level of paclobutrazol (0, 50, 100, and 150 ppm). Paclobutrazol applied as soil drench at one month after planting. In each application 500 ml solution was used. Variables observed consisted of plant height, number of leaves, leaf length, leaf width, leaf and tuber fresh weight; and leaf and tuber dry weight. Data were analyzed using analysis of variance and Duncan Multiple Range test at 5%. The result showed that interaction between light intensity and paclobutrazol affected the whole observed variable. Dry weight of tuber under 35% light intensity was lower than those in other light intensity for all treatments of paclobutrazol. Full sunlight intensity showed better dry weight in all treatments of paclobutrazol. However the dry weight decreasing significantly at 150 ppm paclobutrazol, but still higher than those in 35% light intensity. Therefore, rodent tuber is better cultivated under full sunlight and 55% light intensity with 100 ppm paclobutrazol.

The value of red light at night for increasing basil yield

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.

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