Impact of a Variable Light Intensity at a Constant Light Integral: Effects on Biomass and Production of Secondary Metabolites by Hypericum Perforatum

Brechner, Melissa L; Albright, L. D.; Weston, Leslie A.

doi:10.17660/actahortic.2007.756.23

Cited by 4 publications

(3 citation statements)

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“…1). However, further investigations revealed that this correlation differs for dissimilar plant species (Prince 1991, Brechner et al 2007 as was also confirmed by the authors' own experiments. In their investigations, plant species characterized by the lowest light requirements (garden rocket and garden chervil) were found to exhibit the highest fresh mass increments in relation to the absorbed photons.…”

Section: Resultssupporting

confidence: 75%

Effect of Light Conditions and Temperature on Fresh Yield of Some Spice Plants Grown in Containers

Frąszczak

Knaflewski

2009

Journal of Fruit and Ornamental Plant Research

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SummaryThe aim of this work was to study the effect of quantity of light, length of day and temperature on yield of five species of spice plants. Another purpose of the study was to determine the correlation between the climatic factors mentioned above and to find the optimum coefficient of growth for the individual species. Three levels of temperature during the day were determined: 15, 20 and 25ºC (at night the temperature was by 5ºC lower). Two daily light integrals (2.9 and 3.8 mol·m -2 ·d -1 ) and three levels of photoperiod (12, 14 and 16-h) were chosen.Photon flux and temperature had the greatest influence on yield. A higher yield of fresh mass was obtained for all species in the condition of 3,8 mol·mYield depended linearly on amount of photon absorbed by plants in the growth time. Dry weight was directly connected with RRT (the ratio of radiant energy to thermal energy) and increased linearly as RRT increased.

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Section: Resultssupporting

confidence: 75%

Effect of Light Conditions and Temperature on Fresh Yield of Some Spice Plants Grown in Containers

Frąszczak

Knaflewski

2009

Journal of Fruit and Ornamental Plant Research

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“…However, once nutrient concentration and temperature, respectively, increased above 50% and 23 °C, there was a gradual decline in the response. Brechner et al reported that in controlled environments, hyperforin concentration in St John’s wort was consistently higher at a light intensity of 90 μmol m −2 s −1 PPFD, versus light intensities of 160 or 340 μmol m −2 s −1 PPFD [ 40 ]. Temperature is an important abiotic factor that greatly influences the growth, yield, and quality of crop plants, and the morphology of seedlings.…”

Section: Resultsmentioning

confidence: 99%

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

et al. 2020

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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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“…Light is an essential environmental factor affecting plant morphogenesis and physiological metabolism, which regulates plant growth and development due to three main aspects: light quality, light intensity, and photoperiod [6]. Daily light integral (DLI) is the product of the combination of light intensity and photoperiod and can be used as a light variable for plant growth instead of light intensity or photoperiod alone [7,8]. The four light aspects can be precisely controlled inside plant factories for crop production [9,10].…”

Section: Introductionmentioning

confidence: 99%

Response of Flavor Substances in Tomato Fruit to Light Spectrum and Daily Light Integral

Fan,

Lu,

et al. 2023

Plants

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Light-emitting diodes (LEDs) have been widely used as light sources for plant production in plant factories with artificial lighting (PFALs), and light spectrum and light amount have great impacts on plant growth and development. With the expansion of the product list of PFALs, tomato production in PFALs has received attention, but studies on fruit quality influenced by artificial light are lacking. In this study, precisely modulated LED light sources based on white light combined with additional red, blue, and green lights were used to investigate the effects of light spectrum and daily light integral (DLI) on the main quality indicators and flavor substances of “Micro-Tom” tomato fruits. The highest sugar–acid ratio was obtained under the white light with addition of red light with high DLI and blue light with low DLI. The contents of β-carotene, lycopene, and lutein were significantly increased by higher DLI conditions except for under the blue light treatment, and the cross-interactions between the light spectrum and DLI were observed. The accumulation of the main flavor substances in tomato fruits was decreased by addition of green light with a high DLI and red light with a low DLI; notably, the percentage of 2-isobutylthiazole, which is associated with fresh tomato aroma, was decreased by green light. This study provides insights for improving tomato fruit quality and flavor by regulating light conditions in PFALs.

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Impact of a Variable Light Intensity at a Constant Light Integral: Effects on Biomass and Production of Secondary Metabolites by Hypericum Perforatum

Cited by 4 publications

References 0 publications

Effect of Light Conditions and Temperature on Fresh Yield of Some Spice Plants Grown in Containers

Effect of Light Conditions and Temperature on Fresh Yield of Some Spice Plants Grown in Containers

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

Response of Flavor Substances in Tomato Fruit to Light Spectrum and Daily Light Integral

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