•Studies on green light effects in tall, canopy forming crops (e.g. tomato) are rare.•Partially replacing a red:blue spectrum by green increased biomass by up to 6.5%.•Green tended to increase leaf ...biomass, specific leaf area, stem biomass and length.•In the middle of the canopy, carotenoid concentrations increased under green light.•Photosynthetic efficiency per waveband cannot explain effects on growth under several wavebands.
Effects of green light on plant growth are relatively understudied, and published results are contradictory. Although per unit leaf area, green light drives photosynthesis less efficiently than does red light, on a whole-plant level green light may increase growth due to changes in vertical light distribution, leaf light acclimation and canopy architecture. As most studies were conducted on small plants with compact stems, positive effects may have remained unnoticed. In a greenhouse experiment, a tomato (Solanum lycopersicum) crop was exposed to 7, 20 or 39% of green light in a background of narrow bandwidth red and blue light, as well as sunlight, for 76 days. The intensity supplied by lamps (171 μmol m−2 s−1) and the red:blue ratio were similar between treatments. Adding green light (+32%) to the spectrum significantly and linearly increased plant biomass and yield (+6.5%). With increasing green light percentage, there were tendencies for linear increases in leaf biomass (P = 0.06), specific leaf area (P = 0.09), stem biomass (P = 0.07), stem length (P = 0.05) and number of internodes (P = 0.05). In the top and middle leaf layers of the canopy, net photosynthesis rate, stomatal conductance and leaf thickness were unaffected by the treatment while in leaves in the middle leaf layer, chlorophyll a:b ratio and carotenoid concentrations increased with the percentage of green light. This study shows that partial replacement of red by green light increases growth of plants in dense canopies and suggests that the combined effects of a light spectrum on plant growth are more than the sum of wavelength effects on photosynthetic efficiency.
Light quantity (intensity and photoperiod) and quality (spectral composition) affect plant growth and physiology and interact with other environmental parameters and cultivation factors in ...determining the plant behaviour. More than providing the energy for photosynthesis, light also dictates specific signals which regulate plant development, shaping and metabolism, in the complex phenomenon of photomorphogenesis, driven by light colours. These are perceived even at very low intensity by five classes of specific photoreceptors, which have been characterized in their biochemical features and physiological roles. Knowledge about plant photomorphogenesis increased dramatically during the last years, also thanks the diffusion of light-emitting diodes (LEDs), which offer several advantages compared to the conventional light sources, such as the possibility to tailor the light spectrum and to regulate the light intensity, depending on the specific requirements of the different crops and development stages. This knowledge could be profitably applied in greenhouse horticulture to improve production schedules and crop yield and quality. This article presents a brief overview on the effects of light spectrum of artificial lighting on plant growth and photomorphogenesis in vegetable and ornamental crops, and on the state of the art of the research on LEDs in greenhouse horticulture. Particularly, we analysed these effects by approaching, when possible, each single-light waveband, as most of the review works available in the literature considers the influence of combined spectra.
Rapid technology development in controlled environment (CE) plant production has been applied to a large variety of plants. In recent years, strawberries have become a popular fruit for CE production ...because of their high economic and nutritional values. With the widespread use of light-emitting diode (LED) technology in the produce industry, growers can manipulate strawberry growth and development by providing specific light spectra. Manipulating light intensity and spectral composition can modify strawberry secondary metabolism and highly impact fruit quality and antioxidant properties. While the impact of visible light on secondary metabolite profiles for other greenhouse crops is well documented, more insight into the impact of different light spectra, from UV radiation to the visible light spectrum, on strawberry plants is required. This will allow growers to maximize yield and rapidly adapt to consumer preferences. In this review, a compilation of studies investigating the effect of light properties on strawberry fruit flavonoids is provided, and a comparative analysis of how light spectra influences strawberry's photobiology and secondary metabolism is presented. The effects of pre-harvest and post-harvest light treatments with UV radiation and visible light are considered. Future studies and implications for LED lighting configurations in strawberry fruit production for researchers and growers are discussed.
Red and blue light are traditionally believed to have a higher quantum yield of CO
assimilation (
, moles of CO
assimilated per mole of photons) than green light, because green light is absorbed less ...efficiently. However, because of its lower absorptance, green light can penetrate deeper and excite chlorophyll deeper in leaves. We hypothesized that, at high photosynthetic photon flux density (
), green light may achieve higher
and net CO
assimilation rate (
) than red or blue light, because of its more uniform absorption throughtout leaves. To test the interactive effects of
and light spectrum on photosynthesis, we measured leaf
of "Green Tower" lettuce (
) under red, blue, and green light, and combinations of those at
s from 30 to 1,300 μmol⋅m
⋅s
. The electron transport rates (
) and the maximum Rubisco carboxylation rate (
) at low (200 μmol⋅m
⋅s
) and high
(1,000 μmol⋅m
⋅s
) were estimated from photosynthetic CO
response curves. Both
(maximum
on incident
basis) and
at low
were higher under red light than under blue and green light. Factoring in light absorption,
(the maximum
on absorbed
basis) under green and red light were both higher than under blue light, indicating that the low
under green light was due to lower absorptance, while absorbed blue photons were used inherently least efficiently. At high
, the
gross CO
assimilation (
)/incident
and
under red and green light were similar, and higher than under blue light, confirming our hypothesis.
may not limit photosynthesis at a
of 200 μmol m
s
and was largely unaffected by light spectrum at 1,000 μmol⋅m
⋅s
.
and
under different spectra were positively correlated, suggesting that the interactive effect between light spectrum and
on photosynthesis was due to effects on
. No interaction between the three colors of light was detected. In summary, at low
, green light had the lowest photosynthetic efficiency because of its low absorptance. Contrary, at high
,
under green light was among the highest, likely resulting from more uniform distribution of green light in leaves.
Endogenous signals in response to exogenous factors determine the senescence of flowers. Interactions among phytohormones especially abscisic acid (ABA) and ethylene are the major determinant of the ...senescence. In the present study, complex expression patterns of the genes related to ABA and ethylene as endogenous signals were investigated on cut carnations (Dianthus caryophyllus L.) that were exposed to different light spectra. Expression of ethylene biosynthetic (DcACS and DcACO), and signaling (DcETR and DcEin2) genes and also genes involved in ABA biosynthesis (DcZEP1 and DcNCED1), transport (DcABCG25 and DcABCG40) and catabolism (DcCYP707A1) were evaluated in petals of carnations exposed to three light spectra white, blue and red. Lowest relative membrane permeability (RMP) was detected in flowers that exposed to Blue light (BLFs), as a consequence, the longest vase life was found in BLFs. The Red and White lights markedly accelerated flower senescence and increased expression of DcACS and DcACO on day 6 and 10 of vase life assessment respectively; while Blue light inhibited the expression of ethylene biosynthetic genes. Expression of the genes involved in the production and transport of ABA and in signal transduction of ethylene was elevated during vase life of flowers irrespective of exposure to different light spectra. In conclusion, Blue light can be an effective environmental factor to extend the vase life of carnation flowers by delaying the petal senescence through down-regulation of ethylene biosynthetic genes and up-regulation of ABA biosynthetic genes.
•Blue light postpones petal senescence and improves vase life of carnation flowers.•Blue light suppresses expression of ethylene biosynthetic genes in cut carnations.•Blue light stimulates expression of ABA biosynthetic genes in cut carnations.•Stomatal opening and increased in water loss occurs due to blue light-exposure.
Potato (Solanum tuberosum
L
.) is a significant and valuable crop for the economy of many countries. It provides people nutrition and national food security. To obtain healthy potato planting ...material, propagation in vitro culture is carried out. The problem of increasing the propagation efficiency at this stage is very relevant and can be solved by optimizing the lighting parameters, including the spectral composition of the emitter. The review of published works mainly over the last 20 years concerning the study of the effect of LED lighting of different spectral composition and power on regenerated potato plants, grown in vitro, is given in this paper. Morphometric and physiological parameters of potato plants are given, which can be influenced by changing the spectral composition of illumination. Data on lighting recommendations for different varieties of potato are given. This review may be useful for organizations involved in potato micropropagation, as well as for research teams developing technologies for optimal potato cultivation.
Indonesia is the largest exporter of edible bird’s nest (EBN) to China, involving many EBN farmers from various regions in Indonesia. Therefore, a portable device is needed to rapidly and accurately ...measure the required quality of SBW to avoid rejection by Chinese buyers, which could result in significant losses. Consequently, for this purpose, an electronic instrument has been developed. smartAgro-Spectral is a microcontroller-based electronic instrument that measures nitrite content in edible bird’s nest (EBN) using linear regression method in machine learning calculations. This instrument can measure nitrite content based on the intensity of colors produced by EBN products. The coloring process is carried out by mixing EBW powder with Sulphanilamide solution and N-(1-naphthyl) Ethylenediamine Dihydrochloride (NED) solution. The concentration of EBN solution is normalized to values between 0.2 ppm and 0.7 ppm. The measurement process is carried out by emitting 18 waves of the light spectrum. The intensity of the 18 wavelengths of the measured light spectrum was selected based on the strong correlation between the intensity of the light spectrum and the value of nitrite content in the EBN product. The measurement results show that the intensity of the light spectrum that has a strong linear correlation is at wavelengths of 460 nm, 485 nm, 510 nm, 535 nm, and 610 nm. So, smartAgro-Spectral electronic instruments can be realized based on the intensity relationship of each wavelength through multiple linear regression analysis, and are able to linearly measure nitrite content in EBW products with a precision level of 99.85% and an accuracy rate of 99.85%.
Light is one of the main signals detected by plants that influence plant growth, development, and function. The light features that influence plants are the photoperiod, light intensity, and spectral ...composition. Manipulating light intensity and spectrum to obtain better plant growth and quality has become a popular research object in recent years. Here we describe the usage of the spectrometer Lighting Passport Pro to determine the impact of light intensity and share of individual waves in its spectrum in environment-controlled plant production systems on the growth, development, and soluble carbohydrate and phenolic synthesis of common buckwheat.
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