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Commonly used image fusion techniques generally produce good results for images obtained from the same sensor, with a standard ratio of spatial resolution (1:4). However, an atypical high ratio of resolution reduces the effectiveness of fusion methods resulting in a decrease in the spectral or spatial quality of the sharpened image. An important issue is the development of a method that allows for maintaining simultaneous high spatial and spectral quality. The authors propose to strengthen the pan-sharpening methods through prior modification of the panchromatic image. Local statistics of the differences between the original panchromatic image and the intensity of the multispectral image are used to detect spatial details. The Euler’s number and the distance of each pixel from the nearest pixel classified as a spatial detail determine the weight of the information collected from each integrated image. The research was carried out for several pan-sharpening methods and for data sets with different levels of spectral matching. The proposed solution allows for a greater improvement in the quality of spectral fusion, while being able to identify the same spatial details for most pan-sharpening methods and is mainly dedicated to Intensity-Hue-Saturation based methods for which the following improvements in spectral quality were achieved: about 30% for the urbanized area and about 15% for the non-urbanized area.

Diatoms are important phototrophs in the worlds’ oceans contributing approximately 40% of the global primary photosynthetic production. This is partially explained by their capacity to exploit environments with variable light conditions, but there is limited knowledge on how diatoms cope with changes in the spectral composition and intensity of light. In this study, the influence of light quality and high irradiance on photosynthesis in the centric diatom Coscinodiscus granii was investigated with microscopic imaging and variable chlorophyll fluorescence techniques. Determination of the wavelength-dependent functional absorption cross-section of photosystem (PS) II revealed that absorption of blue light (BL) and red light (RL) was 2.3-fold and 0.8-fold that of white light (WL), respectively. Hence, BL was more efficiently converted into photo-chemical energy. Excessive energy from BL was dissipated via non-photochemical quenching (NPQ) mechanisms, while RL apparently induced only negligible NPQ even at high irradiance. A dose dependent increase of cells exhibiting an altered chloroplast distribution was observed after exposure to high levels of BL and WL, but not RL. However, no effective quantum yield of PSII was measured in the majority of cells with an altered chloroplast distribution, and positive Sytox green® death staining confirmed that most of these cells were dead. We conclude that although Coscinodiscus granii can sustain high irradiance it does not perform chloroplast high-light avoidance movements for photo-protection.

Indoor farming is becoming a popular alternative approach in food production to meet the demand of a growing world population. Under this production system, artificial light provides the main source of illumination in sustaining plant growth and development. The use of light-emitting diodes (LEDs) is a popular source of artificial light for indoor farms due to its narrow light spectra, modular design and energy efficiency. This study purposely assessed the effect of monochromatic LED light quality on the growth of three varieties of artichoke seedlings compared to greenhouse condition. Spectral quality assessment showed that photosynthetic photon flux density (PPFD) was highest under red LED light, but only a third of the total PPFD under natural light. Seedlings grown under red light showed 60-100% more shoot dry weight and were 67-115% taller than seedlings grown in the greenhouse. However, seedlings under blue or white light conditions showed 67-76% less in biomass compared to greenhouse-grown seedlings. Overall, plant response of seedlings under red light condition was much better compared to greenhouse-grown seedlings emphasizing the importance of red light spectral quality in plant growth and development. [ABSTRACT FROM AUTHOR]

Proton nuclear magnetic resonance spectroscopy of biofluids has become one of the key techniques for metabolic profiling and phenotyping. This technique has been widely used in a number of epidemiological studies and in a variety of health disorders. However, its utilization in brain disorders is limited due to the blood-brain barrier, which not only protects the brain from unwanted substances in the blood, but also substantially limits the potential of finding biomarkers for neurological disorders in serum. This review article focuses on the potential of localized in vivo proton magnetic resonance spectroscopy (1H-MRS) for non-invasive neurochemical profiling in the human brain. First, methodological aspects of 1H-MRS (data acquisition, processing and metabolite quantification) that are essential for reliable non-invasive neurochemical profiling are described. Second, the power of 1H-MRS-based neurochemical profiling is demonstrated using some examples of its application in neuroscience and neurology. Finally, the authors present their vision and propose necessary steps to establish 1H-MRS as a method suitable for large-scale neurochemical profiling in epidemiological research. [ABSTRACT FROM AUTHOR]

Pansharpening consists in merging a low-resolution multispectral image (MS) with a high spatial resolution panchromatic image (PAN) to produce a high resolution pansharpened MS image. It consists in enhancing spatially the low-resolution MS image by injecting the missing details provided by the high-resolution PAN image. In this paper, we propose a novel pansharpening approach based on decomposition/reconstruction processing using low-pass and high-pass filter banks. On the one hand, the low-pass approximation (taking into account the imaging system modulation transfer function MTF) of the pansharpened MS image is assumed to be equal to the original MS image in order to preserve the spectral quality. On the other hand, the high-pass filter allowing us to extract the high-frequency PAN details is designed as complementary filter to the low-pass one in order to provide perfect reconstruction in the ideal case. Quantitative assessment performed on reduced and full-resolution images are used to validate the proposed technique and compare it to state-of-art. Experimental results using Pléaides and GeoEye-1 data show that our proposed fusion schema outperforms the pre-existing methods visually as well as quantitatively. [ABSTRACT FROM AUTHOR]

We investigated the effects of light quality during night interruption (NI) on morphogenesis, flowering, and the transcription of photoreceptor genes in Petunia hybrida Hort. 'Easy Wave Pink' (a qualitative long-day plant, LDP). Plants were grown in a closed-type plant factory under a constant light intensity of 180 μmol·m·s PPF provided by white (W) light emitting diodes (LEDs) under long day (LD, 16 h light/8 h dark), short day (SD, 10 h light/14 h dark), or SD conditions with a 4 h NI using green (NI-G), blue (NI-B), red (NI-R), far-red (NI-Fr), or white (NI-W) LEDs at an intensity of 10 μmol·m·s PPF. Shoot length was greatest under NI-Fr. Flowering was observed under LD, NI-G, NI-Fr, and NI-W. The expression of photoreceptor genes was induced by NI. Specifically, phyA, phyB, and cry1 were more highly expressed under NI-G, NI-B, and NI-R compared to LD and SD. These results suggest that morphogenesis, flowering, and transcriptional factors are strongly affected by light quality during NI. [ABSTRACT FROM AUTHOR]

Keywords: B0 shimming; shim coil array; spectral quality; spectroscopic imaging EN B0 shimming shim coil array spectral quality spectroscopic imaging 1 2 2 12/22/21 20220101 NES 220101 Abbreviations 2HG d -2-hydroxyglutarate AC alternating current DC direct current MRSI MR spectroscopic imaging SNR signal-to-noise ratio In MRS and MR spectroscopic imaging (MRSI) the struggle between signal-to-noise ratio (SNR) and voxel size seems never ending. Spectroscopic imaging, B0 shimming, shim coil array, spectral quality Receiving AC MR signals with multiple closely fitting loops provides a high SNR, and using the same (and additional) loops with DC can locally homogenize the main magnetic field. [Extracted from the article]

There is a great deal of interest in clays in various fields of science and industry. In the literature, it can be easily seen that vibrational spectroscopic particularly FT-IR and NMR methods have been widely employed for the scientific studies of clays. However, especially not much data is available for Raman spectrum since it is difficult to obtain a good and interpretable spectrum. Most of the time, particle size or grain size is not considered as an element which can affect the quality of the Raman and NMR spectra. In this paper, we prepared clay samples having different grain sizes obtained from Ünye region and we observed the effect on the Raman and 29Si NMR spectral quality. [ABSTRACT FROM AUTHOR]

Comprehensive two-dimensional gas chromatography mass spectrometry (GC × GC–MS) offers excellent chromatographic separation performance and superior sensitivity. As such, it is eminently suitable for the analysis of complex biological samples. The applicability of a GC × GC instrument equipped with a fast-scanning qMS detector for large-scale untargeted metabolome analyses was investigated. We optimized the dimensions of an apolar × medium-polar column combination in order to meet detector requirements and to compromise between separation performance and analysis time. The final method enabled a sufficient separation ( R ≥ 1.2 or higher) of approx. 90% of all analytes detected in urine within less than 1 h. Using the qMS at maximum scan speed (20,000 u/s) and choosing a scan range of m/z 60–550, a data acquisition frequency of 33 Hz and usually at least 10–13 data points per 2 D peak above the baseline were achieved. Peak area as well as peak height could thus be determined precisely (mean RSD 2.5%). Spectral skewing was limited regarding the data points covering the upper peak half. As a consequence, peak apex spectra could be used for the alignment of analytes in different samples. The linear dynamic range was 1–2.5 orders of magnitude, depending on the analyte. In addition, the slow transition into saturation beyond the linear dynamic range made it possible to exploit an extended “working range” for relative quantification. Long-term stability of the system was demonstrated by the analysis of more than 300 human urine study samples for which detailed repeatability and intermediate precision data are provided. In summary, the GC × GC–qMS system proved to be applicable for untargeted large scale metabolome analyses. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the effect of changing light spectral quality, using colored shading nets, on the characteristics of tamarind (Tamarindus indica L.) leaf anatomy to obtain more conducive plants. Tamarind seedlings were grown under blue, white, black and red shade nets, in a completely randomized design. After 90 days, the leaves were evaluated anatomically and micromorphologically. Plants grown under white net had greater palisade parenchyma, abaxial epidermis cells and midrib thicknesses. Better results for adaxial epidermis and leaf blade were observed under white and blue nets. Higher stomatal density was obtained under blue and red nets. Tamarindus indica leaves present anatomical plasticity in response to changes in the radiation spectrum. In view of these results, the white and blue nets can be recommended to obtain plants more efficient to planting. [ABSTRACT FROM AUTHOR]

We examined the effects of ambient, non-stressing ultraviolet (UV)-B (280–315 nm) level combined with different intensities of photosynthetic active radiation (PAR, 400–700 nm) on the accumulation of the lignan (−)-hinokinin, in leaves and stems of Hydrocotyle leucocephala . Plants were exposed in sun simulators under almost natural irradiance and climatic conditions to one of four light regimes, i.e. two PAR intensities (906 and 516 μmol m −2 s −1 ) including or excluding UV-B radiation (0 and 0.4 W m −2 ). Besides hinokinin, we identified three chlorogenic acid isomers, one other phenolic acid, 12 quercetin, and five kaempferol derivatives in the H. leucocephala extracts. Hinokinin was most abundant in the stems, and its accumulation was slightly enhanced under UV-B exposure. We therefore assume that hinokinin contributes to cell wall stabilization and consequently to a higher resistance of the plant to environmental factors. Quercetin derivatives increasingly accumulated under UV-B and high PAR exposure at the expense of kaempferols and chlorogenic acids, which was apparently related to its ability to scavenge reactive oxygen species. In general, the concentration of the constituents depended on the plant organ, the leaf age, the light regimes, and the duration of exposure. The distribution pattern of the compounds within the examined organs was not influenced by the treatments. Based on the chemical composition of the extracts a principal component analysis (PCA) enabled a clear separation of the plant organs and harvesting dates. Younger leaves mostly contained higher phenylpropanoid concentrations than older leaves. Nevertheless, more pronounced effects of the light regimes were detected in older leaves. As assessed, in many cases the individual compounds responded differently to the PAR/UV-B combinations, even within the same phenylpropanoid class. Since this is the first report on the influence of light conditions on the accumulation of lignans in herbaceous plants, it opens many perspectives for a more precise elucidation of all involved biochemical and molecular processes. [ABSTRACT FROM AUTHOR]

Remote-sensing satellites provide both high-resolution panchromatic and low-resolution multi-spectral images. In this paper, a pixel-level multi-sensor image fusion technique is proposed for improving the spectral quality of the fused multi-spectral and panchromatic remote-sensing images. The proposed fusion technique integrates both the intensity, hue, and saturation (IHS) and the discrete wavelet frame transform (DWFT) techniques. IHS fusion technique can provide high spatial quality and the DWFT fusion technique is both aliasing free and translation invariant, but the color distortion in both techniques is noticeable. The proposed fusion technique can improve the spectral discrepancy of the fused images, while preserving the spatial quality to an acceptable level. Landsat-5 (TM) with Spot (Pan), Landsat-7 (ETM+), and IKONOS panchromatic and multi-spectral images have been fused using the proposed technique. The statistical analysis shows that this technique improves the fusion quality compared to the other known fusion techniques such as the conventional IHS, discrete wavelet transform (DWT), DWFT, and the integrated IHS and DWT. [ABSTRACT FROM AUTHOR]

Copyright of Gesunde Pflanzen is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study investigated the effects of a combination of light-emitting diodes (LEDs) that emit different bands of short wavelengths on the growth response of leaf lettuce ( Lactuca sativa var. crispa ) at the seedling stage (1–14 d old) and vegetative stage (15–28 d old). The wavebands included red (R; range: 623–673 nm), light red (Lr; range: 599–644 nm), blue (B; range: 427–478 nm), light-blue (Lb; range: 435–489 nm), cyan (C; range: 466–532 nm), green (G; range: 494–564 nm), and ultraviolet-A (UV-A; range: 383–426 nm). In the light treatments, a photon flux of 300 ± 12 (standard deviation [SD]) μmol m −2 s −1 was provided for 18 h d −1 at the seedling and vegetative stages with such LED light formulas (combinations) including LrLb (61.5% and 38.5%, respectively), RCB (42.8%, 30.0%, and 27.2%, respectively), LrLbG (49.0%, 36.1%, and 14.9%), and RBUV-A (52.9%, 37.0%, and 10.1%), with each fraction denoting the percentage of total photon flux. The air temperature, relative humidity, and CO 2 levels for all treatments were maintained at 22 ± 2 °C, 64 ± 8%, and 570 ± 75 ppm, respectively. The data obtained revealed the variability of light formula effects on lettuce plant physiological indices (including the number of leaves, leaf length, leaf area, dry mass, fresh mass, chlorophyll-a (chl-a) content, and nitrate content). Provision of RBUV-A and RCB LED irradiation during the vegetative stage could increase the shoot fresh mass of leaf lettuce. In addition, providing different LED light formulas to lettuce plants at the seedling and vegetative stages resulted in tremendous differences in nitrate contents, especially with the use of two light formulas with and without reversal of lighting sequence. Finally, the adoption of LrLbG or LrLb LED irradiation during different growth stages resulted in the lowest physiological indices of lettuce plants. [ABSTRACT FROM AUTHOR]

Highlights: [•] Supplemental LED lighting improved growth and morphology of cucumber seedlings. [•] Under high DLI the increased of blue photon flux had no effect on the seedlings. [•] Under low DLI the increased of blue photon flux decreased seedling's growth rate. [•] The decreased in growth rate was caused by the decreased of leaf area under low DLI. [•] Red LEDs are preferred as supplemental lighting for cucumber seedlings. [Copyright &y& Elsevier]

Content of thymol and carvacrol in Lippia graveolens essential oil was studied in response to variations in the spectral quality of light through the use of specific filters. Red, blue and transparent filters were used in the experiment. The plants responses were determined by internode distance and number of flowers. Responses in the essential oil were determined by thymol+carvacrol percentage and thymol:carvacrol ratio (T:C). The thymol+carvacrol percentage increased from 34% to 69% in red and from 34% to 87% in blue treatment. T:C ratio shows 1:1.5, 1:1.7 and 2.8:1 in control, red and blue treatments, respectively. Composition, especially T:C ratio, is an important factor in the quality of this essential oil because of its influence in biological activity. [ABSTRACT FROM AUTHOR]

Highlights: [•] We elucidate the relevance of ambient UV-B and PAR for saponin accumulation. [•] UV-B-induced flavonoid accumulation was monitored by fluorescence measurements. [•] Saponin and flavonoid accumulation was favoured by high PAR. [•] Contrary to flavonoids, saponins were not affected by UV-B. [•] Possible functions of saponins in plant protection from high PAR are discussed. [Copyright &y& Elsevier]

Advances in plant tissue culture methods with regard to lighting requirements are currently focused on the improved features of light-emitting diodes (LEDs). Over the years, the steady development of LED technology, with the emergence of new types of semi-conductor materials, has made it possible to apply it in an increasing number of new areas. As an alternative to conventional lighting systems, LED has been demonstrated to be an artificial flexible lighting source for plant tissue culture. Numerous studies have been conducted in order to investigate the effects of LED on plants, which have led to many satisfactory results. Various morphological, anatomical, and physiological attributes, such as shoot elongation, axillary shoot formation, somatic embryo induction, rhizogenesis, leaf anatomy, and photosynthetic abilities of plants grown in vitro have found to be regulated by spectral properties of LEDs. The present review gives an overview of the fundamentals of LEDs and describes their effects on in vitro plant growth and morphogenesis and their future potentials. [ABSTRACT FROM AUTHOR]

We report the development of innovative embedding procedures for the analysis of paint cross sections by attenuated total reflection (ATR) Fourier transform IR microscopy. This technique was chosen because it is widely employed for the characterization and spatial location of organic and inorganic components in artistic samples. Moreover, the performance of the technique may be critically affected by sample preparation in terms of surface morphology and the presence of contamination. First, we evaluated the use of KBr as a barrier to contamination by the embedding synthetic medium. In this way, the sample cross section can be polished by means of a sample holder, which allows a controlled pressure to be applied to the sample, thus improving the reproducibility and quality of the surface cross section. In addition, argon ion milling was used for the polishing of samples embedded in KBr, and provided very promising results in terms of surface planarity and reduction of superficial contamination by KBr. Finally, the use of NaCl as an alternative to KBr was proposed thanks to its advantages in terms of hygroscopicity, cost, and toxicity. In addition, cross sections embedded in NaCl were characterized by greater hardness, a feature that allowed us to obtain improved contact with the ATR crystal. [ABSTRACT FROM AUTHOR]

Multispectral (MS) images provided by Earth observation satellites have generally a poor spatial resolution while panchromatic images (PAN) exhibit a spatial resolution two or four times better. Data fusion is a means to synthesize MS images at higher spatial resolution than original by exploiting the high spatial resolution of the PAN. This process is often called pansharpening. The synthesis property states that the synthesized MS images should be as close as possible to those that would have been acquired by the corresponding sensors if they had this high resolution. The methods based on the concept Amélioration de la Résolution Spatiale par Injection de Structures (ARSIS) are able to deliver synthesized images with good spectral quality but whose geometrical quality can still be improved. We propose a more precise definition of the synthesis property in terms of geometry. Then, we present a method that takes explicitly into account the difference in modulation transfer function (MTF) between PAN and MS in the fusion process. This method is applied to an existing ARSIS-based fusion method, i.e., A trou wavelet transform-model 3. Simulated images of the sensors Pleiades and SPOT-5 are used to illustrate the performances of the approach. Although this paper is limited in methods and data, we observe a better restitution of the geometry and an improvement in all indices classically used in quality budget in pansharpening. We present also a means to assess the respect of the synthesis property from an MTF point of view. [ABSTRACT FROM AUTHOR]

We investigated the influence of light quality on in vitro germination and protocorm formation, and the effect of indole-3-acetic acid (IAA) and thidiazuron (TDZ) on proliferation of protocorm-like bodies (PLBs) and development of plantlets of Cyrtopodium glutiniferum Raddi. Germination was faster under white and blue light, and highest under green light. The protocorm developed more rapidly under white, blue, and green light. Continuous darkness delayed seed germination and reduced protocorm formation. Among the plant growth regulators (PGRs) tested for multiplying PLBs, shoots, and roots from protocorms, IAA proved to be superior. TDZ was effective in inducing PLB fresh weight accumulation, but not morphogenesis, unlike IAA. This study indicated that C. glutiniferum seedlings can be produced in vitro using asymbiotic seed germination techniques. High germination rate and protocorm yield can be obtained by initially cultivating C. glutiniferum seeds on medium without growth regulators under white light, or under white light supplemented with green or blue light. This culture system complies with commercial and conservation requirements for rapid and low-cost propagation. [ABSTRACT FROM AUTHOR]

Abstract: We investigated the influence of light quality on the leaf development of Alternanthera brasiliana Kuntze (Amaranthaceae) grown in vitro. Growth parameters including specific leaf mass, thickness, and leaf density were lowest in plants grown under red light. Blue light induced the largest number of leaves/plant, and the largest thickness and area of the leafblade. Green and red lights induced the smallest leaf areas. The thickness of the abaxial-face epidermis and spongy parenchyma of the plants was significantly reduced in plants grown under red light. The thickness of the palisade parenchyma and upper epidermis were significantly increased in plants grown under blue light, compared to the other fluorescent-light treatments. The specific spectral band also influenced the differentiation of mesophyll cells. In the dark and under red light, the mesophyll was homogenous; and in the dark and under green light, the leaves were more compact. Under blue light, the cells displayed the characteristic palisade morphology. The results showed that the increase of a specific parenchyma type was related to a specific spectral band. All spectral-quality treatments reduced the numbers of stomata and trichomes. The results for green light were in some respects similar to those for red light, and in other respects similar to those for blue light, probably because phytochromes and cryptochromes are green-light receptors. This study indicated that Alternanthera plants have strong morphological plasticity induced by light. The results suggest that high-quality Alternanthera can be achieved by culturing the plants in vitro under a combination of blue and red light. [ABSTRACT FROM AUTHOR]

In this paper, the phase-noise performance of optically generated electrical signals based on external optical modulation techniques is investigated theoretically and experimentally. Mathematical models are developed to represent perturbations on the transmitted optical signal caused by the phase fluctuations of the electrical drive signal applied to the external modulator and the optical carrier that feeds the external modulator. Closed-form expressions of the power spectral density (PSD) for the electrical signals, generated both locally and remotely, are derived. The calculated PSD of the locally generated electrical signal indicates that its phase noise is determined only by the phase noise of the electrical drive signal. The PSD of the remotely generated signal shows that its spectral quality is also affected by the chromatic dispersion of the fiber and the optical carrier linewidth. An experimental setup that can generate a millimeter-wave (mm-wave) signal, continuously tunable from 32 to 60 GHz using an electrical drive signal tunable from 8 to 15 GHz, is built. The spectra of the generated millimeter-wave signal are measured for both locally and remotely generated electrical signals, with optical carriers of different linewidths. The theoretical results agree with the experimental measurements [ABSTRACT FROM PUBLISHER]

We have successfully demonstrated a one-step laser process of fabricating fiber Bragg grating arrays directly through fiber buffer. A new polysiloxane-based buffer provides high 244-nm transmission and showed no degradation due to UV irradiation or thermal annealing as verified by Weibull analysis of tension tests. The FBG array can withstand over 400-kpsi tension tests and 220degC temperature. The spectral quality of the FBG is compatible with the FBGs currently used by the sensing industry and, therefore, can be interrogated with existing instruments. The laser fabrication process is robust with no coating, stripping, or recoating required [ABSTRACT FROM PUBLISHER]

We evaluate the feasibility, benefits, and operating parameters of a quasimonochromatic beam for a newly developed x-ray cone beam computed mammotomography application. The value of a near monochromatic x-ray source for fully 3D dedicated mammotomography is the expected improved ability to separate tissues with very small differences in attenuation coefficients while maintaining dose levels at or below that of existing dual view mammography. In previous studies, simulations for a range of tungsten tube potentials, K-edge fitter materials, fitter thicknesses, and a 12 cm uncompressed breast, with a digital flat-panel CsI(Tl) detector model, indicated that thick, rare earth filter materials may provide optimized image quality. Figures of merit computed included: lesion contrast under different filtering conditions; ratio of measured lesion contrast with and without filtering; and exposure efficiency (SNR² /exposure). Initial experiments are performed with a custom built x-ray mammotomography system, cerium foil filters, and plastic breast and lesion tissue-equivalent slabs. Simulation results showed that tube potentials of 50-70 kVp with filters of Z = 57-63 yielded quasimonochromatic x-ray spectra with improved FOMs. Initial experimental measurements corroborate simulation results in that, relative trends and rank order of contrast ratios and exposure efficiency were in agreement. These studies show that this approach can be implemented practically with simple hardware and yield improved exposure efficiency versus the unfiltered or minimally filtered case. [ABSTRACT FROM AUTHOR]

Copyright of American Journal of Potato Research is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Plants will be an important component of future long-term space missions. Lighting systems for growing plants will need to be lightweight, reliable, and durable, and light-emitting diodes (LEDs) have these characteristics. Previous studies demonstrated that the combination of red and blue light was an effective light source for several crops. Yet the appearance of plants under red and blue lighting is purplish gray making visual assessment of any problems difficult. The addition of green light would make the plant leave appear green and normal similar to a natural setting under white light and may also offer a psychological benefit to the crew. Green supplemental lighting could also offer benefits, since green light can better penetrate the plant canopy and potentially increase plant growth by increasing photosynthesis from the leaves in the lower canopy. In this study, four light sources were tested: 1) red and blue LEDs (RB), 2) red and blue LEDs with green fluorescent lamps (RGB), 3) green fluorescent lamps (GF), and 4) cool-white fluorescent lamps (CWF), that provided 0%, 24%, 86%, and 51% of the total PPF in the green region of the spectrum, respectively. The addition of 24% green light (500 to 600 nm) to red and blue LEDs (RGB treatment) enhanced plant growth. The RGB treatment plants produced more biomass than the plants grown under the cool-white fluorescent lamps (CWF treatment), a commonly tested light source used as a broad-spectrum control. [ABSTRACT FROM AUTHOR]

• Background and Aims Plants adjust the distribution of photosynthetic capacity and chlorophyll to canopy density. The importance of the gradient in the red : far-red ratio (R : FR) relative to the irradiance gradient was studied for its perception with respect to this partitioning of photosynthetic resources. Whether the relative importance of these two signals varied between six species of different growth habit (Phaseolus vulgaris, Lysimachia vulgaris, Hedera helix, Ficus benjamina, Carex acutiformis and Brachypodium pinnatum) was investigated further.• Methods Single leaves of plants were shaded in daylight by a spectrally neutral filter or a leaf. In another experiment, leaves were treated with supplemental FR. In most cases, treatment effects were evaluated after 2 weeks.• Key Results Nitrogen and photosynthetic capacity (Amax) per leaf area, parameters pertaining to between-leaf resource partitioning, were strongly reduced in neutral shade but not additionally by spectral leaf shade. Supplemental FR reduced these parameters also, except in Carex. Acceleration of induction of senescence was observed in spectral leaf shade in primary bean leaves. Amax per unit chlorophyll, a parameter pertaining to within-leaf resource partitioning, was reduced in neutral shade, but not in spectral leaf shade or supplemental FR.• Conclusions Signalling mechanisms associated with perception of the R : FR gradient in canopies were less important than those associated with the irradiance gradient for between-leaf and within-leaf partitioning of photosynthetic resources. The relative importance of the signals differed between species because Carex was the only species for which no indications were found for an involvement of the spectral gradient in perception of canopy density. [ABSTRACT FROM AUTHOR]

Objectives: A dual-mode Single Photon Emission Computed Tomography (SPECT)/X-ray CT (XCT) system for full-field mammotomography is proposed for evaluation of breast lesions, where dual-view X-ray mammography has proven to be ineffective or inconclusive, particularly in radiographically dense breasts. Investigated design parameters include combined SPECT/XCT system geometry, X-ray focal spot size, tube loading, kVp, filtration, and detector type to determine operating parameters for a novel quasi-monochromatic X-ray beam for use in X-ray computed mammotomography that would use a dose equal to that from dual view mammography and that could be combined in a dual-mode system with SPECT. Methods: The relatively compact design of the hybrid SPECT/XCT will allow both systems to rotate on the same gantry below a patient. The hybrid system will be composed of a versatile, goniometer-based SPECT gantry, and an XCT system with a fixed position tungsten target, cone-beam geometry and digital flat panel detector frame nearly orthogonal to the SPECT system. The X-ray beam was modeled by xSpect, a semi-empirical simulation code for X-ray production, attenuation, and detection. The idealized operating parameters for the quasi-monochromatic beam were determined by evaluating a beam hardening (minimum) figure of merit (FOM) along with quantitative spectral characteristics, and an exposure efficiency (maximum) FOM. These FOMs were evaluated in 8–16 cm thick uncompressed breasts. Filters with atomic numbers (Z) from 51–65 with 10th to 1000th value attenuating layer thicknesses were modeled, while considering tube loading limitations. Results: Using a tungsten target, increased tube potential and filtration can yield minimal beam hardening with improved exposure efficiency and contrast for various thicknesses of uncompressed breasts. Optimal tube operating range between 50–70 kVp with filter thickness of between 100th and 500th value layer for Z filters 56–62 result in optimized FOMs while remaining at or below expected dose of two-view X-ray mammography for the entire breast. Mean quasi-monochromatic beam energies were near 40 keV, with beam widths of <15% FWHM. Diminishing improvements are seen for filters greater than Z=65 and for thicknesses greater than the 500th value layer. Heavy filtration also demonstrated near-independence of FOM outcomes based on breast size. Conclusion: Simulated data show that a quasi-monochromatic beam with minimal beam hardening can readily be generated. Given the small expected source-image distance, it is geometrically feasible for the XCT system to be mounted on the SPECT gantry so that simultaneous SPECT/XCT images of a pendant, uncompressed breast can be obtained with identical imaging geometries. [Copyright &y& Elsevier]

Light irradiation had remarkable effects on the callus growth of Cistanche deserticola and biosynthesis of phenylethanoid glycosides (PeG). After 30 days of culture, the callus biomass and production of PeG reached 15.5 g dry weight (DW)/l and 1.7 g/l, respectively, at its light saturation point (24 μmol/m2 s). The callus cultured under blue light at 435 nm gave both the highest biomass (18.4 g DW/l) and production of PeG (2.4 g/l), which were 19 and 41% higher than those obtained under white light. [Copyright &y& Elsevier]

Cuttings of the southeast Asian tropical rain forest tree species, Pongamia pinnata (L.) Pierre were raised in growth chambers providing a photosynthetic photon flux density (PPFD) of 60 μmol m−2 s−1 with either a low or a high red:far-red light ratio (LR and HR, repectively). The chambers were supplied with air containing CO2 at a concentration of either 400 (LR4 and HR4, respectively) or 800 μmol mol−1 (HR8 and LR8, respectively). After 4 months, leaf morphology and photosynthetic characteristics were determined. Relative to HR4, the LR4 treatment increased leaf area and total chlorophyll concentration (Chl) by 24 and 25%, respectively, but reduced leaf mass per unit area (LMA) by 19%. Elevated [CO2] significantly increased leaf area and LMA but did not affect Chl of LR or HR plants. Leaf nitrogen concentration was unaffected by the red:far-red light ratio but decreased significantly in seedlings in the elevated [CO2] treatment. Photosynthesis measured in situ under the growth conditions of ambient light and [CO2] (Aamb) was 30% lower on an area basis and 14% lower on a mass basis in LR4 plants than in HR4 plants. Elevated [CO2] reduced the activity of ribulose-1,5-bisphosphate carboxylase/oxygenase and thus decreased light-saturated photosynthetic rate in both HR and LR plants. Elevated [CO2] increased mean leaf area and decreased respiration rates in both LR and HR plants. The LR8 plants had significantly higher Aamb than LR4 plants, but similar Aamb to HR8 plants. [ABSTRACT FROM PUBLISHER]

The effect of continuous lighting (CL, 24 h) and light spectrum on growth and nutritional quality of arugula (Eruca sativa), broccoli (Brassica oleracea var. italic), mizuna (Brassica rapa. var. nipposinica), and radish (Raphanus sativus var. radicula) were investigated in growth chambers under light-emitting diode (LED) and fluorescent lighting. Microgreens were grown under four combinations of two photoperiods (16 h and 24 h) providing daily light integral (DLI) of 15.6 and 23.3 mol m−2 day−1, correspondingly) with two light spectra: LED lamps and fluorescent lamps (FLU). The results show that fresh and dry weights as well as leaf mass per area and robust index of harvested arugula, broccoli, mizuna, and radish seedlings were significantly higher under CL compared to 16 h photoperiod regardless of light quality. There were no visible signs of leaf photodamage. In all CL-treated plants higher chlorophyll a/b and carotenoid-to-chlorophyll ratios were observed in all plants except mizuna. CL treatment was beneficial for anthocyanin, flavonoid, and proline accumulation. Higher activities of antioxidant enzymes (catalase, superoxide dismutase, ascorbate peroxidase, and guaiacol peroxidase) were also observed in CL-treated plants. In most cases, the effects were more pronounced under LED lighting. These results indicate that plants under mild oxidative stress induced by CL accumulated more non-enzymatic antioxidants and increased the activities of antioxidant enzymes. This added nutritional value to microgreens that are used as functional foods providing health benefits. We suggest that for arugula, broccoli, mizuna, and radish, an LED CL production strategy is possible and can have economic and nutritional benefits. [ABSTRACT FROM AUTHOR]

Spectral characteristics of solar radiation have a major role in plant growth and development and the overall metabolism, including secondary metabolism, which is important for the accumulation of health-promoting phytochemicals in plants. The primary focus of this study was to determine the effect of spectral characteristics of solar radiation on the nutritional quality of lettuce (Lactuca sativa L., cv. red leaf 'New Red Fire' and green leaf 'Two Star' and tomato (Solanum lycopersicum L., cv. BHN-589) grown in high tunnels in relation to the accumulation of essential nutrients and phytochemicals. Solar spectrum received by crops was modified using photo-selective poly covers. Treatments included commonly used standard poly, luminescence poly (diffuse poly), clear poly, UV blocking poly, exposure of crops grown under the standard poly to full sun 2 weeks prior to harvest (akin to movable tunnel), and 55% shade cloth on the standard poly. All the poly covers and shade cloth reduced the PAR levels in the high tunnels, and the largest reduction was by the shade cloth, which reduced the solar PAR by approximately 48%. Clear poly allowed the maximum UV-A and UV-B radiation, while standard poly allowed only a small fraction of the solar UV-A and UV-B (between 15.8% and 16.2%). Clear poly, which allowed a higher percentage of solar UV-A (60.5%) and UV-B (65%) than other poly covers, increased the total phenolic concentration and the antioxidant capacity in red leaf lettuce. It also increased the accumulation of flavonoids, including quercetin-3-glucoside, luteolin-7-glucoside, and apigenin-3-glucoside in red leaf lettuce, compared to the standard poly. Brief exposure of crops grown in high tunnels to full sun prior to harvest produced the largest increase in the accumulation of quercetin-3-glucoside, and it also resulted in an increase in luteolin-7-glucoside and apigenin-3-glucoside in red leaf lettuce. Thus, clear poly and brief exposure of red leaf lettuce to the full sun, which can increase UV exposure to the plants, produced a positive impact on its nutritional quality. In contrast, shade cloth which allowed the lowest levels of solar PAR, UV-A and UV-B relative to the other poly covers had a negative impact on the accumulation of the phenolic compounds in red leaf lettuce. However, in green leaf lettuce, luminesce poly, clear poly, UV-block poly, and shade treatments increased the accumulation of many essential nutrients, including protein, magnesium, and sulfur in green leaf lettuce compared to the standard poly. Poly cover treatments including shade treatment did not affect the accumulation of either carotenoids (lutein, β-carotene, and lycopene) or essential nutrients in mature tomato fruits. The results show that clear poly cover can enhance the accumulation of many phenolic compounds in red leaf lettuce, as does the brief exposure of the crop to the full sun prior to harvest. Thus, UV radiation plays an important role in the accumulation of phenolic compounds in red leaf lettuce while the overall spectral quality of solar radiation has a significant influence on the accumulation of essential nutrients in green leaf lettuce. [ABSTRACT FROM AUTHOR]

[Display omitted] • Photon flux density and wavelength affect growth, pigments and volatile compounds. • Light intensity of 139 μmol m−2 s−1 is optimal for the growth of plantlets. • White LED and fluorescent light are effective for growth and dry weight accumulation. • Monochromatic red, blue and yellow lights inhibited growth. • White LED increased linalool, green and yellow monochromatic increased massoia lactone. Aeollanthus suaveolens Mart. ex Spreng. (Lamiaceae) is an aromatic plant of African origin and is widely used in folk medicine due to its anticonvulsant and sedative effects. The aim of the study was to establish whether photon flux density (PFD) and wavelength, provided by light emitting diodes (LEDs), affect plantlet growth, photosynthetic pigment, and volatile organic compound (VOC) accumulation in Aeollanthus suaveolens. Nodal segments were grown under different PFDs (20, 57, 78, 102 and 139 μmol m−2 s−1) obtained with white LEDs lamps and under different LEDs light spectra as follows: white, green, yellow, blue, red, and combinations of red and blue (2.5R:1B; 1R:2.5B; 1R:1B) and cool white fluorescent lamps. The different light intensities affected the growth and production of photosynthetic pigments and volatile organic compounds. Plantlets grown under a PFD of 139 μmol m−2 s−1 showed greater dry weight accumulation and growth than those raised under other PFDs. The chlorophyll and carotenoid contents increased with a PFD of 20 μmol m−2 s−1. Light quality also affected plantlet growth. White LEDs light and fluorescent light were equally effective for growth and dry weight accumulation. Monochromatic red, blue, and yellow lights inhibited growth in Aeollanthus suaveolens. The concentrations of photosynthetic pigments from A. suaveolens plantlets were significantly affected by different wavelengths. Yellow wavelengths favored the production of photosynthetic pigments. The accumulation of VOCs was influenced by PFD and spectral quality. [ABSTRACT FROM AUTHOR]

Four plant species (Chamerion angustifolium, Digitalis purpurea, Brachypodium sylvaticum and Plantago lanceolata) which have previously been shown to demonstrate contrasting photosynthetic acclimatory responses to the light environment (Murchie & Horton 1997, Plant, Cell and Environment 20, pp. 438–448) were analysed at a biochemical level. Plants were grown under low irradiance with a shade-type spectrum (LFR: 50μmol quanta m–2 s–1), moderately high white light (MW: 300μmol quanta m–2 s–1) and low irradiance white light (LW: 50μmol quanta m–2 s–1). The effects of light quality upon chlorophyll content and photosynthetic capacity were found to be species-dependent. A far-red dependent reduction in chlorophyll was found in three species, and an irradiance-dependent reduction was found in B. sylvaticum, which showed the greatest alteration in the xanthophyll cycle pool size of all species tested under these conditions. Chlorophyll a/b ratios were sensitive to both light quality and quantity in C. angustifolium and D. purpurea, being highest in MW, lowest in LFR, and intermediate in LW, whilst the other species showed no response. Ratios of photosystem II to photosystem I (PSII and PSI) demonstrated a strong irradiance-associated increase in all species except B. sylvaticum, whereas an increase in PSII/PSI in LFR compared to LW conditions was present in all species. A change in chlorophyll a/b was not always associated with a change in PSII/PSI, suggesting that the level of LHCII associated with each PSII varied in some species. Cytochrome f content showed an irradiance-dependent effect only, indicating a relationship with the capacity of electron transport. It is concluded that differing strategies of acclimation to the light environment demonstrated by these species results from differing strengths of expression of a series of independently regulated changes in the levels of photosynthetic components. [ABSTRACT FROM AUTHOR]

Polyunsaturated fatty acids (i.e. linoleic acid [18:2], linolenic acid [18:3]) in triacylglycerols (TAG) of soybean seeds increase more during reproductive development under simulated shadelight: i.e., light with reduced blue and/or increased far‐red (Britz and Cavins 1993). Elevation of 18:2 and 18:3 is matched by corresponding reduction of oleic acid (18:1), consistent with observations that total seed oil remains constant. We therefore tested the hypothesis that spectral quality affects the activity of the omega‐6 and/or omega‐3 desaturases involved in TAG biosynthesis. Membranes were isolated from developing soybean cotyledons 24–31 days after flowering. Separate fractions, enriched for chloroplasts and endoplasmic reticulum (ER) respectively, were obtained by sucrose gradient centrifugation and incubated in an in vitro desaturase assay system containing 14C‐18:1–CoA at room temperature. Omega‐6 and omega‐3 desaturase activity was calculated from the rate of formation of 14C‐18:2 and 14C‐18:3. Radioactive 18:2 and 18:3 were recovered only from phosphatidylcholine (PC) in both ER and chloroplast membranes, consistent with membrane‐bound desaturases with specificity towards PC. The specific activity of omega‐6 desaturase was high in ER membranes from seeds matured under light sources that promote a canopy shade response, but was reduced in membranes from seeds matured under lamps (high blue and low far‐red emission) previously shown to reduce the level of 18:2 in seed oil by 50%. Chloroplast membranes possessed both omega‐6 and omega‐3 desaturases. Light appeared to have little or no effect on the activity of chloroplast desaturases. [ABSTRACT FROM AUTHOR]

UV-B-sensitive (Poinsett) and -insensitive (Ashley) cultivars of cucumber (Cucumis sativus L.) were grown in growth chambers at 600 μmol m-2 s-1 of photosynthetically active radiation provided by metal halide (MH) or high pressure sodium/deluxe (HPS/DX) lamps. Plants were irradiated 15 days from seeding for 6 h per day under 18.2 kJ m-2 day-1 of biologically effective UV-B (UV-BBE) radiation. One of the most pronounced effects of UV-B was a 27 to 78% increase in phenylalanine ammonia-lyase (PAL) activity. UV-B also increased total polyamines. Catalase and superoxide dismutase varied greatly in their response to UV-B. There were no interactive effects on PAL or catalase activity, or total polyamines. There was a UV × PAR source interaction for superoxide dismutase activity. UV-B increased chlorosis and decreased height, dry weight and leaf area. Stem elongation, biomass production, leaf enlargement and chlorosis were greater under HPS/DX lamps than under MH lamps. Chlorosis was greater in Poinsett than in Ashley and in lower leaves than in upper ones. Aside from chlorosis, there were no interactive effects of UV-B. PAR source or cultivar on any of the growth parameters measured, suggesting that the growth response of cucumber seedlings to UV-B is unaffected by PAR source or cultivar. Similarly, except for SOD activity, the biochemical response to UV-B was also not influenced by PAR source or cultivar. [ABSTRACT FROM AUTHOR]

The response of pinto bean (Phaseolus vulgaris L.) plants to single application of brassins (10 μg) in the second‐internode assay was determined under equal levels (90 μE m−2 s−1) of photosynthetically active radiation in a controlled environment provided by cool‐white fluorescent (CWF) lamps, incandescent (INC) lamps, or a combination of the two sources. Treatment of the second internode with brassins produced a characteristic swelling of the treated internode irrespective of the spectral source used. However, the increase in radial growth of the upper portion of brassin‐treated internodes from plants grown under INC lamps was more than 50% greater than those of plants grown under CWF lamps for 7 days. Spectral quality also had a marked effect on the rate and extent of internode elongation. Brassin‐treated internodes of plants grown for 7 days under CWF lamps were more than twice as long as those of control plants, whereas those from INC or CWF + INC grown plants were significantly shorter than those of control plants. The effect of brassins was largely confined to the treated internode. [ABSTRACT FROM AUTHOR]