Pigment Ratios Research Articles

Preparation of polyvinyl alcohol/carboxymethyl cellulose sodium/chitosan paper-based antimicrobial indicator cards using mixed anthocyanin with stability-colorimetric sensitivity: Monitoring freshness of carp

In this study, an anthocyanin solution with both high stability and sensitivity was successfully prepared through a blending method, and the optimal ratio was determined. Ultraviolet-visible spectroscopy analysis demonstrated that an increase in the proportion of black bean peel anthocyanins resulted in a deeper color and a more pronounced color change effect. Moreover, the stability of the blended anthocyanins was markedly enhanced with an increase in the proportion of purple cabbage anthocyanins, resulting in a slower decomposition rate under light, temperature, oxidation, and varying pH conditions. The blended anthocyanins, employed as a pH indicator, were utilized to prepare an antibacterial indicator card. It was observed that the mechanical properties of the coated paper remained unaltered by the ratio of the mixed pigments. The mixed pigments enhanced the stability of the antibacterial indicator card with respect to environmental fluctuations while facilitating more rapid and sensitive color transitions in the presence of ammonia and under disparate pH conditions. The application of indicator cards with five different anthocyanin ratios to fish resulted in a shelf life extension of 1–2 days compared to the control group and enabled real-time monitoring of fish freshness. A comprehensive evaluation demonstrated that the optimal indicator performance was attained when the mass ratio of black bean peel anthocyanins to purple cabbage anthocyanins was 1:1.

Preparation and characterization of novel natural pigment-indicating film: Application in kiwifruit freshness monitoring

The marketability of natural pigment-based indicator films is impeded by their weaker color rendering and stability compared with synthetic pigments. Here, we developed novel colorimetric indicators by blending polyvinyl alcohol (PVA) with carboxymethyl cellulose (CMC) and combining alizarin and curcumin. Compared with the individual materials, the PVA and CMC composite films demonstrated superior thermal stability and water resistance. The manufacturing process of these colorimetric indicators was optimized using response surface methodology. The optimum conditions were as follows: PVA at 3.92 g/100 mL; plate pour amount, 48.6 mL; pigment content, 5.8 g/100 mL; pigment ratio, 0.76. The optimized film showed a robust response to CO2 (a color difference of 65.06 ± 2.43). The color difference of the optimized film improved by 98.5 % and 16.86 % for kiwifruit stored at room and low temperatures, respectively. This substantial color change aids in identifying the optimal consumption window for kiwifruit, boosting indicator precision and kiwifruit freshness accuracy.

Phytoplankton communities quantified from hyperspectral ocean reflectance correspond to pigment-based communities

Community detection analysis is a powerful tool to separate groups of samples that are similar based on their composition. Here, we use a paired global dataset of in-water hyperspectral remote sensing reflectance (Rrs) spectra and high-performance liquid chromatography (HPLC) pigment concentrations to investigate the similarity in phytoplankton composition of the communities detected from each method. Samples were separated into optical communities using network-based community detection analysis applied to the Rrs residual (δRrs), which is calculated by subtracting a modeled hyperspectral Rrs spectrum from a measured hyperspectral Rrs spectrum. The δRrs spectrum accentuates short spectral scale features (<=10 nm) that should be related to phytoplankton pigment composition metricsTo test whether these optical communities correspond to phytoplankton communities, we also used network-based community detection analysis to separate HPLC pigment-based communities from twelve accessory pigment ratios to total chlorophyll-a. Our results demonstrate that three distinct phytoplankton communities can be separated from both hyperspectral Rrs data and HPLC pigment data and that a majority of these samples (74%) were assigned to the same communities. Differences in community assignment were also identified and potential sources for discrepancies were discussed. Importantly, the optical communities assigned here offer a new tool for assessing phytoplankton community composition on global scales using hyperspectral Rrs observations, such as those provided by the Ocean Color Instrument (OCI) on NASA’s new Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) satellite.

Extracellular vesicle-mediated secretion of chlorophyll biosynthetic intermediates in the cyanobacterium Leptolyngbya boryana.

Extracellular vesicles (EVs) are derived from the outer membrane (OM) in Gram-negative bacteria and have diverse physiological functions. EV-mediated secretion of monovinyl protochlorophyllide (MV-Pchlide), the chlorophyll a (Chl) biosynthetic intermediate, was previously reported in a mutant lacking dark-operative Pchlide reductase in the cyanobacterium Leptolyngbya boryana. This study showed a detailed characterization of EVs from the wild-type (WT) of L. boryana grown under photoautotrophic and dark heterotrophic conditions, focusing on the accumulation of Chl intermediates. WT L. boryana cells produce two types of EVs, low-density EVs (L-EVs) and high-density EVs (H-EVs), both under light and dark conditions. L-EVs and H-EVs showed distinct morphological features and protein compositions. L-EVs from cells grown under both light and dark conditions commonly contained carotenoids, ketomyxol glycoside, and zeaxanthin, as major pigments. Based on the protein compositions of EVs and other cellular membrane fractions, L-EVs and H-EVs are probably derived from low-density OM and high-density OM interacting with cell walls, respectively. Fluorescence detection of pigments was applied to EVs, and the two Chl intermediates, protoporphyrin IX and protoporphyrin IX monomethyl ester, were commonly detected in both L-EVs from light- and dark-grown cells, whereas L-EVs from dark-grown cells contained additional MV-Pchlide, MV-protopheophorbide, and pheophorbide. The pigment ratios of L-EVs to the total culture medium of the Chl intermediates were much higher than those of carotenoids, suggesting an active transport of the Chl intermediates from the thylakoid membrane to L-EVs. Cyanobacterial EVs may play a novel role in alleviating the accumulation of Chl intermediates in cells. (248 words).

Влияние биологических регуляторов роста на содержание фотосинтетических пигментов Campanula alliariifolia

Abstract. The purpose is to study the effectiveness of the action of the natural signaling molecule salicylic acid (SA) and Bacillus subtilis (Bs) on the ratio of photosynthetic pigments (PhSP) in plant materials (leaves) of Campanula alliariifolia Willd. and its decorativeness. Methods. Using spectrophotometric techniques, an analysis was carried out of the dynamics of the content of pigments (chlorophyll a, chlorophyll b and carotenoids) under the influence of a strain of the bacterium Bacillus subtilis, isolated at the Bashkir Scientific Research Institute of Agriculture of the Federal Research Center of the Russian Academy of Sciences (Ufa) from the arable soil layer of the Republic of Bashkortostan, and its combination with salicylic acid during the growing season. Scientific novelty. The influence of the B. subtilis strain separately and together with salicylic acid on the physiological parameters and decorative properties of Campanula alliariifolia in the conditions of the Bashkir Cis-Ural was studied. Results. The content and ratio of PhSP in dynamics (phases of budding, flowering and fruiting) were analyzed. It was revealed that inoculation of C. alliariifolia plants with Bacillus subtilis significantly increases the amount of carotenoids during the flowering phase. During the fruiting phase, the maximum content of PhSP was noted in the Bs + SA variant of the experiment. Two-factor analysis of variance showed that the significant influence of factor A (vegetation phase), factor B (different experimental options), and the degree of total influence of two factors (A × B) on the content of PhSP in samples of campanula leaves is statistically significant for the studied indicators. It was found that inoculation with the B. subtilis strain maximized indicators such as the abundance of flowering and the density of bellflower inflorescences, thereby improving the decorativeness of C. alliariifolia in the conditions of the Bashkir Cis-Ural.

Impacts of temperature and coating pigment ratios on the corrosion rate of ss400 steel

Steel is the primary shipbuilding material; however, it erodes quickly. Adequate protection requires hard, durable, and adhesive coatings. This study examines how aluminium-graphite pigment and heat treatment affect epoxy-coated SS400 steel plate corrosion, adhesion, and coating resilience. This study used a 1:1 and 3:1 pigment ratio with 100°C and 150°C heat treatment. The coating layer was 250 μm thick and comprised 80% epoxy and 20% aluminum-graphite. The maximum adhesion strength, 19.62 MPa, was achieved with an aluminium-graphite pigment ratio of 1:1 and 100°C heat treatment. The top coating resistance was 6.86 Joules under identical conditions. The lowest corrosion rate, 0.047 mmpy, was at a 3:1 aluminum-graphite ratio and 150°C heat treatment. This discovery has significant consequences for shipbuilding steel corrosion resistance.

Skeletonema marinoi ecotypes show specific habitat-related responses to fluctuating light supporting high potential for growth under photobioreactor light regime.

Diatoms are a diverse group of phytoplankton usually dominating areas characterized by rapidly shifting light conditions. Because of their high growth rates and interesting biochemical profile, their biomass is considered for various commercial applications. This study aimed at identifyingstrains with superior growth in a photobioreactor (PBR) by screening the natural intraspecific diversity of ecotypes isolated from different habitats. We investigated the effect of PBR light fluctuating on a millisecond scale (FL, simulating the light in a PBR) on 19 ecotypes of the diatom Skeletonema marinoi isolated from the North Sea-Baltic Sea area. We compare growth, pigment ratios, phylogeny, photo-physiological variables and photoacclimation strategies between all strains and perform qPCR and absorption spectra analysis on a subset of strains. Our results show that the ecotypes responded differently to FL, and have contrasting photo-physiological and photoprotective strategies. The strains from Kattegat performed better in FL, and shared common photoacclimation and photoprotection strategies that are the results of adaptation to the specific light climate of the Kattegat area. The strains that performed better with FL conditions had a high light (HL)-acclimated phenotype coupled with unique nonphotochemical quenching features. Based on their characteristics, three strains were identified as good candidates for growth in PBRs.

Response surface methodology‒guided color simulation of plant-based meat analogues before and after oven cooking: prickly pear cactus, mugwort, and sweet pumpkin pigments

This research aimed to find natural pigments that would give meat analogues the color of real meat, both before and after oven cooking. The natural pigments used were from the prickly pear cactus, mugwort, and sweet pumpkin. The key ingredient was the prickly pear cactus pigment, which consists mainly of betalains and loses its red color when exposed to heat. Yellow pigment derived from sweet pumpkin and green pigment derived from mugwort worked in synergy, and this mixture gave the analogues the characteristic brown hue of well-cooked meat. The optimal pigment ratios were established using response surface methodology, tailored for different meat types and cooking conditions. Quantitative findings revealed that the P3M1S1 combination at a 3% concentration provided the coloring most like that of real meat before and after cooking. In addition, sensory assessments confirmed that this mixture gave tasters an experience almost identical to that of eating actual meat. Response surface methodology validated the predictive accuracy, with deviations of less than 5% for color and less than 10% for sensory attributes. In addition, changes in important compounds responsible for color were identified when heat reduced the amounts of betalain in prickly pear cactus pigment and chlorophyll in mugwort pigment.

Вплив кліматичних умов на вміст та співвідношення фотосинтетичних пігментів у рослин роду Carlina L.

Вплив кліматичних умов на вміст та співвідношення фотосинтетичних пігментів у рослин роду Carlina L.

Chestnut shell dyes extracted by deep eutectic solvent in green dyeing of silk fibers for enhanced washable, antibacterial and UV protection properties

As an important biomass resource, chestnut shells are often discarded and wasted. In this study, we report an innovative, low-cost and environmentally friendly approach of dyeing silk fibers with natural pigments extracted from chestnut shells using deep eutectic solvent (DES) and imbuing them with antibacterial and ultraviolet protection properties. To improve the extraction ratio of chestnut shell pigment, DES of choline chloride and urea (ChCl/Urea) with high solubility performance was adopted to extract pigment from chestnut shells and then directly used for silk dyeing. The color spectral curve, washing durability, antibacterial and ultraviolet resistance of dyed silk were tested and compared with the silk dyed by metal salt mordant. The result showed that compared with ethanol extraction, DES extraction method had a higher extraction rate and better stability of the extraction solution. Owing to the swelling, surface modification and high permeability of ChCl/Urea DES to silk fibers, the affinity between the pigment solution and silk fibers was enhanced, and the pigment molecules entered the amorphous area inside the silk fibers, forming a tight bond with the fiber matrix during dyeing. Therefore, the dyed silk fabric has excellent washing durability and soft luster, and the color strength (K/S) remained unchanged after three washings. Meanwhile, the antibacterial activity and ultraviolet protection coefficient of silk dyed with chestnut shell pigment reached above 97% and 42.26, respectively, which exhibits excellent antibacterial and ultraviolet protection properties.

Quantitative analysis of chlorophyll in Catalpa bungei leaves based on partial least squares regression and spectral reflectance index

The photosynthetic pigment content of forest tree leaves is an important factor affecting photosynthesis in forest trees, and the non-destructive measurement of photosynthetic pigment content is particularly important in current research. The aim of this study was to develop a reflectance index for the determination of photosynthetic pigment content of Catalpa bungei leaves, and in addition to construct a model that can more accurately invert the photosynthetic pigment content. The correlation coefficient method was used to select influential reflectance indices for unitary linear regression model construction; and PLSR was used to accurately describe the photosynthetic pigment content of Catalpa bungei leaves using hyperspectral reflectance and its derived data as input variables. The results showed that the RPD values of Chla and Chl constructed by SR and ND were greater than 2.0, and the RPD value of Chlb was close to 2.0, and the RPD value of Chl/Car was greater than 1.4, and the RPD value of Chla/Chlb was less than 1.4. RLR as a factor to describe the ability of photosynthetic pigment ratio is relatively better than other input variables, Chla concentration and Chlb concentration real inversion to FDRL obviously optimal as input variables, R as the input variables to describe the ability of photosynthetic pigment is relatively better than other input variables. This study constructed an accurate and simplified model for the content of photosynthetic pigments in the leaves of Catalpa bungei, providing technical support for the development of low-cost instruments and the intrinsic correlation between photosynthetic pigments and reflectance.

Genotype-environment interaction in the variability of yield associated indices under stress conditions in sunflower

Abstract The impact of biotic (infestation with the Orobanche cumana) and abiotic stress (drought) factors on the productivity indicators of sunflower hybrids was evaluated in two years, 2020 and 2021, which were significantly different regarding to the weather conditions. The Principal Component Analysis (PCA) was applied on 10 parameters: plant height (PH); leaf number (LN); leaf area (LA); seed yield (SY); leaf area index (LAI); chlorophyll a content (Chla); chlorophyll b content (Chlb); carotenoids content (Car); chlorophyll pigment ratio (Chla/b); total of chlorophyll pigments (Chla+b), that are directly or indirectly associated with the productivity of sunflower hybrids. The first two PCs explained 75 % (drought stress for 2020) and 83 %, respectively (stress caused by broomrape infestation), of the total variance of parameters or hybrids. A higher number of positive correlations were identified between the studied morpho-physiological indices differentiating the hybrids. The SY index correlated with PH, LN, LAI, LA (r = 0.54–0.78) under biotic and abiotic stress. Also, seed yield related with the content of pigments (r = 0.65–0.79) in the case of infested hybrids with broomrape. The infested hybrid H11, in both years, showed the highest values for most of the analyzed indices, indicating a relatively high degree of tolerance to the combined stressors.

Process efficiency and life cycle assessment of novel waste-derived Chl/TiO2 photocatalyst for rhodamine B removal

Visible-light photocatalysis is a promising approach toward cleaner production and environmental impact reduction. Dye sensitization of TiO2 nanoparticles with chlorophyll (Chl) pigments is a potential alternative for the improvement of photocatalysis efficiency but must be modified for higher activity in visible light. Herein, a novel and green Chl/TiO2 photocatalyst was constructed for rhodamine B removal using the TiO2 waste of the gas refinery Clause process, sensitized with extracted chlorophyll from orange tree leaf pigments. The effects of pH, pigment ratios, photocatalyst dosage, and temperature on the Chl/TiO2 photocatalyst performance accompanied by its environmental impacts were investigated. The results indicated that the pristine TiO2 before sensitization could degrade ~30 % of rhodamine B while the photocatalytic activity was enhanced to ~98 % after modification by 0.6 wt% chlorophyll pigments. The optimum conditions were achieved at 25 mg/l Chl/TiO2, pH = 4, and 50 mg/l rhodamine B after 2 h irradiation of visible light (LED lamp 50 W). Recycling studies showed a rhodamine B decolorization of 90 % after 5 cycles and demonstrated that Chl/TiO2 is a promising heterogeneous photocatalyst for the long-term removal of dyes from wastewater. The Chl/TiO2 followed the pseudo-first-order kinetic model and illustrated negative impacts on global warming (6.3 kg CO2) and terrestrial ecotoxicity (10.7 kg 1.4-DCB) from a life cycle assessment (LCA) perspective, originating from electricity consumption and acetone. Summing up, the present study offers a new and eco-efficient photocatalyst to facilitate wastewater treatment in real-world applications and gives perspectives to manage its long-term concern.

Активність фотосинтетичного комплексу бріофітів на трансформованих територіях видобутку вугілля

It was investigated the seasonal dynamic of photosynthetic pigments content in shoots of the Ceratodon purpureus from different positions and local growing on dumps of the Chervonograd mining district. It was established that the quantitative composition of the a & b chlorophyll (chl a and chl b), ratio of the a/b and chlorophylls/carotenoids (Chl/K) in the moss cells changed depending on the position of their local growing on dumps and microclimatic conditions: temperature regime, solar radiation and humidity of the substrate. It was found that in April on open areas where Ceratodon purpureus grew, the content of chlorophyll a in its shoots increased, in July the amount of green pigment (chl a) significantly decreased, and the a/b ratio was lower than in spring. In the summer, content of the carotenoids in the moss cells on the illuminated areas increased, compared to the spring indicators, which prevented possibility of the photooxidation and formation of the free radi­cals under conditions of high insolation and temperature. In autumn, the content of both green pigments and auxiliary pigments in the Ceratodon purpureus shoots, selected from different positions of dumps, mostly decreased, compared to the summer indicators. Chan­ges in quantity and ratio of pigments in different periods of the year on the dumps testified about adaptive character of the mosses photosynthetic system, which contributed to more efficient using of the different intensities solar radiation. Depending on the position on the rock dumps and the degree of their reclamation, the indicators of the chlorophyll index for mosses synusiae were determined. It was found that the indicators of the chlorophyll index depended on the ecological conditions of moss growing in the technogenic environment, the composition of the bryoflora, the amount of green pigments in the photosynthetic organs, and the area of the assimilating surface. For the studied briosynusiae the largest stock of phytomass and the indicators of the chlorophyll index was determined on the dump of the “Nadiya” mine, and the smallest on the dump of the Central Enrichment Factory in the monospecies group Ceratodon purpureus – syn. Were established higher productivity indicators in synusiae, which includes Campylopus introflexus with biomorphic structure of the dense turf, which forms the largest over ground phytomass in growing conditions, compared to other species. The chlorophyll index can serve as an important criterion for assessing the participation of mosses in the production process of plant cover on transformed territories.

Recycled poly(propylene-co-methy1 methacrylate) as printing binder for photoluminescent textiles

Photochromic fabrics change color upon exposure to an external light source. Photoluminescent textiles can undergo phosphorescence or fluorescence emissions. Fluorescent textiles emit light only under an illumination light source, whereas phosphorescent textiles continue emitting light after switching the illumination light source off. Herein, an industrial spinning process was carried out to produce nonwoven fibrous mat from polypropylene plastic waste. Poly(propylene-co-methy1 methacrylate) binder was synthesized via free-radical polymerization of borane-containing polypropylene and methyl methacrylate. A screen-printing composite of rare-earth strontium aluminate nanoparticles and poly(propylene-co-methy1 methacrylate) binder was printed onto recycled nonwoven polypropylene fabrics to introduce photochromic and photoluminescent textiles. Direct application of aqueous pigment-binder composites comprising various ratios of inorganic pigment with outstanding thermal and photostability was deposited onto polypropylene textiles. Screen printing allowed for the application of a consistent photoluminescent layer onto polypropylene surface. The printed nonwoven polypropylene samples had their excitation tracked at 368 nm, and an emission wavelength at 519 nm. The printed cloth with lower phosphor concentrations were found to reversibly emit a green color only under ultraviolet light, demonstrating fluorescence emission. At greater phosphor concentrations, a reversible green emission was monitored under the excitation light source, and greenish-yellow afterglow in the dark. A number of analytical techniques were used to gather microscopic information on the morphology of pigment nanoparticles and printed polypropylene textiles. The phosphor nanoparticles were measured to have diameters of 8–23 nm as reported by transmission electron microscopy (TEM), while X-ray diffraction examination revealed a crystal size of 21 nm. Increasing the pigment ratio enhanced the fabric UV protection, antibacterial activity, and superhydrophobicity. Upon increasing the pigment ratio, the contact and sliding angles were observed to increase in the ranges of 127.5°–160.4° and 11-7°, respectively. The impacts of phosphor ratio on comfort and colorfastness were examined.

Screening Smoke Tree (Cotinus coggygria Scop.) on Osmotic Stress using Polyethylene Glycol 6000 in vitro

Background: Droughts during the growing season are becoming increasingly common due to climate change and global warming. The study’s goal study was to assess the adaptation mechanisms of C. coggygria Scop. under simulated water deficit conditions using indicators characterized changes in the leaf stomatal apparatus and photosynthesizing system. Methods: The influence of osmotic polyethylene glycol 6000 on the research object C. coggygria regenerants was studied in vitro. Such indicators as morphological changes, pigment content, stomatal density and size and stomatal slit size were quantified. Result: Due to the influence of osmotic stress, there was a pigment content increase in the leaf plate on osmotic media. Stomatal density raised by 27.0-29.8% in explant cells cultivated on PEG 4.0-6.0%. Under the osmotic influence, there was a drop in the stomatal cells’ area and shape and the ratio of stomatal length to width in the regenerant leaves decreased from 1.5 to 1.0-1.1. These results indicate the adaptation of C. coggygria regenerants to stress caused by an artificial drought in vitro. The changes’ identification in the stomatal apparatus and the C. coggygria pigment ratio will accelerate the selective screening of drought-resistant plants for use in protective forestry.Background: Droughts during the growing season are becoming increasingly common due to climate change and global warming. The study’s goal study was to assess the adaptation mechanisms of C. coggygria Scop. under simulated water deficit conditions using indicators characterized changes in the leaf stomatal apparatus and photosynthesizing system.

Morphobiological features of generative organs of fertile and sterile table beet plants and their variability as a result of self-pollination (review)

Beet is considered a difficult breeding object due to its biological peculiarities that make it difficult to obtain hybrid seed progeny. In cross-pollinated crops, the maximum hybridization is achieved by using sterile mother plants, which are extremely rare in the nature. Inbreeding is one of the ways to isolate genotypes with cytoplasmic male sterility, which are controlled by recessive alleles of nuclear genes and S-factor of mitochondrial DNA, from a complex heterogeneous population. The main distinguishing features allowing to identify plants with male sterility are the structure and coloring of anthers, and the quality composition of pollen. The diversity of phenotypic manifestation of marker coloration in sterile anthers is determined by the ratio of different pigments. Diversity of pollen grains of fertile and sterile plants is caused by differences in their development at the late stages of androgenesis. The degree of sterilization varies in different genotypes, which is associated with complex regulatory mechanisms of interaction between the genetic apparatus of the nucleus and the cytoplasm. Along with abnormalities of pollen grain micropopulations, self-fertilization results in morphological changes in the structure of inflorescences and number of flower organs, which has a direct impact on the seed productivity of plants. The studies summarized in this publication are relevant and essential for the search of effective ways to control plant development in ontogenesis and universal selection criteria in the process of creating fundamentally new forms of plants, which is especially important for breeding.

Preparation of dual mode encoding photochromic electrospun glass nanofibers for anticounterfeiting applications

Photochromism has shown to be a promising tool for improving the authenticity of commercially available products. Additionally, improving the engineering process of authentication patterns has been crucial to offer mechanically reliable anticounterfeiting nanofibers. Herein, the electrospinning technology was applied to develop mechanically reliable and photoluminescent silicon dioxide-based electrospun glass nanofibers (80–110 nm) embedded with lanthanide-activated aluminate (LA) nanoparticles (NPs; 1–2 nm) for anticounterfeiting purposes. The produced nanocomposite films exhibited photochromism from colorless in visible spectrum to green under ultraviolet irradiation. The nanofibrous film transparency was maintained by presenting the strontium aluminate pigment as nano-scaled particles, which improves its distribution and prevents the formation of aggregates in the electrospun glass nanofibrous bulk. After being excited at 365 nm, the nanofibers made of phosphor@glass (LANPs@GLS) displayed an emission band at 519 nm. Increases in the pigment ratio enhanced the hydrophobicity of the LANPs@GLS nanofibers without altering their intrinsic characteristics. The LANPs@GLS films exhibited fast and reversible photochromism without fatigue when activated by UV light. Transparency and flexibility were shown by the nanofibrous mats. The proposed technique is reliable for making a wide range of anticounterfeiting materials.

An energy-saving glasshouse film reduces seasonal, and cultivar dependent Capsicum yield due to light limited photosynthesis

Glasshouse films can be used to reduce energy costs by limiting non-productive heat-generating radiation, but the impact on yield of greenhouse horticultural crops remains unknown. The effects of energy-saving film ULR-80 (ultra-low-reflectivity film with 80 % light transmission referred to as Smart Glass; SG) designed to block long wavelength light that generates heat also reduced photosynthetically active radiation (PAR) consequently affecting crop morphology, photosynthesis, leaf pigments, and yield of two hydroponically grown capsicum (Capsicum annuum L.) cultivars (Red and Orange). The crops were grown in four high-tech glasshouse bays over two seasons of similar daily light integrals (DLI) during ascending [Autumn Experiment (AE)] and descending [Summer Experiment (SE)] photoperiods. The Red cultivar exhibited higher photosynthetic rates (light saturated - Asat) and yield than the Orange cultivar in control glass but displayed stronger reductions in modelled photosynthetic rates at growth light and yield in SG without changes in photosynthetic capacity. Foliar pigment ratios of chlorophyll a/b and carotenoid:chlorophyll remained unaffected by the SG during both seasons indicating that chloroplast homeostasis was similar between SG and control. The seasonal differences in photosynthetic pigments and xanthophyll de-epoxidation state (DPS) revealed that cultivars were able to sense the SG-altered light environment during the AE, but not SE. The SE correlated with a lower daily light level and a substantial yield reduction of 29 % and 13 % in Red and Orange cultivars, respectively. Thus, SG-induced higher reductions in yield during the SE indicate that SG may be more beneficial for capsicum crops planted during AE.

Different responses of Chlorella vulgaris to silver nanoparticles and silver ions under modulation of nitric oxide.

Silver nanoparticles (Ag-NPs) are widely used in daily life because of their antibacterial properties. A fraction of Ag-NPs are released into the ecosystem during their production and utilization. The toxicity of Ag-NPs has been reported. However, it is still disputed whether the toxicity is mainly due to the released silver ions (Ag+). In addition, few studies have reported the response of algae to metal nanoparticles under modulation of nitric oxide (NO). In this study, Chlorella vulgaris (C. vulgaris) was used as a model organism to study the toxic effects of Ag-NPs and Ag+ released from Ag-NPs on algae under the modulation of NO. The results showed that the biomass inhibition rate of Ag-NPs (44.84%) to C. vulgaris was higher than that of Ag+ (7.84%). Compared with Ag+, Ag-NPs induced more severe damage to photosynthetic pigments, photosynthetic system II (PSII) performance, and lipid peroxidation. More serious damage to cell permeability led to higher internalization of Ag under Ag-NPs stress. Application of exogenous NO reduced the inhibition ratio of photosynthetic pigments and chlorophyll autofluorescence. Further, NO reduced the MDA levels by scavenging reactive oxygen species induced by Ag-NPs. NO modulated the secretion of extracellular polymers and hampered the internalization of Ag. All these results showed that NO alleviates the toxicity of Ag-NPs to C. vulgaris. However, NO did not improve the toxic effects of Ag+. Our results provide new insights into the toxicity mechanism of Ag-NPs to algae modulated by the signal molecule NO.