Photosynthetically Active Research Articles

Comparative Analysis of the Biochemical and Molecular Responses of Nannochloropsis gaditana to Nitrogen and Phosphorus Limitation: Phosphorus Limitation Enhances Carotenogenesis

Nannochloropsis gaditana is well known for its potential for biofuel production due to its high lipid content. Numerous omics and biochemical studies have explored the overall molecular mechanisms underlying the responses of Nannochloropsis sp. to nutrient availability, primarily focusing on lipid metabolism. However, N. gaditana is able to synthesize other valuable products such as carotenoids, including violaxanthin, which has various biological functions and applications. In this study, we comparatively investigated the physiological, biochemical, and molecular responses of N. gaditana to nitrogen and phosphorus limitation, examining biomass production, photosynthetic activity, lipid, chlorophyll, and carotenoids content, and RNA-seq data. Nitrogen limitation decreased photosynthetic activity, chlorophyll content, and biomass production but increased lipid content. Phosphorus limitation substantially increased carotenoids content, with violaxanthin productivity of 10.24 mg/L, 3.38-fold greater than under the control condition, with little effect on biomass production or photosynthetic function. These results were generally consistent with the gene expression pattern observed in transcriptomic analysis. This integrated analysis shows that phosphorus limitation can be an economically competitive solution by enhancing valuable carotenoids while maintaining lipid and biomass production in N. gaditana.

Study of the Biogas Ebullition from Lacustrine Carbonate Enriched and Black Silt Bottom Sediments

The greenhouse effect, which is also promoted by naturally occurring biogas ebullition fluxes (released via bubbles), generated by the decomposition of organic matter in carbonate-enriched and black silt sediments, has been analyzed. This study is based on results obtained using passive gas collectors at different parts of eutrophic Lake Juodis, located in a temperate climate zone in the vicinity of Vilnius (Lithuania). The measured annual biogas (containing about 60% of biomethane) ebullition fluxes from carbonate-enriched sediments and black silt sediments were 16.9–23.0 L/(m2∙y) and 38.5–43.2 L/(m2∙y), respectively. This indicates that the gas fluxes from carbonate sediments were almost twice as low as those from black silt sediments. Oxygen, produced by the photosynthetic activity of green algae in the near-surface water and sediments, helps to retain carbonates in the sediments by preventing their dissolution. In turn, the calcite coating on sediment particles partially preserves organic matter from decomposition, reducing the effective thickness of the sediment layer generating biogas. The characteristic vertical distribution profile of 137Cs activity, with sharp peaks in sediments, suggests that generated biogas bubbles move to the surface of the sediments forming vertical channels by pushing sediment particles asides without noticeably mixing them vertically. This examination showed that factors such as abundance of carbonates in the sediments may result in a significant reduction in biogas generation and emissions from the lake sediments.

The electrochemical ion membrane system (EIMs) enhanced light reactions of photosynthesis with intermittent electrical stimulation.

Despite the widespread application of electrochemical systems in bioproduction, their detailed effects on photosynthetic organisms remain to be explored. In this study, a three-chamber electrochemical ion membrane system (EIMs) was optimized for minimizing carbon resource interference in the cathode chamber, thereby elucidating the role of EIMs in the light reactions of photosynthesis. By applying intermittent electrical stimulation, the photosynthetic activity of microalgae was enhanced, manifesting as the promoted accumulation of intracellular ATP and NADPH, while allowing the collection of hydrogen and oxygen as by-products. These findings suggest that EIMs not only facilitate photosynthesis by enhancing both light and dark reactions but also provide new avenues for improving the efficiency of photosynthetic production and advancing sustainable biotechnological processes.

Investigation of the Variation of Ocean Color and Phytoplankton Functional Types in the Bay of Bengal

The monthly and inter annual variability of Ocean color products and Phytoplankton Functional Types (PFTs) are examined in the Bay of Bengal (BoB) from satellite data (2000-2020). Monthly Chlorophyll-a, Color Dissolved Organic Matter (CDOM), Photosynthetic Active Radiation (PAR) and Suspended Particulate Matter (SPM) data of merged satellites are used in this study. Ten PFTs (Microplankton, Nanoplankton, Picoplankton, Diatoms, Green Algae, Dinoflagellates, Prymnesiophytes, prokaryotes, pico-eukaryotes, Prochlorococcus; 3 phytoplankton size classes (PSC), 7 phytoplankton taxonomic compositions (PTC) are derived from individual monthly Chlorophyll-a. All data are averaged over the BoB region. We have found that the average Chlorophyll-a was decreasing (0.35 mg/m3 to .25 mg/m3) from the year of 2000 to 2020; whereas CDOM shows a sinusoidal relation from the year of 2000 to 2020; PAR has showed a decrease until 2014 then increase; SPM shows a rapid exponentially increasing trend from 2013. The highest Chlorophyll-a is found in the monsoon season (August) due to the high load of river discharge, cloudy environment, and associated favorable conditions; the lowest Chlorophyll-a is found in summer (April) due to the increased sunlight and PAR. Diatoms are the most dominant group in the BoB, which is going to be replaced by smaller planktons like Prochlorococcus species. Chlorophyll-a has a strong relationship with CDOM whereas PAR has a negative relationship with Chlorophyll-a and CDOM. Prokaryotes and Prochlorococcus have showed negative correlation with other functional groups. The Dhaka University Journal of Earth and Environmental Sciences, Vol. 13(1), 2024, P 31-45

Response of Morphological Plasticity of Quercus variabilis Seedlings to Different Light Quality

This experiment explores the regulatory mechanisms of various light qualities on the phenotypic plasticity of Quercus variabilis seedlings during their growth. The light conditions included blue light (BL), red light (RL), far-red light (FrL), a blend of RL and FrL with a ratio of 1:1 (RFr1:1L), and a blend of RL and FrL with a ratio of 1:2 (RFr1:2L), alongside a broad-spectrum white light (WL) as the control. Each treatment was maintained at a consistent photosynthetic photon flux density of 400 µmol·m−2·s−1. Results indicate significant morphological variations in Q. variabilis seedlings under different light qualities. Compared to white light treatment, all light quality treatments enhance seedling height, with the FrL treatment exhibiting the most pronounced effect. Seedling ground diameter elongation is stimulated by all light quality treatments, except for the BL treatment. Although the BL treatment promotes leaf morphology in Q. variabilis seedlings, it inhibits root growth, leading to reduced biomass accumulation and a lower root-to-shoot ratio. FrL can mitigate the effects of RL. Under the FrL treatment, Q. variabilis seedlings exhibit a greater increase in plant height and a higher height-to-diameter ratio. While the leaf morphology of RFr1:1L treatment does not show significant advantages, it demonstrates substantial root growth, resulting in the highest biomass accumulation. Quercus variabilis displays the strongest morphological plasticity in its root system, showing greater sensitivity to variations in light quality compared to leaf morphology and biomass accumulation. Strategically optimizing light spectrum and wavelength can significantly boost economic yields and improve the quality of forestry products.

Subcellular ToF-SIMS Imaging of the Snow Alga Sanguina nivaloides by Combining High Mass and High Lateral Resolution Acquisitions.

Time-of-flight secondary ion mass spectrometry (ToF-SIMS) imaging has demonstrated great potential for metabolic imaging; however, achieving sufficiently high lateral and mass resolution to reach the organelle scale remains challenging. To address this, we have developed an approach that combines imaging acquisitions close to the highest lateral resolution (<150 nm) and mass resolution (9,000) reachable by ToF-SIMS. The data were then merged and processed using multivariate analysis (MVA), providing the identification and annotation of 85% of the main contributors to the multivariate analysis components at high lateral resolution. Insights into the electron microscopy sample preparation were provided, especially as we revealed that at least three different osmium-containing complexes can be found depending on the specific chemical environment of organelles. In cells of the snow alga Sanguina nivaloides, living in a natural environment limited in nutrients such as phosphorus (P), we mapped elements and molecules within their subcellular context, allowing for the molecular fingerprinting of organelles at a resolution of ∼150 nm, as confirmed by correlative electron microscopy. It was thus possible to highlight that S. nivaloides likely absorbed selectively some inorganic P forms provided by P-rich dust deposited on the snow surface. S. nivaloides cells could maintain phosphorylations in the stroma of the chloroplast, consistently with the preservation of photosynthetic activity. The presented method can thus overcome the current limitations of ToF-SIMS for subcellular imaging and contributes to the understanding of key questions, such as P homeostasis and other cell physiological processes.

Genetic Analysis of the Peach SnRK1β3 Subunit and Its Function in Transgenic Tomato Plants

Background/Objectives: The sucrose non-fermentation-related kinase 1 (SnRK1) protein complex in plants plays an important role in energy metabolism, anabolism, growth, and stress resistance. SnRK1 is a heterotrimeric complex. The SnRK1 complex is mainly composed of α, β, βγ, and γ subunits. Studies on plant SnRK1 have primarily focused on the functional α subunit, with the β regulatory subunit remaining relatively unexplored. The present study aimed to elucidate the evolutionary relationship, structural prediction, and interaction with the core α subunit of peach SnRK1β3 (PpSnRK1) subunit. Methods: Bioinformatics analysis of PpSnRK1 was performed through software and website. We produced transgenic tomato plants overexpressing PpSnRK1 (OEPpSnRK1). Transcriptome analysis was performed on OEPpSnRK1 tomatoes. We mainly tested the growth index and drought resistance of transgenic tomato plants. Results: The results showed that PpSnRK1 has a 354 bp encoded protein sequence (cds), which is mainly located in the nucleus and cell membrane. Phylogenetic tree analysis showed that PpSnRK1β3 has similar domains to other woody plants. Transcriptome analysis of OEPpSnRK1β3 showed that PpSnRK1β3 is widely involved in biosynthetic and metabolic processes. Functional analyses of these transgenic plants revealed prolonged growth periods, enhanced growth potential, improved photosynthetic activity, and superior drought stress tolerance. Conclusions: The study findings provide insight into the function of the PpSnRK1 subunit and its potential role in regulating plant growth and drought responses. This comprehensive analysis of PpSnRK1 will contribute to further enhancing our understanding of the plant SnRK1 protein complex.

Morphological and physiological responses of Momordica charantia to heavy metals and nutrient toxicity in contaminated water

This study investigates the impact of industrial wastewater from leather, household, and marble sources on the growth, physiological traits, and biochemical responses of Momordica charantia (bitter melon). Industrial activities often lead to the release of contaminated effluents, which can significantly affect plant health and agricultural productivity. Water analysis revealed that leather effluent contained high concentrations of heavy metals, including cadmium (2.67 mg/L), lead (1.95 mg/L), and nickel (1.02 mg/L), all of which exceeded the recommended safety limits for irrigation. Seed germination was significantly reduced, with only 45% germination in seeds irrigated with leather effluent, compared to 90% in the control group. Similarly, in plants treated with leather wastewater, shoot length, and root length were reduced by 38% and 42%. Chlorophyll content showed a marked decline, with chlorophyll “a” reduced by 25% and chlorophyll “b” by 30% in wastewater-treated plants, indicating impaired photosynthetic activity. Antioxidant enzyme activity, including catalase and superoxide dismutase, increased by up to 40%, reflecting a stress response to heavy metal toxicity. These findings highlight that industrial wastewater severely disrupts plant metabolic processes, leading to stunted growth and physiological stress. To safeguard crop productivity and food security, stringent wastewater treatment protocols must be implemented to mitigate environmental contamination. Future research should focus on developing advanced remediation techniques and sustainable wastewater management practices to reduce heavy metal toxicity and enhance soil health.

The morphological variability and photosynthetic activity of the epigeic mosses in the forest ecosystems depending on the ecological locality conditions

The peculiarities of morphological variability and photosynthetic activity of the dominant epigeic mosses Polytrichastrum formosum, Plagiomnium affine and Atrichum undulatum depending on microclimatic conditions and the degree of anthropogenic changes in forest ecosystems were investigated. The morphological variability of mossy turfs in different ecological conditions of forest ecosystems was established, in particular, the influence of the level of humidity and the intensity of light on the morphometric parameters of mosses was revealed. The shoots and leaves of the studied mosses from the felling area were smaller and the density of turfs was higher compared to other localities. It was determined that a decrease in shoot height, leaf size, increase in leafiness and shoot density contributed to the preservation of water balance within the moss turf and the upper layer of the substrate. The dependence of the photosynthetic intensity of the leaves of dominant mosses on the moisture content of their turf and topsoil in the experimental plots of forest ecosystems was revealed. Changes in the functioning of the pigment system not only determined the photosynthetic activity of mosses in different localities, but also served as markers of their resistance to environmental conditions. The lowest intensity of CO2 assimilation was determined in the gametophyte of mosses in areas with recreational load. Probably, higher light intensity led to a violation of the water and temperature regime of plants, and thus to a decrease in their photosynthetic activity.

Mitigating salt stress in Zea mays: Harnessing Serratia nematodiphila-biochar-based seed coating for plant growth promotion and rhizosphere microecology regulation

Salt stress poses a significant challenge in contemporary agricultural practices. In response, using plant growth-promoting bacteria (PGPB) in conjunction with biochar coatings has emerged as an innovative biological strategy to mitigate salt stress in crops. Through a dual screening process based on gradient salt concentration and plant growth-promoting performance, a highly salt-tolerant PGPB, Serratia nematodiphila, was identified in this study. And a seed-coating formulation incorporating S. nematodiphila was developed using biochar as a carrier. With the help of potting experiments, this paper investigated the impact of this S. nematodiphila-biochar-based seed coating on Zea mays under salt stress, while also analyzing functional alterations in the core microbial community. These findings indicate that the S. nematodiphila-biochar-based seed coating selectively enriched beneficial microbial populations, such as Proteobacteria, Gammaproteobacteria, Verrucomicrobiae, and Bacteroidia, fostering a symbiotic association with the Z. mays root system. These beneficial consortia facilitated the accumulation of osmotic solutes, including soluble sugars, soluble proteins, and proline, thereby modulating leaf photosynthetic activity and alleviating salt stress (sodium and potassium homeostasis) in Z. mays. This investigation provides refined technical approaches for alleviating salt stress in Z. mays, contributing to developing sustainable agricultural practices.

The interactive effects between far-red light and temperature on lettuce growth and morphology diminish at high light intensity.

Phytochromes (PHYs) play a dual role in sensing light spectral quality and temperature. PHYs can interconvert between the active Pfr form and inactive Pr form upon absorption of red (R) and far-red (FR) light (Photoconversion). In addition, active Pfr can be converted to inactive Pr in a temperature-dependent manner (Thermal Reversion). Recent studies have shown that FR light and temperature can interactively affect plant growth and morphology through co-regulating phytochrome activities. These studies were primarily conducted under relatively low light intensities. As light intensity increases, the impact of thermal reversion on phytochrome dynamics decreases. However, the light intensity dependency of the interactive effects between FR light and temperature on plant growth and morphology has not been characterized. In this study, lettuce (Lactuca sativa L.) 'Rex' was grown under two total photon flux densities (TPFD; 400-800 nm) (150 and 300 μmol m-2 s-1) x three temperatures (20, 24, and 28°C) x two light spectra (0 and 20% of FR light in TPFD). Our results showed that the effects of FR light on leaf, stem, and root elongation, leaf number, and leaf expansion were dependent on temperature at lower TPFD. However, the magnitude of the interactive effects between FR light and temperature on plant morphology decreased at higher TPFD. Particularly, at a lower TPFD, FR light stimulated leaf expansion and canopy photon capture only under a cooler temperature of 20°C. However, at a higher TPFD, FR light consistently increased total leaf area across all three temperatures. Plant biomass was more strongly correlated with the total number of photons intercepted by the leaves than with the photosynthetic activities of individual leaves. FR light decreased the contents of chlorophylls, carotenoids, flavonoids, and phenolics, as well as the total antioxidant capacity. In contrast, warmer temperatures and high light intensity increased the values of these parameters. We concluded that the interactive effects between FR light and temperature on plant growth and morphology diminished as total light intensity increased. Additionally, the combination of high light intensity, warm temperature, and FR light resulted in the highest crop yield and antioxidant capacity in lettuce.

Strawberry Grown in an Indoor Vertical Farm Responds to Increased Photosynthetic Photon Flux Density When Calcium Is Supplied at Higher Concentrations

Indoor vertical farms can optimize light, temperature, humidity, and nutrient use, thus potentially maximizing crop growth and yield. However, the reported potential for enhanced crop growth and yield within these systems needs to be tempered against the understanding of the effects of this “forced growth”/optimal growth environment on “actual” plant performance to fully reap the benefits of these innovative vertical farming systems. We investigated the effect of calcium (Ca) on the production of strawberries in an indoor vertical farm system with varying photosynthetic photon flux density (PPFD). Fruit yield of plants fed with high Ca (9 meq·L−1) increased by 42.3% when the PPFD was 422 µmol·m−2·s−1; however, a subsequent increase to 572 µmol·m−2·s−1 resulted in a decline in fruit production. Plants treated with low Ca (5 meq·L−1) had a reduced yield and demonstrated no response to the PPFD. The observed increase in yield was associated with increased fruit production and total soluble solids. Plants exhibited 21.5% and 57.8% increases in the total dry weight when exposed to 422 and 572 µmol·m−2·s−1, respectively; however, Ca did not have any impact on this response. Independent of the Ca concentration, the photosynthesis rate increased by 16.1% and 22.2% when the PPFD increased to 422 and 572 µmol·m−2·s−1, respectively; however, the highest photosynthesis rate was recorded with 422 µmol·m−2·s−1 when the Ca level was 9 meq·L−1. High Ca-fed plants exhibited a reduction in Ca (−17.1%) content in their fruits when exposed to 572 µmol·m−2·s−1, which was likely caused by a dilution effect attributable to increased fruit biomass. In contrast, shoot Ca increased when plants were given high Ca when the PPFDs were 422 and 572 µmol·m−2·s−1. The Ca concentration in shoots correlated with the increasing yield, and a higher Ca concentration was associated with the increasing transpiration rate and stomatic conductance. Shoot phosphorus declined when plants were exposed to increased PPFD, and phosphorus was lower when plants were provided with 9 meq·L−1 of Ca; however, plants watered with low Ca solutions had more potassium. The shoot nitrogen content and micronutrient contents were unchanged regardless of the variations in PPFD or Ca. In summary, the favorable conditions for the cultivation of strawberry under controlled environments resulted in greater growth and fruit yield as long as Ca was provided at higher concentrations in the irrigation solutions (from 5 to 9 meq·L−1). We suggest that the higher demand of Ca that is necessary to satisfy the enhanced plant development observed in indoor farming systems may be connected to the role of Ca in the formation of new tissues, cell walls, and cell membranes.

Differential Responses of Sap Flow to Environmental Factors Under Contrasting Rainfall Amounts During the Rainy Season in a Boreal Birch Forest

ABSTRACTSap flow dynamics are critical for understanding how vegetation consumes water and adapts to environmental stress. The response of sap flow in boreal birch secondary forests to rainfall variations during the rainy season, however, has been inadequately explored. Our study indicated that photosynthetically active radiation (PAR) and vapour pressure deficit (VPD) are the primary drivers of sap flow density in birch trees across different diameter classes (Fds: small trees, Fdm: medium‐sized trees, Fdl: large trees). Soil water content (SWC) significantly reduces sap flow when it falls below the 0.18 cm3/cm3. Sap flow density increased with PAR and initially with VPD but plateaued at higher VPD levels due to saturation. A hierarchy of sap flow density was observed, with Fdl &gt; Fdm &gt; Fds, each responding differently to PAR, VPD and SWC. With decreasing rainfall across rainy seasons, the influence of PAR on Fds and Fdm weakened, while the influence of VPD strengthened. For Fdl, the impact of VPD peaked and then declined, while the influence of PAR showed an inverse pattern. In the dry season, Fdl was primarily driven by PAR and influenced by VPD and SWC, whereas Fds was mainly controlled by VPD, with minimal effects from PAR and SWC. The response of Fdm to SWC was similar to that of Fdl, but it mirrored the response of Fds to PAR and VPD. These findings suggest that sap flow in boreal birch forests may become increasingly susceptible to SWC stress as global climate change intensifies.

Additional far-red increases fruit yield of greenhouse sweet pepper mainly through enhancing plant source strength

Supplementary lighting is necessary for year-round greenhouse production of fruit vegetables in high-latitude regions. Far-red (FR) radiation can influence plant photomorphogenesis as well as photosynthesis. We aimed to identify the effects of supplementary FR on fruit set and yield of sweet pepper, and its underlying mechanisms via a yield component analysis. A 24-week greenhouse experiment was conducted with cultivars 'Gialte' and 'Margrethe', where FR was added to 190 μmol·m−2·s−1 of white supplementary light in four treatments: 0, 50 or 100 μmol·m−2·s−1 FR throughout the whole generative growth phase (since 8 weeks after transplanting), or 100 μmol·m−2·s−1 FR for only four weeks (12 to 16 weeks after transplanting). Fruit yield increased linearly with the cumulative amount of FR provided in supplementary light. The increased fruit dry weight with additional FR was mainly associated with an increased plant dry weight, accompanied by a marginal increase in the fraction of dry matter partitioned to fruits. The increase in plant dry weight resulted from an increased light use efficiency (plant dry weight per unit of supplementary photosynthetic active radiation (PAR) incident on top of the canopy) and an increased incident PAR (due to taller plants closer to the lamps). However, additional FR reduced radiation use efficiency (plant dry weight per unit of supplementary PAR plus FR incident on top of the canopy), indicating that additional FR was used less efficiently than PAR for biomass production. Additional FR enhanced fruit set percentage and fruit set fluctuations over time, where both long-term and short-term FR application elevated the subsequent fruit set peak after the start of FR application. Without additional FR, 17% fruits in 'Gialte' and 25% in 'Margrethe' showed medium or severe cracking. Additional FR substantially reduced this percentage to 8% in both cultivars. We conclude that additional FR improves sweet pepper fruit set and yield in greenhouses, mainly by enhancing plant source strength.

Environmental Influences on Evapotranspiration in Wheat-Maize Rotation Systems under Diverse Hydrological Regimes in the Guanzhong Plain, China

Evapotranspiration (ET) is a crucial hydrological process in terrestrial and agricultural ecosystems, and is a key factor driving climate change dynamics. Understanding the variability of ET and how it responds to controlling factors helps describe the impact of environmental changes on agricultural ecosystems. This study analyzes long-term continuous measurements from an Eddy Covariance (EC) system in wheat-maize rotation fields in the Guanzhong Plain in China. Using structural equation modeling (SEM), we investigated the regulatory roles of environmental and biological factors on ET, and the mechanisms controlling ET for summer maize and winter wheat under varying hydrological and climatic conditions. The results indicate that the eight-year average ET during the summer maize season ranged from 259 to 348mm; during the winter wheat season, it ranged from 369 to 513mm. The adjusted SEM explained 64% of the variation in daily ET during the summer maize season and 80% during the winter wheat season. Photosynthetically active radiation (PAR) was the primary controlling factor for both seasons, with air temperature (Tair) also playing a significant role. Leaf area index (LAI) was an important mediator for ET, and had a greater effect during the winter wheat season than during the summer maize season. Vapor pressure deficit (VPD) and soil water content (SWC) had a more significant impact on ET during the summer maize season than during the winter wheat season. The ET response to environmental factors varied significantly under different hydrological and climatic conditions. Specifically, the total effect of PAR on ET increased with increased moisture availability and decreased temperature; the trend was opposite for Tair. This indicates that high temperatures and drought conditions may increase the sensitivity of ET to temperature changes, and decrease the sensitivity of ET to radiation changes. This study explains the variability of evapotranspiration in agricultural ecosystems and associated controlling factors, providing important insights about how agricultural evapotranspiration responds to vegetation phenology under future climate change scenarios. These investigations help optimize water resource utilization and allocation in agricultural fields.

Mitigating salt stress in “Friariello Napoletano” (Brassica rapa subsp. sylvestris L. Janch. var. esculenta Hort.): The potential of biochar for sustainable agriculture

The agricultural sector is therefore called upon to seek efficient and sustainable strategies to improve plant resilience and tolerance to sub-optimal growth conditions. In many coastal areas of the Mediterranean, saline stress causes serious problems to vegetable crops. In this scenario, the use of upgraded agrochemicals such as plant biostimulants, biochar and plant nutrition regulators could be beneficial. The aim of the study was to evaluate the effects of amending the soil with different concentrations of poplar-derived biochar (0 %, 1 % and 2 % by volume), on the productive and qualitative response of an ecotype of “Friariello Napoletano” (Brassica rapa subsp. sylvestris L. Janch. var. esculenta Hort.) under different levels of saline irrigation (0, 30, 60 and 120 mM NaCl, giving an electrical conductivity values of 0.05, 2.09, 6.09 and 9.70 dS m–1). The experiment was conducted in an unheated greenhouse, using pot plants grown in soil with a randomized complete-block experimental design arranged in a 4 × 3 factorial scheme with three replications. Productive and physiological results (ACO2, gs, E, SPAD index) highlighted a highly glycophytic response of Friariello. Biochar integration, besides increasing total production and glucosinolate content, led to a significant reduction in toxic ion content (Na+and Cl−) under saline conditions compared to control plants. Regardless of salinity effect, the application of biochar resulted in an increase in fresh yield and photosynthetic activity (ACO2) of 12.8 % and 29.3 % respectively. The promising results underscore the potential role of biochar as a sustainable strategy for mitigating salt stress in Friariello Napoletano and potentially other vegetable crops in salt-affected regions. However, it needs to be clarified which adaptive mechanisms triggered by biochar improves production performance even and especially under sub-optimal growing conditions.

Investigating physiological responses and fine particulate matter retention of urban trees in Budapest

The urban environment is posing substantial challenges to both human well-being and the growth of plantations. Deploying advanced urban trees that effectively interact with atmospheric pollution will be a crucial step in urban planning. However, there is a paucity of knowledge in Hungary regarding these aspects. We studied the photosynthesis activities of three commonly planted trees (Acer platanoides, Fraxinus excelsior, and Tilia tomentosa) from two locations in Budapest, as well as their potential of capturing fine particulate matter on leaf surfaces. Our results reveal that T. tomentosa has developed a denser canopy and better photosynthetic activities, hence enhancing its adaptation to the urban environment in Budapest. F. excelsior showed a higher amount of fine PM wash-off, as it has a smoother leaf surface and was subjected to influences from wind speed and precipitation, making the captured particles more easily dislodged. Whereas fine PM concentration of A. platanoides and T. tomentosa were influenced by ambient PM10 and PM2.5, which might retain on their rough and hairy leaf surfaces. Approximately 38.17 tons of fine PM could be retained on urban greenery of Budapest at any given moment, highlighting the significant ecological and economic benefits of urban greenery. However, more accurate and long-term modeling is needed to develop a sustainable strategy for maximizing these benefits.

A Machine Learning Approach to Produce a Continuous Solar‐Induced Chlorophyll Fluorescence Over the Arctic Ocean

AbstractPhytoplankton primary production is a crucial component of Arctic Ocean (AO) biogeochemistry, playing a pivotal role in carbon cycling by supporting higher trophic levels and removing atmospheric carbon dioxide. The advent of satellite observations measuring chlorophyll a concentration (Chl_a) has provided unprecedented insights into the distribution of AO phytoplankton, enhancing our ability to assess oceanic net primary production (NPP). However, the optical properties of AO waters differ significantly from those of the lower‐latitude waters, complicating remotely sensed Chl_a retrievals. To mitigate these deficiencies, solar‐induced chlorophyll fluorescence (SIF) has emerged as a valuable tool for gaining physiological insights into the direct photosynthetic processes of the AO. However, the temporal coverage of satellite SIF data makes long‐term analysis of Chl_a photosynthetic activity challenging. In this study, we leverage satellite‐based SIF measurements from 2018 to 2021 to assess their correlation with a set of predictive factors influencing phytoplankton photosynthesis. Generally, observed SIF over the AO showed a higher correlation with normalized fluorescence line height (NFLH) compared to Chl_a. We extended the temporal coverage of the original SIF data to encompass the period from 2004 to 2020. The extended record revealed noticeable differences between SIF, and satellite‐based Chl_a, and NFLH observations. Our novel data set offers a pathway forward to monitor the physiological interactions of phytoplankton with climate changes, promising to significantly improve our understanding of Arctic waters productivity. The application of this data is expected to provide new insights into how phytoplankton respond to environmental shifts, contributing to a more nuanced understanding of their role in high‐latitude marine ecosystems.

Role of LED (Light Emitting Diode) Light Illumination on the Growth of Plants in Greenhouse Farming-Hydroponics: IOT Technology

This review paper of literature highlights role of Light Emitting Diode (LED) on the growth of plants under controlled conditions of greenhouse farming particularly hydroponics. “Internet of Things (IOT)” is a system of interconnected computing devices, sensors, objects, microcontrollers, and cloud servers that can transmit data across a network and control other devices remotely without human intervention. Light Emitting Diode (LED) is a more efficient, versatile, lasts longer, highly energy-efficient, directional, narrow light spectrum, low power consumption, and little heat production. Common LED colors include amber, red, green, and blue. Hydroponic grow lights are designed to mimic the natural light that plants need for photosynthesis. Plants can only use the spectrum of visible light to produce photosynthesis, and this narrow spectrum (400 to 700 nanometer) is recognized as the Photosynthetically Active Radiation (PAR). The development and growth of diverse plant species can be influenced differently by a variety of colored LED lights. LED illumination provides an efficient way to improve yield and modify plant properties. Therefore, LED systems plays an important role in controlling morphological, genetic, physiological, chemical properties, increasing the synthesis of a variety of beneficial secondary metabolites, and optobiological interactions of plants in greenhouse farming. In general, red and blue light is essential for maximizing the photosynthesis process due to their strong absorption by the plant chlorophyll molecules. LED illumination sources are increasingly being utilized to enhance the growth rate of vegetables and herbs cultivated in greenhouses worldwide. LED illumination spectrum manipulation could enable significant morphological adaptations, and identification of the wavelength ranges is required to increase the plant photosynthesis process.

Comparative study of the effect of moderate and strong sodium chloride salinization on growth and photosynthetic apparatus of cultivated cereals

In a controlled environment, the effect of moderate (100 mM) and strong (200 mM) sodium chloride salinity on seed germination, seedling growth and the state of the photosynthetic apparatus (PSA) of barley (Hordeum vulgare L.) varieties Nur and wheat (Triticum aestivum L.) varieties Zlata was studied. It was found that with moderate salinization, the seeds of both species successfully germinated, but the growth of shoots and the accumulation of aboveground biomass were inhibited, which was partly due to a slowdown in the rate of photosynthesis. With strong salinity, distinct interspecific differences were observed in the response of plants. In particular, the number of germinated seeds decreased in barley, while in wheat it remained at the control level. In barley, shoot growth was inhibited to a greater extent, whereas in wheat, the accumulation of aboveground biomass was. The content of pigments in barley plants decreased, and the content of wheat increased. At the same time, stomatal conductivity decreased in both species and the rate of photosynthesis slowed down. It is concluded that based on the energy of germination and germination of seeds, it is possible to determine the salt resistance of species only to a high level of salinity (200 mM NaCl). Morphometric indicators of shoot growth make it possible to assess the resistance of plants to salinity already at lower salt concentrations (100 mM NaCl). For a more accurate comparative assessment of the salt resistance of species (varieties, varietals, genotypes) of cereals, not one, but several indicators should be used, reflecting not only the growth potential of plants, but also photosynthetic activity.