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We describe a procedure for the calculation of quasi-diabatic states within the recently introduced DFT/MRCI(2) framework [S. P. Neville and M. S. Schuurman, J. Chem. Phys. 157, 164103 (2022)]. Based on an effective Hamiltonian formalism, the proposed procedure, which we term QD-DFT/MRCI(2), has the advantageous characteristics of being simultaneously highly efficient and effectively black box in nature while directly yielding both quasi-diabatic potentials and wave functions of high quality. The accuracy and efficiency of the QD-DFT/MRCI(2) formalism are demonstrated via the simulation of the vibronic absorption spectra of furan and chlorophyll a. [ABSTRACT FROM AUTHOR]

Low iron (Fe) bioavailability can limit the biosynthesis of Fe-containing proteins, which are especially abundant in photosynthetic organisms, thus negatively affecting global primary productivity. Understanding cellular coping mechanisms under Fe limitation is therefore of great interest. We surveyed the temporal responses of Chlamydomonas (Chlamydomonas reinhardtii) cells transitioning from an Fe-rich to an Fe-free medium to document their short and long-term adjustments. While slower growth, chlorosis and lower photosynthetic parameters are evident only after one or more days in Fe-free medium, the abundance of some transcripts, such as those for genes encoding transporters and enzymes involved in Fe assimilation, change within minutes, before changes in intracellular Fe content are noticeable, suggestive of a sensitive mechanism for sensing Fe. Promoter reporter constructs indicate a transcriptional component to this immediate primary response. With acetate provided as a source of reduced carbon, transcripts encoding respiratory components are maintained relative to transcripts encoding components of photosynthesis and tetrapyrrole biosynthesis, indicating metabolic prioritization of respiration over photosynthesis. In contrast to the loss of chlorophyll, carotenoid content is maintained under Fe limitation despite a decrease in the transcripts for carotenoid biosynthesis genes, indicating carotenoid stability. These changes occur more slowly, only after the intracellular Fe quota responds, indicating a phased response in Chlamydomonas, involving both primary and secondary responses during acclimation to poor Fe nutrition.

Soil salinity is a major nutritional challenge with poor agriculture production characterized by high sodium (Na+) ions in the soil. Zinc oxide nanoparticles (ZnO NPs) and biochar have received attention as a sustainable strategy to reduce biotic and abiotic stress. However, there is a lack of information regarding the incorporation of ZnO NPs with biochar to ameliorate the salinity stress (0, 50,100 mM). Therefore, the current study aimed to investigate the potentials of ZnO NPs application (priming and foliar) alone and with a combination of biochar on the growth and nutrient availability of spinach plants under salinity stress. Results demonstrated that salinity stress at a higher rate (100 mM) showed maximum growth retardation by inducing oxidative stress, resulted in reduced photosynthetic rate and nutrient availability. ZnO NPs (priming and foliar) alone enhanced growth, chlorophyll contents and gas exchange parameters by improving the antioxidant enzymes activity of spinach under salinity stress. While, a significant and more pronounced effect was observed at combined treatments of ZnO NPs with biochar amendment. More importantly, ZnO NPs foliar application with biochar significantly reduced the Na+ contents in root 57.69%, and leaves 61.27% of spinach as compared to the respective control. Furthermore, higher nutrient contents were also found at the combined treatment of ZnO NPs foliar application with biochar. Overall, ZnO NPs combined application with biochar proved to be an efficient and sustainable strategy to alleviate salinity stress and improve crop nutritional quality under salinity stress. We inferred that ZnO NPs foliar application with a combination of biochar is more effectual in improving crop nutritional status and salinity mitigation than priming treatments with a combination of biochar.

Natural photosystems couple light harvesting to charge separation using a 'special pair' of chlorophyll molecules that accepts excitation energy from the antenna and initiates an electron-transfer cascade. To investigate the photophysics of special pairs independently of the complexities of native photosynthetic proteins, and as a first step toward creating synthetic photosystems for new energy conversion technologies, we designed C2-symmetric proteins that hold two chlorophyll molecules in closely juxtaposed arrangements. X-ray crystallography confirmed that one designed protein binds two chlorophylls in the same orientation as native special pairs, whereas a second designed protein positions them in a previously unseen geometry. Spectroscopy revealed that the chlorophylls are excitonically coupled, and fluorescence lifetime imaging demonstrated energy transfer. The cryo-electron microscopy structure of a designed 24-chlorophyll octahedral nanocage with a special pair on each edge closely matched the design model. The results suggest that the de novo design of artificial photosynthetic systems is within reach of current computational methods.

A central goal of photoprotective energy dissipation processes is the regulation of singlet oxygen (1O2*) and reactive oxygen species in the photosynthetic apparatus. Despite the involvement of 1O2* in photodamage and cell signaling, few studies directly correlate 1O2* formation to nonphotochemical quenching (NPQ) or lack thereof. Here, we combine spin-trapping electron paramagnetic resonance (EPR) and time-resolved fluorescence spectroscopies to track in real time the involvement of 1O2* during photoprotection in plant thylakoid membranes. The EPR spin-trapping method for detection of 1O2* was first optimized for photosensitization in dye-based chemical systems and then used to establish methods for monitoring the temporal dynamics of 1O2* in chlorophyll-containing photosynthetic membranes. We find that the apparent 1O2* concentration in membranes changes throughout a 1 h period of continuous illumination. During an initial response to high light intensity, the concentration of 1O2* decreased in parallel with a decrease in the chlorophyll fluorescence lifetime via NPQ. Treatment of membranes with nigericin, an uncoupler of the transmembrane proton gradient, delayed the activation of NPQ and the associated quenching of 1O2* during high light. Upon saturation of NPQ, the concentration of 1O2* increased in both untreated and nigericin-treated membranes, reflecting the utility of excess energy dissipation in mitigating photooxidative stress in the short term (i.e., the initial ∼10 min of high light).

Blood cockle sampling and water quality monitoring were conducted monthly between September 2011 and June 2013 at four blood cockle aquaculture farms situated along the Selangor coast, of Malaysia. Histological observations of the gonads were performed to identify male and female blood cockles. The maturation of gonadal tissue was evaluated, and the relationship between the maturation status of blood cockles and water quality factors, such as salinity and chlorophyll a concentration, was examined at each station. Mature and spawning male cockles were present year-round at all stations except at Station C, where males were more susceptible to the influence of the estuary. Females exhibited a distinct seasonal change in gonadal tissue compared with males, with a higher proportion of spent-stage individuals during the dry season. In addition, the number of immature individuals, for which it was difficult to distinguish between males and females, increased during that period. These results showed that spawning activity on the Selangor coast is more prominent during the rainy season and less pronounced during the dry season. The relationship between salinity, chlorophyll a concentration, and the gonadal tissue maturation stage of the cockle was identified. These findings reveal that sexual maturation progressed in brackish water with a salinity of approximately 28 in both males and females. As salinity decreased to less than 25, the proportion of immature and spent-stage individuals that released sperm or eggs increased. Additionally, immature individuals' percentage increased when chlorophyll a concentration was low ( KEY WORDS: sexual maturation, blood cockle, Tegillarca granosa, Selangor, Malaysia, INTRODUCTION Also known as Anadara granosa (Linnaeus, 1758), Tegillarca granosa (Linnaeus, 1758) is a blood cockle. It is morphologically defined by approximately 18 ribs and numerous nodules on the shell [...]

Pheophytin a and chlorophyll a have been investigated by electrospray mass spectrometry in the positive and negative modes, in view of the importance of the knowledge of their properties in photosynthesis. Pheophytin and chlorophyll are both observed intensely in the protonated mode, and their main fragmentation route is the loss of their phytyl chain. Pheophytin is observed intact in the negative mode, while under collisions, it is primarily cleaved beyond the phytyl chain and loses the attaching propionate group. Chlorophyll is not detected in normal conditions in the negative mode, but addition of methanol solvent molecule is detected. Fragmentation of this adduct primarily forms a product (−30 amu) that dissociates into dephytyllated deprotonated chlorophyll. Semi-empirical molecular dynamics calculations show that the phytyl chain is unfolded from the chlorin cycle in pheophytin a and folded in chlorophyll a. Density functional theory calculations have been conducted to locate the charges on protonated and deprotonated pheophytin a and chlorophyll a and have found the major location sites that are notably more stable in energy by more than 0.5 eV than the others. The deprotonation site is found identical for pheophytin a and the chlorophyll a-methanol adduct. This is in line with experiment and calculation locating the addition of methanol on a double bond of deprotonated chlorophyll a. [ABSTRACT FROM AUTHOR]

Chlorophyll c is a key photosynthetic pigment that has been used historically to classify eukaryotic algae. Despite its importance in global photosynthetic productivity, the pathway for its biosynthesis has remained elusive. Here we define the CHLOROPHYLL C SYNTHASE (CHLCS) discovered through investigation of a dinoflagellate mutant deficient in chlorophyll c. CHLCSs are proteins with chlorophyll a/b binding and 2-oxoglutarate-Fe(II) dioxygenase (2OGD) domains found in peridinin-containing dinoflagellates; other chlorophyll c-containing algae utilize enzymes with only the 2OGD domain or an unknown synthase to produce chlorophyll c. 2OGD-containing synthases across dinoflagellate, diatom, cryptophyte, and haptophyte lineages form a monophyletic group, 8 members of which were also shown to produce chlorophyll c. Chlorophyll c1 to c2 ratios in marine algae are dictated in part by chlorophyll c synthases. CHLCS heterologously expressed in planta results in the accumulation of chlorophyll c1 and c2, demonstrating a path to augment plant pigment composition with algal counterparts.

WHOI assistant scientist Tom Bell stands with his drone on a crop of rockweed in Nahant, Mass. (Photo by Daniel Hentz, [c] Woods Hole Oceanographic Institution) IN COLLABORATION WITH HIS [...]

Multi-year droughts are ever-present and transformational features of California’s Mediterranean climate and can fundamentally affect the water quality and the ecosystem responses of the San Francisco Estuary and the Sacramento–San Joaquin Delta. This study assessed data collected by long-term monitoring programs over the past 46 water years (1975–2021) to evaluate how water quality in the estuary changes during multi-year droughts. Data were aggregated by region (South-Central Delta, North Delta, confluence, Suisun Bay, and Suisun Marsh) and season, then differences between multi-year drought periods, multi-year wet periods, and neutral periods were compared using generalized linear models. We found that multi-year drought periods altered multiple physical and chemical parameters in the estuary, increasing water temperature, salinity, water clarity, and nutrient levels. This trend was consistent across regions and seasons, with few exceptions. Increases in these parameters during drought periods were likely caused by reduced Delta inflows that intensified in each successive dry year because of reduced precipitation and managed estuarine inflows and outflows. Drought periods did not substantially affect tidal velocities within the estuary, which remained mostly consistent across wet and drought periods. Trends in chlorophyll concentrations during drought periods were more nuanced with higher concentrations occurring in the South-Central Delta region and during the winter and spring. Together, these results characterized drought in the estuary as warm, clear, high in nutrients, with patchy phytoplankton blooms (as indexed by chlorophyll), all of which have implications for higher trophic levels. Considering that droughts are expected to increase in frequency and intensity in California with climate change, understanding the effects of multi-year droughts on the water quality conditions of the estuary can help inform water management decisions.

Droughts have major effects on estuaries because freshwater entry is one of the defining features of an estuary, and freshwater flow is an important variable that determines the interannual change in the environment. In the upper San Francisco Estuary (the Sacramento–San Joaquin Delta, Suisun Bay, and Suisun Marsh), the Mediterranean climate includes frequent multi-year droughts. To assess ecosystem responses to droughts in the upper estuary, the Interagency Ecological Program Drought Synthesis Team assembled a set of flow, water quality, chlorophyll, zooplankton, and fish data from 1975 to 2021 to test for differences between multi-year droughts and multi-year wet periods and tested for linear relationships between each variable and the Sacramento Valley Hydrologic Index (see definitions and relationships as outlined in Appendix A). Our models showed droughts decreased Delta outflow, project exports, zooplankton in Suisun Bay, and some fish species. We also found that droughts increased water clarity, salinity, nutrients, chlorophyll in the South Delta, zooplankton in the South Delta, and water residence time. Although our analyses only tested correlations, we hypothesized that most of the food-web responses could be traced to increased residence time, decreased transport rates, or both. However, some responses may have been caused by secondary effects, including shifts in salinity gradients, regional changes in water quality, or differences in top-down effects of increased predation and grazing rates. With increased frequency of droughts in the future, this increasingly low-outflow, warming, clearing estuary—which is invaded by non-native species and has low pelagic fish production—is rapidly becoming the new “normal.”

ABSTRACT The distribution and growth rate of juveniles of two myctophid species (Myctophum asperum and Symbolophorus evermanni) were examined in relation to environmental factors, based on samples collected in the Kuroshio Current system during winter from 2020 to 2022. The growth rate of juveniles was compared among three oceanic regions: the inshore side of the Kuroshio axis, the Kuroshio axis, and the offshore side of the Kuroshio axis in relation to sea surface temperature (SST), sea surface salinity (SSS), chlorophyll‐a concentration (CHL), and biomass of zooplankton (ZPB). M. asperum juveniles were distributed mainly in the inshore region and the Kuroshio axis of higher CHL and ZPB, whereas S. evermanni juveniles were distributed mainly in the Kuroshio axis and in the offshore regions of higher SST and SSS. No significant difference in growth rate was found among the three regions for M. asperum juveniles, whereas the growth rate of S. evermanni juveniles in the Kuroshio axis was higher than in the offshore regions. No environmental factors were selected for growth rate of M. asperum in the GLMM, whereas SST was selected for S. evermanni. M. asperum juveniles can be considered to have a higher tolerance for variability in environmental factors, whereas water temperature could be the driver for the distribution and growth rate of S. evermanni. Lastly, we discuss possible interspecific interactions among noncommercial fish (myctophids) and commercial fish (Pacific saury Cololabis saira). [ABSTRACT FROM AUTHOR]

Green tomatoes contain significant levels of steroidal glycoalkoids (SGA) such as α-tomatine and green pigment chlorophyll. Tomatine is an admixture of two glycoalkoids; alpha tomatine and dehydrotomatine reported various health beneficial biological activities. Moreover, a hydrolyzed product of tomatine also contributes to age-related atrophy, and muscle weakness and helps the elderly recover from illness and injuries related to age. However, there is a lack of evidence regarding the absorption of tomatine in the human body concerning proposed biological activity, which should be an area of interest in the future. Once, the absorption study is established compounds concentrated in green tomatoes are potentially involved as protective compounds for several diseases and also used for functional food. To facilitate the use of green tomatoes in food processing, this comprehensive review provides data on the nutritional value of green tomatoes, with emphasis on the evolution of the physiological chemistry, analytical, medicinal, and pharmacological effects of the α-tomatine and chlorophyll in an experimental model. The broad aim of this review is to evaluate the health benefits of green tomatoes in addition to their nutritional value and to study the several features of the role of α-tomatine and chlorophyll in human health. [ABSTRACT FROM AUTHOR]

The distribution characteristics of size-fractionated Chlorophyll a (Chl-a) and the environmental factors were studied in the coastal area of the Leizhou Peninsula in January 2022. The result showed that Chl-a ranged from 0.39 to 4.78 mg/m³ (averaging 1.21 mg/m³) at the surface and 0.43 to 2.78 mg/m³ (averaging 1.04 mg/m³) at the bottom layer, respectively. The spatial distribution of Chl-a concentration was associated with salinity. High Chl-a concentration was observed in the eastern part of the Leizhou Peninsula characterized by lower salinity, and low Chl-a concentration in Qiongzhou Strait with higher salinity. Nanophytoplankton (2-20 µm) was the dominant contributor, accounting for 61.3% and 63.7% of the total Chl-a at the surface and bottom layer, respectively. Both microphytoplankton (>20 µm) and nanophytoplankton displayed increased Chl-a with the increase in total Chl-a. Salinity, nutrients and temperature appear to influence the phytoplankton size structure in the coastal area of the Leizhou Peninsula. Additionally, the regulation of nutrient varied among phytoplankton of different sizes. This study contributed to our understanding of coastal ecosystem processes and has potential implications for coastal management and monitoring efforts. [ABSTRACT FROM AUTHOR]

Today, producing fruit or vegetable cubes with high solubility and dispersibility can attract consumers' attention, diminish agricultural waste, and raise people's access to important nutritional sources. In recent years, it seems that cube‐making preserves the appearance and marketability of food. In this study, the physicochemical properties of foam‐mat‐dried spinach powders with thicknesses of 3 and 5 mm produced at 40°C, 50°C, 60°C, and 70°C were investigated. The resulting powder was used to produce spinach cubes. The physicochemical properties of the powders were evaluated. With an increase in foam thickness, the water activity, moisture content, dissolution time, particle size, density, and porosity increased, whereas the hygroscopicity and glass transition temperature decreased. The lowest chlorophyll content (0.166 mg/g spinach) was observed in samples dried at 70°C and 5 mm. The samples dried at 70°C and 3 mm had the highest L∗ and higher stability (lower moisture content and water activity and higher Tg). The Heckel equation showed that the highest k value was related to the spinach powder produced at 70°C and 5 mm. The cubes with the greatest heights, the highest chlorophyll content (0.245 mg/g spinach), and the lowest dissolution time were obtained from powders produced at 40°C and 3 mm. The cube of the powder produced at 70°C and 5 mm had the longest dissolution time. All cubes had a non‐Fickian release in both dissolution media. The product of this research is dried spinach powder and its cubes. This product provides easy access to the valuable nutritional compounds of spinach in all conditions. This product is used as an additive in soup. It can also be used with yogurt and smoothies. [ABSTRACT FROM AUTHOR]

Chlorophyll in phytoplankton absorbs solar radiation (SR) and affects the thermal structure and dynamics within upwelling regions. However, research on this process across global‐scale coastal upwelling systems is still lacking. Here, we use a coupled ocean‐biogeochemical model to investigate differing responses to chlorophyll‐induced solar absorption between Pacific and Atlantic coastal upwelling regions. Chlorophyll‐induced solar absorption leads to colder Pacific coastal upwelling but warmer Atlantic coastal upwelling. In the Pacific, the shading effect of the surface chlorophyll maximum leads to colder subsurface water, which is then upwelled, contributing to cooling. The more stratified upper ocean leads to shallower mixed layer depth, intensifying offshore transport and upwelling. In the Atlantic, the absorption of SR by the subsurface chlorophyll maximum causes warmer and weaker upwelling. The processes described, in turn, trigger positive feedback to ocean biogeochemistry and potentially interact with climate dynamics, underscoring the necessity to incorporate them into Earth system models. Plain Language Summary: Chlorophyll and related pigments in phytoplankton play a key role in absorbing solar radiation and regulating ocean temperatures. In some coastal upwelling regions along the eastern boundaries of oceans, where chlorophyll concentrations are high, studies have suggested that the solar heat absorbed by chlorophyll can influence the temperatures and strength of upwelling. However, there is no study focusing on this process across global coastal upwelling zones. Here, we use computer simulations of ocean and phytoplankton to explore the effects of chlorophyll‐induced solar absorption on upwelling temperatures and strength on a global scale. Our study suggests that this effect varies between Pacific and Atlantic coastal upwelling regions due to their different spatial distributions of chlorophyll: surface chlorophyll in the Pacific warms the water after it has risen to the surface and as it is flowing offshore, while subsurface chlorophyll in the Atlantic warms the water before it rises to the surface. As a result, chlorophyll‐induced solar absorption leads to colder and stronger coastal upwelling in Pacific but warmer and weaker upwelling in Atlantic. Given the limited consideration of this process in previous studies, we emphasize the importance of incorporating it, along with regional differences, into future simulations. Key Points: Chlorophyll‐induced solar absorption leads to colder Pacific coastal upwelling but warmer Atlantic coastal upwellingIn Pacific, chlorophyll‐induced temperature variations intensify ocean stratification and coastal upwelling, in contrast to AtlanticChlorophyll‐induced variations in ocean physics trigger positive feedback, enhancing chlorophyll distributions in coastal upwelling regions [ABSTRACT FROM AUTHOR]

AbstractWater deficit is the most common abiotic stress and at least 75% of corn fields in Iran are exposed to drought stress during different stages of growth. humic acid (HA) and nanosilver (NS) can help mitigate abiotic stresses in plants; especially drought stress. A field experiment was conducted to study the effect of humic acid and nanosilver on the physiological traits and yield of corn during two crop years. Experimental treatments were including deficit irrigation (100%, 80%, 60% of crop water requirement (CWR)) and nanosilver (0 (NS0), 60 (NS60), 80 (NS80) and 100 (NS100) microliters/liter/ha) and humic acid (control (HA0), 500 (HA500) and 1000 (HA1000) g/ha). The highest amount of chlorophyll a, b and total in 100% CWR+NS60+HA1000 was obtained. The highest amount of proline in 60% CWR + NS60 +HA1000 as well as treatment NS0 +HA1000 were observed. In all irrigation levels, the application of NS100 has reduced chlorophyll a and total. The yield components were affected by HA and nanosilver foliar spraying. The highest grain yield was observed in 100% CWR with the application of NS60 +HA500 at the rate of 10,582 kg/ha. In conditions of 100% CWR, nanosilver concentrations had a positive effect on plant growth and yield, and with increasing stress, high concentrations of nanosilver had a negative effect on growth and yield, but with the combined application of nanosilver and HA, the effect of drought stress decreased, which indicates the positive effect of HA in improving plant growth and yield. [ABSTRACT FROM AUTHOR]

Chlorosis dormancy resulting from nitrogen starvation and its resuscitation upon available nitrogen contributes greatly to the fitness of cyanobacterial population under nitrogen-fluctuating environments. The reinstallation of the photosynthetic machinery is a key process for resuscitation from a chlorotic dormant state; however, the underlying regulatory mechanism is still elusive. Here, we reported that red light is essential for re-greening chlorotic Synechocystis sp. PCC 6803 (a non-diazotrophic cyanobacterium) after nitrogen supplement under weak light conditions. The expression of dark-operative protochlorophyllide reductase (DPOR) governed by the transcriptional factor RpaB was strikingly induced by red light in chlorotic cells, and its deficient mutant lost the capability of resuscitation from a dormant state, indicating DPOR catalyzing chlorophyll synthesis is a key step in the photosynthetic recovery of dormant cyanobacteria. Although light-dependent protochlorophyllide reductase is widely considered as a master switch in photomorphogenesis, this study unravels the primitive DPOR as a spark to activate the photosynthetic recovery of chlorotic dormant cyanobacteria. These findings provide new insight into the biological significance of DPOR in cyanobacteria and even some plants thriving in extreme environments. [Display omitted] • Red light activates photosynthesis of dormant cyanobacteria in nitrogen chlorosis • DPOR is required for weak red-light-induced resuscitation of chlorotic cells • The transcription factor RpaB regulates photosynthetic recovery • RpaB induction of the DPOR subunit ChlL is required for recovery Xu et al. unravel the key role of red light and the dark-operative protochlorophyllide reductase (DPOR) in the re-greening of dormant cyanobacteria in nitrogen chlorosis. These findings provide new insight into the biological significance of DPOR in cyanobacteria and some plants thriving in extreme environments. [ABSTRACT FROM AUTHOR]

The goal of this work was to evaluate the chemical constitution and health-promoting potential of 12 varieties of Chaenomeles × superba, speciosa and japonica leaves. Carotenoids, chlorophylls, triterpenes, sugars, polyols and acids were analyzed quantitatively and qualitatively using high pressure liquid chromatography (LC) coupled with mass spectrometry (MS), while the mineral profile was determined using atomic absorption spectroscopy (AAS). Moreover, the in vitro anticholinergic potential (inhibition of acetyl-cholinesterase (AChE) and butyryl-cholinesterase (BuChE)) and antioxidant (ABTS, FRAP, ORAC) capacity were evaluated. For the first time in Chaenomeles genotypes 26 carotenoid derivatives and 22 chlorophyll derivatives were identified. Some varieties contained high amounts of carotenoids and chlorophylls (Ch. × superba 'Colour Trail', 'Nicoline', 'Pink Lady', 'Texas Scarlet'), and triterpenes (Ch. speciosa 'Simonii', 'Rubra', and Ch. × superba 'Colour Trail', 'Nicoline') and showed high ORAC antioxidant (Ch. × superba 'Pink Lady' and Ch. speciosa 'Simonii') and anticholinergic (Ch. speciosa species) activity. The studied leaves also contained sugars (3.1 to 16.5 mg/100 g), organic acids (3.9–8.1 g/100 g), and minerals (Ca, Cu, Fe, K, Mg, Mn, Na, and Zn). In conclusion, Chaenomeles leaves show potential as a new source for the production of nutraceuticals, as well as for medical and/or cosmetic purposes. [ABSTRACT FROM AUTHOR]

In this study, we aimed to examine the growth, physiological and biochemical status, and responses to salinity stress of bok choy (Brassica rapa subsp. chinensis) cultivated in a hydroponic system with a plasma-treated solution. Plasma gas generated using a cylindrical dielectric barrier discharge or air (control) was injected into Hoagland nutrient solution once a week for different durations (0, 5, and 10 min). After 4 weeks, the length of the shoots and roots, number of leaves, and dry weight of bok choy plants significantly increased in individuals grown with Hoagland solution treated with plasma gas for 10 min. An increase in dry weight of individual plants of approximately 80.5% was observed in plants in the plasma-treated group compared to those in a control group. The levels of chlorophyll, total soluble proteins, and nitrogen uptake, and transcription of genes related to salinity stress tolerance--WRKY2, HHP3, and ABI1--were also significantly elevated in bok choy grown with plasma treated Hoagland solution. Moreover, when exposed to 20 mM NaCl, plant length and leaf number were significantly increased, in the group grown with Hoagland solution treated with plasma gas for 10 min. Level of H2O2 was significantly elevated in the treated nutrient solutions. In plants grown with the treated nutrient solution, intracellular NO was highly detected in the cell division and elongation zone of roots. Our findings suggest that plasma treatment of nutrient solutions in hydroponic culture systems may improve the growth, physiological and biochemical status, and tolerance to salinity stress in plants, and a crucial role of H2O2 generated in the treated nutrient solutions may play in this improvement. [ABSTRACT FROM AUTHOR]

Problem: Preterm birth (PTB) is a significant cause of maternal and neonatal morbidity and mortality worldwide. However, the effectiveness of progesterone (P4) which is clinically used for PTB management remains controversial and necessitates research into new therapeutic options Method of Study: In the current study, we investigated the effectiveness of two chlorophyll derivatives, pheophorbide a (PBa) and pheophytin a (PTa), in counteracting PTB. Timed‐pregnant mice (gestation day 17 ± 0.5) received lipopolysaccharide (LPS) (25 µg/mouse) or phosphate‐buffered saline (PBS) intraperitoneally, with PBa, PTa, progesterone (P4), and co‐administration of P4 and ibuprofen (IBP), administered orally 2 h prior. Results: The LPS group experienced PTB and 100% fetal mortality, whereas the PBa and PTa groups showed a delayed onset of LPS‐induced PTB, with significantly decreased PTB rate and fetal mortality. In addition, PBa and PTa suppressed LPS‐induced pro‐inflammatory cytokines and NF‐κB transcription factor while increasing anti‐inflammatory cytokines in the placenta and uterus. Conclusions: Our findings indicate that the chlorophyll derivatives, PBa and PTa increase fetal survival in infection‐induced PTB and demonstrate greater efficacy than P4 in preventing PTB. [ABSTRACT FROM AUTHOR]

Photosynthetic control (PCON) is a protective mechanism that prevents light-induced damage to PSI by ensuring the rate of NADPH and ATP production via linear electron transfer (LET) is balanced by their consumption in the CO2 fixation reactions. Protection of PSI is a priority for plants since they lack a dedicated rapid-repair cycle for this complex, meaning that any damage leads to prolonged photoinhibition and decreased growth. The imbalance between LET and the CO2 fixation reactions is sensed at the level of the transthylakoid ΔpH, which increases when light is in excess. The canonical mechanism of PCON involves feedback control by ΔpH on the plastoquinol oxidation step of LET at cytochrome b6f. PCON thereby maintains the PSI special pair chlorophylls (P700) in an oxidized state, which allows excess electrons unused in the CO2 fixation reactions to be safely quenched via charge recombination. In this review we focus on angiosperms, consider how photo-oxidative damage to PSI comes about, explore the consequences of PSI photoinhibition on photosynthesis and growth, discuss recent progress in understanding PCON regulation, and finally consider the prospects for its future manipulation in crop plants to improve photosynthetic efficiency. [ABSTRACT FROM AUTHOR]

In potato breeding, maturity class (MC) is a crucial selection criterion because this is a critical aspect of commercial potato production. Currently, the classification of potato genotypes into MCs is done visually, which is time- and labor-consuming. The objective of this research was to use vegetation indices (VIs) derived from unmanned aerial vehicle (UAV) imagery to remotely assign MCs to potato plants grown in trials, representing three different early stages within a multi-year breeding program. The relationships between VIs (GOSAVI – Green Optimized Soil Adjusted Vegetation Index, MCARI2 – Modified Chlorophyll Absorption Index-Improved, NDRE – Normalized Difference Red Edge, NDVI – Normalized Difference Vegetation Index, and OSAVI – Optimized Soil Adjusted Vegetation Index and WDVI – Weighted Difference Vegetation Index) and visual potato canopy status were determined. Further, this study aimed to identify factors that could improve the accuracy (decrease Mean Absolute Error – MAE) of potato MC estimation remotely. Results show that VIs derived from UAV imagery can be effectively used to remotely assign MCs to potato breeding lines, with higher accuracy for the potato B-clones (20 plants per plot) than the A-clones (6 plants per plot). Among the tested VIs, the NDRE allowed for potato MC evaluation with the lowest MAE. Applying NDRE for remote MC estimation using a validation dataset of potato B-clones (100 plants per plot), resulted in an MC estimate with a 0.81 MAE. However, the accuracy of potato MC estimation using UAV image-based methods should be improved by reducing the potato canopy's variability (increasing uniformity) within the plot. This could be achieved by minimizing 1) potato vines bending over the neighboring row, causing vine overlap between plots, and 2) plants damaged by tractor wheels during field operations. [ABSTRACT FROM AUTHOR]

The comparative efficacy of silicon (Si) and zinc (Zn) nanoparticles (NPs) in mitigating drought stress in fennel (Foeniculum vulgare) remains largely unexplored. This study evaluated the impact of Si NPs and Zn NPs on enhancing plant growth and physiological-biochemical attributes of fennel under varying irrigation regimes. The 2-year study was a split-pot design with irrigation at three irrigation levels (100, 75, and 50% field capacity, FC) and five treatments of foliar application of Si and Zn NPs (control, 1 mM Si NP, 2 mM Si NP, 1 mM Zn NP, 2 mM Zn NP). Results showed that drought stress reduced plant performance. Increases in superoxide dismutase (SOD, 131%) and catalase (CAT, 276%) were seen after a 50% FC drought without the use of Si and Zn NPs. Conversely, biological yield (34%), seed yield (44%), chlorophyll a + b (26%), relative water content (RWC, 21%), and essential oil (EO) yield (50%) were all reduced. However, application of Zn and Si, particularly 1 mM Si and 2 mM Zn, greatly mitigated drought stress via lowering CAT and SOD activity and enhancing plant yield, chlorophyll content, RWC, and EO. The composition of the EO consisted primarily of anethole, followed by limonene, fenchone, and estragole. During drought conditions, monoterpene hydrocarbons increased while oxygenated monoterpenes decreased. The opposite trend was observed for Si and Zn NPs. Our results suggest that applying Zn NPs at 2 mM followed by Si NPs at 1 mM improved plant resilience and EO yield in fennel plants under water stress. This study investigated the physiological and biochemical effects of foliar application of Si and Zn nanoparticles (NPs) on fennel (Foeniculum vulgare) plants under different irrigation levels. Si NPs and Zn NPs improved chlorophyll and water content of plants, and superoxide dismutase activity under drought stress, but essential oil content generally decreased by severe drought (50% field capacity). Superoxide dismutase and catalase activities were sensitive to drought, making them potential markers for monitoring fennel under drought stress. [ABSTRACT FROM AUTHOR]

To understand the effects and related potential mechanism of H2O2 on pigment metabolism in postharvest broccoli, an integrated analysis of transcriptome and metabolome was performed. Results suggested that 65 differentially expressed genes and 26 differentially accumulated metabolites involved in chlorophyll, carotenoid, and flavonoid metabolism were identified. H2O2 treatment delayed the decrease of chlorophyll content by upregulating the expressions of chlorophyll synthetic genes, thylakoid synthetic genes, and 15 light‐harvesting complex genes compared with the control and diphenylene iodonium treatments. H2O2 treatment decreased the accumulation of 11 flavonoids and 5 flavonols by downregulating the flavonoid synthetic genes. In addition, H2O2 treatment promoted carotenoid biosynthesis to eliminate reactive oxygen species in thylakoids, thereby protecting chlorophyll molecules from degradation. The inhibition of flavonoids and flavonols accumulation and chlorophyll decrease was the crucial reason for the delayed yellowing in H2O2 treatment. This study provides a new method and theoretical support for delaying the yellowing process in postharvest broccoli. [ABSTRACT FROM AUTHOR]

A selective and efficient olefin epoxidation has been developed by Fe3O4@SiO2/(TEMPO)-copolymer-(Chlorophyll b)-Co(III) NPs as a heterogeneous magnetically recyclable nanocatalyst. The nanocatalyst was synthesized through several steps including chlorophyll b de-metallation, imine functionalization with ally amine, co-polymerization with acrylated TEMPO, re-metalation with cobalt, and immobilization on magnetite NPs. Selective catalytic epoxidation of olefins was accomplished under mild conditions and in an O2 atmosphere. High selectivity and conversion were achieved for a variety of substrates. The results indicated a synergistic effect between TEMPO moieties and the coordinated Co(III) centers as two active sites. The epoxide products could be separated by the heterogeneous poly(benzoic acid) with the highest possible isolated yields. Also, the heterogeneous nanocatalyst could be recycled for at least 7 consecutive cycles with a negligible reactivity loss. A selective and efficient olefin epoxidation with smart isolation has been developed by Fe3O4@SiO2/(TEMPO)-copolymer-(Chlorophyll b)-Co(III) NPs under mild conditions. [ABSTRACT FROM AUTHOR]

Apart from their functions in the nervous system of animals, neurotransmitters operate as regulatory agents and signals in diverse kingdoms of life. Some neurotransmitters have recently been revealed to exert specific effects on microalgae, predominantly functioning as algal growth stimulators. This article presents new data on the effects of such neurotransmitters as serotonin, norepinephrine, dopamine, histamine, and acetylcholine on the fatty acid and pigment composition of the green microalga Scenedesmus quadricauda (Turp.) Breb. K-1149. It was established that acetylcholine and, to a lesser extent, histamine increased the total fatty acid content of S. quadricauda cells, whereas serotonin and dopamine decreased the fatty acid content. Acetylcholine, histamine, and norepinephrine elevated the percentage of polyunsaturated fatty acids; in contrast, serotonin and dopamine increased the share of saturated fatty acids. Acetylcholine and, to a lesser extent, norepinephrine increased the total chlorophyll content per gram of dry weight in S. quadricauda, while histamine decreased the chlorophyll content. Histamine also increased the chlorophyll a/chlorophyll b and carotenoid/chlorophyll ratios, which were decreased by dopamine. The data obtained are of biotechnological and ecological interest. The stimulation of fatty acid accumulation and the increase in the percentage of polyunsaturated species was caused by the neurotransmitters acetylcholine and histamine at low (1–10 μM) concentrations, which potentially enables facilitating the biotechnological production of health-promoting preparations for therapeutic and cosmetic purposes. However, other neurotransmitters (dopamine and serotonin) tested increased the relative content of saturated fatty acids; therefore, they apparently can be used to stimulate biofuel production, since saturated fatty acid-rich lipids are advantageous raw materials for biodiesel production. The impact of neurotransmitters on microalgal fatty acid composition and photosystem components may be considered in terms of ongoing chemical interaction between microalgae and other aquatic ecosystem components that are known to produce neurotransmitters. [ABSTRACT FROM AUTHOR]

Aquatic bryophytes are frequently used as bioindicators of water quality in rivers. Poor water quality increases physiological stress in moss, and stress levels can be estimated by measuring the concentrations of photosynthetic pigments and by calculating pigmentary indices. However, studies collecting many samples in a short time may need to store them until analysis. In the meantime, the pigments may suffer some degradation. Given the lack of studies on this problem for aquatic bryophytes, this one investigates the effect of three storage methods (refrigerated at 6 °C, frozen at − 20 °C and dried at room temperature) on the concentrations of chlorophyll a, chlorophyll b, pheophytin a and the following ratios: chlorophyll a/chlorophyll b, D430/D410, D665/D665a, D430/D665 and D480/D665 (where Dx is the absorbance at x nm) in the aquatic moss Fontinalis antipyretica. The results showed that refrigeration was the most suitable method, freezing might be suitable for some parameters, and drying was inadequate for this purpose. We recommend that all studies on photosynthetic pigments detail the time elapsed from collection to sample analysis, as well as the storage method used. [ABSTRACT FROM AUTHOR]

Spirulina (Arthospira platensis) is known for its rich content of natural compounds like phycocyanin, chlorophylls, carotenoids, and high protein levels, making it a nutrient-dense food. Over the past decade, research has aimed to optimize the extraction, separation, and purification of these valuable metabolites, focusing on technologies such as high-pressure processing, ultrasound-assisted extraction, and microwave-assisted extraction as well as enzymatic treatments, chromatographic precipitation, and membrane separation. In this study, various extraction methods (conventional vs. ultrasound-assisted), solvents (water vs. phosphate buffer), solvent-to-biomass ratios (1:5 vs. 1:10), and ultrafiltration (PES membrane of MWCO 3 kDa, 2 bar) were evaluated. The quantities of total protein, phycocyanin (PC), chlorophyll a (Cla), and total carotenoids (TCC) were measured. The results showed that ultrasound-assisted extraction (UAE) with phosphate buffer at a 1:10 ratio yielded a metabolite-rich retentate (MRR) with 37.0 ± 1.9 mg/g of PC, 617 ± 15 mg/g of protein, 0.4 ± 0.2 mg/g of Cla, and 0.15 ± 0.14 mg/g of TCC. Water extraction in the concentration process achieved the highest concentrations in MRR, with approximately 76% PC, 92% total protein, 62% Cla, and 41% TCC. These findings highlight the effective extraction and concentration processes to obtain a metabolite-rich retentate from Spirulina biomass, reducing the volume tenfold and showing potential as a functional ingredient for the food, cosmetic, and pharmaceutical industries. [ABSTRACT FROM AUTHOR]

(1) Background: Cultivating microgreens is emerging as an excellent market opportunity. Their easy, short, and sustainable production methods are the main reasons they are approved by growers. However, a feature that still prevents its further spread is the microbiological risk and their rapid senescence. The present study was conducted to evaluate the post-harvest storage and shelf life of arugula microgreens in different packaging through microbiological, physico-chemical, and sensory parameters; (2) Methods: Plants were stored at 5 °C in open air, vacuum sealed, and under modified atmosphere bags and tested at 0, 3, 5, 7, and 10 days; (3) Results: Microgreens stored in all packaging were safe for consumption within ten days. Regarding physical and chemical parameters, open packaging proved to be promising, with less weight loss and slower chlorophyll degradation. The sensory analysis demonstrated that the microgreens stored in the vacuum-sealed packaging showed a decrease in quality from the fifth day onwards for all attributes. However, the MAP presented good scores with a better visual quality, similar to the fresh microgreens. [ABSTRACT FROM AUTHOR]

Researchers and environmental managers need big datasets spanning long time periods to accurately assess current and historical water quality conditions in fresh and estuarine waters. Using remote sensing data, we can survey many water bodies simultaneously and evaluate water quality conditions with greater frequency. The combination of existing and historical water quality data with remote sensing imagery into a unified database allows researchers to improve remote sensing algorithms and improves understanding of mechanisms causing blooms. We report on the development of a water quality database "EstuarySAT" which combines data from the Sentinel-2 multi-spectral instrument (MSI) remote sensing platform and water quality data throughout the coastal USA. EstuarySAT builds upon an existing database and set of methods developed by the creators of AquaSat, whose region of interest is primarily larger freshwater lakes in the USA. Following the same basic methods, EstuarySAT utilizes open-source tools: R v. 3.24+ (statistical software), Python (dynamic programming environment), and Google Earth Engine (GEE) to develop a combined water quality data and remote sensing imagery database (EstuarySAT) for smaller coastal estuarine and freshwater tidal riverine systems. EstuarySAT fills a data gap that exists between freshwater and estuarine water bodies. We are able to evaluate smaller systems due to the higher spatial resolution of Sentinel-2 (10 m pixel image resolution) vs. the Landsat platform used by AquaSat (30 m pixel resolution). Sentinel-2 also has a more frequent revisit (overpass) schedule of every 5 to 10 days vs. Landsat 7 which is every 17 days. EstuarySAT incorporates publicly available water quality data from 23 individual water quality data sources spanning 1984–2021 and spatially matches them with Sentinel-2 imagery from 2015–2021. EstuarySAT currently contains 299,851 matched observations distributed across the coastal USA. EstuarySAT's primary focus is on collecting chlorophyll data; however, it also contains other ancillary water quality data, including temperature, salinity, pH, dissolved oxygen, dissolved organic carbon, and turbidity (where available). As compared to other ocean color databases used for developing predictive chlorophyll algorithms, this coastal database contains spectral profiles more typical of CDOM-dominated systems. This database can assist researchers and managers in evaluating algal bloom causes and predicting the occurrence of future blooms. [ABSTRACT FROM AUTHOR]

Singe‐turnover active chlorophyll a fluorometry (STAF) can be used to assess phytoplankton photosynthetic rates in terms of the photosystem II photochemical flux (JVPII, μmol e− m−3 s−1) instantaneously, autonomously, and at high resolution. While JVPII provides an upper limit to rates of phytoplankton primary productivity in units of carbon fixation, the conversion between these two rates is variable, limiting our ability to utilize high‐resolution JVPII data to monitor phytoplankton primary productivity. Simultaneous measurements of JVPII and 14C‐fixation help in understanding the factors controlling the variable ratio between the two rates. However, to date, methodological inconsistencies, including differences in incubation lengths and light quality, have greatly inhibited practical assessment of such electron to carbon ratios (Φe,C, mol e− mol C−1). We here present data from a range of dual‐incubation experiments in northeast Atlantic waters during which JVPII and 14C‐fixation were measured simultaneously on the same sample. Time‐course experiments show how Φe,C increases with incubation length, likely reflecting the transition from gross to net 14C‐fixation. Dual‐incubation experiments conducted under different light levels show a tendency for increased Φe,C under (super‐)saturating light. Finally, data from a diurnal experiment demonstrate how Φe,C increases over the course of a day, due to downregulation of 14C‐fixation. We provide a detailed description of our methodological approach, including a critical discussion of improvements to the calculation of JVPII implemented in the LabSTAF instrument used for active fluorescence measurements and the limitations of the well‐established 14C‐fixation approach. [ABSTRACT FROM AUTHOR]

Mesophotic coral ecosystems are characterised by the presence of photosynthetic scleractinian corals despite the decreasing amounts of light available with depth. To better understand physiological strategies across a broad depth gradient, we studied the biological trait responses of Pocillopora cf. verrucosa from 6 to 60 m depth and Pachyseris "speciosa" spp. from 20 to 90 m depth at four islands of French Polynesia. Specifically, we characterised associated Symbiodiniaceae communities, photophysiological traits (Symbiodiniaceae density and chlorophyll concentrations), micro-morphology and trophic plasticity (autotrophy vs heterotrophy inferred from stable isotopes). Our results showed that both taxa can live at mesophotic depths without significant genetic structuring in their generic Symbiodiniaceae communities, mainly composed of Cladocopium and Durusdinium. Yet, the prevalence of Symbiodiniaceae ITS2 profiles revealed location-based variations that sometimes interact with depth and highlight putative shallow- or depth-tolerant taxa. For both taxa, symbiont density and chlorophyll pigment concentrations increased with increasing depth. We also found a change in their skeletal micro-morphology with an increase in the inter-corallite distance for Pocillopora cf. verrucosa and a decrease in the height of septa for Pachyseris "speciosa" spp. with depth. Finally, we found no isotopic evidence of switching to a more heterotrophic diet as their primary energy source, although host–tissue δ13C ratios became more negative with depth in both corals. Overall, our findings show similarity (across the two species) and species-specific strategies (biological trait patterns with increasing depth) underlying the capacity of symbiotic scleractinian corals to live in low-light environments. [ABSTRACT FROM AUTHOR]

Parabens have been associated with health problems, and the inefficiency in conventional treatment systems to remove them has led to the search for alternative treatment methods, such as phytoextraction. Understanding the effect of parabens on the phytoextractor species is essential to develop an efficient alternative system. Thus, this study aims to evaluate the effect of Methylparaben and its chlorinated forms on the metabolism of Salvinia biloba and assess the possibility of its action as a phytoextractor. To do this, S. biloba was exposed to treatments with Methylparaben, Chloromethylparaben, and Dichloromethylparaben at concentrations of 100, 500, and 1000 µg/L. The phytoextract potential was assessed in the solutions after contact with the plants for phytotoxicity, genotoxicity and cytotoxicity tests with Allium cepa. The enzymatic anti-stress defense system, lipid peroxidation, and chlorophyll a and b concentrations were evaluated. The activity of the CAT and APX occurred in the chlorinated treatments. GOPX and SOD were significantly activated in response to lipid peroxidation. Chlorophyll a increased at 500 and 1,000 µg/L MPB, and chlorophyll b disappeared after 96 h in ClMPB and DiClMPB. The IM showed that MPB at the three concentrations caused reduction in the cell growth of A. cepa roots at all times of exposure. In treatments ClMPB and DiClMPB, after 72 h of treatment, root elongation was like that of the control. Thus, it is possible to affirm that S. biloba cannot absorb and transport methylparaben through its tissues but has phytoextractor potential for Chloromethylparaben and Dichloromethylparaben. [ABSTRACT FROM AUTHOR]

Understanding the stability of photosynthetic pigments is crucial for developing crop cultivars with high productivity and resilience to the environmental stresses. This study leveraged GGE biplot, WAASB, and MTSI indices to assess the stability of content and composition of photosynthetic pigments in leaves and siliques of 286 Brassica juncea (L.) Czern. genotypes across three environments. The GGE biplot analysis identified NRCQR-9901 as the best genotype in terms of chlorophyll 'a' under conditions of high irradiance and long days (E1). For chlorophyll 'b' and total chlorophyll, NC-533728 performed the best. AJ-2 and NPJ-208 had the maximum total carotenoids levels in leaves. RLC-2 was characterized by maximum values for chlorophyll a, chlorophyll b, and total chlorophyll in the siliques. The low irradiance, short days, and moderate to high temperatures (E2) seemed perfect for the synthesis of photosynthetic pigments. NPJ-182 shows the maximum concentrations of chlorophyll 'a', total chlorophyll, and total carotenoids in leaves. Conversely, IC-597869, RE-389, and IC-597894 exhibited the highest concentrations of chlorophyll 'b' under an environment characterized by low light intensity, shorter daylights, and low temperatures (E3) during flowering and siliqua formation stages. The combined analysis found NPJ-182, NC-533728, CN-105233, RLC-2, CN-101846, JA-96, PBR-357, JM-3, and DTM-34 as top performers with high stability. Comparative transcriptome analysis with two stable and high-performing genotypes (PBR-357 and DTM-34) and two average performers revealed upregulation of critical photosynthesis-related genes (ELIP1, CAB3.1, ELIP1.5, and LHCB5) in top performers. This study identified promising trait donors for use in breeding programs aimed at improving the mustard crop's photosynthetic efficiency, productivity, and stability. [ABSTRACT FROM AUTHOR]

Boron deficiency is a prevalent challenge for plant nutrition supply in many alkaline/calcareous soils. The current research aimed to examine the effects of boron supply to bell pepper plants through fertigation and foliar application. The experiment had seven treatments, comprising a control group, boric acid as fertigation (0.5, 1, and 2 g L-1), and foliar application (0.5, 1, and 2 g L-1) with three replications in controlled greenhouse conditions. The treatments were applied on Lorca bell peppers in a completely randomized design. The results showed that fertigation and foliar application increased all measured characteristics compared to the control group. Increasing the boric acid concentration in foliar application caused a decrease in fruit count per plant, fruit fresh weight, fruit yield per plant, and fruit width. Both fertigation and foliar boric acid applications at a low level (0.5 g L-1) and as separate treatments caused the highest fruit weight, length, width, and fruit count per plant. Higher boric acid concentrations increased chlorophyll a, b, total chlorophyll, leaf carotenoid content, soluble sugars, total soluble solids, titratable acidity, total phenols, and fruit ascorbic acid content. The highest chlorophyll a, b, total chlorophyll, leaf carotenoid content, and fruit ascorbic acid were observed in response to the high concentration of boric acid foliar application (2 g L-1). Overall, the boron supplement as a foliar application (0.5 to 1 g L-1) or fertigation (0.5 to 1 g L-1) improved quantitative and qualitative performance in bell peppers. [ABSTRACT FROM AUTHOR]

Plant growth in hydroponic systems is affected by the nutrient solution concentration. The present study evaluated the effects of nitrogen (N) and potassium (K) on the concentration of some nutrients, chemical fruit qualities, and yield in tomatoes (Solanum lycopersicum, cv. Hirad). The experiment was arranged as a completely randomized design with four treatments (T1: N160 + K350 ppm at the vegetative stage and N130 + K250 ppm at the reproductive stage, T2: N170 + K360 ppm at the vegetative stage and N140 + K260 ppm at the reproductive stage, T3: N180 + K370 ppm at the vegetative stage and N150 + K270 ppm at the reproductive stage and T4: N190 + K380 ppm at the vegetative stage and N160 + K280 ppm at the reproductive stage). Results indicated that higher N and K supplies in the nutrient solution decreased Ca, Na, Mn, and Zn concentrations in leaf samples. In contrast, the concentration of various elements in fruits was unaffected by the increase in N and K (except for Cu). The second treatment (T2) had the most beneficial effect on the Cu concentration in tomato leaves and fruits. The increase in total soluble solids, chlorophyll, lycopene, and total acids could improve fruit quality in tomato fruits. The best treatment in the present study was N170 + K360 ppm at the vegetative stage and N140 + K260 ppm at the reproductive stage. [ABSTRACT FROM AUTHOR]

Dust deposition can supply nutrients to the upper ocean, and subsequently affect primary production and biodiversity in planktonic ecosystem, but the differential response among taxa and their interactions are not fully understood. Here, we performed 7-day onboard incubation experiment amended with different dust loadings (0, 0.2 and 2 mg L-1) in the Kuroshio-Oyashio transition region of the Northwest Pacific Ocean and characterized the community structure and microbial network of a planktonic microbiome in response to dust addition. Chlorophyll a and nutrient analysis indicated that dust-derived nitrogen promoted the growth of phytoplankton (165.8-293.6%) and phytoplankton size structure shifted towards larger cells (>3 µm).Metabarcoding sequencing, targeting prokaryotic and eukaryotic microbes, revealed the changes in community structure and co-occurrence network in response to dust addition. Dust induced a shift from dinoflagellate dominance toward diatom dominance in phytoplankton, and favored members of Cercozoa, Labyrinthulomycetes and Saprospirae, which showed positive correlation with diatom. Temporal response patterns among taxa were categorized into five clusters, and collectively pointed to a more sensitive microeukaryotic community than prokaryotic one in response to dust. The community turnover during the incubation was dominated by moderate taxa with 55.71-62.26% moderate OTUs transitioning to abundant or rare taxa, and dust addition stimulated the transitions of rare taxa. Moreover, biotic factors shaped planktonic microbiome more than abiotic factors, particularly the cross-domain interaction significantly affected microeukaryotic community. Notably, dust addition enhanced the co-occurrence network complexity, with the number of keystone taxa increased, suggesting more interspecies interactions were induced by dust. With integrated analysis, our findings highlight the differential sensitivity of planktonic microbiome to dust deposition and the effects could pass on other organisms through interspecies interaction. [ABSTRACT FROM AUTHOR]

To investigate the response of blueberry photosynthetic physiology to different light intensities during different stages of fruit development. In this study, four light intensity treatments (25%, 50%, 75% and 100% of full light) were set up to study the change rule of photosynthetic pigment content and photosynthetic characteristics of 'O'Neal' southern highbush blueberry leaves during the white fruiting stage (S1), purple fruiting stage (S2) and blue fruiting stage (S3) under different light intensity environments, and to explore the light demand and light adaptability of blueberry during different developmental stages of the fruit. The results showed that the chlorophyll and carotenoid contents of blueberry leaves showed an increasing trend with decreasing light intensity at all three stages of fruit development. The total chlorophyll content of blueberry leaves at 25% light intensity increased by 76.4% compared with CK during the blue fruiting stage; the maximum net photosynthetic rate (Pmax), light compensation point (LCP), light saturation point (LSP), rate of dark respirations (Rd), inter-cellular CO2 concentration (Ci), stomatal conductance (Gs), transpiration rate (Tr), net photosynthesis rate (Pn), and chlorophyll a/b showed a decreasing trend with decreasing light intensity. The Pn of blueberry leaves was highest under full light conditions at all three stages, and the Pn at 25% light intensity decreased by 68.5% compared with CK during the white fruiting stage Reflecting the fact that blueberries can adapt to low-light environments through increases in chlorophyll and carotenoids, but reduced light intensity significantly inhibited their photosynthesis. The photosynthetic physiology of blueberry showed a consistent pattern at all three stages, but there were some differences in the changes of photosynthetic parameters at different stages. The results of the study can provide theoretical references for the selection of sites and density regulation in blueberry production. [ABSTRACT FROM AUTHOR]

Diatoms (> 2 mm) have traditionally been identified as the primary biological agents linking the carbon (C) and silicon (Si) cycles. However, recent research has shown that picophytoplankton species (< 2 mm) also play a crucial role in the intertwined Si-C biogeochemical cycling in marine ecosystems. In this study, we examined the spatial distribution and vertical variation of micro/nano-diatoms and picophytoplankton in the eastern Indian Ocean (EIO), aimed to differentiate the contributions of living carbon and biogenic silica (bSi) stocks between diatoms and picophytoplankton. The study revealed that the abundance of picophytoplankton surpasses that of diatoms by four to seven orders of magnitude. Synechococcus was predominantly presented in the upper layer, while Prochlorococcus, picoeukaryotes, and diatoms were primarily located in the middle layer. Aggregation Boosted Tree (ABT) and Generalized Additive Models (GAM) analyses revealed that temperature and silicate (DSi) levels strongly influenced the diatom and picophytoplankton communities in the EIO. The fractions smaller than 2 mm made substantial contributions of 86.20%, 55.69%, and 96.86% to chlorophyll a (Chl-a), particulate organic carbon (POC), and living carbon biomass, respectively, underscoring the ecological significance of picophytoplankton in the carbon cycle of oligotrophic regions. Picophytoplankton represented a 33.06% of bSi stocks in the area, comparable to the contribution of diatoms (> 20 mm). Moreover, estimated contributions of diatom living carbon and silicon quota averaged 0.47% and 0.66%, respectively, while that of Synechococcus stood at 2.58% and 1.77%, indicating the predominance of Synechococcus as a weakly siliceous organism with high cell abundance in oligotrophic seas. Overall, this study draws on data from diatom and picophytoplankton biomass in the EIO to offer insights into the disproportionate carbon and silicon budgets in oligotrophic oceans from a biological perspective. [ABSTRACT FROM AUTHOR]

The second near‐infrared window (NIR‐II, 1000–1700 nm) fluorescence imaging has attracted significant attention in research fields because of its unique advantages compared with conventional optical windows (400–900 nm). A variety of NIR‐II fluorophores have been actively studied because they serve as a key component of fluorescence imaging. Among them, organic small molecule NIR‐II fluorophores display outstanding imaging performance and many advantages, but types of small molecule NIR‐II fluorophores with high biocompatibility are still quite limited. Novel molecular scaffolds based NIR‐II dyes are highly desired. Herein, we hypothesized that chlorophyll is a new promising molecular platform for discovery NIR‐II fluorophores. Thus, seven derivatives of derivatives were selected to characterize their optical properties. Interestingly, six chlorophyll derivatives displayed NIR‐II fluorescence imaging capability. This characteristic allowed the successful NIR‐II imaging of green leaves of various plants. Furthermore, most of these fluorophores showed capacity to monitor viscosity change because of their sensitive for viscosity. For demonstration of its biomedical applications, these probes were successfully used for NIR‐II fluorescence‐guided surgical resection of lymph nodes. In summary, chlorophylls are novel valuable tool molecules for NIR‐II fluorescence imaging and have potential to expand their applications in biomedical field and plant science. [ABSTRACT FROM AUTHOR]

As a master regulator of seed development, Leafy Cotyledon 1 (LEC1) promotes chlorophyll (Chl) biosynthesis in Arabidopsis, but the mechanism underlying this remains poorly understood. Here, we found that loss of function of OsNF-YB7, a LEC1 homolog of rice, leads to chlorophyllous embryo, indicating that OsNF-YB7 plays an opposite role in Chl biosynthesis in rice compared with that in Arabidopsis. OsNF-YB7 regulates the expression of a group of genes responsible for Chl biosynthesis and photosynthesis by directly binding to their promoters. In addition, OsNF-YB7 interacts with Golden 2-Like 1 (OsGLK1) to inhibit the transactivation activity of OsGLK1, a key regulator of Chl biosynthesis. Moreover, OsNF-YB7 can directly repress OsGLK1 expression by recognizing its promoter in vivo, indicating the involvement of OsNF-YB7 in multiple regulatory layers of Chl biosynthesis in rice embryo. We propose that OsNF-YB7 functions as a transcriptional repressor to regulate Chl biosynthesis in rice embryo. [ABSTRACT FROM AUTHOR]

Amphibian larvae can affect the structure and functioning of freshwater ecosystems, but their effects have been little explored although amphibian biodiversity is rapidly declining. Given that larvae of different amphibian species belong to different trophic levels, their effects on freshwater communities and processes can be expected to differ, with herbivores likely having direct effects on algae and predators having indirect effects through trophic cascades. We explored this question through a mesocosm experiment conducted in montane ponds, using an anuran and a urodele species affected by emergent diseases. We used different scenarios of reduction and loss of one or both species, and compared them to a control scenario representing a typical amphibian community in the study area composed of four species, with total larval density held constant. Loss of the anuran resulted in lower chlorophyll concentration and algal density, likely due to replacement by more efficient grazers. Loss of the urodele produced similar trends but weaker, possibly due to an increase of invertebrate grazing activity in the absence of this predator. Our study shows how the loss of amphibian species can alter the structure of montane ponds, but also how the mechanisms involved and the intensity of effects differ for different species. [ABSTRACT FROM AUTHOR]

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AbstractThis study investigated the effects of various fertilizers on the leaf chlorophyll content of the Simpatico (FAO300) silage corn variety under field conditions. Different application combinations were tested, including treatments with and without foliar fertilizers. The foliar fertilizers used were seaweed (SW), humic acid (HA), and vermicompost (VC), combined with granular fertilizers DAP, UREA, OMB, and OMT. Granular fertilizers were applied to the soil, while foliar fertilizers were applied at four different stages: the 4-6 leaf period, 11-13 leaf period, 14-16 leaf period, and at corn tassel. Chlorophyll content in plant leaves was measured using a SPAD-502 device during these periods. The highest SPAD chlorophyll ratios were recorded with OMB-OMT (42.583) and DAP-OMT (42.150) treatments, which did not include foliar fertilizers. Conversely, the lowest SPAD chlorophyll ratio, 28.983, was observed in the DAP-UREA treatment. Treatments with foliar fertilizers resulted in an increase in SPAD chlorophyll by 11.3% to 15.7%, with the greatest improvements observed with vermicompost and humic acid, compared to treatments without foliar fertilizers. Additionally, analysis of periodic effects showed that the highest SPAD chlorophyll ratios were found during the third and second measurement periods, while the lowest ratios were observed in the first measurement period. The use of organo-mineral fertilizers and foliar applications of vermicompost and humic acid were found to enhance the leaf chlorophyll content of corn. [ABSTRACT FROM AUTHOR]

AbstractWater deficit stress (WDS) is one of the most significant abiotic limiting factors in cultivated crops, including cotton (Gossypium barbadense L.). With global climate change and the destruction of ecological balance, the frequency and severity of drought events are increasing in many regions around the world. Therefore, the aim of the present work was to investigate the potential of using nano zinc particles (ZnO-NPs), plant growth-promoting rhizobacteria (Azospirillum sp.), and their combination to mitigate the negative impacts of WDS on cotton var. Giza 96. Extended irrigation intervals of 30 and 45 days led to considerable decreases in plant height, chlorophyll content, relative water content (RWC), yield, and cotton fiber quality compared to the optimal irrigation interval (every 15 days). When applied individually or in combination, ZnO-NPs and Azospirillum sp. can ameliorate the negative effects of WDS on cotton growth and productivity. Overall, the use of Azospirillum sp. and ZnO-NPs, either individually or in combination, has demonstrated their potential to enhance cotton growth and yield parameters (plant height, dry weight, leaf area, chlorophyll pigment, seed index, seed yield, and lint%) under prolonged irrigation intervals during 2021 and 2022 seasons. Antioxidant enzymes activity comprising catalase (CAT), peroxidase (POD), and polyphenol oxidase (PPO) and proline content were increased under drought stress. Cotton fiber quality parameters including length, strength, and micronaire were insignificantly affected under low irrigation rate. The combination of ZnO-NPs and Azospirillum sp. provided the most effective mitigation of WDS during both experimental seasons, outperforming the effects of individual applications. [ABSTRACT FROM AUTHOR]

Asymmetric warming refers to the difference between the increase in daytime maximum temperature and the increase in nighttime minimum temperature and has been documented in temperate regions. However, its impacts on seedling growth have been largely ignored. In this study, seedlings of a widely distributed tree species, Acer mono Maxim., were exposed to both symmetric warming (SW) and asymmetric warming scenarios (day warming [DW], night warming [NW] and diurnal asymmetric warming [DAW]). Compared to control, all warming scenarios were found to enhance belowground biomass. DW promoted the seedling growth, while NW reduced the stem biomass. DAW did not impact the total biomass relative to the control. Compared to SW, DAW advanced phenology, increased indole‐3‐acetic acid content and chlorophyll content, which enhanced total biomass and stored more NSC in the root. Future DAW would be not beneficial to the growth of A. mono seedlings by comparing with the control. This research encourages further exploration of tree growth experiments under asymmetric warming conditions, as most studies tend to underestimate the warming effects on plant growth by focusing on SW. Incorporating the responses of seedling physiology and growth to non‐uniform diurnal warming into earth system models is crucial for more accurately predicting carbon and energy balances in a warmer world. [ABSTRACT FROM AUTHOR]

Lithium (Li) exploitation promotes socioeconomic advances but may result in harmful environmental impacts. Thus, species selection for recovering environments degraded by Li mining is essential. We investigated the tolerance and early growth of four tree species to Li ore tailings (LOT), Enterolobium contortisiliquum and Handroanthus impetiginosus with wide geographic distribution and Hymenaea courbaril and H. stigonocarpa with restricted geographic distribution. The plants grew in LOT and soil for 255 days to evaluate photosynthesis, growth, and mineral nutrition. LOT negatively affected species growth, reducing the length of stems, roots, and biomass through structural and nutritional impoverishment. LOT favored the accumulation of Mg and decreased the absorption of K. The species presented a reduction in potential quantum efficiency and the chlorophyll index (b and total). E. contortisiliquum was the least tolerant species to LOT, and H. courbaril and H. stigonocarpa maintained their mass production in LOT, indicating greater tolerance to tailings. Furthermore, H. courbaril presented a translocation factor > 1 for Li and Mn, indicating the potential for phytoextraction of these metals. Our results offer first-time insights into the impacts of LOT on the early development of tree species with different geographic distribution ranges. This study may help in the tree species selection with a phytoremediation role, aiming at the recovery of areas affected by Li's mining activity. [ABSTRACT FROM AUTHOR]

Adaptation of reef-building corals to global warming depends upon standing heritable variation in tolerance traits upon which selection can act. Yet limited knowledge exists on heat-tolerance variation among conspecific individuals separated by metres to hundreds of kilometres. Here, we performed standardized acute heat-stress assays to quantify the thermal tolerance traits of 709 colonies of Acropora spathulata from 13 reefs spanning 1060 km (9.5° latitude) of the Great Barrier Reef. Thermal thresholds for photochemical efficiency and chlorophyll retention varied considerably among individual colonies both among reefs (approximately 6°C) and within reefs (approximately 3°C). Although tolerance rankings of colonies varied between traits, the most heat-tolerant corals (i.e. top 25% of each trait) were found at virtually all reefs, indicating widespread phenotypic variation. Reef-scale environmental predictors explained 12–62% of trait variation. Corals exposed to high thermal averages and recent thermal stress exhibited the greatest photochemical performance, probably reflecting local adaptation and stress pre-acclimatization, and the lowest chlorophyll retention suggesting stress pre-sensitization. Importantly, heat tolerance relative to local summer temperatures was the greatest on higher latitude reefs suggestive of higher adaptive potential. These results can be used to identify naturally tolerant coral populations and individuals for conservation and restoration applications. [ABSTRACT FROM AUTHOR]

Hyperspectral imaging technology can record the spatial and spectral information of the targets and significantly enhance the levels of military reconnaissance and target detection. It has scientific importance to mimic "homochromatic and homospectral" camouflage materials that have hyperspectral similarity with the green vegetation, one of the most common natural backgrounds. It is a big challenge to exquisitely simulate the spectral of green vegetation in visible and near‐infrared windows because of the slight differences between the artificial green dyes and vegetation, the instability of chlorophylls, and the easy loss of hydroxide bands due to the loss of water from the camouflage materials. Herein, a novel kind of biomimetic material of green vegetation was designed through the incorporation of chlorophylls into the crystal lattices of single‐crystalline anhydrous guanine microplates for the first time. The synthesized chlorophylls‐doped anhydrous guanine crystals exhibit high reflectance intensity and depolarization effect, thus can be applied as biomimetic camouflage materials that mimic green vegetation with high reflectivity and low polarization in the visible and near‐infrared regions. The factors influencing the formation of dye‐doped organic crystals under mild conditions were thoroughly investigated and the characterizations using electron microscopies and fluorescence confocal laser scanning microscopy clearly confirm the occlusion of chlorophylls into the crystal lattices of guanine crystals. The thermal stability experiments clearly indicate that the chlorophylls‐doped guanine crystals possess long‐term stability at high temperature. This study provides a new strategy for the synthesis of multifunctional materials comprised of organic crystals. [ABSTRACT FROM AUTHOR]