Chl Content Research Articles

Chlorophyll in water and bottom sediments as an indicator of the trophic state of Busse Lagoon (Sakhalin Island)

New associated data on the content of chlorophyll a and its derivatives in the water and bottom sediments of Busse Lagoon (Sakhalin Island) have been obtained. Chlorophyll a and chlorophyll degradation products (Chl a + Ph) in the water column is represented predominantly by the active form (61.4 ± 1.1%), in bottom sediments – by a product of its degradation (84.7 ± 2.5%). The connection between pigments in water and bottom sediments, as well as the abiotic conditions of primary production, has been revealed. For the first time, for a unique reservoir characterized by overgrowth of aquatic vegetation, silt accumulation and regular death of aquatic organisms, the similarity of the average annual sedimentation rate in the lagoon with the ratio of pelagic and benthic pigments was shown. The prevailing importance of the biotic factor in the formation of trophic conditions has been established. Based on the average content of Chl a + Ph in water (4.1 ± 0.8 mg/dm3) and in bottom sediments (13.5 ± 4.0 μg/g d.s.), Busse Lagoon is a mesotrophic reservoir. Trophic state of benthic in the period 2013–2021 is preserved, remaining oligotrophic in the shallow coastal zone and mesotrophic in the central part of the lagoon.

Phytoplankton Chlorophyll Trends in the Arctic at the Local, Regional, and Pan‐Arctic Scales (1998–2022)

AbstractWe analyzed the temporal trends (1998–2022) of surface phytoplankton Chlorophyll (Chl) concentration in the Arctic at the local, regional, and pan‐Arctic scales. We used four empirically derived Chl satellite ocean color products: two global merged products and two MODIS products, one calibrated to the Arctic. At the local level, between 10% and 40% of the area with valid pixels showed statistically significant Chl trends, with of those pixels showing increases, and the other third indicating a decrease. At the regional level, only the Barents and Chukchi Seas had consistent Chl increases across products. At the pan‐Arctic level, most products showed Chl increases in the months of July and September (0.3%–0.9% Chl ), even after removing the effect of new open water pixels. Overall, Chl is changing in the Arctic, although trends vary threefold depending on the product and spatial‐averaging assumptions used.

Structural and functional parameters of the Black Sea phytoplankton during the summer bloom of the coccolithophore Emiliania huxleyi

The aim of the study was to examine the main primary production indicators, describe the controlling factors and identify the conditions for the weak bloom of Emiliania huxleyi in the Crimea coast of the Black Sea during June – July 2022. The surface chlorophyll a (Chl a) varied between 0.3 to 1.5mgm-3 and primary production (PP) within 12–174mgC m-3 day-1. The integrated concentration of Chl a in the euphotic layer was 4–29mgm-2, and that of PP - 240–835mgC m-3 day-1. On average, 49% of Chl a was located bellow the photosynthetic zone. The relationship between integral PP and the total Chl a, nitrogen (nitrates and ammonium), phosphates and silicates in the euphotic layer, analyzed by a multiple regression, showed that 70% of the PP variability was accounted for by the first three variables. While the significance of total Chl a was the highest, followed by phosphates, nitrogen had a negligible effect and that of silicates was not detected. In the surface layer (0–1m), the total phytoplankton biomass was co-dominated by dinoflagellates, the large cell diatom Pseudosolenia calcar-avis and the coccolithophore E. huxleyi. A weak bloom of E. huxleyi (cell abundance 1.0–1.8·106 cells L-1) was detected at 11 out of the 23 sampling stations. The relatively large thickness of the upper mixed layer (about 10m on average) and phosphorus deficiency were the main factors limiting the bloom of this coccolithophore.

Physio-biochemical responses of three sunflower (Helianthus annuus L.) lines to phosphate solubilizing bacteria and phosphorous-enriched biochar in saline soils

The usage of microbes and biochar (BC) is fundamental in decreasing the impacts of salinity stress by promoting plant growth and development. The purpose of this study was to determine the impact of phosphate solubilizing bacteria (PSB) and phosphorous (P)-enriched BC on the plant growth and biochemical characteristics for three lines of sunflower (Helianthus annuus L.) in saline soils. The study was designed with salinity at 100 mM NaCl and PSB (Bacillus subtilis) with 109 CFU and BC at 1500 Kg ha-1 in the sunflower lines including RGK38 (salt-sensitive), BGK35 (salt-moderately sensitive), and BGK259 (salt-tolerant) based on completely randomized block design (CRBD) in five replicates. Salinity considerably reduced grain yield, thousand grain weight (TGW), oil content, oil yield, chlorophyll (Chl) content, relative water content (RWC), K, and P, while enhancing malondialdehyde (MDA), electrolyte leakage (EL), Na+, and Cl- in all lines of sunflower with high rate in RGK38. The use of integrated PSB and BC contributed to increases in plant yield. In RGK38 exposed to salinity, PSB+BC raised grain yield (16%), oil yield (27%), RWC (14%), Chl a+b (24%), K (22%), P (127%), but lowered MDA (26%), Na+ (36%), and Cl- (41%). Heat map analysis revealed that RGK38 stood out significantly from the other two sunflower lines with the maximum variability under the treatments. MDA showed the most variability among the lines as an indicator of identifying the susceptibility to salinity, PSB, and BC. This study has encouraging implications for agricultural operations in stress-affected areas by highlighting the potential of combining PSB and BC as environmentally acceptable and sustainable ways to increase plant resilience in salty soils.

Electrospinning of Poly-3-Hydroxybutyrate Fibers Loaded with Chlorophyll for Antibacterial Purposes.

This work is devoted to the creation of biocompatible fibrous materials with a high antimicrobial effect based on poly-3-hydroxybutyrate (PHB) and chlorophyll (Chl). The data obtained show the possibility of obtaining fibrous materials from PHB and Chl by electrospinning methods. The obtained electrospun matrices were investigated by the SEM, DSC and FTIR methods. Various key properties of the matrices were evaluated, including hydrophilicity and mechanical strength, as well as photodynamic and light-dependent antimicrobial effects against the conditionally pathogenic microorganism Staphylococcus aureus. The results demonstrate a significant improvement in electrospinning properties for a concentration of 0.5% Chl and a reduction in fiber formation defects, as well as an increase in the strength of nonwovens. It was found that the antimicrobial potential of Chl-PHB (with concentrations of Chl of 1.25 and 1.5%) is higher than that of Chl in free form. It was also determined that irradiation increases the inhibitory effect of Chl, both in free form and in the form of a complex with a polymer.

Quercetin promotes the recovery of iron chlorosis in strawberry plants

Iron (Fe) chlorosis is very common in plants cultivated in calcareous soils of the Mediterranean basin and is usually corrected by the application of Fe chelates to the soil, which can have a negative impact on the environment. The aim of this experiment was to assess the role of quercetin, a natural compound widely present in plants and known to bind Fe, in correcting Fe chlorosis when supplied in the Hoagland nutrient solution. In this context, strawberry plants were grown at different Fe concentrations, with 0 (Fe0), 1 (Fe1) and 5 (Fe5) μM of Fe in the nutrient solution, until the onset of clear Fe chlorosis symptoms. Subsequently, the recovery of Fe chlorosis was investigated through the addition of Fe and/or quercetin (Q) to nutrient solutions. Throughout the experiment, leaf chlorophyll (Chl) was estimated using the SPAD values. The root ferric chelate-reductase (FCR) activity was determined in the root apices, and the foliar Fe concentration was also quantified. At the end of the experiment, plants grown without Fe but supplemented with Fe1 plus quercetin [Fe0+(Fe1+Q)] recovered completely from Fe chlorosis and showed a Chl concentration (700–800 μmol m−2) in young leaves similar to that observed in control plants (Fe5). The remaining treatments exhibited lower Chl concentrations, with values ranging from 92.4 to 217.0 μmol of Chl per m2. FCR activity was approximately five-to six-fold higher in the Fe0+(Fe1+Q) treatment than in the Fe0 and Fe5 treatments. However, the plants that were consistently grown with Fe in the nutrient solution (Fe1 and Fe5) exhibited the highest Fe content in their leaves. The findings suggest that quercetin has the potential to function as an Fe complexing agent, thereby enhancing the recovery of strawberry plants with Fe deficiency.

Climate drivers of phytoplankton production along the Chilean coast

The west coast of South America is known for its high primary productivity. The level of phytoplankton can be measured through satellite images that detect chlorophyll (Chl), which is dependent on several oceanographic and meteorological parameters. Climate drivers such as El Niño Southern Oscillation (ENSO) and the Southeast Pacific Subtropical Anticyclone (SPSA) affect these parameters and, consequently, the phytoplankton. The objective of this study was to identify the impact of ENSO on SPSA, climate variables, and phytoplankton patterns. Composites were created using the years selected with either strongly positive or negative ENSO to understand their influence on different parameters. To create the Chl composite, it was necessary to extend it using Canonical Correlation Analysis (CCA) based on the sea surface temperature (SST) pattern. The study concludes that ENSO has a noticeable impact on Chl, mainly in the Southern Zone during the warm season. This is driven by the expansion of SPSA to the South, which increases the sea level pressure (SLP) in that region. However, predicting the Chl concentration has a high degree of uncertainty due to its complexity.

Activity of photosynthetic pigments and the antioxidant system in sunflower under drought stress

Background. The study is of particular importance in view of the increasing pace of global climate aridization. The article highlights the results of an experiment on the effect of drought on the physiological status of seedlings of cv. ‘Poseidon 625’ representing an important food crop – sunflower (Helianthus annuus L.). Materials and methods. The experiment included a group of control samples grown with sufficient moisture and four impact groups subjected to osmotic stress. The intensity of accumulation of lipid peroxidation products (LPP) was measured by the reaction of malondialdehyde (MDA) with thiobarbeturic acid; catalase activity was assessed by a photocolorimetric method based on the interaction between hydrogen peroxide and potassium iodide; the content of pigments (Chl a, Chl b, Сar) was calculated spectrophotometrically in acetone extract. Results. The degree of POL accumulation in the impact groups of the experiment was found to be many times higher than the values in the control samples, which was confirmed by a rapid increase in the MDA concentration in response to a growing water shortage. The accumulation of oxygen free radicals triggered the mechanisms of antioxidant protection of seedlings by synthesizing catalase, the concentration of which increased proportionally to the accumulation of POL. At the same time, the rapid accumulation of POL in the absence of irrigation and under osmotic stress of 3 and 5 atm led to a suppression of low-molecular-weight components of protection (carotenoids) and activation of their synthesis only when critical values of osmotic stress were reached. Conclusion. As a result of the experiment, catalase was identified as the main component of antioxidant protection in sunflower seedlings. Due to the activation of its synthesis, the concentrations of Chl a and Chl b decreased, attesting to the activation of the mechanisms protecting the photosynthetic activity in seedlings, and their antioxidant status.

Pollution resistance and removal efficiency of mesophytic plants of polluted water bodies

With the development of cities and economic growth, the eutrophication of urban park landscape water has become a hot topic in environmental governance and research at home and abroad. Using indoor water pollution simulation experiments, the decontamination and pollution resistance performance of six aquatic plants were studied. The research results found that all six aquatic plants can reduce the pH value of eutrophic water bodies. The pH of the Lythrum salicaria L. (Q) and Iris tectorum Maxim (Y) treatment systems was the lowest which are 7.34 and 7.48, respectively. They were significantly lower than the control group (CK). The content of nitrogen and phosphorus elements were reduced by six types of plants in the wastewater. After the completion of the experiment, the total nitrogen (TN) removal efficiency of Y was as high as 66.2%, and its content decreased from 9.49 to 3.21 mg/l. The removal rates of total phosphorus (TP) by six types of plants ranged from 59.1 to 81.3% and they were significantly higher than the CK. Among them, the removal rate of TP in wastewater by Y treatment exceeded 80%, which is superior to other plants and significantly different from CK. After the completion of the experiment, the content of chlorophyll a (chl a) in the water treated with Y was the lowest (6.6 mg/l). It was significantly lower than the other treatments (P<0.05). The contents of chl a in Y decreased by 37.1% compared to the initial level. Compared to CK, it is 54.1% lower and the content of chl a in CK showed an increasing trend with time delay. Overall analysis shows that the microsystems formed by the six plants all have a certain improvement effect on water quality, effectively inhibiting the proliferation of algae in eutrophic water bodies. Among them, planting iris has the best effect. Bangladesh J. Bot. 53(3): 757-763, 2024 (September) Special

Integrated transcriptomics, metabolomics and physiological analyses reveal differential response mechanisms of wheat to cadmium and/or salinity stress.

Many soils face dual challenges of cadmium (Cd) contamination and salinization. However, the response of crops, especially wheat, to combined Cd and salinity stress is not understood. Here, wheat was grown in a hydroponic model for 14 days under single and combined Cd and NaCl stresses. Growth parameters, tissue Cd2+ and Na+ contents, and leaf chlorophyll (Chl), O2•-, and MDA levels were determined. Comparative transcriptomic and metabolomic analyses of the leaves were performed. The results showed that combined stress had a greater inhibitory effect on Chl contents and generated more O2•- and MDA, resulting in more severe wheat growth retardation than those under Cd or NaCl stress. Stress-induced decrease in Chl levels may be attributed to the inhibition of Chl biosynthesis, activation of Chl degradation, or a decline in glutamate content. Cd addition weakened the promotional effect of NaCl on SOS1 gene expression, thereby increasing the Na+ content. Contrastingly, NaCl supplementation downregulated the Nramp and ZIP gene expressions related to Cd uptake and transport, thereby impeding Cd2+ accumulation. All stresses enhanced tryptophan content via promoting tryptophan biosynthesis. Meanwhile, Cd and NaCl stresses activated phenylpropanoid biosynthesis and purine metabolism, respectively, thereby increasing the levels of caffeic acid, fumaric acid, and uric acid. Activating the TCA cycle was important in the wheat's response to combined stress. Additionally, NaCl and combined stresses affected starch and sucrose metabolism, resulting in sucrose and trehalose accumulation. Our findings provide a comprehensive understanding of the response of wheat to the combined Cd and salinity stress.

Exhausted plant cell culture media as potential biostimulants to enhance plant growth and nitrogen use efficiency in tomatoes under optimal and reduced nitrogen supply

AbstractBackgroundInefficient nitrogen (N) use leads to economic losses and environmental harm. Improving N use efficiency (NUE) is crucial. The use of plant biostimulants (PBs), integrated with good agronomic practices, offers a sustainable solution.AimsThe study explores the potential use of exhausted cell culture media from plant cell cultures (Nicotiana sp. and Gardenia sp.) as PBs, assessing their role in enhancing plant physiological status and NUE. It also compares their effectiveness against commercial PBs.MethodsTwo experiments (Experiments 1 and 2) were conducted using cherry tomato plants. In the first one, the two media were applied at different concentrations as a foliar spray to define the optimal dose. This outcome was used to set up Experiment 2, in which both media were compared to commercial PBs under optimal and reduced N supply. Measurements included plant growth, chlorophyll (Chl) content, and NUE indices. Moreover, Experiment 2 examined gene expression related to N assimilation, transport, and response to oxidative stress.ResultsBoth experiments demonstrated a significant increase in leaf area (≈11%) and aboveground biomass (≈13%) using exhausted media. Furthermore, Experiment 2 demonstrated enhancements in Chl content (≈10%) and plant N accumulation (≈20%). These findings indicate that exhausted media has a comparable efficacy to commercial PBs.ConclusionsThe study underscores the practical viability of exhausted cell culture media as effective PBs for tomato growth in both N conditions. This approach aligns with sustainability objectives by repurposing by‐products to enhance plant resilience against abiotic stress and potentially improve the efficiency of N fertilizers.

Mapping of the Spatio-Spectral Dynamics of Mangrove Chlorophyll Concentrations via Sentinel-2 Satellite Imagery

Mangrove ecosystems play a critical role in maintaining coastal health; however, they are increasingly threatened by anthropogenic activities and climate change. Health assessment is essential for effective conservation efforts. However, traditional remote sensing techniques such as the normalised difference vegetation index (NDVI) may not fully capture the complex physiological processes influencing vegetation health. Therefore, this study investigated chlorophyll (Chl) dynamics in mangroves using remote sensing techniques, including the NDVI and a novel method, the normalised area over reflectance curve (NAOC), via Sentinel-2 satellite imagery during October 2023, and analysed spatial variations in Chl content (CC) via the Google Earth Engine API. NDVI and NAOC-Chl were weakly correlated (0.47), highlighting their complementary roles. The average NDVI and NOAC-Chl values for different species were analysed, and Rhizophora mucronata presented the highest value (NDVI: 0.86 ± 0.08, NOAC: 20.48 ± 4.49.

Sustainable regulation of calcium magnesium phosphate and rapeseed cake on soil-tea system in Mount Lushan, China.

Lushan Yunwu tea quality is limited by soil acidity and sterility. This article examined a 3-year localization experiment at 1100m altitude to demonstrate the sustainable management of conditioners, calcium magnesium phosphate (P), rapeseed cake (C), and combination application (P + C) by one-time application on the soil-tea system in Mount Lushan. The study found that conditioners (P, C, P + C) reduced soil acidification and maintained a pH of 4.75-5.34, ideal for tea tree development for 3years. Phosphorus activation coefficient (PAC), nitrogen activation coefficient (NAC), and organic matter (OM) content were significantly higher (P < 0.05) in the first year after conditioner treatment, with P + C being the best. After P + C, PAC, NAC, and OM rose by 31.25%, 47.70%, and 10.06gkg-1 compared to CK. In comparison to the CK, tea's hundred-bud weight (BW), free amino acids (AA), tea polyphenols (TPC), and chlorophyll (Chl) content of P + C treatment got 29.98%, 14.41%, 22.49%, and 28.85% increase compared to that of the CK, respectively. In the second year, the three treatments of P, C and P + C still had significant moderating effects on the physicochemical properties of the soil and the quality indexes of the tea leaves. The PAC of the soil under the three treatments increased by 0.06%, 0.07% and 0.18%, respectively, as compared to the control.P + C increased BW, AA, TPC and Chl of tea for 2years. Three conditioners had 2-year regulatory impacts on soil fertility indicators, tea output, and quality. C and P + C both increased soil OM by 18.59% and 21.78% compared to CK in the third year, outperforming P treatment. Redundancy analysis revealed that the primary physicochemical factors influencing tea output and quality were soil OM and pH, with available phosphorus, urease, acid phosphatase, and available nitrogen following closely afterwards.

CLEM, a universal tool for analyzing structural organization in thylakoid membranes

AbstractChlorophyll (Chl) plays a crucial role in photosynthesis, functioning as a photosensitizer. As an integral component of this process, energy absorbed by this pigment is partly emitted as red fluorescence. This signal can be readily imaged by fluorescence microscopy and provides a visualization of photosynthetic activity. However, due to limited resolution, signals cannot be assigned to specific subcellular/organellar membrane structures. By correlating fluorescence micrographs with transmission electron microscopy, researchers can identify sub‐cellular compartments and membranes, enabling the monitoring of Chl distribution within thylakoid membrane substructures in cyanobacteria, algae, and higher plant single cells. Here, we describe a simple and effective protocol for correlative light‐electron microscopy (CLEM) based on the autofluorescence of Chl and demonstrate its application to selected photosynthetic model organisms. Our findings illustrate the potential of this technique to identify areas of high Chl concentration and photochemical activity, such as grana regions in vascular plants, by mapping stacked thylakoids.

Improving High Light Tolerance of Tobacco Plants: Adequate Magnesium Supply Enhances Photosynthetic Performance

High light (HL) significantly impacts plant photosynthesis. This study investigated the effects of different magnesium (Mg) levels (0, 1, 2, and 5 mol Mg plant−1; HMg0, HMg1, HMg2, and HMg5) on tobacco (Nicotiana tabacum L. cv. Cuibi No. 1) under HL (1500 μmol m−2 s−1), aiming to understand the role of Mg in mitigating the impact of HL on photosynthesis and carbon–nitrogen metabolism. Plants treated with 1 mol Mg plant−1 under 750 μmol m−2 s−1 light conditions served as the control. HL led to a reduced chlorophyll (Chl) content and inhibited the maximum photosynthetic rate (Pmax). It also decreased energy involved in photosynthetic electron transfer (ET) and electron flux to reduction end-electron acceptors at the photosystems I (PSI) acceptor side (RE) and caused photosynthetic system damage. H2O2 accumulation exacerbated membrane lipid peroxidation damage, disrupting carbon and nitrogen metabolism, and inducing antioxidant enzyme activity. HMg2 increased Chl content, stomatal conductance, intercellular CO2 concentration, and the net photosynthetic rate compared to HMg0. It enhanced ET efficiency, PSI and PSII functionality, reduced dissipated energy flux (DI), and minimized photosynthesis damage. Conversely, excessive Mg application (HMg5) decreased Pmax and PSII activity, increasing DI. Adequate Mg supply alleviated HL’s detrimental effects by enhancing Chl content and ET and RE efficiency.

Foliar Application of Chitosan (CTS), γ-Aminobutyric Acid (GABA), or Sodium Chloride (NaCl) Mitigates Summer Bentgrass Decline in the Subtropical Zone.

Creeping bentgrass (Agrostis stolonifera) is an excellent cool-season turfgrass that is widely used in urban gardening, landscaping, and golf turf. Triennial field experiments from 2017 to 2019 were conducted to investigate effects of the foliar application of chitosan (CTS), γ-aminobutyric acid (GABA), or sodium chloride (NaCl) on mitigating summer bentgrass decline (SBD) and exploring the CTS, GABA, or NaCl regulatory mechanism of tolerance to summer heat stress associated with changes in chlorophyll (Chl) loss and photosynthetic capacity, osmotic adjustment (OA), oxidative damage, and cell membrane stability. The findings demonstrated that persistent ambient high temperatures above 30 °C during the summer months of 2017, 2018, and 2019 significantly reduced the turf quality (TQ), Chl content, photochemical efficiency of PSII (Fv/Fm and PIABS), leaf relative water content, and osmotic potential (OP) but significantly increased electrolyte leakage (EL) and the accumulations of free proline, water-soluble carbohydrate (WSC), hydrogen peroxide (H2O2), and malondialdehyde (MDA). The foliar application of CTS, GABA, or NaCl could significantly alleviate SBD, as reflected by improved TQ and delayed Chl loss during hot summer months. Heat-induced declines in Fv/Fm, PIABS, the net photosynthetic rate (Pn), the transpiration rate (Tr), and water use efficiency (WUE) could be significantly mitigated by the exogenous application of CTS, GABA, or NaCl. In addition, the foliar application of CTS, GABA, or NaCl also significantly improved the accumulations of free proline and WSC but reduced the EL, OP, and H2O2 content and the MDA content in leaves of creeping bentgrass in favor of water and redox homeostasis in summer. Based on the comprehensive evaluation of the subordinate function value analysis (SFVA), the CTS had the best effect on the mitigation of SBD, followed by GABA and NaCl in 2017, 2018, and 2019. The current study indicates that the foliar application of an appropriate dose of GABA, CTS, or NaCl provides a cost-effective strategy for mitigating SBD.

Integrated multi-omic analysis reveals the carbon metabolism-mediated regulation of polysaccharide biosynthesis by suitable light intensity in Bletilla striata leaves

Bletilla striata, valued for its medicinal and ornamental properties, remains largely unexplored in terms of how light intensity affects its physiology, biochemistry, and polysaccharide formation. In this 5-month study, B. striata plants were exposed to three different light intensities: low light (LL) (5–20 μmol m−2·s−1), middle light (ML) (200 μmol m−2·s−1), and high light (HL) (400 μmol m−2·s−1). The comprehensive assessment included growth, photosynthetic apparatus, chlorophyll fluorescence electron transport, and analysis of differential metabolites based on the transcriptome and metabolome data. The results indicated that ML resulted in the highest plant height and total polysaccharide content, enhanced photosynthetic apparatus performance and light energy utilization, and stimulated carbon metabolism and carbohydrate accumulation. HL reduced Chl content and photosynthetic apparatus functionality, disrupted OEC activity and electron transfer, stimulated carbon metabolism and starch and glucose accumulation, and hindered energy metabolism related to carbohydrate degradation and oxidation. In contrast, LL facilitated leaf growth and increased chlorophyll content but decreased plant height and total polysaccharide content, compromised the photosynthetic apparatus, hampered light energy utilization, stimulated energy metabolism related to carbohydrate degradation and oxidation, and inhibited carbon metabolism and carbohydrate synthesis. Numerous genes in carbon metabolism were strongly related to polysaccharide metabolites. The katE and cysK genes in carbon metabolism were strongly related not only to polysaccharide metabolites, but also to genes involved in polysaccharide biosynthesis. Our results highlight that light intensity plays a crucial role in affecting polysaccharide biosynthesis in B. striata, with carbon metabolism acting as a mediator under suitable light intensity conditions.

Exogenous sulfur application can effectively alleviate iron deficiency yellowing in peanuts and increase pod yield

Iron deficiency yellowing is a serious and widespread problem that seriously affects plant growth and development, ultimately damaging plant yield. Sulfur is one of the essential elements for plant growth and development, and plays an important role in crop stress resistance. Iron (Fe) and sulfur (S) play a core role in the mineral nutrients required for plant metabolism, as both elements are essential for the activity of several proteins involved in basic cellular processes. This research used peanuts as materials to explore the effect of exogenous sulfur on alleviating iron deficiency and yellowing in peanuts under iron deficiency and iron enrichment levels. A two-year field experiment was conducted on windblown sandy soil to determine peanut yield, photosynthetic rate, photosynthetic pigment content, and the activity of key enzymes such as protective enzymes in leaves and roots. The results showed that the application of exogenous sulfur can increase pod yield by an average of 12.6 %-21.6 %. The application of exogenous sulfur significantly increased the migration of iron from roots to the ground, and increased the accumulation of active iron in young leaves by 42.6–73.2 %. Exogenous sulfur application increased the content of GSH in leaves, reduced the damage of Fe-deficient to leaf tissue structure, and effectively increased or maintained the accumulation of photosynthetic compounds in leaves. In addition, exogenous sulfur application at Fe-sufficient levels promoted dry matter accumulation while increasing N and S nutrient content, thereby increasing the N: S ratio. Therefore, exogenous sulfur application significantly increased the content of Chl a and Chl b in leaves, as well as the net photosynthetic rate. The application of exogenous sulfur increased the activity of SOD, POD, and CAT enzymes in roots and leaves, decreased the content of H2O2 and MDA in leaves, and reduced the rate of O.2- generation, thereby enhancing the plant's resistance to oxidative stress. This confirms that the application of exogenous sulfur and sufficient iron is of great significance in reducing iron deficiency yellowing in peanuts and improving yield.

Changes in fruit yield, biochemical attributes, and leaf minerals of different cucumber (Cucumis sativus L.) cultivars under foliar application of silicon nanoparticles.

Silicon nanoparticles (Si NPs) have an eminent role in improving plant yield through improving yield. The present study was conducted to find the effect of Si NPs on plant yield, biochemical attributes, and minerals of different cucumber cultivars. The greenhouse experiment with foliar application of Si NPs (100, 200, and 300 mg L-1) was carried out on cucumber cultivars (Emilie, Mirsoltan, Mitio, and Viola). The application of Si NPs at 300 mg L-1 led to the highest fruit yield, with a 17% increase in fruit production compared to the control. Fruit firmness differed by 31% between Emilie and Si NPs at 100 mg L-1 and Mito at 300 mg L-1. Plants experiencing Si NPs at 300 mg L-1 had the greatest chlorophyll (Chl) a+b. Compared to the other cultivars, Mito had a greater fruit yield and Chl content. The Si NPs increased TSS by 11% while lowering TA by 24% when compared to the control at 300 mg L-1. Foliar application of Si NPs reduced the value of TSS/TA. The largest value of K was reached in the Mito cultivar with Si NPs at 200 mg L-1, with a 22% increase in comparison to the control, indicating that Si NPs considerably boosted the K content. The Si NPs at 200 mg L-1 significantly increased leaf N and P in the Mito cultivar by 16 and 50%, respectively. By using agglomerative hierarchy clustering (AHC), Emilie and Mito were located in two separate clusters, whilst Viola and Mirsoltan were grouped in one cluster. In conclusion, Si NPs at 200-300 mg L-1 enhanced fruit yield, and Mito showed the highest yield when compared to other cultivars.

Plant Leaf Functional Adaptions along Urban-Rural Gradients of Jinhua City.

Environmental changes induced by urbanization may significantly alter plant survival strategies, thereby introducing uncertainties in their ability to withstand extreme heat. This study, centered on Jinhua City, distinguished urban, suburban, and rural areas to represent the various intensities of urbanization. It examined the leaf function properties of evergreen and deciduous trees common in these regions, focusing on leaf and branch characteristics. Employing an analysis of variance (ANOVA), principal component analysis (PCA), and path analysis (PA) of the plant functional traits and the climatic factors of each region, this study assessed the impact of urbanization on plant survival strategies. By tracking changes in plant functional traits from June to August, it explored the capacity of plants to acclimate to urban-warming-related heat stress across different urbanization gradients. The findings revealed that leaf thickness (LT) and stomatal size (SS) initially decreased and then increased, whereas specific leaf area (SLA) and leaf tissue density (LTD) first rose and then declined, from rural to urban regions. From June to August, branch wood density (WD), chlorophyll (Chl) content, LTD, and leaf dry matter content (LDMC) increased, whereas SLA and leaf water content (LWC) diminished, in all regions. PCA suggested that there was no significant change in the resource allocation strategy of plants (p > 0.05), with drought tolerance significantly reduced in the suburbs on the gradient of urbanization (p < 0.05). During the summer, with high temperature, plants were predominantly biased towards slow-return, conservative strategies, particularly among evergreen species. Compared to precipitation, PA revealed a significant urban warming effect. During summer, temperature was the main factor influencing resource investment strategy and drought resistance, with a notably stronger impact on the former. The high temperature in summer promoted a conservative survival strategy in plants, and the urbanization effect increased their tolerance to high temperatures.