Analysis Of Photosynthetic Pigments Research Articles

Optimization and mechanism analysis of photosynthetic EPA production in Nannochloropsis salina: Evaluating the effect of temperature and nitrogen concentrations

Microalgae, recognized as sustainable and eco-friendly photosynthetic microorganisms, play a pivotal role in converting CO2 into value-added products. Among these, Nannochloropsis salina (Microchloropsis salina) stands out, particularly for its ability to produce eicosapentaenoic acid (EPA), a crucial omega-3 fatty acid with significant health benefits such as anti-inflammatory properties and cardiovascular health promotion. This study focused on optimizing the cultivation conditions of Nannochloropsis salina to maximize EPA production. We thoroughly investigated the effects of varying temperatures and nitrogen (NaNO3) concentrations on biomass, total lipid content, and EPA proportions. We successfully identified optimal conditions at an initial NaNO3 concentration of 1.28 g.L−1 and a temperature of 21 °C. This condition was further validated by response surface methodology, which resulted in the highest EPA productivity reported in batch systems (14.4 mg.L−1.day−1). Quantitative real-time PCR and transcriptomic analysis also demonstrated a positive correlation between specific gene expressions and enhanced EPA production. Through a comprehensive lipid analysis and photosynthetic pigment analysis, we deduced that the production of EPA in Nannochloropsis salina seemed to be produced by the remodeling of chloroplast membrane lipids. These findings provide crucial insights into how temperature and nutrient availability influence fatty acid composition in N. salina, offering valuable guidance for developing strategies to improve EPA production in various microalgae species.

Anthropogenic Eutrophication Drives Major Food Web Changes in Mwanza Gulf, Lake Victoria

Discerning ecosystem change and food web dynamics underlying anthropogenic eutrophication and the introduction of non-native species is necessary for ensuring the long-term sustainability of fisheries and lake biodiversity. Previous studies of eutrophication in Lake Victoria, eastern Africa, have focused on the loss of endemic fish biodiversity over the past several decades, but changes in the plankton communities over this same time remain unclear. To fill this gap, we examined sediment cores from a eutrophic embayment, Mwanza Gulf, to determine the timing and magnitude of changes in the phytoplankton and zooplankton assemblages over the past century. Biogeochemical proxies indicate nutrient enrichment began around ~ 1920 CE and led to rapid increases in primary production, and our analysis of photosynthetic pigments revealed three zones: pre-eutrophication (prior to 1920 CE), onset of eutrophication with increases in all pigments (1920–1990 CE), and sustained eutrophication with cyanobacterial dominance (1990 CE–present). Cladoceran remains indicate an abrupt decline in biomass in ~ 1960 CE, in response to the cumulative effects of eutrophication and lake-level rise, preceding the collapse of haplochromine cichlids in the 1980s. Alona and Chydorus, typically benthic littoral taxa, have remained at relatively low abundances since the 1960s, whereas the abundance of Bosmina, typically a planktonic taxon, increased in the 1990s concurrently with the biomass recovery of haplochromine cichlid fishes. Overall, our results demonstrate substantial changes over the past century in the biomass structure and taxonomic composition of Mwanza Gulf phytoplankton and zooplankton communities, providing a historical food web perspective that can help understand the recent changes and inform future resource management decisions in the Lake Victoria ecosystem.

Impact of short-term irrigation of diverse distillery wastewater types on plant attributes and antioxidative enzymes of pea (Pisum sativum L. var. Rachna).

The study was focused on evaluating the short-term irrigation effect of three different types of distillery wastewater, i.e., untreated, primary treated, and secondary treated, on the germination, growth, photosynthetic pigments, and antioxidant enzymes of pea (Pisum sativum L. var. Rachna). The findings indicated that exposure to 50% secondary treated distillery wastewater (ST50) resulted in the maximum values for positive germination parameters of pea, including germination percentage, germination value, germination index, peak value, vigor index, speed of germination, and tolerance index. The minimum values were observed at 100% concentration of untreated wastewater (UT100). In contrast, the maximum values for various negative germination parameters, i.e., percent inhibition, seedling mortality, and germination period, were observed at UT100 and minimum at ST50. All the growth parameters studied, i.e., length of shoot, length of root and length of seedlings, fresh weight of shoot, fresh weight of root, dry weight of shoot, and dry weight of root, showed maximum values at ST50 and minimum at UT100. Photosynthetic pigment analysis also followed a similar trend. The antioxidative enzyme characterization of Pisum sativum L. var. Rachna revealed the minimum values of catalase, ascorbic peroxidase, glutathione reductase, and superoxide dismutase at ST25 (25% concentration of secondary treated distillery wastewater) and maximum values were observed at UT100.

Striking differences in frost hardiness and inability to cold acclimate in two Mougeotia species (Zygnematophyceae) from alpine and lowland habitats

AbstractZygnematophyceae, a class of freshwater green algae, exhibit distinctive seasonal dynamics. The increasing frequency of cold snaps during the growing season might challenge the persistence of some populations. The present study explored the frost hardiness of two Mougeotia species isolated from different elevations and habitats. Additionally, a phylogenetic (rbcL sequence), ultrastructural and physiological characterization was performed. Both species, grown under standard culture conditions and cold acclimated cultures (+4°C), were exposed to freezing temperatures down to −9°C. Furthermore, ultrastructural‐, hydrogen peroxide (H2O2)‐ and photosynthetic pigment analysis were performed on cells exposed to −2°C, with and without induced ice nucleation. The alpine M. disjuncta showed a higher frost hardiness (LT50 = −5.8°C), whereas the lowland M. scalaris was susceptible to ice. However, frost hardiness did not improve after cold acclimation in either species but rather decreased significantly in M. disjuncta (LT50 = −4.7°C). Despite darkness, prolonged sub‐zero temperatures or freezing induced the activation of the xanthophyll (VAZ) cycle in M. scalaris. Our results demonstrate that frost hardiness varies within the genus Mougeotia and that the VAZ cycle can be activated in the dark under subzero temperature‐ and freezing stress but does not necessarily increase frost hardiness. As highly frost hardy cell types are usually formed at the end of the growing season, the ability of young cells to survive ice formation in the upper subzero temperature range represents a crucial survival strategy in populations exposed to late spring frosts.

Biostimulants promoting growth of Vicia faba L. seedlings: inulin coated ZnO nanoparticles

In the present contribution, inulin coated ZnO nanoparticles (ZnO@inu NPs) were investigated for their potential application on crop production systems, by appraisal of their biostimulating effects on Vicia faba L (faba bean). Naked and coated ZnO NPs were synthesized according to purposely implemented eco-friendly protocols and characterized with multiple techniques to determine their crystallographic phase, average particle size, and degree of coating. Faba beans were grown in culture medium supplemented with NPs at 50 or 100 mg kg−1, using ZnO NPs alone, inulin alone, a mixture of the two, or ZnO@inu NPs. Seed germination rate and biometric evaluations on seedlings were carried out, together with Zn localization in the plant tissues. Cellular and molecular effects were ascertained by analyses of photosynthetic pigments, cytotoxicity, genotoxicity, viability, induction of oxidative stress and tissue damage, antioxidant response, and modulation of gene expression. These combined studies indicated a potential role of ZnO@inu NPs in promoting growth and development of V. faba seedlings, acting at a post-germinative phase, probably by stimulating the stem cell mitosis. Finally, inulin as a coating agent for the ZnO NPs favored the bioavailability and adsorption of the nanomaterials into the plant tissues, without altering their bioactivity but mitigating any adverse side effect.Graphical

UVB treatments of packaged ready-to-eat salads: Induced enhancement of quercetin derivatives in baby-leaf lettuce (Lactuca sativa L.) and wild rocket (Diplotaxis tenuifolia L.)

Ready-To-Eat (RTE) salads conveniently pre-prepared in bags can promote the intake of natural bioactive compounds, including antivirals such as quercetin. However, the content of these compounds in the species used for RTE salads is usually low due to limited solar UV exposure under tunnels and greenhouses in which they are usually cultivated. To address this, we treated commercial fresh-cut lettuce (Lactuca sativa L.) and wild rocket (Diplotaxis tenuifolia L.) leaves using a narrow-band UVB lamp directly through sealed polypropylene bags during storage (5–6 °C, 80% RH). The bagged leaf samples were kept under 20 µmol m−2 s−1 of white light with a 12 h photoperiod for 6 d. Half of the samples were additionally treated, 9 h d−1, during the first 3 d by UVB narrow-band lamps delivering 2.8–3.6 μmol m−2s−1 of UVB and 0.8–1.0 μmol m−2s−1 of UVA radiation. The effects of the UVB treatments on epidermal phenolics, chlorophyll and photosynthetic parameters were monitored daily by non-destructive fluorescence sensors over a 6-d storage period. At the end of the experiment, destructive HPLC-DAD analysis of phenolics and photosynthetic pigments, antioxidant capacity assays and fresh weight loss determinations were conducted. The UVB-treatment increased the epidermal phenolics (EPhen) Index with respect to unirradiated controls, while not affecting chlorophyll and carotenoids levels as well as photosynthetic efficiency. For both species, the EPhen Index changes were detected 15 h after the first UVB application. Then, wild rocket responded faster than baby-leaf lettuce and reached the maximal phenolic level with less than 1/3 of the energy dose needed by lettuce. UVB-treated samples exhibited higher flavonoid concentrations (mainly quercetin derivatives) compared to controls (48–67% and 37–66% in lettuce and wild rocket, respectively). Leaf chlorophyll and carotenoid contents were not affected by both UVB treatment and storage. We proved, for the first time, that it is possible to treat RTE salad leaves using through-packaging UVB radiation and enhance their total phenolic and quercetin derivative contents. We also provided more insights concerning the dynamics of the UVB-elicitation of phenolic compounds in postharvest leaves. Our results are propaedeutic for the optimization of potential UVB-treatments; selection of the most efficient wavelengths, intensity, single/multiple doses and proposals for application in the food industry.

A simulated drier climate reduces growth and alters functional traits of Eucalyptus trees: A three-year experiment in South China

Global climate change is triggering more occurrences of drought events, which is continuously enlarging a worldwide area of arid and semi-arid regions. South China is a typical area that suffers seasonal drought events, which reduce plantation productivity and increase tree mortality. Eucalyptus is widely cultivated in South China due to its fast growing speed and high dry mass yield, but its response to severe drought stress is still not assessed. In this study, we analyzed how a 50 % throughfall reduction (TR) and season affected stand growth, foliar gas exchange parameters, leaf stomatal morphological traits, and hydraulic conductance. Three-year observations showed that TR intensified drought stress in the dry season by decreasing soil relative water content, resulting in the diameter at breast height growth, tree height growth, and stand volume growth of TR were 12.6 %, 19.0 %, and 23.7 % lower than those of the control treatment (CK), respectively. With the continuous drought, TR decreased the net photosynthetic rate, while having little effect on the transpiration rate and water use efficiency. Photosynthetic pigment analysis revealed a significant interaction between throughfall reduction and season, TR markedly decreased photosynthetic pigments during the wet season. Hydraulic conductivity declined by TR, which primarily existed during the dry season. To limit water loss, Eucalyptus adapted to drought stress by altering these functional traits, which were not entirely consistent with the drought resistance mechanisms of other tree species. Overall, our study indicated that the simulated drier climate included growth decline and variation in functional traits of Eucalyptus trees in South China. This study is important for understanding the drought resistance mechanisms of Eucalyptus, as well as predicting the risk of declining Eucalyptus timber production owing to global climate change.

Synergistic effects of warming and low salinity enhanced the production of Gracilariopsis lemaneiformis in the warming drainage zone of Tianwan Nuclear Power Plant, China

Tianwan Nuclear Power Plant in China is the world's largest coastal nuclear power plant in terms of its total installed capacity both in operation and under construction. Its operations create a warming drainage zone that is potentially beneficial to the large-scale cultivation of macroalgae. Moreover, natural freshwater river flow and ocean acidification caused by increasing levels of atmospheric CO2 bring new uncertainties to the growth and photophysiology of commercial macroalgae. In this study, two CO2 concentrations (LC, 400 μatm; HC, 1000 μatm), two salinity levels (LS, 20 ppt; HS, 30 ppt), and two temperatures (LT, 20 °C; HT, 26 °C) were tested to examine the synergistic effects of warming and salinity on the economically important macroalga Gracilariopsis lemaneiformis under ocean acidification. The results showed that the synergistic effect of LS and HT treatments significantly promoted the growth of G. lemaneiformis under LC treatment, but this promotion effect was more obvious under HC treatment. In contrast, HSLT conditions inhibited G. lemaneiformis growth under both LC and HC conditions. Under HC treatment, warming and low salinity together increased the maximum photosynthetic rate and the maximum electron transport rate of G. lemaneiformis. Photosynthetic pigment analysis revealed that LS had a significantly negative effect on the contents of chlorophyll a (Chl a) and carotenoids (Car.), and HT had an obviously adverse influence on the contents of Chl a, Car., phycoerythrin, and phycocyanin. Moreover, the dual limitation of LSHT conditions significantly reduced the contents of Chl a and Car. under HC and LC conditions. These findings suggested that warming and low salinity synergically improved the growth and photosynthetic performance of G. lemaneiformis, especially under ocean acidification. The results provide a scientific basis for macroalgal cultivation as part of environmental restoration around nuclear power plants generally and year-round cultivation of G. lemaneiformis in northern China specifically.

Evaluation of the physiological parameters in Lavandula latifolia Medik. under water deficit for preselection of elite drought-resistant plants

Lavandula latifolia Medik. is an aromatic-medicinal plant, native to the Mediterranean region, for which economic interest is mainly focused on the production of essential oil. In the Mediterranean area, the negative effects of climate change, with increasingly frequent extreme heatwaves and drought episodes, have led to the need to select plants with greater tolerance of such scenarios for the future development of this rainfed crop. In the current study, young plants of spike lavender were subjected to a first episode of water deprivation. Subsequently, clones from the surviving ecotypes (SL1 to SL8) were assigned randomly to two homogeneous groups. One group was irrigated to field capacity (as a control) and the other was subjected to water stress for two months. In the leaves of control and stressed plants, physiological parameters including relative water content (%RWC), hydric potential (ΨWP), proline, and abscisic acid were measured. The plant antioxidant defense system was also explored, through analysis of non-enzymatic antioxidants (α-tocopherol, plastochromanol-8), lipid peroxidation (MDA), and photosynthetic pigments (chlorophylls a and b, and carotenoids). The polyphenolic profile was determined and its corresponding antioxidant activity was analyzed for the first time in the early growth stages of this species. Under the drought treatment, the values of the physiological parameters were similar in all ecotypes and changed as the dehydration advanced. However, the response of the antioxidant defense to drought was variable depending on the ecotype under study. As a general pattern, there was a reduction in the concentration of photosynthetic pigments. Although, no statistical differences were detected in α-tocopherol and PC-8, in most cases, the MDA values increased significantly after the drought episode. In the polyphenolic profile identified, p-coumaric acid glycoside and rosmarinic acid-3–O-glucoside were the major components quantified, salvianic acid and O-coumaric acid being described for the first time in this species. Regarding the response of these chemical components to water stress, the concentrations of most polyphenols decreased, with the exception of rosmarinic acid, whose concentration after the stress was higher in three of the eight ecotypes under study. This increment was reflected in a higher in vitro antioxidant capacity. These findings suggest that L. latifolia was affected by drought, even though it showed some strategies to counteract the negative effects of dehydration. The intraspecific variation in the response to dehydration can be considered a useful tool for the preselection of ecotypes with greater resistance to this stress.

Effect of Moisture Stress on Physiological and Yield Responses of Common Bean Varieties at Lath House Condition, Hawassa University, Southern Ethiopia

Common bean is one of the most traditional foods, with social and economic importance, and is suitable for food security due to its short growing cycle and adaptability to different cropping systems. However, various constraints like biotic and abiotic factors reported for the low productivity of the crop. Therefore, the study was designed to identify the common bean varieties’ response on physiological properties and yield performance under different irrigation intervals in Lath House condition at Hawassa University, Ethiopia, from June, 2020, to September, 2020. The experiment was laid out in a completely randomized design with a factorial combination of seven common bean varieties (Awash-1, Awash-2, Dursitu, Fedis, Gofta, Nasir, and Tinike) and three moisture levels, eight day irrigation interval, four day irrigation interval, and daily watering with three replication. There was a significant main and interaction effects among the measured parameters. From those significantly affected parameters, the highest stomata numbers (25) were recorded from the Dursitu variety with a daily irrigation interval. The longest stomata aperture was observed with Gofta (133.76 nm) and Fedis varieties (131.13 nm) to daily irrigation and four day irrigation intervals, respectively. A wider stomata aperture was found in the Awash-1(12.6 nm) variety on a daily irrigation interval, and maximum stomata conductance (193.67) was obtained in the Tinike variety treated with a four day irrigation interval. The maximum relative leaf moisture content (96%) was found on the Awash-1 variety at a four day irrigation interval. Maximum water use efficiency was obtained from the Awash-1 (3.95) variety, which is an insignificant variation with the Awash-2 (3.85) and Gofta varieties (3.85) at a four day irrigation interval. Among the varieties, the highest photosynthesis rate (10.43 μmol·m−2·s−1) and transpiration rate (5.42 mmol·m−2·s−1) were obtained in the Gofta variety treated by a four day irrigation interval. In the photosynthetic pigment analysis, the highest leaf chl-a, chl-b, and chl-a + b concentration was recorded at 2.4 μg/ml, 1.53 g/ml, and 3.93 μg/ml, respectively, in the Gofta variety irrigated at a four days interval. The highest (0.586) chlorophyll fluorescence was obtained in the eight day irrigation interval. The highest proline content was found from the Awash-1 (0.78) variety regarding to drought stress condition. The highest pods plant−1 (9) and seed pod−1 (5) was found in the Awash-2 and Awash-1 varieties, respectively, at a four days irrigation interval and the highest main effect of 100 SW (39.48 g), (28.6 g) was found in the Fedis variety and at a four day irrigating interval, respectively. The maximum yield was obtained from the varieties Awash-1 (7.8 g plant−1) and Gofta (7.36 g plant−1) with a four day irrigated interval and they are also superior at drought condition and Awash-2 varieties are enhanced at waterlogging condition as compared to the other varieties.

Phenotyping of basil (Ocimum basilicum L.) illuminated with UV-A light of different wavelengths and intensities

The effects of light on plants depend on the energy dose and spectral characteristics. We investigated how UV-A radiation with two different wavelengths, 365 and 385 nm, combined at different intensities as supplemental light to red-blue baseline illumination affects growth and selected physiological and biochemical traits of green leaf basil (Ocimum basilicum L.). Conventional physiological measurements and biochemical analyses of photosynthetic pigments and phenolics were combined with high-throughput phenotyping. We did not detect any negative effects of UV-A on plant growth and photosynthetic functions, even at high doses of short-wave UV-A. Furthermore, thylakoid processes were enhanced under UV-A, as evidenced by higher electron transport rates and increased photochemical efficiency. The increase in anthocyanin index (ARI) indicates the UV-screening response. However, no anthocyanins were detected in the leaves, and the only phenolic compounds that responded to UV-A were hydroxycinnamic acid derivatives, which have a dual function in responding to UV-A (UV protection and antioxidants). UV-A increased the pool of xanthophyll cycle pigments and their ratio to chlorophylls. All this prevents photoinhibition and contributes to a high plasticity/efficiency of the basil's response to light environment.

Combination of long-term 13CO2 labeling and isotopolog profiling allows turnover analysis of photosynthetic pigments in Arabidopsis leaves

BackgroundLiving cells maintain and adjust structural and functional integrity by continual synthesis and degradation of metabolites and macromolecules. The maintenance and adjustment of thylakoid membrane involve turnover of photosynthetic pigments along with subunits of protein complexes. Quantifying their turnover is essential to understand the mechanisms of homeostasis and long-term acclimation of photosynthetic apparatus. Here we report methods combining whole-plant long-term 13CO2 labeling and liquid chromatography - mass spectrometry (LC–MS) analysis to determine the size of non-labeled population (NLP) of carotenoids and chlorophylls (Chl) in leaf pigment extracts of partially 13C-labeled plants.ResultsThe labeling chamber enabled parallel 13CO2 labeling of up to 15 plants of Arabidopsis thaliana with real-time environmental monitoring ([CO2], light intensity, temperature, relative air humidity and pressure) and recording. No significant difference in growth or photosynthetic pigment composition was found in leaves after 7-d exposure to normal CO2 (~ 400 ppm) or 13CO2 in the labeling chamber, or in ambient air outside the labeling chamber (control). Following chromatographic separation of the pigments and mass peak assignment by high-resolution Fourier-transform ion cyclotron resonance MS, mass spectra of photosynthetic pigments were analyzed by triple quadrupole MS to calculate NLP. The size of NLP remaining after the 7-d 13CO2 labeling was ~ 10.3% and ~ 11.5% for all-trans- and 9-cis-β-carotene, ~ 21.9% for lutein, ~ 18.8% for Chl a and 33.6% for Chl b, highlighting non-uniform turnover of these pigments in thylakoids. Comparable results were obtained in all replicate plants of the 13CO2 labeling experiment except for three that were showing anthocyanin accumulation and growth impairment due to insufficient water supply (leading to stomatal closure and less 13C incorporation).ConclusionsOur methods allow 13CO2 labeling and estimation of NLP for photosynthetic pigments with high reproducibility despite potential variations in [13CO2] between the experiments. The results indicate distinct turnover rates of carotenoids and Chls in thylakoid membrane, which can be investigated in the future by time course experiments. Since 13C enrichment can be measured in a range of compounds, long-term 13CO2 labeling chamber, in combination with appropriate MS methods, facilitates turnover analysis of various metabolites and macromolecules in plants on a time scale of hours to days.

Physiological responses of Amaranthus cruentus L. to drought stress under sufficient- and deficient-nitrogen conditions.

Water and nitrogen availability are two major environmental factors that can impair plant growth, and when combined, their effects on plant performance can be either intensified or reduced. The objective of this study was to analyze the influence of nitrogen availability on the responses of Amaranthus cruentus’s metabolism to water stress. The plants were cultivated in plastic pots filled with vermiculite, kept under greenhouse conditions, and were watered three times a week with 70% of a full strength nitrogen-free Long Ashton solution, containing 1.97 or 9.88 kg N ha−1 as ammonium nitrate. Photosynthetic parameters were evaluated in planta, and leaves were harvested for chemical analysis of photosynthetic pigments, proline, and phenolic contents. Higher nitrogen supply increased the shoot dry matter, photosynthetic pigments, photosynthesis, stomatal conductance, transpiration, total leaf nitrogen, proline, nitrate, and ammonium but reduced the concentration of flavonoids and total phenols. Six days of water stress did not affect dry matter, photosynthetic pigments, leaf nitrogen, ammonium, or specialized metabolites but increased the proline under high nitrogen and negatively affected stomatal conductance, transpiration, photosynthesis, relative water content, instantaneous water use efficiency, and leaf nitrate. The negative effect was more pronounced under high nitrogen supply. The results show that the addition of a high amount of nitrogen made the physiological processes of plants more sensitive to water stress, indicating that the plant response to water restriction depends on the interaction between the different environmental stressors to which the plants are subjected.

Spectral technology and multispectral imaging for estimating the photosynthetic pigments and SPAD of the Chinese cabbage based on machine learning

• The estimation models constructed by spectra and multispectral imaging combined with various machine learning algorithms were compared. • A one-dimensional convolutional neural network model based on spectral data was established. • A two-dimensional convolutional neural network model based on multispectral images was established. • Spectra and multispectral images were combined with deep learning to achieve the estimation of multiple indicators, such as photosynthetic pigments and SPAD. The contents of photosynthetic pigment, which directly affect the growth of crops, could be evaluated with spectral and multispectral imaging technologies in an accurate and rapid way. For commodity germplasm resources on the market, the estimation of photosynthetic pigments and soil and plant analyzer development (SPAD) value was accomplished using the two techniques combined with machine learning. The spectrometer used in this study employed 781 bands from 320 nm to 1100 nm, and a multispectral imaging camera was used to acquire images in visible and near-infrared. Convolutional neural network (CNN), multiple linear regression (MLR) and generalized linear model (GLM) were used to establish the machine learning models, which established by preprocessed spectral data or 4-channel multispectral images. For estimating photosynthetic pigments (chlorophyll a , chlorophyll b , total chlorophyll and carotenoids), the GLM model established by spectral data was the optimal among all the models. For the SPAD optimal estimation model, the GLM model established by the spectral data and CNN model established by the multispectral images were fair. The R 2 and RMSE of the CNN model validation set in estimating SPAD were 0.87 and 2.31, respectively. The R 2 and RMSE of the GLM model validation set in estimating SPAD were 0.88 and 2.39, respectively. By combining two techniques with different machine learning methods, a comprehensive analysis of photosynthetic pigments and SPAD was accomplished in this paper.

Sustainable synthesis of microwave-assisted IONPs using Spinacia oleracea L. for control of fungal wilt by modulating the defense system in tomato plants

BackgroundChanging climate enhances the survival of pests and pathogens, which eventually affects crop yield and reduces its economic value. Novel approaches should be employed to ensure sustainable food security. Nano-based agri-chemicals provide a distinctive mechanism to increase productivity and manage phytopathogens, with minimal environmental distress. In vitro and in greenhouse studies were conducted to evaluate the potential of green-synthesized iron-oxide nanoparticles (IONPs) in suppressing wilt infection caused by Fusarium oxysporum f. sp. lycospersici, and improving tomato growth (Solanum lycopersicum) and fruit quality.ResultsVarious microwave powers (100–1000 W) were used to modulate the properties of the green-synthesized IONPs, using spinach as a starting material. The IONPs stabilized with black coffee extract were substantively characterized using X-ray diffraction analysis (XRD), Fourier-transform infrared spectroscopy, dielectric and impedance spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning and transmission electron microscopy (SEM and TEM, respectively), and magnetization analysis. XRD revealed a cubic magnetite (Fe3O4) phase with super-paramagnetic nature, detected at all microwave powers. The binding energies of Fe 2p3/2 (710.9 eV) and Fe 2p1/2 (724.5 eV) of Fe3O4 NPs were confirmed using XPS analysis at a microwave power of 1000 W. Uniform, spherical/cubical-shaped particles with an average diameter of 4 nm were confirmed using SEM and TEM analysis. A significant reduction in mycelial growth and spore germination was observed upon exposure to different IONP treatments. Malformed mycelium, DNA fragmentation, alternation in the cell membrane, and ROS production in F. oxysporum indicated the anti-microbial potential of the IONPs. The particles were applied both through the root (before transplantation) and by means of foliar application (after two weeks) to the infected seedlings. IONPs significantly reduced disease severity by an average of 47.8%, resulting in increased plant growth variables after exposure to 12.5 µg/mL of IONPs. Analysis of photosynthetic pigments, phenolic compounds, and anti-oxidant enzymes in the roots and shoots showed an increasing trend after exposure to various concentrations of IONPs. Correspondingly, lycopene, vitamin C, total flavonoids, and protein content were substantially improved in tomato fruits after treatment with IONPs.ConclusionThe findings of the current investigation suggested that the synthesized IONPs display anti-fungal and nutritional properties that can help to manage Fusarium wilt disease, resulting in enhanced plant growth and fruit quality.Graphical

Comparative transcriptome and physiological analyses reveal key factors in the tolerance of peach rootstocks to iron deficiency chlorosis.

The online version contains supplementary material available at 10.1007/s13205-021-03046-6.

COMPARATIVE STUDY ON THE EFFECTS OF WHEAT PLANTS EXPOSURE TO GIBBERELLIC ACID AND SALICYLIC ACID

We set out to characterize some aspects of growth and metabolism of wheat seedlings that have grown for 7 days on media supplemented with gibberellic acid (GA3) or salicylic acid (SA), at concentrations of 10 μmol∙L-1 and 100 μmol∙L-1. Compared to control plants, increased concentration of glucose and lipid peroxidation products were observed in GA3 series, while higher levels of soluble proteins, glucose, acid phosphatase and peroxidase activity were measured in SA series. Data from photosynthetic pigment analysis pointed out minor differences regarding chlorophylls and carotenoids content in plants’ leaves, both within and between the groups. Although total carotenoid content didn’t vary markedly among the experimental variants, certain changes of the relative contribution of the pigments in the carotenoid pool were observed, mainly a decrease of neoxanthin content paralleled by an increase of violaxanthin content. However, as the biometric data have shown, plant growth was neither inhibited nor stimulated, irrespective of the growth conditions. The observed modulation of certain biochemical parameters may be considered as part of the plants’ adaptive responses to an environmental challenge, where the differences between GA3 and SA regarding bioavailability, mobility and specific mechanisms of action underlie the different outcomes.

COMPARATIVE STUDY ON THE EFFECTS OF WHEAT PLANTS EXPOSURE TO GIBBERELLIC ACID AND SALICYLIC ACID

We set out to characterize some aspects of growth and metabolism of wheat seedlings that have grown for 7 days on media supplemented with gibberellic acid (GA3) or salicylic acid (SA), at concentrations of 10 μmol∙L-1 and 100 μmol∙L-1. Compared to control plants, increased concentration of glucose and lipid peroxidation products were observed in GA3 series, while higher levels of soluble proteins, glucose, acid phosphatase and peroxidase activity were measured in SA series. Data from photosynthetic pigment analysis pointed out minor differences regarding chlorophylls and carotenoids content in plants’ leaves, both within and between the groups. Although total carotenoid content didn’t vary markedly among the experimental variants, certain changes of the relative contribution of the pigments in the carotenoid pool were observed, mainly a decrease of neoxanthin content paralleled by an increase of violaxanthin content. However, as the biometric data have shown, plant growth was neither inhibited nor stimulated, irrespective of the growth conditions. The observed modulation of certain biochemical parameters may be considered as part of the plants’ adaptive responses to an environmental challenge, where the differences between GA3 and SA regarding bioavailability, mobility and specific mechanisms of action underlie the different outcomes.

Identification of the key functional genes in salt-stress tolerance of Cyanobacterium Phormidium tenue using in silico analysis.

The online version contains supplementary material available at 10.1007/s13205-021-03050-w.

Occurrence of the Freshwater Chrysophyte Poterioochromonas malhamensis in a High Arctic Marine Ecosystem

Kongsfjorden is a small Arctic fjord but with great hydrographic complexity and has changed greatly due to the climate change. Arctic warming has increased melts of sea ice and glaciers that results in higher freshwater content. Microbial community variability and increasing terrestrial input were detected continuously in recent years ITag eukaryotic 18S rRNA V4 metabarcoding, photosynthetic pigments analysis and epifluorescence microscopy were used to reveal the dominant species of small eukaryotic community (<20 μm). Both Spearman correlation and redundant analysis were used to study the correlation between the small eukaryotes and the environmental conditions. In the present study, the surface water with salinity lower than 34 was thicker than in summers of previous years. The freshwater mixotrophic chrysophyte Poterioochromonas malhamensis was found for the first time as the dominant species. No general trends were found for the contributions of P. malhamensis to the total reads of small eukaryotes in water depths; and no obvious differences were found at different stations and water masses. Phagotrophy, which is more common than phototrophy at all times in P. malhamensis, is thought to be the main reason for the prevalence of P. malhamensis in Kongsfjorden. The occurrence of P. malhamensis induced a disorder in the small eukaryotic community, which biodiversity and composition showed weak correlation with the water masses. The dominance of the freshwater-originating phytoplankton may indicate an ecosystem change in the Kongsjforden, which probably might become more remarkable in the future as the climate continues to change.