Mycorrhizal fungi reduce the photosystem damage caused by drought stress on Paris polyphylla var. yunnanensis.

Drought stress (DS) is one of the important abiotic stresses facing cash crops today. Drought can reduce plant growth and development, inhibit photosynthesis, and thus reduce plant yield. In this experiment, we investigated the protective mechanism of AMF on plant photosynthetic system by inoculating Paris polyphylla var. yunnanensis(P.py) with a clumping mycorrhizal fungus (AMF) under drought conditions. The drought environment was maintained by weighing AMF plants and non-AMF plants. The relative water content (RWC) of plant leaves was measured to determine its drought effect. DS decreased the RWC of plants, but AMF was able to increase the RWC of plants. chlorophyll a fluorescence curve measurements revealed that DS increased the OKJIP curve of plants, but AMF was able to reduce this trend, indicating that AMF increased the light absorption capacity of plants. DS also caused a decrease in plant Y(I) and Y(II). ETRI and ETRII, and increased Y(NO) and Y(NA) in plants, indicating that DS caused photosystem damage in plants. For the same host, different AMFs did not help to the same extent, but all AMFs were able to help plants reduce this damage and contribute to the increase of plant photosynthesis under normal water conditions.

Ecotoxicological assessment of cigarette butts on morphology and photosynthetic potential of Azolla pinnata.

Cigarette butts (CBs) have become the most ubiquitous form of anthropogenic litter globally. CBs contain various hazardous chemicals that persist in the environment for longer period. These substances are susceptible to leaching into the environment through waterways. The recent study was aimed to evaluate the effects of disposed CBs on the growth and development of Azolla pinnata, an aquatic plant. It was found that after a span of 6 days, the root length, surface area, number of fronds, and photosynthetic efficacy of plant were considerably diminished on the exposure of CBs (concentrations 0 to 40). The exposure of CBs led to a decrease in the FM, FV/F0, and φP0, in contrast, the φD0 increased in response to CBs concentration. Moreover, ABS/CSm, TR0/CSm, and ET0/CSm displayed a negative correlation with CB-induced chemical stress. The performance indices were also decreased (p-value ≤ 0.05) at the highest concentration of CBs. LD50 and LD90 represent the lethal dose, obtained value for LD50 is 20.30 CBs and LD90 is 35.26 CBs through probit analysis. Our results demonstrate that the CBs cause irreversible damage of photosynthetic machinery in plants and also reflect the efficacy of chlorophyll a fluorescence analysis and JIP test for assessing the toxicity of CBs in plants.

Exploring the synergistic effects of indole acetic acid (IAA) and compost in the phytostabilization of nickel (Ni) in cauliflower rhizosphere.

Heavy metals (HMs) contamination, owing to their potential links to various chronic diseases, poses a global threat to agriculture, environment, and human health. Nickel (Ni) is an essential element however, at higher concentration, it is highly phytotoxic, and affects major plant functions. Beneficial roles of plant growth regulators (PGRs) and organic amendments in mitigating the adverse impacts of HM on plant growth has gained the attention of scientific community worldwide. Here, we performed a greenhouse study to investigate the effect of indole-3-acetic acid (IAA @ 10- 5 M) and compost (1% w/w) individually and in combination in sustaining cauliflower growth and yield under Ni stress. In our results, combined application proved significantly better than individual applications in alleviating the adverse effects of Ni on cauliflower as it increased various plant attributes such as plant height (49%), root length (76%), curd height and diameter (68 and 134%), leaf area (75%), transpiration rate (36%), stomatal conductance (104%), water use efficiency (143%), flavonoid and phenolic contents (212 and 133%), soluble sugars and protein contents (202 and 199%), SPAD value (78%), chlorophyll 'a and b' (219 and 208%), carotenoid (335%), and NPK uptake (191, 79 and 92%) as compared to the control. Co-application of IAA and compost reduced Ni-induced electrolyte leakage (64%) and improved the antioxidant activities, including APX (55%), CAT (30%), SOD (43%), POD (55%), while reducing MDA and H2O2 contents (77 and 52%) compared to the control. The combined application also reduced Ni uptake in roots, shoots, and curd by 51, 78 and 72% respectively along with an increased relative production index (78%) as compared to the control. Hence, synergistic application of IAA and compost can mitigate Ni induced adverse impacts on cauliflower growth by immobilizing it in the soil.

The long noncoding RNA LAL contributes to salinity tolerance by modulating LHCB1s' expression in Medicago truncatula.

Long non-coding RNAs (lncRNAs) are abundant in plants, however, their regulatory roles remain unclear in most biological processes, such as response in salinity stress which is harm to plant production. Here we show a lncRNA in Medicago truncatula identified from salt-treated Medicago truncatula is important for salinity tolerance. We name the lncRNA LAL, LncRNA ANTISENSE to M. truncatula LIGHT-HARVESTING CHLOROPHYLL A/B BINDING (MtLHCB) genes. LAL is an antisense to four consecutive MtLHCB genes on chromosome 6. In salt-treated M. truncatula, LAL is suppressed in an early stage but induced later; this pattern is opposite to that of the four MtLHCBs. The lal mutants show enhanced salinity tolerance, while overexpressing LAL disrupts this superior tolerance in the lal background, which indicates its regulatory role in salinity response. The regulatory role of LAL on MtLHCB1.4 is further verified by transient co-expression of LAL and MtLHCB1.4-GFP in tobacco leaves, in which the cleavage of MtLHCB1.4 and production of secondary interfering RNA is identified. This work demonstrates a lncRNA, LAL, functioning as a regulator that fine-tunes salinity tolerance via regulating MtLHCB1s' expression in M. truncatula.

Modulating cultivation regimes of Messastrum gracile SVMIICT7 for biomass productivity integrated with resource recovery via hydrothermal liquefaction.

The present study was designed to assess Messastrum gracile SVMIICT7 potential in treating dairy wastewater (autoclaved (ADWW) and raw (DWW)) with relation to nutrient removal, in-vivo Chl-a-based biomass, and bio-oil synthesis. Chlorophyll a fluorescence kinetics revealed improved photochemical efficiency (0.639, Fv/Fm) in M. gracile when grown with DWW. This may be owing to enhanced electron transport being mediated by an effective water-splitting complex at photosystem (PSII) of thylakoids. The increase in ABS/RC observed in DWW can be attributed to the elevated chlorophyll content and reduced light dissipation, as evident by higher values of ETo/RC and a decrease in non-photochemical quenching (NPQ). M. gracile inoculated in DWW had the highest Chl-a-biomass yield (1.8 g L-1) and biomolecules while maximum nutrient removal efficiency was observed in ADWW (83.7% TN and 60.07% TP). M. gracile exhibited substantial bio-oil yield of 29.6% and high calorific value of 37.19 MJ kg-1, predominantly composed of hydrocarbons along with nitrogen and oxygen cyclic compounds. This research offers a thorough investigation into wastewater treatment, illustrating the conversion of algal biomass into valuable energy sources and chemical intermediates within the framework of a biorefinery.

Unveiling the Chemical Composition, Bioactive Profile and Antioxidant Capacity of Dried Egyptian Jew's Mallow Stems as a Promising Anticancer Agent.

Phytochemicals from waste materials generated by agricultural and industrial processes have become globally significant due to their accessibility and potential effectiveness with few side effects. These compounds have essential implications in both medicine and the economy. Therefore, a quantitative analysis of the phytochemical profile, sugar types, and water-soluble vitamins of dried Corchorus olitorius L."DJMS" extract (dried Jew's mallow stem) was carried out with HPLC. In addition, the chemical composition, TPC, chlorophyll a and b, beta-carotene, and antioxidant effect using DPPH were investigated. Furthermore, the anticancer activity of the DJMS was evaluated by SRB assay using Huh-7 and MDA-MB-231 cell lines. In the quantitative study, DJMS extract showed a high antioxidant potential (67%) due to its content of bioactive compounds such as TPC (276.37 mg 100 g-1) and chlorophyll a and b (20.31, 12.02 mg 100 g-1, respectively), as well as some vitamins and minerals such as B-complex (B12; 146.8 mg 100 g-1 and vitamin C 6.49 mg 100 g-1) and selenium (<0.2 µg kg-1). Moreover, the main sugar types found were sucrose and stachyose, which recorded 9.23 and 6.25 mg 100 g-1, respectively. Identifying phenolic and flavonoids showed that the major components were ellagic acid (4905.26 µg kg-1), ferulic acid (3628.29 µg kg-1), chlorogenic acid (3757.08 µg kg-1), luteolin-7-O-glucoside (4314.48 µg kg-1), naringin (4296.94 µg kg-1) and apigenin-6-rhamnose-8 glucoside (3078.87 µg kg-1). The dried stem extract showed significant MDA-MB-231 inhibition activity and reached 80% at a concentration of 1000 µg/mL of DJMS extract, related to the content of phytochemical components such as isoflavones like genistein (34.96 µg kg-1), which had a tremendous anticancer effect. Hence, the stem of Jew's mallow (which is edible and characterized by its viability and low production cost) possesses the capacity to serve as a pharmaceutical agent for combating cancer owing to its abundance of bioactive components.

Effect of cadmium on polystyrene transport in parsley roots planted in a split-root system and assessment of the combined toxic effects.

Micro and nanoplastics (MPs/NPs) coupled with heavy metals are prevalent in both aquatic and terrestrial ecosystems. Their ecological toxicity and combined adverse effects have obtained significant concern. Past studies primarily focused on how MPs/NPs influence the behavior of heavy metals. Yet, the possible effects of heavy metals on MP/NP transport and toxicity within co-contaminated systems are still not well-understood. In this study, we conducted split-root experiments to explore the transport and toxicity of polystyrene (PS) particles of varying sizes in parsley seedlings, both with and without the addition of cadmium (Cd). Both the PS-NPs (100 nm) and PS-MPs (300 nm) traveled from the PS-spiked roots (Roots-1) to the non-PS-spiked roots (Roots-2), with or without Cd, possibly because of phloem transport. Furthermore, the presence of Cd reduced the accumulation and movement of PS-NP/MP in the roots, likely due to the increased positive charge (Cd2+) on the PS surface. PS-NPs/MPs in both Roots-1 and Roots-2 were observed using transmission electron microscopy (TEM). When Cd was added to either Roots-1 (PS + Cd|H) or Roots-2 (PS|Cd), there was a minor reduction in the chlorophyll a and carotenoids content in leaves with PS|H. The adverse impacts of MPs|H on both indicators were influenced by the MP concentration. However, chlorophyll b significantly increased in the PS|H, PS + Cd|H, and PS|Cd treatments. Consequently, the chlorophyll a/b ratio declined, indicating inhibition of photosynthesis. The dehydrogenase content showed a minor change in Roots-1 and Roots-2 without Cd stress, whereas it significantly decreased on the Cd-spiked side and subsequently inhibited root growth. In contrast, the marked rise in glutathione (GSH) levels within Cd-spiked roots suggested, based on Gaussian analysis, that GSH and Cd chelation were instrumental in mitigating Cd toxicity. When Cd was introduced to both Roots-1 and Roots-2 simultaneously (PS + Cd|Cd), the aforementioned index showed a notable decline.

Effects of pulsed Nd:YAG laser kernel irradiation on maize (Zea mays L.): Insights into germination, gas exchange, photosynthetic pigments, and morphological modifications.

Energy has always been the most concerned topic worldwide due to its large consumption. Among various types of energies, light has amazing characteristics and have interesting effects on living organisms. Interest is increasing in the use of laser kernel treatment as an environment friendly physical technique for better results in agronomic crops, but the work is still in progress. The present study was conducted with the aim to examine the application of range of Neodymium-doped Yttrium Aluminum Garnet (Nd:YAG) pulsed laser exposures (200, 400, 600, 800, 1000, 1200, 1400 J/cm2) as pre-sowing kernel treatment on seedling survival rate, leaf photosynthetic activity in relation with photosynthetic pigments and visual morphological effects at seedling to maturity stage. Results showed that the low laser exposure (200, 400 and 600 J/cm2) improved the photosynthetic activity in parallel with improvement in chlorophyll a, chlorophyll b, total chlorophyll, carotenoids as well as morphological traits. Kernel treatments with higher laser fluences (800, 1000, 1200 and 1400 J/cm2) showed irregular responses in studied attributes examined at the individual plant level. At 800 and 1000 J/cm2 improvements were found in some plants but at higher doses clear negative impacts were recorded on studied attributes. In conclusion, the lower doses of Nd:YAG pulsed laser fluences are found beneficial for induction of improvement in maize plants for better growth but higher doses were found toxic ones. In future further studies are needed to check the impacts of low laser doses on yield related attributes under field conditions and the high doses might also be used to create variants with beneficial characteristics if possible.

Exogenous glutathione protected wheat seedling from high temperature and water deficit damages.

High temperatures (HT) and drought are two major factors restricting wheat growth in the early growth stages. This study investigated the role of glutathione (GSH) amendment (0.0, 0.5, 1.0, and 2.0 mM) to soil in mitigating the adverse effect of HT (33 °C, with 25 °C as a control), water regimes (60% of field capacity and control), and their combinations. HT decreased the length, project area, surface area, volume, and forks of the root, while drought had the reverse effect. Shoot length, leaf area, leaf relative water content, and shoot and root dry matter were significantly decreased by HT and drought, and their combined impact was more noticeable. GSH significantly promoted the root system, shoot growth, and leaf relative water content. The combined treatment reduced chlorophyll a, chlorophyll b, and total chlorophyll. However, 0.5 mM GSH raised chlorophyll a, chlorophyll b, and total chlorophyll by 28.6%, 41.4%, and 32.5%, respectively, relative to 0.0 mM GSH. At combined treatment, 0.5 mM GSH decreased malondialdehyde (MDA) by 29.5% and increased soluble protein content by 24.1%. GSH meaningfully enhanced the activity of superoxide dismutase, catalase, and ascorbate peroxide in different treatments. This study suggested that GSH could protect wheat seedlings from the adverse effects of HT and/or drought stresses.

Mitigation of cadmium-induced stress in maize via synergistic application of biochar and gibberellic acid to enhance morpho-physiological and biochemical traits.

Cadmium (Cd), being a heavy metal, tends to accumulate in soils primarily through industrial activities, agricultural practices, and atmospheric deposition. Maize, being a staple crop for many regions, is particularly vulnerable to Cd contamination, leading to compromised growth, reduced yields, and potential health risks for consumers. Biochar (BC), a carbon-rich material derived from the pyrolysis of organic matter has been shown to improve soil structure, nutrient retention and microbial activity. The choice of biochar as an ameliorative agent stems from its well-documented capacity to enhance soil quality and mitigate heavy metal stress. The study aims to contribute to the understanding of the efficacy of biochar in combination with GA3, a plant growth regulator known for its role in promoting various physiological processes, in mitigating the adverse effects of Cd stress. The detailed investigation into morpho-physiological attributes and biochemical responses under controlled laboratory conditions provides valuable insights into the potential benefits of these interventions. The experimental design consisted of three replicates in a complete randomized design (CRD), wherein soil, each containing 10 kg was subjected to varying concentrations of cadmium (0, 8 and 16 mg/kg) and biochar (0.75% w/w base). Twelve different treatment combinations were applied, involving the cultivation of 36 maize plants in soil contaminated with Cd (T1: Control (No Cd stress; T2: Mild Cd stress (8 mg Cd/kg soil); T3: Severe Cd stress (16 mg Cd/kg soil); T4: 10 ppm GA3 (No Cd stress); T5: 10 ppm GA3 + Mild Cd stress; T6: 10 ppm GA3 + Severe Cd stress; T7: 0.75% Biochar (No Cd stress); T8: 0.75% Biochar + Mild Cd stress; T9: 0.75% Biochar + Severe Cd stress; T10: 10 ppm GA3 + 0.75% Biochar (No Cd stress); T11: 10 ppm GA3 + 0.75% Biochar + Mild Cd stress; T12: 10 ppm GA3 + 0.75% Biochar + Severe Cd stress). The combined application of GA3 and BC significantly enhanced multiple parameters including germination (27.83%), root length (59.53%), shoot length (20.49%), leaf protein (121.53%), root protein (99.93%), shoot protein (33.65%), leaf phenolics (47.90%), root phenolics (25.82%), shoot phenolics (25.85%), leaf chlorophyll a (57.03%), leaf chlorophyll b (23.19%), total chlorophyll (43.77%), leaf malondialdehyde (125.07%), root malondialdehyde (78.03%) and shoot malondialdehyde (131.16%) across various Cd levels compared to the control group. The synergistic effect of GA3 and BC manifested in optimal leaf protein and malondialdehyde levels indicating induced tolerance and mitigation of Cd detrimental impact on plant growth. The enriched soils showed resistance to heavy metal toxicity emphasizing the potential of BC and GA3 as viable strategy for enhancing maize growth. The application of biochar and gibberellic acid emerges as an effective means to mitigate cadmium-induced stress in maize, presenting a promising avenue for sustainable agricultural practices.

Selective Removal of Chlorophyll and Isolation of Lutein from Plant Extracts Using Magnetic Solid Phase Extraction with Iron Oxide Nanoparticles.

In recent years, there has been a growing interest in plant pigments as readily available nutraceuticals. Photosynthetic pigments, specifically chlorophylls and carotenoids, renowned for their non-toxic antioxidant properties, are increasingly finding applications beyond their health-promoting attributes. Consequently, there is an ongoing need for cost-effective methods of isolation. This study employs a co-precipitation method to synthesize magnetic iron oxide nanoparticles. Scanning electron microscopy (SEM) coupled with energy dispersive spectrometry (EDS) confirms that an aqueous environment and oxidizing conditions yield nanosized iron oxide with particle sizes ranging from 80 to 140 nm. X-ray photoelectron spectroscopy (XPS) spectra indicate the presence of hydrous iron oxide FeO(OH) on the surface of the nanosized iron oxide. The Brunauer-Emmett-Teller (BET) surface area of obtained nanomaterial was 151.4 m2 g-1, with total pore volumes of pores 0.25 cm3 g-1 STP. The material, designated as iron oxide nanoparticles (IONPs), serves as an adsorbent for magnetic solid phase extraction (MSPE) and isolation of photosynthetic pigments (chlorophyll a, lutein) from extracts of higher green plants (Mentha piperita L., Urtica dioica L.). Sorption of chlorophyll a onto the nanoparticles is confirmed using UV-vis spectroscopy, Fourier transform infrared photoacoustic spectroscopy (FT-IR/PAS), and high-performance liquid chromatography (HPLC). Selective sorption of chlorophyll a requires a minimum of 3 g of IONPs per 12 mg of chlorophyll a, with acetone as the solvent, and is dependent on a storage time of 48 h. Extended contact time of IONPs with the acetone extract, i.e., 72 h, ensures the elimination of remaining components except lutein, with a spectral purity of 98%, recovered with over 90% efficiency. The mechanism of chlorophyll removal using IONPs relies on the interaction of the pigment's carbonyl (C=O) groups with the adsorbent surface hydroxyl (-OH) groups. Based on molecular dynamics (MD) simulations, it has been proven that the selective adsorption of pigments is also influenced by more favorable dispersion interactions between acetone and chlorophyll in comparison with other solutes. An aqueous environment significantly promotes the removal of pigments; however, it results in a complete loss of selectivity.

Integrated ultrastructural, physiological, transcriptomic, and metabolomic analysis uncovers the mechanisms by which nicotinamide alleviates cadmium toxicity in Pistia stratiotes L.

Exogenous nicotinamide (NIC) is a promising solution to relieve heavy metal (HM) toxicity in plants. Nonetheless, the underlying mechanisms involved remain poorly understood. As NIC addition (200 µM) can increase the tolerance of Pistia stratiotes L. to Cd stress (10 mg L-1), this strategy was subjected to integrated ultrastructural, physiological, transcriptomic, and metabolomic analysis to reveal the mechanisms involved. Exogenous NIC initiated a series of physiological, transcriptional, and metabolic responses that alleviated Cd damage. NIC addition improved Cd transfer from roots to leaves and reduced Cd damage in roots. The transported Cd to leaves did not induce further toxicity because it was abundantly compartmentalised in cell walls, which might be mediated by lignin synthesis. Moreover, NIC addition improved the repair of photosystem II in leaves under Cd stress by inducing key genes (e.g., chlorophyll A-B binding protein and PSII repair protein encoding genes), resulting in the restoration of Fv/Fm. In addition, antioxidant enzyme activities (e.g., peroxidase and catalase) and synthesis of antioxidants (e.g., stachydrine and curculigoside) were triggered to overcome oxidative stress. Our work paves the way for a deeper understanding of the mechanisms by which NIC alleviates HM toxicity in plants, providing a basis for improving phytoremediation.

Overexpression of the NbZFP1 encoding a C3HC4-type zinc finger protein enhances antiviral activity of Nicotiana benthamiana.

Viral diseases are crucial determinants affecting tobacco cultivation, leading to a substantial annual decrease in production. Previous studies have demonstrated the regulatory function of the C3HC4 family of plant zinc finger proteins in combating bacterial diseases. However, it remains to be clarified whether this protein family also plays a role in regulating resistance against plant viruses. In this study, the successful cloning of the zinc finger protein coding gene NbZFP1 from Nicotiana benthamiana has been achieved. The full-length coding sequence of NbZFP1 is 576 bp. Further examination and analysis of this gene revealed its functional properties. The induction of NbZFP1 transcription in N. benthamiana has been observed in response to TMV, CMV, and PVY. Transgenic N. benthamiana plants over-expressing NbZFP1 demonstrated a notable augmentation in the production of chlorophyll a (P < 0.05). Moreover, NbZFP1-overexpressing tobacco exhibited significant resistance to TMV, CMV, and PVY, as evidenced by a decrease in virus copies (P < 0.05). In addition, the defense enzymes activities of PAL, POD, and CAT experienced a significant increase (P < 0.05). The up-regulated expression of genes of NbPAL, NbNPR1 and NbPR-1a, which play a crucial role in SA mediated defense, indicated that the NbZFP1 holds promise in enhancing the virus resistance of tobacco plant. Importantly, the results demonstrate that NbZFP1 can be considered as a viable candidate gene for the cultivation of crops with enhanced virus resistance.

Physiological responses of low- and high-cadmium accumulating Robinia pseudoacacia-rhizobium symbioses to cadmium stress.

The role of rhizobia in alleviating cadmium (Cd) stress in woody legumes is still unclear. Therefore, two types of black locust (Robinia pseudoacacia L.) with high and low Cd accumulation abilities were selected from 11 genotypes in China, and the effects of rhizobium (Mesorhizobium huakuii GP1T11) inoculation on the growth, CO2 and H2O gas exchange parameters, Cd accumulation, and the absorption of mineral elements of the high (SX) and low Cd-accumulator (HB) were compared. The results showed that rhizobium-inoculation significantly increased biomass, shoot Cd contents, Cd accumulation, root-to-shoot translocation factor (TF) and the absorption and accumulation of mineral elements in both SX and HB. Rhizobium-inoculation increased chlorophyll a and carotenoid contents, and the intercellular carbon dioxide concentrations in HB plants. Under Cd exposure, the high-accumulator SX exhibited a significant decrease in photosynthetic CO2 fixation (Pn) and an enhanced accumulation of Cd in leaves, but coped with Cd exposure by increasing chlorophyll synthesis, regulating stomatal aperture (Gs), controlling transpiration (Tr), and increasing the absorption and accumulation of mineral elements. In contrast, the low-accumulator HB was more sensitive to Cd exposure despite preferential accumulation of Cd in roots, with decreased chlorophyll and carotenoid contents, but significantly increased root biomass. Compared to the low-accumulator HB, non-inoculated Cd-exposed SX plants had higher chlorophyll contents, and rhizobium-inoculated Cd-exposed SX plants had higher Pn, Tr, and Gs as well as higher levels of P, K, Fe, Ca, Zn, and Cu. In conclusion, the high- and low-Cd-accumulator exhibited different physiological responses to Cd exposure. Overall, rhizobium-inoculation of black locust promoted the growth and heavy metal absorption, providing an effective strategy for the phytoremediation of heavy metal-contaminated soils by this woody legume.

The Effect of Ethephon on Ethylene and Chlorophyll in Zoysia japonica Leaves.

Zoysia japonica (Zoysia japonica Steud.) is a kind of warm-season turfgrass with many excellent characteristics. However, the shorter green period and longer dormancy caused by cold stress in late autumn and winter are the most limiting factors affecting its application. A previous transcriptome analysis revealed that ethephon regulated genes in chlorophyll metabolism in Zoysia japonica under cold stress. Further experimental data are necessary to understand the effect and underlying mechanism of ethephon in regulating the cold tolerance of Zoysia japonica. The aim of this study was to evaluate the effects of ethephon by measuring the enzyme activity, intermediates content, and gene expression related to ethylene biosynthesis, signaling, and chlorophyll metabolism. In addition, the ethylene production rate, chlorophyll content, and chlorophyll a/b ratio were analyzed. The results showed that ethephon application in a proper concentration inhibited endogenous ethylene biosynthesis, but eventually promoted the ethylene production rate due to its ethylene-releasing nature. Ethephon could promote chlorophyll content and improve plant growth in Zoysia japonica under cold-stressed conditions. In conclusion, ethephon plays a positive role in releasing ethylene and maintaining the chlorophyll content in Zoysia japonica both under non-stressed and cold-stressed conditions.

Photosensitizing effects and physicochemical properties of chlorophyll a derivatives with hydrophilic oligoethylene glycol fragments at the macrocycle periphery.

In this work, screening studies of the cytotoxic effect of chlorins with fragments of di-, tri-, and pentaethylene glycol at the macrocycle periphery in relation to HeLa, A549, and HT29 cells were performed. It is shown that, despite different hydrophobicity, all the compounds studied have a comparable photodynamic effect. The conjugate of chlorin e6 with pentaethylene glycol, which has the lowest tendency to association among the studied compounds with tropism for low density lipoproteins and the best characteristics of the formation of molecular complexes with Tween 80, has a significant difference in dark and photoinduced toxicity (ratio IC50(dark)/IC50(photo) approximately 2 orders of magnitude for all cell lines), which allows to hope for a sufficiently large "therapeutic window". A study of the interaction of this compound with HeLa cells shows that the substance penetrates the cell and, after red light irradiation induces ROS appearance inside the cell, associated, apparently, with the photogeneration of singlet oxygen. These data indicate that photoinduced toxic effects are caused by damage to intracellular structures as a result of oxidative stress. Programmed type of cell death characterized with caspase-3 induction is prevailing. So, the conjugate of chlorin e6 with pentaethylene glycol is a promising antitumor PS that can be successfully solubilized with Tween 80, which makes it suitable for further in vivo studies.

Concurrent enhancement of biomass production and phycocyanin content in salt-stressed Arthrospira platensis: A glycine betaine- supplementation approach.

In industrial-scale cultivation of microalgae, salinity stress often stimulates high-value metabolites production but decreases biomass yield. In this research, we present an extraordinary response of Arthrospira platensis to salinity stress. Specifically, we observed a significant increase in both biomass production (2.58 g L-1) and phycocyanin (PC) content (22.31%), which were enhanced by 1.26-fold and 2.62-fold, respectively, compared to the control, upon exposure to exogenous glycine betaine (GB). The biochemical analysis reveals a significant enhancement in carbonic anhydrase activity and chlorophyll a level, concurrent with reductions in carbohydrate content and reactive oxygen species (ROS) levels. Further, transcriptomic profiling indicates a downregulation of genes associated with the tricarboxylic acid (TCA) cycle and an upregulation of genes linked to nitrogen assimilation, hinting at a rebalanced carbon/nitrogen metabolism favoring PC accumulation. This work thus presents a promising strategy for simultaneous enhancement of biomass production and PC content in A. platensis and expands our understanding of PC biosynthesis and salinity stress responses in A. platensis.

Integrated approaches for heavy metal-contaminated soil remediation: harnessing the potential of Paulownia elongata S. Y. Hu, Oscillatoria sp., arbuscular mycorrhizal fungi (Glomus mosseae and Glomus intraradices), and iron nanoparticles.

In recent years, researchers have extensively investigated the remediation of heavy metal-contaminated soil using plants, microorganisms, and iron nanoparticles. The objective of this study was to investigate and compare the individual and simultaneous effects of Paulownia elongata S. Y. Hu, cyanobacteria (Oscillatoria sp.), arbuscular mycorrhizal fungi (AMF) including Glomus mosseae and Glomus intraradices, and zero-valent iron nanoparticles (nZVI) on the remediation of heavy metal-contaminated soil containing chromium (Cr VI and Cr III) and nickel (Ni). The study found significant variations in parameters such as pH (acidity), electrical conductivity (EC), nitrogen (N), phosphorus (P), potassium (K), and organic carbon (OC) among different treatments. The addition of cyanobacteria, AMF, and nZVI influenced these properties, resulting in both increases and decreases compared to the control treatment. The treatment involving a combination of cyanobacteria, AMF, and nZVI (CCAN25) exhibited the highest increase in growth parameters, such as total dry mass, root length, stem diameter, and leaf area, while other treatments showed varied effects on plant growth. Moreover, the CCAN25 treatment demonstrated the highest increase in chlorophyll a, chlorophyll b, and carotenoid levels, whereas other treatments displayed reductions in these pigments compared to the control. Moderate phytoaccumulation of Cr and Ni in P. elongata samples across all treatments was observed, as indicated by the bioconcentration factor and bioaccumulation coefficient values being less than 1.0 for both metals. The findings provide insights into the potential application of these treatments for soil remediation and plant growth enhancement in contaminated environments.

Phosphorus limitation combined with aluminum triggers synergistic responses on the freshwater microalgae Raphidocelis subcapitata (Chlorophyceae).

In the environment, algae are exposed to several stressors such as limitation of essential nutrients and excess of toxic substances. It is well known the importance of phosphorus (P) supply for healthy metabolism of algae and impacts at this level can affect the whole aquatic trophic chain. Aluminum (Al) is the most abundant metal on Earth and it is toxic to different trophic levels. Processes related to P and Al assimilation still need to be clarified and little is known about the responses of microalgae exposed to the two stressors simultaneously. We evaluated the effects of environmental concentrations of Al and P limitation, isolated and in combination, on growth, pigment production and photosynthesis of the freshwater microalga Raphidocelis subcapitata. Both stressors affected cell density, chlorophyll a, carotenoids, and maximum quantum yield. Al did not affect any other evaluated parameter, while P limitation affected parameters related to the dissipation of heat by algae and the maximum electron transport rate, decreasing the saturation irradiance. In the combination of both stressors, all parameters evaluated were affected in a synergistic way, i.e., the results were more harmful than expected considering the responses to isolated stressors. Our results indicate that photoprotection mechanisms of algae were efficient in the presence of both stressors, avoiding damages to the photosynthetic apparatus. In addition, our data highlight the higher susceptibility of R. subcapitata to Al in P-limited conditions.

Nitric oxide reduces cadmium uptake in wheat (Triticum aestivum L.) by modulating growth, mineral uptake, yield attributes, and antioxidant profile.

Wheat (Triticum aestivum L.) is among the plants that are at risk from cadmium (Cd), a hazardous heavy metal that can be fatal due to its rapid absorption and high mobility. Being taken up from the soil and moving to the shoots and roots of edible plants, it enters the food chain and poses a health concern to people worldwide. A strategically important cereal crop, wheat has a demonstrated role in human health systems, particularly in poor nations. In this study, we describe the effects of nitric oxide (NO) on the growth, nutrition, and physiological functions of commercially cultivated wheat cvs. Galaxy 2013 and Akbar 2019 under Cd stress. Four-week-old plants were subjected to Cd (0.5 mM) stress, and after 2 weeks of Cd toxicity, foliar application of nitric oxide (100 and 150 µM) was carried out. As evident from excessive antioxidant production, Cd toxicity increased reactive oxygen species (ROS) level like H2O2 and significantly (p ≤ 0.001) decreased nutrient acquisition, growth, and yield attributes of plants under experiment. The severity of the effect varied between cultivars under investigation. A minimum accumulation of MDA (44%) and H2O2 (55%) was found in the cv. Akbar 2019 under Cd stress, whilst cv. Galaxy 2013 showed the highest accumulation of the oxidative stress indicators malondialdehyde content (MDA) (48%) and H2O2 (60%). Reduced and oxidized glutathione contents were also increased under Cd-induced toxicity. The application of NO resulted in a significant improvement of 22, 25, 25, and 30% in shoot fresh weight, root fresh weight, shoot dry weight, and root dry weight, respectively. Additionally, there was an increased uptake of Ca+2 (16%), K+1 (5%), chlorophyll a (46%), b (32%), a/b ratio (41%), and carotenoid (28%). When compared with Cd-stressed plants, yield parameters like 100 grain weight, number of tillers plant-1, and grain yield plant-1 improved by 14, 17, and 33%, respectively, under NO application. We concluded from the results of this study that NO treatments increased plant development by lowering oxidative stress and limiting Cd uptake. It is inferred from the results of this study that wheat production with reduced heavy metal uptake may be facilitated using NO due to its cytoprotective properties and its interaction with ROS.