Synergistic interplay between melatonin and hydrogen sulfide enhances cadmium induced oxidative stress resistance in stock (Matthiola incana L.)

Ornamental crops particularly cut flowers are considered sensitive to heavy metals (HMs) induced oxidative stress condition. Melatonin (MLT) is a versatile phytohormone with the ability to mitigate abiotic stresses induced oxidative stress in plants. Similarly, signaling molecules such as hydrogen sulfide (H2S) have emerged as potential options for resolving HMs related problems in plants. The mechanisms underlying the combined application of MLT and H2S are not yet explored. Therefore, we evaluated the ability of individual and combined applications of MLT (100 μM) and H2S in the form of sodium hydrosulfide (NaHS), a donor of H2S, (1.5 mM) to alleviate cadmium (Cd) stress (50 mg L−1) in stock (Matthiola incana L.) plants by measuring various morpho-physiological and biochemical characteristics. The results depicted that Cd-stress inhibited growth, photosynthesis and induced Cd-associated oxidative stress as depicted by excessive ROS accumulation. Combined application of MLT and H2S efficiently recovered all these attributes. Furthermore, Cd stress-induced oxidative stress markers including electrolyte leakage, malondialdehyde, and hydrogen peroxide are partially reversed in Cd-stressed plants by MLT and H2S application. This might be attributed to MLT or H2S induced antioxidant plant defense activities, which effectively reduce the severity of oxidative stress indicators. Overall, MLT and H2S supplementation, favorably regulated Cd tolerance in stock; yet, the combined use had a greater effect on Cd tolerance than the independent application

Silicon nanoparticles alleviate cadmium toxicity in rice by modulating the nutritional profile and triggering stress-responsive genetic mechanisms

This study investigated the physiological and molecular responses of rice genotype ‘9311’ to Cd stress and the mitigating effects of silicon oxide nanoparticles (SiO NPs). Cd exposure severely hindered plant growth, chlorophyll content, photosynthesis, and Cd accumulation. However, SiO NPs supplementation, particularly the SiONP100 treatment, significantly alleviated Cd-induced toxicity, mitigating the adverse effects on plant growth while maintaining chlorophyll content and photosynthetic attributes. The SiONP100 treatment also reduced Cd accumulation, indicating a preference for Si uptake in genotype 9311. Complex interactions among Cd, Si, Mg, Ca, and K were uncovered, with fluctuations in MDA and H2O2 contents. Distinct morphological changes in stomatal aperture and mesophyll cell structures were observed, including changes in starch granules, grana thylakoids, and osmophilic plastoglobuli. Moreover, following SiONP100 supplementation, genotype 9311 increased peroxidase, superoxide dismutase, and catalase activities by 56%, 44%, and 53% in shoots and 62%, 49%, and 65% in roots, respectively, indicating a robust defense mechanism against Cd stress. Notably, OsNramp5, OsHMA3, OsSOD-Cu/Zn, OsCATA, OsCATB, and OsAPX1 showed significant expression after SiO NPs treatment, suggesting potential Cd translocation within rice tissues. Overall, SiO NPs supplementation holds promise for enhancing Cd tolerance in rice plants while maintaining essential physiological functions

Effectiveness of feeding different biochars on growth, digestibility, body composition, hematology and mineral status of the Nile tilapia, Oreochromis niloticus

Oreochromis niloticus fingerlings (5.15 ± 0.02 g; n = 315) were fed with different types of biochar (BC)-supplemented sunflower meal-based (SFM) diet to investigate the effects of various BC inclusions on their nutritional digestibility, body composition, hematology and mineral status for 60 days. Seven different diets were formulated based on the SFM based diet: one was a control (TD-I, CON) and the other six diets were supplemented with 2% BC derived from different sources. These BCs were derived from the following: cotton stick (CSBC, TD-II), wheat straw (WSBC, TD-III), corn cob (CCBC, TD-IV), house waste (HWBC, TD-V), grass waste (GWBC, TD-VI), and green waste (GwBC, TD-VII) biochar. There were three replicates for each test diet. Each tank had fifteen tilapia fingerlings, and they were fed with 5% of their live wet weight and twice daily. The outcomes showed that the supplementation of CCBC significantly elevated the growth, nutrient absorption, and body composition of the O. niloticus fingerlings (p p O. niloticus

Effect of green-synthesized copper oxide nanoparticles on growth, physiology, nutrient uptake, and cadmium accumulation in Triticum aestivum (L.)

Cadmium (Cd) stress in crops has been serious concern while little is known about the copper oxide nanoparticles (CuO NPs) effects on Cd accumulation by crops. This study investigated the effectiveness of CuO NPs in mitigating Cd contamination in wheat (Triticum aestivum L.) cultivation through a pot experiment, presenting an ecofriendly solution to a critical agricultural concern. The CuO NPs, synthesized using green methods, exhibited a circular shape with a crystalline structure and a particle size ranging from 8 to 12 nm. The foliar spray of CuO NPs was applied in four different concentrations i.e. control, 25, 50, 75, 100 mg/L. The obtained data demonstrated that, in comparison to the control group, CuO NPs had a beneficial influence on various growth metrics and straw and grain yields of T. aestivum. The green CuO NPs improved T. aestivum growth and physiology under Cd stress, enhanced selected enzyme activities, reduced oxidative stress, and decreased malondialdehyde levels in the T. aestivum plants. CuO NPs lowered Cd contents in T. aestivum tissues and boosted the uptake of essential nutrients from the soil. Overall, foliar applied CuO NPs were effective in minimizing Cd contents in grains thereby reducing the health risks associated with Cd excess in humans. However, more in depth studies with several plant species and application methods of CuO NPs are required for better utilization of NPs in agricultural purposes

Alleviating salinity stress in canola (Brassica napus L.) through exogenous application of salicylic acid

Canola, a vital oilseed crop, is grown globally for food and biodiesel. With the enormous demand for growing various crops, the utilization of agriculturally marginal lands is emerging as an attractive alternative, including brackish-saline transitional lands. Salinity is a major abiotic stress limiting growth and productivity of most crops, and causing food insecurity. Salicylic acid (SA), a small-molecule phenolic compound, is an essential plant defense phytohormone that promotes immunity against pathogens. Recently, several studies have reported that SA was able to improve plant resilience to withstand high salinity. For this purpose, a pot experiment was carried out to ameliorate the negative effects of sodium chloride (NaCl) on canola plants through foliar application of SA. Two canola varieties Faisal (V1) and Super (V2) were assessed for their growth performance during exposure to high salinity i.e. 0 mM NaCl (control) and 200 mM NaCl. Three levels of SA (0, 10, and 20 mM) were applied through foliar spray. The experimental design used for this study was completely randomized design (CRD) with three replicates. The salt stress reduced the shoot and root fresh weights up to 50.3% and 47% respectively. In addition, foliar chlorophyll a and b contents decreased up to 61–65%. Meanwhile, SA treatment diminished the negative effects of salinity and enhanced the shoot fresh weight (49.5%), root dry weight (70%), chl. a (36%) and chl. b (67%). Plants treated with SA showed an increased levels of both enzymatic i.e. (superoxide dismutase (27%), peroxidase (16%) and catalase (34%)) and non-enzymatic antioxidants i.e. total soluble protein (20%), total soluble sugar (17%), total phenolic (22%) flavonoids (19%), anthocyanin (23%), and endogenous ascorbic acid (23%). Application of SA also increased the levels of osmolytes i.e. glycine betaine (31%) and total free proline (24%). Salinity increased the concentration of Na+ ions and concomitantly decreased the K+ and Ca2+ absorption in canola plants. Overall, the foliar treatments of SA were quite effective in reducing the negative effects of salinity. By comparing both varieties of canola, it was observed that variety V2 (Super) grew better than variety V1 (Faisal). Interestingly, 20 mM foliar application of SA proved to be effective in ameliorating the negative effects of high salinity in canola plants

Biocontrol potential of lipopeptides produced by the novel Bacillus altitudinis strain TM22A against postharvest Alternaria rot of tomato

Bacillus genus exhibits antagonistic potential against a broad range of pathogenic fungi. This study presents the antifungal potential of lipopeptides (LPs) produced by a novel strain Bacillus altitudinis TM22A to suppress the infection of Alternaria rot on tomato. We investigated the antifungal effect of ten Bacillus species against Alternaria alternata, where four Bacillus strains TM22A, MCM61, S2, and CPCF54 exhibited antifungal activity. The LPs extracted from TM22A, MCM61, S2, and CPCF54 restricted mycelial growth and conidial germination of A. alternata in vitro with the highest inhibition produced by TM22A. Liquid chromatography and mass spectrometry (LC-MS) analysis revealed the presence of surfactin, fengycin, iturin, bacillibactin, and bacilysin in strain TM22A at 1036.69, 1435.76, 1085.58, 883.26, and 271.13 m/z respectively. In an In planta assay LPs from TM22A caused the lowest lesion diameter and disease incidence on tomato fruit. Furthermore, the defense enzymes viz, catalase (CAT), polyphenol oxidase (PPO), peroxidase (POD), superoxide dismutase (SOD), and phenylalanine ammonia-lyase (PAL) were enhanced in Bacillus LPs treated tomato fruit with the more pronounced impact in response to TM22A. Post-harvest quality analysis revealed little impact on ascorbic acid, fruit pH, total soluble solids (TSS), titratable acidity (TA), weight loss, and fruit firmness compared to healthy control. This is the first comprehensive study to reveal the antifungal effect of Bacillus-derived LPs against postharvest Alternaria rot of tomato and its role in defense elicitation to protect the fruit from pathogen invasion

Cobalt and Titanium Alleviate the Methylglyoxal-Induced Oxidative Stress in Pennisetum divisum Seedlings under Saline Conditions

Salinity is considered to be a global problem and a severe danger to modern agriculture since it negatively impacts plants’ growth and development at both cellular- and whole-plant level. However, cobalt (Co) and titanium (Ti), multifunctional non-essential micro-elements, play a crucial role in improving plant growth and development under salinity stress. In the current study, Co and Ti impact on the morphological, biochemical, nutritional, and metabolic profile of Pennisetum divisum plants under three salinity levels which were assessed. Two concentrations of Co (Co-1; 15.0 mg/L and Co-2; 25.0 mg/L), and two concentrations of Ti (Ti-1; 50.0 mg/L and Ti-2; 100.0 mg/L) were applied as foliar application to the P. divisum plants under salinity (S1; 200 mM, S2; 500 mM, and S3; 1000 mM) stress. The results revealed that various morphological, biochemical, and metabolic processes were drastically impacted by the salinity-induced methylglyoxal (MG) stress. The excessive accumulation of salt ions, including Na+ (1.24- and 1.21-fold), and Cl− (1.53- and 1.15-fold) in leaves and roots of P. divisum, resulted in the higher production of MG (2.77- and 2.95-fold) in leaves and roots under severe (1000 mM) salinity stress, respectively. However, Ti-treated leaves showed a significant reduction in ionic imbalance and MG concentrations, whereas considerable improvement was shown in K+ and Ca2+ under salinity stress, and Co treatment showed downregulation of MG content (26, 16, and 14%) and improved the antioxidant activity, such as a reduction in glutathione (GSH), oxidized glutathione (GSSG), Glutathione reductase (GR), Glyoxalase I (Gly I), and Glyoxalase II (Gly II) by up to 1.13-, 1.35-, 3.75-, 2.08-, and 1.68-fold under severe salinity stress in P. divisum roots. Furthermore, MG-induced stress negatively impacted the metabolic profile and antioxidants activity of P. divisum’s root and leaves; however, Co and Ti treatment considerably improved the biochemical processes and metabolic profile in both underground and aerial parts of the studied plants. Collectively, the results depicted that Co treatment showed significant results in roots and Ti treatment presented considerable changes in leaves of P. divism under salinity stress

Synthesis and optimizations of nanoparticles from Phragmites karka improves tomato growth and salinity resilience

Halophytes contain many secondary metabolites that can facilitate the capping and stabilizing of nanoparticles. Synthesis and optimization of zinc oxide nanoparticles from Phragmites karka were performed for the first time in this study to assess the salinity resilience of tomato seedlings in 100 mM NaCl using biotechnological applications and growth analysis. Response surface methodology and central composite design data revealed that ZnO NPs were stable at a 2:1 ratio of plant and salt concentration (pH of 6.5 at 37.5 °C). The peak obtained at 331 nm from UV–Vis spectroscopy confirmed the synthesis of ZnO NPs and these NPs have multiple functional groups. The chemical bond formation of the prepared ZnO NPs (assessed using FTIR and XRD) confirmed the crystalline structure of ZnO NPs that were derived from halophyte P. karka. The SEM images revealed that ZnO NPs have a particle size of 23.5 nm and are spherical, while DLS revealed the size (32.6 nm) and zeta-potential (−6.43 mV) of nanoparticles. Plants treated with ZnO NPs increase the overall tomato growth parameters under salt stress, including shoot length (3-fold), especially at T20 (50 mgL −1 ZnO NPs + 100 mM NaCl) treatment among all growth weeks. The number of leaves increased at T16 (20 mgL −1 ZnO NPs + 100 mM NaCl). The numbers of nodes and internodes were increased at T20 (50 mgL −1 ZnO NPs + 100 mM NaCl) in both parameters. Halophytic nanoparticles could be beneficial sources of biostimulants to improve salt resilience of tomato plants undergoing salt stress

Utilization of microalgal-bacterial energy nexus improves CO2 sequestration and remediation of wastewater pollutants for beneficial environmental services

Carbon dioxide (CO2) emissions from the combustion of fossil fuels and coal are primary contributors of greenhouse gases leading to global climate change and warming. The toxicity of heavy metals and metalloids in the environment threatens ecological functionality, diversity and global human life. The ability of microalgae to thrive in harsh environments such as industrial wastewater, polluted lakes, and contaminated seawaters presents new, environmentally friendly, and less expensive CO2 remediation solutions. Numerous microalgal species grown in wastewater for industrial purposes may absorb and convert nitrogen, phosphorus, and organic matter into proteins, oil, and carbohydrates. In any multi-faceted micro-ecological system, the role of bacteria and their interactions with microalgae can be harnessed appropriately to enhance microalgae performance in either wastewater treatment or algal production systems. This algal-bacterial energy nexus review focuses on examining the processes used in the capture, storage, and biological fixation of CO2 by various microalgal species, as well as the optimized production of microalgae in open and closed cultivation systems. Microalgal production depends on different biotic and abiotic variables to ultimately deliver a high yield of microalgal biomass