Editorial: Micronutrients: The Borderline Between Their Beneficial Role and Toxicity in Plants

An assessment of metal concentrations in leaves, roots, and associated sediments of mangrove plant (Avicennia marina) in the Myeik area, Myanmar

The Myeik region in Myanmar hosts extensive mangrove forests, however, increasing human activities like mining and agriculture have caused heavy metal pollution. This study investigates the role of Avicennia marina in metal dynamics and contamination status in Myeik through metal concentration analysis in leaves, roots, and sediments. Bioconcentration factors (BCF) and translocation factors (TF) were calculated, and ecological indices were used to assess contamination levels and ecological risks. Sediments had higher metal concentrations than plant parts, with nonessential elements (As, Cd, Co, Cr, Pb) averaging 83.2 ± 21.4, 3.16 ± 0.58, 25.6 ± 4.3, 55.1 ± 14.2, and 87 ± 18 mg/kg, and essential elements (Cu, Fe, Mn, Ni, Zn) averaging 21.0 ± 8.0, 18,283 ± 1614, 719 ± 312, 81 ± 30, and 108 ± 32 mg/kg. A. marina showed high BCF for Cd and Cu, and essential elements (Ni, Zn, Mn) exhibited higher TF than nonessential elements (As, Pb, Co). Ecological indices indicated significant contamination and risks due to As, Cd, and Pb, mainly sourced from mining and industrial activities. The contamination levels are ranked as Inlaymyine > Kyweku > Lighthouse. A. marina's metal uptake and translocation were influenced by local environmental factors and physiological responses. Mangrove sediments retained more metals than mudflats, showing habitat-specific differences. These findings highlight the potential of A. marina as a bioindicator of heavy metal pollution and its significant contribution to natural bioremediation processes in the Myeik.

Brassinosteroids in Micronutrient Homeostasis: Mechanisms and Implications for Plant Nutrition and Stress Resilience

Brassinosteroids (BRs) are crucial plant hormones that play a significant role in regulating various physiological processes, including micronutrient homeostasis. This review delves into the complex roles of BRs in the uptake, distribution, and utilization of essential micronutrients such as iron (Fe), zinc (Zn), manganese (Mn), copper (Cu), and boron (B). BRs influence the expression of key transporter genes responsible for the absorption and internal distribution of these micronutrients. For iron, BRs enhance the expression of genes related to iron reduction and transport, improve root architecture, and strengthen stress tolerance mechanisms. Regarding zinc, BRs regulate the expression of zinc transporters and support root development, thereby optimizing zinc uptake. Manganese homeostasis is managed through the BR-mediated regulation of manganese transporter genes and chlorophyll production, essential for photosynthesis. For copper, BRs influence the expression of copper transporters and maintain copper-dependent enzyme activities crucial for metabolic functions. Finally, BRs contribute to boron homeostasis by regulating its metabolism, which is vital for cell wall integrity and overall plant development. This review synthesizes recent findings on the mechanistic pathways through which BRs affect micronutrient homeostasis and discusses their implications for enhancing plant nutrition and stress resilience. Understanding these interactions offers valuable insights into strategies for improving micronutrient efficiency in crops, which is essential for sustainable agriculture. This comprehensive analysis highlights the significance of BRs in micronutrient management and provides a framework for future research aimed at optimizing nutrient use and boosting plant productivity.

Autecology and determination of relationships between nutrients in soil and sage plant (Salvia eremophila Boiss.) in the south of Yazd province

This study aims to investigate the autecology and determine the relationship between the nutritional elements in the soil and the Sage plant (Salvia eremophila Boiss.) in the south of Yazd province. The main habitats were determined, which contained various ecological characteristics. Total potassium (K), total nitrogen (N), total phosphorus (P), total sugar content (TSC), and proline content of the plants were determined. In addition, macro and microelement contents such as total N, extractable K, extractable magnesium (Mg), available P, available iron (Fe), and available manganese (Mn) of the study areas were determined. The highest concentrations of TSC (72.90 mg kg-1 ± 3.87) and TN (0.265 g kg-1 ± 0.021) of the plant, and also the highest extractable Mg (26.60 mg kg-1 ± 1.70) and available Fe (0.44 mg kg-1 ± 0.19), of soil were related to the Qavam Abad habitat. The highest concentrations of total K (17.495 g kg-1 ± 4.91) and total P (1.206 g kg-1 ± 0.257) of plants, and the highest extractable K (356.68 g kg-1 ± 63.53) of soil belonged to the Tang Chenar Station. The highest TN content (6.3 g kg-1 ± 1.21) of soil and the highest proline content (0.015 g kg-1 ± 0.003) of plants was related to the Damgahan habitat. Also, the concentrations of soil available Mn and available P had the highest levels in the Damgahan (0.60 g kg-1 ± 0.34) and Qavam Abad habitats (0.075 g kg-1 ± 30.74), respectively. There was no significant difference between the amount of nutrients and soil elements in the studied stations (p < 0.05). There was a positive and significant correlation between the amount of soil TN and plant TN (Pvalues = 0.001, R2 = 0.87). An inverse and significant correlation was also observed between the amount of soil available P and plant total P (Pvalues = 0.014, R2 = - 0.72). This study highlights the various environmental controls over soil's physicochemical properties, which have significant implications for the management of soil nutrients.

Iron/Copper/Phosphate nanocomposite as antimicrobial, antisnail, and wheat growth-promoting agent

BACKGROUND

One of the current challenges is to secure wheat crop production to meet the increasing global food demand and to face the increase in its purchasing power. Therefore, the current study aimed to exploit a new synthesized nanocomposite to enhance wheat growth under both normal and drought regime. The effectiveness of this nanocomposite in improving the microbiological quality of irrigation water and inhibiting the snail's growth was also assessed.

RESULTS

Upon the employed one-step synthesis process, a spherical Fe/Cu/P nanocomposite was obtained with a mean particle size of 4.35 ± 1.524 nm. Cu2+, Fe2+, and P4+ were detected in the dried nanocomposite at 14.533 ± 0.176, 5.200 ± 0.208, and 34.167 ± 0.203 mg/ml concentration, respectively. This nanocomposite was found to exert antibacterial activity against Escherichia coli and Salmonella typhi. It caused good inhibition percent against Fusarium oxysporum (43.5 ± 1.47%) and reduced both its germination rate and germination efficiency. The lethal concentration 50 (LC50) of this nanocomposite against Lanistes carinatus snails was 76 ppm. The treated snails showed disturbance in their feeding habit and reached the prevention state. Significant histological changes were observed in snail digestive tract and male and female gonads. Drought stress on wheat's growth was mitigated in response to 100 and 300 ppm treatments. An increase in all assessed growth parameters was reported, mainly in the case of 100 ppm treatment under both standard and drought regimes. Compared to control plants, this stimulative effect was accompanied by a 2.12-fold rise in mitotic index and a 3.2-fold increase in total chromosomal abnormalities.

CONCLUSION

The finding of the current study could be employed to mitigate the effect of drought stress on wheat growth and to enhance the microbiological quality of irrigation water. This is due to the increased efficacy of the newly synthesized Fe/Cu/P nanocomposite against bacteria, fungi, and snails. This methodology exhibits potential for promoting sustainable wheat growth and water resource conservation.

Differential response of nano zinc sulphate with other conventional sources of Zn in mitigating salinity stress in rice grown on saline-sodic soil

Salinization causes the degradation of the soil and threatening the global food security but the application of essential micronutrients like zinc (Zn), improve the plant growth by stabilizing the plant cell and root development. Keeping in view the above-mentioned scenario, an experiment was conducted to compare the efficiency of conventional Zn fertilizers like zinc sulphate (ZnSO₄), zinc ethylene diamine tetra acetic acid (Zn-EDTA) and advance nano Zn fertilizers such as zinc sulphate nanoparticles (ZnSO₄NPs), and zinc oxide nanoparticles (ZnONPs) (applied at the rate of 5 and 10 mg/kg) in saline-sodic soil. Results revealed that the maximum plant height (67%), spike length (72%), root length (162%), number of tillers (71%), paddy weight (100%), shoot dry weight (158%), and root dry weight (119%) was found in ZnSO₄NPs applied at the rate of 10 mg/kg (ZnSO₄NPs-10) as compared to salt-affected control (SAC). Similarly, the plants physiological attributes like chlorophyll contents (91%), photosynthesis rate (113%), transpiration rate (106%), stomatal conductance (56%) and internal CO₂ (11%) were increased by the application of ZnSO₄NPs-10, as compared to SAC. The maximum Zn concentration in root (153%), shoot (205%) and paddy (167%) found in ZnSO₄NPs-10, as compared to control. In the body of rice plants, other nutrients like phosphorus and potassium were also increased by the application of ZnSO₄NPs-10 and soil chemical attributes such as sodium and sodium adsorption ratio were decreased. The current experiment concluded that the application of ZnSO₄NPs at the rate of 10 mg/kg in salt-affected paddy soil increased the growth, physiology, up take of essential nutrients and yield of rice by balancing the cationic ratio under salt stress.

The Panoramic View of Ecuadorian Soil Nutrients (Deficit/Toxicity) from Different Climatic Regions and Their Possible Influence on the Metabolism of Important Crops

Soil nutrients influence all stages (reproduction, growth, and development) of a plant species' life, and it is known that the deficit and/or toxicity of one or more nutrients has negative effects on the production of crops of commercial interest. Ecuador represents one of the "mega-diverse" countries in the world, with an agricultural sector of great importance, due to its contribution to the country's economy. This review provides a panoramic view of soil nutrients from different climatic regions of Ecuador and revises the importance of knowledge about the possible influence of nutrients from the soil on the plant metabolism able to influence the crop resistance against pathogens or to enrich the biological characteristics of these crops.

Phyto-Friendly Soil Bacteria and Fungi Provide Beneficial Outcomes in the Host Plant by Differently Modulating Its Responses through (In)Direct Mechanisms

Sustainable agricultural systems based on the application of phyto-friendly bacteria and fungi are increasingly needed to preserve soil fertility and microbial biodiversity, as well as to reduce the use of chemical fertilizers and pesticides. Although there is considerable attention on the potential applications of microbial consortia as biofertilizers and biocontrol agents for crop management, knowledge on the molecular responses modulated in host plants because of these beneficial associations is still incomplete. This review provides an up-to-date overview of the different mechanisms of action triggered by plant-growth-promoting microorganisms (PGPMs) to promote host-plant growth and improve its defense system. In addition, we combined available gene-expression profiling data from tomato roots sampled in the early stages of interaction with Pseudomonas or Trichoderma strains to develop an integrated model that describes the common processes activated by both PGPMs and highlights the host's different responses to the two microorganisms. All the information gathered will help define new strategies for the selection of crop varieties with a better ability to benefit from the elicitation of microbial inoculants.

Rhizofiltration of combined arsenic-fluoride or lead-fluoride polluted water using common aquatic plants and use of the 'clean' water for alleviating combined xenobiotic toxicity in a sensitive rice variety

Groundwater co-contamination with toxic pollutants like arsenic-fluoride or lead-fluoride is a serious threat for safe rice cultivation, since major stretches of land, involved in cultivation of this staple food crop are presently experiencing severe endemic pollution from these xenobiotic combinations. Preliminary investigations established that the combined pollutants together exerted more phytotoxicity in the widely cultivated indica rice variety Khitish, compared with that exerted by the individual contaminants. Thus, an ecologically sustainable and economically viable phytoremediative strategy was designed where three aquatic plants, viz., Azolla (water fern), Pistia (water lettuce) and Eichhornia (water hyacinth) (commonly located across the co-polluted regions) were tested for their ability to rhizofiltrate the water samples that had been polluted with arsenic-fluoride or lead-fluoride. Water lettuce exhibited the highest ability to 'clean' both arsenic-fluoride and lead-fluoride polluted water due to its capacity of efficient phytoextraction and phytostabilization. Irrigation of Khitish seedlings with this de-polluted water appreciably reduced malondialdehyde formation, electrolyte leakage and irreversible protein carbonylation due to suppression in NADPH oxidase activity and reactive oxygen species production, compared with those in sets grown with non-treated, arsenic-fluoride or lead-fluoride contaminated water. Oxidative injuries, cytotoxic methylglyoxal synthesis and inhibition of biomass growth were ameliorated, and chlorophyll synthesis and Hill activity were increased due to reduced bioaccumulation of xenobiotics, along with the improved uptake of vital micronutrients like iron, copper and nickel. Overall, the current investigation illustrated a cheap, farmer-friendly blueprint which could be easily promulgated to ensure safe rice cultivation even across territories that are severely co-polluted with the mixed contaminants.