Search

Coastal areas are facing increasing heavy metal contamination from various human activities, posing a severe threat to aquatic and coastal biodiversity. Mangroves, abundant in coastal and marine ecosystems, are particularly vulnerable to the accumulation of toxic inorganic pollutants and heavy metals (HMs). Mangroves have proved to be effective in mitigating heavy metal pollution through a range of mechanisms, including avoidance, chelation, sequestration, tolerance, excretion, and filtration. Studies highlighted a higher metal bioconcentration of metals in mangrove roots compared to leaves, indicating their remarkable endurance capability towards high levels of HMs. The uptake of HMs by mangrove roots occurs through passive diffusion across cell plasma membranes or active transport, regulated by metal ion transporters and influenced by electrochemical and/or concentration potential gradients. In phytoremediation strategies, mangrove plants employ several physiochemical mechanisms to avoid HMs uptake, such as cell wall immobilization, complexation with biomolecules like phytochelatins (PCs), and extracellular barriers at the root endodermis. Moreover, mangroves can develop iron-plaques on their root surface, acting as reservoirs for immobilized HMs and significantly influencing their sequestration, particularly in wastewater containing Cr, Pb, and Ni ions. Mangroves would also trigger antioxidant defenses to cope with the absorbed HMs and normalize the excessive production of reactive oxygen species (ROS)-mediated oxidative stress. However, the antioxidant response in mangroves varies depending on the concentration and type of toxic HMs, plant species, and exposure duration. Additionally, mangroves excrete excessive amounts of HMs through salt glands via adaxial trichomes, allowing them to mitigate phytotoxicity. Although mangroves demonstrate a high tolerance capacity towards HMs, hydrological alteration, deforestation, marine construction, and marine anthropogenic activities pose significant threats to several global mangrove species. In conclusion, conducting multiple toxicity tests using early mangrove seedlings are imperative that threshold effect concentrations of various HMs be determined under natural environmental conditions encompassing nutrients, salinity, temperature, and the presence of several contaminants. Besides, long-term, large-scale mesocosm experiments in real-field settings should be conducted in future to obtain more realistic and reliable insights into the uptake and tolerance of HMs in mangroves. [Display omitted] • Coastal ecosystem is endangered due to heavy metal contamination due to anthropogenic activities. • Mangroves ecosystem faced adverse effects of HMs toxicities. • Mangroves species mitigate HMs toxicities dependent on HMs type and concentration. • Mangroves tolerate HMs toxicity through cell wall immobilization, complexation with biomolecules and extracellular barriers. • Mangroves Phytoremediate HMs phytotoxicity through salt glands via adaxial trichomes. [ABSTRACT FROM AUTHOR]

Due to higher atmospheric greenhouse gasses concentrations, global warming is undoubtedly the most critical environmental issue that needs an immediate solution. Agroforestry has attained worldwide recognition to cope with this global problem due to its greater potential to sequester atmospheric carbon dioxide along with other ecosystem services, including food security. However, quantitative information about the biomass and carbon sequestration in poplar-maize agroforestry systems is not available in semi-arid climatic zones in Pakistan. The current study was carried out to evaluate the vegetation biomass and carbon stocks under three poplar-maize agroforestry planting patterns under semi-arid climatic conditions in a subdivision Jaranwala, District Faisalabad, Pakistan. The data was collected in three agroforestry patterns like; A (192 trees ha−1), B (255 trees ha−1), and C (296 trees ha−1). Allometric equations were used to estimate the biomass and carbon stock in plant species. Results showed that the poplar tree carbon stock among three planting patterns was significantly different, with maximum carbon stock of 35.62 t ha−1 in pattern C, and it was 8% and 33.5% greater than the carbon stock of pattern B and pattern A, respectively. The maximum aboveground biomass assimilated by maize crop was (11.95 t ha−1) in pattern B, and it was 10.3% and 3.6% greater than pattern A and pattern C, respectively. The grain yield was highest in pattern A as compared to the other two patterns. Additionally, the maximum soil carbon stock in soil was estimated (22.72 t ha-1) in pattern C, at 0-15 cm depth, while it was 13.42% and 6.61% greater than pattern A and pattern B, respectively. In conclusion, the findings of this study suggested that pattern C with maximum biomass production and carbon stocks is the optimum poplar maize planting pattern in requisites of both financial and environmental benefits in the form of carbon sequestration. [ABSTRACT FROM AUTHOR]

Numerous abiotic stressors including heavy metal stresses, specifically cadmium (Cd) stress in agricultural bio-system hinder the plant adequate growth. The present study was aimed to reveal the protective role of silicon (Si) application with two levels and to recognize the optimum level of Si for wheat plants grown hydroponically under three different levels of Cd toxicities. In methodology, we used nine treatments with three levels of Si (0, 1, and 3 mmol L−1; Na 2 SiO 3) against three levels of Cd (0, 50, 200 μmol L−1; CdCl 2) with three biological replicates. The results of our study demonstrated that Si incorporation with the advantage of 3 mmol L−1 in cultured media with Cd50 and Cd200 demolished the toxic effects of Cd on the leaves of wheat plants by increasing plant dry biomass by 88% and 262%, leaf area by 48% and 57%, total chlorophyll contents by 120% and 74%, catalase (CAT) activity by 92% and 110%, superoxide dismutase (SOD) activity by 62% and 78%, peroxidase (POD) activity by 66% and 40%, ascorbic acid (AsA) contents by 33% and 34%, glutathione (GHS) contents by 39% and 30% and reduced MDA contents by 56% and 50%, H 2 O 2 contents by 61% and 66%, and EL contents by 56% and 47% as parallel to Cd corresponding levels. In addition, Si incorporation with the advantage of 3 mmol L−1 significantly increased relative water contents (RWC) to maintain the cell turgor pressure and protect the plant from wilting and cells flaccid and enhanced membrane stability index (MSI) to protect the plant from logging under damaging effects of Cd toxicities. Based on the present findings, Si can be considered a quasi-essential element that enhanced wheat tolerance against Cd toxicity by limiting uptake, accumulation, and translocation of Cd and through regulating antioxidative defense mechanisms. • The Cd accumulation in the leaves of wheat was enhanced under Cd stress alone. • Silicon supply alleviated Cd-induced phytotoxicity in wheat leaves. • Silicon application significantly reduced Cd translocation and thereby its uptake. • Silicon application enhanced nutrients uptake including Si and regulated defense mechanism. • The Si3 (3 mmol L−1) was more effective than Si1 (1 mmol L−1) under all Cd levels. [ABSTRACT FROM AUTHOR]

Anthropogenic activities such as mining, manufacturing, and application of fertilizers release substantial quantities of cadmium (Cd) into the environment. In the natural environment, varying pH may play an important role in the absorption and accumulation of Cd in plants, which can cause toxicity and increase the risk to humans. We conducted a hydroponic experiment to examine the impact of pH on cadmium (Cd) solubility and bioavailability in winter wheat (Triticum aestivum L.) under controlled environmental conditions. The results showed that Cd concentration was significantly reduced in wheat with an increase in pH from 5 to 7, while it was dramatically increased at pH ranging from 7 to 9. However, in both cases, a significant reduction in physiological traits was observed. The addition of Cd (20, 50, and 200 μmol L-1) at all pH levels caused a substantial decline in wheat growth, chlorophyll and carotenoids contents, nutrient availability, while elevated cell membrane damage was observed in terms of electrolytic leakage (EL), osmoprotectants, and antioxidants activity. In our findings, the negative effects of acidic pH (5) on wheat growth and development were more pronounced in the presence of Cd toxicities. For instance, Cd concentration with 20, 50, and 200 μmol L-1 at acidic pH (5) reduced shoot dry biomass by 45%, 53%, and 79%, total chlorophyll contents by 26%, 41%, 56% while increased CAT activity in shoot by 109%, 175%, and 221%, SOD activity in shoot by 122%, 135%, and 167%, POD activity in shoot by 137%, 250%, and 265%, MDA contents in shoot by 51%, 83%, and 150%, H2O2 contents in shoot by 175%, 219%, and 292%, EL in shoot by 108%, 165%, and 230%, proline contents in shoot by 235%, 280%, and 393%, respectively as compared to neutral pH without Cd toxicities. On the other hand, neutral pH with Cd toxicities alleviated the negative effects of Cd toxicity on wheat plants by limiting Cd uptake, reduced reactive oxygen species (ROS) formation, and increased nutrient availability. In conclusion, neutral pH minimized the adverse effects of Cd stress by minimizing its uptake and accumulation in wheat plants. [ABSTRACT FROM AUTHOR]

Silicon (Si), as a quasi-essential element, has a vital role in alleviating the damaging effects of various environmental stresses on plants. Cadmium (Cd) stress is severe abiotic stress, especially in acidic ecological conditions, and Si can demolish the toxicity induced by Cd as well as acidic pH on plants. Based on these hypotheses, we demonstrated 2-repeated experiments to unfold the effects of Si as silica gel on the root morphology and physiology of wheat seedling under Cd as well as acidic stresses. For this purpose, we used nine treatments with three levels of Si nanoparticles (0, 1, and 3 mmol L−1) derived from sodium silicate (Na2SiO3) against three concentrations of Cd (0, 50, and 200 µmol L−1) in the form of cadmium chloride (CdCl2) with three replications were arranged in a complete randomized design. The pH of the nutrient solution was adjusted at 5. The averages of three random replications showed that the mutual impacts of Si and Cd in acidic pH on wheat roots depend on the concentrations of Si and Cd. The collective or particular influence of low or high levels of Si (1 or 3 mM) and acidic pH (5) improved the development of wheat roots, and the collective influence was more significant than that of a single parallel treatment. The combined effects of low or high concentrations of Cd (50 or 200 µM) and acidic pH significantly reduced root growth and biomass while increased antioxidants, and reactive oxygen species (ROS) contents. The incorporation of Si (1 or 3 mmol L−1) in Cd-contaminated acidic nutrient solution promoted the wheat root growth, decreased ROS contents, and further increased the antioxidants in the wheat roots compared with Cd single treatments in acidic pH. The demolishing effects were better with a high level of Si (3 mM) than the low level of Si (1 Mm). In conclusion, we could suggest Si as an effective beneficial nutrient that could participate actively in several morphological and physiological activities of roots in wheat plants grown under Cd and acidic pH stresses. [ABSTRACT FROM AUTHOR]

[Display omitted] • Uptake and translocation of heavy metals exert a range of toxic effects in plants. • Heavy metals cause a range of physiological and biochemical alterations in plants. • Phytohormones can effectively improve plants' resistance to heavy metal stress. • Phytohormones regulate heavy metal toxicity by up-regulating stress-responsive genes. • Phytohormonal cross-talk is also important in the alleviation of heavy metal toxicity. Heavy metal (HM)-mediated toxic effects on plants have attained considerable attention worldwide as they directly threaten the food supply chain. Although various measures have been taken to mitigate the adverse effects of heavy metal stress in plants, significant research gaps must be proactively addressed. Fascinatingly, the exogenous application of phytohormones has recently attained substantial interest in regulating the negative effects of HM stress. Phytohormones are signaling transductional molecules that mitigate HM toxicity in plants and support their growth and development. Both exogenous treatments and manipulation of the endogenous status of phytohormones through regulating their signaling/biosynthesis-related genes are effective strategies for protecting plants against HM-induced toxic effects. However, to achieve maximum benefits from phytohormone-mediated subcellular mechanisms to mitigate HM toxicity, it is necessary to gain in-depth understanding on their potential pathways. The current review focuses primarily on the major mechanistic phytohormonal-mediated approaches involved in alleviating the toxic effects of HMs in plants. Moreover, the potential roles of major phytohormones in triggering protein molecules, signaling transductions, and gene expressions to avoid, tolerate, or alleviate HM toxicity in plants are also discussed. This information provides systematic understanding on the mechanisms of phytohormones in modulating heavy metal tolerance in plants and could help to guide the development of strategies to improve plant tolerance against HM toxicity. [ABSTRACT FROM AUTHOR]

Nanotechnology offers many potential solutions for sustainable agroecosystem, including improvement in nutrient use efficiency, efficacy of pest management, and minimizing the adverse environmental effects of agricultural production. Herein, we first highlighted the integrated application of nanotechnology and precision agriculture for sustainable productivity. Application of nanoparticle mediated material and advanced biosensors in precision agriculture is only possible by nanochips or nanosensors. Nanosensors offers the measurement of various stresses, soil quality parameters and detection of heavy metals along with the enhanced data collection, enabling precise decision-making and resource management in agricultural systems. Nanoencapsulation of conventional chemical fertilizers (known as nanofertilizers), and pesticides (known as nanopesticides) helps in sustained and slow release of chemicals to soils and results in precise dosage to plants. Further, nano-based disease detection kits are popular tools for early and speedy detection of viral diseases. Many other innovative approaches including biosynthesized nanoparticles have been evaluated and proposed at various scales, but in fact there are some barriers for practical application of nanotechnology in soil-plant system, including safety and regulatory concerns, efficient delivery at field levels, and consumer acceptance. Finally, we outlined the policy options and actions required for sustainable agricultural productivity, and proposed various research pathways that may help to overcome the upcoming challenges regarding practical implications of nanotechnology. [Display omitted] • Nanotechnology, an innovative scientific field, is now applied in almost all scientific studies. • Integrated application of nanotechnology with precision agriculture can sustain the agricultural production. • Various kinds of nano-sensors and biosynthesized nanoparticles are applied in agriculture for better crop productivity. • Excessive nanoparticles application is a serious concern due to their unknown release in environmental compartments. • Toxicity concerns causing nanotechnology application limited, especially related to human health should be investigated. [ABSTRACT FROM AUTHOR]

A two-year experiment was conducted at Student Research Farm, Department of Agronomy, University of Agriculture, Faisalabad (31.4533° N, 73.0585° E) during 2020 and repeated in 2021 for the accuracy of the results. The treatments were T0 Control (recommended fertilizers at 20:60 NP kg ha−1), T1: 50% of recommended vermicompost (FYM) + 50% of recommended fertilizers, T2: 25% of recommended vermicompost (FYM) + 25% of recommended compost (FYM) + 50% of recommended fertilizers, T3: 50% of recommended vermicompost (wheat straw) + 50% of recommended fertilizers, T4: 25% of recommended vermicompost (wheat straw) + 25% of recommended compost (wheat straw) + 50% of recommended fertilizers, T5: 50% of recommended vermicompost (rice straw) + 50% of recommended fertilizers and T6: 25% of vermicompost (rice straw) + 25% of recommended compost (rice straw) + 50% of recommended fertilizers. It was concluded from this study that 50% vermicompost (produced from FYM, rice and wheat straw) mixed with 50% recommended fertilizers showed excellent results. 25% vermicompost (produced from FYM, rice and wheat straw) and 25% compost (produced from farmyard manure, rice straw and wheat straw) mixed with 50% recommended fertilizers showed intermediate results, whereas control showed minimum results in the mungbean crop and soil fertility decreased in the T0 treatment. [ABSTRACT FROM AUTHOR]

Salinity is a global problem, and almost more than 20% of the total cultivated area of the world is affected by salt stress. Phytoremediation is one of the most suitable practices to combat salinity and recently biochar has showed the tremendous potential to alleviate salt-affected soils and enhance vegetation. Trees improve the soil characteristics by facilitating the leaching of salts and releasing organic acids in soil. Moreover, in the presence of trees, higher transpiration rates and lower evaporation rates are also helpful in ameliorating salt affected soils. This study was designed to check the effect of different levels of biochar on the morph-physiological characteristics of three important agroforestry tree species: Eucalyptus camaldulensis, Vachellia nilotica, and Dalbergia sissoo, in saline soils. Farmyard manure biochar was applied at the rate of 3% (w/w), 6% (w/w), and 9% (w/w) to find appropriate levels of biochar for promoting the early-stage trees growth under saline conditions. Results of the current study revealed that maximum shoot length (104.77 cm), shoot dry weight (23.72 g), leaves dry weight (28.23 g), plant diameter (12.32 mm), root length (20.89 cm), root dry weight (18.90 g), photosynthetic rate (25.33 μ moles CO2 m-2s-1) and stomatal conductance (0.12 mol H2O m-2 s-1) were discovered in the plants of Eucalyptus camaldulensis at the rate of 6% (w/w). All tree species showed better results for growth and physiological characteristics when biochar was applied at the rate of 6% (w/w). In comparison, a decreasing trend in growth parameters was found in the excessive amount of biochar when the application rate was increased from 6% (w/w) to 9% (w/w) for all three species. So, applying an appropriate level of biochar is important for boosting plant growth in saline soils. Among different tree species, Vachellia nilotica and Eucalyptus camaldulensis both showed very promising results to remediate salt affected soils with Vachellia nilotica showing maximum potential to absorb sodium ions. [ABSTRACT FROM AUTHOR]

Background: Pink bollworm, Pectinophora gossypiella (Lepidoptera: Gelechiidae) is a native pest of Asia and preferably invasion on cotton (Gossypium hirsutum L.) crop as a commendatory host plant. Commercially, G. hirsutum is known as white gold and is an important cash crop all over the globe. Limited studies were published to focus on certain dietary compositions against different cotton pests. Therefore, the present study was undertaken in the laboratory under controlled conditions (temperature: 27 ± 2°C and relative humidity: 60 ± 10%) to determine the impact of three different treatment diets (wheat germ meal, okra, and chickpea) on the biological aspects (lifetime, developmental period) of P. gossypiella. Results: Results revealed that the shortest larval time of P. gossypiella was observed on the okra feed diet while the longest period was recorded on the wheat germ diet. Meanwhile, the pupation delay was noted on the wheat germ diet. The dietary influence was also observed on adult stages of female and male P. gossypiella (43.00 and 37.50 days respectively) and compared with a standard diet (56.50 and 52.50 days respectively). Furthermore, larval weighed more on the okra and chickpea diet followed by the wheat germ diet, whereas highest pupal weight was observed on the standard diet followed by the chickpea diet and okra diet. Conclusion: Developmental parameters were significantly variant across all treatment diets, whereas the higher significant difference was reported on the okra diet. Therefore, the existing data of this study offers fruitful interventions for the future as a modified diet for large-scale and rapid mass production of P. gossypiella larvae. [ABSTRACT FROM AUTHOR]

• A critical review of photocatalytic and biodesulphurization methods is presented. • The mechanism of coal desulphurization is critically discussed. • Challenges faced in photocatalytic desulphurization are highlighted. • A hybrid system for biodesulphurization in synergy with CO 2 mitigation is proposed. • Cost analysis of simultaneous biodesulphurization and CO 2 consumption is reviewed. Developing efficient methods for deep desulphurization of commercial fuel is of utmost importance due to the environmental impact of sulphur and stringent government regulations for sulphur-free fuel. This review highlighted the significance of photo-assisted biocatalytic desulphurization of coal and introduced novel strategies that combine coal desulphurization with CO 2 mitigation. The interactions between microbes and the mechanisms underlying the biodesulphurization of coal were thoroughly discussed. Furthermore, the effect of coal structure and porosity on the desulphurization of inorganic sulphur was analyzed. It is acknowledged that achieving high catalytic efficiency and stability of the catalyst during photocatalytic desulphurization remains a challenge. The review also identified microbial species that are most suitable for simultaneous biodesulphurization and CO 2 mitigation, taking into account their mutualistic growth patterns. Besides, the mechanisms and cost-benefit analysis of coal biodesulphurization with high CO 2 consumption by bacterial communities in a hybrid system were further examined. The insights provided in this review can offer a comprehensive understanding of the design of a hybrid system capable of self-capturing CO 2 from polluted atmospheres and utilizing it in a reactor for cost-effective coal biodesulphurization, which holds great potential for combating smog and global warming. [ABSTRACT FROM AUTHOR]