Breathing in danger: Understanding the multifaceted impact of air pollution on health impacts.

Air pollution, a pervasive environmental threat that spans urban and rural landscapes alike, poses significant risks to human health, exacerbating respiratory conditions, triggering cardiovascular problems, and contributing to a myriad of other health complications across diverse populations worldwide. This article delves into the multifarious impacts of air pollution, utilizing cutting-edge research methodologies and big data analytics to offer a comprehensive overview. It highlights the emergence of new pollutants, their sources, and characteristics, thereby broadening our understanding of contemporary air quality challenges. The detrimental health effects of air pollution are examined thoroughly, emphasizing both short-term and long-term impacts. Particularly vulnerable populations are identified, underscoring the need for targeted health risk assessments and interventions. The article presents an in-depth analysis of the global disease burden attributable to air pollution, offering a comparative perspective that illuminates the varying impacts across different regions. Furthermore, it addresses the economic ramifications of air pollution, quantifying health and economic losses, and discusses the implications for public policy and health care systems. Innovative air pollution intervention measures are explored, including case studies demonstrating their effectiveness. The paper also brings to light recent discoveries and insights in the field, setting the stage for future research directions. It calls for international cooperation in tackling air pollution and underscores the crucial role of public awareness and education in mitigating its impacts. This comprehensive exploration serves not only as a scientific discourse but also as a clarion call for action against the invisible but insidious threat of air pollution, making it a vital read for researchers, policymakers, and the general public.

Interaction of titanium dioxide nanoparticles with PVC-microplastics and chromium counteracts oxidative injuries in Trachyspermum ammi L. by modulating antioxidants and gene expression.

The emergence of polyvinyl chloride (PVC) microplastics (MPs) as pollutants in agricultural soils is increasingly alarming, presenting significant toxic threats to soil ecosystems. Ajwain (Trachyspermum ammi L.), a plant of significant medicinal and culinary value, is increasingly subjected to environmental stressors that threaten its growth and productivity. This situation is particularly acute given the well-documented toxicity of chromium (Cr), which has been shown to adversely affect plant biomass and escalate risks to the productivity of such economically and therapeutically important species. The present study was conducted to investigate the individual effects of different levels of PVC-MPs (0, 2, and 4 mg L-1) and Cr (0, 150, and 300 mg kg-1) on various aspects of plant growth. Specifically, we examined growth and biomass, photosynthetic pigments, gas exchange attributes, oxidative stress responses, antioxidant compound activity (both enzymatic and nonenzymatic), gene expression, sugar content, nutritional status, organic acid exudation, and Cr accumulation in different parts of Ajwain (Trachyspermum ammi L.) seedlings, which were also exposed to varying levels of titanium dioxide (TiO2) nanoparticles (NPs) (0, 25, and 50 µg mL-1). Results from the present study showed that the increasing levels of Cr and PVC-MPs in soils significantly decreased plant growth and biomass, photosynthetic pigments, gas exchange attributes, sugars, and nutritional contents from the roots and shoots of the plants. Conversely, increasing levels of Cr and PVC-MPs in the soil increased oxidative stress indicators in term of malondialdehyde, hydrogen peroxide, and electrolyte leakage, and also increased organic acid exudation pattern in the roots of T. ammi seedlings. Interestingly, the application of TiO2-NPs counteracted the toxicity of Cr and PVC-MPs in T. ammi seedlings, leading to greater growth and biomass. This protective effect is facilitated by the NPs' ability to sequester reactive oxygen species, thereby reducing oxidative stress and lowering Cr concentrations in both the roots and shoots of the plants. Our research findings indicated that the application of TiO2-NPs has been shown to enhance the resilience of T. ammi seedlings to Cr and PVC-MPs toxicity, leading to not only improved biomass but also a healthier physiological state of the plants. This was demonstrated by a more balanced exudation of organic acids, which is a critical response mechanism to metal stress.

Liquid fertilizers produced by microwave-assisted acid hydrolysis of livestock and poultry wastes and their effects on hot pepper cultivation.

Liquid fertilizers (LFs) produced by microwave-assisted acid hydrolysis of livestock and poultry wastes were applied to potted hot pepper (Capsicum annuum L.) to evaluate their potential to be used as amino acid LFs. A preliminary experiment was conducted to determine the optimum acid-hydrolysis conditions for producing LFs from a mixture of pig hair and faeces (P) and another mixture of chicken feathers and faeces (C). Two LFs were produced under the optimum acid-hydrolysis conditions (acidification by sulphuric acid (7.5 mol L-1) in a microwave (200 W) for 90 minutes), and a commercial amino acid LF (Guo Guang (GG)) was used for comparison. P, C and GG fertilizers were tested in potted hot pepper cultivation at two doses, whereas no fertilizer application served as the control (CK). P and C fertilizers significantly increased the fruit yield compared with GG fertilizer, particularly at the higher dose. Moreover, the treatments improved the fruit vitamin C and soluble sugar contents in the order of C > P > GG compared with CK. These results could be attributed to more types of amino acids in C fertilizer than in P and GG fertilizers. The results also indicated that the prepared fertilizers could significantly increase the shoot and root dry weight, soil available nitrogen and phosphorus contents and nitrogen, phosphorus, and potassium (NPK) uptake by plants compared with CK. In conclusion, microwave-assisted acid hydrolysis could effectively convert unusable wastes into valuable fertilizers comparable or even superior to commercial fertilizers.

Alkaline and acidic soil constraints on iron accumulation by Rice cultivars in relation to several physio-biochemical parameters.

Agricultural production is severely limited by an iron deficiency. Alkaline soils increase iron deficiency in rice crops, consequently leading to nutrient deficiencies in humans. Adding iron to rice enhances both its elemental composition and the nutritional value it offers humans through the food chain. The purpose of the current pot experiment was to investigate the impact of Fe treatment in alkaline (pH 7.5) and acidic (pH 5.5) soils to introduce iron-rich rice. Iron was applied to the plants in the soil in the form of an aqueous solution of FeSO4 with five different concentrations (100, 200, 300, 400, and 500 mM). The results obtained from the current study demonstrated a significant increase in Fe content in Oryza sativa with the application of iron in both alkaline and acidic pH soils. Specifically, Basmati-515, one of the rice cultivars tested, exhibited a notable 13% increase in iron total accumulation per plant and an 11% increase in root-to-shoot ratio in acidic soil. In contrast to Basmati-198, which demonstrated maximum response in alkaline soil, Basmati-515 exhibited notable increases in all parameters, including a 31% increase in dry weight, 16% increase in total chlorophyll content, an 11% increase in CAT (catalase) activity, 7% increase in APX (ascorbate peroxidase) activity, 26% increase in POD (peroxidase) activity, and a remarkable 92% increase in SOD (superoxide dismutase) in acidic soil. In alkaline soil, Basmati-198 exhibited respective decreases of 40% and 39% in MDA and H2O2 content, whereas Basmati-515 demonstrated a more significant decrease of 50% and 67% in MDA and H2O2 in acidic soil. These results emphasize the potential for targeted soil management strategies to improve iron nutrition and address iron deficiency in agricultural systems. By considering soil conditions, it is possible to enhance iron content and promote its availability in alkaline and acidic soils, ultimately contributing to improved crop nutrition and human health.

Genome-wide identification of CCO gene family in cucumber (Cucumis sativus) and its comparative analysis with A. thaliana.

Carotenoid cleavage oxygenase (CCO) is an enzyme capable of converting carotenoids into volatile, aromatic compounds and it plays an important role in the production of two significant plant hormones, i.e., abscisic acid (ABA) and strigolactone (SL). The cucumber plant genome has not been mined for genomewide identification of the CCO gene family. In the present study, we conducted a comprehensive genome-wide analysis to identify and thoroughly examine the CCO gene family within the genomic sequence of Cucumis sativus L. A Total of 10 CCO genes were identified and mostly localized in the cytoplasm and chloroplast. The CCO gene is divided into seven subfamilies i.e. 3 NCED, 3 CCD, and 1 CCD-like (CCDL) subfamily according to phylogenetic analysis. Cis-regulatory elements (CREs) analysis revealed the elements associated with growth and development as well as reactions to phytohormonal, biotic, and abiotic stress conditions. CCOs were involved in a variety of physiological and metabolic processes, according to Gene Ontology annotation. Additionally, 10 CCO genes were regulated by 84 miRNA. The CsCCO genes had substantial purifying selection acting upon them, according to the synteny block. In addition, RNAseq analysis indicated that CsCCO genes were expressed in response to phloem transportation and treatment of chitosan oligosaccharides. CsCCD7 and CsNCED2 showed the highest gene expression in response to the exogenous application of chitosan oligosaccharides to improve cold stress in cucumbers. We also found that these genes CsCCD4a and CsCCDL-a showed the highest expression in different plant organs with respect to phloem content. The cucumber CCO gene family was the subject of the first genome-wide report in this study, which may help us better understand cucumber CCO proteins and lay the groundwork for the gene family's future cloning and functional investigations.

Foliar application of iron-lysine to boost growth attributes, photosynthetic pigments and biochemical defense system in canola (Brassica napus L.) under cadmium stress.

In the current industrial scenario, cadmium (Cd) as a metal is of great importance but poses a major threat to the ecosystem. However, the role of micronutrient - amino chelates such as iron - lysine (Fe - lys) in reducing Cr toxicity in crop plants was recently introduced. In the current experiment, the exogenous applications of Fe - lys i.e., 0 and10 mg L - 1, were examined, using an in vivo approach that involved plant growth and biomass, photosynthetic pigments, oxidative stress indicators and antioxidant response, sugar and osmolytes under the soil contaminated with varying levels of Cd i.e., 0, 50 and 100 µM using two different varieties of canola i.e., Sarbaz and Pea - 09. Results revealed that the increasing levels of Cd in the soil decreased plant growth and growth-related attributes and photosynthetic apparatus and also the soluble protein and soluble sugar. In contrast, the addition of different levels of Cd in the soil significantly increased the contents of malondialdehyde (MDA) and hydrogen peroxide (H2O2), which induced oxidative damage in both varieties of canola i.e., Sarbaz and Pea - 09. However, canola plants increased the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and non-enzymatic compounds such as phenolic, flavonoid, proline, and anthocyanin, which scavenge the over-production of reactive oxygen species (ROS). Cd toxicity can be overcome by the supplementation of Fe - lys, which significantly increased plant growth and biomass, improved photosynthetic machinery and sugar contents, and increased the activities of different antioxidative enzymes, even in the plants grown under different levels of Cd in the soil. Research findings, therefore, suggested that the Fe - lys application can ameliorate Cd toxicity in canola and result in improved plant growth and composition under metal stress.

Nitric oxide confers cadmium tolerance in fragrant rice by modulating physio-biochemical processes, yield attributes, and grain quality traits.

Cadmium (Cd) stress causes serious disruptions in plant metabolism, physio-biochemical processes, crop yield, and quality characters. Nitric oxide (NO) improves the quality features and nutritional contents of fruit plants. However, how NO confers Cd toxicity in fragrant rice plants, is sparse. Hence, the present study investigated the effects of 50 µM NO donor sodium nitroprusside (SNP) on physio-biochemical processes, plant growth attributes, grain yield, and quality traits of fragrant rice under Cd stress (100 mg kg-1 soil). The results revealed that Cd stress diminished rice plant growth, impaired photosynthetic apparatus and antioxidant defense system, and deteriorated the grain quality traits. However, foliar application of SNP mitigated Cd stress by improving plant growth and gas exchange attributes. Higher electrolyte leakage (EL) was accompanied with elevated levels of malondialdehyde (MDA) and hydrogen peroxide (H2O2) under Cd stress; however, exogenous application of SNP reduced them. The activities and relative expression levels of enzymatic antioxidants; superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX) and non-enzymatic antioxidants, glutathione (GSH) contents were reduced by Cd stress, while SNP application regulated their activity and transcript abundances. SNP application improved fragrant rice grain yield and 2-acetyl-1-pyrroline content by 57.68 % and 75.54 % respectively, which is concomitant with higher biomass accumulation, photosynthetic efficiency, photosynthetic pigment contents, and an improved antioxidant defense system. Collectively, our results concluded that SNP application regulated the fragrant rice plant physio-biochemical processes, yield traits and grain quality characters under Cd-affected soil.

Drought-tolerant Pseudomonas sp. showed differential expression of stress-responsive genes and induced drought tolerance in Arabidopsis thaliana.

The growth and persistence of rhizobacteria in soils are highly impacted by moisture stress. In this study, we report the first transcript analysis of four Pseudomonas strains (PS1, PS2, PS3, and PS4) isolated from the root-soil interface of rice and maize associated with different moisture levels during water deprivation. Filtered Pseudomonas sp. cells incubated at low (RH10%) and high (RH85%) relative humidity showed decreased survival of all Pseudomonas sp. at RH10% when compared with RH85%. RT-PCR showed differential expression of treS (trehalose synthase), rpoS (sigma factor), mucA (alginate regulatory gene), and fliM (flagellar motor switch protein gene) in response to exposure to RH10%. However, molecular fingerprinting and nutrient assimilation profile of Pseudomonas strains demonstrated genetic and physiological variation between the four strains irrespective of water regime and host. In vitro testing of these strains showed ACC deaminase activity and gibberellic acid, abscisic acid, indole acetic acid, and exopolysaccharide production. We determined that 50 µl of 1.2 × 103 CFU ml-1 of these Pseudomonas strains was enough to protect Arabidopsis plants against drought stress in a pot experiment. Inoculated plants increased their root colonization ability and biomass; however, PS2 showed higher survival (95%), relative water content (59%), chlorophyll (30%), glycine betaine (38%), proline (23%), and reduced MDA (43%) in shoots than irrigated control under induced water deprivation. It can be concluded that all Pseudomonas strains were effective in mitigating drought stress, however, PS2 appears to impart more resistance to drought than the other strains by upregulating key defense mechanisms.

Response of cauliflower (Brassica oleracea L.) to nitric oxide application under cadmium stress.

Soil contamination with cadmium (Cd) is a persistent threat to crop production worldwide. The present study examined the putative roles of nitric oxide (NO) in improving Cd-tolerance in cauliflower (Brassica oleracea L.). The present study was conducted using four different genotypes of B. oleracea named as FD-3, FD-4, FD-2 and Ceilo Blanco which were subjected to the Cd stress at various concentrations i.e., 0, 5, 10 and 20 µM with or without the application of NO i.e., 0.10 mM in the sand containing nutrient Hoagland's solution. Our results illustrated that the increasing levels of Cd in the sand, significantly (P < 0.05) decreased shoot length, root length, shoot fresh weight, root fresh weight, shoot dry weight, root dry weight, germination percentage, germination index, mean germination time, time to 50% germination, chlorophyll a, chlorophyll b, total chlorophyll and carotenoid contents in all genotypes of B. oleracea. The concentration of malondialdehyde (MDA) and Cd accumulation (roots and shoots) increased significantly (P < 0.05) under the increasing levels of Cd in all genotypes of B. oleracea while antioxidant (enzymatic or non-enzymatic) capacity and nutritional status of the plants was decreased with varying levels of Cd in the sand. From all studied genotypes of B. oleracea, Ceilo Blanco and FD-4 was found to be most sensitive species to the Cd stress under the same levels of the Cd in the medium while FD-2 and FD-3 showed more tolerance to the Cd stress compared to all other genotypes of B. oleracea. Although, toxic effect of Cd in the sand can overcome by the application of NO which not only increased plant growth and nutrients accumulation but also decreased the oxidative damage to the membranous bounded organelles and also Cd accumulation in various parts of the plants in all genotypes of B. oleracea. Hence, it was concluded that application of NO can overcome Cd toxicity in B. oleracea by maintaining the growth regulation and nutritional status of the plant and overcome oxidative damage induced by Cd toxicity in all genotypes of B. oleracea.

Antifungal activity of Zinc nitrate derived nano Zno fungicide synthesized from Trachyspermum ammi to control fruit rot disease of grapefruit.

Grapefruit (Citrus paradisi) is a widely grown citrus and its fruit is affected by a variety of biotic and abiotic stress. Keeping in view the hazardous effects of synthetic fungicides, the recent trend is shifting towards safer and eco-friendly control of fruit diseases. The present study was aimed to diagnose the fruit rot disease of grapefruit and its control by using zinc oxide green nanoparticles (ZnO NPs). Fruit rot symptoms were observed in various grapefruit growing sites of Pakistan. Diseased samples were collected, and the disease-causing pathogen was isolated. Following Koch's postulates, the isolated pathogen was identified as Rhizoctonia solani. For eco-friendly control of this disease, ZnO NPs were prepared in the seed extract of Trachyspermum ammi and characterized. Fourier transform infrared spectroscopy (FTIR) of these NPs described the presence of stabilizing and reducing compounds such as phenols, aldehyde and vinyl ether, especially thymol (phenol). X-ray diffraction (XRD) analysis revealed their crystalline nature and size (48.52 nm). Energy dispersive X-ray (EDX) analysis elaborated the presence of major elements in the samples, while scanning electron microscopy (SEM) confirmed the morphology of bio fabricated NPs. ZnO NPs exhibited very good anti-fungal activity and the most significant fungal growth inhibition was observed at 1.0 mg/ml concentration of green NPs, in vitro and in vivo. These findings described that the bioactive constituents of T. ammi seed extract can effectively reduce and stabilize ZnO NPs. It is a cost-effective method to successfully control the fruit rot disease of grapefruit.

Chromium-resistant Staphylococcus aureus alleviates chromium toxicity by developing synergistic relationships with zinc oxide nanoparticles in wheat.

Chromium (Cr) is a toxic heavy metal that contaminates soil and water resources after its discharge from different industries. It can act as carcinogen and mutagen for biological systems. Microbe-assisted phytoremediation is one of the most emergent and environment friendly technique used for detoxification of Cr from Cr-contaminated soils. In this study, wheat as a test crop was grown under varying stress levels (0, 50, 100 and 200 mg/kg) of Cr in a pot experiment under a complete randomized design. Alleviative role of Staphylococcus aureus strain K1 was assessed by applying as a treatment in different combinations of zinc oxide nanoparticles (0, 50, 100 mg/L). Growth and yield attributes data presented nurturing impact of bacterial inoculation and ZnO NPs in improvement of wheat defense system by decreasing Cr toxicity. Increase in chlorophyll and carotenoids contents, antioxidant enzymes (SOD, POD, APX, CAT) activities and nutrient uptake also confirmed the mitigative potential of bacterial inoculation when applied solely or in combination with ZnO NPs. The Cr accumulation in different parts of plant was significantly reduced with the application of NPs and S. aureus strain K1. Taken together, the results showed that combined application of Staphylococcus aureus strain K1 and ZnO NPs detoxifies the effects of Cr on wheat plants and boosts its growth, physiology and defense system.

A Novel Distachionate from Breynia distachia Treats Inflammations by Modulating COX-2 and Inflammatory Cytokines in Rat Liver Tissue.

Breynia distachia is a plant of genus Breynia belonging to family Phyllanthaceae. This study was conducted to isolate and examine the anti-inflammatory attributes of the roots of Breynia distachia. Methanol extract from roots were prepared by simple maceration. For phytochemical studies, isolation, purification, structure elucidation, metal analysis, total phenolic content, and solubility test were done by chromatographic and spectroscopic techniques. Anti-inflammatory activity was evaluated by cotton pallet edema model and carrageenan paw edema model, and antioxidant potential was evaluated by DPPH, FRAP, and ABTS antioxidants assays. Metal analysis of BD.Me revealed the presence of Na > Mg > K > Mn > Fe = Zn in respective order. Four phytochemicals such as gallic acid, quercetin, sinapic acid, and p-coumaric acid are found in Breynia distachia. Quercetin is present in relatively larger quantity, and shows antioxidant activity by reducing the ferric iron to ferrous iron. Novel distachionate shows high antioxidant activity in ABTS assay by reducing reactive oxygen species. Quantitative or qualitative analysis performed by HPLC indicates the ascending peaks or presence of secondary products (metabolites) respectively. Histopathology analysis of liver, spleen, heart, and kidney was done, revealing mild inflammations in spleen and liver, and no cytotoxicity in heart and kidney. Oral administration of BD.Me and ditachionate significantly inhibits the carrageenan and cotton pellet-induced paw edema in 1st and 2nd h with (ns = p > 0.05) than control. After 3rd, 4th, 5th, and 6th h, BD.Me and ditachionate showed inhibition of paw edema in a highly significant (*** = p < 0.001) manner as compared to control. In cotton-pellet edema model, distachionate shows a %inhibition of 57.3% at a dose level of 5 mg/kg. Docking values obtained from distachionate-COX-2 complex suggest a potent inhibitor evaluated for this protein. The distachionate shows effective anti-inflammatory activity. Methanol extracts of roots showed significant lipoxygenase inhibitory activity by IC50 values of 155.7 ± 0.55 and 132.9 ± 0.33 µg/mL. Data from various in vitro and in vivo models suggest that novel distachionate isolated from Breynia distachia shows strong antioxidant and anti-inflammatory activities; it should be further studied for the exploration of its medicinal potential.

Molybdenum improves 2-acetyl-1-pyrroline, grain quality traits and yield attributes in fragrant rice through efficient nitrogen assimilation under cadmium toxicity.

Cadmium (Cd) toxicity causes severe perturbations in nitrogen (N) uptake and assimilation, and thereby interrupts normal plant growth. Molybdenum (Mo), a necessary trace element, plays important roles in N metabolism through regulating N assimilatory enzymes activities and expressions in higher plants. Taking this into account, a pot experiment was performed to explore the role of Mo in alleviating Cd-induced inhibitory effects on physio-biochemical processes, N metabolism, yield attributes and grain quality characters of two fragrant rice cultivars; Guixiangzhan and Meixiangzhan-2. Both the fragrant rice cultivars were treated with two levels of each Cd concentrations (0 and 100 mg/kg) and Mo treatments (0 and 0.15 mg/kg). The results revealed that Cd toxicity significantly reduced (p < 0.05) plant dry biomass, gaseous exchange attributes, chlorophyll contents, N utilizing and assimilatory enzymes activities, 2-acetyl-1-pyrroline (2AP) contents and grain yield in both cultivars; however, more severe inhibitions were observed in Meixiangzhan-2 than Guixiangzhan. Nevertheless, Mo application alleviated Cd stress and enhanced 2AP content and grain yield by 75.05% and 67.94% in Guixiangzhan and 87.71% and 83.51% in Meixiangzhan-2, respectively compared with no Mo application. Moreover, Mo application improved photosynthesis, chloroplast configuration, soluble protein and proline contents and also strengthened the N assimilatory pathway through efficient NO3- utilization, higher nitrate reductase, nitrite reductase, glutamine synthetase and glutamate synthase activities and transcript levels under Cd stress. Collectively, our results imply that Mo-induced enhancement in N utilization and assimilation improved yield and grain quality characters of fragrant rice cultivars under Cd stress.

Diversity and Taxonomic Distribution of Endophytic Bacterial Community in the Rice Plant and Its Prospective.

Endophytic bacterial communities are beneficial communities for host plants that exist inside the surfaces of plant tissues, and their application improves plant growth. They benefit directly from the host plant by enhancing the nutrient amount of the plant's intake and influencing the phytohormones, which are responsible for growth promotion and stress. Endophytic bacteria play an important role in plant-growth promotion (PGP) by regulating the indirect mechanism targeting pest and pathogens through hydrolytic enzymes, antibiotics, biocontrol potential, and nutrient restriction for pathogens. To attain these benefits, firstly bacterial communities must be colonized by plant tissues. The nature of colonization can be achieved by using a set of traits, including attachment behavior and motility speed, degradation of plant polymers, and plant defense evasion. The diversity of bacterial endophytes colonization depends on various factors, such as plants' relationship with environmental factors. Generally, each endophytic bacteria has a wide host range, and they are used as bio-inoculants in the form of synthetic applications for sustainable agriculture systems and to protect the environment from chemical hazards. This review discusses and explores the taxonomic distribution of endophytic bacteria associated with different genotypes of rice plants and their origin, movement, and mechanism of PGP. In addition, this review accentuates compressive meta data of endophytic bacteria communities associated with different genotypes of rice plants, retrieves their plant-growth-promoting properties and their antagonism against plant pathogens, and discusses the indication of endophytic bacterial flora in rice plant tissues using various methods. The future direction deepens the study of novel endophytic bacterial communities and their identification from rice plants through innovative techniques and their application for sustainable agriculture systems.

The Role of Membrane Transporters in Plant Growth and Development, and Abiotic Stress Tolerance.

The proteins of membrane transporters (MTs) are embedded within membrane-bounded organelles and are the prime targets for improvements in the efficiency of water and nutrient transportation. Their function is to maintain cellular homeostasis by controlling ionic movements across cellular channels from roots to upper plant parts, xylem loading and remobilization of sugar molecules from photosynthesis tissues in the leaf (source) to roots, stem and seeds (sink) via phloem loading. The plant's entire source-to-sink relationship is regulated by multiple transporting proteins in a highly sophisticated manner and driven based on different stages of plant growth and development (PG&D) and environmental changes. The MTs play a pivotal role in PG&D in terms of increased plant height, branches/tiller numbers, enhanced numbers, length and filled panicles per plant, seed yield and grain quality. Dynamic climatic changes disturbed ionic balance (salt, drought and heavy metals) and sugar supply (cold and heat stress) in plants. Due to poor selectivity, some of the MTs also uptake toxic elements in roots negatively impact PG&D and are later on also exported to upper parts where they deteriorate grain quality. As an adaptive strategy, in response to salt and heavy metals, plants activate plasma membranes and vacuolar membrane-localized MTs that export toxic elements into vacuole and also translocate in the root's tips and shoot. However, in case of drought, cold and heat stresses, MTs increased water and sugar supplies to all organs. In this review, we mainly review recent literature from Arabidopsis, halophytes and major field crops such as rice, wheat, maize and oilseed rape in order to argue the global role of MTs in PG&D, and abiotic stress tolerance. We also discussed gene expression level changes and genomic variations within a species as well as within a family in response to developmental and environmental cues.

Morpho-physiological traits, gaseous exchange attributes, and phytoremediation potential of jute (Corchorus capsularis L.) grown in different concentrations of copper-contaminated soil.

Jute (Corchorus capsularis L.) is the most commonly used natural fiber as reinforcement in green composites and, due to its huge biomass, deep rooting system, and metal tolerance in stressed environments, it is an excellent candidate for the phytoremediation of different heavy metals. Therefore, the present study was carried out to examine the growth, antioxidant capacity, gaseous exchange attributes, and phytoremediation potential of C. capsularis grown at different concentrations of Cu (0, 100, 200, 300, and 400 mg kg-1) in a glass house environment. The results illustrate that C. capsularis can tolerate Cu concentrations of up to 300 mg kg-1 without significant decreases in growth or biomass, but further increases in Cu concentration (i.e., 400 mg kg-1) lead to significant reductions in plant growth and biomass. The photosynthetic pigments and gaseous exchange attributes in the leaves of C. capsularis decreased as the Cu concentration in the soil increased. Furthermore, high concentrations of Cu in the soil caused lipid peroxidation by increasing the malondialdehyde content in the leaves. This implies that elevated Cu levels cause oxidative damage in C. capsularis. Antioxidants, such as superoxidase dismutase and peroxidase, come into play to scavenge the reactive oxygen species which are generated as a result of oxidative stress. In the present study, the concentrations of Cu in different parts of the plant (the roots, leaves, stem core, and fibers) were also investigated at four different stages of the life cycle of C. capsularis, i.e., 30, 60, 90, and 120 days after sowing (DAS). The results of this investigation reveal that, in the earlier stages of the growth, Cu was highly accumulated in the belowground parts of the plant while little was transported to the aboveground parts. Contrastingly, at a fully mature stage of the growth (120 DAS), it was observed that the majority of Cu was transported to the aboveground parts of the plant and very little accumulated in the belowground parts. The results also show a progressive increase in Cu uptake in response to increasing Cu concentrations in the soil, suggesting that C. capsularis is a potential bio-resource for the phytoremediation of Cu in Cu-contaminated soil.

Appraising growth, oxidative stress and copper phytoextraction potential of flax (Linum usitatissimum L.) grown in soil differentially spiked with copper.

Flax (Linum usitatissimum L.) is one of the oldest predominant industrial crops grown for seed, oil and fiber. The present study was executed to evaluate the morpho-physiological traits, biochemical responses, gas exchange parameters and phytoextraction potential of flax raised in differentially copper (Cu) spiked soil viz (0, 200, 400 and 600 mg Cu kg-1 soil) under greenhouse pot experiment. The results revealed that flax plants were able to grow up to 400 mg kg-1 Cu level without showing significant growth inhabitation while, further inference of Cu (600 mg kg-1) in the soil prominently inhibited flax growth and biomass accumulation. Compared to the control, contents of proline and malondialdehyde (MDA) were increased by 160.0% and 754.1% accordingly, at 600 mg Cu kg-1 soil level. The Cu-induced oxidative stress was minimized by the enhanced activities of superoxide dismutase (SOD) by 189.2% and guaiacol peroxidase (POD) by 300.8% in the leaves of flax at 600 mg Cu kg-1 soil level, compared to the untreated control. The plant Cu concentration was determined at 35, 70, 105 and 140 days after sowing (DAS) and results depicted that 16.9 times higher Cu concentration was accumulated in flax roots while little (14.9 times) was transported to the shoots at early stage of growth, i.e. 35 DAS. While at 140 DAS, Cu was highly (21.7 times) transported to the shoots while, only 12.3 times Cu was accumulated in the roots at 600 mg Cu kg-1 soil level, compared to control. Meanwhile, Cu uptake by flax was boosted up to 253 mg kg-1 from the soil and thereby extracted 43%, 39% and 41% of Cu at 200, 400 and 600 mg Cu kg-1 soil level, compared to initial Cu concentration. Therefore, study concluded that flax has a great potential to accumulate high concentration of Cu in its shoots and can be utilized as phytoremediation material when grown in Cu contaminated soils.

Soil phosphorus transformation characteristics in response to molybdenum supply in leguminous crops.

Phosphorus (P) is one of the most restrictive essential elements to crop growth and development due to less availability in the soil system. Previous studies have reported the synergistic effects between molybdenum (Mo) and P fertilizer on P uptake in various crops. However, an induced long term effect of Mo on soil P dynamics in the rhizosphere and non-rhizosphere has not been reported yet in leguminous crops. In this study, a long term field experiment was conducted to explore the P transformation characteristics and bioavailability in Mo-deficient (-Mo) and Mo-enriched (+Mo) soil under leguminous (broad bean-soybean) cropping system. The results indicated that long-term Mo application increased the plant dry matter accumulation (14.23%-35.27%, for broad bean; 24.40%-37.46%, for soybean) from March-September. In rhizosphere soil, the percent decrease in pH (8.10%) under +Mo treatment of the soybean crop was recorded more during September as compared to broad bean crop. Under Mo supply, H2O-Pi fraction increased up to 28.53% and 43.67% while for NaHCO3-Pi this increase was up to 5.61% and 11.98%, respectively in the rhizosphere soil of broad bean and soybean, whereas, residual-P exhibited the highest proportion of P fractions. Moreover, compared with -Mo, +Mo treatments significantly increased the soil acid phosphatase (broad bean = 17.43 µmol/d/g; soybean = 28.60 µmol/d/g), alkaline phosphatase (broad bean = 3.34 µmol/d/g; soybean 6.35 µmol/d/g) and phytase enzymes activities (broad bean = 2.45 µmol/min/g; soybean = 5.91 µmol/min/g), transcript abundance of phoN/phoC genes and microbial biomass P (MBP) in rhizosphere soil. In crux, the findings of this study suggest that long term Mo application enhanced P bioavailability through increased available P, MBP, P related enzymes activities and their genes expressions which may represent a strategy of Mo to encounter P deficiencies in the soil system.

Plant growth-promoting Bacillus sp. strain SDA-4 confers Cd tolerance by physio-biochemical improvements, better nutrient acquisition and diminished Cd uptake in Spinacia oleracea L.

Cadmium (Cd) is highly toxic metal for plant metabolic processes even in low concentration due to its longer half-life and non-biodegradable nature. The current study was designed to assess the bioremediation potential of a Cd-tolerant phytobeneficial bacterial strain Bacillus sp. SDA-4, isolated, characterized and identified from Chakera wastewater reservoir, Faisalabad, Pakistan, together with spinach (as a test plant) under different Cd regimes. Spinach plants were grown with and without Bacillus sp. SDA-4 inoculation in pots filled with 0, 5 or 10 mg kg-1 CdCl2-spiked soil. Without Bacillus sp. SDA-4 inoculation, spinach plants exhibited reduction in biomass accumulation, antioxidative enzymes and nutrient retention. However, plants inoculated with Bacillus sp. SDA-4 revealed significantly augmented growth, biomass accumulation and efficiency of antioxidative machinery with concomitant reduction in proline and MDA contents under Cd stress. Furthermore, application of Bacillus sp. SDA-4 assisted the Cd-stressed plants to sustain optimal levels of essential nutrients (N, P, K, Ca and Mg). It was inferred that the characterized Cd-tolerant PGPR strain, Bacillus sp. SDA-4 has a potential to reduce Cd uptake and lipid peroxidation which in turn maintained the optimum balance of nutrients and augmented the growth of Cd-stressed spinach. Analysis of bioconcentration factor (BCF) and translocation factor (TF) revealed that Bacillus sp. SDA-4 inoculation with spinach sequestered Cd in rhizospheric zone. Research outcomes are important for understanding morpho-physio-biochemical attributes of spinach-Bacillus sp. SDA-4 synergy which might provide efficient strategies to decrease Cd retention in edible plants and/or bioremediation of Cd polluted soil colloids.

Interactive role of zinc and iron lysine on Spinacia oleracea L. growth, photosynthesis and antioxidant capacity irrigated with tannery wastewater.

ABSTRACT: Untreated wastewater contains toxic amounts of heavy metals such as chromium (Cr), which poses a serious threat to the growth and physiology of plants when used in irrigation. Though, Cr is among the most widespread toxic trace elements found in agricultural soils due to various anthropogenic activities. To explore the interactive effects of micronutrients with amino acid chelators [iron-lysine (Fe-lys) and zinc-lysine (Zn-lys)], pot experiments were conducted in a controlled environment, using spinach (Spinacia oleracea L.) plant irrigated with tannery wastewater. S. oleracea was treated without Fe and Zn-lys (0 mg/L Zn-lys and 0 mg/L Fe-lys) and also treated with various combinations of (interactive application) Fe and Zn-lys (10 mg/L Zn-lys and 5 mg/L Fe-lys), when cultivated at different levels [0 (control) 33, 66 and 100%) of tannery wastewater in the soil having a toxic level of Cr in it. According to the results, we have found that, high concentration of Cr in the soil significantly (P < 0.05) reduced plant height, fresh biomass of roots and leaves, dry biomass of roots and leaves, root length, number of leaves, leaf area, total chlorophyll contents, carotenoid contents, transpiration rate (E), stomatal conductance (gs), net photosynthesis (PN), and water use efficiency (WUE) and the contents of Zn and Fe in the plant organs without foliar application of Zn and Fe-lys. Moreover, phytotoxicity of Cr increased malondialdehyde (MDA) contents in the plant organs (roots and leaves), which induced oxidative damage in S. oleracea manifested by the contents of hydrogen peroxide (H2O2) and membrane leakage. The negative effects of Cr toxicity could be overturned by Zn and Fe-lys application, which significantly (P < 0.05) increase plant growth, biomass, chlorophyll content, and gaseous exchange attributes by reducing oxidative stress (H2O2, MDA, EL) and increasing the activities of various antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POD) catalase (CAT) and ascorbate peroxidase (APX). Furthermore, the supplementation of Zn and Fe-lys increased the contents of essential nutrients (Fe and Zn) and decreased the content of Cr in all plant parts compared to the plants cultivated in tannery wastewater without application of Fe-lys. Taken together, foliar supplementation of Zn and Fe-lys alleviates Cr toxicity in S. oleracea by increased morpho-physiological attributes of the plants, decreased Cr contents and increased micronutrients uptake by the soil, and can be an effective in heavy metal toxicity remedial approach for other crops.