Air Pollution Tolerance Index (APTI) is an important tool to screen out plants, based on their tolerance or sensitivity level to different air pollutants. The present study has been conducted to evaluate APTI of four different plant species around polluted and unpolluted industrial site in Sfax, Tunisia. In order to determine the susceptibility level of the selected plant species, it has used four physiological and biochemical parameters like leaf relative water content, ascorbic acid content, chlorophyll content, and leaf pH to compute the APTI values. The results of the study reveal that among the four studied plant species, Olea europaea (APTI = 20.09) and Phoenix dactylifera (APTI = 17.10) are the most tolerant species, whereas Ficus carica (APTI = 8.87) and Morus alba (APTI = 7.49) are the most sensitive ones. The present study suggests that the most tolerant species, i.e., olive and date palm, can be planted in polluted sites for both air pollution abatement and aesthetic improvement. While, the sensitive species, namely common figand white Mulberry, help indicating air pollution and should be utilized as bio-indicators.

Numerous studies have documented the negative effects of ozone (O₃) on tree species in growing season, however, little is done in non-growing season. Three evergreen tree species, Phoebe bournei (Hemsl.) Yang (P. bournei), Machilus pauhoi Kanehira (M. pauhoi) and Taxus chinensis (Pilger) Rehd (T. chinensis), were exposed to non-filtered air, 100 nmol mol⁻¹ O₃ air (E1) and 150 nmol mol⁻¹ O₃ air (E2) in open-top chambers in subtropical China. In the entire period of experiment, O₃ fumigation decreased net photosynthesis rate (Pn) through stomatal limitation during the transition period from growing to non-growing season (TGN), and through non-stomatal limitation during the period of non-growing season (NGS) in all species tested. Meanwhile, O₃ fumigation reduced and delayed the resilience of Pn in all species tested during the transition period from non-growing to growing season (TNG). O₃ fumigation significantly decreased chlorophyll contents during NGS, whereas no obvious injury symptoms were observed till the end of experiment. O₃ fumigation induced increases in levels of malondialdehyde, superoxide dismutase, total phenolics and reduced ascorbic acid, and changes in four plant endogenous hormones as well in all species tested during NGS. During NGS, E1 and E2 reduced Pn by an average of 80.11% in P. bournei, 94.56% in M. pauhoi and 12.57% in T. chinensis, indicating that the O₃ sensitivity was in an order of M. pauhoi > P. bournei > T. chinensis. Overall, O₃ fumigation inhibited carbon fixation in all species tested during NGS. Furthermore, O₃-induced physiological activities also consumed the dry matter. All these suggested that elevated O₃, which is likely to come true during NGS in the future, will adversely affect the accumulation of dry matter and the resilience of Pn during TNG in evergreen tree species, and further inhibit their growth and development in the upcoming growing season.

Lead and mercury are two of the most toxic heavy metals in environments. Mesosilicate-templated magnetic nanocarbons with ascorbic acid as carbon precursor were developed through nanocasting processes. The nanocarbon showed effective magnetic separation and the maximum adsorption capacity of 80.6 and 66.3 mg/g for Hg and Pb, respectively. Langmuir model well described adsorption processes of both Hg and Pb from water. Magnetic nanocarbon could be easily separated and incinerated, reducing the volume requiring the disposal. This study indicates that mesosilicate-templated nanocarbons with easy disposal potentials may be good candidates for cleansing Hg and Pb from contaminated water.

Ascorbic acid (AA), one of the best-known reactive oxygen species (ROS) scavengers, exhibits numerous functions such as antioxidant, anti-cancer, and anti-inflammatory effects. Increasing evidence demonstrates that oxidative stress plays an important role in testicular toxicity. In the present study, we investigated the protective effect of AA against cadmium (Cd)-induced blood-testis barrier (BTB) disruption. Sprague-Dawley (SD) rats were divided into four groups: the Cd-treated group received a single dose (s.c.) of 2 mg/kg BW cadmium chloride; the AA antagonism group received an injection of AA at a dose of 400 mg/kg BW (200 mg 24 h prior to Cd treatment and 200 mg 24 h following Cd treatment); and the control groups received an equal volume of saline or an equal dose of AA. As expected, ROS expression was upregulated in the Cd-treated rats, accompanied by an increase in malondialdehyde (MDA). Interestingly, AA suppressed Cd-induced oxidative stress by decreasing the levels of ROS and MDA and increasing the activity of superoxide dismutase (SOD) and catalase (CAT). In addition, AA also reduced BTB disruption by inhibiting TGF-β3 activation and p38 MAPK phosphorylation. Significant decreases in occludin and claudin-11 expression were observed in the Cd-treated rats, whereas AA administration attenuated this effect. Moreover, testicular histopathology and transmission electron microscopy further demonstrated the protective effects of AA against Cd-induced BTB damage. In conclusion, the results of the present study suggest that AA protects BTB destruction via the inhibition of oxidative stress and the TGF-β3/p38 MAPK signalling pathway in the testis of Cd-exposed rats.

Rhenium (Re) is one of Earth’s scarcest and more largely scattered elements, with an estimate concentration of 0.4–0.6 μg kg⁻¹ in the upper crust. Still, considerable concentrations of bioavailable ReO₄⁻ ions are often found, particularly in copper-molybdenum mines, where their uptake by plants of these regions has been reported. Yet, the impact of Re on plants remains a question mark, as the only available knowledge derives from a limited investigation carried out over 60 years ago. The aim of this study was to evaluate the ecophysiological response of Brassica juncea, a species known to endure and accumulate various metals, to a broad range of Re concentrations. B. juncea plants were allowed to grow and on a substrate amended with KReO₄ to attain soil Re levels ranging from 0 to 80 mg kg⁻¹. Plants were collected 45 days after sowing for analysis. The results have shown that greater Re levels reduce growth, photosynthetic activity, soluble carbohydrate mobilization, and protein contents, and increase the plant’s oxidative stress (anthocyanins, H₂O₂, lipid peroxidation) and corresponding response (ascorbic acid, superoxide dismutase activity). Nevertheless, B. juncea exhibited a remarkable ability to endure and uptake Re, featuring shoot Re concentrations that ranged from 1615 to 24,987 mg kg⁻¹ among the 5 and 80 mg kg⁻¹ treatments.

The toxicity of Roundup Original® (GLY), a glyphosate-based herbicide widely used in crops in Mato Grosso state, was determined in hybrid fish jundiara or pintado da Amazônia. The 96 h-LC₅₀ of GLY was 13.57 mg L⁻¹. Moreover, exposure to sublethal concentrations of GLY (0, 0.37, 0.75, 2.25, 4.5, 7.5 mg L⁻¹) has not altered the survival rate (100% for all treatments). In fish liver, protein carbonyl (PC) levels as well as glutathione-S-transferase (GST) activity, reduced glutathione (GSH), and ascorbic acid (ASA) contents increased when compared to control group. Superoxide dismutase (SOD) activity was reduced and catalase (CAT) has not changed. PC content has grown in muscle and brain, and thiobarbituric acid-reactive species (TBARS) levels also increased in muscle, but in the brain, they remained unaltered. Acetylcholinesterase (AChE) activity reduced in muscle but increased in brain when compared to control group. Our results suggest that short-term exposure to GLY induced alterations in the oxidative stress biomarkers in fish and can be interfering with their survival in natural environment; besides, these findings may be considered of high ecotoxicological relevance.

Silicon is widely available in soil and is known to mitigate both biotic and abiotic stress in plants. Very low doses of silicon are becoming increasingly essential in rice for biofortification and preventing water loss. Soil salinity is a matter of grave concern in various parts of the world, and silicon is a suitable candidate to mitigate salinity-induced stress of important plants in affected areas. The present study investigates the protective capability of exogenously applied silicon in ameliorating NaCl-induced toxicity in two rice (Oryza sativa L.) cultivars, the salt-sensitive MTU 1010, and salt-tolerant Nonabokra. Rice seedlings were treated with three doses of NaCl (25, 50, and 100 mM), initially alone and subsequently in combination with 2 mM sodium silicate (Na₂SiO₃, 9H₂O). After 21 days, these plants were examined to determine levels of reduced glutathione, ascorbic acid, cysteine, and activities of different enzymes involved in the ascorbate-glutathione cycle, viz., glutathione reductase (GR), ascorbate peroxidase (APX), glutathione peroxidase (GPx), and glutathione S-transferase (GST). Though ROS levels increased in both the cultivars with increasing NaCl concentrations, cv. MTU 1010 accumulated comparatively higher amounts. A differential response of NaCl-induced toxicity on the two cultivars was observed with respect to the various enzymatic and non-enzymatic antioxidants. APX and GST activities, as well as, cysteine contents, increased concomitantly with salt concentrations, whereas GR activity declined at increasing salt concentrations, in both cultivars. Activity of GPx increased in cv. Nonabokra but declined in cv. MTU 1010, under similar NaCl concentrations. Reduced glutathione (GSH) contents decreased in both cultivars, whereas ascorbate contents declined in only the sensitive cultivar. Application of silicon, along with NaCl, in the test seedlings of both the cultivars, reduced ROS accumulation and boosted antioxidant defense mechanism, through enhancing ascorbate and GSH levels, and activities of ascorbate-glutathione cycle enzymes as well. However, amelioration of salt-induced damages in the sensitive cv. MTU 1010 was more pronounced upon silicon administration, than the tolerant cv. Nonabokra. Thus, cv. MTU 1010 was found to be more responsive to applied silicon. Hence, this study was instrumental in realizing a successful strategy in silicon-mediated amelioration of salinity stress in plants.

Lead (Pb) is considered one the most hazardous pollutant, and its accumulation in soil and plants is of prime concern. To understand the role of plant hormones in combating heavy metal stress, the present study was planned to assess the interactive effects of 24-epibrassinolide (EBL) (10⁻⁷ M) and salicylic acid (SA) (1 mM) in regulating growth, pigment contents, antioxidative defense response, and gene expression in Brassica juncea L. seedlings exposed to different concentrations of Pb metal (0.25, 0.50, and 0.75 mM). Reduction in root and shoot lengths, chlorophyll and carotenoid content, and non-enzymatic antioxidants like glutathione, ascorbic acid, and tocopherol in response to Pb toxicity was observed. The enzymatic antioxidants such as guaiacol peroxidase (POD), ascorbate peroxidase (APOX), glutathione peroxidase (GR), dehydroascorbate reductase (DHAR), monodehydroascorbate redductase (MDHAR), glutathione-S-transferease (GST), and glutathione peroxidase (GPOX) were lowered in response to Pb treatments. Other antioxidative enzymes including superoxide dismutase (SOD), catalase (CAT), and polyphenol oxidase (PPO) enhanced under metal stress. Co-application of EBL + SA to 0.75 mM Pb-treated seedlings resulted in improvement of root and shoot lengths, chlorophyll, and carotenoid contents. Similarly, glutathione, ascorbic acid, and tocopherol contents were also elevated. Enzymatic antioxidants were also significantly enhanced in response to pre-sowing combined treatment of both hormones. Gene expression analysis suggested elevation in expression of CAT, POD, GR, DHAR, and GST genes by application of EBL. Our results reveal that Pb metal toxicity caused adverse impact on B. juncea L. seedlings, but pre-soaking treatment with EBL and SA individually and in combination help seedlings to counter the ill effects of Pb by improving growth, contents of pigment, and modulation of antioxidative defense system. The combined application of EBL and SA was found to be more effective in ameliorating Pb stress as compared to their individual treatments.

A magnetic adsorbent (MA) was synthesized from wasted iron mud of a groundwater treatment plant using a novel one-step hydrothermal method. The results showed that Fe content of MA was 41.8 wt%, 2.5 times higher than that of iron mud, which was caused by hydrothermal dissolution of non-ferrous impurities under alkaline condition, such as quartz and albite, regardless of addition of ascorbic acid or not. Ferrihydrite was 92.7% in dry iron mud before adding ascorbic acid and gradually decreased to 58.1% by increasing the molar ratio of ascorbic acid to Fe following hydrothermal treatment. The strongest saturation magnetization of 16.29 emu/g was observed in the prepared MA-4 when the ascorbic acid to Fe molar ratio was 1. The highest surface site concentration of 1.31 mmol/g was observed in MA-2 when the ratio was 0.02. The mechanism of hydrothermal conversion of wasted iron mud to MA was reductive dissolution of ferrihydrite to form siderite, which was then reoxidized to maghemite. When 12.5 g/L of MA-2 was applied to treat smelting wastewater, over 99% removal of Cu²⁺, Zn²⁺, Pb²⁺, and Cd²⁺ was achieved. The major mechanisms of Cu²⁺ and Zn²⁺ adsorption by the adsorbent were cationic exchange.

Agricultural utilization of sewage sludge (SS) and fly ash (FA) has become both, a common practice and an alternative disposal method for these wastes all around the world. The present study was conducted to assess the effect and viability of co-application of SS and FA (SLASH) in four mixing ratios denoted as A [4 (SS): 1(FA)], B [4 (SS): 2 (FA)], C [4 (SS): 3 (FA)] and D [4 (SS): 4(FA)] at three application rates viz. 20, 40 and 60% (w/w) with agricultural soil on biochemical, physiological and growth response of Palak (Beta vulgaris L. var. Allgreen H-1), a commonly used green leafy vegetable. SLASH amendment modified the physico-chemical properties of soil and increased the concentration of heavy metals (Cd, Cr, Cu, Fe, Ni, Pb, Zn) in soil and plant parts however, within the Indian permissible limit except for Cr, Cd and Zn in shoot. Experimental results revealed decrease in morphological and growth parameters such as root and shoot length, leaf area, root, shoot biomass etc. Lipid peroxidation, ascorbic acid, proline and protein content increased however, total chlorophyll and carotenoid content decreased indicating towards heavy metal stress induced biochemical and physiological response in Palak plants. Significant increase in yield was seen in some of the treatments viz. three mixing ratios B, C and D, with maximum increment shown by mixture D at 20 and 40% amendment rate. The results of this study suggest that though SLASH amendment for growing Palak improved the physico-chemical properties of soil amended and also the yield of the plants in some treatments, it may not be a good option due to risk of contamination of heavy metals such as Cr, Cd and Zn showing higher accumulation.