With the regulation of perfluorooctanesulfonate (PFOS), 6:2 chlorinated polyfluoroalkyl ether sulfonate (6:2 Cl-PFESA) has been used as a potential PFOS alternative in electroplating. In this study, the uptake, translocation and phytotoxicity of PFOS and 6:2 Cl-PFESA in mung bean (Vigna radiata (Linn.) Wilczek.) were investigated. The uptake kinetics of PFOS and 6:2 Cl-PFESA fit the Michaelis-Menten equation well, suggesting that the uptake is a carrier-mediated process. The root concentration factor (RCF) of 6:2 Cl-PFESA (34.55 mL g⁻¹ dw) was 1.27 times that of PFOS (27.11 mL g⁻¹ dw), and the translocation factor (TF) of 6:2 Cl-PFESA (0.177) was 1.07 times that of PFOS (0.165). Exposure to 6:2 Cl-PFESA and PFOS both resulted in the inhibition of mung bean seedling development. Treatment with 6:2 Cl-PFESA and PFOS led to the concentration-dependent elevation of malondialdehyde (MDA), carbonyl groups, and phosphorylated histone H2AX (γ-H2AX) levels in mung bean roots. The MDA and carbonyl group contents induced by 6:2 Cl-PFESA were 1.10–1.35 and 1.03–1.14 times, respectively, those of PFOS. The hydroxyl free radical (·OH) levels in mung bean roots after exposure to PFOS and 6:2 Cl-PFESA were elevated significantly, and the ·OH levels induced by 6:2 Cl-PFESA were higher than those induced by PFOS. Hydroxyl free radical levels were positively correlated with the MDA and carbonyl group contents in mung bean roots (p < 0.05). The dynamic changes in some antioxidative enzyme activities in mung bean seedlings were determined, including peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT). The results demonstrated the phytotoxicities of 6:2 Cl-PFESA and PFOS to mung bean in the early developmental stage. 6:2 Cl-PFESA is more harmful to mung beans than PFOS. The production of hydroxyl radical is the mechanism that causes the toxicity of PFOS and 6:2 Cl-PFESA toward plants.

Rhizosphere acidification in leguminous plants can release P from the dissolution of phosphate compounds which can reduce Pb bioavailability to them via the formation of insoluble Pb compounds in their rhizosphere. A soil polluted from Pb-acid batteries effluent (SPBE), having total Pb = 639 mg kg⁻¹, was amended with six different rates (0, 0.5, 1, 2, 4 and 6%) of oxalic acid-activated phosphate rock (OAPR) and their effects on pH, available P and bioavailable Pb concentrations in the rhizosphere and bulk soils of mung bean plant were evaluated. Furthermore, the effects of these variant OAPR rates on Pb concentrations in plant parts, bioaccumulation factor (BAF) and translocation factor (TF) for Pb in grain and traits like productivity, the activities of antioxidant enzymes, and grain biochemistry were investigated. Results revealed that increasing rates of OAPR significantly increased pH values and available P while decreased bioavailable Pb concentrations in the rhizosphere over control. The highest dissolution of P in the rhizosphere was with 4 and 6% OAPR rates. As a result, the formation of insoluble Pb compounds affected on reduced Pb concentrations in shoots, roots, and grain in addition to lower grain BAF and TF values for Pb over control. Likewise, the highest plant productivity, improved grain biochemistry, high Ca and Mg concentrations, least oxidative stress, and enhanced soil alkaline phosphatase activity were found with 4 and 6% OAPR rates. The OAPR 4% rate is suggested for reducing grain Pb concentration, cell oxidative injury, and improving grain biochemistry in mung bean.

The growth, development and functioning of legumes are often significantly affected by exposure to tropospheric ozone (O3) pollution. However, surprisingly little is known about how leguminous Nitrogen (N) fixation responds to ozone, with a scarcity of studies addressing this question in detail. In the last decade, ozone impacts on N-fixation in soybean, cowpea, mung bean, peanut and clover have been shown for concentrations which are now commonly recorded in ambient air or are likely to occur in the near future. We provide a synthesis of the existing literature addressing this issue, and also explore the effects that may occur on an agroecosystem scale by predicting reductions in Trifolium (clovers) root nodule biomass in United Kingdom (UK) pasture based on ozone concentration data for a “high” (2006) and “average” ozone year (2008). Median 8% and 5% reductions in clover root nodule biomass in pasture across the UK were predicted for 2006 and 2008 respectively. Seasonal exposure to elevated ozone, or short-term acute concentrations >100 ppb, are sufficient to reduce N-fixation and/or impact nodulation, in a range of globally-important legumes. However, an increasing global burden of CO2, the use of artificial fertiliser, and reactive N-pollution may partially mitigate impacts of ozone on N-fixation.

Increasing anthropogenic and biogenic emissions of precursor compounds have led to high tropospheric ozone concentrations in India particularly in Indo-Gangetic Plains, which is the most fertile and cultivated area of this rapidly developing country. Current ozone risk models, based on European and North American data, provide inaccurate estimations for crop losses in India. During the past decade, several ozone experiments have been conducted with the most important Indian crop species (e.g. wheat, rice, mustard, mung bean). Experimental work started in natural field conditions around Varanasi area in early 2000's, and the use of open top chambers and EDU (ethylene diurea) applications has now facilitated more advanced studies e.g. for intra-species sensitivity screening and mechanisms of tolerance. In this review, we identify and discuss the most important gaps of knowledge and future needs of action, e.g. more systematic nationwide monitoring for precursor and ozone formation over Indian region.

Cadmium (Cd) pollution has attracted global concern. In the present study, the biochemical mechanisms underlying the amelioration of 24-epibrassinolide (eBL) and abscisic acid (ABA) on Cd tolerance of roots, stems, and leaves in mung bean seedlings were comparatively analyzed. Foliar application of eBL markedly ameliorated the growth of mung bean seedling exposed to 100 μM Cd. eBL alone had no significant effects on the activities of antioxidative enzymes and the contents of glutathione (GSH) and polyphenols in the three organs whereas significantly increased the root, stem, and leaf proline contents on average by 54.9%, 39.9%, and 94.4%, respectively, and leaf malondialdehyde (MDA) content on average by 69.0% compared with the controls. When the plants were exposed to Cd, eBL significantly reversed the Cd-increased root ascorbate peroxidase (APX) and superoxide dismutase (SOD) activities, root polyphenol, proline, and GSH levels, leaf chlorophyll contents, and MDA levels in the three organs. eBL significantly restored the Cd-decreased leaf catalase (CAT) activity and leaf polyphenol levels. These results indicated that eBL played roles in maintaining cellular redox homeostasis and evidently alleviated Cd-caused membrane lipid peroxidation via controlling the activity of antioxidative systems. eBL mediated the differential responses of cellular biochemical processes in the three organs to Cd exposure. Furthermore, a comparative analysis revealed that, under Cd stress, the effects of eBL on the biochemical processes were very similar to those of ABA, suggesting that ABA and eBL improve plant Cd tolerance via some common downstream pathways.

Biochar produced from agricultural residues through pyrolysis has the characteristics of large specific surface area and porous structure and thus can be used as an adsorbent for various contaminants. In this study, five types of agricultural residues, peanut shells (PS), mung bean shells (MBS), rice husk (RH), corn cob (CC), and cotton stalks (CS), were selected as feedstocks to prepare biochars. Magnesium chloride (MgCl₂; 5 mol L⁻¹ m) solution was used as a modifier to prepare pre-modified and post-modified biochar adsorbents. The modified biochars were used in adsorption experiment to test their sorption ability to phosphate from aqueous solution. Model simulations and analysis were used to determine phosphorus removal mechanisms. Experimental results showed that the phosphate removal efficiency of the pre-modified cotton stalk paralyzed at 600 °C (Pre-CS600) was the best with adsorption capacity of 129.9 mg g⁻¹. The results also showed that the adsorption capacity of the biochar pre-modified by MgCl₂ was much better than that of unmodified and post-modified ones, suggesting the pre-modification method can be used to prepare modified biochars for the removal of phosphorus from aqueous solution.

Experiments were conducted to determine how exogenous abscisic acid (ABA) mediates the tolerance of plants to cadmium (Cd) exposure. Cd stress strongly reduced all the growth parameters of mung bean seedlings. Cd significantly increased ascorbate peroxidase (APX) and catalase (CAT) activities in roots and stems, and peroxidase (POD) activities in roots, stems, and leaves of mung bean seedlings. Cd caused remarkable increases in the levels of leaf chlorophyll and carotenoid, root polyphenols, and malondialdehyde (MDA) and proline in the three organs. However, Cd greatly decreased leaf CAT activity, root and leaf ascorbic acid (AsA) levels, and stem and leaf polyphenol levels. Foliar application of ABA partially alleviated Cd toxicity on the seedlings. ABA could restore most of the changed biochemical parameters caused by Cd, suggesting that ABA played roles in the protection of membrane lipid peroxidation and the modulation of antioxidative defense systems in response to Cd stress. Our results also implied the differential physiological and biochemical responsive patterns of roots, stems, and leaves to Cd and ABA in mung bean seedlings. The great changes in many biochemical parameters in roots suggested that roots were the first to be affected by Cd and play pivotal roles in response to Cd, especially in chelating Cd and reducing Cd absorption.

Contamination of soils with heavy metals (HMs) caused serious problems because plants tend to absorb HMs from the soil. In view of HM hazards to plants as well as agro-ecosystems, we executed this study to assess metal toxicity to mung bean (Vigna radiata) plants cultivated in soil with six treatment levels of cadmium (Cd) and nickel (Ni) and to find metal tolerant variety, i.e., M-93 (V₁) and M-1(V₂) with multifarious plant biochemical and physiological attributes. Increasing doses of Cd and Ni inhibited plant growth and photosynthesis and both varieties showed highly significant differences in the morpho-physiological attributes. V₂ showed sensitivity to Cd and Ni treatments alone or in combination. Tolerance indices for attributes presented a declined growth of Vigna plants under HM stress accompanied by highly significant suppression in gas exchange characteristics. Of single element applications, the adverse effects on mung bean were more pronounced in Cd treatments. V₁ showed much reduction in photosynthesis attributes except sub-stomatal CO₂ concentration in all treatments compared to V₂. The yield attributes, i.e., seed yield/plant and 100-seed weight, were progressively reduced in T₅ for both varieties. In combination, we have observed increased mobility of Cd and Ni in both varieties. The results showed that water use efficiency (WUE) generally increased in all the treatments for both varieties compared to control. V₂ exhibited less soluble sugars and free amino acids compared to V₁ in all the treatments. Similarly, we recorded an enhanced total free amino acid contents in both varieties among all the metal treatments against control plants. We conclude that combinatorial treatment proved much lethal for Vigna plants, but V₁ performed better than V₂ in counteracting the adverse effects of Cd and Ni.

The present work provides an insight into the development of biochemical adaptations in mung beans against ozone (O₃) toxicity. The study aims to explore the O₃ stress tolerance potential of mung bean genotypes under exogenous application of growth regulators. The seeds of twelve mung bean genotypes were grown in plastic pots under controlled conditions in the glasshouse. Six treatments, control (ambient ozone level 40–45 ppb), ambient O₃ with ascorbic acid, ambient ozone with silicic acid, elevated ozone (120 ppb), elevated O₃ with ascorbic acid (10 mM), and elevated ozone with silicic acid (0.1 mM) were applied. The O₃ fumigation was carried out using an O₃ generator. The results revealed that ascorbic acid and silicic acid application decreased the number of plants with foliar O₃ injury symptoms in different degrees, i.e., zero, first, second, third, and fourth degrees; whereas 0–4 degree symptoms represent, no symptoms, symptoms occupying < 1/4, 1/4–1/2, 1/2–3/4, and > 3/4 of the total foliage area, respectively. Application of ascorbic acid and silicic acid also prevented the plants from the negative effects of O₃ in terms of fresh as well as dry matter production, leaf chlorophyll, carotenoids, soluble proteins and ascorbic acid, proline, and malondialdehyde (MDA) contents. Overall, silicic acid application proved more effective in reducing the negative effects of O₃ on mung bean genotypes as compared to that of the ascorbic acid. Three mung bean genotypes (NM 20–21, NM-2006, and NM-2016) were identified to have a better adaptive mechanism for O₃ toxicity tolerance and may be good candidates for future variety development programs.

Petroleum hydrocarbon, a complex mixture including aliphatic and aromatic hydrocarbons, is known to have negative effects on the environment. We determined the effectiveness of persulfate (PS) (5% w/w) activated using 1% (w/w) of various types of soil minerals, goethite (α-FeOOH), hematite (Fe₂O₃), magnetite (Fe₃O₄), maghemite (γ- Fe₂O₃), manganese oxide (MnO₂), and zeolite (clinoptilolite) to treat petroleum hydrocarbon-contaminated soil. Total petroleum hydrocarbon (TPH) was 4200 ± 124 mg kg⁻¹. The TPH removal efficiency was in the order: Fe₃O₄ > MnO₂ > γ-Fe₂O₃ > Fe₂O₃ > α-FeOOH > clinoptilolite. When the PS dosage and the moisture content of the soil increased, the degradation rate (k ₒbₛ) of TPH removal increased; on the other hand, lowering the pH increased the k ₒbₛ of TPH removal. The PS oxidation of TPH was optimized using response surface methodology (RSM). The interactive effects of three factors, namely, persulfate dosage (X ₁), pH (X ₂), and soil moisture content (X ₃), were investigated. The optimum removal of TPH by PS oxidation activated using 1% (w/w) magnetite was obtained at 5.5% (w/w) PS and 85% (w/w) moisture content at an initial pH of 4.5. However, the soil treated by PS showed a negative effect on soil health. The germination of mung bean (Vigna radiata (L.) R. Wilczek) and the CO₂ release for the treated soil were low, indicating that toxicity had occurred in the treated soil. To restore the treated soil, adding a soil amendment, like CaCO₃, fly ash, or crop residue, was able to improve plant growth and soil microbial activity.