Dietary arsenic (As) intake from food is of great concern, and developing a reliable model capable of predicting As concentrations in plant edible parts is desirable. In this study, pot experiments were performed with 16 Chinese upland soils spiked with arsenate [As(V)] to develop a predictive model for As concentrations in pepper fruits (Capsicum annum L.). Our results showed that after three months’ aging, concentrations of bioavailable As (extracted by 0.05 M NH₄H₂PO₄) in various soils varied widely, depending on soil total As concentrations and soil properties such as soil pH and amorphous iron (Fe) contents. Furthermore, both the bioconcentration factor (BCF, denoted as the ratio of fruit As to soil As) and total As concentrations in pepper fruits were largely determined by concentrations of bioavailable As, which explained 27% and 69% variations in the BCF and fruit As concentrations, respectively. Apart from bioavailable As, soil pH and Fe contents were another two important factors influencing As accumulation in pepper fruits. Taking the three factors into account, concentrations of fruit As can be well predicted using a stepwise multiple linear regression (SMLR) analysis (R² = 0.80, RMSE = 0.17). Arsenic species in soils and edible parts were also analyzed. Although As(V) predominated in soils (>96%), As in pepper fruits presented as As(V) (46%) and arsenite [As(III)] (39%) with small amount of methylated As (<15%). Aggregated boosted tree (ABT) analysis revealed that inorganic As concentrations in pepper fruits were determined by concentrations of bioavailable As, phosphorus (P) and Fe in soils. In contrast to inorganic As, methylated As concentrations were not correlated with those factors in soils. Taken together, this study established an empirical model for predicting As concentrations in pepper fruits. The predictive model can be used for establishing the As threshold in fruit vegetable farming soils.

Predicting the translocation of organic contaminants to plants is crucial to ensure the quality of agricultural goods and assess the risk of human exposure through the food web. In this study, the performance of a modified plant uptake model was evaluated considering a number of chemicals, such as polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs) and polybrominated diphenyl ethers (PBDEs), with a range of physicochemical properties; different plant species (Ipomoea aquatica Forsk (swamp morning glory), Chrysanthemum coronarium L. (crown daisy), Zea mays L. (corn), Brassica rapa pekinensis (Chinese cabbage), Cucurbita moschata (pumpkin), Raphanus sativus L. (radish), Spinacia oleracea L. (spinach) and Capsicum annuum L. (pepper)); and different types of soil (paddy soil, laterite soil and black soil). The biases of predictions from a previously used partition-limited model were −76.4% to −99.9% relative to the measured concentrations. An overall transmission factor (αtf=0.39), calculated from a linear regression of the measured bioavailable fraction (Cbᵢₒ) and the total concentration in plants, was considered a crucial modification and was included in the modified model. Cbᵢₒ was found to better represent the chemical content available in soil for root uptake. The results from this study improve the accuracy of predictions for vegetation-uptake assessments by modifying the partition-limited model and then validating the modified model using comparisons between predicted data and measured values. The accuracy of the concentrations of organic contaminants in plants improved: when using the modified model, 89.5% of the predictions were within 40% of the actual value. The average bias was limited to 1.5%–30.5%. The model showed great potential to predict plant uptake using the bioavailable fraction concentration in soil.

The promising response of chromium-stressed (Cr(VI)–S) plants to hydrogen sulphide (H₂S) has been observed, but the participation of nitric oxide (NO) synthesis in H₂S-induced Cr(VI)–S tolerance in plants remains to be elucidated. It was aimed to assess the participation of NO in H₂S-mediated Cr(VI)–S tolerance by modulating subcellular distribution of Cr and the ascorbate-glutathione (AsA-GSH) cycle in the pepper seedlings. Two weeks following germination, plants were exposed to control (no Cr) or Cr(VI)–S (50 μM K₂Cr₂O₇) for further two weeks. The Cr(VI)–S-plants grown in nutrient solution were supplied with 200 μM sodium hydrosulphide (NaHS, donor of H₂S), or NaHS plus 100 μM sodium nitroprusside (SNP, a donor of NO). Chromium stress suppressed plant growth and leaf water status, while elevated proline content, oxidative stress, and the activities of AsA-GSH related enzymes, as well as endogenous H₂S and NO contents. The supplementation of NaHS increased Cr accumulation at root cell walls and vacuoles of leaves as soluble fraction to reduce its toxicity. Furthermore it limited oxidative stress, improved plant growth, modulated leaf water status, and the AsA-GSH cycle-associated enzymes’ activities, as well as it further improved H₂S and NO contents. The positive effect of NaHS was found to be augmented on those parameters in the CrS-plants by the SNP supplementation. However, 0.1 mM cPTIO, the scavenger of NO, inverted the prominent effect of NaHS by decreasing NO content. The supplementation of SNP along with NaHS + cPTIO reinstalled the positive effect of NaHS by restoring NO content, which suggested that NO might have a potential role in H₂S-induced tolerance to Cr(VI)–S in pepper plants by stepping up the AsA-GSH cycle.

Large areas of soil are boron (B) deficient and contaminated with cadmium (Cd) in southern China. The aim of this study was to select the optimal B supply level and elucidate the underlying physiological and biochemical mechanisms to understand how B reduces Cd influx into root cells of hot pepper (Capsicum annuum). An experiment was conducted to investigate the changes in Cd accumulation with B supply. Hot pepper seedlings were grown in two nutrient solutions containing 0.05- and 0.2-mg Cd L⁻¹ and supplied with six different B concentrations for 2 weeks. The other experiment was conducted to determine the Cd²⁺ flux into cells, cell wall components, antioxidative ability, and plasmalemma permeability of root tips of hot pepper exposed to 0.1-mg Cd L⁻¹ in the presence and absence of B. The results showed that the optimal B concentration to promote plant growth and reduce Cd accumulation was 0.25 mg L⁻¹. Moreover, B application significantly decreased Cd²⁺ influx into cells, increased the contents of lignin and pectin, enhanced the activities of antioxidant enzymes, reduced the production of reactive oxygen species, and decreased membrane peroxidation and permeability. Overall, boron in moderation can promote plant growth, maintain the normal structures and functions of the cell wall and membrane, and thus decrease Cd²⁺ influx into root cells and subsequently Cd translocation to shoots. Consequently, B is a reliable inhibitor of Cd uptake, and the functional and structural integrity of cell walls and membranes may have some relevance to reduced Cd uptake after B application.

Nowadays, the use of different nanoscale structures has been introduced to a large number of research areas. One of these is the treatment and remediation of water through photocatalytic processes, seeking to reuse wastewater for agriculture. In this paper, Lactuca sativa, Coriandrum sativum, and Capsicum annuum were used as crop models to observe the effects in plant growth and the secondary metabolism of different water qualities and types used in the watering process. Initial results show that the photocatalytic process’s water maintains a pH and ion concentration within the allowed limits, significantly reducing the number of bacteria. Along the growth process, an influence on germination times, appearance of true leaves, maturation, and fruit production depending on the type of water used is observed, obtaining the best results in both growth times and quantity of fruits, for the 50% and 70% disinfected water/tap water (DW/TAW) study groups. Secondary metabolites, such as phenols, flavonoids, and antioxidant activity, were studied to evaluate changes in the vegetables’ composition, showing increased concentration for the disinfected water groups in most specimens. Additionally, no traces of metals and microorganisms were detected, concluding that the crops are viable to be consumed by human beings.

Samples of soil and food plants were collected from wastewater-irrigated and control fields in the vicinity of Gaziantep, in southeast Turkey. The samples were analyzed for concentrations of several macro and trace elements to evaluate spatial differences and bioaccumulation. Emphasis was placed on redoximorphic metal (Mn/Fe) interactions. The plants and tissues that studied were corn (Zea mays) seeds, mint (Mentha) leaves, the vegetables eggplant (Solanum melongena L.) and pepper (Capsicum annuum L.), and tomato (Solanum lycopersicum L.) fruits. Concentrations of Mn and Fe in corn were generally lower than in the other food plants, while concentrations of Mn, Fe, and several elements in mint were higher in other plants. Except for mint, the Mn deficiencies in the various plant samples can be attributed to low Mn soil concentrations and the chemical and physical characteristics of the soil. Mn concentrations in both wastewater-irrigated soils and control soils were lower than what has been reported as an average for the Earth’s crust (crustal average). There was considerable variability in the concentrations of Fe, with mint having the highest concentration (650 mg/kg) and corn the lowest (20 mg/kg). Significant positive relationships (coefficient of determination (R²) >0.50) were calculated between Mn and Fe in corn (R² = 0.83). The R²for tomato was 0.43, but all other relationships were much poorer for all other species. Several elements (trace and macro) demonstrated positive relationships with Mn or Fe, although there was little across-species consistency. For example, the R²values for both Mn and Fe correlated with Zn, P, and Mg were all >0.80 for Z. mays, but were all <0.10 for Mentha. The response of the members of the Solanaceae family (eggplant, pepper, and tomato) to the presence of Mn, Fe, and other soil constituents was similar in many respects, showing differences from Z. mays and, in particular, Mentha. Similarities among related plants are not surprising and would be expected given similar physiologies and metabolic pathways. Higher uptake of certain metals may be associated with the dominant form of the element in the soil matrix. The uptake of chemicals to plant tissues is influenced by the chemical and physical characteristics of the soil and species-specific factors.

In recent years, air pollution has increased with rapid urbanization, industrial activities, and traffic density, especially in developing countries. The consumption of the vegetables grown in city centers with high levels of traffic-related pollution poses a major risk to human health due to the heavy metals contained by these plants. Heavy metals have toxic and carcinogenic effects on the human body even when consumed in low concentrations. The aim of this study is to determine the change in the accumulation of Cr, Co, and Ni elements in cucumber (Cucumis sativus L.), tomato (Solanum lycopersicum L.), and pepper (Capsicum annuum L.) vegetables grown in heavy, light, and almost no traffic areas in Ankara province based on plant species, plant organs, and washing condition. The change of Co, Cr, Ni concentrations based on traffic density showed differences depending on the factors studied. It was remarkable that the Cr and Co concentrations in the washed fruits increased depending on the traffic density in general. This increase means that Cr and Co penetrate into the fruits. These results indicate how harmful the consumption of products grown near areas with heavy traffic and industrial facilities can be since heavy metals are found in high levels in these areas.

This study aimed to assess the effects of thallium (Tl) on the leaf concentration of macronutrients (N, P, K, Ca, Mg, and S) and the stoichiometric relationships of P, K, Ca, Mg, and S with N in three varieties of chili pepper (Capsicum annuum): Jalapeño, Poblano, and Serrano. Sixty-day-old seedlings of the three varieties were treated with Tl, in doses of 0, 5.5, and 11 nM in the nutrient solution. After 80 days of exposure to Tl treatments, the nutrient concentration in leaf tissue was determined. With the data obtained, an analysis of variance and comparison of means with Tukey’s test ([Formula: see text]) were carried out, and through a meta-analysis, the size and direction of the effect of the evaluated Tl doses were determined, in the leaf concentrations of macronutrients. The 5.5 and 11 nM Tl doses increased the leaf concentration of P in Serrano and that of N in Poblano, respectively. Applying 5.5 nM Tl significantly reduced the leaf concentration of K in Jalapeño and Serrano, that of Ca in Poblano, and that of Mg in Serrano. In Jalapeño, both Tl doses tested reduced the leaf Ca concentration. Low Tl doses (5.5 nM) caused significant and positive effects on the leaf K concentration in all three varieties. High Tl doses (11 nM) caused significant negative effects on the leaf concentration of Mg. In the three varieties evaluated, the addition of Tl increased the leaf N:K ratio, that of N:Mg in Poblano and Serrano, the N:Mg ratio in Jalapeño, the P:K ratio in Serrano, and the N:Ca ratio in Jalapeño and Poblano. There was no effect of Tl on shoot dry biomass in any variety evaluated. In Tl-treated plants, foliar concentration of this element varied from12.0 to 26.6 mg kg⁻¹ on a dry basis. The sum of principal component 1 and principal component 2 represented 80.8, 72.3, and 79.6% of the total variance of macronutrient concentration in leaves of the Jalapeño, Poblano, and Serrano varieties, respectively. We conclude that Tl had differential effects on the nutrient status among varieties of chili pepper, with Jalapeño being the most affected and Poblano the least.

The effectiveness of adsorbent agent from agricultural wastes and biomass to remove dye from aqueous solution was investigated. In this study, solution of methylene blue (MB) and two adsorbents, bark of cengal tree (Neobalanocarpus hepmii) and seed of red chili (Capsicum annuum), were tested. Experiments were performed with testing MB solution at 3-h interval and also testing with different quantities of adsorbent. In addition, the further study on characterization of adsorbent by Field Emission Scanning Electron Microscopy (FESEM) and Fourier Transform Infrared Spectroscopy (FTIR) was conducted in order to elucidate the properties and surface structure of the adsorbents. Analysis from UV-Vis spectroscopy showed that both adsorbents remove MB dye effectively and according to FESEM analysis due to the structure of the adsorbent were perforated and consist of polymer components. On the other hand, in FTIR perspective, the adsorption was successful because of the presence of carboxyl and carbonyl groups from both adsorbent that helps enhanced the process of adsorption.