Investigation of the combined effects of cadmium chloride, silver nitrate, lead nitrate, methyl jasmonate, and salicylic acid on morphometric and biochemical characteristics of St. John's wort.

Hypericum perforatum L., is a sprawling, leafy herb that grows in open, disturbed areas, known as St. John's wort, has a variety of secondary metabolites that can be used for medicinal and therapeutic purposes. Heavy metals have become the most dangerous pollutants in the environment. The effect of cadmium chloride, lead nitrate, silver nitrate, methyl jasmonate, and salicylic acid was studied on several morphometric and biochemical features of St. John's wort simultaneously using the Taguchi statistical method. The results showed cadmium chloride and lead nitrate reduced the morphometric and biochemical properties of St. John's wort while salicylic acid compensated for the adverse effects of heavy metals. Simultaneously, use of salicylic acid and silver nitrate with cadmium chloride and lead nitrate reduced the toxic effects of these metals on morphometric properties. Methyl jasmonate improved growth characteristics at low levels and inhibited at higher levels. Also, according to the results, salicylic acid could reduce the effects of heavy metals on the biochemical properties, while silver nitrate acts like heavy metals, especially at higher levels. Salicylic acid reduced the harmful effects of these heavy metals and at all levels was able to create a better induction effect on St. John's wort. These elicitors mainly changed the adverse effects of heavy metals by strengthening the pathways of the antioxidant system in St. John's wort. The research assumptions were validated, which suggests that the Taguchi method could be considered in an optimum culture of medicinal plants under different treatments such as heavy metals and elicitors.

Phenanthrene uptake and translocation by Panicum miliaceum L. tissues: an experimental study in an artificial environment.

Polycyclic aromatic hydrocarbons (PAHs), as priority organic pollutants, are capable of accumulation in plants. Phenanthrene (Phe) is one of the most abundant low-molecular-weight PAH in the environment which is commonly used as a model PAH in many phytoremediation studies and as a representative compound for all PAHs group. This paper highlights the uptake, translocation, and accumulation of Phe by growing proso millet (Panicum miliaceum L.) in a pot experiment, subjected to 500, 1000, 1500, and 2000 ppm of Phe treatment after 15 and 30 days. Phe naturally existed in P. miliaceum and its concentration showed a time-dependent reduction in treated plant tissues as well as in perlites. Phe concentration in shoots was higher than in roots. During the aging process, the uptake of Phe was diminished whereas translocation factor (TF) demonstrated an overall increasing trend among treatments. The shoot concentration factor (SCF) values were higher than those of root concentration factor (RCF) on both days 15 and 30 and the highest values for both parameters were achieved in 500 ppm of Phe. Both RCFs and SCFs generally tended to decrease with the increase of perlite Phe concentrations. These results suggested that Phe tended to transfer to the shoots and be metabolized there. The Phe concentration revealed a significant decline in all levels of treatment on both 15 (84 to 96%) and 30 (76 to 94%) days. Therefore, the presence of P. miliaceum was effective in promoting the phytoremediation of Phe polluted perlites.

Effect of TiO2 NPs on the growth, anatomic features and biochemistry parameters of Baby sun rose (Aptenia cordifolia).

Rapid commercialization, industrialization and the use of nanotechnology has led to an increase in the distribution of nanoparticles (NPs) in the environment. The most common metal oxide NPs which is present within products is Titanium dioxide (TiO2). TiO2 NPs have photocatalytic nature and can affect plant growth. The current study investigated the morphological, anatomical and biochemical features of Baby sun rose (Aptenia cordifolia) after exposure to different concentrations of TiO2 nanoparticles (0, 1, 5, 10 and 20 mg L-1). Treatment with TiO2 NPs showed changes in the morphological features and increased photosynthetic pigmentation within the plant. An increase in the level of phenolics (12%) and flavonoid compounds (13%) was observed when plants were treated with moderate levels of TiO2 NPs. A reduction in the diameter of the vascular bundles and increased thickening of the transverse wall were observed in several samples. The number of scattered vascular bundles in the stems increased. The morphological, biochemical, and anatomical responses of Baby sun rose indicates that plants can adapt to environments contaminated with up to 20 mg L-1 TiO2 NPs. The cultivation of Baby sun rose plants in environments polluted with TiO2 NPs is recommended. This study enhances the knowledge of the effect of TiO2 NPs on the growth of Baby sun rose which is an ornamental plant, widely cultivated in different regions of Iran. The results of this study suggest that contaminated environments up to 20 mg L-1 TiO2 NPs can be managed by phytoremediation. Further studies are needed to investigate this plant's tolerance strategies against stress caused by TiO2 NPs and bulk TiO2 as well as the effect of other nanoparticles on plant.

Anatomic features, tolerance index, secondary metabolites and protein content of chickpea (Cicer arietinum) seedlings under cadmium induction and identification of PCS and FC genes.

ABSTRACT: Chickpea (Cicer arietinum) belonging to the Fabaceae family is a major legume crop and is a good source of protein and carbohydrates. Industrialization has resulted in soil contamination with heavy metals such as cadmium. Adsorption of cadmium by plants can lead to reduced yields and heavy metal toxicity. In the current study, changes in the anatomical, morphological features and biochemical properties of the chickpea plant were evaluated. Two indexes DWSTI and PHSTI were determined. Anatomically, there was a change in the number of xylem poles within the root structure which was most significant at treatments of 125 µg cadmium. There was also a noticeable change in leaf pigmentation, the total phenolics and soluble protein in the plant. Cadmium levels were elevated attaining concentrations of 0.21, 0.40 and 0.52 mg per gram dry weight in plants exposed to 62, 125 and 250 µg/g Perlit cadmium after a period of 30 days. A noticeable increase in the level of cadmium in the plant was observed. Two PCS genes, glutathione gamma-glutamylcysteinyltransferase 1 and glutathione gamma-glutamylcysteinyltransferase and four FC genes, 4 proteins and 4 mRNA were detected in chickpeas. Bioinformatics tools were utilized to predict enzyme structure and binding sites. Chickpea may be classified as a cadmium hyperaccumulator and may be considered for use in phytoremediation. This study provides a better understanding with regards to the response of chickpeas to cadmium and the genetic mechanism by which the plant regulates heavy metal toxicity.

Effect of Ag-doping on cytotoxicity of SnO2 nanoparticles in tobacco cell cultures.

SnO2 nanoparticles (NPs) are promising materials for electrochemical, catalytic, and biomedical applications due to their high photosensitivity, suitable stability characteristics, wide band gap energy potential, and low cost. Doping SnO2 NPs with metallic elements such as Ag has been used to improve their efficiency. Despite their commercial importance, the current literature lacks investigations to determine their toxic effects on plant systems. In this study, SnO2 and Ag/SnO2 NPs were synthesized using polymer pyrolysis method and characterized by means of XRD, TEM, SEM, EDX, and DLS techniques. Subsequently, the toxicity of the synthesized NPs on cell viability, cell proliferation, and a number of oxidative stress markers were measured in tobacco cell cultures. SnO2 and Ag/SnO2 NPs were found to be polygonal in shape with the size range of 10-30 nm. Both NPs induced cytotoxicity by reducing the cell viability and cell proliferation in a dose-dependent manner. Furthermore, the generation of H2O2, phenolics, flavonoids, and increased activities of superoxide dismutase (SOD) and peroxidase (POD) were observed. According to the results, Ag-doping played a key role in the induction of toxicity in tobacco cell cultures. The obtained results confirmed that SnO2 and Ag/SnO2 NPs induced cytotoxicity in tobacco cells through oxidative stress.