Unraveling the influence of TiO2 nanoparticles on growth, physiological and phytochemical characteristics of Mentha piperita L. in cadmium-contaminated soil.

Among the metals contaminants, cadmium (Cd) is one of the most toxic elements in cultivated soils, causing loss of yield and productivity in plants. Recently, nanomaterials have been shown to mitigate the negative consequences of environmental stresses in different plants. However, little is known about foliar application of titanium dioxide nanoparticles (TiO2 NPs) to alleviate Cd stress in medicinal plants, and their dual interactions on essential oil production. The objective of this study was to investigate the effects of foliar-applied TiO2 NPs on growth, Cd uptake, chlorophyll fluorescence, photosynthetic pigments, malondialdehyde (MDA) and hydrogen peroxide (H2O2) contents, total phenols, anthocyanins, flavonoids, antioxidant enzymes (SOD, CAT and POD) activity and essential oil content of Mentha piperita L. (peppermint) under Cd stress. For this purpose, plants were grown in Cd-contaminated (0, 20, 40, and 60 mg L-1) soil, and different concentrations of TiO2 NPs (0, 75, and 150 mg L-1) were foliar sprayed at three times after full establishment until the beginning of flowering. Exposure to TiO2 NPs significantly (P < 0.01) increased shoot dry weight (37.8%) and the number of lateral branches (59.4%) and decreased Cd uptake in plant tissues as compared to the control. Application of TiO2 NPs increased the content of plastid pigments, and the ratio Fv/Fm (13.4%) as compared to the control. Additionally, TiO2 NPs reduced the stress markers, MDA and H2O2 contents and enhanced the activity of the phenylalanine ammonia-lyase (PAL) enzyme (60.5%), total phenols (56.1%), anthocyanins (42.6%), flavonoids (25.5%), and essential oil content (52.3%) in Cd-stressed peppermint compared to the control. The results also demonstrated that foliar spray of TiO2 NPs effectively improved the growth and chlorophyll fluorescence parameters and reduced Cd accumulation in peppermint, which was mainly attributed to the reduction of oxidative burst and enhancement of the enzymatic (SOD, CAT, and POD) antioxidant defense system due to the uptake of NPs. The findings provide insights into the regulatory mechanism of TiO2 NPs on peppermint plants growth, physiology and secondary metabolites production in Cd-contaminated soil.

Morphological diversity, phenolic acids, and antioxidant properties in eryngo (Eryngium caucasicum Trautv): Selection of superior populations for agri-food industry.

Eryngo (Eryngium caucasicum Trautv) a widespread species of the Apiaceae reveals high nutritional value and therapeutic properties due to the significant content of biologically active metabolites such as essential oils, phenolic compounds, and flavonoids. The present study was performed to evaluate the morphological and biochemical variability and antioxidant properties of naturally grown populations of eryngo. One-way ANOVA showed significant (p < .01) differences in the majority of parameters measured among the studied populations. The range of fresh weight was from 1.3 to 12.0 g/plant, while dry weight varied from 0.01 to 6.0 g/plant. The highest variation was observed for essential oil yield (CV = 205.32%) followed by essential oil content (CV = 126.23%) and chicoric acid content (CV = 71.18%). Total phenolics content varied from 8.85 to 88.15 mg GAE/g extract. Total flavonoids value ranged from 5.41 to 134.40 mg QE/g extract. Rosmarinic acid and chicoric acid contents varied from 0.118-1.234 and 0.014-0.597 µg/g DW, respectively. DPPH free radical scavenging activity varied from 76.12 to 513.5 µg/mL, while it ranged from 156.7 to 477.1 µg/mL with the ferrous ions (Fe2+) chelating assay. Rosmarinic acid and chicoric acid showed a significant and positive correlation (r 0.01 = 0.81 and r 0.05 = 0.40) with total phenolics, respectively. The Ward dendrogram analysis revealed two different clusters based on the parameters measured, confirming high morpho-phytochemical variability among the individuals and populations. Principal component analysis (PCA) revealed eight PCs which contributed to 99.97% of the overall variance, and leaf length, essential oil content, and antioxidant activity in terms of DPPH and Fe2+ chelating techniques were the most effective attributes for characterizing and selecting the studied population. Based on the traits related to vegetative yield and antioxidant properties, eight individuals from two populations were superior for breeding and/or farming programs.

Natural diversity in fatty acids profiles and antioxidant properties of sumac fruits (Rhus coriaria L.): Selection of preferable populations for food industries.

The current study screened the oil content, fatty acids profile, and antioxidant properties of twelve Iranian sumac fruit accessions. The oil contents were variable among the investigated populations (ranging from 5.15 to 16.70%). Oleic acid (32.3-47.41%), palmitic acid (18.90-36.29%), and linoleic acid (10.31-35.39%) were the predominant fatty acids in the oil samples. According to principal component and cluster analysis, sumac germplasms were categorized into three groups: i.e., group I (five populations rich in linoleic acid), group II (four populations rich in oleic acid), group III (three populations rich in palmitic acid). The highest fruits weight, oil percentage, and linoleic acid content was obtained from Arasbaran population. Arasbaran population possessed the highest ∑PUSFA (i.e, 34.53%) and ∑UNSFA: ∑SFA ratio. Meanwhile, Paveh population possessed the highest antioxidant attributes. Such variabilities provide the possibility of using elite populations containing a high ratio of unsaturated fatty acids and antioxidant compounds in the food industry.