Foliar-applied silicate potassium modulates growth, phytochemical, and physiological traits in Cichorium intybus L. under salinity stress.

One of the major problems endangering plant growth and productivity worldwide is salt stress. This study aimed to assess the effects of potassium silicate (K2O3Si) on the physical, biochemical, and morphological characteristics of chicory (Cichorium intybus L.) under various levels of salinity stress. The plants were treated with K2O3Si at concentrations of 0, 1, 2, and 3 mM and cultivated under different salt stress conditions (0, 80, 160, and 240 mM NaCl). The findings revealed that salt stress led to decreased root and shoot dry weights, Fv/Fm ratio, chlorophyll a, b, and total chlorophyll, as well as inulin contents. However, foliar exposure to K2O3Si at all salinity levels resulted in improvements in the measured traits. As salinity levels increased, there was a corresponding increase in the accumulation of sodium ions (Na+) and a sharp reduction in potassium ions (K +) in the shoot. Nonetheless, treatment with K2O3Si caused a decrease in Na + accumulation and an improvement in K+ content under all salinity levels. Carotenoid content increased under 80 mM salinity stress, but decreased with higher salinity levels. Application of K2O3Si at all levels resulted in increased carotenoid content under salinity stress conditions. The content of MDA increased significantly with increasing salinity stress, particularly at 240 mM. However, foliar spraying with K2O3Si significantly decreased MDA content at all salinity levels. Salinity stress up to 160 mM increased the total phenol, flavonoid, and anthocyanin contents, while 240 mM NaCl decreased the biosynthesis of phytochemicals. Additionally, the use of K2O3Si increased the content of total phenol, flavonoid, and anthocyanin at all salt levels. Foliar application of K2O3Si increased the tolerance of chicory plants to salinity stress by reducing MDA and increasing phenolic compounds and potassium content. These results suggest that exogenous K2O3Si can be a practical strategy to improve the growth and yield of chicory plants exposed to saline environments.

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.

Nano-silicone and Ascophyllum nodosum-based biostimulant down-regulates the negative effect of in vitro induced-salinity in Rosa damascena.

BACKGROUND: Rosa damascena is extensively cultivated in various regions of Iran due to its aesthetic attributes, medicinal qualities, and essential oil production. This study investigated the efficacy of Ascophyllum nodosum extract (AnE) at concentrations of 0, 2, and 3 g L- 1 and Nano-silicon (nSiO2) at concentrations of 0, 50, and 100 mg L- 1 in ameliorating the impact of salinity on two genotypes of Damask rose ('Chaharfasl' and 'Kashan') under in vitro culture conditions. Additionally, various physio-chemical characteristics of R. damascena explants were assessed. RESULTS: The findings revealed that exposure to 100 mM NaCl resulted in a substantial reduction in the Relative Water Content (RWC), Membrane Stability Index (MSI), leaf pigments (Chlorophyll b, Chlorophyll a, total Chlorophyll, and carotenoids), chlorophyll fluorescence parameters, and protein content in both genotypes when compared to control conditions. Salinity induced a significant increase in the parameter F0 and a decrease in the parameter Fv/Fm compared to the control conditions in both genotypes. Nonetheless, the genotype Kashan treated with 3 g L- 1 AnE + 100 mg L- 1 nSiO2 exhibited the maximum Fm value under control conditions, with a significant difference compared to other treatments. Furthermore, salinity caused a considerable reduction in Fm in both 'Kashan' and 'Chaharfasl' by 22% and 17%, respectively, when compared to the control condition. 'Kashan' displayed the maximum Fv/Fm compared to the other genotype. The maximum levels of Malondialdehyde (MAD) and hydrogen peroxide (H2O2) were also observed in explants affected by salinity. The combination of 3 g L- 1 AnE + 100 mg L- 1 nSiO2, followed by 2 g L- 1 AnE + 100 mg L- 1 nSiO2, exhibited substantial positive effects. Salinity also led to an increase in proline content and the activity of peroxidase (POD), superoxide dismutase (SOD), guaiacol peroxidase (GPX), and catalase (CAT) in both genotypes. The activity of these enzymes was further enhanced when AnE was applied at concentrations of 2 and 3 g L- 1 in combination with 100 mg L- 1 nSiO2. CONCLUSIONS: The 'Kashan' genotype displayed greater tolerance to salinity by enhancing water balance, maintaining membrane integrity, and augmenting the activity of antioxidant enzymes compared to 'Chaharfasl'. The utilization of nSiO2 and AnE biostimulants demonstrated potential benefits for R. damascena, both under salinity and control conditions. These findings hold substantial importance for researchers, policymakers, and farmers, offering valuable insights into the development of salinity-tolerant crop varieties.

In vitro assessment of physiological traits and ROS detoxification pathways involved in tolerance of Damask rose genotypes under salt stress.

Rosa damascena is one of the most important medicinal and ornamental plants in Iran which is tolerant of salinity to some extent. However, the selection of genotypes that are more tolerant to salinity will influence on Damask cultivation in salt stress-affected regions. For this purpose, a factorial experiment in a completely randomized design with three replicates was performed under in vitro conditions on four Damask rose genotypes (Atashi, Bi-Khar, Chahar-Fasl and Kashan) at 5 concentrations of NaCl (0, 25, 50, 75, and 100 mM), and the physico-chemical traits were measured 14 and 28 days after treatment.The results showed that Atashi genotype with high levels of Chl a, Chl b, total Chl content, carotenoids, relative leaf water content, proline, total soluble protein, TPC, TFC, TAA, and the highest increase in the activity of antioxidant enzymes such as GPX, APX, CAT, SOD, and POD as well as the lowest amount of hydrogen peroxide showed a better protection mechanism against oxidative damage than the other three genotypes (Bi-Khar, Chahar-Fasl and Kashan) in the 14th and 28th days by maintaining the constructive and induced activities of antioxidant enzymes, it was shown that Bi-Khar genotype had moderate tolerance and Kashan and Chahar-Fasl genotypes had low tolerance to salinity stress. In vitro selection methods can be used effectively for salt tolerant screening of Damask rose genotypes, although the same experiment should be conducted in open filed cultures to verify the in vitro experimental results.

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.

Zinc Application Mitigates Copper Toxicity by Regulating Cu Uptake, Activity of Antioxidant Enzymes, and Improving Physiological Characteristics in Summer Squash.

Zinc (Zn) and copper (Cu) are essential micronutrients for the plant's growth, development, and metabolism, but in high concentrations, the elements disrupt normal metabolic processes. The present study investigated the effects of different concentrations (added to a Hogland-based solution) of zinc (control, 5, 10 mg L-1 ZnSO4) and copper (control, 0.1, 0.2 mg L-1 CuSO4) on the growth characteristics and biochemical indices of summer squash (Cucurbita pepo L.). Compared with control, a single application of Cu or Zn at both concentrations significantly declined fruit yield, growth traits, pigments content, and high content of these minerals and values of stress-related indices. Increased Cu concentration in the nutritional solutions reduced the activity of ascorbate peroxidase (APX) and guaiacol peroxidase (GPX). Copper at high concentrations intensified ROS production, aggravated oxidative stresses, and decreased the plant yield and productivity. Nonetheless, combining Cu and Zn could alleviate stress intensity by boosting antioxidant enzymes, redox regulation, and a resultant diminishment in the content of H2O2, proline, malondialdehyde, and minerals. The obtained results corroborate that the co-application of zinc in Cu-contaminated areas can improve the plant's economic yield and physiological parameters by hindering copper toxicity and enhancing the photosynthetic capacity.

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.

Funneliformis mosseae inoculation under water deficit stress improves the yield and phytochemical characteristics of thyme in intercropping with soybean.

Intercropping of medicinal plants/legumes along with bio-fertilizer application is a relatively new sustainable practice for improving the yield and secondary metabolites production. Here, a 2-years field experiment was performed to evaluate the effects of water deficit stress and arbuscular mycorrhizal fungi (AMF) application (as bio-fertilizer) on nutrients concentration, dry matter yield, essential oil quantity and quality of thyme in intercropping with soybean. Three irrigation levels, including (i) irrigation after depletion of 20% (I20) as non-stressed, 50% (I50) as moderate water deficit and 80% (I80) available water as severe water deficit were applied as the main factor. The sub-factor was represented by different cropping patterns including thyme sole culture, replacement intercrop ratio of 50:50 and 66:34 (soybean: thyme) and the third factor was non-usage (control) and usage of AMF. According to our results, the thyme dry yield under moderate and severe water deficit stress decreased by 35 and 44% in the first year, and by 27 and 40% in the second year compared with non-stressed (I20) plants, respectively. Also, the macro- and micro-nutrients of thyme leaves increased significantly in intercropping patterns after application of AMF. The maximum essential oil percentage of thyme was achieved in 50:50 intercropping ratio treated with AMF. Under moderate and severe water deficits, the major constituents of thyme essential oil including thymol, p-cymene and γ-terpinene were increased in intercropping patterns treated with AMF. Generally, AMF application in intercropping ratio of 50:50 may be proposed to farmers as an eco-friendly approach to achieve desirable essential oil quality and quantity in thyme under water deficit stress conditions.

Deciphering morpho-physiological and phytochemical attributes of Tanacetum parthenium L. plants exposed to C60 fullerene and salicylic acid.

This study was aimed to evaluate the effects of C60 fullerene concentrations (0, 125, 250, 500 and 1000 mg/L) and salicylic acid (0 and 0.2 mM) on growth and phytochemical accumulation of two feverfew genotypes (Pharmasaat and Jelitto) in a factorial experiment based on completely randomized design with three replications. According to the ANOVA, triple interaction of treatments were significant on morphological and phytochmical traits, however, the main effect of treatments only affected physiological attributes. Application of salicylic acid differentially influenced the effects of various concentrations of C60 fullerene on growth traits of both genotypes. In Pharmasaat, foliar application of salicylic acid increased growth traits of plants exposed to C60 fullerene at all concentrations, however, it improved the growth of Jelitto at higher levels of fullerene. The maximum increase of flower + leaf dry weight was recorded at 1000 mg/L C60 fullerene in combination with salicylic acid compared to control for Jelitto. In Pharmasaat, the parthenolide content significantly increased following increase of C60 fullerene up to 250 mg/L with salicylic acid, but a rapid decrease followed at 500-1000 mg/L. SEM images showed a wider deposition (many spheres with different sizes) of C60 fullerene on leaf tissue of Pharmasaat exposed to high concentration, involving changes in trichome density and tissue rupture. The essential oil content was not significantly increased upon experimental treatments compared to control. Based on hierarchical cluster analysis, C60 fullerene and salicylic acid treatments caused to a co-induction of ion leakage, chlorophyll a, essential oil and parthenoloide in Pharmasaat.