Quantum dots are promising nano-elicitors that modulate plant physiology via redox signaling and metabolic adjustments. This study explores their effects on medicinal plant tissue cultures, specifically focusing on Calotropis procera. Therefore, this study aimed to establish an optimized protocol for callus induction in C. procera and evaluate the dose-dependent physiological and biochemical responses of callus to copper quantum dots (Cu-QDs). Callus cultures were successfully initiated from leaf explants on MS medium supplemented with naphthalene acetic acid (0.5 mg L− 1), kinetin (1.0 mg L− 1), and 2,4-dichlorophenoxyacetic acid (0.2 mg L− 1), producing semi-compact, friable calli with a high proliferation capacity. Subsequently, we exposed the calli to varying concentrations of Cu-QDs (ranging from 0 to 100 mg L− 1) to assess their physiological and biochemical responses. A hormetic response was observed in this study. At 5 mg L− 1, Cu-QDs enhanced biomass production, protein content, and antioxidant enzyme activity, while reducing malondialdehyde levels. Specialized metabolite levels, including phenolics (27

This research focused on the importance of the in vitro culture for rapid multiplication of Calotropis procera, a local herb of great medicinal value in Iran. It also looked at the employment of a suitable elicitor for increasing its growth and therapeutic substances production. In this regard, initially, optimizing the culture medium for in vitro culture was performed. Next, it was assessed how multi-walled carbon nanotubes (MWCNTs) help improve growth traits, physiological parameters, element uptake, and secondary metabolites of C. procera. Here, quarter-strength MS basal medium was considered as an optimal medium for in vitro culture of C. procera. Studying the impact of different amounts of MWCNTs (0, 100, 200 and 400 mg L−1) on the growth and physiological parameters showed a dose-dependent effect of MWCNTs. After 4 weeks of treatment, growth of seedlings, their chlorophyll contents, antioxidant compounds, and the uptake of essential nutrients incresed at 200 mg L−1 MWCNTs, and then a decline was observed at 400 mg L−1. Increased activities of superoxide dismutase and ascorbate peroxidase, and carotenoids accompanied with lower amounts of essential elements at 400 mg L−1 MWCNTs suggested that the high concentration of MWCNTs might induce oxidative stress. Additionally, 200 mg L−1 MWCNTs greatly increased the amounts of phytochemical markers in C. procera seedlings including camphor, linalool, p-cymene, germacrene D, citronellal, geranial, and citronellol. Generally, these results solidify the claim that MWCNTs treatment under in vitro cultures is a good alternative approach for increasing the biomass and biosynthesis of antioxidants in C. procera. This work shows that multi-walled carbon nanotubes can be a potent elicitor to boost biomass and biosynthesis of pharmacological metabolites of Calotropis procera under in vitro conditions

The interactive effects of multi-walled carbon nanotubes (MWCNTs) and salinity stress on tomato (Solanum lycopersicum L.) callus, focusing on callus induction, growth, redox homeostasis, nutrient uptake, and secondary metabolism, were investigated. Using a two-step in vitro system, callus was induced on full-strength MS medium supplemented with 0.5 mg L−1 naphthaleneacetic acid (NAA) and 2.5 mg L−1 6-benzylaminopurine (BAP), followed by a 21-day exposure to NaCl (100.0 mM) and MWCNTs (0.0, 100.0, and 150.0 mg L−1). Treatment with 100.0 mg L−1 multi-walled carbon nanotubes (MWCNTs) significantly improved biomass production, particularly under salt stress, and also enhanced uptake of Ca2+, Fe2+, and PO43− and stimulated antioxidant mechanisms. Under salinity, 100.0 mg L−1 MWCNTs reduced MDA and H2O2 levels by 62.0

Iron oxide nanoparticles (FeONPs) are widely used in various applications, such as biomedicine, environmental remediation, and agriculture. Moreover, FeONPs can affect the production of secondary metabolites in plants, which are compounds that have various biological and pharmacological activities. Therefore, in this study, the ajwain (Carum copticum L.) seeds were grown in MS medium containing different levels of FeONPs (0, 100, 200, and 400 mg l(- 1)). After four weeks, the effects of FeONPs on growth, photosynthesis pigments, total phenolic, and anthocyanin content, activities of some antioxidant enzyme and secondary metabolites of ajwain) were investigated. The results showed that low levels of FeONPs (especially 200 mg l(- 1)) increased fresh weight (231 %), total chlorophyll (49 %), total phenolics (259 %), anthocyanin content (110 %), as well as thymol (8 %) and gamma-terpinene (16 %) content. Conversely, 400 mg l(- 1) FeONPs reduced root length (60 %) and fresh weight (64 %) was associated with a reduction in CAT activity, phenol (55 %), thymol (22 %), and gamma-terpinene (18 %) content compared to ajwain treated with 200 mg l(- 1) FeONPs. This reduction was probably due to the increase in ROS caused by the low catalase enzyme activity and important essential oils compounds such as thymol and gamma-terpinene. Thus, our results indicate that FeONPs at certain levels can be used as a new way for in vitro production of valuable essential oils and antioxidant compounds in ajwain.

In vitro drought stress has a considerable impact on the mass production of active compounds in medicinal plants. Nevertheless, photosynthesis, nutrient uptake, and protein synthesis may be negatively affected by drought, which results in poor growth. Titanium dioxide nanoparticles (TiO2 NPs) have recently been shown to play an important role in increasing nutrient uptake, resistance to various environmental stresses, and better plant growth. Regarding the importance of pharmaceutical metabolites of Melissa officinalis L., this experiment aimed to assess the role of TiO2 NPs in improving physiological responses and phytochemical properties in M. officinalis under in vitro drought stress. For this, two-week-old seedlings were cultured on Murashige and Skoog (MS) medium supplemented with 0, 50, and 100 mg L−1 TiO2 NPs and 0, 3, and 6

Drought stress has a critical role to reduce plant growth and also alter composition and quantity of secondary metabolites. Secondary metabolites generally have been used in medicinal and food industry. Moreover, application of bio-chemical compounds such as chitosan has been reported to enhance tolerance of plants under abiotic and biotic stress. Therefore, this study was carried out to illuminate how chitosan functions in response to drought stress and its effect on secondary metabolism in Carum copticum L. (ajwain) under in vitro condition by calculating some physiological parameters and secondary metabolites content. Seedlings and callus of ajwain were cultured in MS medium with 0, 3 and 6

This work centered on developing an efficient hairy root induction system to achieving a high production capacity of specialized metabolites in Calotropis procera (Aiton) W.T. Aiton. Accordingly, three strain types of Agrobacterium rhizogenes, two different explants (leaf and internodal stem segment), and inoculation suspension containing ½MS medium with 3 and 6 improvement of their growth and physiological characteristics by Fe3O4 nanoparticles and salicylic acid.

Higher production of secondary metabolites is one of the adaptive responses to alleviate the impact of environmental injuries. In the present investigation, the production of these metabolites with medicinal importance induced by salinity in Carum copticum was investigated. To develop a better way for the production of medicinal substances, callogenesis and plant regeneration were analyzed, and seeds, calli, and/or regenerated seedlings were exposed to different concentrations of NaCl under in vitro culture conditions. The maximum frequency of callus induction was obtained on a medium supplemented with 0.25 mg L−1 2, 4-dichlorophenoxyacetic (2,4-D) and 1 mg L−1 benzyl amino purine (BAP) from stem explants. Plant regeneration with multiple shoots was obtained from pieces of callus transferred to MS medium fortified with 0.25 mg L−1 2,4-D and 1.5 mg L−1 BAP. Four weeks after treatment, salinity induced a substantial increase in the accumulation of reducing sugars and proline as compatible osmolytes and the activity of antioxidant enzymes. Total phenolics and anthocyanin significantly increased in all samples with increasing NaCl concentrations; however, the regenerated seedlings showed a reduction in these compounds at severe NaCl concentration compared to the control. Moreover, NaCl enhanced thymol, γ-terpinene, sabinene, and myrcene in the seedlings and calli, as well as carvacrol, limonene, and α-terpinene in the regenerated seedlings. These results suggest that salinity has a marked impact on improving the content of antioxidant metabolites and essential oils in C. copticum, whose callus might be the most salt tolerant in all tested samples.

Calotropis procera presents high levels of medicinally important terpenes and phenolics with antiinflammatory, antimicrobial, and antioxidant properties. The present study aimed to develop a suitable platform for mass production of pharmacological metabolites and improvement of antioxidant activity of C. procera. Motivated by such aim, potential effects of magnetic nanoparticles (MNPs) and salicylic acid (SA) on antioxidant defense response and essential oils in seedlings and hairy roots were investigated. 21-day-old seedlings were treated by five levels of MNPs (0, 50, 100, 150, and 200 mg L −1 ) and three SA concentrations (0.0, 0.05, 0.1 mM). Moreover, the hairy roots about 2 cm were transferred into MS liquid medium supplemented with the above-mentioned concentrations of MNPs and 0 and 0.01 mM SA. After treatment, total phenolics, flavonoids, flavonol, anthocyanin, activity of polyphenol oxidase and L-phenylalanine ammonia-lyase, ferric-reducing antioxidant power, 2, 2‑diphenyl‑1‑picrylhydrazyl and production of essential oils were analyzed. Our results demonstrated that hairy root culture is a powerful alternative for improving and inducing secondary metabolites of C. procera as compared to seedlings. Moreover, it was found that MNPs combined with SA have the more ability than all other treatments to improve antioxidant activity and essential oil in both seedlings and hairy roots. Here, 100 and 200 mg L −1 MNPs combined with 0.01 mM SA had more pronounced impact on induction of pharmacological constituents and antioxidant activity. Results suggest that MNPs and SA in hairy root culture can bring great insights into development in vitro biosynthesis of valuable secondary metabolites.

Abstract One way to reduce the use of chemical fertilizers without harming plant nutrition and increase the absorption of nutrients in crops is to use biostimulants. Seaweed extracts is one of the plant biostimulants that is used in agricultural systems because of their potential for improving nutrient use efficiency, resistance to stressors, and product quality. In this study, the effects of aqueous extract of a green macroalgae (Ulva flexuosa) and a brown macroalgae (padina) at four levels (dilutions 5, 10, 20 and 40%) as well as NPK chemical fertilizer at one level (concentration 0/625 mg/ml) on the growth of basil (Ocimum basilicum L.) was examined for 45 days. The results showed that the effect of brown algae extract on germination was more significant while 5% dilution of green algae increased plant root length. Treatment with both green and brown macroalgae extracts improved biochemical parameters. The highest amount of chlorophyll, carotenoids and anthocyanins was observed in dilution of 20% and the highest amount of flavonoids, phenol and reducing power was observed in 10% dilution of brown macroalgae extract.

The present study was carried out to elucidate effects of synthesized magnetic nanoparticles (MNPs) on morphological and physiological parameters and main essential oil components of Calotropis procera seedlings. For this purpose, 21-day-old seedlings grown under hydroponic conditions were treated by the different MNP concentrations (0, 50, 100, 150, and 200 mg L-1). The results showed that the growth parameters, chlorophyll pigments, soluble sugars, and total proteins significantly increased in leaf under MNP treatment, except for the root length. As compared to the control, MNPs induced a substantial change in the activities of antioxidant enzymes, H2O2, and malondialdehyde contents. Ascorbate peroxidase activity showed a meaningful increase in leaf treated with 200 mg L-1 MNPs, while superoxide dismutase activity and concentration of H2O2 conspicuously decreased relative to the control. Moreover, MNPs enhanced geranial, 1,8-cineol, a-phellandrene, citronellal, camphor, and terpinen-4-ol contents as major components. These results suggest that MNPs could be a promising method of iron application in agricultural systems. Regarding the effects of MNPs, 200-mg L-1 MNPs were most effective on the production of main essential oils and plant growth that could serve as a favorable elicitor for plant improvement.

Carum copticum L. is a medicinal plant of the Apiaceae family with medicinal properties. In this study, the effects of UV-B radiation on the photosynthetic pigments and essential oils as well as phenols and anthocyanin of the seedling and callus of C. copticum were investigated under in vitro conditions. For this purpose, the experiment was set up in a completely randomized design, with three replicates per treatment. The seedlings and calli of Ajwain were categorized in two groups: the first group served as control and the second group was exposed to artificial UV-B radiation for 30 min at 15 days. The results indicated UV-B treatment reduced fresh weight about 34% and 27% compared with control in seedlings and calli respectively. The amount of chlorophyll a, b and total chlorophyll as well as carotenoids decreased about 36%, 42%, 38% and 14% in seedling and 24%,32%, 26% and 14% in callus of C. copticum respectively under UV stress. The lowest and highest amounts of flavonoids and anthocyanin were observed at UV-B treatment and untreated plants respectively. In addition, The UV-B stress changed the compounds of the essential oil both in the seedlings and the calli of C. copticum. Analysis of the essential oil constituents showed thymol and gamatherpinen, the main essential oil components of C. copticum, increased under UV-B radiation. While, p-cymene concentration decreased under UV treatment Therefore, C. copticum is useful for the in vitro production of pharmaceuticals and other beneficial substances by plant tissue culture techniques under UV-B treatment.

Drought is one of the most important growth limiting factors in plants. The great extent of drought-prone land and the scarcity of water resources have drawn much attention to drought related issues. In this study, in order to investigate the effect of silicone on some morphological, physiological and molecular characteristics of Iranian Borago under drought stress conditions, a factorial experiment was conducted in a completely randomized design with 3 replications. For this purpose, 14-day-old Borago seedlings were treated with silicone (0, 0.5 and 1.5 mM) and drought (with polyethylene glycol at three concentrations of 0, 9 and 12%) under hydroponic conditions. Morphological and physiological parameters were evaluated 5 weeks after treatment. The results showed that drought significantly reduced the growth parameters, chlorophyll a, total chlorophyll and carotenoids contents compared to the control. Silicon treatment reduced the negative effects of drought stress and increased growth parameters and photosynthetic pigments. Also, drought stress caused significant increase in anthocyanin, carbohydrates (soluble and reducing sugar), glycine betaine, proline contents, and increased expression of BADH and P5CS genes. Combined drought and silicon treatments significantly reduced the expression of BADH and P5CS genes and the products of these two genes, proline and glycine betaine, in comparison to drought stress samples, which confirms the role of silicon in reducing osmotic stress in the present study.

Chitosan is a natural nontoxic biopolymer, which is indicated as an aid for reducing oxidative injury caused by salt stress. To explore the potential effects of chitosan on the production of secondary metabolites and antioxidant activity of Carum copticum L., commonly known as Ajwain, seedlings and callus under in vitro salt stress, total phenolics, protein content, antioxidant enzyme activities, and essential oil contents were measured. Two-week-old C. copticum was cultured on MS medium containing 0, 10 and 20 mg L−1 chitosan and 0 and 100 mM NaCl. Calli induced on MS medium supplemented with 4 μM benzyl amino purine and 1 μM 2, 4-dichlorophenoxyacetic acid were cultured on MS medium containing 4 μM BAP, 1 μM 2, 4-D, and different concentrations of chitosan with 100 mM NaCl. The total phenolics, protein content, and antioxidant enzyme activities significantly increased in callus cultures and seedlings under NaCl treatment, except for the root phenolic content. On the other hand, chitosan suppressed phenolic accumulation and antioxidant enzyme activities under NaCl treatment. Furthermore, both NaCl and chitosan enhanced the contents of thymol and p-cymene in seedlings and calli. No significant difference was observed between calli and seedlings. Regarding the effects of chitosan, 20 mg L−1 chitosan found to be most effective on phenol content with increased production of thymol and p-cymene, and it could serve as a favorable excipient for the pharmaceutical industry. These results suggest that plant tissue culture techniques are a promising approach for improving the production of target secondary metabolites through abiotic elicitors supplemented to the medium.

BACKGROUND:Chitosan is a polycationic polysaccharide derived from chitin that has been recognized as an effective elicitor in the production of secondary metabolites of many medicinal plants. In this study, the effect of abiotic elicitor (chitosan) at various concentrations on rosmarinic acid (RA) and total phenolic accumulation in shoot cultures of lemon balm was investigated.RESULTS:Treatment of shoots by chitosan led to a noticeable induction of phenylalanine ammonia-lyase (PAL), catalase (CAT), guaiacol peroxidase (GPX) and lipoxygenase (LOX) activities. Besides, the expression of PAL1, TAT and RAS genes and accumulation of RA and phenolic compound increased in chitosan-treated lemon balm shoots. Chitosan treatment also increased H2O2 accumulation and the expression of RBOH, an essential gene implicated in ROS production. Also, the up-regulation of the OPR gene by exogenous chitosan was associated with the induction of endogenous JA determined by GC-MASS.CONCLUSION:The present study showed that the induced production of rosmarinic acid by chitosan involves the trigger of defense-related enzymes, up-regulated expression of TAT and RAS genes, and stimulation of JA biosynthesis.

Morphological and physiological parameters of polyethylene glycol (PEG)-induced drought-stressed Thymus vulgaris L. (thyme) seedlings were examined. To start in vitro selection for drought stress tolerance and to provide a more efficient method for the production of pharmaceutical substances, callus induction and production of essential oils were analyzed. Thyme seeds were germinated on medium containing 0, 2, 4, 6, and 8% (w/v) PEG; and, for callus induction, stem explants were cultured on medium supplemented with 1 mg L−1 2,4-dichlorophenoxyacetic acid with different concentrations of PEG. Four weeks after PEG-induced water stress, a significant decrease in seedling growth, chlorophyll and carotenoid contents, and callus weight and induction was observed. However, no significant difference was found in the germination rate of seeds. Organic osmolytes, e.g., proline and carbohydrates, were influenced by PEG-induced osmotic stress. Reducing sugars progressively increased with rising PEG concentrations, while proline levels largely decreased under severe water stress. Moreover, PEG decreased the anthocyanin content but raised reactive oxygen species (ROS), lipid peroxidation, proteins, and phenolic compound levels. Additionally, PEG induced a substantial change in the activities of antioxidant enzymes. Positive relationships between ascorbate peroxidase activity and formation of ROS in PEG-treated thyme seedlings were detected. Furthermore, PEG changed the essential oil composition in seedlings and calluses by significantly increasing γ-terpinene, p-cymene, and geraniol but decreasing thymol and carvacrol. Thus, mild stress levels increased phenolics and oil components in thyme, despite the extent of oxidative injury and growth reduction, which could enhance secondary metabolite production in vitro.

D. kotschyi is a source of essential oils with medicinal properties such as antihyperlipidemic, immunomodulatory, antinociceptive and cytotoxic effects. This study aimed to investigate whether the application of chitosan can improve plant growth, increase secondary metabolite production and help antioxidant enzymatic systems in Dracocephalum kotschyi under in vitro culture. Tow-week-old seedlings of D. kotschyi were cultured in MS medium containing 0, 5, 10 and 20 mg.L -1 chitosan. Four weeks after treatments, the enzymatic and morphological parameters were measured and the GC/MS analysis was used to evaluate the secondary metabolites. Application of chitosan resulted in changes in physiological and morphological responses. It had a beneficial effect on the main essential oil contents such as thymol, p-cymene and candinol (16.2%, 20.3% and 34% increasing, respectively). In spite of reduction of antioxidant activities and growth, 20 mg/l had a positive effect on the oil components in D. Kotschyi.

Increase in secondary metabolites content has been attracting interest recently due to their huge economic importance. For example, Artemisia aucheria, which produces artemisinin, has both medicinal and economical importance. The aim of this study was to investigate the effect of single or combination UV radiation as well as sampling time on biochemical-physiological properties of A. aucheria on the increase in secondary metabolites, especially artemisinin. Therefore, a completely randomized factorial design including 7 radiation (no UV, UV-A, UV-B, UV-C, UV- (A + B), UV- (A + C) and UV- (B + C)) and Two different sampling times ( 2 and 24 hours after treatment) was carried out in three replicates. The results indicated that the content of chlorophyll a, b and total chlorophyll decreased in response to all UV radiation conditions except for UV-A. Moreover, the highest decrease of photosynthetic pigments was observed in the UV-(B+C). In addition, the concentration of photosynthetic pigments was reduced through time. In contrast, the content of carotenoids in plants treated with UV-A was increased. Moreover, total flavonoid content was increased about 50% in response to UV-(A+C). Further, the delay in sampling was shown to be associated with an increase in the concentration of flavonoid. Generally, all types of UV radiation, except for UV-C, increased the concentration of artemisinin and most of the other essential oils in both sampling times. Although the highest concentration of artemisinin was observed in the plants treated with UV-(B+C), the usage of UV-B, UV-(A+B) and UV-(A+C) radiation is suggested for increasing the artemisinin content in the short time