Glomus intraradices (N.C. Schenck & G.S. Sm.) C. Walker & A. Schuessle enhances nutrients uptake, chlorophyll and essential oil contents and composition in Anethum graveolens L.

Arbuscular mycorrhizal (AM) fungi are plant-root symbionts whose application in agriculture has been proven its efficiency. However, their application in medicinal plants and their impact on accumulation of essential oils (EO) is still limited. In order to investigate the effect of AM fungi (Glomus intraradices N.C. Schenck &amp; G.S. Sm.) C. Walker &amp; A. Schuessle) on nutrients uptake, biomass production, yield components, chlorophyll content, and EO content and composition in dill (Anethum graveolens L.), a field experiment was conducted as randomized complete block design with three replications. This medicinal plant was grown under AM fungi colonization and non-colonization treatments. Plant inoculation by mycorrhiza increased aerial tissues P and Fe concentrations. However, K, Ca, and Zn concentrations were not affected by AM colonization. The plants inoculated with AM significantly increased plant biomass, chlorophyll content, and EO content by 363 g m−2, 11.83 SPAD and 0.683 % in comparison with non-inoculated plants, respectively. Changes in EO composition were found in AM-colonized dill plants. The contents of myristicin, dill-ether and N-dihydrocarvone increased in EO obtained from AM-colonized plants, while AM colonization resulted in a lesser content of α-pinene, α-phellandrene, limonene, and β-phellandrene.</p

Improving seed germination and physiological characteristics of maize seedlings under osmotic stress through potassium nano-silicate treatment

IntroductionOsmotic stress can significantly affect the survival and functioning of living organisms, particularly during vulnerable stages such as seed germination and seedling growth. To address this issue, advanced technologies like nanofertilizers have been developed to improve soil conditions and enhance plant growth in stressed ecosystems due to their multiple effects and efficient consumption.MethodsThe objective of this study was to investigate the impact of potassium nano-silicate (PNS) on the physiological characteristics of maize seedlings and seed germination under various levels of osmotic stress induced by polyethylene glycol (PEG). The study considered two factors: two levels of PNS concentration (500 and 1000 ppm) and PEG-6000 solution with different osmotic stress levels (-2, -4, -6, and -8 bars).Results and discussionThe results demonstrated that the application of PNS at a concentration of 1000 ppm led to increased radicle length and hypocotyl length as well as fresh weight of maize seedlings. Furthermore, PNS at a concentration of 1000 ppm had a more beneficial effect on the germination rate of maize seedlings under osmotic stress compared to 500 ppm. Additionally, the application of PNS under osmotic stress conditions resulted in an increase in various physiological parameters, including protein content, chlorophyll a, chlorophyll b, total chlorophyll content, proline content, and the activity of catalase (CAT) and ascorbate peroxidase (AXPO) enzymes. These findings indicate that the use of PNS can have a positive impact on the physiological characteristics of maize seedlings and seed germination under osmotic stress conditions. Overall, this technology has the potential to enhance crop growth and yield in stressed ecosystems. By improving the survival and function of plants during vulnerable stages, such as seed germination and seedling growth, the application of PNS can contribute to more resilient agricultural practices and promote sustainable food production in challenging environments

Improving oil content and fatty acid composition in dragon's head grain under drought stress with exogenous salicylic acid application

The effectiveness of growth regulators, such as salicylic acid, in enhancing plant resistance to a range of biotic and abiotic stresses is well documented. Against the background of Iran's pressing water scarcity problems and the widespread cultivation of dragon's head in various industries, this study sought to investigate the influence of salicylic acid on both grain yield and oil quality of dragon's head under conditions of limited irrigation. Field experiments were conducted using a split-plot design within a randomised complete block format, replicated three times over the course of 2017 and 2018. The experimental design included different irrigation regimes, ranging from full irrigation to cessation of irrigation at critical growth stages such as flowering and branching, as primary plots. At the same time, sub-plots were subjected to different concentrations of salicylic acid (SA), namely 1, 2, 3 and 0 mM. It's noteworthy that the irrigation cut-off significantly reduced key metrics such as unsaturated fatty acid content, protein percentage, as well as grain, oil, protein and mucilage yields. Conversely, it induced an increase in saturated fatty acids in oil and mucilage percentage in grain. However, the application of SA had a discernible positive effect, increasing both grain yield and quality. The results showed that SA application, especially at a concentration of 2 mM, increased the levels of linoleic and oleic unsaturated fatty acids while reducing stearic and palmitic saturated fatty acids under drought conditions. As a result, SA application served as a potent mitigator against the adverse effects of drought stress on grain oil quality, resulting in overall improvements in product quality

Response of maize (Zea mays L.) to potassium nano-silica application under drought stress

To investigate the influence of potassium nano-silica (PNS) on maize plant under drought stress including non-stress (NS), moderate drought stress (MDS) and severe drought stress (SDS), a factorial experiment was conducted with completely randomized blocks with three replications. Drought stress decreased the concentrations in the shoot of phosphor (P), calcium (Ca), iron (Fe), zinc (Zn), manganese (Mn) and silica (Si) and nitrogen (N), P, Ca, Fe, Zn, copper (Cu), Mn and Si concentrations of seed. There was an increase in the concentration in the N seed and shoot potassium (K) concentration under drought stress. It was observed that applying PNS increased nutrient absorption. The highest concentration of N in the seed was obtained at 100 ppm PNS. The highest concentrations of seed K and N, Cu, Mn and Si in the shoot were found when 200 ppm of PNS was applied. Applying PNS had no significant effect on the concentrations of P, Ca, sodium (Na) and Cu in the seed, and of Ca and Na in the shoot. These findings demonstrate that the application of PNS can limit the negative effects of drought stress and improve plant’s resistance against drought stress.</p

Nano silver-encapsulation of Thymus daenensis and Anethum graveolens essential oils enhances antifungal potential against strawberry anthracnose

Nanotechnology is an eco-friendly strategy in managing plant diseases. In combination with existing practices nanotechnology can enhance the protection of agricultural products and food. For example, essential oils (EOs) of thyme (Thymus daenensis L.) and dill (Anethum graveolens L.) have an antimicrobial potential and this potential may be enhanced by certain nanoparticle systems. Here we demonstrate that encapsulating EOs of thyme and dill in silver nanoparticles increases their fungicidal activity against Colletotrichum nymphaeae, causing anthracnose in many horticultural crops. Using GC-MS analysis, we identified p-cymene, thymol, carvacrol and (E)-caryophyllene as the main EOs of thyme and limonene, cis-dihydrocarvone, cyclohexanon, and carvone as the main EOs of dill. When the EOs of the two sources were encapsulated in silver nanoparticles, synergistic effects against C. nymphaeae were observed, resulting in more than 80% inhibition of mycelium growth of C. nymphaeae. Moreover, conidia germination was suppressed by nano-encapsulated EOs. We also observed considerable morphological changes in the fungal hyphae when nano-encapsulated EOs were applied. Our study demonstrates the potential of encapsulated EOs in controlling pathogens that can be very applicable as antifungal agents.</p

Enhancement of the antifungal activity of thyme and dill essential oils against Colletotrichum nymphaeae by nano-encapsulation with copper NPs

Nanotechnology is a quickly growing field and have been actually used in a varied assortment of marketable products worldwide. Nanoencapsulation demonstrations the advantage of more efficient and targeted use of pesticides in an environmentally friendly way. Research and development in post-harvest nanotechnology can help to preserve food freshness and quality and prevent diseases in a relatively safer way. In this regard, essential oils (EOs) represent promising agents for reducing food decay and development of pathogen microorganisms. The overall aim of the present study was to encapsulate Iranian thyme (Thymus daenensis L) and dill (Anethum graveolens L.) EOs in copper nanoparticles (NPs) and to evaluate their antifungal activity against the phytopathogen Colletotrichum nymphaeae. Encapsulation of thyme and dill EOs with copper NPs resulted effective in reducing the mycelium growth even by 90% after 9 days treatment. Furthermore a strong inhibitory effect on conidia germination of C. nymphaeae was observed. SEM observations indicated that C. nymphaeae treated with EOs, copper NPs and encapsulated EOs, showed deformation in mycelial growth and hyphae twisting. In summary, these results showed that nano-encapsulation of EOs with NPs, using safe materials, increased the perspective of their effectiveness as new plant disease management strategies