Azim Ghasemnezhad

Extended Abstract Background: Medicinal plants play a crucial role in human nutrition and the treatment of numerous diseases due to their ability to produce secondary metabolites with therapeutic properties. Silybum marianum L., a medicinal plant belonging to the Asteraceae family, contains silymarin as its principal bioactive compound, which is widely used in ...

The present study investigated the effect of growth regulators on the quantity and quality of calli of two yew genotypes (Taxus spp.). A factorial experiment based on a completely randomized design was performed using 2,4-D and kinetin on leaf and stem explants of T. baccata and T. brevifolia. Calli traits, including fresh weight, total phenols, total alkaloids, and paclitaxel contents were investigated. The simple effect of hormonal treatments on total phenolic content, total alkaloids, and fresh weight of calli was significant. Total phenols content and fresh weight were not much affected by the interaction of hormonal treatments, whereas total alkaloids content was found increased. Paclitaxel content did not significantly differ between explants. The highest paclitaxel content was found in the leaf explant of T. baccata (30 μg/g), compared to 5 and 10 μg/g in T. baccata stem, T. brevifolia stem, and T. brevifolia leaf, respectively. The fresh weight and total alkaloid content of stem calli of both species were higher than the leaves. Yew is a valuable endangered medicinal plant that responds well to in vitro treatments. Therefore, it is possible to manage the production of its valuable metabolites under in vitro conditions.

Endophytic fungi pass all or at least a part of their life cycle inside or between host cells in living plant tissues. These fungi are not capable of causing disease in the host plants, however, they are deemed to be associated with the production of some secondary metabolites in plants. Therefore, this study was laid out to shed light on how fungicides are involved in the formation of key metabolites of yew (Taxus baccata L.), especially taxol. Through the symbiotic fungal endophyte activities and population changes an experiment was conducted as a completely randomized block design using two foliar application treatments of Rovral‐TS and Fosetyl aluminium fungicides. Plants sprayed with distilled water were used as a control. The findings revealed that the diversity of endophytic fungi declined with the application of systemic fungicides, leading to a decrease in the production of certain secondary metabolites. Specifically, the levels of paclitaxel decreased by 35%, while the photosynthetic pigments chlorophyll‐a, chlorophyll‐b and total chlorophyll decreased by 26%, 20.6% and 19.6%, respectively. Additionally, the levels of carotenoids, total phenol and total flavonoids decreased by 18%, 15% and 21.8%, respectively. The highest amount of these compounds was observed in the control treatment. An increase in antioxidant activity, soluble sugars and proline content was observed soon after fungicides application. The variation in the content of soluble sugars, proline and antioxidant activity was fungicide‐dependent. Compared to Fosetyl aluminium fungicide, the numerical value of the above parameters in plants treated with Rovral‐TS was 14.4%, 11.7% and 25.4% higher, respectively. The fungicide‐mediated induction of Taxol production—key secondary metabolites in yew—was to a great extent associated with the change in endophytic fungi. This further establishes the role of fungal endophytes in the stimulation of secondary metabolite formation in yew plants.

Utilization compounds like salicylic acid is one of the ways to control the salinity and reduce the damage of salinity. Salicylic acid is a phenolic compound plays a role as signaling molecule in plant tolerance system, to protect plants against stresses. The experiment was done to evaluate the effect of salinity ...