Stevia rebaudiana Bertoni is a valuable plant whose products are increasingly used in medicine, pharmacy and the food industry. This necessitates the use of biotechnological approaches for its mass propagation. Establishing optimal conditions for in vitro cultivation is essential for obtaining high biomass and secondary metabolites production. A large number of articles considering the role of plant growth regulators and other additives in the culture medium in the growth and development of Stevia are available in the literature. However, there are no summarized data about the use of nanoparticles in Stevia tissue cultures. Therefore, this review also includes the research conducted so far on the effect of nanoparticles on Stevia micropropagation. Furthermore, the influence of different elicitors on secondary metabolite production and antioxidant activity of in vitro-cultivated Stevia plants have been discussed. By referring to the collected literature, we concluded that biotechnological approaches applied to S. rebaudiana cultivation might improve the agronomic traits of plants and steviol glycosides production.

The food industry is interested in replacing artificial sweeteners with natural sugars that possess zero calories and carbohydrates and do not cause spikes in blood sugar levels. The steviosides leaves, synthesized at Stevia rebaudiana Bertoni, are 300 times sweeter than common table sugar. Stevia propagation is limited due to the poor viability of the seeds, the long time and low germination rate, and the poor rooting ability of vegetative cuttings. Because of this, an alternative biotechnological method for its reproduction is being studied, such as multiple shoot production through direct organogenesis using nanofibers, formed from a derivative of amino acid valine as a carrier of the biologically active agent silver atoms/particles (NF-1%Ag and NF-2%Ag). The stevia explants were cultured on a medium containing NF-1%Ag and NF-2%Ag at concentrations of 1, 10, 50, and 100 mg L⁻¹. The NF-1%Ag and NF-2%Ag treatment caused hormetic effects on stevia plantlets. At low concentrations of from 1 to 50 mg L⁻¹ of nanofibers, the stimulation of plant growth was observed, with the maximum effect being observed at 50 mg L⁻¹ nanofibers. However, at the higher dose of 100 mg L⁻¹, inhibition of the values of parameters characterizing plant growth was recorded. The presence of nanofibers in the medium stimulates stevia root formatting.

Since water scarcity is one of the main risks for the future of agriculture, studying the ability of different wheat genotypes to tolerate a water deficit is fundamental. This study examined the responses of two hybrid wheat varieties (Gizda and Fermer) with different drought resistance to moderate (3 days) and severe (7 days) drought stress, as well as their post-stress recovery to understand their underlying defense strategies and adaptive mechanisms in more detail. To this end, the dehydration-induced alterations in the electrolyte leakage, photosynthetic pigment content, membrane fluidity, energy interaction between pigment–protein complexes, primary photosynthetic reactions, photosynthetic and stress-induced proteins, and antioxidant responses were analyzed in order to unravel the different physiological and biochemical strategies of both wheat varieties. The results demonstrated that Gizda plants are more tolerant to severe dehydration compared to Fermer, as evidenced by the lower decrease in leaf water and pigment content, lower inhibition of photosystem II (PSII) photochemistry and dissipation of thermal energy, as well as lower dehydrins’ content. Some of defense mechanisms by which Gizda variety can tolerate drought stress involve the maintenance of decreased chlorophyll content in leaves, increased fluidity of the thylakoid membranes causing structural alterations in the photosynthetic apparatus, as well as dehydration-induced accumulation of early light-induced proteins (ELIPs), an increased capacity for PSI cyclic electron transport and enhanced antioxidant enzyme activity (SOD and APX), thus alleviating oxidative damage. Furthermore, the leaf content of total phenols, flavonoids, and lipid-soluble antioxidant metabolites was higher in Gizda than in Fermer.

Physalis peruviana L. is one of the most favorable tropical fruit due to its fast growth and nutritional properties. The current research outlined the response to drought stress of golden berry plants inoculated with arbuscular mycorrhizal fungi Claroideoglomus claroideum and propagated in vitro as well as from seeds. The implementation of mycorrhizal symbiosis was determined by root colonization, glomalin content, and alkaline and acid phosphatases in roots and soil. The plant protection was assured by enzyme and non-enzyme antioxidants. The adapted in vitro propagated plants demonstrated higher resistance to drought than plants developed from seeds indicated by increased growth parameters (shoot, root biomass, fruit number), plastid pigment content, antioxidant activity, and less enhance mentofoxidative markers levels in water-deficient conditions. The findings in the present research are relevant to obtain the optimal mycorrhizal association and type of propagation in an adverse environment for golden berry development and will lead to the establishment of a database and model of varied plant responses to stressful conditions such as drought.