Clinopodium pulegium (Rochel) Bräuchler (Lamiaceae) is an endangered species endemic to the Southern Carpathians. It is characterized by the production of high amounts of essential oils, which emit volatile organic compounds (VOCs) that have an essential role in biotic and abiotic stress responses and in plant–plant and plant–insect interactions. The present study was initiated to phytochemically examine the influence of different carbon sources in the nutrition medium on VOC emissions of micropropagated C. pulegium plants, using gas chromatography–mass spectrometry analysis of headspace VOCs. The volatile profiles were subjected to multivariate analysis with respect to the presence, concentration and type of carbon source in the nutrient medium. In addition, the effect of different carbohydrates on the density and size of the leaf glandular trichomes, the main structures involved in the emission of VOCs, was determined. A total of 19 VOCs, primarily belonging to mono- and sesquiterpenes previously described in plants, were tentatively identified. Six VOCs were produced at levels higher than 2% of the total VOC emission, dominated by pulegone, ß-pinene and menthone. Inclusion of the carbohydrates in the culture media affected the production of the main leaf trichome-associated volatile allelochemicals although the qualitative composition of the volatiles changed only slightly. Multivariate analysis showed that the concentration, rather than the carbohydrate type, influenced the VOC profile.

Pinus peuce (Macedonian pine) is considered a valuable ornamental tree that is frequently planted in parks and gardens, especially in Western Europe. This endemic pine is one of the most valuable conifer species in its native range, which currently consists of only two disjunct populations restricted to small mountainous areas of the Balkans and is listed as a near-threatened species. The reproduction of Macedonian pine by seed is limited, so in vitro propagation methods have emerged as a promising tool for large-scale propagation. The objective of this study was to develop an improved system for the micropropagation of P. peuce from juvenile plant material using a short-term liquid cytokinin pulse. For that, explants derived from 4-week-old seedlings were pulse-treated with different concentrations of N⁶-benzyladenine (BA) for 1 or 2 h to stimulate the induction of axillary buds. The highest axillary shoot formation was achieved with 222 µM BA pulse treatment, with an average number of ~six shoots per explant. Elongated shoots (≥10 mm) were detached from the explants and pulse-treated with 0.27 or 1.08 mM α-naphthaleneacetic acid (NAA) or 0.25 or 0.98 mM indole-3-butyric acid (IBA) for 1 or 2 h. IBA was more effective than NAA and led to a maximum rooting percentage (up to 40%) and the highest number of acclimatized plants (15–20%). Rooted plants were successfully transferred to ex vitro conditions.

Micromeria graeca (L.) Benth. ex Rchb. (Lamiaceae) is a promising medicinal plant valued for its antioxidant, anti-hyperglycemic, anti-hypertensive, antimicrobial, and anti-aflatoxigenic properties. It is rich in phenolic and flavonoid compounds, supporting its traditional use for digestive, respiratory, cardiovascular, and dermatological conditions. Plant tissue culture facilitates controlled in vitro propagation to study plant growth and bioactive properties. The effects of activated charcoal and varying subculture intervals on multiplication and biomass production in M. graeca shoot cultures were investigated. The phenolic composition of methanolic extracts from in vitro-grown plants was characterized using high-performance liquid chromatography (HPLC), identifying rosmarinic, caffeic, and syringic acids as the primary phenolic compounds. Antimicrobial activity against selected microbial strains was evaluated using a micro-well dilution assay. Anticancer activity of selected extracts was assessed in human hepatocellular carcinoma cell line HepG2, with flow cytometry (Annexin-V/PI staining) used to analyze cell death mechanisms, and compared to pure rosmarinic acid (RA). Activated charcoal showed no beneficial effects on multiplication or biomass production, but significantly increased phenolic acid content (up to 4-fold). RA dominated the phenolic profiles, with other phenolic acids present in lower amounts. Methanolic extracts exhibited negligible antimicrobial activity compared to reference antibiotics and fungicide. Extracts from 4-week-old shoot cultures displayed modest anti-hepatoma activity (IC50 values of CV assay ranging from 193 to 274 µg mL⁻¹), inducing HepG2 cell apoptosis via oxidative stress, independent of RA. Our results suggest that the metabolic output of M. graeca shoot cultures and consequently their biological activity can be modulated by varying in vitro culture conditions. These findings underscore the potential of their methanolic extracts for biotechnological production and therapeutic applications.

Somatic embryogenesis (SE) represents the most efficient and scalable technology for the mass clonal propagation and genetic improvement of superior conifer genotypes, which is crucial for meeting global wood demand and supporting forest adaptation to climate change. Despite its immense potential, SE in the genus Pinus still faces major limitations, including low initiation frequencies, restricted explant availability, and pronounced genotype dependence. This review synthesizes current knowledge on the factors influencing SE in Pinus species, with a specific focus on two ecologically vital Tertiary relicts endemic to the Balkan Peninsula: Pinus peuce (Macedonian pine) and Pinus heldreichii (Bosnian pine). For these species, traditional vegetative propagation methods are difficult or ineffective, making SE the priority approach for clonal propagation. Detailed studies on these species revealed that SE induction is highly dependent on the explant type and developmental stage. Successful embryogenic tissue formation was achieved only from whole megagametophytes containing immature zygotic embryos, within a narrow developmental window spanning 4–10 weeks post-fertilization. Furthermore, medium composition, particularly reduced ammonium concentration, proved critical for P. heldreichii success. These findings underscore the need for continued, species-specific optimization to overcome current bottlenecks and realize the full potential of SE for the conservation and sustainable clonal forestry of these high-value pines.