Roman chamomile (Chamaemelum nobile (L.) All.) is a perennial herbaceous medicinal plant species that has not yet been thoroughly researched in terms of the influence of growing conditions on its morphological characteristics, flower yield, and the content and quality of its essential oil (EO). The plant material was harvested in the subsequent two production years at three localities in Southeast Serbia, differing in soil type (Alluvial soil, Rendzina, and Calcomelanosol). Based on two-year average values, the best results were obtained from plants grown on Rendzina, including the yield of fresh flowers (1850.2 g/m²), the highest plant height (49.3 cm), the number of branches (4.1), leaves (11.6), and flower heads (3.6), the flower diameter (1.6 cm), and the essential oil content (1.6%). The major EO constituent obtained from the plants growing on Rendzina and Calcomelanosol was 3-methyl pentyl angelate (20.8% and 15.2%, respectively). In the EO obtained from the plants growing on Alluvial soil, the major EO constituent was isobutyl angelate (13.0%), while the content of 3-methyl pentyl angelate was close to it (12.2%). The outcomes of this study provide guidelines for further research related to the cultivation of a Roman chamomile genotype on various soil types in a hilly region of Southeast Serbia, where most cultivated plants cannot be grown.

Paeonia peregrina Mill. is a protected, herbaceous species native to Southeastern Europe and Turkey. Due to its vulnerability, it has to be protected both in its natural habitats and through cultivation. Peonies are known to have a low potential for natural regeneration due to their seed dormancy, low germination rate, and long germination period. In this study, treatments with gibberellic acid (GA₃ 150, 200, 250, 300, and 350 mg L⁻¹ GA₃) and warm (at 20/16 °C day/night regime) and cold stratification (at 4 °C) were used to accelerate dormancy release and increase the germination rate. The seeds of P. peregrina from four natural habitats in Serbia and the Institute’s collection were collected and analyzed. They showed an underdeveloped embryo that needs to grow inside the seed before it can germinate. The application of GA₃ accelerated each stage of germination (seed coat rapturing, hypocotyl dormancy release, and epicotyl dormancy release) for approximately 10 days compared to the control. It was also found that two-day imbibition with 200 mg L⁻¹ GA₃ significantly accelerated and equalized germination. Higher GA₃ concentrations had a more pronounced impact on each stage but also resulted in greater seed infection after the seed coat rupture, elongated and weak seedlings, while lower concentrations did not result in obtaining uniform seedlings. There were no significant differences observed between localities. Restoring P. peregrina through seeds and nursery-produced plants is crucial for conserving the genetic diversity of the tested species.

Melissa officinalis L. (Lamiaceae) is a perennial plant species widely used in the pharmaceutical and food industries, particularly valued for its sedative properties. This study investigates the impact of synthetic mulch film and planting density as two experimental factors on agronomic performance, raw material quality, and economic efficiency in lemon balm production. The experiment was conducted at three locations in Serbia (L1: Bačko Novo Selo, L2: Bavanište, L3: Vilandrica) from 2022 to 2024, using two planting densities on synthetic mulch film (F1: 8.3 plants m⁻²; F2: 11.4 plants m⁻²) and a control treatment without mulch (C). The synthetic mulch film used was a synthetic black polypropylene film (Agritela Black, 90 g/m²), uniformly applied in strips across the cultivation area, covering approximately 78% of the soil surface. The results showed consistent increases in morphological parameters and yield across the years. Plant height in F1 and F2 treatments ranged from 65 to 75 cm, while in the control it reached up to 50 cm (2022–2024). Fresh biomass yield varied from 13.4 g per plant (C) to 378.08 g per plant (F2), and dry biomass yield from 60.3 g (C) to 125.4 g (F2). The highest essential oil content was observed in F2 (1.2% in 2022), while the control remained at 0.8%. The F2 treatment achieved complete weed suppression throughout the experiment without the use of herbicides, demonstrating both agronomic and ecological advantages. Economic evaluation revealed that F2 generated the highest cumulative profit (€142,164.5) compared to the control (€65,555.3). Despite higher initial investment, F2 had the most favorable cost–benefit ratio in the long term. This study highlights the crucial influence of mulching and planting density on optimizing lemon balm production across diverse climatic and soil conditions, while also underscoring the importance of sustainable, non-chemical weed management strategies in lemon balm cultivation.

The steppe peony (Paeonia tenuifolia L.) is an endangered medicinal plant species that occurs in Serbia in three habitats, of which the Deliblato Sands is the richest. Based on the results of research conducted at Deliblato Sands in 2023, it was found that the development of the flowering stems of Paeonia tenuifolia was not affected by the slightly higher average winter temperatures. One hundred randomly selected plants were measured in the field, including height, plant girth, number of branches per plant bush, the ratio of flowering to non-flowering branches, shoot-toroot ratio, and stem-to-branch-to-flower ratio. The results showed that the root-to-shoot ratio was 1:2.5, the average height of the tested plants was 41±6 cm, ranging from 30-60 cm, and the girth of the plant bush was 121±30 cm, ranging from 40-170 cm, and was positively correlated with the number of branches. The average number of branches per plant was 8±2.5. Based on the measurement of the absolute dry plant material, it was found that the mass of a branch contained on average 22.5% of the stem, 73.5% of the leaf twigs, and 4% of the flower mass. The petals make up, on average, 34.3% of the mass of the flower.

Seed health testing aims to ensure a healthy crop and to prevent the spread of plant diseases. The need to study and apply both essential oils and plant extracts against seed diseases is growing and becoming more important. Coriander (Coriandrum sativum L.) is an annual herbaceous, aromatic, spicy and medicinal plant from the Apiaceae family, known for its seeds with a characteristic and pleasant odour. In human medicine, coriander is a part of various medicines for the treatment of digestive organs. Phytopathogenic fungi and bacteria are the most common and significant causes of coriander seed disease. The aim of this study was to assess coriander seed health and investigate the possibility of seed disinfection using peppermint (Mentha x piperita) essential oil. The health of the seeds was examined by the filter paper laboratory standard method. Different concentrations (1, 2, 5 and 10%) of peppermint essential oil were used for seed disinfection. The composition of the essential oil was determined by gas chromatographic analysis. The results of seed health analysis showed the presence of a fungus after seven days of incubation in a humid chamber at room temperature. The fungus was identified as Alternaria sp. (sect. Alternaria) based on the symptoms and macroscopic and microscopic features of the fungus (on seed and potato dextrose agar). Immersion treatment of infected seed in peppermint essential oil reduced the presence of Alternaria sp. on coriander seeds. The highest disease inhibition, 69,33%, namely 58,93% without the influence of the emulsifier, was shown by oil solution of 5%. Stagnation in inhibition was observed with a further increase in oil concentration. The results of this study show the possibility of disinfecting coriander seeds with peppermint essential oil to reduce infection with Alternaria sp.

Paeonia peregrina Mill. and Paeonia tenuifolia L. are endangered species of herbaceous plants with high ornamental and medicinal values. There are a few natural habitats in Serbia where these plants spontaneously grow: Krivi Vir, Skrobnica, Golina, Pirot, Deliblato Sands, and Sokobanja, in the municipality of Knjaževac. In July 2021, the symptom of leaf spots was observed on P. peregrina, while spots on leaves, stems, and lower branches on P. tenuifolia in the localities of Pirot and Deliblato Sands. Disease incidence was estimated to 32% in Pirot and 25-35% in Deliblato Sands. Therefore, the aim of the study was to identify the causal agent of leaf spot on P. peregrina and P. tenuifolia in Serbia by molecular identification and characterization, and morphological characterization. For molecular identification and characterization, nuclear ribosomal internal transcribed spacer (ITS) region, partial translation elongation factor 1-alpha (EF-1α), beta-tubulin (TUB2) and histone 3 (H3) genes were amplified using primer pairs ITS1/ITS4, EF1-728F/EF1-986R, T1/Bt2b, and H3-1a/H3-1b, respectively. Morphological characterization of the representative isolates was done on potato dextrose agar (PDA) and potato carrot agar (PCA) media at 22 ◦C under an 8 h light:16 h dark regime. Based on the molecular and morphological characteristics of the obtained isolates, Alternaria alternata was identified as thecausal agent of leaf spot on P. peregrina and P. tenuifolia. In Serbia, to the best of our knowledge, this is the first report of A. alternata causing a leaf spot of P. tenuifolia.