Artemisinin extracted from Artemisia annua has been used efficiently in malaria treatment since 2005. In this study, the variations in plant parameters (plant biomass, glandular trichome density, essential oil total chemical content, artemisinin production, and polyphenol oxidase (PPO) activity) were tested under different soil types (Luvisol, Gleysol, Anthrosol and sterile peat) and cultivation conditions (potted plants in semi-open field, and open field experiments) for plants inoculated with arbuscular mycorrhizal fungus (AMF) Rizophagus irregularis. Under semi-open field conditions, the AMF colonization of A. annua plant roots varied, and presented the highest percentage in Luvisol and sterile peat. The increase in the root colonization rate positively influenced some plant parameters (biomass, glandular trichome density, artemisinin concentration, essential oil quantity and composition), but no effects on PPO enzyme activity were detected. AMF fungus R. irregularis significantly increased the artemisinin content and essential oil yield of plants cultivated in Luvisol, Gleysol, Anthrosol and in peat. These soil types can offer appropriate conditions for A. annua cultivation and artemisinin production even on a smaller scale. Under open field conditions, low (about 5%) AMF colonization was observed. No differences in artemisin contents were detected, but essential oil yield significantly increased compared to control plants. AMF treatment increased beta-farnesene and germacrene D concentrations in Artemisia plants in the open field experiment.

Studies conducted in controlled environments showed that seed priming and foliar treatments with various bioactive substances can stimulate germination, uniform seedling emergence, photosynthesis, and nutrient uptake efficiency and can lead to increased productivity, crop stand, and quality. Only a few studies provide a comparative experimental outlook about the use of the bioactive substances in open-field cultivated canola. The aim of this study was to investigate the effects of seed priming and foliar treatment with ascorbate (AsA), cysteine (Cys), and triacontanol (Tria) on the growth and yield parameters of two canola cultivars rapeseed cultivars (“Factor” and “Hybrirock”) under open-field conditions for three growing seasons under temperate conditions from Central Transylvania. Plant growth and yield parameters were recorded at different plant development stages: in autumn (early vegetative period), in spring, and at harvest. Not all substances that have undergone laboratory testing were successful in the field. Seed priming with 10 ppm Cys and AsA had beneficial effects on the development of seedlings, whereas their foliar application enhanced the number of silique, seed yield, and the oil content of the studied canola cultivars. The effects of Tria were visible on the biometrics parameters only in autumn and spring, and also on the root parameters, but in some cases, 10 ppm Tria had no effect on plants, or even a negative effect could be observed on important parameters for agriculture such as estimated seed yield, seed yield/plant, and oil content. Optimizing treatment and application by determination of the lowest effective concentration, together with the frequency of treatments and persistence effects are crucial for cost-effectiveness.

During the study, the seeds of seven sweet basil cultivars were treated with 100 ppm solutions of gibberellic acid or ascorbic acid prior to a 14-day germination experiment. Values of the first day of germination, germination energy, germinability, mean time and rate of germination, and uncertainty and synchrony of germination were calculated. The results show that both of the substances altered the measured parameters, priming with gibberellic acid proving to be a more effective way to enhance the germination of basil seeds. Also, they revealed major differences among the germination parameters of the examined cultivars.

Seeds of industrial hemp have high nutritional and healthcare value, which can be further improved by proper cultivation methods. Biochemical properties of hemp seeds that are beneficial for human use can be modulated through variation of the molar ratio between the inorganic nitrogen and phosphorus supplied with the nutrient medium, as well as by creating a moderate water deficit during controlled irrigation. The aim of this study was to investigate the influence of two N:P ratios (i.e. 8 mM nitrogen as nitrate to 2 mM phosphorus as phosphate, and 3 mM nitrogen to 6 mM phosphorus), combined with two water supply regimes (sufficient and insufficient) on vegetative growth parameters, seed production, seed oil, protein, vitamin E, iron, zinc and manganese content of two industrial hemp cultivars (‘Jubileu’ and ‘Zenit’). The experiments were performed in a greenhouse, under controlled conditions. Even if plants receiving a lower N:P ratio and lower water supply had a decreased growth index and the shoot fresh weight was smaller, no statistically significant difference could be registered in the seed production of the different experimental variants. The oil content of seeds could be increased by a lower N:P ratio and by water deficit, while seed protein content was higher upon a higher N:P ratio and upon water shortage, for both cultivars. The highest vitamin E content of hemp seed oil was found when plants were subjected to the combined influence of lowered N:P ratio and water insufficiency. The iron content of seeds showed no changes between the different experimental variants. In seeds of the ‘Jubileu’ variety the zinc content was increased by water shortage when the N:P ratio was lower, while the highest manganese content was measured when plants received sufficient water and lowered N:P ratio. As for the ‘Zenit’ variety, the highest zinc and manganese content of seeds was obtained when plants received through the nutrient solution 8 mM nitrate and 2 mM phosphate (i.e. the N:P ratio was 4:1). The findings may contribute to optimization of hemp cultivation, in a cost-effective and environmental-friendly approach, for the purpose of production of higher quality seeds for human and animal consumption, as well as for the cosmetic industry.

During the study, the characteristics of flower heads and seed yield of marigold (Calendula officinalis L.) plants harvested at different stages of seed maturity (achenes from different types of heads – primary, secondary, and tertiary ramifications) were measured. The number of total flower heads (inflorescences), heads with mature seeds, and the diameter of heads with mature seeds and weight of seeds of the above mentioned fractions per plant were calculated. The results show that there are significant differences among treatments regarding several parameters. The plants were harvested when 90% of the heads formed on the primary ramifications and 75% of the heads formed on the secondary ramifications, having mature seeds superior to plants with 50% of the secondary heads with mature seeds.