Background: Most nanoparticles (NPs) have a significant impact on the structure and function of the plant photosynthetic apparatus. However, their spectrum of action varies significantly, from beneficial stimulation to toxicity, depending on the type of NPs, the concentration used and plant genotypic diversity. Photosynthetic performance can be assessed through chlorophyll a fluorescence (ChlF) measurements. These data allow to indirectly obtain detailed information about primary light reactions, thylakoid electron transport reactions, dark enzymatic stroma reactions, slow regulatory processes, processes at the pigment level. It makes possible, together with leaf reflectance performance, to evaluate photosynthesis sensitivity to stress stimuli. Results: We investigated effects of different metal and metal(oid) oxide nanoparticles on photosynthesis of oakleaf lettuce seedlings by monitoring the chlorophyll a fluorescence light radiation and reflectance from the leaves. Observations of ChlF parameters and changes in leaf morphology were carried out for 9 days in two-day intervals. Spectrophotometric studies were performed at 9^th day. Suspensions of NPs with the following concentrations were used: 6% TiO₂, SiO₂; 3% CeO₂, SnO₂, Fe₂O₃; 0.004% (40 ppm) Ag; 0.002% (20 ppm) Au. Nanoparticles were applied directly on the leaves which caused small symptoms of chlorosis, necrosis and leaf veins deformation, but the plants fully recovered to the initial morphological state at 9^th day. Leaf reflectance analysis showed an increase in FRI for SiO₂-NPs and CeO₂-NPs treatments and ARI2 for Fe₂O₃, however, WBI and PRI coefficients for the latter nanoparticle were lower than in control. Chlorophyll a fluorescence parameters have changed due to NPs treatment. Fe₂O₃-NPs caused an increase in F_v/F₀, PI_ABS, ET₀/RC, DI₀/RC, ABS/RC in different time points in comparison to control, also Ag, Au and SnO₂ treatment caused an increase in F_v/F₀, PI_ABS or ET₀/RC, respectively. On the other hand, TiO₂-NPs caused a decrease in F_v/F_m and F_v/F₀ parameters, but an increase in DI₀/RC value was observed. SnO₂-NPs decreased PI_ABS, but increased ET₀/RC than compared to control. Nanoparticles affected the shape of the O-J-I-P curve in slight manner, however, further analyses showed unfavourable changes within the PSII antenna, manifested by a slowdown in the transport of electrons between the Chl molecules of the light-harvesting complex II and the active center of PSII due to NPs application. Conclusion: Changes in ChlF parameters and leaf reflectance values clearly proved the significant influence of NPs on the functioning of the photosynthetic apparatus, especially right after NPs application. The nature of these changes was strictly depended on the type of nanoparticles and sometimes underwent very significant changes over time. The greatest changes in ChlF parameters were caused by Fe₂O₃ nanoparticles, followed by TiO₂-NPs. After slight response of O-J-I-P curves to treatment of the plants with NPs the course of the light phase of photosynthesis stabilized and at 9^th day were comparable to the control curve.

In the present study, we investigated the irrigation of L. angustifolia plants and drying temperatures on the yield of dry leaves and lavender essential oil. Plants were irrigated using an on-surface system with drip lines. Plants without additional irrigation were the control object. Each dose of water consisted of 15 mm. The total amount of water used for irrigation in 2016 and 2017 was 90 L·m⁻². The plant raw material was dried using two methods: in natural conditions and convectively. Natural drying was performed in a shaded room at a temperature of 20–22 °C for five days. The convective drying process was carried out in a drying oven in a stream of air at 35 °C, flowing parallel to the layer being dried at 0.5 m·s⁻¹. Under the influence of irrigation, there was an increase in the yield of fresh and airdried leaves and a higher content of essential oil (EO) than in the cultivation without irrigation. The EO obtained from irrigated plants was characterized by higher contents of caryophyllene oxide (9.08%), linalool (7.87%), and β-caryophyllene (4.58%). In nonirrigated crops, α-muurolol (19.67%), linalyl acetate (15.76%), borneol (13.90%), γ-cadinene (8.66%), camphor (2.55%) had a higher percentage in the EO. After drying under natural conditions, the airdried herb yield and leaf yield of lavender were higher by 25% and 17%, respectively, as compared to the raw material dried at 30 °C. Higher drying temperatures (30 °C) increased the EO by 18% on average and total phenolic acid (TPA) by 50%. The plant material dried at 30 °C, with a larger amount of TPA, showed higher antioxidant activity (AA) in the 2,2-diphenyl-1-picrylhydrazyl (DPPH) tests. Linalyl acetate (15.76%) and linalool (7.87%) were predominant in the EO extracted from the oven-dried herb. Drying under natural conditions resulted in a decreased content of linalyl acetate (0.89%), β-caryophyllene (0.11%), linalool (1.17%), and camphor (1.80%) in comparison with thermal drying. Linalool, linalyl acetate, and β-caryophyllene had a higher percentage in the EO extracted from the raw material obtained from irrigated and oven-dried plants, whereas camphor was found to have a larger percentage in the case of the EO from nonirrigated plants. Our study reveals that there are prospects for the practical use of irrigation in lavender cultivation and of the raw material preservation method in order to modify the EO content and chemical composition.

Tansy (Tanacetum vulgare L.) is an aromatic medicinal plant whose use is limited by the presence of toxic thujone. This research aimed to evaluate the morphological and chemical properties of tansy plants growing in various natural habitats. The research determined the content and chemical composition of the essential oil, the contents of flavonoids and phenolic acids, and the antioxidant activity levels of methanol extracts from tansy inflorescences. The highest amount of essential oil (1.05 mL·kg⁻¹) was found in the raw material collected from the reclaimed area (R). Forty-seven compounds were identified in tansy oil, among which camphor (31.21–1.27%) and trans-chrysanthenyl acetate (76.09–0.09%) dominated, while the concentration of trans-thujone was low (2.67% on average). The highest amounts of flavonoids (0.52%) were found in the raw material collected from the ruderal (W) and reclaimed (R) sites, while the highest amount of phenolic acids (2.42%) was found in the raw material from the ruderal site (W). Tansy inflorescence extracts showed high antioxidant potential (88.41%). The reasons for the variability of the chemical composition of tansy were environmental and genetic variability factors.

Artichoke herb is of great pharmaceutical importance, mainly due to the high content of phenolic compounds. This paper presents the effect of late nitrate (N) fertilization with mineral and organic N on the yield of air-dried herb, the total content of polyphenolic acids (TCQA), the polyphenolic profile as well as on the antioxidant activity (AA). These parameters were measured in organic (ORG) and conventional (CON) cropping systems. The principal outcomes revealed that the highest TCQA content was determined in the herbal extracts of ORG management treatments with late N fertilization of 20 kg ha⁻¹. This result explained the highest AA content of the extract in the ABTS+ (2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid)), FRAP (ferric-reducing antioxidant power), and DPPH (2,2-diphenyl-1-picrylhydrazyl) assays. Late N fertilization increased the content of cynarin and ferulic acid in both systems. In addition, chlorogenic acid increased between 37% and 45% in the CON cropping systems depending on the fertilizer dose. In the same treatment, luteolin increased 39% compared to the control. Lastly, in the ORG management system, caffeic acid and apigenin content increased 10% and 30%, respectively. Both treatments showed high collinearity values, where ORG systems were related to ferulic acid and cynarin, and CON systems were associated with chlorogenic acid and AA potential (ABTS, DPPH, FRAP). To sum up, ORG cropping systems can obtain an acceptable yield size with a high-quality content of bioactive compounds, allowing a better understanding of the effect of N fertilization in ORG and CON cropping systems.

Living mulch (LM) provides many beneficial agro-ecological services by reducing soil evaporation, conserving moisture, controlling soil temperature, reducing weed growth, increasing organic matter and nutrient availability, and improving microbial activities. Legumes, commonly used as living mulches, can affect the yield and quality of main crops. We hypothesized that Egyptian clover co-cultivated with Cynara cardunculus var. altilis (cultivated cardoon) can positively affect both leaf biomass and phytochemical yield. The study was performed on two growing seasons of field experiments to evaluate the potential variation in biomass and phytochemical yields of cardoon leaves. In addition, the leaves were collected at 90, 120, and 150 days after transplanting to evaluate the possible effect of the harvest time. LM improved the fresh and air-dried leaves biomass yields, total phenolic, and dry matter content, while it had no effect on the content of crude fibre, total sugars, L-ascorbic acid, total chlorophylls, and antioxidant activity. Except for luteolin-7-O-glucoside content, no negative effect of LM was observed on the polyphenol profile. Behind the cultivation system, the parameters were also affected by both the harvest time and growing season. According to our data, the proposed intercropping of cultivated cardoon with LM could represent an innovative cultivation system to increase both leaf biomass and the health-promoting compounds of cultivated cardoon leaves by sustainable soil management.