The aim of this study was to determine the effects of pre-sowing seed treatment with cold plasma (CP) and an electromagnetic field (EMF) on the agricultural performance of two cultivars of common buckwheat (Fagopyrum esculentum Moench)—‘VB Vokiai’ and ‘VB Nojai’. For this, the effects of CP and EMF on seed germination, plant growth in the field, photosynthetic efficiency, biomass production, seed yield, and the amount of secondary metabolites and minerals in the harvested seeds were estimated. Although the percentage of seedlings that emerged under field conditions decreased by 11–20%, seed treatments strongly improved buckwheat growth and yield. Irrespective of differences in the dynamics of changes in the growth and photosynthetic activity between the two cultivars, the weight of seeds collected per plant for both cultivars was significantly higher (up to 70–97%) compared to the control. The biochemical composition of the harvested seeds (Fe, Zn, quercetin content) was also altered by seed treatments. Thus, pre-sowing treatment of buckwheat seeds with CP and EMF substantially stimulated plant growth in the field, increased biomass production, seed yield and nutritional quality. The results obtained strongly support the idea that plant seed treatment with physical stressors has great potential for use in agriculture.

Aeroponic plant cultivation is a novel technology explored for its potential in indoor farming. In this study, we evaluated the effects of seed treatments with cold plasma on growth, physiological processes, and biochemical parameters in two lettuce cultivars—green variety ‘Perl Gem’ and red variety ‘Cervanek’ cultivated in an aeroponic system for 45 days. Seeds were treated with low-pressure air plasma for 3 min (further denoted as LCP3) or atmospheric dielectric barrier discharge (DBD plasma) for 3 and 5 min (referred to as DBD3 and DBD5 groups). We estimated the effects of seed treatments on parameters of seedling growth, photosynthetic efficiency, amounts of photosynthetic pigments, anthocyanins, total phenolic compounds (TPC), and antioxidant activity in leaves. Despite the observed effects on germination and early growth, seed treatments did not affect biomass gain or head/root ratio in both lettuce cultivars. Seed treatments increased the photosynthetic performance index and amounts of photosynthetic pigments in ‘Pearl Gem’ but not ‘Cervanek’ leaves. Seed treatments enhanced the content of protective phenolic compounds and antioxidant activity in ‘Pearl Gem’, and anthocyanin content in ‘Cervanek’ leaves, indicating potential to improve the nutritional value of the edible part of lettuce cultivated in an aeroponic system.

The aim of this research was to assess the effect of different fertilization on barley and millet resistance to drought stress under current and warmed climates. Barley grown with organic fertilizers showed 3.8 and 5.6% lower losses of photosynthetic rate than plants grown with mineral fertilizers, at current and warmed climates respectively. Enrichment with organic fertilizers also resulted in lower and insignificant trapped energy flux losses of barley due to drought in warmed climate compared to losses in fertilization with mineral when the negative drought effect was significant. The production of enzymatic antioxidants in barley, in warmed climate and drought conditions, increased by 44% more due to organic fertilization than due to mineral fertilization. The aforementioned changes in indicators resulted in different drought resistance under different fertilization, as drought resistance index of barley fertilized with organic fertilizers was statistically significantly higher, compared to plants fertilized with mineral fertilizers in both investigated climates. Meanwhile, a statistically significant difference between the changes in millet resistance was found only under current climatic conditions. Study reveals that different fertilization changed the physiological and biochemical response of barley and millet to drought stress, and that organic fertilizers were more effective for plants resistance to drought.

This work focuses on the investigation of competition interaction between C3 crop barley (Hordeum vulgare L.) and C4 weed barnyard grass (Echinochloa crus-galli L.) at 2 times higher than ambient [CO2] and +4 0C higher ambient temperature climate conditions. It was hypothesized that interspecific competition will change the response of the investigated plants to increased [CO2] and temperature. The obtained results showed that in the current climate conditions, a higher biomass and photosynthetic rate and a lower antioxidant activity were detected for barley grown under interspecific competition effect. While in the warmed climate and under competition conditions opposite results were detected: a higher water use efficiency, a higher photosynthetic performance, a lower dissipated energy flux and a lower antioxidant enzymes activity were detected for barnyard grass plants. This study highlights that in the future climate conditions, barnyard grass will become more efficient in performance of the photosynthetic apparatus and it will suffer from lower oxidative stress caused by interspecific competition as compared to barley.

The impact of foliar spray fertilizers (Aton Az) on the resistance of spring barley (Hordeum vulgare L.) against to individual and combined UV-B radiation and drought effects were investigated. Barley seeds were sown in pots prepared with neutral pH peat substrate. When the 2^nd true leaf unfolded, i.e. 7 days after germination, the first spray with microelement and free amino acid fertilizers was carried out; two days after this application, the different irradiation (1 and 3 kJm^–2 d^–1) UV-B doses and drought effects were started. Exposure lasted for 6 days. The main characteristics of all investigated indicators were assessed at the end of exposure. The largest positive effects of fertilizers on the photosynthetic rate and water use efficiency of barley were found solely under the impact of drought. Foliar spray fertilizers decreased oxidative stress injury in the leaves by decreasing the malondialdehyde content under solely effects of drought and UV-B radiation, while under the combined effect of the mentioned stress factors, the changes were statistically insignificant. A stronger positive impact of foliar fertilization was detected on the content of photosynthetic pigments (a and b) at solely UV-B radiation effect than at combined effect of investigated factors, when significant changes were detected only in individual cases.