Comparing Non-Thermal Plasma and Cold Stratification: Which Pre-Sowing Treatment Benefits Wild Plant Emergence?

Non-thermal atmospheric plasma treatments enhance the growth, photosynthesis, metabolite accumulation, and nutritional value of geranium (Pelargonium graveolens L'Herit) leaves

This study investigated the effects of non-thermal atmospheric plasma (NTAP) treatment on the growth, chemical composition, and biological activity of geranium (Pelargonium graveolens L'Herit) leaves. NTAP was applied at a frequency of 13.56 MHz, exposure time of 15 s, discharge temperature of 25 °C, and power levels (T1 = 50, T2 = 80, and T3 = 120 W).Results demonstrated significant increases (P < 0.05) in fresh and dry biomass at all treatment levels compared to control, with the highest improvements seen in T3. Mineral content (K, P, Ca, Fe, Mg, Zn, and N) was significantly elevated, particularly at T3. Chlorophyll content (a + b and carotenoids) also showed marked increases across all treatments, correlating with enhanced photosynthetic rates. Improved photosynthesis led to enhanced accumulation of primary metabolites, such as amino acids, organic acids, and fatty acids. NTAP treatments, mainly T3, significantly increased levels of essential and non-essential amino acids, oxalic, isobutyric, and fumaric acids. They also enhanced unsaturated fatty acids, such as oleic acid (C18:1), and saturated fatty acids, including myristic (C14:0) and stearic (C18:0). These improvements provided precursors for the synthesis of secondary metabolites, particularly phenolics. The increased phenolic content in turn explained the improved antioxidant capacity observed in Fluorescence Recovery After Photobleaching FRAP, anti-lipid peroxidation, superoxide radical scavenging, and hydroxyl radical scavenging assays, especially at T2 and T3 treatments. Antimicrobial activity was elevated across all treatments, with the T3 treatment notably inhibiting all tested bacterial and fungal strains, particularly Sarcina lutea.In conclusion, NTAP treatment significantly improved growth, biomass, and the phytochemical profile of geranium leaves, enhancing their antioxidant and antimicrobial properties, thereby increasing the potential nutritional and therapeutic value of the plant.

Non-Thermal Plasma (NTP) Treatment of Alfalfa Seeds in Different Voltage Conditions Leads to Both Positive and Inhibitory Outcomes Related to Sprout Growth and Nutraceutical Properties

Non-thermal plasma (NTP) has proven to be a green method in the agricultural field for the stimulation of germination, growth, and production of nutraceutical compounds in some cases. However, the process is far from being fully understood and depends on the targeted plant species and the NTP used. In this work, we focus on the production of alfalfa sprouts from NTP-treated seeds under different voltage conditions. A flexible electrode configuration was used to produce the NTP, which can also be placed on packages for in-package treatments. The surface of the seeds was analyzed, indicating that the microstructure was strongly affected by NTP treatment. Biometric measurements evidenced the possibility of stimulating the sprout growth in some conditions by up to 50% compared to the sprouts obtained from untreated seeds. Biochemical traits for the sprouts obtained in different processing conditions were also studied, such as the concentrations of chlorophyll pigments, flavonoids and polyphenols, and antioxidant activity. Most NTP treatments led to inhibitory effects, proving the strong dependence between NTP treatment and targeted plant species.

Genetic and Environmental Factors Affecting Seed Germination

Plants have evolved various strategies allowing them to be successful in heterogeneous habitats, including the number and size of the seeds they produce, mechanisms for their dispersal, seed dormancy, seed vigor, seed germination, etc [...].