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Seed germination is a complex process that can be negatively affected by numerous stresses. Trichoderma spp. are known as effective biocontrol agents as well as plant growth and germination stimulators. However, understanding of the early interactions between seeds and Trichoderma spp. remains limited. In the present paper, Fourier-transform infrared spectroscopy (FTIR) and Raman spectroscopy were used to reveal the nature of tomato seed germination as stimulated by Trichoderma. A rapid response of tomato seeds to Trichoderma spp. was observed within 48 h on Murashige and Skoog medium (MS) substrate, preceding any physical contact. Raman analysis indicated that both Trichoderma species stimulated phenolic compound synthesis by triggering plant-specific responses in seed radicles. The impact of T. harzianum and T. brevicompactum on two tomato cultivars resulted in alterations to the middle lamella pectin, cellulose, and xyloglucan in the primary cell wall. The Raman spectra indicated increased xylan content in NA with T9 treatment as well as increased hemicelluloses in GZ with T4 treatment. Moreover, T4 treatment resulted in elevated conjugated aldehydes in lignin in GZ, whereas the trend was reversed in NA. Additionally, FTIR analysis revealed significant changes in total protein levels in Trichoderma spp.-treated tomato seed radicles, with simultaneous decreases in pectin and/or xyloglucan. Our results indicate that two complementary spectroscopic methods, FTIR and Raman spectroscopy, can give valuable information on rapid changes in the plant cell wall structure of tomato radicles during germination stimulated by Trichoderma spp.

Calluna vulgaris (L.) Hull. is an evergreen perennial plant of the Ericaceae family possesses noteworthy pharmacological properties and has long been used in traditional medicine for addressing many medical conditions [1]. A plethora of bioactive compounds have been discovered in C. vulgaris, with phenolics being the primary source of its diverse health benefits, including antioxidant, anti-inflammatory, and antimicrobial properties, among others [2, 3]. However, a detailed study of its antiradical activity has not been conducted before. Herein, the supercritical CO2 extraction of C. vulgaris branches has been employed to obtain an extract rich in polyphenolic compounds. Supercritical CO2 extraction, a green technology method, replaces classical solvent-based extraction, enabling the isolation of plant compounds in their purest form without degradation of the sample [4]. Owing to its high sensitivity and specificity, Electron paramagnetic resonance (EPR) spectroscopy has been utilized to access the extract's scavenging activity against free radical species (DPPH and hydroxyl radicals). The spin-trapping technique was employed to detect activity against short-lived hydroxyl radicals. The results demonstrate that the C. vulgaris branch extract is a significant free-radical scavenger. It exhibited remarkable selectivity in eliminating hydroxyl radicals (68.5% compared to 21.7% for DPPH), which is particularly noteworthy as hydroxyl radicals are considered the most reactive oxygen radical species, biologically relevant, and responsible for a number of pathologies. These findings underscore the therapeutic potential of C. vulgaris branch extract in combating oxidative stress-related medical conditions but also suggest possibilities for further investigation into its mechanism of action and formulation into pharmaceutical or nutraceutical products.

Crop yield increases with a sustained increase in leaf photosynthesis. Due to many limitations, plants do not sufficiently use their photosynthetic capacity. Carbon dots (CDs) have a high light harvest capability, which may be used to improve the photosynthesis efficiency of plants. In this study, nontoxic orange CDs (o-CDs) were foliarly applied to boost the maize (Zea mays L.) and green beans (Phaseolus vulgaris L.) productivity in the field. Leaves of both plant species were sprayed three times with 1 and 5 mg/L of the o-CDs aqueous solutions in equal intervals during the vegetative growth stage until flowering. To find the best geometries for CO2 adsorption on o-CD, modeling of o-CDs-CO2 interaction was performed. Photosynthesis parameters and fruit yield were measured during plant growth. Total phenolic content and antioxidative activity were monitored as oxidative stress indicators. Computational simulations and spectroscopic measurements suggest that o-CDs, acting as a “CO2 delivery” system, can enhance photosynthetic efficiency. Photosynthesis was enhanced in both plant species, but only green beans showed an increased fruit yield. CO2 use in tested species was discussed in light of two mechanisms. Plant species show different, but no significant antioxidative responses. The chemical surface composition has shown that o-CDs were not contained in either the leaves or fruits of the treated plants. The results indicate that o-CDs may be applied as a simple and safe biostimulator on plants. That could have an environmental benefit in capturing CO2 in the atmosphere.