Phenolic compounds (PCs) in plants play an important role in growth control and have antioxidant, structural, attractant, signaling and protective functions. Information on the discovery, study and identification of phenolic compounds in plants, their role in the complex system of secondary metabolites has been analyzed and summarized. The functions of PCs at the macromolecular, cellular as well as organism and population levels are described. The pathways of PCs formation, enzymes responsible for their synthesis and the plasticity of the synthesis in a plant cell are highlighted. The involvement of PCs in the plant breathing, photosynthesis, oxidation-reduction processes and regulation of the plants physiological state are discussed.

Buckwheat genus (Fagopyrum Mill.)

The affordable and scalable synthesis of noble metal nanoparticles that are biocompatible without additional functionalization steps has been a growing field of research, stimulated by numerous prospective applications of these NPs. In the case of phytosynthesized or biogenic noble metal NPs, the mechanism of NP stabilization by biomolecules contained in each particular plant extract or living organism determines the possible applications of these NPs. In this work, we investigated Ag NPs synthesized in water with plant extracts of common toothwort (Lathraea squamaria) and two species of pepper (Capsicum annuum and Capsicum chinense). From FTIR and XPS, we drew conclusions about the composition of the functional groups and molecules that stabilize NPs in each extract, such as polysaccharide compounds (pectins, cellulose, glycosides and phenolic acids). Distinct characteristic IR features of amide I and amide II proteins were observed, which are common in plant extracts, while features of amide III were not distinctly observed in our extracts. A Raman spectroscopy study revealed weak own-SERS activity of the biomolecules of the extract and high efficiency of the NPs in the enhancement of “external” analytes, such as dyes and antibodies. This is the first report of the efficient SERS application of phytosynthesized Ag NPs.

The use of colloidal solutions of metals as micronutrients enhances plant resistance to unfavorable environmental conditions and ensures high yields of food crops. The purpose of the study was a comparative evaluation of presowing treatment with nanomolybdenum and microbiological preparation impact upon the development of adaptive responses in chickpea plants. Oxidative processes did not develop in all variants of the experiment but in variants treated with microbial preparation, and joint action of microbial and nanopreparations even declined, as evidenced by the reduction of thiobarbituric acid reactive substances in photosynthetic tissues by 15 %. The activity of superoxide dismutase increased (by 15 %) in variant “nanomolybdenum” and joint action “microbial + nanomolybdenum,” but it decreased by 20 % in variants with microbial preparation treatment. The same dependence was observed in changes of catalase activity. Antioxidant status factor, which takes into account the ratio of antioxidant to pro-oxidant, was the highest in variants with joint action of microbial preparation and nanomolybdenum (0.7), the lowest in variants with microbial treatment only (0.1). Thus, the results show that the action of nanoparticles of molybdenum activated antioxidant enzymes and decreased oxidative processes, thus promoting adaptation of plants.

Green synthesis of different nanoparticles using the plants aqueous extracts has several advantages over other methods due to the environmentally favorable nature of plants. moreover, such approach is also cost effective. This work describes the biosynthesis of silver nanoparticles (Ag-NPs) with the use of the aqueous extract of dry pericarps of hot chili peppers and cv. Carolina Reaper) with different levels of pungency and their antibacterial effect on the antibiotic resistant Pseudomonas aeruginosa. Phytochemical screening of pericarp tissues showed great distinction in contents of phenolic compounds and capsaicinoids as potential reducing agents wich correlated with total antiradical activity as analyzed by reduction of DPPH radicals. The biosynthesized Ag-NPs were characterized by UV-vis spectrophotometry and scanning electron microscopy (SEM). The average size of the nanoparticles in both samples was less than 25 nm. Іnitial concentration of both samples of Ag-NPs inhibited P. aeruginosa growth with equal efficiency.

No abstract

Flavonoids are important secondary plant metabolites with many and diverse key functions that belong to largest class of substances produced by plants-phenylpropanoids. These substances are of interested among plant and animal biochemists, plant pathologists, geneticists and biotechnologists. Flavonoids rutin and anthocyanin as herbal compounds characterized by physiological activity of a wide action spectrum: antiulcer, vitamin, antioxidant, stabilizing, ultraviolet radiation protecting, antitumor, tannic, etc. Therefore much attention has been attracted to biosynthesis of flavonoids and methods of its regulation and controlling. We determined concentration (2%) of growth regulator Cycocel (chlormequat chloride, CCC) that significantly raised anthocyanin and rutin levels in buckwheat (Fagopyrum esculentum Moench.) plants. Thin-layer chromatography revealed an increase in total flavonoids content in leaves of test plants, which was: by 3.5 times for rutin and by 8 times for anthocyanin. The same concentration of CCC had induced phenylalanine ammonia-lyase activity by 2 times. Moreover, an increase in the flavonoids content correlated with enzyme activity induction. Thus, the growth regulator Cycocel is an activator of flavonoids metabolism. Treatment by CCC significantly increased content of secondary flavonoid metabolites and activity of phenylalanine ammonia-lyase-flavonoids biosynthesis regulatory enzyme.

Wheat genus belongs to the main grain crops in Ukraine and in the world. An important element of its cultivation technology, which affects productivity, is the use of high yield varieties resistant to biotic and abiotic stressors.Therefore, the aim of a study was evaluation of polyethylene glycol-modeling drought stress adaptive responses of different varieties of wheat germs (Triticum aestivum and Triticum dicoccum) on such parameters as water shortages, relative water content, roots damage membranes and dehydrogenase activity and photosynthetic pigments content.Studied varieties of common bred wheat and emmer wheat presented resilience-anisohydric response maintaining high relative water content, increasing of root length / shoot length ratio and maintaining the ratio of photosynthetic pigments in response to drought with marked differences among the varieties. According to the result of the research Holikovska variety (Triticum dicoccum) is the most drought-resistant variety which makes it promising for use in breeding for drought tolerance. Because of resilience-anisohydric behaviour patterns might be the beneficial strategy for growing under drought stress conditions.