The wood of the common oak (Quercus robur L.) has high mechanical strength, elasticity and resistance to fracture. However, constitutional stability is not always able to provide the plants with reliable protection from wood-decay fungi, and the initial stages of biodegradation are difficult to determine. Therefore, this study concerns research on appropriate biochemical markers for early diagnostics of wood defects. The total content of phenolic compounds in leaves and wood was determined by a spectrophotometer Optizen Pop using Folin & Ciocalteu’s phenol reagent; the flavonoid content in leaves – by adding solutions of aluminum chloride and sodium acetate to methanolic extracts; catechins content – by the reaction with vanillin reagent; the concentration of phenolic antioxidants – by Brand Williams; chlorophyll and carotenoids’ contents in leaves – by the formula for methanol extracts; the qualitative composition of phenolic compounds – by high performance liquid chromatography and highly effective thin-layer chromatography. During the planned felling of oak trees on the territory of the Boyar Forest Research Station, trees were found with signs of brown streak and biodestruction of wood. Brown streak in wood is caused by a polycondensation of phenolic compounds, which are deposited on the internal surfaces of tracheal elements. In cases of an increase in the total amount of oxidized polyphenols, the cell walls are also stained. Active oxidation processes in wood have a systemic nature for the plants and affect the physiological state of the assimilation apparatus. We determined that in leaves of the trees with signs of brown streak the total phenol content increases in comparison with the control by 1.6 times, as well as flavonoid and catechin content. Our research has shown that the complex of plastid pigments in common oak leaves does not significantly change in the early stages of destructive processes. Increase of brown streak and appearance of rot in wood are associated with slight increase in chlorophyll a to b ratio in leaves. Chromatographic profiling of the leaves showed that the presence of brown streak changes the content of individual phenolic compounds. The trees with brown rot have more substances with UV spectrum characteristic for kaempferol glycosides compared to the control. The results have shown that the biochemical profiles of the trees with signs of brown streak and brown rot differ from the control by the composition of low and medium polar compounds. The absence or presence of some individual phenolic components and their ratio in the leaves are considered as biochemical markers of hidden wood defects.
The article considers the effect of chitosans of different origin, molecular weight, and degree of deacetylation on the dynamics of phenolic substances in the leaves of Fragaria ananassa Duch. These substances potentially act as agents in plant responses to biotic stresses. We showed that the daily variations in individual phenolic compounds are most pronounced in the group of ellagitannins and kaempferol-3-b-D-[6-O-(E)-coumaroyl]-glucopyranoside. The most stable indicators were concentrations of kaempferol glycoside and ellagic acid pentoside. The strongest plant response to leaf treatment with low-and high-molecular-weight chitosans was a significant increase in the concentration of hexahydroxydiphenyl (HHDP)-glucose in leaves, peaking at 12 h after treatment. Treatment of F. ananassa with various forms of chitosans resulted in different concentrations of the basic phenolic substances. In particular, the plant response to a single treatment with 0.4% low-molecular-weight chitosan (LMC) was accompanied by a significant decrease in the ellagic acid concentration, after a slight increase in the first hour after treatment. The opposite effect was observed in plants after treatment with high-molecular-weight chitosan (HMC). We also determined the daily dynamics for the quantitative and qualitative composition of phenolic compounds in the control group of plants. By using the Biplot analysis, we showed a clear difference between phenol concentrations in the evening (0, 24, and 48 h) and in the morning (12 h). The strongest difference was an increase in the concentration of HHDP-glucose, galloylquinic acid, ellagic acid pentoside, kaempferol glycoside, and ellagic acid in leaves in the morning, followed by a decrease in the evening and nighttime, due to the physiological reactions of plants to external abiotic and biotic factors.
The article describes the differentiation of collection samples of marigold at Experimental station of medicinal plants using cluster analysis as to sixteen components of the group of flavonoids, highlighted with high performance liquid chromatogram. The selected six clusters, which are characterized by the complex of economically valuable sings: plant height, diameter of the bush, productivity of plants by dry inflorescences and seeds, weight of 1000 seeds, vegetation period and the content of total flavonoids. We developed and presented numerical score for each of these sings of the six clusters. According to the results of the integrated valuation we found the highest amount of points at the samples of cluster 5, which was 35 points. The selected varieties of marigold of the fifth cluster such as Radio, Berezotits’ka sonyachna, Oranzhevyy blysk, and a sample Co-12-115 were found to be promising for future use in the selection process.
The effect of soil moisture on the content of biologically active substances in the dry roots with rhizomes of valerian cultivation of plants with drip irrigation is researched. The possibility of obtaining high-quality raw materials harvest of valerian for one year of cultivation is determined. It is proved that the use of drip irrigation provides roots with dry rhizomes containing extractives at 35.87–39.54% essential oil — 5.7–6.4 ml/kg and the amount of sesquiterpene acids — 0.23–0.30% depending on the soil moisture. The contents of all three active ingredients meet the requirements of the State Pharmacopoeia of Ukraine and European Pharmacopoeia.
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