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In growing maize, an increase in the content of phenolic compounds and selected phenolic acids in soil was found after the incorporation of white mustard, buckwheat, spring barley, oats and rye mulches into the soil. The highest content of phenolic compounds in soil was found after oats mulch incorporation (20% more than in the control soil). The highest content of selected phenolic acids was found for the soil with the oats and rye mulch. Among the phenolic acids investigated, ferulic acid was most commonly found in the soil with the plant mulches. However, two phenolic acids: the protocatechuic and chlorogenic acid, were not detected in any soil samples (neither in the control soil nor in the mulched soil). At the same time, a decrease in the primary weed infestation level in maize was found in the plots with all the applied plant mulches, especially on the plots with oats, barley and mustard. The plant mulches were more inhibitory against monocotyledonous weeds than dicotyledonous ones. During high precipitation events and wet weather, a rapid decrease in the content of phenolic compounds in soil and an increase in the primary weed infestation level in maize were observed.
Our objective was to determine the content of macro- and micronutrients, toxic heavy metals as well as total phenols in 10 broccoli (Brassica oleracea var. italica) cultivars. The experiment was designed at the Poznań University of Life Sciences, Poland, and completed during two plant growing seasons. Broccoli seedlings were planted in a field in early July and the plants were harvested between September and October. The content of general forms of nitrogen was measured by distillation with the Kjeldahl method. The content of potassium, calcium and sodium was assessed by flame photometry, and the content of magnesium, cadmium, lead, nickel, copper, zinc, manganese and iron was determined by flame atomic absorption spectroscopy (FAAS). The content of heavy metals, macronutrients and sodium in the broccoli heads depended on a cultivar. Having analyzed the levels of macronutrients in ten broccoli cultivars, it was concluded that cv. Agassi and Tradition had the highest content of nitrogen and phosphorus. A very high amount of phosphorus was also found in cv. Beaumont. The highest concentrations of calcium and potassium were found in cv. Monte Carlo. The cultivars Agassi, Beaumont, Tiburon and Tradition were characterized by the highest content of magnesium. The highest content of sodium occurred in the cultivars Beaumont and Monopoly. With respect to micronutrients, the highest content of iron, copper, zinc and manganese was revealed in cv. Agassi. The highest content of nickel was determined in the cultivars Beaumont and Monte Carlo. In addition, the cultivar Monte Carlo was characterized by the highest content of lead, and Beaumont had the highest content of cadmium. However, the maximum permissible levels of cadmium and lead were not exceeded in the heads of the ten broccoli cultivars. In both years of the study, the highest content of phenols was found in cv. Steel and the lowest one appeared in cv. Agassi.
The main objective of this study was to determine the effect of cultivation technologies (extensive vs. high-input) on correlations between wheat grain quality parameters, such as falling number value, wet gluten content and grain hardness, and the content of phenolic compounds, such as total free phenolic compounds and alkylresorcinols. ąIt was found high values of correlation coefficient between falling number value and wet gluten, and among analysed groups of polyphenols. Grain hardness was associated with content of wet gluten and falling number values. Additional significant correlations were observed inside each cultivar. Determined technological value indices (falling number value, wet gluten content and grain hardness) were primarily dependent on the cultivation technology, whereas the contents of the phenolic compounds and alkylresorcinols were mostly related to the wheat genotype.
The tested material consisted of grapevine Vitis californica stratified seeds germinated under optimum conditions (+25°C in water), under osmotic stress (-0.2 MPa in PEG solution) and submitted to recovery after stress (+25°C in water). The germinating seeds were determined to contain tannins, catechins and the following phenolic acids: gallic, caffeic, p-coumaric and ferulic. The acids occurred in free, ester- and glycoside-bound forms. The dominant form of phenolic acids was the ester-bound fraction. Gallic acid was the most abundant phenolic acid in germinating seeds, while ferulic acid appeared in the smallest amounts. Our analysis of tannins demonstrated that osmotic stress depressed their concentration. Presence of catechin group compounds such as catechin and epicatechin was also determined. In each sample epicatechin was dominant. The total concentration of catechin increased under stress conditions and declined during post-stress recovery. Catechins are a constituent of tannins and their increase under osmotic stress is most probably caused by the breakdown of some tannins in seeds germinating under stress conditions. Samples submitted to osmotic stress were also found to contain less of total phenolic compounds, whereas in samples which underwent post-stress recovery the total level of phenolic compounds increased. Compared to extracts from seeds germinating under optimum conditions, osmotic stress depressed the capacity of extract to scavenge DPPH● (2,2-diphenyl-1-picrylhydrazyl) and ABTS●+ – 2,2-Azino-bis (3-etylbenzothiazoline-6- -sulfonic acid) free radicals, but the antioxidant activity rose in seeds submitted to recovery after stress. Positive correlation was therefore demonstrated between the total content of phenolic acids in germinating grapevine seeds and the reducing power of extracts obtained from these seeds and their free radical scavenging activity. The results suggest that osmotic stress inhibits the activity of antioxidizing enzymes in germinating grapevine seeds. Thus, the antioxidative defence system is largely blocked under osmotic stress. It seems that a very high oxidoreductive potential in grapevine tissues prior to occurrence of osmotic stress is essential for maintaining proper homeostasis of oxidation and reduction reactions.
This study evaluated the effect of Pseudomonas strains and arbuscular mycorrhiza fungi (AMF) in enhancing strawberry yield and phenolic and antioxidant capacity on a phosphorus (P) deficient calcareous soil. The experiments were conducted in three replicates with six treatments (four Pseudomonas strains, AMF and control) and three rates of P-fertilizer (0, 75, 150 kg P ha–1). Application of higher phosphate rates decreased total antioxidant capacity, total phenolic and flavonols content, whereas AMF and Pseudomonas strains increased quality and P concentration of fruit. The use of AMF and Pseudomonas strains resulted in better quality when used along with 75 kg P ha–1. These results demonstrated that the rhizospheric microorganisms improved the quality of fruit, especially when they applied in combination with lower rates of chemical fertilizers. Therefore, application of these microorganisms in sustainable agriculture is recommended.
Sok z mieszaniny jabłek zawierającej 80% odmiany ‘Szampion’ (wysoka zawartość związków fenolowych i wysoka aktywność anty oksydacyjna) i 20% odmiany ‘Lobo’ (wysoka aktywność oksydazy polifenolowej) charakteryzował się w czasie przechowywania wyższą stabilnością fizyczną i biochemiczną w porównaniu z sokami jednorodnymi, otrzymywanymi z tych samych odmian jabłek. Sugeruje się, że przyczyną tych różnic jest, indukowany aktywnością oksydazy polifenolowej na etapie otrzymywania soku mieszanego, spadek zawartości kwasu chlorogenowego i epikatechiny. W czasie rocznego przechowywania soku mieszanego, w przeciwieństwie do soków jednorodnych przechowywanych przez 5 miesięcy, jego aktywność przeciwutleniająca pozostawała na tym samym poziomie, natomiast zmniejszenie zawartości związków fenolowych charakterystycznych dla jabłek było zauważalnie mniejsze i dotyczyło głównie kwasu chlorogenowego.
The object of experiments carried out in 2007 and 2008 were plants of lemon balm (Melissa officinalis L.) which were at that time in the 1st, 3rd and 4th year (2007) and in the 2nd, 4th and 5th year (2008) of growing. The soil from plots on which the plants were grown was studied as well. The yield of fresh and dry matter of the herbal raw material as well as the essential oil content in the raw material were determined. Furthermore, the soil phytotoxicity and phenolic compounds content in the soil were studied. Maximum yield of the fresh and dry weight of the herbal raw material were obtained in the 3rd and 4th year of plant cultivation and it was maintained on an unchanged level in the 4th and 5th year of growing. As the time of lemon balm growing was elongated, the increase of essential oil yield was observed. Phytotoxicity of soil occurred seasonally – in spring and in autumn and did not depend on the year of growing duration. On the other hand, the content of phenolic compounds in the soil increased gradually with the long-term cultivation. However, the phenolic compounds did not accumulate in such amount as to exert a negative effect on the plants.
The experiment determined the relationship between enzymatic darkening and the content of phenolic compounds in different parts of potato tubers. 14 cultivars grown at Plant Breeding and Acclimatization Institute were used in the study. The tubers were divided into 4 parts to be compared (bud-end, stem-end, vascular ring and core tissue). Percentage of phenolic compound content was determined in four parts of tubers as well as darkening of potato pulp after 30, 60, 180 and 240 min. The enzymatic darkening was measured by objective method (Minolta CR-300) and the subjective one. Percentage of phenolic compound contents was the highest in the stem-end (49 mg‧100 g⁻¹ FM). No significant differences were found in phenolic compound contents for particular parts of the tubers. However significant differences in enzymatic darkening were observed in the parts of tubers after 30, 60 and 180 min, as well as the close relationship between phenolic compound contents and enzymatic darkening intensity of particular tuber parts.
The aim of this research was to determine the influence of various forms, diverse doses, and methods of application of nitrogen fertilizers and foliar nutrition on the concentration of soluble sugars, ascorbic acid and phenolic compounds in cabbage. The three year (2005–2007) field experiment was carried out with ‘Galaxy’ F1 white cabbage. Two factors were examined: the type of N fertilizer ammonium sulphate and RSM (solution ammonium nitrate and urea 1 : 1), and method of N application (placement and top dressing – broadcasted with or without foliar nutrition). Climatic conditions considerably affect the concentration of compounds in cabbage. The highest concentration of soluble sugars was fund in cabbage receiving N as RSM in comparison to ammonium sulphate and with foliar nutrition treatment. In each year of the experiment plants fed RSM were characterized highest concentration of ascorbic acid. For means of year 2005–2007 foliar nutrition led to a marked decline in the concentration of ascorbic acid in cabbage. In 2005 and 2007 highest concentration of phenolic compounds was assessed in cabbage plants fed RSM. Cabbage plants fertilized 75% N broadcasted at planting of seedlings with foliar nutrition characterized the lowest concentration of phenolic compounds – means for 2005–2007.
The yield of an artichoke herb depended on number of harvests undertaken. Definitely higher yield of an air-dried herb was obtained from twofold (0.74 kgm2) and threefold (0.65 kg m 2) harvest in comparison to single one (0.46 kg m 2). The content of polypheno­ls acids in herb obtained from threefold harvest (in 1st decade of August, September and October) and from the twofold harvest (in 1st decade of September and October) was over 50% higher than that from the single harvest (1st decade of October). Content of flavonoids, depending on number of harvest, varied from 0.23% to 0.36% in the artichoke herb.
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