Induction of Biosynthesis Antioxidant Molecules in Young Barley Plants by Trioxygen

Physiological and Morphological Implications of Using Composts with Different Compositions in the Production of Cucumber Seedlings

Compost has a broad application in terms of the improvement of the soil properties. This research work was conducted to present the molecular implications of using compost obtained from different substrates to improve soil parameters for cucumber seedlings cultivation. In the experiment, the following compost mixtures were used: sewage sludge (80%) + sawdust (20%); sewage sludge (40%) + sawdust (10%) + biodegradable garden and park waste (50%); biodegradable garden and park waste (90%) + sawdust (10%); sewage sludge (80%) + sawdust (20%) + Eisenia fetida; sewage sludge (40%) + sawdust (10%) + biodegradable garden and park waste (50%) + Eisenia fetida; biodegradable garden and park waste (90%) + sawdust (10%) + Eisenia fetida. The final substrate compositions consisted of compost mixtures and deacidified peat(O) (pH 6.97; Corg content-55%, N content-2.3%), serving as a structural additive, in different mass ratios (mass %). The produced plants underwent biometric and physiological measurements as well as enzymatic analyses of stress markers. Based on the conducted studies, it has been found that the substrate productivity depends not only on the content of nutrient components but also on their structure, which is moderated by the proportion of peat in the substrate. The most effective and promising substrate for cucumber seedling production was variant 2 (I), which consisted of 25% compost from sewage sludge (40%) + sawdust (10%) + biodegradable garden and park waste (50%) and 75% deacidified peat. Despite the richness of the other substrates, inferior parameters of the produced seedlings were observed. The analysis of the enzymatic activity of stress markers showed that these substrates caused stress in the plants produced. The study's results showed that this stress was caused by the presence of Eisenia fetida, which damaged the developing root system of plants in the limited volume of substrate (production containers). The adverse influence of Eisenia fetida on the plants produced could possibly be eliminated by thermal treatment of the compost, although this could lead to significant changes in composition.

Variability of Properties Modulating the Biosynthesis of Biologically Active Compounds in Young Barley Treated with Ozonated Water

This paper presents the effects of irrigating barley plants with different type of water solutions saturated with gaseous ozone generated from atmospheric air. The study investigated the effects of the applied types of water on the modulation of the biosynthesis of selected bioactive compounds (content of total polyphenols, small molecule antioxidants, vitamin C) in the produced plant material. A number of transformations of reactive oxygen species (ROS) and nitrogen compounds have also been postulated; these are observed during the saturation of water with gaseous O₃ and 30 min after the end of the process. It was shown that after the process of water saturation with gaseous O₃, the gas later is converted to compounds with high oxidative potential and good stability; these, in turn, lead to the oxidation of oxidates generated from atmospheric nitrogen into nitrates, which exhibit fertilising properties. Thirty minutes after the process of H₂O saturation with gaseous O₃ was completed, the tests showed the highest concentrations of nitrates and the relatively high oxidative potential of the solution originating from H₂O₂ with a low concentration of the dissolved O₃. This solution exhibited the highest activity modulating the biosynthesis of polyphenols, small molecule antioxidants and vitamin C in young barley plants. The resulting differences were significant, and they were reflected by 15% higher total polyphenol content, 35% higher antioxidative potential and 57% greater content of vitamin C compared to the control specimens (plants treated with fresh H₂O).

The Modification of Substrate in the Soilless Cultivation of Raspberries (Rubus Idaeus L.) as a Factor Stimulating the Biosynthesis of Selected Bioactive Compounds in Fruits

Raspberry fruits are a valuable source of bioactive compounds. The study used the modification of the substrate (coconut fibre), consisting of the use of various organic and mineral additives, in the soilless cultivation of raspberries. The additives influenced the biosynthesis of bioactive compounds in the raspberry fruits by modifying the sorption properties and the abundance of the substrate. The influence of the additives on the content of polyphenols was determined as well as their profile (UPLC-MS), antioxidant potential (ABTS), vitamin C content, and the activity of selected enzymes that are markers of stress and resistance to abiotic factors. In the study, a significant effect of these additives was observed on the biosynthesis of polyphenols in raspberry fruit. The highest increase in the content of these compounds in relation to the control sample (substrate-100% coconut fibre), namely 37.7%, was recorded in the case of fruit produced on coconut substrate enriched with sheep wool. These fruits were also characterised by a significantly different profile of these compounds. These changes were caused by readily available ammonium nitrogen and free amino acids in the decomposition of proteins contained in the sheep wool. This was confirmed by the recorded content of chlorophyll SPAD in the plant leaves and the activity of selected enzymes, which proves a low level of stress and good condition of the plants.