Ellagic acid (EA) is a natural antioxidant, belonging to the group of polyphenolic compounds. It displays a broad spectrum of pro-health effects, ranging from the prevention of cancer to antiviral properties. It is present in many fruit from the rose family (Rosaceae): strawberries, raspberries, blackberries and walnuts as well as cranberries and grapes. The available literature states that the fruit of roses, in addition to their aesthetic and functional applications, also show therapeutic properties, which, among other things, are associated with a high content of polyphenols, including ellagic acid derivatives. The aim of this research was to determine the differences in the content of free ellagic acid in the fruit of selected rose species. The test material consisted of freeze-dried sublimation and ground fruit from the following species of roses: R. canina, R. moyesii, R. pendulina. The fruit was separated into two fractions: flesh and seeds. Quantitative analysis of free ellagic acid was carried out by spectrofluorimetry. The free EA was present both in the flesh and in the seeds of the studied species of roses. Its content in the mentioned fractions varied depending on the species. The flesh of R. pendulina was characterised by the highest level of EA in free form (247.72 μg·g–1 of dry weight). The seeds of R. moyesii proved to be the most abundant in free EA (105.69 μg·g–1 of dry weight).
The studies were carried out in order to estimate differences in the physiological state between triticale and maize plants subjected to drought stress followed by rehydration. The physiological state of the plants was evaluated by measurements of leaf water potential, net photosynthesis, transpiration and stomatal conductance. Spectrofluorimetric methods for the study of blue, green and red fluorescence were applied. We observed that the soil drought induced a greater water loss in triticale leaves than in maize and consequently caused greater injusies to the photosynthetic appasatus. Moreover, triticale plant recovery was slower than in maize plants during the rehydration phase. The effect was probably connected with the higher functional and structural disorganisation of the photo synthetic appasatus observed during drought stress in triticale. Water stress is responsible for damages to photo - system PS II. The worst light utilisation in photosynthetic light conversion was recorded as an increase in the intensity of red fluorescence. Drought stress induced a strong increase in the intensity of blue and green fluorescence in the studied species and it was still high in maize plants during the first day of rehydration. Increase in the intensity of blue and green fluorescence in maize seems to be the effect of the photoprotection mechanism which prevents damage to PS II through utilisation of excess energy.
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