Search Results (2)

This article represents the first consideration of the peculiarities of the fatty acid (FAs) composition and structure of storage triacylglycerols (TAGs) of the relict plant Lunaria rediviva L. The composition of storage TAGs was found to comprise 21 individual FAs, with an unsaturated FA content of 96.8%. Additionally, monounsaturated acids with a very long chain (VLCFAs), specifically C20:1–C24:1, constituted over 60% of the total FAs. The ethylene bond position isomers of unsaturated FAs were accurately identified and the presence of unusual isomers, including 20:1$\Delta$13, 22:1$\Delta$15, and 24:1$\Delta$17 acids. Furthermore, the unusual minor 24:2$\Delta$15,18 acid was identified and characterised for the first time. The pathways of the mentioned VLCFA’s biosynthesis have been proposed. The distribution of FA acyls between the sn positions of triacylglycerols was found to be highly specific. Thus, VLCFAs exclusively acylate the $\alpha$ positions of the carbon atoms of the glycerol residue of the TAG molecule (sn-1 and sn-3 positions), while unsaturated C18 acids exclusively acylate the $\beta$-carbon atom (sn-2 position). The composition of the molecular species of TAGs was analysed using a calculation method based on the Vander Wal model and by RP-HPLC-ESI-MS. A significant discrepancy from the statistical model was observed, indicating a preference for the formation of symmetrical TAGs, such as sn-1,3-dierucoyl-2-oleoyl-glycerol and related molecular species. This observation led to the formulation of a hypothesis regarding the potential existence of at least two specialised enzyme isoforms involved in the biosynthesis of such TAGs via the Kennedy pathway, exhibiting unusual substrate specificity. Consequently, this plant can be regarded not only as a producer of unusual molecular types of triacylglycerols but also as a source of genetic material for the search of genes encoding the aforementioned enzymes with unusual substrate specificity. Full article

Long-term studies of plant populations provide valuable knowledge on the influence of various environmental factors on plant species. The status of edge-range species populations is especially important to be studied due to their higher vulnerability to extinction. This paper aimed to study the Lunaria rediviva population at the eastern border of its range (National Park “Smolny”, Republic of Mordovia, Russia). The study was carried out in 2013–2018. Assessment of the L. rediviva population was performed on the basis of individual parameters of plants (height of the individual, number of leaves per individual, number of inflorescences, flowers, fruits per one generative individual, and the fruit set), and density of individuals. Ontogenetic structure of the population was identified by distinguishing juvenile, mature vegetative, and reproductive individuals. The relationships between weather conditions (mean values of temperature, air moisture, wind strength, precipitation divided to three decades per month) and population parameters of L. rediviva were identified. Results showed changes in the ontogenetic structure of the population. The type of its population changed from vegetatively oriented to bimodal, with a decrease (R² = 0.686) in the proportion of mature vegetative individuals. We demonstrated a significant decline in some parameters of the L. rediviva reproduction. We found a significant negative correlation between the fruit set and the moisture at mid-July (r = −0.84, p < 0.05), and wind strength in late May (r = −0.83, p < 0.05) and early June (r = −0.83, p < 0.05). It was found that the number of both flowers and fruits per individual is significantly positively correlated with the precipitation in late April, and they negatively correlated with these parameters and the temperature in late July. We assume that the habitat shading negatively influences the L. rediviva population status. Full article