Analysis of Orderness of Lipids in the Plasma Membrane and Tonoplast Fractions of Beetroot

An analysis of the distribution of the order parameter of lipids in the plasma-membrane and tonoplast fractions isolated from beetroot (Beta vulgaris L.) was carried out. The packing density (order) of membrane lipids was assessed based on measurements of the generalized polarization (GP) of Laurdan fluorescence. From two to four components were revealed in the distribution of GP values of plasma membrane fractions in zones of sucrose density gradient, and from two to six components were detected in the distribution of tonoplast GP fractions. According to the analysis of the distribution of the lipid ordering parameter, raft structures in the plasma membrane can be present in zones of 15 and 25% (bottom) sucrose, and in the tonoplast, in zones of 15 and 60% sucrose. The results obtained are consistent with the results of studying the lipid composition of the corresponding zones of the plasma membrane and tonoplast fractions.