Fig. 4

Comparative analyses of lipids in extracts from the wild type and tt mutants. a The heatmaps were constructed from the average normalized intensity values of lipids shown to be significantly different between NEs and MEs by PCA analyses. The color intensity scale is on the left-hand side of the heatmaps. Different lipid subclasses are labeled with different colors in the legend positioned on the right-hand side. FA, fatty acyls; GL, glycerolipids; GP, glycerophospholipids; SP, sphingolipids; ST, sterol lipids; PR, prenol lipids. b Confocal microscopic analysis of TiO₂ NP-treated wild-type seedlings reveals membrane damage. Z-stack projections (10 slices, 25 µM thick) of SYTOX green-stained cotyledon of a 4-day-old seedling treated with 1.9 mM TiO₂ NP for 4 h is shown. Green fluorescence signifies membrane permeabilization that allows the dye to enter the cell, bind DNA and emit at 510–560 nm when excited by a wavelength of 488 nm