Taxonomic Significance of Surface Lipids of Plants

Abstract

WHILE investigating the composition of surface lipids of plants, we have observed that the chemical composition of the lipid appears to be characteristic of the species of plant. The lipids were extracted from leaves by immersing them for 10 sec. in ether. According to Martin et al. ¹, and in harmony with our own findings, this treatment does not extract lipids from within the leaf. After removal of the solvent, the residues were chromatographed on thin films of silica supported on glass plates. Three solvents were used for the elution : benzene, benzene containing 5 per cent methanol, and benzene containing 10 per cent methanol. The positions of the components were revealed by spraying separate plates with two reagents : chloroform saturated with antimony trichloride, and saturated aqueous ferric chloride followed immediately by 0.1 molar sodium molybdate. Both series of plates were heated to 200° C. for 10 min. for full development of the colour. If the plates which were to be sprayed with antimony trichloride were first heated to 200° C. for 10 min. and sprayed while hot, the components showed a large range of colours. Subsequent examination in ultra-violet light showed a less-extensive range of fluorescent colours. Specimen chromatograms in one solvent are shown in Fig. 1.