Literature data about qualitative composition of the classes of polar lipids constituting plant cell membranes are discussed. A diversity of classes of phospho-, glyco-, and other lipids and hydrophobic compounds lacking acyl groups are given. Fatty acid composition of polar lipids, composition of amino alcohols as components of glycosphingolipids, and oxyacids abundant in cerebrosides are considered. A key role of saturated fatty acids in the creation of an optimal physical state of membranes necessary for their normal operation is emphasized. A necessity and feasibility of construction of 3D models of biomembranes is stressed. A logic approach is proposed to a better understanding of the role of qualitative diversity of lipid composition in membrane organization. Materials showing a possibility of chemical and biological transformation of lipids in plants are cited. Several issues of membrane structure, including microdomains, remodeling of bilayer, and vesicular traffic are addressed.

Literary data on very long-chain fatty acids (VLCFAs) that are present in polar lipids of the plant cell membranes are discussed. Large amounts of VLCFA are found in polar lipids of some cellular organelles as well as in nonextractable lipids from diverse plant objects, where the influence of surface lipids on the relative content of these FAs is excluded. In some plants, the VLCFA fraction in membrane lipids increases under several kinds of stress. Amounts and diversity of VLCFAs are lower in flowering plants as compared with the representatives of more ancient taxons—gymnosperms, ferns, and marine algae. Presence of VLCFAs in the composition of annular lipids of the cell membranes is assumed. Biosynthesis of VLCFAs, enzymes involved in the process, and encoding genes are discussed.

Fatty acid (FA) composition of lipids from leaves and differentiated fleshy strobila tissues and sporangia with spores of Cycas ( Cycas revoluta Thumb.) after their step quantitative extraction from plant material was investigated. Quantitative content and qualitative composition of FAs of extractable and nonextractable leaf lipids were determined. It was established that flesh lipids of sporophylls are characterized by a high saturation level and contain a considerable proportion of saturated FAs with the usual chain length (C 12 –C 18 , 53–57%). At the same time, total amount of etherified FAs with a very long chain in lipids not extractable by the method of Zhukov and Vereshchagin exceeds several times that found in extractable lipids (~15 and ~4%, respectively). Neutral lipids of Cycas spores were represented by triacylglycerols, the lower-alkyl esters of FAs, free FAs, and sterol esters.

The fatty acid (FA) composition of total extractable and non extractable with chloroform lipids of C. revoluta pollen was determined. Among other minor FAs, unusual Δ5 polymethylene-interrupted FA, Δ5, 11-octadecadienoic acid was found. This FA was found in the seed lipids of C. revoluta earlier, but it was discovered for the first time in pollen lipids.

The content of palmitic acid (PA) in the fractions of plant lipids of different polarity were investigated. The following relationship was revealed: when polarity of lipid fraction rose, the content of PA in total fatty acids of this fraction increased. It was shown that in a number of consecutive extracts of total lipids isolated from plant tissue with the same solvent each next extract containing more tightly bound lipids carries more PA. Predominance of this fatty acid within high-polar lipids that may be compared to annular lipids and are indispensable for operation of numerous enzymatic systems are discussed. A considerable quantity of PA was shown in wheat mitochondrial membranes; under cold stress, its level rose even higher. Among phospholipids, the greatest content of PA is usually associated with phosphatidyl inositols, while that among glycolipids is with sulfoquinovosyl diacylglycerols.

At three stages of fruit ripening of three euonymus species (Euonymus sp.), growth parameters, the development of morphologo-anatomical structure, and the accumulation of neutral acylglycerols (NAG) of fatty acids were studied. It was established that, in all species studied, in the cells of endosperm and cotyledons, as well as in arillus cells, small oleosomes of similar size were formed, whereas in Euonymus europaeus and E. maximowiczianus large oleosomes differing in their sizes also appeared. Independently of fruit age, dry weight of seeds exceeded that of arils by several times. At the determination of separate NAG classes: TAG (1,2,3-triacyl-sn-glycerols) and acDAG (3-acetyl-1,2-diacyl-sn-glycerols), it was shown that the absolute content of acDAG in seeds was 1.5 orders of magnitude higher than that of TAG; in contrast, in arils TAG were much more abundant than acDAG. Euonymus species differed markedly in the growth pattern and NAG accumulation in seeds and arils.

Small amounts of a mixture of fatty acid lower-alkyl esters (FALAEs) were obtained from chloroform extracts of the fruit arils and seeds of four euonymus species (Euonymus sp., Celastraceae). The FALAEs were the products of biosyntheses in the cell rather than experimental artifacts. By using GC-MS, this mixture was shown to contain a total of 19 individual FALAE species comprising four separate fractions, viz. methyl (FAMEs), ethyl (FAEEs), n-propyl, and n-butyl FA esters. Fruit FALAEs included mainly FAEEs and, to a lesser extent, FAMEs, while the n-propyl and n-butyl FA esters, which occurred less frequently, were found here for the first time as the plant products. The FALAE acid components included C14-C18 saturated, mono-, di-, and trienoic FAs with the predominance of ubiquitous linoleic, oleic, palmitic, and, in some cases, also α-linolenic acid. The indices of qualitative and quantitative composition of separate FALAE fractions varied considerably depending on the plant species, fruit part (aril or seed), and the extent of fruit maturity. It can be supposed that, in some euonymus species, FAMEs and FAEEs are formed at the expense of the same FA pool characteristic for a given species. As a whole, euonymus FALAEs and triacylglycerols seem to be synthesized from different FA pools. Discussed is the physiological significance of FALAE biosynthesis in plant metabolism, possible pathways of this biosynthesis, as well as the perspectives of further investigations of FALAEs of plant origin.

The concentration of dry matter and the content of esterified fatty acids in total lipids of roots and etiolated shoots of 3- to 10-day-old seedlings of wheat (Triticum aestivum L.) infected with Bipolaris sorokiniana (Sacc.) Schoemaker, the agent of helminthosporic root rot, were determined in the course of germination. At the onset of germination, fungal infection caused a considerable increase in the dry matter concentration in both roots and shoots due to the enhanced mobilization of seed reserves. However, after the 7th day of germination, dry matter concentration fell below the level of noninfected control seedlings as a result of infection. The content of total lipids rose immediately after infection and always exceeded the control index up to the end of germination, in spite of a continuous decrease in this index in both control and infected seedling. It is concluded that an increase in the content of cellular lipids is a characteristic response of both shoots and roots to the root rot infection of wheat seedlings.