The effect of low oxygen concentration on the acyl-lipid and fatty-acid composition of the C4 plant Amaranthus paniculatus L.

Abstract

Acyl lipids and their constituent fatty acids were studied in leaves, chloroplasts and bundle-sheath strands of the C4 plant Amaranthus paniculatus L. grown under normal and 4%-oxygen-containing atmospheres. In all fractions the major lipids were found to be monogalactosyldiacylglycerol, digalactosyldiacylglycerol, sulphoquinovo-syldiacylglycerol and phosphatidylglycerol. Significant quantities of phosphatidylcholine and phosphatidylethanolamine were restricted to leaves and bundle-sheath strands. All lipids, except phosphatidylglycerol where 3-trans-hexadecenoic acid was also present, contained palmitic acid, stearic acid, oleic acid, linoleic acid and linolenic acid. On a chlorophyll basis and compared with whole leaves, the amounts of phosphatidylcholine and phosphatidylethanolamine in bundle-sheath strands were considerably reduced. Three weeks after the change from a normal to a 4% atmospheric O2 level, the galactolipid content, particularly in the bundlesheath strands, was enhanced. There were no significant differences in the degrees of saturationunsaturation of total acyl lipid for the plants grown in the low oxygen and normal atmospheres, although under 4% O2 the phosphatidylglycerol contained an increased proportion of 3-trans-hexadecenoic acid at the expense of palmitic acid.

A Shoot-Specific Hypoxic Response of Arabidopsis Sheds Light on the Role of the Phosphate-Responsive Transcription Factor PHOSPHATE STARVATION RESPONSE1

“…So far, only a few studies on the effect of low oxygen concentrations on the fatty acid or lipid compositions of leaves were reported. DGDG was suggested to accumulate in some plant species upon hypoxia, as shown for Amaranthus paniculatus (Knacker and Schaub, 1984). However, these plants were treated only with mild hypoxia (4% oxygen) for an extended period of 21 d.…”

Characterization of sources for southern African aerosols through fatty acid and trajectory analyses

“…Because fatty acid compositions of collected aerosols exhibit similar distributions as plant extracts [ Spangenberg et al , 1998; Lee et al , 1998], we believe that diurnal relationships are indicative of the expansion and contraction of the potential area of origin for the majority of collected aerosols, otherwise referred to as the source “footprint”. In studies of the source vegetation of vegetable oils and studies that examined fatty acids derived from C 4 plants, the ratio of C18:1 to C18:2 was less than 1 [ Spangenberg et al , 1998; Lee et al , 1998; Knacker and Schaub , 1984]. The aerosol fatty acid data was examined to determine whether a shift in plant biomass source based on the C18:1 to C18:2 ratio and photosynthetic pathway could be detected.…”

Membrane lipids are involved in plant response to oxygen deprivation

“…However, the total galactolipid contents were not severely affected and the phenotype of mgd2, mgd3, and mgd2/mdg3 mutants was similar to wild type under hypoxia stress. 7 In contrast, DGDG accumulated in Amaranthus paniculatus upon mild hypoxia (4% O 2 ) for an extended period of 21 d. 8 Except for the absolute contents, the molecular species of DGDG and MGDG as well as DGDG: MGDG ratio are also involved in hypoxia stress. For instance, the content of 34:6 (18:3, 16:3) MGDG slightly increased during submergence, accompanied by a decrease in 36:6 (18:3, 18:3) MGDG, while DGDG showed an inverse trend.…”