Abstract
Current-year needles were sampled regularly from an approximately 20-year-old natural stand of Pinus silvestris. Chloroplast thylakoids were isolated. The electron transport capacities of photosystem II + photosystem I, as well as of the partial photoreactions, were measured. The amounts and the fatty acid compositions of monogalactosyldiglyceride, digalactosyldiglyceride, and sulfolipid of the thylakoids were analyzed. The fatty acid composition of the phospholipids (total) was also determined.
There was a 2-fold increase in the content of the galactolipids and the sulfolipid in the thylakoid preparations during the autumn. Except for monogalactosyldiglyceride that decreased in content during early winter, the content of the other two lipids remained high during the winter, until spring when their content fell toward a low summer level. The ratio of monogalactosyldiglyceride to digalactosyldiglyceride was lower in thylakoids isolated from frosthardened (autumn, winter) than in those isolated from unhardened (summer) needles.
Only monogalactosyldiglyceride showed pronounced and significant seasonal variations in the molar ratio of unsaturated to saturated fatty acids. It was low in the winter, and it increased strongly during the spring. The highest ratio was observed in September, prior to the first night frosts, after which a steady decrease toward the low winter value occurred. This decrease is thought to be a reflection of membrane damages (photooxidation of membrane components, including polyunsaturated fatty acids), as earlier seen reflected in chlorophyll destruction, electron transport inhibition, and structural changes.
There was very good correlation between the seasonal variations in the capacity for electron transport from water to NADP and the level of unsaturation of monogalactosyldiglyceride (r = 0.93). It has been shown earlier that the winter inhibition of electron transport preferentially occurs at the lipophilic electron transport carrier plastoquinone and that the free miscibility of plastoquinone and monogalactosyldiglyceride is prevented in saturated monogalactosyldiglyceride. Therefore, it is hypothesized that the decreased level of unsaturation of monogalactosyldiglyceride reduces the mobility of plastoquinone in the thylakoids, resulting in an inhibition of the electron transport by way of plastoquinone.
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- Andersson B., Anderson J. M. Lateral heterogeneity in the distribution of chlorophyll-protein complexes of the thylakoid membranes of spinach chloroplasts. Biochim Biophys Acta. 1980 Dec 3;593(2):427–440. doi: 10.1016/0005-2728(80)90078-x. [DOI] [PubMed] [Google Scholar]
- Deyoe D. R. Glycerolipid and Fatty Acid Changes in Eastern White Pine Chloroplast Lamellae during the Onset of Winter. Plant Physiol. 1979 Dec;64(6):924–929. doi: 10.1104/pp.64.6.924. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Guillot-Salomon T., Tuquet C., De Lubac M., Hallais M. F., Signol M. Analyse comparative de l'ultrastructure et de la composition lipidique des chloroplastes de plantes d'ombre et de soleil. Cytobiologie. 1978 Aug;17(2):442–452. [PubMed] [Google Scholar]
- Harris P., James A. T. The effect of low temperatures on fatty acid biosynthesis in plants. Biochem J. 1969 Apr;112(3):325–330. doi: 10.1042/bj1120325. [DOI] [PMC free article] [PubMed] [Google Scholar]
- MORRISON W. R., SMITH L. M. PREPARATION OF FATTY ACID METHYL ESTERS AND DIMETHYLACETALS FROM LIPIDS WITH BORON FLUORIDE--METHANOL. J Lipid Res. 1964 Oct;5:600–608. [PubMed] [Google Scholar]
- Nichols B. W., Harris R. V., James A. T. The lipid metabolism of blue-green algae. Biochem Biophys Res Commun. 1965 Jul 26;20(3):256–262. doi: 10.1016/0006-291x(65)90356-6. [DOI] [PubMed] [Google Scholar]
- Rouser G., Kritchevsky G., Simon G., Nelson G. J. Quantitative analysis of brain and spinach leaf lipids employing silicic acid column chromatography and acetone for elution of glycolipids. Lipids. 1967 Jan;2(1):37–40. doi: 10.1007/BF02531998. [DOI] [PubMed] [Google Scholar]