Storage roots of `Beauregard' and `Centennial' were used to identify varietal differences in fatty acid composition in plasmalemma lipids during storage conditions. Total plasmalemma fatty acid composition of glycolipids and phospholipids in storage roots of `Beauregard' and `Centennial' did not differ. The fatty acid composition of MGDG and DGDG in storage root plasmalemma was >50% unsaturated fatty acids in `Beauregard'. The high percentage of 18:2 (65.44%) fatty acid compared to `Centennial' (19.70%) and 79.35% total unsaturated fatty acid content in MGDG may contribute to low temperature tolerance in `Beauregard'. The higher percentages of 16:1 and 22:1 fatty acids in `Centennial' compared to `Beauregard' contributed to MGDG fatty acid unsaturation. However, these fatty acids have not been related to chilling tolerance.
Arambage Abesinghe and James O. Garner
Bruce D. Whitaker
Altered metabolism of membrane lipids has been proposed as a mechanism for the beneficial effects of postharvest calcium treatment on apple quality. A previous study showed that after transfer of apples stored 6 months at 0C to 20C, calcium-treated fruit exhibited slower loss of galactolipid and altered levels of sterol conjugates. The present study of lipids in “control” fruit was conducted as a prelude to further in-depth analyses of the effects of postharvest calcium and heat treatments on lipid metabolism in apples during and after cold storage. Neutral lipid, glycolipid (GL), and phospholipid (PL) fractions were obtained by column chromatography followed by TLC separation of GL and PL classes. The major GL were steryl glycosides (SG), acylated steryl glycosides (ASG), cerebrosides (CB), and mono- and digalactosyl diacylglycerols. Phosphatidylcholine (PC) > P-ethanolamine (PE) > P-irositol (PI) were the major PL. The fatty acids of PC and PE were quite similar, whereas those of PI were more saturated. CB included only 2-hydroxy fatty acids. Among the steryl lipids, free sterols > SG > ASG, with beta-sitosterol >90% of the total sterol in each.
Shiow Y. Wang and Gene J. Galletta
The effect of silicon (Si) foliar applications on metabolic changes and powdery mildew infection in strawberry plants were determined. Silicon was used in the forms of potassium (K) and sodium (Na) salts. Foliar sprays containing 0, 250, 500, 750, and 1000 ppm of Si were applied. Strawberry plants showed no difference in response to the K or Na salts of Si during the seven weeks of experimental period. Plants treated with potassium and sodium silicate showed reduced severity of powdery mildew, increased chlorophyll content, and increased plant growth. Potassium and sodium silicate treatments also induced metabolic changes such as an increase in citric acid and malic acid levels, and a decrease in fructose, glucose, sucrose, and myoinositol content. The treated tissues also had higher ratios of (18:2 + 18:3)/18:1 in glycolipids and phospholipids and elevated amounts of membrane lipids in leaves and petioles. These results suggest that Si has beneficial effects on strawberry plants and may serve as an alternative to fungicides for controlling powdery mildew.
Aneela Nijabat, Adam Bolton, Muhammad Mahmood-ur-Rehman, Adeel Ijaz Shah, Rameez Hussain, Naima Huma Naveed, Aamir Ali, and Philipp Simon
membrane stability and membrane stabilizing factors such as osmolyte concentration (proline) and saturated structural lipids (phospholipids and glycolipids) to better understand the heat-tolerance mechanism in carrot germplasm. Table 3. Descriptive
Cristina Pisani, Mark A. Ritenour, Ed Stover, Anne Plotto, Rocco Alessandro, David N. Kuhn, and Raymond J. Schnell
acids composition of avocado during harvesting time and post-harvesting ripening period Food Chem. 86 79 83 Pacetti, D. Boselli, E. Lucci, P. Frega, N.G. 2007 Simultaneous analysis of glycolipids and phospholipids molecular species in avocado ( Persea