Abstract
Seasonal changes of lipid compositions in leaves of Natsudaidai 'Kawanonatsudaidai' (Citrus natsudaidai Hayata), a cold-sensitive species, and Yuzu 'Tadanishiki' (Citrus junos sieb. ex Tanaka), a frost-hardy species, were studied.
Glycolipids were mainly monogalactosyl diglyceride (MGDG) and digalactosyl diglyceride (DGDG), whereas the phospholipids were mainly phosphatidylcholine (PC), phosphatidylethanolamine (PE) and phosphatidylglycerol (PG). The main fatty acids in both lipids were palmitic acid (16 : 0), stearic acid (18 : 0), oleic acid (18 : 1), linoleic acid (18 : 2), and linolenic acid (18 : 3). PG contained trans-Δ3-hexadecenic acid (16 : 1).
PG was less unsaturated phospholipid than were PC and PE, whereas MGDG was more unsaturated than was DGDG.
Phospholipid levels (PC and PE) were high during winter in Natsudaidai and Yuzu. The 18 : 3 and 18 : 2 compositions in glycolipid (MGDG) increased and the double bond index (D. B. I.) attained a high level in winter. The 18 : 2 and 18 : 3 compositions in phospholipid (PC) increased and D. B. I. approached maximum during winter. Phospholipid contents and 18 : 3 compositions in glycolipid (MGDG) and phospholipid (PC) were higher in Yuzu than they were in Natsudaidai.
Sterol contents increased during winter concomitantly with phospholipid and β-sitosterol; the sterols were higher in Yuzu than in Natsudaidai.
