Effects of dehydration and rehydration on the polar lipid and fatty acid composition of Ramonda species

Endemic Balkan species Ramonda serbica and Ramonda nathaliae (Gesneriaceae) are rare resurrection flowering plants, known to withstand repeated cycles of desiccation–rehydration in their natural habitat. Analysis of their leaf lipids and fatty acids revealed a rather small amount of total lipids (15.8 mg/g dry weight in R. serbica and 19.5 in R. nathaliae) and galactolipids, particularly the monogalactosyl-diacylglycerol, considerably poorer in linolenic acid in comparison to other flowering plants (55% for R. nathaliae and 64% for R. serbica). Severe desiccation leads to a drastic loss in total lipids (76% in R. serbica and 71.5% in R. nathaliae), especially in monogalactosyl-diacylglycerol, but the recovery is extremely rapid and thorough upon the rewetting. A shift towards the more saturated oleic and linoleic acids in galactolipids occurs at a different time and to a different degree in the two species, and it is not evenly repaired. Ramonda serbica, known to be somewhat less resistant, shows a wider range of lipid changes.