Drought stress in seedlings: Lipid metabolism and Lipid peroxidation during recovery from drought in Lotus comiculatrus and Cerastium fontanum

Abstract

Seedling survival of drought during the first days following germination can be one of the most critical factors in successful establishment of the species. Seventy‐two hour old seedlings of Cerastium fontanum Baumg. and Lotus corniculatus L. were exposed to severe desiccation for 36 h and the recovery of the whole plants monitored over the subsequent 17 days. The analysis exposed the very different responses to water stress in the two species. The effects of water stress on the less drought tolerant L. corniculatus within the first 5 to 10 days after drought treatment included a 2‐fold larger loss in dry weight than in C. fontanum and a 2‐fold rise in lipid peroxidation (thiobarbituric acid‐reactive substances), in triacylglycerols and in free fatty acids. The ratio of mo‐nogalactosyl diacylglycerols/digalactosyl diacylglycerols (MGDG/DGDG) declined 3‐fold, while the proportion of MGDG was some 12‐fold lower. In contrast, in the relatively drought‐tolerant seedlings of C. fontanum no changes of this order were recorded in the days immediately following rehydration. The relationship between these changes in lipid metabolism, lipid peroxidation and drought‐induced damage in terms of growth is discussed in the context of seedling recovery and survival in the two species.