The Role of Neutral Lipids of Larix cajanderi Mayr in Adaptation to the Cold Climate of the Cryolithozone

The mechanisms underlying the development of extreme cold tolerance in woody plants involving lipids – including neutral lipids (NLs) and their fatty acids (FAs) in the adaptation to low sub-zero temperatures (down to −60°C) characteristic of the cryolithozone remain poorly understood. To elucidate the role of NLs in such adaptation, we investigated the patterns of seasonal changes in their composition and content in the shoots of Cajander larch (Larix cajanderi Mayr) growing in the natural conditions of Yakutia. Among NL, the focus was on 1,2,3-triacyl-sn-glycerols (TAG) as the dominant storage lipids, as well as sterol esters (SE) and waxes. Analysis of NL and their FAs was performed using HPTLC and GC-MS methods. It was found that in the annual cycle of L. cajanderi, the maximum accumulation of total lipids (TL) up to 83.2 mg/g dry weight and TAG up to 26.1% of TLs in larch shoots occurs during the fall-winter period, whereas the wax content increases to 6.9% of TLs during the summer period. During the fall-winter period, the proportion of unsaturated fatty acids (UFA) in the TAG composition increased to 69% of sum. The seasonal reorganization of the composition and content of L. cajanderi, involving the accumulation of storage lipids (TAG) and an increase in the degree of FA unsaturation, is likely an important link in the biochemical mechanisms ensuring the exceptionally high frost resistance of larch as it adapts to the cold climate and permafrost conditions of Yakutia.