Extreme low temperature tolerance in woody plants

Area of Science:

• Plant physiology
• Cryobiology
• Biochemistry

Background:

• Boreal and arctic woody plants endure extreme low temperatures (ELT), with some surviving -60°C and laboratory exposure to -196°C.
• Acclimation involves significant biochemical shifts, including changes in carbohydrates, compatible solutes, membrane lipids, and proteins like dehydrins.

Purpose of the Study:

• To investigate the cellular and molecular mechanisms enabling plant survival at extreme low temperatures (ELT).
• To formulate hypotheses based on biophysical principles of membrane stress and strain.

Main Methods:

• Analysis of biochemical changes during acclimation, including proteomic and metabolomic studies.
• Consideration of biophysical mechanisms related to membrane stress and strain.

Main Results:

• Hypothesized that altered lipid composition stabilizes membranes above their phase transition temperature (-20 to -30°C), preventing injury.
• Hypothesized that high oligosaccharide concentrations promote cytoplasmic vitrification, preventing membrane interactions.
• Hypothesized that dehydrins bind membranes, aiding vitrification or acting sterically to prevent membrane-membrane contact.

Conclusions:

• Cellular adaptations involving lipid modification, oligosaccharide accumulation, and dehydrin activity are crucial for plant survival at ELT.
• These mechanisms collectively prevent membrane damage and maintain cellular integrity under extreme freezing conditions.