ARE THE FATTY ACIDS INVOLVED IN FROST TOLERANCE OF WINTER RAPE PLANTS ?

When rape plants were transferred from favourable temperature conditions / 25°C/20°C day/night temperature/ to 5°C the frost resistance of the leaves was increased whereas the frost tolerance of the roots remained unaffected, thus permitting an analysis of the changes in lipid and fatty acid composition as related to functioning of the plant at low temperature alone /roots/ and as related to adaptation to freezing and functioning at low temperature as well /leaves/. Transfer of the plants to 5°C led to an increase in the content of linolenic acid in roots and leaves, but this increase was most evident in the phosphatidyl choline and ethanolamine fractions of the leaves and in the neutral lipids and in the fraction of an unidentified phospholipid from the roots.
It was concluded that a general and non-specific increase in linolenic acid content contributed to functioning of the rape plants at low temperature and that parallel but minor increases in linolenic acid content of digalactosyl digliceride, phosphatidyl inositol and the unknown phospholipid in roots and leaves upon transfer of the plants to 5°C could only contribute to low temperature functioning in specific membrane enzyme locations.
Adaptation of the leaves to low-temperature functioning and to freezing condition was correlated with an increase in content of phosphatidyl choline and ethanolamine, predominantly esterified with linolenic acid because the content of these lipids and its linolenic acid conjugate increased in the leaf tissue upon transfer of the plants to 5°C.

Symposium on Winterhardiness in Woody Perennials

G. Smolenska, P.J.C. Kuiper

https://doi.org/10.17660/ActaHortic.1978.81.23