Natural variation in tolerance to sub-zero temperatures among populations of Arabidopsis lyrata ssp. petraea.

BACKGROUND: Temperature is one of the most important abiotic factors limiting plant growth and productivity. Many plants exhibit cold acclimation to prepare for the likelihood of freezing as temperatures decrease towards 0 °C. The physiological mechanisms associated with enabling increased tolerance to sub-zero temperatures vary between species and genotypes. Geographically and climatically diverse populations of Arabidopsis lyrata ssp. petraea were examined for their ability to survive, maintain functional photosynthetic parameters and cellular electrolyte leakage integrity after being exposed to sub-zero temperatures. The duration of cold acclimation prior to sub-zero temperatures was also manipulated (2 and 14 days).

RESULTS: We found that there was significant natural variation in tolerances to sub-zero temperatures among populations of A. petraea. The origin of the population affected the acclimation response and survival after exposure to sub-zero temperatures. Cold acclimation of plants prior to sub-zero temperatures affected the maximum quantum efficiency of photosystem II (PSII) (Fv /Fm ) in that plants that were cold acclimated for longer periods had higher values of Fv /Fm as a result of sub-zero temperatures. The inner immature leaves were better able to recover Fv /Fm from sub-zero temperatures than mature outer leaves. The Irish population (Leitrim) acclimated faster, in terms of survival and electrolyte leakage than the Norwegian population (Helin).

CONCLUSION: The ability to survive, recover photosynthetic processes and cellular electrolyte leakage after exposure to sub-zero temperatures is highly dependent on the duration of cold acclimation.