5 CONCLUSION
The genus Ionopsidium is adapted to hot and dry Mediterranean
conditions, whereas Cochlearia species largely prefer cold
habitats. However, all species evaluated in this study exhibited similar
and severe cold responses. Whether this similarity has resulted from an
evolutionary adaptation of a common ancestor of the two taxa or from
parallel evolution is unclear. However, the results of the present study
indicate that adapting to different stressors, such as salinity and
drought, also confers tolerance to cold, as all these stressors induce
osmotic challenges. From a present-day perspective, all taxa were
subjected to higher temperatures (Ionopsidium and C.
danica ), and eventually accelerated drought stress was adapted to at a
macroevolutionary scale with monocarpic growth. This pattern was more
widely distributed in the entire Brassicaceae family (e.g., tribe
Arabideae; Karl xxx), which, therefore, might indicate a more general
evolutionary path to temporarily escape from a changing environment
towards increasing temperature and drought. However, this also leads to
a pessimistic scenario for the long-term survival of various polycarpic
Central European Cochlearia species.