BACKGROUND AND AIMS: Differential responses of closely related species to 
submergence can provide insight into the evolution and mechanisms of submergence 
tolerance. Several traits of two wetland species from habitats with contrasting 
flooding regimes, Rorippa amphibia and Rorippa sylvestris, as well as F(1) 
hybrid Rorippa × anceps were analysed to unravel mechanisms underlying 
submergence tolerance.
METHODS: In the first submergence experiment (lasting 20 d) we analysed biomass, 
stem elongation and carbohydrate content. In the second submergence experiment 
(lasting 3 months) we analysed survival and the effect of re-establishment of 
air contact on biomass and carbohydrate content. In a separate experiment we 
analysed expression of two carbohydrate catabolism genes, ADH1 and SUS1, upon 
re-establishment of air contact following submergence.
KEY RESULTS: All plants had low mortality even after 3 months of submergence. 
Rorippa sylvestris was characterized by 100 % survival and higher carbohydrate 
levels coupled with lower ADH1 gene expression as well as reduced growth 
compared with R. amphibia. Rorippa amphibia and the hybrid elongated their stems 
but this did not pay-off in higher survival when plants remained submerged. Only 
R. amphibia and the hybrid benefited in terms of increased biomass and 
carbohydrate accumulation upon re-establishing air contact.
CONCLUSIONS: Results demonstrate contrasting 'escape' and 'quiescence' 
strategies between Rorippa species. Being a close relative of arabidopsis, 
Rorippa is an excellent model for future studies on the molecular mechanism(s) 
controlling these strategies.