Effects of seed vernalisation and photoperiod on flowering induction in the halophyte Thellungiella halophila

Abstract

Salt cress, Thellungiella halophila, is a late-flowering, halophytic plant that requires a prolonged period of vernalisation to flower. This poorly defined vernalisation requirement restricts the use of T. halophila as a model plant for the study of salt-stress tolerance. To facilitate research on T. halophila, the present study quantified the effects of seed vernalisation and photoperiod on its flowering. Imbibed seeds of T. halophila responded to a cold treatment (4°C), and flowering was optimal after 30 days of seed vernalisation. A longer vernalisation period shortened the time until the first flower appeared, increased the number of flowers and reduced expression of ThFLC (a repressor of flowering). Plants growing from seed that had been vernalised for 30 days did not flower when daylength was <9 h, and daylengths >9 h promoted flowering. Therefore, like for many plants in this clade of the Brassicaceae, vernalisation requirement and long-day response are features of T. halophila. These results will facilitate the use T. halophila as a model plant for the study of abiotic stress.