Abstract
Thellungiella halophila a highly salt tolerant species with high genetic and morphological similarity to classical model plant Arabidopsis thaliana has begun to serve a model for salt tolerant plants. Seeds from salt cress showed a deep dormancy at maturity. The level of dormancy decreased during after-ripening and cold stratification. After-ripend seeds of salt cress failed to germinate in dark and strong light while best seed germination was obtained in weak white light at 22 C. Light enhanced the sensitivity to GA4 in dark-imbibed salt cress seeds and strong light inhibited biosynthesis of GA4. The content of ABA was not affected by strong light implying that ABA signals is not the mechanism in inhibiting seed from germination by strong light. Temperature also affected seed germination at constant 20 C and variable 15/25 C regime are the best germination temperature. The seeds are sensitive to salt in comparison to some other halophytes, and showed similar dose response as Arabidopsis seeds to salt. However, salt cress remained dormant under salinity stress without loosing viability, while most Arabidopsis seed suffer heavy mortality under 400 mM NaCl after ten days.
