Effect of dormancy relieving compounds on the seed germination of non-dormant Allenrolfea occidentalis under salinity stress

Allenrolfea occidentalis (Chenopodiaceae) is a highly salt tolerant plant species that is widely distributed in inland salt marshes and salt playas of the western United States. We investigated the influence of dormancy-relieving compounds (fusicoccin, ethephon, nitrate and thiourea) in alleviating salinity stress on the seed germination of A. occidentalis. Seed germination decreased with an increase in salinity and no seed germinated at 800 mM NaCl. Fusicoccin (5 mu M), ethephon (10 mM) and nitrogenous compounds (20 mM nitrate and 10 mM thiourea) were able to counteract the inhibition produced by salinity treatments. All dormancy relieving compounds significantly (P < 0.0001) promoted germination at all salinity concentations. Fusicoccin completely reversed the inhibitory effects of salinity on seed germination of A. occidentalis. Ethephon application significantly promoted germination at all salinities. Nitrate and thiourea were relatively less effective in alleviating the effects of high salinity on germination. (C) 1998 Annals of Botany Company.