Dormancy-breaking and salinity/water stress effects on seed germination of Atlas cypress, an endemic and threatened coniferous species in Morocco

Abstract

Atlas cypress (Cupressus atlantica Gaussen) is an endemic coniferous medicinal species geographically restricted to the N’Fis valley river in the High Atlas Mountains in South-Western Morocco. Eight dormancy-breaking treatments, 5 NaCl concentrations, and 5 water potentials were tested on the germination of Altas cypress seeds that had been stored in a cold room for 5 years after collecting from Aghbar population. Hand  scarification, gibberellic acid and hot water increased the seed germination percentage (up to 75%), and mechanical scarification and gibberellic acid (1000, 2000 ppm) induced a faster speed germination. Soaking in sulfuric acid (10%) did not improve the seed germination of C. atlantica. In addition, salinity higher than 160 mM NaCl and water potential below -0.53 MPa drastically reduced seed  germination.

Key words: Cupressus atlantica, seeds dormancy, scarified seeds, NaCl, water potential.