Some environmental factors, including water availability, may influence seed
germination. This study investigated the germination of E. velutina seeds submitted to different
osmotic potentials and mobilization of reserves during water-stress. Scarified seeds were arranged
in paper rolls and soaked in solutions of Polyethylene Glycol (PEG) prepared in osmotic potentials
0.0, -0.2, -0.4, -0.6, and -0.8 MPa and kept into a seed germinator, at 25 °C, and 12/12 h photoperiod
(L/D), during 10 days. The percentage, mean time, mean speed, germination speed index; as well as
the germination uniformity coefficient were assessed. During germination process the total soluble
sugars, reducing sugars, soluble protein, and total amino acids were quantified in the cotyledon,
hypocotyl and radicle of soaked seeds and cotyledons of quiescent seeds (control). There was
influence of osmotic potential on E. velutina seed germination. The germination percentage remained
at high levels until -0.6 MPa and above this osmotic potential there has been no germination. The
mobilization of stored reserves of carbon and nitrogen in E. velutinaseeds was also influenced by
water-stress. There was sensitiveness between -0.2 and -0.6 MPa; however, the degradation and the
mobilization of reserves was slower when the osmotic potential decreased.