Abstract:Mosses attracted more and more attention in the fields of molecular biology and stress physiology as mode plants. Researches on osmolytes and antioxidant enzymes of mosses under stress conditions will provide base materials to understand their physiological mechanisms to stress conditions. Hypnum fertile Sendtn. a moss species with a wide range of habitats and geographical distributions, was treated under 5, 40 and 60℃ for 0.5, 1, 2, 4, 6 and 8 h, respectively. The contents of soluble sugar, free proline, MDA and the activities of SOD, POD, and CAT were determined. The main results were: 1) the content of soluble sugar increased with stress time under 5℃, while first increased and then decreased under 40 and 60℃; 2) the contents of free proline and MDA both increased with stress time under 5, 40 and 60℃；3) the activity of CAT gradually increased under 5℃, first increased and then decreased under 40℃, while declined rapidly and completely lost activity after 6h treatment under 60℃; 4) the activity of SOD decreased with the time under 5℃, while first increased and then declined under 40 and 60℃; 5) the activity of POD both increased under 5 and 40℃, while first increased and then decreased under 60℃. Our conclusions were: 1) the damage of low temperature (5℃) to H.fertile is less than high temperature (40 and 60℃), namely H.fertile is suitable to distribute in lower temperature environments; 2) Free proline enhanced the tolerance of H.fertile to both lower and higher temperature stresses; 3) POD and CAT might play a role in the adaptation of H.fertile to lower temperature environment, while SOD to higher temperature environment.