EFFECTS OF FREEZE-THAW CYCLES ON SEED GERMINATION AND SEEDLING GROWTH OF H O RD EU M JUBATUM AND FESTUCA ELATA IN NORTHEAST OF CHINA

摘要

In order to clarify the effect of soil freeze-thaw cycle (FTC) on seed germination and seedling growth of northern herbaceous plants in seasonal permafrost regions, Horde-um -ubatum and Festuca (lata were used as the experimental grass species. Simulation experiments were used in this test, and different FTC temperatures (-9 -4 , -4 -4 , -4 ,- 4 ) and FTC time (1 d, 3 d, 5 d) were set. We measured seed germination percentage, germination time and seedling growth index. The results showed that the pre-freezing and thawing treatment at -9-40C was beneficial to seed germination of H. j-ubatum and F. d a ta , and the seed germination percentage and time were significantly higher than those of the control, and the seedling growth rate was much faster. Although seedling growth of the two grass species under the FTC treatment of -40C was higher than that of the control in early stage, seedling growth was sluggish in later stage, and little seedlings were even lower than that of the control. The results showed that FTC time and temperature had synergistic effects on seed germination and seedling growth, and the appropriate FTC time and temperature could im prove seed germination and seedling growth parameters in northeast of China.