Effects of several environmental factors on seed germination of Macrotyloma uniflorum ‘Yazhou’

The effects of light, temperature, water, salinity, and burial depth on seed germination of Macrotyloma uniflorum ‘Yazhou’ was analyzed using petri-dish and pot-culture methods in this study. The results indicated that light, temperature, and their interaction significantly affected seed germination percentage (P < 0.05). Germination percentage and germination rate (1/t₅₀) first increased and then declined with increasing temperature. The seeds of M. uniflorum ‘Yazhou’ could germinate between 15～40 ℃, but the optimum germination temperature was 32.8 ℃ under light conditions and 32.4 ℃ under dark conditions. With increasing PEG and NaCl stress, the germination percentage and germination rate (1/t₅₀) gradually decreased, although germination rate (1/t₅₀) decreased faster than did germination percentage. The seeds of M. uniflorum ‘Yazhou’ could not germinate when the osmotic potential and NaCl concentration reached –1.2 MPa and 400 mmol·L^–1, respectively. The seedling percentage was highest at 1 cm burial depth, indicating that M. uniflorum ‘Yazhou’ is possibly suitable for shallow seeding.