Effects of salinity, alkalinity, temperature and their interactions on seed germination of Medicago falcata

In the present study, the effects of salinity, alkalinity, temperature and their interactions on seed germination of Medicago falcata were evaluated by treated with two neutral salts (NaCl, Na2SO4), two alkaline salts(Na2CO3, NaHCO3), and three alternating temperature(10/20 ℃, 15/25 ℃ and 25/35 ℃). The results showed that seed germination percentage and germination rate were significantly affected (P<0.05) by salinity, alkalinity, temperature and their interactions. The seed germination percentage and germination rate were the highest under treatments at 10/20 ℃ or 15/25 ℃, and there was no significant difference between them. The seed germination percentage and germination rate decreased with the increasing of salinity and alkalinity concentrations and the deleterious effect of alkali stress was more severe than salt stress. Seed germination was significantly inhibited by treatment at 25/35 ℃ which also aggravated the inhibition of alkali and salt stress on seed germination. M. falcata had some tolerance to alkaline salts and high pH which germinated well under 25 mmol·L-1 Na2CO3 and 30 mmol·L-1 NaHCO3 treatments.