In this study, the seed germination behavior of two sympatric plant species that occur in habitats under diferent nutritional and moisture conditions at Serra do Cipó, Southeastern Brazil, was evaluated. Seeds collected in the year of 2000 were placed to germinate in four replicates of 25 seeds under the temperatures at 15, 20, 25 and 30ºC, and at 12 hour photoperiod. L. cordata showed higher germination percentage than L. francavillana (t=11.803, gl=30, p<0.01) as well as the radicle emergency rate (t=6.71, gl=30, p<0.01). L. cordata showed the highest radicle emergency rate (ANOVA, F=14.282, r²=0.78, p<0.01) under temperatures of 20ºC and above. Under 20ºC this species showed a tendency of higher germination percentages (p>0.05, N.S.). The germination percentages were correlated with the the radicle emergency rate for this species (r²=0.63, p<0.05, y=1.48x+1.97). L. francavillana showed the highest germination percentages (ANOVA, F=3.388, r²=0.46, p<0.05) and a tendency for higher the radicle emergency rate under 25ºC (p>0.05, N.S.). The germination percentages were also correlated with the radicle emergency rates (r²=0.90, p<0,01, y=4.32x-0.01). Our results indicate fisiological diferences in the seed germination of L. cordata and L. francavillana. Those diferences may reflect adaptations to the diferent microhabitat conditions which the two species are subjected.
Lavoisiera; seed germination; rupestrian fields; temperature; threatened species
