Effects of post‐fire heating on germination and early growth of two congeners of Dimorphandra species from Cerrado and Atlantic Forest

Plants in the Atlantic Forest are not adapted to fire. On the other hand, in the Cerrado, fire occurs naturally, favoring species morphophysiologically adapted to its seasonality. However, little is known about the influence of the post‐fire scenario on the germination of woody species in these two biomes. The objective of the present study was to evaluate the impact of post‐fire heating on the germination and early growth of two species of the genus Dimorphandra . The seeds of Dimorphandra mollis (Fabaceae, Cerrado) and D. exaltata (Atlantic Forest) underwent three pre‐germination treatments: control at ambient temperature, 30 days of heating (simulating fire in the mid‐dry season), and 7 days of heating (simulating fire at the end of the dry season) at 45°C day and 10°C night in a Biochemical Oxygen Demand Incubator. Dimorphandra mollis seeds had a shorter germination time than D. exaltata in heating treatments. A higher hypocotyl–root axis was found in D. mollis seedlings under control temperature, but this species showed a decrease in the hypocotyl–root axis in both heating treatments. Reduced root growth could decrease the ability of this species to compete for resources under the soil. The germination interval in D. exaltata seeds in the heating treatments may be slower, scattering recruitment over time in such conditions, but this could be a survival strategy for plants in disturbed environments. The post‐fire scenario was detrimental to germination and early development, delaying germination and impairing the growth of the hypocotyl–root axis in plants of the genus Dimorphandra.