EFEITO DE CHOQUES TÉRMICOS NA GERMINAÇÃO DE DUAS ESPÉCIES DE Handroanthus Mattos DO CERRADO

Abstract

The Brazilian Cerrado is considered one of the richest biomes in biodiversity, with plant species adapted to extreme environmental conditions, including frequent fires, of both natural and anthropic origin. The frequency and intensity of fire can interfere with the reproductive capacity of plants through its effects on the soil seed bank, either promoting germination or causing a significant reduction in germination and even seed death. Considering these aspects, this study aimed to investigate the effect of heat shocks on seed germination of Handroanthus chrysotrichus and H. serratifolius, woody species occurring in savanna physiognomies of the Cerrado. For this, the seeds were subjected to temperatures of 80, 110, 140 and 170ºC for 2.5 and 5 minutes. Subsequently, they were stored in moistened Petri dishes and incubated in a growth chamber at 25ºC. The results indicated that H. chrysotrichus seeds tolerate temperatures up to 80ºC, but have their germination reduced at temperatures above 110ºC. On the other hand, H. serratifolius seeds showed greater tolerance to heat, with germination observed up to 140ºC for 2.5 minutes. For both species studied, exposure to temperatures above 170ºC was lethal for their seeds.