Efeitos da luz e da temperatura na germinação de sementes de Eremanthus (Asteraceae), ocorrentes na Serra do Cipó, MG, Brasil

Abstract

Studies of germination are important for the propagation of plants, and the regeneration and the preservation of plant communities. The purpose of this study was to evaluate the viability and the germinative behavior of the seeds of Eremanthus elaeagnus (Mart. ex DC.) Schultz-Bip, E. glomerulatus Less. and E. incamus (Less) Less. The viability of seeds was confirmed through the tetrazolium test. Germination tests were conducted under continuous light and darkness at constant temperatures of 15, 20, 25, 30, 35 and 40 ºC and at alternated temperatures (photoperiod of 12 hours) range from 15-25, 15-30, 15-35, 20-30, 20-35 and 25-35 ºC. Seed viability varied significantly among years and populations. The germination percentage was always low, due mainly to absence of embryos. The seeds of E. elaeagnus germinated at temperatures from 15 to 30 ºC; E. glomerulatus at temperatures from 20 to 30°C; and E. incamus at temperatures from 15 to 35 ºC. The three species germinated in light and darkness, presenting significant differences between these treatments only at temperatures of 25 and 35 ºC (E. incanus) and 30 ºC (E. glomerulatus). Eremanthus incanus presented a higher germination percentage over a wider temperature range, and its seeds germinated faster than E. elaeagnus and E. glomerulatus.