Estudos de germinação são importantes para a propagação de plantas, regeneração e conservação de comunidades vegetais. O objetivo deste trabalho foi avaliar a viabilidade e o comportamento germinativo de sementes de Eremanthus elaeagnus (Mart. ex DC.) Schultz-Bip, E. glomerulatus Less e E. Incanus (Less.) Less. A viabilidade das sementes foi verificada através do teste de tetrazólio. Os testes de germinação foram realizados sob luz e escuro contínuos em temperaturas constantes de 15, 20, 25, 30, 35 e 40 ºC e em temperaturas alternadas (fotoperíodo de 12 h) de 15-25, 15-30, 15-35, 20-30, 20-35 e 25-35 ºC. A viabilidade das sementes variou significativamente entre populações e diferentes anos de coleta. As percentagens de germinação das sementes foram sempre baixas, devido, principalmente, à ausência de embriões. Sementes de E. elaeagnus germinaram nas temperaturas de 15 a 30ºC, de E. glomerulatus de 20 a 30 ºC e E. incanus de 15 a 35 ºC. As três espécies germinaram na luz e no escuro, apresentando diferenças significativas entre estes dois regimes apenas nas temperaturas de 25 e 35 ºC (E. incanus) e 30 ºC (E. glomerulatus). Em comparação com as outras espécies Eremanthus incanus apresentou maiores percentagens de germinação em faixa de temperatura mais ampla e suas sementes são mais rápidas para germinar.
-(Variation between three Eremanthus (Asteraceae) species in their ability to form a seed bank)-Knowledge on seed bank function is fundamental for understanding the species regeneration patterns. This investigation was carried out to compare the ability of Eremanthus elaeagnus (Mart. ex DC.) Schultz-Bip, E. glomerulatus Less., and E. incanus (Less.) Less. to form a soil seed bank. Seeds (aquenes) of each of these three species were collected, stored in the laboratory and subsequently buried in the same area where they were collected, inside nylon bags. The bags were collected monthly or bimonthly for germination tests under continuous light and also in darkness at 20 °C (E. elaeagnus e E. glomerulatus) and at 25 °C (E. incanus). After 12 months, a further series of tests compared the germination of achenes that had been buried in soil and compared with those stored in the laboratory at 15, 20, 25, 30, 35, and 40 °C. After three months of burial, the seeds of E. elaeagnus and E. glomerulatus failed to germinate, whereas the seeds of E. incanus, even after burial for 18 months, retained germination percentage of between 1% and 30%. After one year stored in laboratory, the seeds of E. glomerulatus were no longer viable and seeds of E. elaeagnus e E. incanus had a germination percentage below that of newly collected seeds. The results showed that E. elaeagnus and E. glomerulatus do not form seed banks while E. incanus may form a small and persistent soil seed bank.
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