Germinação de sementes de espécies medicinais do Rio Grande do Sul: Bromelia antiacantaha Bert., Cuphea carthagenensis (Jacq.) Macbride e Talinum patens (Jacq.) Willdenow

Abstract

RESUMO -(Germinação de sementes de espécies medicinais do Rio Grande do Sul: Brolllelia allliacantha Bert., Cuphea carthagenensis (Jacq.) Macbride e Talinulll patens (Jacq.)Wi11denow). As espécies estudadas são ervas de expressiva dispersão no Estado do Rio Grande do Sul e com uso difundido na farmacopéia popular. Estudou-se a intluência de diferentes temperaturas constantes (lO, 15 , 20, 25,30 e 35°C) sob condição ·de escuro ou de luz (fotoperíodo: luz/escuro 8h116h) e as temperaturas alternadas (10-20, 15-25, 20-30 e 25-35°C) sobre o comportamento germinativo das sementes. As sementes não germinadas foram submetidas ao teste de tetrazólio. Sementes de B. anliacalllha germinaram acima de 80% nas temperaturas constantes de 25, 30 e 35°C na luz e no escuro. Abaixo de 25°C, as sementes apresentaram dormência relativa. No armazenamento por um ano sob condições ambientais (25°C) e sob refrigeração (5°C), a viabilidade das sementes foi mantida em 90%. Sementes de C. carthagenensis germinaram acima de 80% nas temperaturas alternadas. Em temperaturas constantes, a germinação foi nula, mas as sementes estavam viáveis. Em T. patens constatou-se acima de 50% se sementes deterioradas e a germinabilidade foi semelhante nas temperaturas constantes em relação às alternadas. As três espécies podem ser propagadas através de sementes, se as condições de temperatura apropriadas forem observadas.Palavras-chave -Brolllelia, Cuphea, Ta[ülUlIl , temperatura, luz , germinação ABSTRACT -(Seed germination of medicinal plants of Rio Grande do Sul State, Brazil: Brolllelia antiacalllha Bert., Cuphea carthagenensis (Jacq.) Macbride and Talinulll patens (Jacq.) Wi11denow). These species of herbs are we11 distributed over ali Rio Grande do Sul State, and are used to prepare medicine for the human population. The intluence of constant temperatures (lOOC; 15°C; 2OOC; 25°C; 300C and 35°C) on the germination of seeds during a photoperiod of 8 hours, was analyzed. Experiments were also performed in darkness, and at alternating temperatures (15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35). Seeds that did not germinate were submitted to the tetrazolium test. Over 80% of the seeds of B. antiacalllha germinated at constant temperatures of 25°, 300 ar 35°C, both in light and darkness. Below 25°C, the seeds presented reI ative dormancy. Storage during one year under laboratory conditions (25°C), ar at a low temperature (5°C) allowed for 90% of seed viability. Over 80% of the seeds of C. carthagensis germinated at alternating temperatures, but no germination was I

Light and temperature requirements for germination of seeds of Aechmea nudicaulis (l.) Griesebach and Streptocalyx floribundus (Martius ex Shultes f.) Mez (Bromeliaceae)

“…In contrast to bromeliads of shaded habitats as gallery and deciduous forests (Garcia-Franco & Rico-Gray 1991;Rosa & Ferreira 1998), but similar to bromeliads of restinga as Aechmea distinchantha and Neuregelia cruenta (Mercier & Guerreiro Filho 1990), seeds of A. nudicaulis and S. floribundus require light in order to germinate. Bromeliads that produce light-requiring seeds (Mercier & Guerreiro Filho 1990) were found to be shade-intolerant, as the case of N. cruenta and A. nudicaulis (Fischer & Araújo 1995).…”

Seed germination ecophysiology of the wild pineapple, Ananas ananassoides (Baker) L.B.Sm. (Bromeliaceae)

“…Studies focusing on light effects on germination of Bromeliaceae seeds have yielded contrasting results, with fi ndings of negative, neutral, and positive effects (Mercier & Guerreiro-Filho 1990;Rosa & Ferreira 1998;Pinheiro & Borghetti 2003;Garcia & Oliveira 2007;Tarré et al 2007;Vieira & Silveira 2010). seeds of A. ananassoides are photoblastic and seed storage did not affect their photoblastism.…”

“…The negative effects on germinability caused by high temperatures seem to be widespread in bromeliads in different ecosystems, but since bromeliad species occupy a great diversity of habitats they might respond differently to temperature (Mercier & Guerreiro-Filho 1990, Rosa & Ferreira 1998, but see Pinheiro & Borghetti 2003.…”

Can tortoises facilitate the germination of plants with dry fruits? A simulation of the effects of Chelonoidis carbonarius (Testudines: Testudinidae) on the germination of Leucaena leucocephala (Fabaceae)

“…Each replicate was placed in moist chambers containing washed and autoclaved river sand at constant temperature of 25 o C and with 20-W fluorescent lamps, giving a radiant flux of about 50 mol m -2 s -1 (Rosa & Ferreira 1998) for 12 hours/day. The experiment was kept for 30 days with daily observations and followed the recommendations of the Rules for Seed Analysis (Brasil 1992).…”