Resumo

BARCENAS-ARGUELLO, María Luisa; LOPEZ-MATA, Lauro; TERRAZAS, Teresa  e  GARCIA-MOYA, Edmundo. Seed germination of three Cephalocereus (Cactaceae) endemic species from the Tehuantepec Isthmus, México. Polibotánica [online]. 2013, n.36, pp.105-116. ISSN 1405-2768.

We studied the germination process of three species of Cephalocereus (C. apicicephalium, C. nizandensis, C. totolapensis) endemic to the Isthmus of Tehuantepec, Oaxaca, Mexico under the hypotheses that seeds lose their germination capacity as the days go after harvesting and the germination is different between species but not between collecting sites of the same species. Seeds were collected at seven sites and seeds were sown on four dates, placing 30 seeds in two or three Petri dishes per collecting site. The dishes were placed in a controlled environment chamber and germination was recorded daily for 30 days, considering a germinated seed when the radicle protruded. Germination percentage (38.8% in C. totolapensis to 55.1% in C. apicicephalium) and germination rate (1.6 in C. apicicephalium, Guiengola-2 to 24 in C. apicicephalium, Guingola-1 and C. nizandensis, La Mata) were different between species (P<0.0001). All seeds that germinated did so before the fifth day after sowing, although they have more than 100 days after harvest, suggesting the existence of induced dormancy. The significant differences in germination among populations of the same species could be a response to the particular environmental factors prevailing in each population.

Palavras-chave : days after germination; Cephalocereus nizandensis; Cephalocereus totolapensis; germination time; Oaxaca.

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