Germination characteristics of four coexisting Gymnocalycium (Cactaceae) species with different flowering phenologies

- GURVICH, D., FUNES, G., GIORGIS, M. & DEMAIO, P.

Natural Areas Journal

Natural Areas Association

Lugar: Bend, Oregon; Año: 2008 vol. 28 p. 104 - 108

0885-8608

Abstract             Germination characteristics and flowering phenology are key elements of plant life histories, particularly in slow growing species as those of the family Cactaceae. In this study we analysed total germination percentage and germination rate at four temperature treatments (5/15, 10/20, 15/25 and 20/35ºC), and in light or darkness in four coexisting species of the genus Gymnocalycium with different flowering phenologies from the Córdoba mountains (Argentina). Gymnocalycium bruchii flowered and dispersed its seeds very early in the season in comparison to the other three species. No seeds germinated in darkness or at the coldest temperature regime. For all species except G. bruchii, total germination was higher at the two warmest treatments. Gymnocalycium bruchii total germination was maximum at the second warmest temperature (15/25 ºC) and did not germinate at all at the highest temperature treatment (20/35 ºC). Total germination varied strongly among species, from about 80% in G. quehliaum to 20% in G. monvillei. Germination rate (t50) varied more strongly among temperature treatments (from 15 to 7 days in the coldest and warmest treatments respectively) than among species. The lack of germination of G. bruchii at 20-35 °C could be related to its early flowering phenology. Key-words: Germination; Phenology; Cactaceae