Germination characteristic and reproductive phenology of four coexisting species of the genus Gymnocalycium (Cactaceae)

GURVICH, D. E., FUNES, G., GIORGIS, M.A. & DEMAIO, P.

NATURAL AREAS JOURNAL

NATURAL AREAS ASSOC

Año: 2008 vol. 28 p. 104 - 108

0885-8608

We analyzed germination percentages and germination rates at four temperature treatments(5/15, 10/20, 15/25 and 20/35 ºC) and in light or darkness in four endemic species of the genus Gymnocalyciumwith different flowering phenologies from the Córdoba Mountains (Argentina). Gymnocalyciumbruchii 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, germination was higher at the two warmest treatments. Gymnocalycium bruchii germinationwas maximum at the second warmest temperature (15/25 ºC) and did not germinate at all at the highesttemperature treatment (20/35 ºC). Germination varied strongly among species, from about 80% inG. quehliaum to 20% in G. monvillei. Germination rate (t50) varied more strongly among temperaturetreatments (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.