INVESTIGADORES
GONZALEZ POLO Marina
congresos y reuniones científicas
Título:
Ecophysiological bases of seed germination of two Nothofagus species distributed across an altitudinal gradient in the south Andes
Autor/es:
ARANA, M. V.; GONZALEZ POLO, M.; MARTINEZ-MEIR, A.; SANCHÉZ, R. A.; BENECH-ARNOLD, R.; GALLO, L.
Lugar:
Bahía
Reunión:
Congreso; X Conference of the International Society for Seed Science; 2011
Resumen:
Germination behavior is one of the earliest phenotype expressed by plants and this fact has consequences for the evolution of post-germination traits, ecological niches and geographic ranges of species (Donohue et al 2010 Annu. Rev. Ecol. Evol. Syst. 41:293–319). Across the South Andes Mountains, it is possible to distinguish several environmental gradients although the pluviometric and altitudinal ones are probably exerting the stronger influence in the distribution and abundance of the tree species of the region. In the western Andes, around the 36° 30’ and 40° 10’ latitude south, two Nothofagus species, N. obliqua (roble) and N. nervosa (raulí), are distributed across a clear altitudinal range (roble: 600-900 meters over the sea level (msl), raulí: 900-1000 msl). The aim of this work is to study the germination behavior of these species in order to evaluate the influence of this trait in the definition of their ecological niches. Our results indicate that, in both species, cold stratification decreases the level of seed dormancy and that red light (R) promotes germination even at constant temperature. Whereas alternating temperatures were able to replace the R requirement for the stimulus of germination in raulí, the seeds of roble showed a stronger dependence on both factors. Seed morphology (bi or tri winged seeds) was associated with the germination physiology in both species. Field studies showed that seedling emergence is weakly associated with the environmental light quality, and therefore in addition to light, other factors such as temperature and soil water potential might be more relevant for the control of germination under natural conditions. Work in progress to address this last involves hidro-termal time models and field measurements in permanent plots across the altitudinal gradient.