SEED-GERMINATION AND DORMANCY STRATEGIES OF TEMPERATE RAIN-FOREST SPECIES IN CHILOE, CHILE

To investigate the presence of dormancy mechanisms, we conducted compa rable germination assays for 46 species of the temperate forests of Ch iloe Island, including trees, shrubs, vines, hemiparasites and herbs. Within one week of field collection, all seeds, devoided of pulp or fr uit structures, were divided in two groups: (1) half of the seeds were placed in a germination chamber under controlled temperature (20/10 d egrees C), without any previous treatment; and (2) the second half of the seeds were stratified at 5 degrees C for a period of 40 days and t hen germinated under the same temperature conditions as group (1). Str atification affected seed germination in 54% of the species. For 11% o f the species, cold stratification seems to break innate dormancy beca use the final percentage of germination was much lower for non-stratif ied seeds. Germination rates were increased by cold stratification in 22% of the species, without altering the final germination percentage. In another 11% of the species cold stratification resulted in reduced germination compared to non-stratified seeds. The most common germina tion strategy among temperate forest species in Chiloe was rapid germi nation and apparent lack of innate dormancy mechanisms (63% of all spe cies). In 38% of the species, rapid germination was also synchronous, i.e., greater than or equal to 90% of the seeds germinated within one month regardless of seed sources. The strategy of germinating immediat ely after fruit ripening observed in the majority of temperate rain fo rest species in Chiloe is also common among plant species in many trop ical forests, but it is unusual among species in temperate forests of the northern hemisphere, where delayed germination and innate dormancy predominate.