Germination Response in a Large-Seeded Neotropical Tree Species, Gustavia superba (Lecythidaceae)

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Abstract
This 6-mo. study examined percent germination, days until germination, and early seedling survival of G. superba (Lecythidaceae) through field experiments in a tropical moist forest in Panama. The study had 3 goals: to examine whether germination is a factor determining density of seedlings at 3 forest sites with different ages; to test whether burial of seeds affects germination; and to test if microsite conditions associated with light gap, gap-edge, or forest understory influence germination. The experiment, which was designed to fit a 3 way analysis of variance model, used 3 study sites, 3 microsites, 2 burial treatments, 4 replicates and 25 seeds in each replicate (1800 seeds total). Although seedling densities of G superba at the forest sites varied inversely with age of forest, there was no evidence that germination success contributes to this pattern. Results indicated that this species germinates readily under most conditions: the overall mean was 85.4% and only 6 of 72 plots had < 70% germination. Germination percent was reduced and mean number of days until germination was increased in the largest light gap. Percent germination and days until germination did not differ among sites when only seeds in the understory microsite were compared. Burial of seeds and microsite conditions had minor effects on germination. Seedling mortality occurring soon after germination was not large (5.7%) G. superba is not a tropical species whose seeds germinate in response to a light gap but its seeds do germinate successfully under a range of microsite conditions.