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Germination phases of Annona emarginata (Schltdl.) H. Rainer seeds under different temperatures

This study was carried out with the aimed to identify the germination phases of "araticum-de-terra-fria" (Annona emarginata (Schltdl.) H. Rainer) seeds under different temperatures. Thus, the work was divided into two experiments: one for evaluating phases I and II, and a second one for phase III. The experimental design was completely randomized, with 3 treatments and 4 replicates of 25 seeds per plot in both experiments. Treatments consisted of constant temperatures equal to 25ºC and 30ºC, besides the alternate temperature 20-30ºC (8-16h, respectively), under constant light. Humidity degree variation over time (experiment 1), and germination percentage and mean velocity (experiment 2) were assessed. Data were subjected to analysis of variance, and means were compared by the Tukey's test at 5% significance, besides polynomial regression. Humidity degree variation over time was evaluated through non-linear monomolecular regression; the parameters of functions were compared according to treatments, then fit and subjected to analysis of variance and Tukey's test at 5% significance. Seeds kept at 30ºC had higher water absorption velocity, peaking 27.85% humidity degree during the change from phase I to phase II. When seeds were subjected to 25ºC, phase I lasted 60 h, peaking 28.35% humidity degree. Under 20/30ºC, such phase lasted 72 h, peaking 28.33% humidity degree. The temperature 30ºC led to the highest imbibition velocity but not to a higher germination percentage (phase III), which was detected in seeds kept at 20/30ºC.

Annonaceae; "araticum-de-terra-fria"; imbibition


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