Caracterização ecofisiológica da germinação de sementes de Araucaria angustifolia em campo e laboratório

• Autor(a) principal: Santos, Thales Barbosa dos [UNESP]
• Data de Publicação: 2016
• Tipo de documento: Trabalho de conclusão de curso
• Idioma: por
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://hdl.handle.net/11449/156082; http://www.athena.biblioteca.unesp.br/exlibris/bd/capelo/2017-09-28/000890271.pdf
• topic: Sementes; Pinheiro-do-parana; Umidade; Temperatura; Seeds

Seeds of Araucaria angustifolia have great economic and ecological importance. However, there are few studies concerning the germination performance of these seeds under field conditions. It is known that its seeds are recalcitrant and the best germination performance is between 20º-25ºC. Moreover, seed dispersal occurs between March and July, when temperatures are lower than 20º C. The objective of this study was to evaluate the influence of different conditions of temperature and humidity in germination of A. angustifolia seeds, both in natural and laboratory conditions. Mature seeds of A. angustifolia were harvested in Campos do Jordão, SP, at the beginning of pine seeds fall (March). In the field, two conditions of germination were tested: seeds buried at a depth of ± 7 cm and seeds placed on the soil surface, inside exclusion cages. During the experiment, we measure germination percentage (%G), soil and seeds humidity, and also precipitation data was collected. We measured daily soil and air temperature oscillation. At the laboratory, seeds were incubated inside germination chambers, simulating daily temperature oscillation of soil and air observed on field. On field, germination of buried seeds started after 15 days and reached maximum rate %G (97%) after 60 days. Seeds above the soil started germination after 30 days and maximum rate (79%) occurred after 75 days, coinciding with the maximum precipitation. At the laboratory, there were no significant differences in germination percentage among treatments. We concluded that the burial of Araucaria angustifolia seeds (considering casual dispersers) provided better conditions for germination, both in relation to humidity and temperature, when compared to seeds left on the surface of the Araucaria forest