Viability of recalcitrant Araucaria angustifolia seeds in storage and in a soil seed bank

Abstract

Araucaria angustifolia (Bertol.) Kuntze is a representative species of the Mixed Ombrophilous Forest in the Atlantic Forest Biome of Brazil. The development of a germplasm conservation protocol for long-term seed bank storage is compromised for this species, as it is sensitive to desiccation. Furthermore, in situ establishment of a soil seed bank in its natural habitat may be limited. This study evaluates the storability of two provenances of A. angustifolia seeds and their behavior in an artificial soil seed bank in two forest environments (understory and edge). Results show that both seed provenances may be stored at 5 °C for approximately 12 months, retaining high viability. The subsequent decrease in germination was associated with a reduction and an increase in seed water content, as well as with increased electrical conductivity. In the understory environment, seed viability was above 85% for the first 60 days, and at the end of the experiment (270 days), seedlings emerged. However, at the forest edge, there was a total loss of seed viability after 120 days associated with a reduction in water content and high predation. It is concluded, therefore, that short-term storage of A. angustifolia seeds is possible in a cold room, which is fundamental to supply seed demand outside the production period. Forest cover conservation is important for regeneration and conservation of the species.