The moisture relations of seed longevity in Astronium urundeuva (Fr. All.) Engl.

The moisture relations of seed longevity in two populations of Astronium urundeuva (Fr. All.) Engl. (aroeira) from the Pernambuco region of Brazil were studied. The classification of aroeira seeds as orthodox and their potential for long-term storage under seed bank conditions (15% relative humidity (rh), -20°C) were confirmed. A single regression adequately described the negative logarithmic relation between seed moisture content and longevity for the two populations. Analysis of the predicted longevity of 11 trees and 11 non-trees, where predictions were based on moisture contents in equilibrium with standard seed bank drying conditions (15% rh) and storage at -20°C, gave similar estimates of mean longevity for the two groups (trees: 643 years; non-trees: 737 years) with considerable variation in the estimates for individual species. Whilst there was a significant positive correlation between predicted longevity and oil content for trees, there was no relationship between these parameters accross all 22 species. The semi-logarithmic relation between equilibrium relative humidity and longevity for aroeira is discussed in relation published data for herbaceous crops.