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

The moisture relations of seed longevity in two populations of Astronium ur undeuva (Fr. All.) Engl. (aroeira) from the Pernambuco region of Brazil wer e studied. The classification of aroeira seeds as orthodox and their potent ial for long-term storage under seed bank conditions (15% relative humidity (rh), -20 degrees C) were confirmed. A single regression adequately descri bed the negative logarithmic relation between seed moisture content and lon gevity for the two populations. Analysis of the predicted longevity of 11 t rees and 11 nontrees, a here predictions were based on moisture contents in equilibrium with standard seed bank drying conditions (15% rh) and storage at -20 degrees C, gave similar estimates of mean longevity for the two gro ups (trees: 643 years; non-trees: 737 years) with considerable variation in the estimates for individual species. Whilst there was a significant posit ive correlation between predicted longevity and oil content for trees, ther e was no relationship between these parameters accross all 22 species. The semi-logarithmic relation between equilibrium relative humidity and longevi ty for aroeira is discussed in relation to published data for herbaceous cr ops.