How long does it take for different seeds to dry?

Abstract

Reduction in rainfall and intensification of dry season moisture deficit threaten to expose desiccation-sensitive seeds in the seasonal tropics to greater potential negative effects of desiccation. A determinate affecting the recruitment of species under increased aridity is how quickly desiccation-sensitive seeds dehydrate. We investigated the rate of seed moisture loss in 24 species that produce desiccation-sensitive seeds in a seasonal tropical forest and tested the common hypothesis that seeds conform to a simple negative exponential model of moisture loss with time. A negative exponential model described moisture loss in 14 species, but was not the best model for the remaining 10 species. Moisture loss in eight species was best described by a double-negative exponential model and by a double-linear model in the remaining two species. We then tested the hypothesis that seed mass could predict the rate of desiccation between and within species. Within species the time to a given state of desiccation could be predicted by seed mass for eight species. Between species there was no relationship between desiccation rate and seed mass. We conclude that different modes of water loss and seed structural features may be more important than seed mass in prolonging desiccation.