While the commonality of recalcitrant seeds is that they cannot be dried to low moisture contents or stored for long periods of time without damage, the biochemical mechanisms that contribute to this problem may vary among genera and even among species within a genus. We examined recalcitrant-seeded species of Quercus,Acer, and Aesculus for biochemical changes that might occur during storage or during desiccation at room temperature. While changes in the composition of storage lipids were inconclusive,we did find structural shifts in membrane lipids and proteins,and amounts of sucrose. In one experiment using two subsets of Q. a[ba acorns kept at room temperature for 12 days, the subset that desiccated exhibited large shifts in sucrose content while the subset that was kept fully hydrated exhibited much smaller changes. It is our conclusion that the sucrose in the hydrated seeds is utilized for normal growth and development while sucrose in the desiccating seeds may function secondarily as a glycoprotectant. However, while the presence of sueros. e may protect membranes from disruption in the drying acorns,it does not function to preserve acorn viability.