The timing and the extent of the breakdown of endosperm galactomannans, and the fact that galactose and mannose do not accumulate in the endosperm, provide very strong evidence that galactomannans function as storage com¬pounds. In addition, they are very hard when dehydrated and, thus, provide mechanical protection to the embryo in the resting seed. More importantly for, seeds in semi-arid habitats, galactomannans have the ability to absorb large quantities of water forming mucilages or gums that provide the germinating embryo with an ‘osmotic buffer’, and thus protect it from water stress (Reid and Bewley, 1979).