Microstructure and Water Uptake of Phaseolus and Winged Beans

The role of seed microstructure in initial water uptake during the soaking of Phaseolus and winged bean seeds was investigated. Considering their relatively small area, hilum and micropyle seemed to be the most important structural features influencing the initial water uptake. Seed coat played a dominant role only after its initial resistance to water uptake was overcome. Varieties with high initial water uptake also had relatively thin seed coats, a loosely arranged cell structure on the raphe‐side of the hilum, a deeply grooved hilar fissure, and a narrow tracheid bar. Water absorption in legumes appeared to be a complex process with the seed coat, hilum and micropyle together constituting an integrated water absorption system.