Glycine max leaflets lack a base-tip gradient in growth rate.

The paradigm of dicotyledonous leaf expansion describes high relative growth rates at the leaf base, dampening towards the leaf tip. Soybean leaflet expansion was measured under different growth conditions with both conventional and time-lapse video techniques. In contrast to findings from other species, maximum growth rates occurred at approximately 2 a.m. and the basipetal growth pattern was absent, suggesting the factors controlling soybean expansion are distinct from other species.