Inheritance of the low-activity CAD allozyme. (a) Each lane contains megagametophyte extract from one seed of clone 7-56, costained for CAD and G6PDH. (b) Inheritance in megagametophytes (M) and embryos (E) within individual seeds, from a cross of two trees with four different cad alleles: the low-activity allozyme and a slow (S) mobility allozyme, clone 7-56, maternal parent; intermediate (I) and fast (F) alleles, from the pollen parent.