Figure 1

Differential interference contrast images of cleared Sorghum bicolor ovules in sagittal section. A) Procedure used to measure ovule area components (germ cell, nucellus and integuments), ovule curvature (angle), and inner integument length (distance from base to tip); from Carman [29], used with permission (caudatum, Agira, PI217855). B) Three degenerating megaspores (DM), the functional megaspore (FM), an aposporous initial (AI), and two large stack cells (LSC) (RIL, TX 37-6). C) Four DM and a vacuolate (VAC) 1-nucleate aposporous embryo sac (AES) (RIL, TX 152-6). D) Three DM, a degenerating FM, two AI, one of which is absorbing the FM, and two LSC (RIL, TX 4-7). E) Four DM and a 2-nucleate AES (breeding line, IS3620C).