Fig. 4

Ovule morphology after clearing. Ovule images are presented as composites, generated by merging optical sections. The method worked equally well for barley (a) and wheat (b) pistils at various stages. Pre-anthesis ovules are shown. c Measurement of traits at anthesis, including ovule area (OV_A), embryo sac area (ES_A), ovule and embryo sac transverse and longitudinal dimensions (OV_L, OV_T, ES_L, ES_T), integument width (INT_W), antipodal number (marked with crosses) and antipodal cluster area (ANT_A), using Zeiss ZEN software. The ovule area is indicated with a dashed red and white line, while the embryo sac area is indicated by a dashed black and white line. NUC = nucellus. Small (d) and large (e) mature barley ovules after clearing imaged at ×10 magnification without dissection from the pistil. Bar 100 μm