Fig. 1

Schematic representation of the steps involved in visualising the internal structures of ovules within cleared cereal pistils. a Plants were examined to identify tillers containing developing spikes. b, c Individual florets were removed from spikes to identify those at anthesis stage, achieved via observation of pollen on fingernails after anther squashing. c, d Whole pistils and anthers were gently removed and placed in fixative, followed by dehydration in an ethanol series and clearing in Hoyer’s solution. e Pistils were transferred to glass slides and covered with glass coverslips. f Samples were examined using DIC microscopy and Zeiss ZEN software