Figure 2

Scanning electron mircrographs (SEMs) of spikelet structures of wild-type and bfl1 mutant plants. A, Junction of secondary rachis-branch (SB) and pedicel (PE) of spikelet in wild-type. B, A close-up of the basal part of a spikelet showing all the spikelet organs of wild-type. C, A close-up of the surface of outer rudimentary glume (ORG) and outer empty glume (OEG) of a wild-type spikelet. The cells of empty glume are orderly arranged and have a smooth flat surface, whereas the cells of rudimentary glume have irregular shapes and a rugose surface bearing hairy structures. D, Surface of inner rudimentary glume (IRG) of wild-type, having short or long hairs. E, Secondary rachis-branches of bfl1 and subsequently formed tertiary and higher order rachis-branches which develop continuously in alternating axes. F, Bract-like structure (BL) and rachis-branch meristem (BM) of bfl1. Following differentiation BL, BM either arrests its growth or continues to produce new BL. Most likely BL is equivalent to rudimentary glume because of the resemblance of the surface structures. G and H, Close-up view of the surface of BL of bfl1. Bars in all diagrams represent 100 μm. Abbreviations: SB: secondary rachis-branch; TB: tertiary rachis-branch; PE: pedicel of spikelet; ORG: outer rudimentary glume; IRG: inner rudimentary glume; OEG: outer empty glume; IEG: inner empty glume; PA: palea; LE: lemma; BL: bract-like structure; BM: branch meristem.