Fig. 1.

Bif1 and Bif4 mutant phenotype. (A) Mature tassel phenotype. Normal tassels produce spikelets and flowers that are reduced in both mutants. (Inset) Spikelets with protruding anthers. tb, tassel branch. spk, spikelet. (B) Mature ear phenotype. (C–E) Scanning electron microscope image of early tassel and ear development in normal and mutant plants. Arrowheads point to a few axillary meristems forming in mutant plants. Primordia are absent in homozygous Bif1 mutants. Boxed region in D marks the peripheral zone of the IM. (E) Close-up of the peripheral zone of the IM. White and yellow colors mark suppressed bract primordia and AMs, respectively. Note the acropetal development of primordia (from top, younger, to bottom, older).