Grass spikelets: a thorny problem

Isolation of a maize gene with strong homologies to the Arabidopsis floral organ identity gene APETALA2 has provided new insights to understanding the generation of architecture in grass inflorescences. Grass inflorescences are built of repeated units called spikelets, which consist of a pair of glumes (bracts) enclosing a cluster of one to as many as 40 flowers, the number depending on the species. The gene indeterminate spikelet (ids), isolated by Chuck and co-workers,⁽¹⁾ is involved in limiting the number of floral meristems produced by the spikelet meristem in maize inflorescences. Altered regulation of activity of ids homologues may be responsible for variation in flower number among different grasses. BioEssays 20 :789–793, 1998. © 1998 John Wiley & Sons, Inc.