About the Cover
Species in the genus Streptocarpus vary markedly in leaf development and morphology. Caulescent species produce leaves from a shoot apical meristem (SAM), whereas acaulescent species lack a conventional SAM and produce only a single leaf (unifoliate form) or clusters of leaves from the base of more mature leaves (rosulate form). KNOX genes are known to be important in regulating meristem function and leaf development in model species with conventional morphologies. Harrison et al. (pages 430-443) analyzed two KNOX genes from a number of Streptocarpus species with different growth forms to investigate their potential involvement in the evolution of this genus. The analysis pointed to a gene duplication event before the subgeneric split of Streptocarpus and supported the notion of multiple evolutionary origins of rosulate and unifoliate species. KNOX proteins may have played an indirect role in the developmentof morphological diversity. The cover image shows the unifoliate species S. dunnii in flower.
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Copyright © 2007 by the American Society of Plant Biologists
