Leaf morphology in angiosperms is coordinated by transcription factors from several gene families, three of which are considered in this study. Class 1 knotted-like homeobox (KNOX1) genes control meristematic identity, and are implicated in dissection of Lycopersicon esculentum (tomato) leaves. Genes in the FLO (floricaula) family regulate floral meristem identity, but also regulate compoundedness in Pisum sativum (pea) leaves. Phantastica (PHAN) belongs to the MYB domain family of transcription factors and regulates adaxial identity in Antirrhinum majus (snapdragon) leaves. Leaf developmental patterns in the Papaveraceae have recently been placed in phylogenetic context; therefore, expression analysis of KNOX1, FLO and PHAN provides insight to the interplay of these genes with evolution of leaf form. Phantastica has not been studied in species with dissected leaves, but it may control rachis identity. Gene homologues were isolated from Eschscholzia californica, Chelidonium majus and Dactylicapnos torulosa by RT-PCR (reverse transcriptase polymerase chain reaction) and RACE (rapid amplification of cDNA ends) techniques on shoot apical RNA. Ribonucleotide probes of these homologues were used for in situ hybridization (ISH) to mRNA in sections of shoot apices. Histone H4 was used as a positive control for ISH. It is hypothesized that these species will follow the pea type of KNOX1 and FLO expression pattern because the Papaveraceae is more closely related phylogenetically to pea than to tomato.

Key words: Chelidonium majus, Dactylicapnos torulosa, Eschscholzia californica, gene homologues, leaf development, leaf dissection