Developmental comparison of leaf shape variation in three Chamaedorea species

Compound palm leaf development is unique and consists of two processes. First, the primordial tissue folds through differential growth. forming plications. Second, these plications separate through an abscission-like process, forming leaflets. The second process of leaflet separation allows for the development of compound leaves. The question that this study addresses concerns the development of bifid leaves. as they do not form leaflets but only develop a cleft through ail apical incision. The ideal genus to use for this study is Chamaedorea as it includes species with both pinnate and bifid leaves. Chamaedorea fragrans (Ruiz & Pav.) Mart. and Chamaedorea stolonifera H. Wendl. ex Hook. f. were chosen as the species with adult bifid leaves. Although Chamaedorea seifrizii Burret is a pinnate-leaved palm. its juvenile leaves are bifid. Scanning electron microscopy and light microscopy were used to study the development of bifid leaves. Our results indicate that neither of these bifid palms develop separation sites within the lamina, but rather the apical cleft develops through "late leaflet separation" or by ail abscission-like process. In contrast, C. seifrizii juvenile leaves exhibit "early leaflet separation" when developing the apical cleft.