0000000001080800
AUTHOR
Kester Bull-hereñu
Patterns of flower development in Apiaceae–Apioideae
Abstract Apiaceae is a large family characterized by uniform flowers. However, early ontogenetic studies revealed unexpected diversity in flower development. In the present paper, we investigate eight species representing six tribes of subfamily Apioideae to address diversity in developmental patterns. One focus is on the developmental divergence of sex morphs in andromonoecious species. Scanning electron microscopic studies were conducted on six herbaceous species: Chaerophyllum bulbosum , Daucus carota , Dorema aucheri , Ferula hezarlalehzarica , Orlaya grandiflora , Pastinaca sativa , and two woody species, i.e., Bupleurum fruticosum and Seseli ghafoorianum . Our results confirm the exis…
The unique pseudanthium of Actinodium (Myrtaceae) - morphological reinvestigation and possible regulation by CYCLOIDEA-like genes
Background Genes encoding TCP transcription factors, such as CYCLOIDEA-like (CYC-like) genes, are well known actors in the control of plant morphological development, particularly regarding the control of floral symmetry. Despite recent understanding that these genes play a role in establishing the architecture of inflorescences in the sunflower family (Asteraceae), where hundreds of finely organized flowers are arranged to mimic an individual flower, little is known about their function in the development of flower-like inflorescences across diverse phylogenetic groups. Here, we studied the head-like pseudanthium of the Australian swamp daisy Actinodium cunninghamii Schau. (Myrtaceae, the …
Towards an ontogenetic understanding of inflorescence diversity
Backgrounds and aims Conceptual and terminological conflicts in inflorescence morphology indicate a lack of understanding of the phenotypic diversity of inflorescences. In this study, an ontogeny-based inflorescence concept is presented considering different meristem types and developmental pathways. By going back to the ontogenetic origin, diversity is reduced to a limited number of types and terms. Methods Species from 105 genera in 52 angiosperm families are investigated to identify their specific reproductive meristems and developmental pathways. Based on these studies, long-term experience with inflorescences and literature research, a conceptual framework for the understanding of infl…
Testing the ontogenetic base for the transient model of inflorescence development
† Backgrounds and Aims: Current research in plant science has concentrated on revealing ontogenetic processes of key attributes in plant evolution. One recently discussed model is the ‘transient model’ successful in explaining some types of inflorescence architectures based on two main principles: the decline of the so called ‘vegetativeness’ (veg) factor and the transient nature of apical meristems in developing inflorescences. This study examines whether both principles find a concrete ontogenetic correlate in inflorescence development. † Methods: To test the ontogenetic base of veg decline and the transient character of apical meristems the ontogeny of meristematic size in developing inf…
Open and closed inflorescences: more than simple opposites
The absence of a terminal flower in inflorescences (‘open inflorescences’) is currently explained by the maintenance of putative stem-cells in the central zone (CZ) of the inflorescence meristem (IM) governed by the CLAVATA– WUSCHEL regulatory loop. Disruption of this regulatory pathway, as in Arabidopsis TERMINAL FLOWER LOCUS 1 mutants, leads to terminal flower production. However, recent studies in other taxa reveal novel mechanisms of inflorescence termination; for example, the SEPALLATA-like MADS-box floral identity gene GERBERA REGULATOR OF CAPITULUM DEVELOPMENT 2 in Gerbera excludes the retention of a CZ as an ontogenetic cause for the openness of these inflorescences. Moreover, compa…
Live imaging of developmental processes in a living meristem of Davidia involucrata (Nyssaceae)
Morphogenesis in plants is usually reconstructed by scanning electron microscopy and histology of meristematic structures. These techniques are destructive and require many samples to obtain a consecutive series of states. Unfortunately, using this methodology the absolute timing of growth and complete relative initiation of organs remain obscure. To overcome this limitation, an in vivo observational method based on Epi-Illumination Light Microscopy (ELM) was developed and tested with a male inflorescence meristem (floral unit) of the handkerchief tree Davidia involucrata Baill. (Nyssaceae). We asked whether the most basal flowers of this floral unit arise in a basipetal sequence or, altern…