Floral morphogenesis of Celtis species: implications for breeding system and reduced floral structure

Author(s)

Leme, Flavia M. ^{[1, 2]} ; Staedler, Yannick M. ^[3] ; Schonenberger, Jurg ^[3] ; Teixeira, Simone P. ^[4]

Affiliation

^[1] Univ Estadual Campinas, Inst Biol, Programa Posgrad Biol Vegetal, R Monteiro Lobato 255, BR-13083862 Campinas, SP - Brazil

^[2] Univ Fed Mato Grosso do Sul, Inst Biociencias, Lab Bot, BR-79070900 Campo Grande, MS - Brazil

^[3] Univ Vienna, Dept Bot & Biodivers Res, Rennweg 14, AT-1030 Vienna - Austria

^[4] Univ Sao Paulo, Fac Ciencias Farmaceut Ribeirao Preto, Dept Ciencias Farmaceut, Av Cafe S-N, BR-14040903 Ribeirao Preto, SP - Brazil

• Document type: Journal article
• Source: AMERICAN JOURNAL OF BOTANY; v. 108, n. 9 SEP 2021.
• Web of Science Citations: 0

Abstract

Premise Celtis is the most species-rich genus of Cannabaceae, an economically important family. Celtis species have been described as wind-pollinated and andromonoecious. However, the andromonoecy of Celtis has been debated because there are reports of monoclinous flowers with non-opening anthers on short filaments. Our objective was to study the floral morphogenesis of Celtis to establish the breeding system and to better understand the developmental patterns that lead to the formation of reduced flowers in the genus. Methods Flowers and floral buds of Celtis species were studied using scanning electron microscopy, high-resolution x-ray computed tomography, and light microscopy. Results All flowers initiate stamens and carpels during early floral development, but either stamens or carpels abort during later stages. Thus, at anthesis, flowers are either functionally pistillate or functionally staminate. In pistillate flowers, stamens abort late and become staminodes with normal-looking anthers. These anthers have no functional endothecium and, in most of the species studied, produce no viable pollen grains. The gynoecium is pseudomonomerous, and its vascularization is similar in the sampled species. In staminate flowers, the gynoecium aborts early resulting in small pistillodes. No vestiges of petals were found. Conclusions The species studied are monoecious and not andromonoecious as described earlier. The absence of petals, the carpel and stamen abortion, and the pseudomonomerous gynoecium result in the reduced flowers of Celtis species. The use of high-resolution x-ray computed tomography was essential for a more accurate interpretation of ovary vascularization, confirming the pseudomonomerous structure of the gynoecium. (AU)

• FAPESP's process: 14/07453-3 - Floral development of urticalean rosids
• Grantee: Simone de Pádua Teixeira
• Support Opportunities: Regular Research Grants
• FAPESP's process: 18/03691-8 - SECRETORY STRUCTURES IN ROSALES SPECIES
• Grantee: Simone de Pádua Teixeira
• Support Opportunities: Regular Research Grants