| Full text | |
| Author(s): |
Total Authors: 3
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| Affiliation: | [1] Univ Sao Paulo, Fac Filosofia Ciencias & Letras Ribeirao Preto, Dept Biol, Av Bandeirantes 3900, BR-14040901 Ribeirao Preto, SP - Brazil
[2] Univ Sao Paulo, Fac Ciencias Farmaceut Ribeirao Preto, Dept Ciencias Farmaceut, Av Cafe S-N, BR-14040903 Ribeirao Preto, SP - Brazil
[3] Inst Pesquisa Jardim Bot Rio de Janeiro, DIPEQ, Jardim Bot, Rua Pacheco Leao 915, BR-22460030 Rio De Janeiro, RJ - Brazil
Total Affiliations: 3
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| Document type: | Journal article |
| Source: | FLORA; v. 240, p. 116-132, MAR 2018. |
| Web of Science Citations: | 3 |
| Abstract | |
The mulberry and fig family (Moraceae) has tiny flowers with a single whorled or absent perianth and inner whorls with a reduced number of organs. Relevant questions about this reduced floral structure still remain unresolved. Thus, we studied the ontogenic processes that culminate in such a reduced flower, as well as the close relationship between the floral envelope and the androecium in Brosimum gaudichaudii, Castilla elastica, Clarisia ilicifolia, Maclura tinctoria and Morass nigra. Flower buds and flowers were processed for surface (scanning electron microscopy) and anatomical (light microscopy) analyses. The perianth consists of sepals, except the flowers of B. gaudichaudii and C. elastica (staminate), in which the perianth is lacking. The staminate flower of B. gaudichaudii exhibits a bracteole enveloping the stamens. In monochlamydeous flowers the order of sepal initiation is helical or asynchronous. No petals are initiated. The calyx displays different degrees of synorganization being united only basally or along its entire extension. The sepals can have Lector and glandular trichomes or only Lector trichomes. Laticifers, phenolic and crystalliferous idioblasts occur in the sepal mesophyll. Stamens initiate concomitant with the pistillode in B. gaudichaudii and after initiation of the pistillode in M. tinctoria and M. nigra. In C. ilicifolia there is no pistillode and the stamens initiate after the sepals. The stamens show variation in filament shape and connective structure. The filament is inflexed in M. tinctoria and M. nigra and straight in the other species, although these structures are anatomically similar. The connective is expanded (except in M. nigra and C. ilicifolia) and has phenolic idioblasts. We conclude that the tiny flowers of these species result of two distinct ontogenetic pathways: absence of organs from the inception and by abortion, mechanisms that act to decrease the number of floral whorls as well as the number of organs in each whorl. (AU) | |
| FAPESP's process: | 14/07453-3 - Floral development of urticalean rosids |
| Grantee: | Simone de Pádua Teixeira |
| Support Opportunities: | Regular Research Grants |