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Abstract Detail



Reproductive Processes

Muñoz-Hernádez, Arelee [1], Figueroa-Castro, Dulce [2], Lozada Mellado, Monserrat [2], Almeida Silva, Briseida [2], Castañeda-Posadas, Carlos [3].

Relationship between perianth size and mating system in the Orchidaceae family.

Floral morphology is strongly associated with plant reproduction. Particularly, perianth traits are associated with plant reproductive aspects, such as pollination system, mating system and self-compatibility system. For instance, it has been acknowledged that self-compatible plants that self-pollinate, with a generalist pollination system usually have inconspicuous flowers with actinomorphic symmetry. Contrastingly, self-incompatible plants, that are outcross pollinated and have a specialized pollination system tend to produce large flowers with zygomorphic symmetry and a well-developed perianth. Therefore, strong differences in perianth size are common in plants with contrasting mating system, according with their dependence of pollinators for pollen transport. Although this pattern has been repeatedly documented in many angiosperm species, it has not been analyzed in some plant families such as Orchidaceae. Orchid flowers are strongly modified; they have a longest and more colored petal called labellum; an apparent bilabiate corolla given by the opposite organization of sepals and lateral petals relative to labellum; and androecium fused with gynoecium in a structure called gynostemium. Moreover, the presence of a rostellum (a gynostemium protuberance formed between anthers and stigma) prevents the deposition of pollen on the stigma favoring outcross pollination, whereas the lack of rostellum favors autogamy. Here, we evaluate the relationship between mating system and perianth size in plants within the Orchidaceae family. Digitalized herbarium specimens from 10 species with contrasting mating system (5 with rostellum= cross-pollinated; 5 without rostellum= self-pollinated) were used. Perianth traits (length, width, and area of dorsal sepal and labellum; mean length, width, and area of lateral sepals and petals; area of calyx, corolla, and the whole perianth; and inflorescence length) were measured on each of five specimens per species using the software ImageJ. Two-way ANOVA tests using mating system as fix factor and species as nested factor were applied for each variable. The analyses showed a lack of significant differences in all the perianth traits measured between orchids with contrasting mating system. However, for all the traits analyzed, a strong trend towards higher values in species with outcross mating system compared with the autogamic ones, was observed. The lack of significant differences between orchids with contrasting mating systems might be caused by the great diversity of taxonomic groups used in the analyses (2 subfamilies, 4 tribes, 8 genera). Future studies evaluating the relationship between mating system and flower size in orchids should control by phylogeny using more species from a low taxonomic category.


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1 - Benemérita Universidad Autónoma de Puebla, Maestría en Ciencias biológicas, Boulevard Valsequillo, Jardines de San Manuel, Puebla, Pue, 72570
2 - Benemérita Universidad Autónoma de Puebla, Laboratorio de interacciones ecológicas, Boulevard Valsequillo, Jardines de San Manuel, Puebla, Pue, 72570
3 - Benemérita Universidad Autónoma de Puebla, Laboratorio de Paleontología, Boulevard Valsequillo, Jardines de San Manuel, Puebla, Pue, 72570

Keywords:
orchids
rostellum
floral morphology
outcross-pollination
self-pollination.

Presentation Type: Poster
Session: P3, Reproductive Processes Posters
Location: Virtual/Virtual
Date: Wednesday, July 21st, 2021
Time: 5:00 PM(EDT)
Number: P3RP004
Abstract ID:499
Candidate for Awards:None


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