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Anatomical diversity and evolution of anthocarp in Nyctaginaceaeтезисы доклада
- Авторы: Sukhorukov A.P., Nilova M.V., Zaika M.A., Moore M., Douglas N.A.
- Сборник: 23rd Symposium on ‘Biodiversity and Evolutionary Biology’ of the German Botanical Society
- Тезисы
- Год издания: 2016
- Место издания: Munich
- Аннотация: Nyctaginaceae is one of the most diverse families in the core Caryophyllales, comprising approximately 400 species. The most indicative character of the family is a persistent accessory fruit, the “anthocarp”, derived from a uniseriate perianth. The anatomy of the anthocarp is poorly studied, and its evolution has not been traced. 140 species from 28 genera were included in an anatomical analysis. Cross-sections of the anthocarp were made by hand or by a sliding microtome. Scanning electron microscopy (SEM) is used to describe the trichomes on the anthocarp surface or to photograph of the raphides. We conducted phylogenetical analyses using Maximum likelihood and Bayesian analyses based on plastid ndhF sequences using 76 samples for 70 species. The parsimony reconstructions of ancestral states for two characters tightly connected to dispersal (presence of the mucilage in the anthocarp and evolution of winged anthocarp) are provided for the first time. The anthocarp anatomy is very diverse in Nyctaginaceae. The representatives of the earliest-diverging clades Leucastereae and Boldoeae possess a calyx-like anthocarp. In the other tribes, the mostly colored upper perianth part imitates a deciduous “corolla” and the lower accrescent perianth forms the “true” anthocarp that is characteristic for the remaining tribes of Nyctaginaceae, especially in tribe Nyctagineae. The simple anthocarp anatomy of Leucastereae, Boldoeae and Colignonieae contrasts with a diverse set of adaptations that appear in to be evolving dynamically in Bougainvilleae and Nyctagineae. The so-called “glands” in Nyctagineae (Commicarpus) or Pisonieae are actually emergences resulting from the protrusions of the anthocarp mesophyll. Winged anthocarps have independently evolved several times in the family (in some Colignonieae, Bougainvilleae, Pisonieae, and Nyctagineae). The origin of the mucilage in the anthocarp (mostly produced in the rib areas in the subepidermal layers of the anthocarp) is common in tribe Nyctagineae, which often grow under xerophytic conditions. This character evolved at least four times in Eurasian members of Commicarpus, Acleisanthes longiflora, a part of Mirabilis (M. albida, M. laevis, M. multiflora, M. nyctaginea, M. oxybaphoides, M. violacea), and in a large clade comprising of Anulocaulis, Boerhavia, Nyctaginia, and Cyphomeris. The loss of mucilage occurred in Okenia, which has unique hypogeal fruit maturation. Taxonomically, the anthocarp anatomy is considered diagnostic of genera. Our phylogenetic perspective incorporating most genera and diversity in anthocarp structure gives increased power to study details of homology between anthocarps with different dispersal modes, and previously overlooked differences between seemingly similar morphologies derived through clear convergent evolution. This work has taxonomic implications in large difficult clades (e.g. Boerhavia, tribe Pisoniaeae).
- Добавил в систему: Сухоруков Александр Петрович