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One-seeded fruits in the core Caryophyllales: Origin and structural diversityтезисы доклада
- Авторы: Sukhorukov A.P., Krinitsyna A.A., Struwig M., Nilova M.V., Kushunina M.A., Devyatov A.G.
- Сборник: Functional plant anatomy: Proceedings of the International conference, dedicated to 90th anniversary of Gorn B. Kedrov (Moscow, September 16–21, 2013)
- Редактор: Тимонин Александр Константинович
- Тезисы
- Год издания: 2013
- Место издания: MAKS Press Moscow
- Первая страница: 169
- Последняя страница: 172
- Аннотация: The order Caryophyllales is a member of core eudicots (APG III) and comprises at least 12000 species distributed worldwide. Molecular results divide the order into two large clades. The first clade, which is often referred to as the core Caryophyllales or Caryophyllids, includes families in the traditional order circumscription (Caryophyllaceae, Cactaceae, Chenopodiaceae, Amaranthaceae, Nyctaginaceae, etc.). The second clade (the non-core Caryophyllales, or Polygonids) comprises Plumbaginaceae, Polygonaceae, Droseraceae and several smaller families. Around 30 families in the core Caryophyllales were only recently discovered or confirmed in their familial rank. The fruit characters of the core Caryophyllales are highly diverse. Among the multi-seeded fruits, capsules are common in Montiaceae, Molluginaceae, Aizoaceae, Stegnospermataceae, Limeaceae, Portulacaceae, Talinaceae, as well as in part of Lophiocarpaceae (Lophiocarpus), Caryophyllaceae and Amaranthaceae. The multi-seeded fruits can be indehiscent, berry-like, derived from ovule, receptacle, and supporting foliar structures (Cactaceae), or schizocarps splitting into one-seeded (e.g. Gisekiaceae) or many-seeded mericarps (Caryophyllaceae: gen. Wilhelmsia). One-seeded fruits are a distinctive trait of Chenopodiaceae, Microteaceae, Nyctaginaceae, Petiveriaceae, Rivinaceae, Seguieriaceae, Anacampserotaceae, Sarcobataceae, Simmondsiaceae, Basellaceae, Achatocarpaceae, Agdestiaceae, Didiereaceae, almost all Amaranthaceae s.str., and in a part of Caryophyllaceae and Lophiocarpaceae (Lophiocarpus). In most cases, the fruits are dry and indehiscent. Fleshy fruits (completely or partially) occur only in Achatocarpaceae, some Rivinaceae and Chenopodiaceae (especially in the tribe Anabaseae), and Amaranthaceae (Bosea, Deeringia, Pleuropetalum). In arid regions, the fruits can be enclosed in an anthocarp (e.g. bracts or a persistent perianth) which develops wing-like projections or tubercles, enabling long-distance dispersal (either anemochory or epizoochory). These foliar structures are sometimes coloured and contain water-accumulating tissue (Chenopodiaceae: a part of the gen. Blitum, Enchylaena; Basellaceae: gen. Basella) thus mimicking the fleshy pericarp. The anthocarp is often confused with the pericarp, and insufficient observations leads to morphological misunderstandings. Detailed anatomy and ultrastructure of the pericarp and the seed coat in one-seeded fruits are still poorly investigated. This is true not only for the small groups which lack data almost completely, but also for large families such as the Amaranthaceae or Nyctaginaceae. The Caryophyllaceae, however, has received more attention through studies concerning the evolutionary trends in their fruit anatomy. Based on the embryological data and formerly widely accepted, it was suggests that fruit/seed characters were simplified. Recently, the indehiscent or irregularly dehiscent fruits in Caryophyllaceae are considered as an ancestral trait characteristic for the basal clades Сorrigioleae and Paronychieae, with further radiation to the multi-seeded fruits in the majority of Caryophyllaceae (Plurcaryophyllaceae clade). In the present article, one-seeded fruits are mostly investigated with the following objectives (1) to investigate or ascertain the carpological characters of one-seeded fruits with implication to the recent taxonomy of the members of the core Caryophyllales; (2) to reconstruct the origin of one-seeded fruits and changes in some important carpological characters in different clades. Results and conclusions Amongst the core Caryophyllales, one-seeded fruits have risen multiple times in many clades, except in the ACPT-clade (Cactaceae + Portulaca and Talinum). The early diverging families might have had both dry, one-seeded, indehiscent fruits and capsules with several seeds. One of the first diverging core order families, the Caryophyllaceae, possesses both these fruit types (dehiscent capsules and indehiscent one-seeded fruits), with predominant occurrence of the latter type in Paronychieae and in a part of Polycarpaeae. In the Plurcaryophyllaceae clade, multi-seeded capsules have evolved in most of the species.. However, the reversion to one-seeded fruits is noted in some Plurcaryophyllaceae (especially in Acanthophyllum), although the pericarp topology is as in the other clade members with multi-seeded fruits. In total, 28 characters were found to describe all changes in the pericarp and seedcoat structure. To gain information for the molecular trees (ITS, rbcL and matK), the sequenses were taken from NCBI database (open access). Several characters were reconstructed. The undifferentiated, multi-layered pericarp seems to be an ancestral trait with reduction or obliteration of the pericarp layers in many lineages. However, some well-diversified families, especially a part of Amaranthaceae s.str. (Gomphrenoideae, Achyranthoids), Caryophyllaceae and Chenopodiaceae (Salsoloideae) are characterized by the differentiated pericarp in the upper fruit half and a simplified structure in the lower half. Although the diaspores in many species are dispersed anemochorously, the most common adaptations are connected with the floral parts enveloping the fruit, whereas distinct wing-like fruit outgrowths are rare and evolved only several times in Sarcobataceae, some lineages of Chenopodiaceae, and Seguieriaceae (formerly assigned as a part of Phytolacccaceae). Unique carpological characters of taxonomic importance that supports the familial level were discovered for Achatocarpaceae (polystarch grains in the seeds), Sarcobataceae (general pericarp structure), and Seguieriaceae (pericarp structure). Carpologically the Amaranthaceae s.str. and Chenopodiaceae differ in that the majority of the Chenopodiaceae lineages clearly have a tendency to evolve the seeds with horizontal embryo position that seems to be a unique trait among all the core Caryophyllales; and in contrast to Chenopodiaceae, a part of Amaranthaceae possess rhombic monocrystals in the pericarp. The U-shaped cells with fine crystalliferous content as a part of the pericarp are observed in Achatocarpaceae, Amaranthaceae, and Chenopodiaceae (AAC-clade). From the ‘raphide clade’, the largest family, Nyctaginaceae, demonstrates a diversity of anthocarps with similar simplified fruit and seedcoat organization, except in the basal clades (tribes Boldoeae and Colignonieae). The presence of the raphids that appears to be common in the vegetative organs of the family’s representatives is confirmed only for the unusual multi-layered, undifferentiated and parenchymatic pericarp of Bougainvillea. The presence of the albumin bodies in the fruit and seed covers, hardly noticeable one-layered pericarp and seed perisperm divided into two parts are the carpological peculiarities of Nyctaginaceae. The majority of the small families (Lophiocarpaceae, Microteaceae, Rivinaceae) do not show relevant differences in the pericarp structure, although some Rivina species are distinguished by the acicular outgrowths of the seedcoat testa, a rare trait also encountered in two Blitum representatives (Anserineae-Chenopodioideae). The hard seedcoat testa appears to be typical for the majority of the core Caryophyllales. In all the basal groups the seedcoat testa does not have the tannin-like substances in the outer cell walls and the vertically (radially) oriented stalactites are only found in some groups of Amaranthaceae and Chenopodiaceae, as well as in Boldoa (one of the basal representatives of Nyctaginaceae). The general trend of the seedcoat structure in many clades of the core Caryophyllales is the simplification and thinning of the testa layer. The straight embryo is plesiomorphic character within the Caryophyllids. The spirally coiled or annular embryo appears to be synapomorphy in the order.
- Добавил в систему: Сухоруков Александр Петрович