Floral anatomy and development of Saxofridericia aculeata (Rapateaceae) and its taxonomic and phylogenetic significance Author(s): Renata C. Ferrari and Aline Oriani Source: Plant Systematics and Evolution, Vol. 303, No. 2 (February 2017), pp. 187-201 Published by: Springer Stable URL: https://www.jstor.org/stable/44854166 Accessed: 21-06-2021 11:49 UTC JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact [email protected]. Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at https://about.jstor.org/terms Springer is collaborating with JSTOR to digitize, preserve and extend access to Plant Systematics and Evolution This content downloaded from 86.59.13.237 on Mon, 21 Jun 2021 11:49:29 UTC All use subject to https://about.jstor.org/terms Plant Syst Evol (2017) 303:187-201 f CrossMark DOI 10.1 007/s00606-0 1 6- 1 36 1 -z ORIGINAL ARTICLE Floral anatomy and development of Saxofridericia aculeata (Rapateaceae) and its taxonomie and phylogenetic significance Renata C. Ferrari1©* Aline Oriani1 Received: 9 May 201 6 /Accepted: 13 October 2016 /Published online: 28 October 2016 © Springer- Verlag Wien 2016 Abstract Floral anatomy and development Keywordsof Saxofrid- Cluster analysis • Colleter • Monotremoideae • ericia aculeata Körn was studied in a comparative Postgenital intercarpellary fusion • Rapateoideae • approach to contribute to the understanding of the family. Saxofridericioideae Flowers at different developmental stages were analysed with light and scanning electron microscopy, and the nature of the exudate secreted by the floral trichomes was inves- Introduction tigated by histochemical tests. The anatomical character- istics observed in S. aculeata flowers were compared with Rapateaceae have a controversial phylogenetic position those from other Rapateaceae species by a cluster analysis in Poales. The family generally appears in an early (UPGMA). The dendrogram generated reflects the group- diverging position, closely related to Bromeliaceae and ings that emerged in phylogenetic molecular analyses, Typhaceae (Bremer 2002; Davis et al. 2004; Linder and highlighting the usefulness of floral anatomy for taxonomy Rudall 2005; Chase et al. 2006; Givnish et al. 2010). and for the understanding of infrafamilial relationships. However, in the most recent and largest molecular The exudate secreted by the trichomes has a polysaccha- phylogenetic analysis of Poales, based on rbcL and ndh¥ ride composition. Such trichomes (colleters) occur in the sequence data, Rapateaceae emerge as sister to Maya- sepals, petals, filaments and around the gynoecium; they caceae, close to Juncaceae, Thurniaceae and Cyperaceae, are initiated at mid-stage of floral development and are an although with low support (Bouchenak-Khelladi et al. apomorphy of the family. The flowers are pentacyclic, 2014). presenting three initially free sepals, petals, stamens and Rapateaceae occur almost exclusively in tropical South carpels that mature in a centripetal order. The connate America, except for the African and monotypie genus portion of the corolla, which is also adnate to the stamens, Maschalocephalus (Stevenson et al. 1998; Berry 2004). has a late development by zonal growth. Gynoecium for- The family comprises 17 genera and ca. 100 species, of mation is a combination of postgenital and congenital which around 40 are found in Brazil, mainly in the Amazon fusion processes. Data on floral organogenesis of Rap- region (Stevenson et al. 1998; Givnish et al. 2000, 2004; ateaceae are first reported here and support the early Berry 2004; Monteiro 2015). Rapateaceae are divided into diverging position of the family in Poales, close to three subfamilies and five tribes: Rapateoideae (Rap- Bromeliaceae. ateeae), Monotremoideae (Monotremeae) and Saxofrideri- cioideae (Saxofridericieae, Schoenocephalieae and Handling editor: Peter K. Endress. Stegolepideae) (Givnish et al. 2004). Saxofridericia is the only genus of the tribe Saxofrid- E Renata C. Ferrari ericieae and includes around 11 species (Berry 2004; [email protected] Givnish et al. 2004). The genus is characterised by glo- bose to hemispheric inflorescences completely enclosed 1 Departamento de Botânica, Instituto de Biociências, Universidade Estadual Paulista (UNESP), by two saccate involucral bracts, which are perforated by C. Postal 199, Rio Claro, SP 13506-900, Brazil the elongating sepal tips as the flowers develop (Berry £) Springer This content downloaded from 86.59.13.237 on Mon, 21 Jun 2021 11:49:29 UTC All use subject to https://about.jstor.org/terms 188 R. C. Ferrari, A. Oriani 2004). Saxofridericia Materials and methods aculeata Körn, is the most common species of the tribe, occurring in six South American countries, and Samples of isSaxofridericia distinguished aculeata were collected in the from the remaining Sax- ofridericia by Amazon Forestconstricted understory at Reserva Florestal Adolpho and spinescent leaves (Maguire 1958; Berry Ducke (Manaus,2004). Amazonas, Brazil). VouchersIt wereis herbaceous, with a short rhi- zomatous stem deposited at Herbarium that Rioclarense of thebears Universidade distichous long leaves and an axillary inflorescence Estadual Paulista (UNESP), Rio Claro Campus (Coan et peduncleal. (Maguire 1958; Berry 2004). 248). Flowers at different developmental stages were fixed Flower anatomy of Rapateaceae has been studied in in FAA 50 (37% formaldehyde, glacial acetic acid, 50% different genera of Rapateeae, Monotremeae and Ste- ethanol, 1:1:18 v/v) (Johansen 1940) and then transferred golepideae for taxonomie purposes by Oriani and Scatena into 70% ethanol. More than five individuals were analysed (2013). These authors highlighted the constancy of flower anatomically. anatomy at generic level and its importance to subfamilies, Morphological aspects of the flowers were observed tribes and genera identification. They also pointed to the under a stereomicroscope (Leica MZ6) and documented presence of floral secreting trichomes (colleters) as an using a digital camera (Canon, PowerShot S80). For the apomorphy of the family. Flowers of Rapateaceae are analyses under light microscopy, the material was dehy- known for having abundant amounts of mucilage covering drated in a n-butyl alcohol series, embedded in (2-hy- its floral buds and inflorescences (Maguire 1958, 1965; droxyethyl)-methacrylate (Leica Historesin Embedding Stevenson et al. 1998; Berry 2004); however, there are no Kit) (Gerrits and Smid 1983) and sectioned at 5-10 pm on studies characterising this exudate. a rotary microtome (Leica RM 2245). These sections were The floral architecture of angiosperms has been studied stained with periodic acid-Schiffs reagent (PAS) and under many different points of view, such as genomics, Toluidine Blue (Feder and O'Brien 1968) and mounted on genetics, morphology and anatomy, that combined are slides using Entellan (Merck). The following histochemical important to elucidate the floral evolution (Soltis et al. tests were performed: Toluidine Blue (O'Brien et al. 1964), 2002; Endress 1994, 2011). In addition, the study of Sudan IV for total lipids (Jensen 1962), periodic acid and flower development adds another dimension for the Schiffs reagent (PAS) for polysaccharides (Feder and understanding of phylogenetic relationships among O'Brien 1968), Coomassie Brilliant Blue for proteins groups, since it allows the identification of homologies (Fisher 1968), Ruthenium Red for pectins, potassium (Endress 1990; Tucker 1992, 1997). Also, the under- chloride (IKI) for starch grains, 10% aqueous FeCl3 for standing of initiation and post-initiation events during phenolic compounds, 5% tannic acid and 3% FeCl3 for floral morphogenesis can reveal fusion events during mucilage (Johansen 1940). Such tests were applied in compound organs formation (Kaplan 1968; Verbeke sections obtained from microtome and also in paradermal 1992). There are several studies on floral anatomy and handmade sections of sepals, petals, filaments and ovary. development of Poalean families (e.g. Ronse Decraene The handmade sections were mounted on slides with water et al. 2002; Sajo et al. 2004, 2007; Rudall et al. 2005; for documentation. The images were obtained with a Vrijdaghs et al. 2005, 2009; Sokoloff et al. 2009; Remi- microscope (Leica DM 500) equipped with a camera (Le- zowa et al. 2012; Reynders et al. 2012; Sajo and Rudall ica ICC 50), using the software LAS (Leica Application 2012), but for Rapateaceae, there is a lack of ontogenetic Suite version 3.0 2013). information. For the analyses under scanning electron microscopy, In this work, we analysed the floral anatomy and flowers at different developmental stages were dehydrated development of Saxofridericia aculeata (Saxofridericieae), in an acetone series, critical point-dried (Balzers CPD 030) aiming to characterise the species and describe, for the first and coated with gold (Balzers SCD 050 Sputter Coater). time, the nature of flower exudate and the flower devel- The samples were examined in a Tabletop Microscope opment in Rapateaceae. Considering that systematic stud- Hitachi (TM 3000) at the Laboratório de Microscopia ies and hypotheses on phylogenetic relationships among Eletrônica of Universidade Estadual Paulista (Sao Paulo taxa