This article was downloaded by: [72.199.208.79] On: 25 May 2012, At: 23:08 Publisher: Taylor & Francis Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK Grana Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/sgra20 Pollen ultrastructure of the Pontederiaceae Michael G. Simpson a a Department of Biology, San Diego State University, San Diego, California, 92182, USA Available online: 05 Nov 2009 To cite this article: Michael G. Simpson (1987): Pollen ultrastructure of the Pontederiaceae, Grana, 26:2, 113-126 To link to this article: http://dx.doi.org/10.1080/00173138709429941 PLEASE SCROLL DOWN FOR ARTICLE Full terms and conditions of use: http://www.tandfonline.com/page/terms-and-conditions This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. The publisher does not give any warranty express or implied or make any representation that the contents will be complete or accurate or up to date. The accuracy of any instructions, formulae, and drug doses should be independently verified with primary sources. The publisher shall not be liable for any loss, actions, claims, proceedings, demand, or costs or damages whatsoever or howsoever caused arising directly or indirectly in connection with or arising out of the use of this material. Grana 26: 113-126, 1987 Pollen ultrastructure of the Pontederiaceae Evidence for exine homology with the Haemodoraceae MICHAEL G. SIMPSON Simpson, hl. G. 1987. Pollen ultrastructure of the Pontederiaceae. Evidence for exine homology with the Haemodoraceae. - Gram 26: 113-126, 1987. Uppsala 25 June 1987. ISSN 0017-3134. Pollen of eight genera and species of the Pontedcrixeae u.1~;I>* rigdcd d\iIig SEhl and TEhl in order to elucidate interrelationships to uthei monocot families. All examined Pontederiaceae are diaperturate with furrow-shaped apertures and have a distinctly verru- cate non-apertural exine sculpturing (except Ponrederin, which is psilate to scabrate in sculpturing). Among investigated taxa the exine wall architecture exhibits a gradation between: (1) a 1-layered exine composed of laterally appressed, basally fused baculate elements, (2) a 2-layered exine, the outer layer composed of laterally appressed baculate elements and the inner forming a thin layer or composed of discrete papillate elements, and (3) a tectate-columellate exine, differing, however, from a typical tectate-columellate architecture by having short, narrow columellae and generally baculate tectal elements. Of the palynologically investigated families presumed closely related to the Pontederiaceae, only members of the tribe Haemodoreae of the Haemodoraceae have a venucate sculptur- ing similar to that of most Pontederiaceae. In addition, the exine architecture of the non- tectate-columellate genera of the Pontederiaceae is strikingly similar (and presumably homologous) to members of the family Haemodoraceae. It is proposed that the similarities in pollen exine sculpturing and architecture betueen the Pontederiaceae and Haemodora- ceae are so by homology (common evolutionary origin) and constitute evidence for the close relationship and possible sister-group status of these families. hficliael G. Simpson, Department of Biology, Sari Diego Sfnte Uniuersiry, Sun Diego, California 92182, USA. (hfanirscripr received 7 Aiigrtsr 1985, revised version nccepred 21 hlay 1986) Downloaded by [72.199.208.79] at 23:08 25 May 2012 The Pontederiaceae (Pickerel Weed family) are a or ovary. A similar classification of the Pontederia- small family of monocotyledons, consisting of 7-9 ceae within the Liliales was proposed by Schwartz genera and approximately 30 species. Diagnostic (1930), Hamann (1964), Cronquist (1981), and morphological features of the family are an aquatic Takhtajan (1980), with Harnann (1966) concluding habitat; rhizomatous stems; alternate, distichous, that the familiy is most closely related to the family petiolate (and often ligulate) leaves; actinomorphic Philydaceae. Dahlgren & Clifford (1982) treated the to zygomorphic flowers with trimerous, sympeta- Pontederiaceae as the monofamilial order Ponteder- lous, hypogynous flowers; and a capsular fruit with iales of their Liliiflorae, “with closest relatives I-numerous endospermous seeds per locule. among the Philydrales and Haemodorales”. Dahl- Concepts as to the affinities of the Pontederia- gren & Rasmussen (1983), in a phylogenetic analy- ceae have (like most taxonomic groups) varied. sis of the monocotyledons, argued that the Ponte- Hutchinson (1934, 1959, 1973) placed the Ponteder- deriaceae, Haemodoraceae, and Philydraceae iaceae in his order Liliales (which also included the should be transferred from the Liliiflorae to the Liliaceae, Tecophilaeaceae, Trilliaceae, Smilaca- Commeliniflorae, based on the occurrence in these ceae, and Ruscaceae), based primarily on the gen- taxa of hypothesized apomorphic features, includ- eral possession in the order of an actinomorphic ing UV-fluorescent cell wall-bound compounds and membranous perianth, 6 stamens, and a superi- (Harris & Hartley 1980) and seeds with a starchy 8- 878362 Grana 26 I14 hf. G. Sittipsoti endosperm. The authors suggested that the Ponte- sputter coated (ca. 200 A thickness) with gold/palladium deriaceae, Haemodoraceae, and TyphaceaelSpar- (60/40),and viewed with a JEOL JShI-SI SEhl. ganiaceae together comprise a monophyletic group, For TEhl analysis, whole anthers were fixed in 4% glutaraldehyde for 2 hours, rinsed several times in 0.1 hi the whole assemblage being the sister-group of the Sorensen’s phosphate buffer, and post-fixed in 2 % OSOJ Philydraceae. for 1 hour. After two rapid dH2O rinses and dehydration Palynological studies of the Pontederiaceae pub- 10 100% ethanol, the material \ms infiltrated in a series of lished to date are scanty. Rao & Rao (1961) de- increasing concentrations of Spurr’s resin (Spurr 1969), placed in a BEEhl capsule, and polymerized 8-12 hours at scribed the pollen of hfotzochorin uqitinlis and 70°C. Sections ca. 85 nm thick were prepared using a Eich\iortzin crassipes as “slightly semilumar and . .. diamond knife on a Cambridge-Huxley or Reichert ultra- two sulculate or one sulculate, reticulate.” Erdtman microtome, and mounted on uncoated 200 mesh grids. (1966), in a review of the then current literature and Preparations wcre post-stained with filtered 4% uranyl original observations of one species, Potirederiu aceta1ein50%ethanol(15 rninutes)and2%leadcitrate(7 min) and viewed with a Siemens Elmiskop 101 or a Zeiss cordutu L., described the pollen of the family as EM9S-2 TEM. “2(-3)-sulculate, longest axis (38-)51-71 pm. Sexine Light microscope studies (not illustrated) were made to as thick as nexine or thicker, sometimes +/- areo- determine pollen size and to confirm aperture number. loidate. S-pattern: LO.” Pollen samples uere acetolyzed in standard 9: I acetic anhydride: sulfuric acid solution at 55°C for 8-12 hours. The purpose of the following study is to charac- After rinsing in H20 and 50% glycerin, the samples were terize, using SEM and TEM, the basic pollen mor- mounted in glycerin jelly. Mean maximum dimension of phology and wall ultrastructure of members of the pollen grains (determined from measurements of 50 Pontederiaceae and to note similarities and differ- grains) is indicated in parentheses below. ences with other monocot families in assessing phy- logenetic relationships. Of particular interest are possible indications of a close relationship of the RESULTS Pontederiaceae to the Philydraceae, as proposed by Eichhortziu crussipes (Mart.) Solms. - Pollen Hamann (1966), or to the Haemodoraceae, as pro- grains (47 Iim) diaperturate, apertures furrow- posed by Dahlgren & Rasmussen (1983). shaped (Fig. 1 A, C). Sculpturing of non-apertural region venucate, that of apertural region psilate (Fig. 1 B). Non-apertural exine composed of short MATERIALS AND METHODS baculate elements which are laterally appressed Pollen samples were largely obtained from herbarium and basally fused (Fig. 1D). Exine of apertural sheets. Anthers from dried herbarium specimens region absent (Fig. E). Intine not clearly ob- (“DRIED”) were re-expanded in 10% Aerosol OT for lC, one week, followed by several H20 rinses. Flowers from served in material examined. field collections were fixed in either formalidacetic acid alcohol (“FAA”) or in a solution of 4% glutaraldehyde Heterutitheru reniformis R. & P. - Pollen grains Downloaded by [72.199.208.79] at 23:08 25 May 2012 and 4% formalin in 0.1 hl Sorensen’s phosphate buffer (45 pm) diaperturate, apertures furrow-shaped (Fig. (“GLUT”). The following 8 taxa were examined: Eicli- horniu crussipes (hlart.) Soh“DRIED” - D. B. Zobel 2A, H). Sculpturing of non-apertural region verm- 20020 (DUKE); Heternntheru renifornlis R. & P. cate, that of apertural region psilate with numerous “GLUT” - M. G. Simpson 4V11182A (SDSU); Hydro- scattered, minutely verrucate elements (Fig. ZA, thrir gnrdneri Hooker f. “DRIED” - 0. Fontenele (US); B). Non-apertural exine usually composed of an hfonochoriu uaginulis (Burm. f.)Presl. ex Kunth “DRIED’ irregular foot-layer and short columellae, each - C. J. Saldanha 16106 (US); Pontederiu cordufa L. “FAA” - M. G. Simpson 20V1182A (SDSU); Reirssia bearing a