Unique tetrads of Epilobium luteum (Onagraceae: Onagreae) pollen from Alaska (original) (raw)
Related papers
Bitlis Eren University Journal of Science and Technology, 2021
In this study, pollen morphologies of eleven species of the Epilobium L. genus belonging to Onagraceae family were investigated under light and scanning electron microscopy. Solutions to taxonomic problems of these species were sought with palynological information. The characteristics of the genus Epilobium L. studied as a result of palynological studies are as follows: It has been determined that their pollen grains have tetrad, angulaperturate, 3-zonoporate (rarely 2,4 porate), suboblate and oblate-spheroidal pollen shapes, and have baculate, baculate-rugulate, and rugulate ornamentation.
Morpho-taxonomical studies of some Polyporate pollen grains
Pollen morphology of 24 species of 14 genera belonging to four families, viz., Amaranthaceae, Convolvulaceae, Malvaceae and Nyctaginaceae has been studied. The pollen grains of these taxonomically unrelated taxa, exhibit variation in colour, size, shape, exine ornamentation as well as in the number, position and character (NPC) of pores, but the pollen grains were usually polyporate and a few are polyzonocolporate. The pollen grains in the taxa of the family Amaranthaceae were small, non-spinous with polyporate exine, whereas, the pollen grains of taxa belonging to other three families were echinate. The maximum numbers of pores have been recorded in convolvulaceous pollens. Likewise, pollen grains of nyctagenaceous taxa can be distinguished from the pollens of other families on the basis of the size of pollen and spines. The pollens of the members of family Malvaceae exhibit different patterns of pore arrangements on the exine.
Pollen Morphology and Its Systematic Significance in the Ericaceae
Chapter 1: GENERAL INTRODUCTION Chapter 2: MATERIALS AND METHODS Chapter 3: POLLEN MORPHOLOGY AND ITS SYSTEMATIC SIGNIFICANCE 20 GENERAL POLLEN MORPHOLOGY OF THE ERICACEAE 20 Table 2-1: Some common pollen terminology. Terms are generally based on Punt et al. (1994). Apocolpium: A region at the pole of a zonocolpate pollen grain delimited by lines connecting the apices of the colpi (Fig. 2-2 A). Colpor(oid)ate: A compound aperture characterized by an ectoaperture, a distinct and/or indistinct endoaperture. Colporoidate: A compound aperture characterized by an ectoaperture, an indistinct endoaperture. Colpororate: A compound aperture characterized by an ectoaperture, a shorter lalongate (equatorially elongate) or lolongate (vertically elongate) endoaperture (Fig. 2-1). Colpus (L or 2f): An elongated aperture with a length/breadth ratio greater than 2 (Fig. 2-1). Colpus membrane: The aperture membrane of a colpus (Fig. 2-2 B). Costa (pl. costae): A thickening of the nexine/endexine bordering an endoaperture, or following the outline of an ectoaperture (Fig. 2-2 C). Decussate tetrad: A multiplanar tetrad of pollen grains arranged in two pairs lying across one another, the pairs (dyads) more or less at right angles to each other. Ectexine: The outer part of the exine, which stains positively with basic fuchsin in optical microscopy and has lower electron density TEM sections (Fig. 2-2 D). Endexine: The inner part of the exine which remains relatively unstained with basic fuchsin in optical microscopy and has a higher electron density TEM sections (Fig. 2-2 D). Endocrack: An irregular groove occurring in the inner surface of the nexine/endexine and readily apparent in acetolysed pollen (Fig. 2-2 E). Equatorial diameter (E or d): A line, lying in the equatorial plane, perpendicular to the polar axis and passing through it (Fig. 2-1). Exine: The outer layer of the wall of pollen, which is highly resistant to strong acids and bases, and is composed primarily of sporopollenin (Fig. 2-1). Heterodynamosporus tetrad (pseudomonad): All four pollen grains of the tetrad not of same size (Fig. 2-2 F). Intine: The innermost of the major layers of the pollen grain wall underlying the exine and bordering the surface of the cytoplasm. Isodynamosporus tetrad: All four pollen grains of the tetrad of same size (Fig. 2-2 G). Mesocolpium: The area of a pollen grain surface delimited by lines between the apices of adjacent colpi or the margins of adjacent pores (Fig. 2-2 H).
Aperture variation in the pollen of Nelumbo (Nelumbonaceae)
Grana, 2007
The evolutionary and developmental origin of tricolpate pollen is of great interest because pollen of this kind defines a major clade of angiosperms (eudicots), a clade that is also well supported by molecular data. We examined evidence that tricolpate and monosulcate pollen types are produced alongside each other in the anthers of Nelumbo flowers, as has previously been reported. Observations of pollen in situ within individual anthers revealed mainly tricolpate pollen produced in tetrahedral tetrads, but also a small percentage of clearly aberrant pollen grains that have a great variety of aperture configurations. Previously published evidence for tetragonal tetrads is not supported, and previously reported monosulcate grains are part of a continuum of variation among the aberrant grains in aperture number, position and form. Other eudicots show similar variability in their pollen apertures. The variation in the pollen of Nelumbo is not exceptional, and may not be more significant than variation seen in the other taxa with regard to the origin of the tricolpate and tricolpate-derived pollen characteristic of eudicots. Nevertheless further studies of aberrant pollen in Nelumbo and other eudicots, together with comparisons of pollen development in ''normal'' eudicots and closely related species that show radical, and developmentally fixed, reorganization of apertures and pollen polarity, may be helpful in understanding the processes that controlled the transition from the monosulcate to the tricolpate condition.
Grana, 2019
Astragalus is with nearly 3000 described species the largest genus of flowering plants. So far analyses of pollen characters have only been conducted for a few species of the groups within the genus. Here we analyse pollen grains of 22 species representative for Astragalus section Hymenostegis using scanning electron microscopy. We found the basic shape of the pollen grains to be oblate-spheroidal and apertures to be tricolpate as for other eudicots. The sculpturing pattern of the exine is micro-reticulate. Pollen grains show low morphological variation among different species of this section, but differences occur between sections of the genus. We conclude that the vast morphological differentiation that occurred during the rapid radiation of section Hymenostegis was not accompanied by comparable differentiation in pollen morphology.
Studies on pollen morphology ofRosaceae
Acta Botanica Gallica, 1994
Light and scanning electron microscope studies of pollen representing geo1era from all tribes of the Rosaceae reveal a variety of form and sculpturing. All genera examined produce radially symmetric isopolar monads. Most genera in subfamilies Maloideae, Prunoideae, and Sp/raeoideae produce tricolporate striate grains with large perforations in valleys between ridges. These tectate perforate grains have a chambered pore covered by arching ektexinal pore flaps. The ridge-and-valley pattern can vary from t-long ridges parallel to the colpus, to 2-medium to long ridges looping near the poles, to 3 • short weaving and crossing ridges. Striate perforate pollen occurs in tribes Dryadeae, Kerrieae, Roseae (operculate) and Rubeae of subfamily Rosoideae. in some Rubus species perforate and verrucate sculpturing occurs. Tribe Potentilleae (= Fragarieae) produces pollen with microperforations rather than typical perforations and most genera have an operculum. Coluria. Fallugia, Geum, Orthurus, and Wa/dsteinia of Dryadeae produce striate microperforate pollen, suggesting that they may belong in the Potentilleae. Filipendula (Uimarieae) is prominently verrucate. Tuberculate perforate sculpturing occurs in Cercocarpus, Cowan/a, and Purshia suggesting a natural group distinct frcm the rest of the family. The diverse Poterieae (= Sanguisorbeae) has mainly tricolporate and some hexacolporate (Sanguisorba) grains all with an operculum. Some genera (Agrimonia group) have striate pollen, but most have microverrucae and perforations. Within the tribe, a distinctive group of mainly south hemispheric genera (Acaena. Cliffortia, Cowania. Hagenia, Leucosidea, Margyricarpus, Polylepis, Tetrag/ochin) has tricolporate perforate pollen, often with a short colpus, sculpturing of macroverrucae and rugulae covered by micro~errucae. These pollen characteristics suggest a distinct evolutionary lineage. Re~ume.-L'etude en microscopie optique et electronique du pollen de genres representant toutes les tribus de Rosaceae revele une variate de formes et d'ornementations. Les pollens de tous les genres etudies son! des mona
Pollen morphology of the Rosaceae of Western Canada
Grana, 1988
This paper begins a systematic SEhl and Lhl study of the pollen grains of the Rosaceae in Western Canada with genera Agrimonia, Alclietnilla, Amelanchier, Arrrnciis, Cliamaerhodos, and Crataegus. The above genera have tricolporate-tectate pollen grains in monads. Agrimonia gryposepala and A. striata have distinct striate sculpturing perpendicular to the colpus. Alchemilla occidentalis pollen is psilate except in the colpus area which is microechinate. The exine is thickened in the intercolpium. Antncos sjlwsrer pollen is very small and exhibits a coarsely striate sculpture. Cl~amaerliodos erecta pollen has a characteristic protruding pore area with a fusiform operculum over the aperture. The sculpturing consists of patches of short ridges. Crataegirs and Amelanchier pollen have pores with a characteristic equatorial bridge or flaps when open. Dimensions of the grains vary with degree of distension. Amelanchier alnifolia pollen exhibits geographic variability. Native North American Crataegiis species: C. doirglasii, C. rotitndifolia and C. sirccirlerzta have pollen which exhibits morphological variability and requires more study. In the suney so far, surface sculpturing is the most distinctive feature and, in combination with characteristics of the pore area, seems to distinguish the types. A table of characters permits the pollen of most taxa studied to be identified using Lhl and SEhl
Comparative Pollen Morphology and Its Relationship to Phylogeny of Pollen in the Hamamelidae
Annals of the Missouri Botanical Garden, 1986
Data on pollen morphological features from 200 species in 20 families commonly included in the Hamamelidae and particular species in the Anacardiaceae and Salicaceae are presented in this paper. The basic descriptive analyses presented are derived from observations by light microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Thirty pollen characters showed some variability, and each of the species was scored for these characters. These data were analyzed and similarity cluster analyses were generated. Both an unweighted pair group and a complete linkage strategy dendrogram were produced. Three major clusters of families were defined, based on these analyses. Group I consists of Trochodendraceae, Cercidiphyllaceae, Eupteleaceae, Platanaceae, Hamamelidaceae (including Altingioideae), Eucommiaceae, and Myrothamnaceae. The Liquidambaroideae, Eucommiaceae, and Myrothamnaceae, while closest to Group I, can be viewed as intermediate between Groups I and II in complete linkage strategy and between Groups II and III in unweighted pair group strategy. Group IIâ€" consisting of Daphniphyllaceae and Fagaceae (excluding Not hofagus)â€" has a closer phenetic relationship to Group I than Group IIL Group III is the largest of these groups: it consists of Ulmaceae, Cannabaceae, Juglandaceae, Rhoipteleaceae, Betulaceae, Casuarinaceae, and Myricaceae. The Balanopaceae and Nothofagus are somewhat isolated and peripheral entities but hold together in both linkage strategies. Thirty pollen characters of 78 taxa were analyzed using PAUP to produce a cladistic tree. The outgroup used was Tetracentron, Three phylogenetically related groups sorted out, which are the same as those already recognized in the Groups I, II, and III mentioned above. Group I occurs at the base of the tree (primitive), and Group II occurs as intermediate between Groups I and III (derived). In general, these data support the relationships suggested by Barabe for the Hamamelidae, based upon vegetative and floral features and the classification of Cronquist. Leitneriaceae This survey ofpollen in the Hamamelidae was by Cronquist (1981), representing over 200 initiated with three primary goals in mind: (1) species (Didymelaceae, Urticaceae, Moraceae, morphological and Cecropiaceae are excluded from the cladistic assessing the relationships of fossil-dispersed and phenetic analyses). In addition, pollen data pollen with possible hamamelidaceous affinity, from the Anacardiaceae and Salicaceae are in-(2) to assess at which taxonomic level pollen eluded in the analysis. characters of extant hamamelidaceous taxa are In a survey as broad as that presented here, it useful in determining taxonomic position, and is often difficult to decide which taxa to include (3) to assess the phylogenetic relationships of taxa Members within the Hamamelidae as elucidated by pollen been placed in a number of subclasses, and a morphology and ultrastructure. comprehensive pollen survey of all the families To achieve these ends we used pollen data of the different classifications was not attempted [transmission electron microscopy (TEM) and here. We scanning electron microscopy (SEM)] from pub-system as a starting point and introduced into lished literature and added pollen data from 42 our analysis selected taxa from other subclasses previously uninvestigated taxa. We have amassed that have been suggested to be phylogenetically pollen data from 20 of the 24 families recognized related (e.g., Thome, 1973). » We wish to give special thanks to Robert Schwarzwalder for his many helpful suggestions and his consultation on the cladistic and phenetic analyses. We also thank Karl Longstreth, Linn Bogle, and Greg Anderson for their review of the manuscript. We thank Thomas Delendick of the Brooklyn Botanic Garden for material of the Eucommiaceae and the U.
Pollen morphology of six species of subfamily
2016
The pollen morphological characters of 6 species belonging to 4 genera of the subfamily Stachyoideae (Lamiaceae) growing naturally in Saudi Arabia were investigated with the aid of light microscope (LM) and scanning electron microscope (SEM), to find new features that might increase knowledge of pollen morphology of the species, and also to help the taxonomic characterization of the Stachyoideae genera. The morphological characters studied were size, shape, tectum surface ornamentation, number and type of the colpi. The study indicated that the average size of the pollen was different among the species since the smallest size was that of Nepeta deflersiana (P = 25.2 ± 2 and E = 15 ± 3) while the largest size was that of Salvia aegyptiaca (P =36.5 ± 2 and E = 30.3 ± 2). Pollen shape is spheroidal to sub-spheroidal or prolate. The fine structure of the exine of pollen was slightly different among investigated species. The number and type of colpi of the pollen in species studied were 6-zonocolpate type except those of N. deflersiana and Otostegia fruticosa ssp. schimperi having 3-zonocolpate.