Exine Sculpture Research Articles

Systematic Importance of Pollen Morphology of Some Plants of (Lamiaceae)

<p>Pollen morphology of seven taxa belonging to Lamiaceae and common used as medicinal plants were examined by light (LM) and scanning electron microscopy (SEM).<em> Thymus vulgaris</em> L.<em>, Mentha longifolia</em> (<a title="Carolus Linnaeus" href="https://en.wikipedia.org/wiki/Carolus_Linnaeus">L.</a>) <a title="William Hudson (botanist)" href="https://en.wikipedia.org/wiki/William_Hudson_(botanist)">Huds.</a> Mentha<em> spicata L.</em>, <em>Ocimum basillicium L.</em>, <em>Salvia elegans </em>Vahl<em>, Salvia farinace</em><em>a</em> Benth, and<em> Salvia splendens</em> Sellow ex Roem. and Schult. Pollen morphological characteristics are provided for these taxa. Among the studied taxa, <em>Mentha longifolia</em> has the smallest pollen grains, and <em>Ocimum basillicium</em> possesses the largest ones. The main shape of pollen grains in the most taxa suboblate, oblate – spheroidal or prolate–spheroidal. However subprolate are recorded for <em>Salvia elegans</em>. The grains are hexacolpate in all taxa, but in <em>S.</em><strong><em> </em></strong><em>farinacea</em> octacolpate pollen was found. Three distinct exine sculpturing exist, reticulate–perforate the common type, also reticulate, granulate and bi-reticulate. However, the fine details are characteristic to differentiate between the pollen species. Exine is microreticulate in case of <em>S</em>. <em>elegans</em> and <em>S.</em><strong><em> </em></strong><em>farinacea</em>, but reticulate-foveolate in case of S<em>. splendens</em>. As well as, the presence of holes on colpus membrane ornamentation can be used as a taxonomic tool for sectional division between. <em>S. </em><em>elegans</em> from <em>S</em><em>. splendens</em> is clearly distinct from the other taxa examined by its characteristic pollen morphology. </p>

Pollen morphology of Crotonoideae (Euphorbiaceae) from Seasonally Dry Tropical Forests, Northeastern Brazil

Crotonoideae is a subfamily of Euphorbiaceae, a plant family that is characterized by the presence of laticifers and pollen grains with Croton pattern exine. We analysed 48 species of Crotonoideae from Seasonally Dry Tropical Forests within Caatinga vegetation aiming to contribute to the pollen morphology of this subfamily, focusing on endemics to these forests. Pollen samples were obtained from specimens of the herbarium. Pollen grains were acetolyzed, measured, photographed and described using light and scanning electron microscopy methods. Three pollen types and seven subtypes were recognized based on aperture type, polarity, shape, size and details of the exine sculpture. The exine ornamentation and the type and number of apertures are the most important characteristics for recognizing genera in Crotonoideae. Inaperturate pollen grains with surface pila plicate were observed in representatives of Croton and Jatropha; 4–8 pantoporate pollen grains and a 3-colpate one with psilate pila were observed in Cnidoscolus, and 10–22 pantoporate pollen grains with rugulate pila were observed in Manihot. Due to the high diversity of Crotonoideae pollen morphology, we highlighted its eurypalynous properties, in addition to its taxonomic relevance, for the identification of groups.

Pollen morphology in selected Cupressaceae Gray. and Sciadopityaceae Luerss. species in an experimental culture

Pollen grains of Cunninghamia lanceolata, Cryptomeria japonica and Sciadopitys verticillata were exam- ined by light and scanning electron microscopy. The pollen grains were non-saccate, generally oblate-sphe- roidal, spheroidal, prolate-spheroidal or subprolate. The pollen grains had papillae of different sizes and shapes on the distal face. The papillae were more conspicuous in C. japonica than in C. lanceolata. The pollen exine sculpture in the proximal view was verrucate-granulate and verrcucate with microechinate supras- culpture in SEM. The surface of the exine was covered with echinate orbicules in Cupressaceae species. There were some differences in the size of the verrucae, perforation on the proximal surface and distal face between S. verticillata pollen grains and other species. This study of the pollen grain morphology provided some important new data which have not been reported in literature so far.

Morphology, Anatomy and Palynology of Turkish endemic species Haplophyllum myrtifolium, H. vulcanicum & H. megalanthum (Rutaceae) and their systematics implications

Haplophyllum is one of the taxonomically difficult genera in the Rutaceae. Three Turkish endemic species of Haplophyllum, namely Haplophyllum myrtifolium, H. vulcanicum and H. megalanthum, have similar morphological features, therefore identification of the species are extremely difficult. In the present study, morphological, anatomical and palynological characteristics of the species are examined in order to understand the usefulness of these characteristics for systematics purposes. Morphological characteristics of leaves and corollas, absence/or presence of glandular hairs on the stem and inflorescence, expansion form of filaments and ovarium appendage are useful for specific delimitation among the species. Anatomical characters such as number of cortex layers and sclerenchymatic cell layers in stem, size of the vascular bundle in the midrib provide information of taxonomical significance. In addition, exine sculpturing pattern of pollen grains can be used for taxonomic purposes.

Pollen morphology of the genus Lamium L. (Lamiaceae) and its systematic implications

This is the first comprehensive palynological investigation of the genus Lamium. The pollen morphology of 48 taxa (including species, subspecies and varieties) of the genus Lamium was investigated and documented using light microscopy (LM) and scanning electron microscopy (SEM). Lamium pollen is small to medium sized (P=21.65–39.96μm), oblate-spheroidal to subprolate in shape and tricolpate. Three major exine sculpturing patterns (reticulate, granulate and microreticulate) were observed. The results indicated that the exine sculpturing pattern of Lamium is systematically informative at sectional level, but not at the species and infraspecific levels. In the present study, the palynological data are compared with available phylogenetic studies to evaluate the systematic value of pollen characters in the genus. Analysis show that; (1) Mennema's infrageneric classification is partly corroborated by our palynological data, (2) recent phylogenetic analysis on the genus and our results are partly corroborated, and (3) pollen morphology supports the inclusion of L. galeobdolon (=Galeobdolon), L. orientale and L. multifidum (=Wiedemannia) in Lamium. (4) Variation in exine sculpturing pattern have systematic importance particularly at sectional level.

Pollen morphology and its taxonomic significance in the genus Bomarea Mirb. (Alstroemeriaceae) - II. Subgenus Bomarea

Pollen morphology of 52 species (out of c. 79) of the Bomarea subgenus Bomarea was examined using light microscopy and scanning electron microscopy (SEM), or using SEM alone. The studied species of Bomarea were stenopalynous, characterized by large, oblate, monosulcate monads with reticulate exine sculpture in most species. Wide variation was observed in quantitative palynological features. The studied taxa were divided into four major groups based on exine ornamentation observed under SEM: microreticulate, reticulate, coarsely rugulate, and psilate-perforate. The reticulate exine sculpture may be a plesiomorphic character state for the genus Bomarea, and the coarsely rugulate and finely rugulate-perforate or psilate-perforate exine sculptures may have evolved independently more than once. In agglomerative hierarchical clustering (AHC) analyses of the genus Bomarea using quantitative pollen data, the studied species were distributed in either two (similarity-based) or four (dissimilarity-based) major clusters. Neither the recent molecular phylogenetic analyses nor the AHC analyses of Bomarea have recovered clades/clusters that represent traditionally recognized subgeneric taxa for the genus. Therefore, the most reliable infrageneric classification of Bomarea can be achieved by combining morphological, palynological, and molecular data from more extentive sampling of all the species.

Pollen morphology of Callicarpa L. (Lamiaceae) from China and its systematic implications

Pollen morphology of 36 species and 9 varieties of Callicarpa L. (Lamiaceae) from China was investigated through scanning electron microscopy. Pollen grains of the genus are monads, radiosymmetric and tricolpate, mainly medium in size, spheroidal (rarely subprolate, prolate or suboblate) in equatorial view and (sub) circular or rounded triangular in polar view. The edge of colpus is thin, perforate or thickened but imperforate and the colpus membrane of the investigated taxa is usually uneven (sunken or raised), with finely/coarsely granular or irregular striation. Four different ornamentation types are delimited on the basis of exine sculpturing: (1) coarsely reticulate; (2) microreticulate; (3) rugosely reticulate and (4) rugulate reticulate. The results do not support the traditional infrageneric classification of Callicarpa which is based on stamen characters. However, pollen characters provide evidence to support Callicarpa as the sister to the Australian subfamily Prostantheroideae, a relationship previously suggested by molecular phylogenetic analyses.

A diverse pollen assemblage found on Friisicarpus infructescences (Platanaceae) from the Cenomanian–Turonian of Kazakhstan

Pollen grains found on, or within, pistillate reproductive structures are described for numerous gymnosperms and angiosperms. Attribution of these pollen grains to the macrofossils is often risky and requires additional evidence. This study, based on the material from the Cenomanian–Turonian of Kazakhstan, is the first to document in detail different types of pollen adhering to platanoid infructescences of Friisicarpus sarbaensis. Infructescence parts were examined under SEM in search of pollen. Pollen grains were removed from SEM stubs and studied with LM and TEM. About 250 pollen grains adhering to infructescence axes and carpels were studied; they are small, reticulate (rarely foveolate), tricolpate or tricolporate, and columellate. At least nine pollen types have been distinguished based mainly on the details of the exine sculpturing. The exine ultrastructure was characterized for four prevailing types. Considering pollen morphology and ultrastructure, three types were shown to be produced by platanoids and one was probably ranunculid. Other pollen types are harder to refer to a certain group, though one of them probably belongs to Hamamelidaceae and another one shows exine sculpturing similar to Chloranthaceae pollen. One of the types prevails (about 170 pollen grains) and resembles pollen found on inflorescences of other Friisicarpus species, so we consider that this type was produced by the parent plant. Pollen grains of another type are identical to pollen of Sarbaya radiata from the same locality. The diversity and abundance of different pollen types of the similar size and sculpture found on the infructescences of Friisicarpus sarbaensis favour entomophily of this plant but challenge specific plant-insect specialization.

Pollen morphology and its taxonomic significance in the genus Bomarea Mirb. (Alstroemeriaceae) - I. Subgenera Baccata, Sphaerine, and Wichuraea

Pollen morphology of 24 of the 33 species of three Bomareasubgenera, Baccata, Sphaerine, andWichuraea, was examined by light microscopy (LM) and scanning electron microscopy (SEM), or SEM alone. The studied species ofBomarea were stenopalynous, characterized by large, monosulcate monads with reticulate exine sculpture in most species. Opercula-like structures were present on the sulcus in B.huanucoand B.involucrosa. Differences in pollen size, exine thickness, and exine sculpture were observed. The studied taxa were divided into four major groups based on exine ornamentation observed under SEM: microreticulate, reticulate, coarsely rugulate, or finely rugulate-perforate. Pollen characters alone did not appear to correlate clearly with the current subgeneric classification of Bomarea, but they may have some taxonomic utility below the subgeneric level. The most reliable infrageneric classification of Bomarea can be achieved through combined analyses of morphological, palynological, and molecular data from larger samples of specimens of all the species.

Pollen morphology of tribesAptosimeaeandMyoporeaesupports the phylogenetic pattern in early-branchingScrophulariaceaerevealed by molecular studies

Abstract Mosyakin S. L. & Tsymbalyuk Z. M.: Pollen morphology of tribes Aptosimeae and Myoporeae supports the phylogenetic pattern in early-branching Scrophulariaceae revealed by molecular studies. — Willdenowia 45: 209–222. 2015. — Version of record first published online on 15 July 2015 ahead of inclusion in August 2015 issue; ISSN 1868-6397; © 2015 BGBM Berlin. DOI: http://dx.doi.org/10.3372/wi.45.45207 Pollen morphology of six species representing three genera of tribe Aptosimeae and six species representing two genera of tribe Myoporeae (Scrophulariaceae) is described and illustrated using light microscopy (LM) and scanning electron microscopy (SEM). Pollen grains in Aptosimeae are 3-syncolporate, prolate, sometimes oblate-spheroidal in shape; mainly medium-sized, occasionally in some taxa small; exine sculpture striate, rarely with microperforations and small granules. Pollen grains in Myoporeae are 3-colpate-diorate, spheroidal, rarely oblate-spheroidal or prolate in shape; mainly medium-sized, occ...

Pollen Morphology of Pinus mugo Turra × Pinus sylvestris L. Hybrids and Parental Species in an Experimental Culture

Abstract Pollen grains of Pinus mugo, P. sylvestris and P. ×rhaetica (= P. mugo × P. sylvestris) were examined by light and scanning electron microscopy. The pollen grains were bisaccate and monosulcate. The corpus-saccus attachment was distinct. The pollen corpus exine sculpture was verrucate-rugulate and deeply sculptured. The surface of the tectum was covered with small grana and it was perforate. The saccus sexine ornamentation was reticulate and irregularly perforate. The tectum surface characters in the proximal and distal view of the corpus and saccus were less variable and they did not provide good criteria to identify the species under study. However, some differences were observed in the size of elevation on the corpus between pollen grains of the same species and between the parental species. This study of the pollen grain morphology of the corpus and saccus provided some important new data.

Morphological studies of the pollen grains for some hydrophytes in coastal Mediterranean lakes, Egypt

The pollen grains of forty species of the aquatic flowering plants (6 floating, 6 submerged and 28 emergent species) naturally growing in the four coastal Mediterranean lakes of Egypt were investigated during January–August 2012. These species belong to 17 families. Morphologically, the investigated pollen grains are mostly prolate-spheroidal, spheroidal or triangular, rarely prolate or elongated, tectum psilate, granulate, reticulate or microechinate. On the basis of aperture types pollen grains of most families are grouped under three distinct types, namely colporate, colpate and porate. On the other hand, pollen grains of some families e.g. Cyperaceae, Juncaceae, Potamogetonaceae and Ruppiaceae are inaperturate. It is worth to stating that from a phylogenetic and evolutionary point of views, polarity, symmetry, apertural types and exine sculpturing are the most important characters to differentiate between the different pollen types. The identified pollen grains, conserved in the herbarium of Botany Department, Faculty of Science, Mansoura University, Mansoura, Egypt, as reference key pollen in the northern lakes for palynologists, ecologists, taxonomists etc.

Pollen diversity among the inconstant male Ochradenusbaccatus delile populations in Egypt

In Egypt, Resedaceae is represented by 14 species belonging to five genera, genus Ochradenus is among them represented by one species (O. baccatus Delile). The studied Ochradenus baccatus populations collected from Wadi Degla, Egypt revealed that O. baccatus is gynodioecious species, with female individuals that are constant in sex expression and males that exhibit great variation in functional gender. The field study revealed the presence of inconstant male of O. baccatus in different forms ranging from high fruit-producing to low or nonfruit producing forms with two intermediate forms. The pollen morphology of all the four forms was examined using LM and SEM. This study is the first dealing with pollen grain morphological diversity within different O. baccatus populations, representing model of the inconstant male of a gynodioecious species. Generally, the examined Ochradenus baccatus pollen grains appeared under SEM as 3-colporate, isopolar, radiallysymmetrical, with reticulate exine sculpturing. This study revealed the presence of a variability in pollen size, shape, aperture and exine sculpturing in different forms. The polymorphic pattern observed in inconstant O. baccatus male populations in Egypt was attributed to internal factors, the polyploidy phenomenon was among them and the external factors were excluded.

Pollen morphology of the southern African tribeTeedieae, an early-branching lineage of crownScrophulariaceae

Mosyakin S. L. & Tsymbalyuk Z. M.: Pollen morphology of the southern African tribe Teedieae, an early-branching lineage of crown Scrophulariaceae. — Willdenowia 45: 65–75. 2015. — Version of record first published online on 13 March 2015 ahead of inclusion in April 2015 issue; ISSN 1868-6397; © 2015 BGBM Berlin-Dahlem.DOI: http://dx.doi.org/10.3372/wi.45.45107The pollen morphology of seven species representing four genera of the tribe Teedieae (Scrophulariaceae) is described and illustrated using light microscopy (LM) and scanning electron microscopy (SEM). Two major pollen types, 3-colporate and 4-colporate, are recognized by aperture types. Within these pollen types, subtypes are distinguished based on exine sculpture, colpi, colpus membrane, and endoaperture characters. Within type I (3-colporate), three subtypes are recognized: Ia — sculpture psilate, rarely with microperforations; Ib — sculpture microperforate and microreticulate; and Ic — sculpture macroreticulate. Type II (4-colporate) is represented by only one subtype IIa — sculpture psilate, rough, and foveolate. The revealed characteristics of pollen grains are taxonomically significant at the generic and specific levels. Our palynomorphological data are consistent with the results of molecular phylogenetic studies. Pollen grains in Teedieae are typically characterized by the colporate aperture type (probably ancestral in Scrophulariaceae) and rather primitive characters of surface and sculpture of colpi membranes. Similar palynomorphological patterns in Teedieae and Buddlejeae can be viewed as ancestral for pollen characters observed in more advanced clades of Scrophulariaceae.

Can Triticum urartu (Poaceae) be identified by pollen analysis? Implications for detecting the ancestor of the extinct two-grained einkorn-like wheat.

The domestication of the one-grained einkorn (Triticum monococcum) in the Near East is relatively well known. However, an independent two-grained einkorn-like domestication has been archaeobotanically detected and scarce information is available. Triticum urartu, a wild wheat, was not fully described until the 1970s because the phenology does not allow it to be distinguished easily from wild einkorn (Triticum boeoticum subsp. thaoudar), although a genetic separation exists. Both species are mostly two grained and could potentially be the relatives of the extinct two-grained form. Pollen grains of several genetically well-identified wheat species, including T. urartu and T. boeoticum subsp. thaoudar, were studied by measuring the grain diameter and examining the exine sculpturing with phase-contrast microscopy and scanning electron microscopy to gain an insight into differences enabling taxonomic identification. This work showed that, although T. urartu pollen is smaller on average, grain diameter is not sufficient because of the size overlap between the species, but T. urartu presents a different exine sculpturing (scabrate) from other Triticum spp. (aerolate). This outcome is useful for taxonomists and archaeobotanists. First, it will allow a simple re-classification of herbarium materials. Second, further research could establish whether T. urartu was cultivated. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 177, 278–289.

Pollen phenotyping and performance in rocoto chili (Capsicum pubescens Ruiz et Pav., Solanaceae)

The rocoto chili (Capsicum pubescens) is a species native to the highlands of South America, which is cultivated for its fruits. The species is regarded as self-compatible; however, self-incompatible strains and even a variable degree of self-incompatibility have been found. To characterise pollen grains and determine whether there is also variation in pollen performance and male fertility in the species, pollen morphology, cellular state, starch content, viability, longevity and germinability were analysed in plants obtained from the germplasm cultivated in Argentina. All the individuals studied were male fertile, showing a high percentage of vital pollen, capable of germinating in vitro. Some pollen features were uniform (e.g. exine sculpture, number of nuclei at maturity), but there were significant variations in pollen performance among the plants studied.

Pollen morphology of the genus Alchemilla L. (Rosaceae) in Iran

This paper reports the morphological characters of 18 Iranian species of the genus Alchemilla using light and scanning electron microscopy. The pollen grains are monad, radially symmetrical, isopolar, or subisopolar; small to medium in size; tri- and tetracolporate; rectangular to cylindrical (from equatorial view) and triangular to circular (from polar view) in outline; and prolate-spheroidal to subprolate and prolate in shape. The exine ornamentation is psilate and microechinate. Based on the exine sculpturing and microechinate distribution pattern, three main types, four subtypes, and two categories of pollen grains were recognized. We used cluster analysis and principal component analysis to determine the potential contribution of pollen morphological characters to the species relationships. Our findings revealed the significance of palynological evidence in explaining the species relationship. The results of two multivariate analyses showed a close affinity among the seven studied species (A.amardica, A. sericata, A. fluminea, A. kurdica, A. hyrcana, A. sedelmeyeriana, and A. pesudocartalinica).

Pollen morphology of the tribe Phyllodoceae (Ericoideae, Ericaceae) and its taxonomic significance

Pollen morphology of 13 taxa belonging to 5 genera of the tribe Phyllodoceae (Ericaceae) was examined by means of light and scanning electron microscopy (LM and SEM, respectively), or SEM alone. In Phyllodoceae, 3-colpor(oid)ate, minute to medium, oblate pollen grains are united usually in tetrahedral tetrads. Pollen tetrads are generally characterized by the presence of viscin threads except Elliottia pyroliflora, Epigaea asiatica and Phyllodoce caerulea. The absence of viscin threads might indicate to a secondary loss, since these are present at least in some species within all the genera of Phyllodoceae. The pollen morphological data confirm the infra- and inter-generic relationships as identified by molecular phylogeny of Phyllodoceae and/or vice-versa. Although various palynological characters were found to be taxonomically important at different taxonomic levels, the apocolpial exine sculpture is emerged as one of the most important palynological features of systematic importance. The rugulate apocolpial exine with striate secondary sculpture and a reduced colpus might be apomorphic palynological character states for this tribe and Ericaceae as well. Hitherto, it is the first SEM study of Rhodothamnus pollen.DOI: http://dx.doi.org/10.3329/bjpt.v21i2.21351Bangladesh J. Plant Taxon. 21(2): 129-137, 2014 (December)

Pollen morphology of Erica L. and related genera and its taxonomic significance

Pollen morphology of a total of 25 species of Erica (23 species) and its closely related genera Calluna (monotypic) and Daboecia (monotypic) was examined by means of light and scanning electron microscopy (SEM), or SEM alone. The pollen tetrads of E. multiflora and E. trimera ssp. keniensis, and monads of E. barbigeroides and E. recurvifolia, were examined with transmission electron microscopy to study the exine stratification. The quantitative features of Erica pollen have varied widely. However, the exine sculpture of Erica pollen is often characterised by the presence of numerous minute granules as secondary sculpture. Calluna pollen is characterised by irregular tetrads and perforated septum, and the Daboecia pollen tetrads by larger values of the D/d, P/E and 2f/D ratios. The P/E ratio and exine architecture showed distinct differences between Erica monads and tetrads. Among the Erica species having pollen tetrads, two distinctly different palynomorphological groups could be identified based on the 2f/D ratio. Two distinct groups could also be differentiated on the basis of the L/P ratio within the Erica species producing monads. Palynological characters, therefore, might be featured as a useful tool to clarify infrageneric classification system for the large genus Erica.

Lilium spp. pollen in China (Liliaceae): Taxonomic and Phylogenetic Implications and Pollen Evolution Related to Environmental Conditions

Recent molecular and karyologic studies have significantly modified delimitation of Lilium. However, despite the importance of pollen evolution in the genus comprehensive studies with electron microscopy and evaluation of pollen evolution are lacking. Therefore, we studied pollen morphology in a sample of 65 individuals from 37 taxa covering all the sections distributed in the world, using scanning electron microscopy. Our collection of 49 individuals from 21 taxa covering all five sections in China was also included in the database. We found pollen tetrads in L. bakerianum. Based on present and previous studies, our results suggest that pollen from L. formosanum should be classified as a new type, Formosanum. Combined with morphological and molecular evidence, pollen sculpture patterns appear to reflect phylogenetic relationships and are useful for species or subsection delimitation. Based on a comprehensive survey and correlation with potential functional implications, we propose the following hypothesis: evolution of an exine sculpture shows pollen type trends from Martagon → Callose → Concolor → Formosanum. The evolutionary trend regarding pollen sculpture and size could be related to selective pressure to adapt to environmental conditions. Pollen size and shape showed a significantly positive correlation with annual precipitation, and smaller pollen grains appear to adapt better in habitats with extreme conditions. Evolution trends in exine sculpture do not appear to be definitively correlated with pollen size and shape.