Among monocots, compound pollen grains are known in Alismatales (Araceae, Hydrocharitaceae, Scheuchzeriaceae), Poales (Bromeliaceae, Cyperaceae, Juncaceae, Typhaceae, Thurniaceae), Asparagales (Amaryllidaceae, Orchidaceae), Commelinales (Philydraceae) and Pandalales (Velloziaceae) (Knox & McConchie, 1986; Copenhaver, 2005). Pollen is globular and free but in the marine genera (Thalassia and Halophila) - the pollen grains are carried in chains, like strings of beads. Small effective pollen loads suggest that pollen competition intensity is low. Spore morphology is diverse and complex in ferns, thus serving as an important indicator of taxonomy. Each record may contain multiple individual grains and images. The anther first appears as a cylindrical structure composed of a mass of meristematic cells, which consists of three “germ’ layers designated as L1, L2 and L3, which gives rise to different anther tissues. Publication of " A Field Guide to Aquatic Plants of Myanmar", National Museum of Nature and Science and Forest Research Institute of Myanmar (Ministry of Natural Resources and Environmental Conservation) started a new joint research project from 2016 towards, Explore the evolutionary process of the Aristolochia kaempferi group (Aristolochiaceae), Illiciaceae and Schisandraceae, together with other members of Austrobaileyales have been identified as one of the earliest diverging lineages of angiosperms, within the ANITA grade. Flowering in Thalassia is coincident with the spring tides and the pollen is released as a mass suspended in a thecal slime which contains approximately 5 per cent by weight carbohydrate, the principal mono-saccharide being mannose. The central cytoplasmic part is the source of nuclei responsible for fertilization. (1997). pages=167-170. Approximately 250 pollen samples from tribe Cercideae were studied using light as well as scanning and transmission electron microscopy, with 58 of those samples taken from 55 species of 12 genera matching those analysed in a recent molecular phylogeny. An examination of seasonal environments in the tropics at present and the fossil record of deciduous and wind pollinated angiosperms supports this contention. Further development of male gametophyte occurs on stigma after pollination .The smaller ... Hypohydrophily (below the surface of water eg. Cite this article: SUN Kun,CHEN Jia-Kuan,ZHANG Zhi-Yun. Publication and Copyright Transfer Agreement, (School of Life Sciences, University of Science and Technology of China,Hefei 230027). Anatomical structures of the achenes suggested relationships with greatest concordance to those in the molecular phylogeny. Air bubbles cause the male flower to surface. or microverrucate exines represented primitive states for tribe Sanguisorbeae. Aperture Number- An aperture refers to the thinner regions within a pollen grain. Next Articles, SHEN Xian-Sheng　ZHANG Wen-Rui　YANG Jie-Pin. 2 Pollen grain of Egeria densa. The evolution of pollen morphology in the two families, together with other members of Austrobaileyales, is discussed in comparison with the molecular phylogenies. However, this assumption has rarely been tested using empirical data. The intine consists, at least in part, of cellulose or hemicellulose. Ann. Precocious division of the microspore nucleus in Thalassodendron launches the binucleate pollen phase soon after the spores separate from the tetrad. We tested the statistical significance of an association between pollen ornamentation and pollination system in two families of the monocotyledons, the Araceae and the Arecaceae, taking into account the phylogenetic framework. Sexual and natural selection on pollen morphology in Taraxacum, A comparative analysis of pollinator type and pollen ornamentation in the araceae and the arecaceae, two unrelated families of the monocots, Reproductive ecology and postpollination development in the hydrophilous monocot Ruppia maritima: Reproductive ecology and postpollination development in Ruppia, Ingenious floral structure drives explosive pollination in Hydrilla verticillata (Hydrocharitaceae), A molecular phylogeny, morphology and classification of genera of Ranunculeae (Ranunculaceae), Molecular phylogenetic and morphological study of Kohautia (Spermacoceae, Rubiaceae), with the recognition of the new genus Cordylostigma, Ancestral state reconstruction reveals the diversity and evolution of spore ornamentation in Adiantum (Pteridaceae), Further Interpretation of Wodehouseia spinata Stanley from the Late Maastrichtian of the Far East (China), Evolutionary constraints on disparity of ericaceous pollen grains, Exine and Aperture Patterns on the Pollen Surface: Their Formation and Roles in Plant Reproduction, Pollen Morphology in North American Species of Trillium, Reproduction in Seagrasses: Pollen Development in Thalassia hemprichii, Halophila stipulacea and Thalassodendron ciliatum, The significance of pollen morphology in the Apocynaceae, Pollination mechanisms in the Hydrocharitaceae, Comparative external pollen ultrastructure of the Araceae and putatively related taxa, Reproduction in Seagrasses: Nature of the Pollen and Receptive Surface of the Stigma in the Hydrocharitaceae, The Evolutionary Significance of the Exine, Wind Pollination in the Angiosperms: Evolutionary and Environmental Considerations. The pollen grains were prepared for Light Microscopy (LM) according to Erdtman (1952). Annals of the Tsukuba Botanical Garden, 22, 11 –13. Recommend, Add to citation manager EndNote|Ris|BibTeX, URL: Species of Kohautia can easily be distinguished from other Spermacoceae by their monomorphic short‐styled flowers in which anthers and stigma are included in the corolla tube, with the stigma always positioned below the anthers. These data, together with palynological data for taxa previously studied, were mapped into recent molecular phylogenetic trees to re-evaluate the existing classification and phylogenetic relationships in the two families. In Thalassodendron and Halophila the periplasmodial residue forms a superficial coating on the pollen wall and tetrad tube. This overview of pollen structure presents a summary of the distribution of pollen morphological variation, providing data which allows the structural variation in pollen to be compared and contrasted in evolutionary and taxonomic contexts. The pollen grains are usually inaperturate, spheroidal to subellipsoidal in shape, but those of Stratiotes aloides and Halophila ovalis are monosulcate. The hypohydrophilous genera Thalassia and Najas are characterized by pollen grains … Flora - Morphology Distribution Functional Ecology of Plants. Chinese Bulletin of Botany ›› 2002, Vol. Hydrocharitaceae . Gard. Both methods revealed several well–supported, small terminal clades which correspond to previously described genera, characterised by unique morphological features and character combinations. Pollen grains of 57 species (representing 42 genera) of the Chloridoideae have been investigated using light, scanning and transmission electron microscopy. Pollen morphology of 15 species in nine genera of Hydrocharitaceae was examined with light microscope (LM), scanning electron microscope (SEM) and transmission electron microscope (TEM). The inaperturate pollen grains ofOttelia are characterized by the spinous protrusions and the granular foot … Among the different types of relationship implying pollen ornamentation that have been suggested, the existence of a link between exine sculpturing and pollinator type has often been proposed and was even evidenced in certain situations (see additional file 1). Here, we review the current state of knowledge about the exine and aperture patterns, their perceived roles in plant reproduction, and the cellular and molecular mechanisms that guide their formation. Publisher=Nippon Chigakukenkyu-Kai Halophila disperses strings of four reniform trinucleate pollen grains contained in a mucilaginous moniliform tube. The process of transfer of pollen grains from another to stigematic surface of the. Kohautia Cham. Geographic isolation and adaptions may have triggered the evolution of morphological characters. The wall of the pollen grain is very thin , and splits easily after drying. Premise: except for the microechinate-verrucate pattern and subprolate to spheroidal shapes observed in Hagenia. Annals of the Tsukuba Botanical Garden, 22, 11 –13. The recovered evidence fits well with the expectations of limitations on available pollen morphological disparity, and suggests that innovation of pollen germination traits may have little effect on species diversification. and Cordylostigma. Our resulting neighbor-joining distance tree provides the following insights: (1) none of the previous classification systems phylogeny. These arise by successive transverse partitioning of an elongate mother cell and the linear unit so formed is maintained throughout pollen development. Annals of the Tsukuba Botanical Garden 19:7-12. Epihydrophily is pollina- tion at the water surface (Cox, 1988; Philbrick, 1988, 1991), e.g., Vallisneria (Hydrocharitaceae). Sixteen genera (4.2%) have no obvious terrestrial relatives but belong to exclusively anemophilous families; the anemophily, however, could be associated with life in water. Access scientific knowledge from anywhere. In a 3-D pollen morphospace, most major clades appear to occupy distinct neighbouring regions, whereas the subfamily Epacridoideae overlaps extensively with other subfamilies. Le pollen cru également appelé « pollen frais » ou est congelé immédiatement après la récolte et conservé en tant que tel. Pollen grains, the male gametophytes of seed plants, surround themselves with a complex pollen wall for protection from various environmental stresses. An exine layer is not found in Halophila stipulacea where reniform pollen grains are contained within transparent moniliform tubes. It is commonly stated that smooth pollen grains are associated with wind or water nation. 5 Exine structure of E. densa with spine, fine granules (fg), rough granules (rg) and basal layer (bl). Subsequent development of the surviving, functional microspores does not differ essentially from the pattern of morphogenesis in terrestrial flowering plants. We analyzed the stamen movements during pollen dispersal process and conducted several controlled experiments to study the process of storage and release of elastic potential energy in explosive pollination. The pollen grains are usually inaperturate, spheroidal to subellipsoidal in shape, but those of Stratiotes aloides and Halophila ovalis are monosulcate. The verrucate protrusions develop into spines during free microspore stage. Palynological data on Illiciaceae and Schisandraceae confirm phylogenetic relationships within these... Pollen morphology and its phylogenetic significance in tribe Sanguisorbeae (Rosaceae), Evolution and diversity of pollen morphology in tribe Cercideae (Leguminosae), Phylogeny of the family Hydrocharitaceae inferred from rbcL and matK gene sequence data, Phylogeny of Najas (Hydrocharitaceae) revisited: Implications for systematics and evolution. Hydrocharitaceae is a plant family that includes a number of species of aquatic plant, ... the inner ones sometimes sterile. Surveys of corbiculae (pollen basket) contents from foraging bumblebees and feces of flies showed that pollen grains consumed by both kinds of visitors are similar in spine characteristics and size to those produced by the donor. Caulinia. Discovery of male plants of Najas marina L. (Hydrocharitaceae) in Britain R. J. HANDLEY* and A. J. DAVY School of Biological Sciences, University of East Anglia, Norwich, NR4 7TJ ABSTRACT The dioecious, annual macrophyte Najas marina is represented in Britain only in the Norfolk Broads. & Schltdl. The deposition and assembly of exine, the outer layer of the pollen wall, lead to the formation of patterns on the pollen surface that are species specific, tremendously diverse, and often very beautiful. Conclusion: In this study, we show that the relationships between the ornamentation type and the pollination system depend on the family and hence vary among taxonomic groups. 1 Polyad : 14 Tetrad- A group of four united pollen grains. The ancestral flowers of Araceae were pollinated by beetles while ancestral pollination in Arecaceae is equivocal. We suggest that spore ornamentation evolved from simple to complex in Adiantum. Scanning electron microscopy (SEM). Phylogeny of the family Hydrocharitaceae inferred from rbcL and matK gene sequence data. Pollen germinated within 15 min after pollination. Journal of Plant Research, 110, 329 –337. In nature only the grains in contact with the stigma develop pollen tubes so one rarely sees more than 3 grains in a tetrad germinating. Fig. This is particularly true in the case of the many different kinds of marine angiosperms included in the Hydrocharitaceae. Background and aims: The characteristic form of the pollen in this genus is attained during post-meiotic growth and differentiation, as in other genera belonging to the same family. These patterns arise due to exine's assembly into various nano‐ and microstructures, and due to the absence of exine deposition at certain areas of the pollen surface. In Thalassia the tapetal periplasmodium is progressively transformed into thecal slime. Adventitive polyembryony occurs in. We postulated that relative to sexual congeners, apomictic dandelions undergo relaxed selection on traits associated with male mating success. Because of the great diversity of morphological features and lack of molecular phylogeny for the tribe, the classification of its genera has always been controversial. In conjunction, morphological traits and phylogeny are used to study taxonomy and recent character evolution. • 研究简报 • The basic and most common type is tricolpate, which is observed in most of the Ranunculus species. SEM. The tetrad tube substance originates in the tapetal periplasmodium and deposition begins soon after meiosis. Flies picked up larger pollen from flowers than expected at random. In explosive pollination, many structures and mechanisms have evolved to achieve high‐speed stamen movement. Join ResearchGate to find the people and research you need to help your work. The similarity in enzymatic properites of the pollen wall and stigma pellicle suggests that, intriguingly, a similar mechanism of cuticle erosion might well follow compatible pollination both on land and in the sea. Alismataceae are sister groups of Hydrocharitaceae; (4) the three marine genera,Halophila, Enhalus andThalassia, are monophyletic; and (5) a peculiar pollination mechanism specific to Hydrocharitaceae (Hydrocharitaceae-epihydrophily), Table 1: Aquatic plant species collected from Saudi Arabia for pollen morphological studies: The pollen grains were mounted in unstained glycerin jelly and observations were made with a Nikon Type-2 microscope, under E40, 0.65 and oil immersion (E100, 1.25), using a 10x eyepiece. Pollen reception, pollen germination, pollen tube growth, and carpel morphology were characterized. Premise: Given that grains with spine distance phenotypes resembling those of T. ceratophorum better adhere to the bee, we hypothesize that the reduced spine characteristics of T. officinale may inhibit introgression in mixed populations. Methods: These regions will differ in color from the rest of the grain. In addition to these diploid sporophytic tissues, the anther also contains haploid microspores that fill the pollen sacs and differentiate into pollen grains. The pollen grains ofOttelia alismoides are inaperturate, not omniaperturate, because of the well-developed foot layer. Tanaka, N. 2000. Pollen morphology of 15 species in nine genera of Hydrocharitaceae was examined with light microscope (LM), scanning electron microscope (SEM) and transmission electron microscope (TEM). The anemophilous genus Limnobium has reticulate pollen grains. 4 Pollen grain of Blyxa japonica with spines. These conditions do not exist in northern temperate forests, or in prairies, or in savannas. It is a highly varied and complex group which has undergone many taxonomic re-organisations, and is currently the subject of further systematic studies. Tanaka, N., Setoguchi, H. and Murata, J. KEAM 2004. Hygroscopic weight gain of pollen grains from Juniperus species Landon D. Bunderson & Estelle Levetin Received: 12 June 2013/Revised: 26 June 2014/Accepted: 27 June 2014/Published online: 10 July 2014 # ISB 2014 Abstract Juniperus pollen is highly allergenic and is pro-duced in large quantities across Texas, Oklahoma, and New Mexico. Family in the Global Pollen Project's Master Reference Collection. In both these families, pollen apertures and exine, Pollen grains of tribe Sanguisorbeae (Rosaceae, Rosoideae) were examined using scanning electron microscopy to identify useful The other parts constituting the wall of the grain are an inner layer, the intine, and an outer layer, the exine.     This paper describes the characteristics of the pollen and the receptive surfaces of the stigmas in the three marine angiosperms included in the Hydrocharitaceae. out a phylogenetic, Najas (Hydrocharitaceae) is a cosmopolitan genus of 30–40 species of aquatic plants. Cytochemical tests show that the pollen wall in the three species contains acidic and neutral polysaccharides and acid hydrolase acitivity is detected in the intine of H. stipulacea and T. hemprichii. All rights reserved. in shape, had operculate or pontoperculate apertures, and had three apertures, except for Margyricarpus (tetraperturate). Definition. 2. This study analyzes the evolution of spore ornamentation in once-pinnate maidenhair ferns (Adiantum) using scanning electron microscopy and ancestral state reconstruction. Pollination of the genus Hydrilla (Hydrocharitaceae) by waterborne pollen grains: 2. The previously inferred tropical Asian origin of the genus is rejected and, instead, North America is discerned as the ancestral area, implicating dispersal of the most recent common ancestor of Najas and its sister genera in Hydrocharitaceae from tropical Asia. The general features of pollen morphogenesis in three marine monocotyledons, Thalassia hemprichii, Halophila stipulacea and Thalassodendron ciliatum, are described in this paper. Two pollen types are previously not recorded in Gramineae. Bar = 10 mm. A foot layer is formed by accumulation of lamellated structure. Pollination of the genus Hydrilla (Hydrocharitaceae) by waterborne pollen grains: II. Ruppia maritima exhibits incomplete protogyny, allowing for delayed selfing. Distribution Recent Palaeo Naiad Family. Two aperture patterns and nine exine patterns are distinguished using SEM and TEM. (including Batrachium, Aphanostemma and Gampsoceras) reflects best the molecular phylogeny and morphological diversity of the tribe. The specialized Illiciaceae and Schisandraceae comprise a clade defined by apomorphic characters including pollen grains with three or six colpate apertures. Pollen is an airborne allergen, which is picked up and carried by the wind. or flies (Diptera: Syrphidae and Muscoidea) and assessed natural selection by testing whether pollen traits defend against consumption. An exine layer is not found in Halophila stipulacea where reniform pollen grains are contained within transparent moniliform tubes. Experimental pollinations using both putatively outcross and self pollen were conducted in the greenhouse and inflorescences were collected at appropriate intervals after pollination. -Pollen morphology may be correlated with pollination vectors (Hesse, 2000), in particular aperture and exine ornamentation characteristics are correlated with specific pollinators (Proctor & al., 1996; To document diversity of aquatic plants in Myanmar. 3. Studies of the aerodynamics of particle transport and capture suggest that the conditions most propitious for effective wind pollination are as follows: (1) production and release of large numbers of grains; (2) both anthers and stigma exposed; (3) grains falling within a certain size range (20-40μ); very small grains will be dispersed readily but cannot be captured efficiently by the stigma, large grains have a high terminal velocity, hence will settle too rapidly; (4) exine of grains thin (or with large air spaces), sculpture smooth; (5) the stigma should present much surface area to capture grains, but, since collection efficiency will decrease with increasing stigma diameter, the increase in surface should be accomplished through the evolution of a complex stigma with many branches of small diameter; (6) individuals of the species should not be too widely spaced in the vegetation; (7) the vegetation should be open in structure or deciduous; thus there will be few obstructions to transport during at least one portion of the year; (8) flowering must be closely coordinated by relatively unambiguous environmental stimuli; (9) pollen release (hence flowering) should coincide with the most favorable time of the year for transport (low probability of precipitation, adequate winds and turbulence, deciduous season). The pollen was probably produced by wetland or aquatic plants, adapted to a sudden change in the water regime during the vegetation season. Acid phosphatase activity is localized beneath the cuticle at the tips of the stigma papillae. Stems short or elongated, sometimes stoloniferous. Chinese Bulletin of Botany, 2002, 19(04): 484-487. Molecular data (atpB‐rbcL, petD, rps16, trnL‐trnF, ETS, ITS) confirm that the genus is biphyletic. Cytochemical tests show that the pollen wall in the three species contains acidic and neutral polysaccharides and acid hydrolase acitivity is detected in the intine of H. stipulacea and T. hemprichii. Earlier analyses identified tropical Asia, which harbors more than one-third of all species, as the area of origin for the genus, but this inference. Aperture number, aperture structure, pollen shape, and exine sculpturing were variable within Sanguisorbeae and Reference Details: Electrophoretic analysis of the pollen-free slime shows a single glycoprotein component. the Flora of Myanmar by conducting the field expeditions to unexplored areas in Myanmar such as Tanintharyi (Tenasserim) to make the checklist of the flowering plants, bryophytes, lichens, fungi etc. Tsukuba Bot. Halophila stipulacea (Hydrocharitaceae) in the Aegean Sea (Turkey) Berrin Dural1*, Emine ükran Okudan2, Nilsun Demir3, ... pollen grains extend from the hypanthium, which functions as a style, into the ovary, where fertilisation takes place. The ancestral ornamentation in Araceae is foveolate/reticulate. The male flower of a submerged plant Hydrilla verticillata is reported to be able to release pollen explosively after leaving from the mother plant for a period of time, but the mechanism of stamen movement and the related functional structure in this species are unclear. Floral, pollen and seed characters were studied to morphologically characterize Kohautia s.str. in Shaffer-Fehre's (1991) system based on seed coat structures, is an ingroup of Hydrocharitaceae; (3) Limnocharitaceae and Pollination of the genus Hydrilla (Hydrocharitaceae) by waterborne pollen grains. Thalassodendron disperses filiform trinucleate pollen grains. Sexual selection may act on exine traits that facilitate male mating success by influencing the transfer of pollen from the anther to the body of the pollinator, while natural selection acts to increase pollen survival. Outgroup comparison indicated that operculate colpi, three apertures, and polymorphism for striate The purpose of this study was to characterize reproductive ecology and postpollination development in water-pollinated Ruppia maritima L. No evidence for correlations was found between dimension of pollen disparity and species diversity at either the subfamily or generic level. Phylogeny of the family Hydrocharitaceae … Water-pollination (hydrophily) is a rare but important pollination mechanism that has allowed angiosperms to colonize marine and aquatic habitats.