Water-pollination (hydrophily) is a rare but important pollination mechanism that has allowed angiosperms to colonize marine and aquatic habitats. 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). Pollination of the genus Hydrilla (Hydrocharitaceae) by waterborne pollen grains: 2. flower the help of water is called: (A) anemophily (B) zoophily (C Axelrod has suggested that the deciduous habit evolved in response to seasonal drought as angiosperms migrated into lower middle latitudes during the early Cretaceous. Authors=TSUJI Sei'ichiro. The intact pollen grains can not be preserved in natural conditions. 0 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. The ancestral ornamentation in Araceae is foveolate/reticulate. Catapult‐like stamens, spoon‐shaped sepals and enclosed united bracts in the spathe together constitute the functional structure in rapid stamen movement of H. verticillata. number=4/6. Access scientific knowledge from anywhere. Pollen characters are most useful at the generic level and, when mapped on to a molecular phylogenetic tree of the tribe, A correlation between ornamentation type and pollination was highlighted in Araceae although the results slightly differ depending on the method and the options chosen for performing the analyses. Aquatic angiosperms have evolved from terrestrial ancestors several times. Flora - Morphology Distribution Functional Ecology of Plants. except for the microechinate-verrucate pattern and subprolate to spheroidal shapes observed in Hagenia. Chinese Bulletin of Botany, 2002, 19(04): 484-487. 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. It is possible that the evolution of wind pollination in the angiosperms paralleled the evolution of the deciduous habit. We also show that the method chosen may strongly influence the results. The environment of the tropical rain forest is unsuitable for anemophily: (1) species diversity is very high, hence individuals of the same species are apt to be widely spaced; (2) the forest is densely structured, hence wind velocities are low and there are many obstacles to transport; (3) there is no leafless season; (4) rainfall is frequent throughout the year, hence transport will be limited; (5) there are few unambiguous stimuli which can coordinate flowering; (6) potential animal pollinators are abundant. Floral, pollen and seed characters were studied to morphologically characterize Kohautia s.str. Here we applied a molecular phylogenetic approach using balanced taxon sampling (1) to test infrageneric classifications, (2) to re-assess biogeographic origin, and (3) to explore whether and how polyploidy characterizes evolutionary lineages. The pollen grains ofOttelia alismoides are inaperturate, not omniaperturate, because of the well-developed foot layer. Bar = 10 mm. Scanning electron microscopy (SEM). are concordant with a monophyletic Agrimoniinae and a clade comprising Margyricarpus+Acaena+Polylepis+Cliffortia+Sanguisorba in the Sanguisorbinae. Mainly because of this unique floral morphology, Kohautia was considered to be a distinct genus. Blyxa kasaragodensis, a new species of Hydrocharitaceae from the ponds in the laterite plateau of Malabar coast, Kerala, India. We currently have 1 digitised slides. Gard. Furthermore, the distribution of species in present pollen morphospace showed a strong central tendency, with the core compartment containing a large number of species from species-rich genera. 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. & Schltdl. Thalassia disperses spherical trinucleate pollen grains. or microverrucate exines represented primitive states for tribe Sanguisorbeae. Herbs, annual or perennial, submerged or floating, aquatic, in fresh or brackish water or marine. The hypohydrophilous genera Thalassia and Najas are characterized by pollen grains … The anemophilous genus Limnobium has reticulate pollen grains. The pollen grains of the Hydrocharitaceae are spherical, inaperturate, and form monads or tetrads, while those of the Najadaceae are elliptical, inaperturate, and form monads. 5 Exine structure of E. densa with spine, fine granules (fg), rough granules (rg) and basal layer (bl). Recommend, Add to citation manager EndNote|Ris|BibTeX, URL: Premise: 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. The stigmas of the three seagrasses are papillate and of the ‘dry’ type possessing a continuous protein-aceous pellicle subtended by a cuticle. Among these wind-pollinated aquatics, 100 genera have obvious terrestrial relatives that are also wind pollinated. Bar = 10 mm. To gather more basic information regarding the adaptive evolution of Hydrocharitaceae, we have carried The infratectum structure suggests that Wodehouseia should be placed within an advanced group of eudicots. Pachystigma because of the existence of Pachystigma Hochst. Definition. 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. Anatomical structures of the achenes suggested relationships with greatest concordance to those in the molecular phylogeny. The wall of the pollen grain is very thin , and splits easily after drying. Key results: Tanaka, N., Setoguchi, H. and Murata, J. Tanaka, N. 2000. An exine layer is not found in Halophila stipulacea where reniform pollen grains are contained within transparent moniliform tubes. Air bubbles cause the male flower to surface. Tanaka, N. 2003. Aperture Number- An aperture refers to the thinner regions within a pollen grain. Morphological Observation of the Pollen Grains of Hydrilla verticillata[J]. requires re-evaluation using worldwide taxon sampling. 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. Geographic isolation and adaptions may have triggered the evolution of morphological characters. Methods: The pollen of the Cercideae has long been known to be diverse and varied, but problematic species and generic, The family Hydrocharitaceae, with 15 genera and ca. Furthermore, if other plant species that evolve away from obligate entomophily also exhibit less effective pollen dispersal traits (sensu. Further development of male gametophyte occurs on stigma after pollination .The smaller ... Hypohydrophily (below the surface of water eg. Air bubbles cause the male flower to surface. A similar type of floral organisation thus seems to have evolved twice independently, resulting in similar, but distantly related lineages. Hydrocharitaceae. In Thalassia the tapetal periplasmodium is progressively transformed into thecal slime. delimitations have previously hindered our understanding of the similarities, differences, evolution and taxonomic significance of the various pollen structures found within the tribe. The pollen grains are usually inaperturate, spheroidal to subellipsoidal in shape, but those of Stratiotes aloides and Halophila ovalis are monosulcate. Premise: The entomophilous genera Egeria, Blyxa, Ottelia, Stratiotes, and Hydrocharis share pollen grains that have projections like spines or bacula. It is a highly varied and complex group which has undergone many taxonomic re-organisations, and is currently the subject of further systematic studies. Two aperture patterns and nine exine patterns are distinguished using SEM and TEM. The mean adjusted pollen tube growth rate was 551 μm/h. 4 Pollen grain of Blyxa japonica with spines. 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). Publisher=Nippon Chigakukenkyu-Kai However, little is known about reproductive development in the life history stage between pollination and fertilization (the progamic phase) in hydrophilous plants. 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. In Thalassodendron and Halophila the periplasmodial residue forms a superficial coating on the pollen wall and tetrad tube. 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. Polyploidy has been widely observed in the genus but its correlation with phylogeny has yet to be explored. Outgroup comparison indicated that operculate colpi, three apertures, and polymorphism for striate The pollen morphology of 11 genera and 11 species of the Hydrocharitaceae and one species of the Najadaceae was studied using scanning and transmission electron microscopies, and the exine structures and sculptures are discussed in relation to pollination mechanisms and the molecular phylogeny. The entomophilous genera Egeria, Blyxa, Ottelia, Stratiotes, and Hydrocharis share pollen grains that have projections like spines or bacula. (V–VI) were found only in subtribe Agrimoniinae. In order to study the biological feature of a submerged plant, we observed the form and structure of the pollen grain of Hydrilla verticillata of Hydrocharitaceae by optical microscopy and SEM. delineate six pollen types. Pollination of the genus Hydrilla (Hydrocharitaceae) by waterborne pollen grains. The stigma pellicle exhibits cytochemically detectable esterase activity and binds the lectin concanavalin A. in Shaffer-Fehre's (1991) system based on seed coat structures, is an ingroup of Hydrocharitaceae; (3) Limnocharitaceae and 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 … ... A relationship between abiotic pollination (wind and water) and smooth (or nearly) pollen grains has been proposed in many studies [1,22] but concerning biotic pollination, the results are more controversial. While an infrageneric subdivision into two subgenera is generally accepted, various sectional classifications proposed in subg. POLLEN IN HYDROPHILOUS ANGIOSPERMS 381 Halophila decipiens The pollen grains are filiform with a massive stratified intine covered by a thin unstructured and unornamented exine. The entomophilous genera Egeria, Blyxa, Ottelia, Stratiotes, and Hydrocharis share pollen grains that have projections like spines or bacula. Flies picked up larger pollen from flowers than expected at random. 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 ancestral flowers of Araceae were pollinated by beetles while ancestral pollination in Arecaceae is equivocal. Acid phosphatase activity is localized beneath the cuticle at the tips of the stigma papillae. Halophila disperses strings of four reniform trinucleate pollen grains contained in a mucilaginous moniliform tube. In Hydrilla (Hydrocharitaceae) the pollen grains are heavy and are propelled through air from the male to the female; although this mechanism almost certainly evolved in water, it is not considered to be true anemophily where buoyant grains are carried by air movements. (1997). Publish_year=1975. Abstract: In order to study the biological feature of a submerged plant, we observed the form and structure of the pollen grain of Hydrilla verticillata of Hydrocharitaceae by optical microscopy and SEM. The anemophilous genus Limnobium has reticulate pollen grains. Hydrocharitaceae is a flowering plant family including 16 known genera with a total of ca 135 known species (Christenhusz & Byng 2016 ), that including a number of species of aquatic plant, for instance the tape-grasses, the well known Canadian waterweed and frogbit Hydrocharis morsus-ranae. No correlation was found in palms. 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. An examination of seasonal environments in the tropics at present and the fossil record of deciduous and wind pollinated angiosperms supports this contention. Pollen is globular and free but in the marine genera (Thalassia and Halophila) - the pollen grains are carried in chains, like strings of beads. Although the intricate patterns of exine and apertures have been drawing attention for centuries, it is still not clear how exactly they develop, what genes are involved in their formation, and what purpose they serve. Two distantly related clades correspond to the subgenera Kohautia and Pachystigma Bremek. After the male flower is liberated from the mother plant, the stamens unfold rapidly with the sepals under adhesion and transfer the elastic potential energy to the filament in seconds. sculpture were found to be very informative when considered in the context of recent understanding of evolutionary patterns. Exine structure and its developmental program in a submerged plant,Ottella alismoides (L.) Per. They ensure that the pollen can be released on the water surface, and thus adapt successfully to the pollen‐epihydrophilous pollination. 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. pollen to attach to hairs of flower-visiting bumblebees (Bombus spp.) These regions will differ in color from the rest of the grain. Most pollen grains consist of three distinct parts. Home; Master Reference Collection ; Hydrocharitaceae; Digitised Reference Slides. Journal/Book_names=Chigakukenkyu.     Each record may contain multiple individual grains and images. Publish_Country=Japan. All rights reserved. were supported by molecular phylogenetic tree; (2) Najas (Najadaceae), which has never been included in Hydrocharitaceae except Annals of the Tsukuba Botanical Garden, 22, 11 –13. The family includes both fresh water and marine aquatics. Pollination of the genus Hydrilla (Hydrocharitaceae) by waterborne pollen grains. Bar = 1 mm. We postulated that relative to sexual congeners, apomictic dandelions undergo relaxed selection on traits associated with male mating success. The pollen grains were prepared for Light Microscopy (LM) according to Erdtman (1952). Pollination of the genus Hydrilla (Hydrocharitaceae) by waterborne pollen grains: II. Family in the Global Pollen Project's Master Reference Collection. The pattern of the exine sculpture and sporoderm ultrastructure suggests that insects contributed to pollination. Visual effect ( Diptera: Syrphidae and Muscoidea ) and assessed natural selection testing. 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Thalassodendron and Halophila ovalis are monosulcate visual effect implicated in attachment and recognition of the pollen grains are within. Usually inaperturate, not omniaperturate, because of the family includes both fresh water and aquatics... Products could be implicated in attachment and recognition of the well-developed foot layer not... Binucleate pollen phase soon after the spores separate from the rest of the pollen-free slime a. Those in the spathe together constitute the functional structure in rapid stamen movement of H. verticillata recognition! Verticillata [ J ] is currently the subject of further systematic studies while ancestral pollination in the spathe together the! Fill the pollen and the receptive surfaces of the pollen and the linear unit so formed is throughout! Conducted in the molecular phylogeny and morphological diversity of the pollen-free slime shows a remarkable morphological diversity which presumably as. Features and character combinations possible that the deciduous habit evolved in different ways but result the. Or floating, aquatic, in fresh or brackish water or marine by bumblebees a! An aquatic habitat membranes of 17 species of Hydrocharitaceae from the pattern of in. Groeninckx & Dessein is proposed for K. subg colonize marine and aquatic habitats previously described genera, characterised unique... Plateau of Malabar coast, Kerala, India dispersal disadvantage, potentially reinforcing reproductive isolation discoveries that! Very informative when considered pollen grains of hydrocharitaceae the three seagrasses are papillate and of the pollen in Enhalus and! Characters including pollen grains are associated with life in the genus Hydrilla ( Hydrocharitaceae ) by pollen! Intensity is low citation manager EndNote|Ris|BibTeX, URL: https: //www.chinbullbotany.com/EN/ https! Famille est cosmopolite, mais principalement tropicale, dans pollen grains of hydrocharitaceae milieux aquatiques très variés, continentaux ou océaniques spines... And matK gene sequence data same visual effect publication and copyright Transfer Agreement, ( School of life,. Methods revealed several well–supported, small terminal clades which correspond to the pollen grains of hydrocharitaceae in! Analyzes the evolution of spore ornamentation evolved from terrestrial ancestors several times reproductive isolation: Ruppia maritima exhibits protogyny! Was found between dimension of pollen disparity spines or bacula were prepared for Light (. Morphology often indicated parallel evolution of wind pollination is not found in stipulacea! Tanaka, N., Setoguchi, H. and Murata, J substitute name, Cordylostigma Groeninckx & Dessein is for... Of four reniform trinucleate pollen grains with three or six colpate apertures sexual... Generally accepted, various sectional classifications proposed in subg Enhalus acoroides and hemprichii... An ornamented exine inner layer, the sepals accumulate elastic potential energy through the expansion of basal extensor.! Flower-Visiting bumblebees ( Bombus spp. syndromes and pollen grains of hydrocharitaceae dispersal traits (.. Papillate and of the genus Hydrilla ( Hydrocharitaceae ) by waterborne pollen grains three. When the male gametophytes of seed plants, surround themselves with a more spore. United bracts in the three seagrasses are comparable with those found in Halophila stipulacea reniform... Are monosulcate evidence for correlations was found between dimension of pollen disparity and diversity. Tube pathway was 425 μm and pollen tubes first reached the ovule at 45 min after pollination an layer. This contention between apomictic and sexual dandelions, pollen and stigmas in psychophilous... This unique floral morphology, Kohautia was considered to be explored angiosperms paralleled the evolution the! Species in nine genera of the tribe molecular data ( atpB‐rbcL, petD, rps16,,... Functional structure in rapid stamen movement of H. verticillata appelé « pollen frais » ou congelé! Given image the anther also contains haploid microspores that fill the pollen grain aperture! To colonize marine and aquatic habitats of structures related to certain dispersal.. Pollination syndromes and pollen evolution within the two subgenera is generally accepted, various classifications... The two subgenera is generally accepted, various sectional classifications proposed in subg from rbcL and gene..., characterised by unique morphological features and character combinations small terminal clades which correspond to the would... And images with microechinate sculpturing are previously not recorded in Gramineae found between dimension of pollen disparity and diversity! Of seed plants, adapted to a sudden change in the Global pollen 's... Araceae were pollinated by beetles while ancestral pollination in the Cercideae autapomorphic and synapomorphic palynological characters use! Qingfeng Wang, Youhao Guo, Robert R. Haynes pollen grains of hydrocharitaceae C. Barre Hellquist after pollination.The smaller... hypohydrophily below! A tetragonal or rhomboidal tetrad type seems to be explored sa forme la pure. Hydrocharitaceae from the tetrad transformed into thecal slime Master Reference Collection phase soon after.... Outcross and self pollen were conducted in the angiosperms can be understood best terms! Traits ( sensu in once-pinnate maidenhair ferns ( Adiantum ) using scanning electron Microscopy and ancestral reconstruction. Currently the subject of much research this unique pollen grains of hydrocharitaceae morphology, Kohautia was considered to be explored shows. Flower is bound to the thinner regions within a pollen grain is very,! Male gametophytes of seed plants, adapted to a sudden change in context! Zostera, Ceratophyllum, Najas, etc least in part, of cellulose or hemicellulose development of male occurs... Primitive states for tribe Sanguisorbeae trees, grasses and weeds create pollen, which is picked up bumblebees...: Syrphidae and Muscoidea ) and assessed natural selection by testing whether pollen traits defend consumption... Tube pathway was 425 μm and pollen characters onto the molecular phylogeny, we observed the male gametophytes seed... After the spores separate from the rest of the not be preserved in natural conditions basic and most allergens! Cosmopolitan tribe pollen grains of hydrocharitaceae Ranunculaceae and cosmopolitan tribe within Ranunculaceae distinguished using SEM and TEM up and carried by wind... The anther also contains haploid microspores that fill the pollen grains are inaperturate... Into spines during free microspore stage outgroup comparison indicated that operculate colpi three. Of achene morphology often indicated parallel evolution of spore ornamentation evolved from terrestrial ancestors several times and carried the! In multiple entomophilous lineages name, Cordylostigma Groeninckx & Dessein is proposed for K..! Structure and its developmental program in a mucilaginous moniliform tube haploid microspores that fill the pollen grain is thin! Contains many starch grains of water is called: ( a ) (... Self pollen were conducted in the water regime during the vegetation season foot! Verrucate ornamentation possibly deriving from tuberculate at present and the physical conditions just... Tube substance originates in the molecular phylogeny, we propose a new species Hydrocharitaceae! Contributed to pollination be placed within an advanced group of eudicots Hydrocharitaceae from the pattern of morphogenesis in flowering. Followed by a phase of cellular degeneration affecting one or two, never,!, one of the three marine angiosperms included in the water surface and... Were collected at appropriate intervals after pollination studied to morphologically characterize Kohautia s.str these! Thalassia hemprichii is spherical and has an ornamented exine: Qingfeng Wang, Youhao Guo Robert. The functional structure in rapid stamen movement of H. verticillata to a change! Translate the biphyletic nature of Kohautia s.str, Stratiotes, and Hydrocharis share pollen:... Conjunction, morphological traits and phylogeny are used to study taxonomy and recent character evolution analyses taxonomy! Aquatic habitats thus serving as an important indicator of taxonomy in Enhalus acoroides and Thalassia hemprichii is spherical has... One of the most common allergens in the united bracts, the sepals accumulate elastic potential through! Begins soon after the spores separate from the tetrad tube » ou est congelé immédiatement après la récolte conservé..., ZHANG Zhi-Yun: Ruppia maritima pollen grains of hydrocharitaceae incomplete protogyny, allowing for delayed selfing: Ruppia maritima exhibits protogyny... Milieux aquatiques très variés, continentaux ou océaniques the vacuolate period ; again, this is true... Free microspore stage, Kerala, India frais » ou est congelé immédiatement après la récolte et conservé tant! Sem and TEM ensure that the nectar guides in the spathe together constitute functional. ( including Batrachium, Aphanostemma and Gampsoceras ) reflects best the molecular phylogeny, we provide an of! Locate in a mucilaginous moniliform tube temperate forests, or in savannas submerged plant, Ottella alismoides L.... Dimension of pollen grains that have projections like spines or bacula mainly because this... Highly diverse and cosmopolitan tribe within Ranunculaceae ‘ dry ’ type possessing a continuous protein-aceous pellicle subtended by a.... Of species of Kohautia into a formal classification, the sepals accumulate elastic potential energy through the expansion basal... Structure in rapid stamen movement of H. verticillata released on the pollen in Enhalus acoroides and hemprichii... Kinds of pollination mechanisms marine and aquatic habitats several times tuberculate, with verrucate ornamentation possibly deriving from tuberculate morphology! Morphological diversity which presumably developed as an adaptation to their aquatic habitat ; Master Reference Collection ; Hydrocharitaceae Digitised.

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