Features Of Pollen Grains Research Articles

Pollen storage at low temperature as a procedure for the improvement of cold tolerance in spring rape, Brassica napus L.

AbstractThe possibility of selecting spring rape for cold tolerance at the mature pollen grain stage was studied by investigating the effects of pollen storage at low temperatures on the quality of pollen grains and on the cold tolerance of the plants generated from them. Pollen treatments of F1 hybrids affected fertilization ability much more than viability and even after 10 days storage at 3 or 10°C the pollen germination percentage was reasonably high. Pollen storage for 7 or 10 days at 3 or 10°C significantly increased the cold tolerance of F2 seed germination, with 3°C being more effective. Pollen storage for a shorter time had no effect upon the number of resulting genotypes tolerant to low temperature. This approach may be successfully applied in plant breeding to enrich segregating plant populations with cold‐tolerant genotypes.

Energy dispersive x-ray (edx) investigations on some apocynaceae pollen

Abstract Apocynaceae pollen and anthers (unacetolyzed) were analysed with a Cambridge S 200 scanning electron microscope equipped with an energy dispersive X-ray (EDX) unit. Pollen grains collected from herbarium sheets show a very similar distribution of their elemental content. In most cases, complete dried anthers and single pollen grains gave the same results. In all 21 species investigated, the presence and amount of P, S, Cl, K and Ca differs significantly in the three subfamilies of the Apocynaceae. Only, the Plumerioideae possess a distinct amount of Cl while all species of the Apocynoideae and Cerberoideae show a clear amount of S. Usually, the K peak is higher than the Ca signal in the Plumerioideae and Cerberoideae, which is reversal in the Apocynoideae. In neither case Si could be detected. It can be concluded that EDX derived characters of pollen grains may give valuable information to taxonomy. Advantages of this technique are the need for very little material (one pollen grain can be suffic...

Pollen Grain Granuloma: A new clinicopathologic entity

Chronic ulceration of the ankle developed in a woman who had been stepped on by a cow. Microscopic examination revealed a florid foreign body granulomatous reaction in which pollen grains were found both within giant cells and lying free in fibrous tissue. The grains resembled those of the Asteraceae, or Compositae, family. This is the first report of pollen grains associated with an invasive tissue process. The morphologic features of pollen grains and their differentiation from other foreign bodies are discussed.

The fossil floras of Kachchh- IV. Tertiary palynostratigraphy

The palynological work so far done on the various Tertiary sediments of Kachchh has been reassessed and new information added. Many genera have been redefined and new genera, viz., Intrareticulites, Retitribrevicolporites, Dermatobrevicolporites, Triangulorites, Arengapollenites, Minutitricolporites, Acanthotricolpites, Angulocolporites, Pseudonyssapollenites, Pilatricolporites, Tribrevicolporites, Triangulotricolporites, Retitetrabrevicoporites, Tripilaorites, Ligulifloraedites, Spinulotetradites, Verrudandotiaspora, Tricolporopilites, Tricolporocolumellites, Ratariacolporites, Plicatiaperturites, Palaeomalvaceaepollis, Pilapanporites, Verrupolyporites, Khariasporites, Magnamonocolpites and Hibisceaepollenites have been proposed. On the basis of relative frequency of all taxa the Matanomadh Formation (Palaeocene) has been divided into (i) Barren Zone, (ii) Dandotiaspora dilata Cenozone, (iii) Tricolpites minutus Cenozone, (iv) Couperipollis kutchensis Cenozone, and (v) Sponge spicules Zone; Naredi Formation (Lower Eocene) has been divided into (i) Lakiapollis ovatus Cenozone, and (ii) Lygodiumsporites lakiensis Cenozone. The Middle Eocene palynological assemblage has been divided into Proxapertites microreticulatus Cenozone for Harudi Formation and Cheilanthoidspora enigmata Cenozone for the Rataria bore-core. Maniyara Fort Formation (Oligocene) has been divided into (i) Operculodinium centrocarpum Cenozone, (ii) Trisyncolpites ramanujamii Cenozone, and (iii) Aplanosporites robustus Cenozone and Khari Nadi Formation (Miocene) has been classified into (i) Cordosphaeridium cantharellum Cenozone, (ii) Striatriletes susannae Cenozone, and (iii) Operculodinium israelianum Cenozone. Thus in total, there are approximately 179 spore-pollen species in Palaeocene, Lower and Middle Eocene, Oligocene and Miocene. Of them, 42 species are confined to Palaeocene, 39 species to Eocene, 25 species to Oligocene and 21 species to Miocene. The Lower Eocene has maximum number (113) of spore-pollen species. The population gradually decreases and in Miocene only three species of angiosperms are recorded. On the basis of morphological characters of spores and pollen grains the families Parkeriaceae, Amaranthaceae-Chenopodiaceae, Clusiaceae, Bombacaceae, Malvaceae, Acacieae, Caesalpiniaceae, Rhizophoraceae, Lecythidaceae, Meliaceae, Ctenolophonaceae, Polygalaceae, Alangiaceae, Apiaceae, Asteraceae, Poaceae and Arecaceae could be recognized. The palynological cenozones proposed in this paper have also been compared with other known assemblages from India.

Studies on the pollen morphology of someCapparis L. (Capparaceae) species

Pollen morphology of seven species ofCapparis L., has been studied using light microscope and scanning electron microscope. Ultra surface patterns coupled with endocolpium characters of pollen grains are useful for distinguishing the species.

In vitro germination and pollen tube growth of maize (Zea mays) pollen. IX. Pollen source genotype and nonionic surfactant interactions

Because of their structure and active metabolic state, pollen grains are vulnerable to any agent in the in vitro germination medium. Surfactants are used in biological systems to reduce surface tension but are also known to produce subtle biochemical effects. This study investigated the effect of three nonionic surfactants on the germination characteristics of pollen grains from three pollen source genotypes. Pollen grains from three single cross hybrids (Wf9 × H55, K64 × K55, Ky228 × Ky226) were cultured on an artificial medium (15% sucrose, 0.6% bacto-agar, 0.03% calcium nitrate, 0.01% boric acid) supplemented with all possible combinations of three concentrations (10, 100, 1000 ppm, v/v) of the following surfactants: (i) Tween 80 (polyoxyethylene sorbitan monooleate); (ii) X-114 (alkyl phenoxypolyethoxy ethanol); and (iii) commercial sticker spreader (alkyl olefin aromatic polymers). A control containing no supplement was included. Over all genotypes, increasing concentrations of Tween 80 had the least effect on the germination characteristics measured (germination and ruptured percent, pollen tube length at 1, 2, and 3 h after inoculation) and X-114 had the greatest effect with no germination found above 10 ppm. For most of the germination characteristics, highly significant pollen source genotype X concentration interactions were found for each surfactant. The direction and magnitude of the surfactant effects depended on the surfactant, its concentration, the germination characteristic involved, and the pollen source genotype.

S-Gene action and the significance of characters in the heterostylous syndrome

Heteromorphic characters of stigmas and pollen grains participate in the physiological mechanism of incompatibility. This points to incompatibility as a major factor in the evolutionary moulding of pollen and stigmas. A first reconstruction of S-gene action shows that it controls normal growth and differentiation of floral parts. The S gene operates through a stepwise progression of events. The independently mutable subunits of the S gene revealed by breakdowns of the heterostylous syndrome control stages in the chain of activities of the gene. Inception of pollen size heteromorphism during early meiosis indicates that sporophytic incompatibility factors may be derived not only from the tapetum, but from the pollen mother cells as well. It is suggested that the differential growth of styles and stamens in the morphs mediates the production of chemical recognition specificities and that metabolism related to wall extension plays an important role in incompatibility. The physiological basis of differential growth control in the morphs and the significance of pollen size heteromorphism are discussed.

In vitro germination and pollen tube growth of maize (Zea mays) pollen. III. The effect of pollen genotype and pollen source vigor

Pollen grains from three inbreds (H49, H55, and H50) and two of their single cross hybrids (H49 × H55 and H49 × H50) were cultured on an artificial medium containing 15% sucrose and 0.6% bactoagar supplemented with all possible combinations of two levels (0.00 and 0.03%) of calcium nitrate (Ca) and two levels (0.00 and 0.01%) of boric acid (B). For all characteristics measured (germination percentage, germination with more than one pollen tube percentage, rupturing percentage, length and growth rate of the pollen tubes), significant differences between inbreds were obtained on most combinations of Ca and B. Since the inbreds were presumably homozygous and, as a result, each produced pollen grains of only one genotype, these differences in germination characteristics were apparently produced by the genetic differences between the inbreds. Therefore, the in vitro germination characteristics of pollen grains are associated with pollen genotype. The response of the hybrids could not be accurately predicted from the behavior of their inbred parents. In general, the hybrid mean was in the range between the means for the two inbred parents. However, the value of the mean for the hybrid relative to the values of the parental means depended on which hybrid combination was involved. The results indicated that the germination characteristics of pollen grains on various combinations of Ca and B are influenced in large part by pollen genotype but that the genetic expression is quite complex. Vigor of the pollen source per se was not a factor.

Pollen morphology of some Turkish <i>Campanula</i> spp. and their taxonomic value

Detailed pollen morphological structures of 12 Turkish species of Campanula L., e.g. C. argaea, C. cymbalaria, C. glomerata subsp. hispida, C. latiloba subsp. latiloba, C. lyrata subsp. lyrata, C. olympica, C. persicifolia, C. pterocaula, C. rapunculoides subsp. cordifolia, C. rapunculus var. rapunculus, C. stricta var. stricta, C. pamphylica subsp. tokurii have been studied under light (LM) and scanning electron microscopes (SEM) for the first time. LM and SEM investigations show that the pollen grains of 12 taxa are more or less oblato-sphaeroidal, triporate (and/or tetraporate), tectum-scabrate, or with circular amb. The exine sculpture is granulate-scabrate in C. argaea, C. lyrata subsp. lyrata, C. stricta var. stricta, C. glomerata subsp. hispida and C. pamphylica subsp. tokurii; but those of C. cymbalaria, C. latiloba subsp. latiloba, C. olympica, C. persicifolia, C. pterocaula, C. rapunculoides subsp. cordifolia and C. rapunculus var. rapunculus are rugulate-scabrate. Â Key words: Campanula, Pollen grains, Pollen morphology doi:10.3329/bjb.v37i1.1561 Bangladesh J. Bot. 37(1): 33-42, 2008 (June)

Etude morphologique des grains de pollen appartenant au groupe des Circumpolles (Pflug) Klaus dans le Jurassique de l'Aquitaine occidentale

An attempt is made to analyse sixteen characteristics of pollen grains referring to the Circumpolles Klaus group in the jurassic sediments. That investigation brings the inference that the systematics of this group must be related to the stratigraphy. Each morphological taxon distinguished by its variation magnitude and its geographical distribution assumes then a stratigraphic and biological value.

Spores and pollen grains of water plants and their dispersal

The group of the aquatic plants, comprising more than 2000 species, forms an interesting biological association of heterogenous elements which often are unrelated. This paper gives an account of the spores in aquatic liverworts, non-fern pteridophytes, water ferns, and angiosperms. These plants show different degrees of aquaticism and they determine the mode of dispersal of their spores and pollen grains. In truly aquatic plants, the exosporium is simple and thin-walled. The spores or pollen grains in them are short-lived and germinate quickly. They are dependent on water for dispersal. On the other hand, in semi-aquatic or facultatively aquatic plants, the pollen grains and spores have a thick exosporium. Their dispersal is either by insects or wind. Some of the water plants seem to have become secondarily adapted to an aquatic habitat. Their transition was from animophily to entomophily or from entomophily to partial hydrophily. They seem to have developed special adaptations for such transitions. The water ferns with their well developed exosporium and modified perisporium have special adaptations and special dispersal mechanisms. These have helped them in their survival from the Early Tertiary to the present times. A large number of aquatic angiosperms belong to the monocotyledons. They seem to have deviated from the great Ranalian plexus at a very early stage in evolution, on account of which their pollen-grain characteristics resemble those of primitive families of the Ranales. Despite their excellent adaptation to the water habitat, reflected in their vegetative characters, they are quite conservative in their pollen-grain characters and their pollinating and dispersing mechanisms.

Pollen grains in Palmae

The paper gives an account of Palmae pollen grains, which usually have a smooth sporoderm but rarely are spiny or warty. The sporoderm is spiny in the Pandanaceae and smooth in the Sparganiceae, families closely related to the Palmae. The classification of the Palmae into subfamilies as given by Drude (1889) and Moore (1960) has been taken as standard, and the characteristics of pollen grains in various genera belonging to these have been compared. Apart from shape, size, polysporic or unisporic nature of the pollen grains, single double nuclei at the time of shedding, it is thought that more reliable characteristics for classification and phylogeny are the number and nature of the colpi. There is a strong correlation in the primitive nature of monocolpate pollen grains among many species of Cocos, but not in all species believed to belong to that genus. For example, C. schizophylla has a triradiating colpus, considered to be primitive. This agrees with the view expressed by Beccari (1917) and Beccari and Pichi-Sermolli (1956) regarding the redistribution of species of this genus. That Nipa is a distinct, isolated member of the Palmae is supported by its non-colpate pollen grains. In the closely related tropical palm, Phytelephas macrocarpa, pollen grains are monocolpate. These two members thus seem to be unrelated, a conclusion further supported by morphology, anatomy, and embryology. Palynologically and anatomically, Nipa shows affinities with the related families Pandanaceae, Aroideae, and Cyclanthaceae.

A tentative code of the ancient and derivative characters of pollen grains of Angiosperms

For any studies in the comparative morphology of pollen, as well as for any application of palynological data to plant taxonomy, phylogeny and palaeopalynology it is very important to be able to estimate the antiquity of the more recency of characters.
 The palynological code proposed is the first step in this direction. Similar codes have been published earlier by other authors for both vegetative and generative organs of Angiosperms.
 For the establishment of the antiquity of characters it is necessary to take into consideration the phenomenon of heterochrony; therefore, not a single character, but as many as possible should be used.

THE USE OF POLLEN MORPHOLOGY IN THE TAXONOMY OF DICENTRA

Stern, Kingsley R. (Chico State Coll., Chico, Calif.) The use of pollen morphology in the taxonomy of Dicentra. Amer. Jour. Bot. 49(4): 362–368. Illus. 1962.—The pollen morphology of Dicentra has proved to be of great interest because of interspecific differences in surface character istics of pollen grains in all but 2 instances within the genus. Descriptions of the pollen of the 19 species and a key based on pollen morphology are given. Correlations between pollen morphology and gross morphology and anatomy are discussed, and phylogenetic trends are indicated.

カヤツリグサ科の分類学的研究 5

1. In this article, the author intended to divide the Genus Cladium in a wide meaning into two natural groups, Cladium sensu stricto and Machaerina, by their morphological characters including the pollen grains.2. In the former group, leaves are coriaceous, dorsiventrally flattened and always 3-ranked, and achenes are somewhat drupe-like and not crowned by distinct beak at apex, whereas the latter has bilaterally compressed or terete leaves usually 2-ranked and has achenes crowned by a distinct beak often scabrous at tip.3. This division also very well agrees with the features of pollen grains, which are represented by 1-6-aperturate type in the former and polyforate type in the latter.4. Concerning the generic name of the latter, Vahl's Machaerina is legitimate.

POLLEN STUDY IN RELATION TO BEE PASTURAGE

The importance of a full knowledge of bee pasturage is well known to the practical bee-keeper. Almost complete treatises about bee flora exist in all the chief honey producing countries. So far as South India is concerned, the industry is still in its infancy. Except for the records of Ramachandran (1937) and Venkatasubbayya (1938), no detailed informa- tion appears to be available and the present study was undertaken to supple- ment the information provided by them. But the attempt to ascertain plant sources for honey and pollen has in almost all studies reported in India, mainly been confined to the location of flowers actually visited by bees. This method cannot be deemed satis- factory, for it may be that plant sources growing at a long distance away from the apiary are missed. Also the worker's personal prejudices as to the usefulness or otherwise of a particular source may sometimes vitiate the reliability or completeness of the list of plants arrived at. The study of the external morphology of pollen grains has always formed a subject of absorbing interest to botanists. Pope (1925) and Wode- house (1928 and 1935) have studied the morphological features of pollen grains which are characteristic of the several families, the genera and the species of plants. From their observations, it seems possible that such characters as the size and shape of the pollen grains, the number and arrangement of germ pores and furrows, the character of reticulations and of spines, and the texture of the surface can be utilized in ascertaining bee pasturage. The present author is not aware of any work in which the pollen characters have been utilized for ascertaining bee pasturage in India. From the observations made on the pollen carried by the bees, the plants that are visited by them have been located and the seasons and the hours during which such visits are made have also been determined.

The Phylogenetic Value of Pollen-grain Characters

Journal Article The Phylogenetic Value of Pollen-grain Characters Get access ROGER P. WODEHOUSE ROGER P. WODEHOUSE Search for other works by this author on: Oxford Academic PubMed Google Scholar Annals of Botany, Volume os-42, Issue 4, October 1928, Pages 891–934, https://doi.org/10.1093/oxfordjournals.aob.a090149 Published: 01 October 1928