scholarly journals EL POLEN DE HELICTERES (STERCULIACEAE) y SU COMPARACIÓN CON GÉNEROS VECINOS

Bonplandia ◽  
2001 ◽  
Vol 11 (1-4) ◽  
pp. 207 ◽  
Author(s):  
Stella M. Piré ◽  
Carmen L. Cristóbal
Keyword(s):  
Pollen Grains ◽  
Pollen Grain ◽  
The Other ◽  
Type I ◽  
Evolutionary Trend ◽  
Equatorial Zone ◽  
Pollen Type ◽  
Type Viii ◽  
Exine Sculpture ◽  
Pollen Types

<p>Pollen grains of 41 species representing all seven sections of Helicteres were studied with light and scanning electron microscopy and described. In order to establish palynological affinities Neoregnellia cubensis, Kleinhovia hospita, Reevesia thyrsoidea, Veeresia clarkii, Ungeria floribunda and Pterospermum acerifolium were also examined. Helicteres is palynologically rather uniform with respect to the shape and size of the grains as well as the type and number of the apertures. The pollen grains are usually triporate, oblate or suboblate, amb triangular and medium sized. Nevertheless the exine surface shows great variability. Nine pollen types are recognized on the basis of the sculpture of the exine: Type 1, tectate-perforate, baculate, in sect. Helicteres; Type 11, tectate-perforate, psilate to weakly verrucate, in 4 species of sect. Orthocarpaea; Type 111, tectate-perforate, with the equatorial zone verrucate and the poles psilate, in sect. Stegogamos; Type IV, microreticulate, verrucate, in sect. Polyandria; Type V, tectate, scabrate, verrucate, in sect. Alicteres; Type VI, tectate-perforate, verrucate, in 2 species of sect. Orthocarpaeaand 4 species of sect. Orthothecium; Type VII, tectate-perforatefossulate, verrucate, the verrucae large, irregular in outline, often anastomosed, in 3 species of sect. Orthothecium; Type VIII, tectate to tectate-perforate-fossulate, perforations and fossulae as well as micro-verrugae and micro-echinae densely concentrated at the poles, the equatorial zone psilate or scabrate, in 3 species of sect. Orthothecium; Type IX, tectateperforate- fossulate, microechinate, the perforations and fossulae densely concentrated at the poles, the micro-echinae distributed throughout the surface but hardly differentiated on the poles, in 16 species of sect. Sacarolha and 5 species of sect. Orthothecium. The pollen types are ordered according to the complexity of the exine; with the types with uniform sculpture considered simpler and the types with polar and equatorial zones differentiated considered complex. Keys to identify the nine pollen types of Helicteres and the pollen types of related genera are presented. According to pollen morphology Neoregnellia is closely connected with Helicteres; this genus shares the same pollen type, IX, with sect. Sacarolha and some species of sect. Orthothecium. The pollens of Kleinhovia and Helicteres have many characters in common (shape, size, apertures), the only difference being the microreticulate surface of the former; they are rather close to each other. Reevesia thyrsoidea, Veeresia clarkii and Ungeria floribunda stand apart from Helicteres in having 3-5 brevi-colp(or)ate and suprareticulate grains. The very distinctive pollen of Pterospermum acerifolium (Iarge size, spheroidal, echinate) supports its segregation from the tribe Helictereae. In Helicteres the different patterns of exine sculpture have taxonomic and phylogenetic value. In the first place, they allow the recognition of the 4 monospecific sections (Helicteres, Stegogamos, Alicteres and Polyandria) and at the same time they reveal the coherence of the genus, since the other 3 sections which have many species (Orthocarpaea, Orthothecium and Sacarolha) are connected with each other not only by exomorphological characters but also by pollen characters. In the second place, they provide bases for interpreting infra-generic relationships and the possible origin of the genus.Two possible evolutionary trends of exine sculpture, which are representated in two diagrams, are proposed. The first possibility starts with the Type VI; from this pollen type the evolutionary trend would have diverged in several directions. On one side, a line would lead toward increasing complexity of the exine that would end in Type VIII. This kind of pollen grain would have given rise to Type IX. On the other side, several divergent lines might have taken place; modifications in the exine sculpture would have led toward a progressive simplicity that would culminate in the absence of sculptural elements of Type 11. From this kind of pollen grain Type I might have evolved. The second possibility starts from Type 11; in this case the evolutionary trend of the exine would have gone in only one direction; the exine would have acquired more and more complexity, giving rise to pollen types connected with each other by transitional forms.</p>

scholarly journals Pollen characters as taxonomic evidence in some species of Dipsacaceae from Iran

2017 ◽  
Vol 24 (2) ◽  
pp. 129-136 ◽  
Author(s):  
Ebadi-Nahari Mostafa ◽  
Nikzat-Siahkolaee Sedigheh ◽  
Eftekharian Rosa
Keyword(s):  
Pollen Morphology ◽  
Pollen Grains ◽  
Pollen Grain ◽  
Pollen Type ◽  
Upgma Tree ◽  
Pollen Characters ◽  
Exine Ornamentation ◽  
The Family ◽  
The World ◽  
Plant Taxon

Pollen morphology of nine species representing four genera: Cephalaria Schrad, Dipsacus L., Pterocephalus Vaill. and Scabiosa L. of the family Dipsacaceae in Iran has been investigated by means of scanning electron microscopy (SEM). The results showed that pollen grains were triporate and tricolpate. The pollen type of Scabiosa rotata Bieb. (tri- and tetraporate) is the first report in the world. The sizes of pollen grains fall into the classification group magna (pollen grain diameter 50–100 μm). Pollen shapes vary from preoblate to prolate and their polar views were triangulate and lobate. The exine ornamentation varies from gemmate in S. rotata to spinulate in the rest studied species. Species of Scabiosa have been dispersed in UPGMA tree that this confirmed the previous studies about taxonomic problems and species complexity in this genus. These results show the transfer of the some Scabisoa species to Lomelosia Raf. based on palynological characters. Pollen morphology of the family is helpful at the generic and specific level.Bangladesh J. Plant Taxon. 24(2): 129–136, 2017 (December)

Sporoderm morphogenesis in Euphorbia obesa and Croton gratissimus

Bothalia ◽  
1983 ◽  
Vol 14 (3/4) ◽  
pp. 849-856 ◽  
Author(s):  
M. L. Frean
Keyword(s):  
Pollen Morphology ◽  
Pollen Grains ◽  
Physiological Adaptation ◽  
Structure Characteristic ◽  
Pollen Type ◽  
Electron Microscope Level ◽  
Pollen Characters ◽  
Pollen Types ◽  
Unisexual Flowers ◽  
Taxonomic Grouping

Pollen grains of the Euphorbiaceae show a number of pollen types which can be clearly distinguished. Generally different genera are characterized by a specific pollen type.  Euphorbia obesa Hook. f. and Croton gratissimus Burch, subsp.  subgratissimus (Prain) Burtt Davy, represent two genera within the Crotonoideae with different morphology, each type characteristic for the respective genus. Taxonomically, the genus Euphorbia with apetalous flowers consisting of a naked pistil surrounded by several staminate flowers within a cyathium, is considered more advanced than the genus  Croton. In  Croton the inflorescence is a raceme with unisexual flowers. The floral whorls of the male show numerous anthers and both calyx and a showy corolla are present. Both genera are insect pollinated. In both  Euphorbia obesa and  Croton gratissimus the pollen wall in section shows columellae, a structure characteristic of angiosperms. However the present ontogenetic studies show that the formation of the columellae differs entirely in the two pollen types. The final stratification of the wall as well as the morphology of the grains differ and evaluation of the exine structure indicates that phylogenetically Croton pollen shows more advanced characters than  Euphorbia — contradicting the floral phylogeny. This study conducted at light and electron microscope level compares the two pollen types morphologically and ontogenetically, concentrating mainly on the formation of the exine which is tectate-perforate in the prolate tricolpate grain of Euphorbia obesa and semi-tectate in the anaperturate, spheroidal grain of Croton gratissimus. The aim of the study was to evaluate the significance of pollen characters in taxonomic and phylogenetic relationships within the Euphorbiaceae. The differing pollen morphology which is related to the taxonomic grouping of tribes within the subfamily (Crotonoideae) emphasizes diversity, which may result from physiological adaptation. The study shows that the same functional end may well be achieved in different ways and this may be a factor underlying the diversity in the heterogeneous family Euphorbiaceae.

scholarly journals Precise Pollen Grain Detection in Bright Field Microscopy Using Deep Learning Techniques

Sensors ◽  
2019 ◽  
Vol 19 (16) ◽  
pp. 3583 ◽  
Author(s):  
Ramón Gallardo-Caballero ◽  
Carlos J. García-Orellana ◽  
Antonio García-Manso ◽  
Horacio M. González-Velasco ◽  
Rafael Tormo-Molina ◽  
...  
Keyword(s):  
Network Architecture ◽  
Detection System ◽  
Pollen Grains ◽  
Pollen Grain ◽  
Average Value ◽  
Pollen Types ◽  
Pollen Concentrations ◽  
Pollen Counting ◽  
Estimation System ◽  
3D Information

The determination of daily concentrations of atmospheric pollen is important in the medical and biological fields. Obtaining pollen concentrations is a complex and time-consuming task for specialized personnel. The automatic location of pollen grains is a handicap due to the high complexity of the images to be processed, with polymorphic and clumped pollen grains, dust, or debris. The purpose of this study is to analyze the feasibility of implementing a reliable pollen grain detection system based on a convolutional neural network architecture, which will be used later as a critical part of an automated pollen concentration estimation system. We used a training set of 251 videos to train our system. As the videos record the process of focusing the samples, this system makes use of the 3D information presented by several focal planes. Besides, a separate set of 135 videos (containing 1234 pollen grains of 11 pollen types) was used to evaluate detection performance. The results are promising in detection (98.54% of recall and 99.75% of precision) and location accuracy (0.89 IoU as the average value). These results suggest that this technique can provide a reliable basis for the development of an automated pollen counting system.

scholarly journals Palynology of the Genus Stachytarpheta Vahl. (Verbenaceae)

2010 ◽  
Vol 2 (4) ◽  
pp. 27-33
Author(s):  
Olubukola ADEDEJI
Keyword(s):  
Cluster Analysis ◽  
Grain Size ◽  
Evolutionary History ◽  
Pollen Grains ◽  
Pollen Grain ◽  
The Other ◽  
Pollen Grain Size ◽  
Pollen Diameter ◽  
Stachytarpheta Cayennensis ◽  
Exine Morphology

The exine morphology of pollen grains of Stachytarpheta indica (Linn.) Vahl, Stachytarpheta cayennensis (Rich.) Vahl and Stachytarpheta angustifolia (Mill.) Vahl is reported. This study was carried out with a light microscope. Pollen grains from fresh anthers were collected and aceolysed. Statistical analysis used to analyse the data collected include cluster analysis, correlation analysis, similarity and distance indices. The pollen grains are spheroidal to oblate to sub-oblate in shape. They are aperturate, both colpate and porate. Tricolpate types occur most frequently, acolpate, monocolpate, bicolpate and tetracolpate types less frequently. The multicolpate and multiporate attributes in all the species indicate that the genus is not primitive in evolutionary history and this species probably, evolved around in the same time. According to the size, the pollen grains of the genus falls into groups permagna (pollen diameter 100-200 μm) and giganta (pollen diameter greater than 200 μm). S. cayennensis and S. anguistifolia belong to group permagna and S. indica only in the group giganta. This separates S. indica from the other two species. The large pollen grain size in the genus clearly supports the fact that the flowers in the genus are more insect-and-bird pollinated than wind pollinated. The similarity and distance indices of the species showed that S. cayennensis and S. angustifolia are the closest. S. indica is closer to S. angustifolia but farther from S. cayennensis.

scholarly journals Determination of Five Mineral Element Contents in Pollen Grains of Different Seedling Date Palm (Phoenix dactylifera L.) Male Trees Grown in Fayoum Governorate, Egypt

2019 ◽  
Vol 7 ◽  
pp. 16-25
Author(s):  
M.A. Seif El-Yazal ◽  
Samir A. Seif El-Yazal
Keyword(s):  
Date Palm ◽  
Pollen Grains ◽  
Dry Weight ◽  
Phoenix Dactylifera ◽  
Pollen Grain ◽  
The Other ◽  
Manganese Concentration ◽  
Regular Component ◽  
Mineral Element ◽  
Study Results

This experiment was conducted to found the connection between sensible male pollinators and the content from mineral element (Zinc, Irion, Manganese, Cupper and Magnesium) in pollen grain of fifty seedling date palm male and compared it with the best selective five seedling date palm males (number 2, 10, 29, 40, 46) are appropriate and promising males for to be utilized in pollinating female date palms and mistreatment in breeding programs in previous study. Results found variations among the categories of pollen and elements. The highest concentration of zinc was found in males' number (2, 10, 40 and 46) which recorded 127,102, 115 and 122 μg/g dry weight respectively as compared to the other male trees. Also the highest concentration of iron was found in male number (40) which recorded 222 μg/g dry weight as compared to the other male trees. Moreover, notes from result excellence male number (10) in manganese concentration which recorded 202 μg/g dry weight as compared to the other male trees. In this concern, pollen grain of date palm male trees contained also, high concentrations of copper and magnesium the concentration ranging from 10 to 30 and 1320 to 1985 μg/g dry weight for copper and magnesium respectively. The best result for copper and magnesium which obtained from the selective male number (46) which recorded 30 and 1985 μg/g dry weight for copper and magnesium respectively as compared to the other male trees. From all the results we can conclude that the date palm pollen grain was as rich source of important minerals, so its suitability as a regular component in plant and human diet.

Morphological studies of pollen grains of the Polish endemic species of the genus Rubus (Rosaceae)

Biologia ◽  
2012 ◽  
Vol 67 (1) ◽  
Author(s):  
Dorota Wrońska-Pilarek ◽  
Andrzej Jagodziński ◽  
Tomasz Maliński
Keyword(s):  
Pollen Morphology ◽  
Pollen Grains ◽  
Grain Morphology ◽  
Pollen Grain ◽  
Study Objective ◽  
Mean Values ◽  
Morphological Studies ◽  
Exine Sculpture ◽  
Pollen Grain Morphology

AbstractThe pollen of six taxa of the genus Rubus endemic to Poland (R. capitulatus, R. chaerophylloides, R. ostroviensis, R. posnaniensis, R. seebergensis and R. spribillei)was studied using light and scanning electron microscopy. The study objective was to extend the knowledge of the species pollen morphology and to investigate whether pollen morphology may help to taxonomically distinguish a very rare bramble species. Study material was derived from six natural localities where the species occur in the Wielkopolska region (Poland). Ten quantitative pollen grain features were analysed as well as the following qualitative ones: outline, shape, type of bridge and exine sculpture. Only mature, correctly formed pollen grains (30 per specimen) were measured and 180 pollen grains were examined in total. It was found that R. capitulatus and R. seebergensis had the highest mean values of P, E and Le features. In addition, pollen grains of R. capitulatus were most flattened (mean P/E ratio equals 1.14), while those of R. seebergensis were most elongated (mean P/E ratio equals 1.27). R. spribillei was the only species with striae of similar width as muri, whereas striae in the remaining species were wider. R. chaerophylloides and R. posnaniensis were characterised by specific, similar exine sculpture. Nevertheless, it should be stated that differences between pollen features of the species studied are so small and the variability of these features are so large that it is difficult to clearly identify the species studied. Therefore, pollen grain morphology can serve only as an auxiliary feature for the determination of these species.

The importance of being the first pollen in the strobili of Scots pine

2008 ◽  
Vol 38 (12) ◽  
pp. 2976-2980 ◽  
Author(s):  
Saila Varis ◽  
Arja Santanen ◽  
Anne Pakkanen ◽  
Pertti Pulkkinen
Keyword(s):  
Pinus Sylvestris ◽  
Scots Pine ◽  
Pollen Grains ◽  
Seed Orchard ◽  
Pollen Grain ◽  
Seed Orchards ◽  
Pollination Experiments ◽  
Seed Crop ◽  
Pollen Types ◽  
Pine Pollen

Timing of pollen arrival may affect the level of seeds fertilized by pollen from outside seed orchards, especially in seed orchards of Scots pine ( Pinus sylvestris L.) established in southern Finland with stock from northern populations. We performed sequential pollination experiments with Scots pine pollen collected from seed orchard clones originating from southern and northern Finland and recipient strobili in clones originating from southern Finland. When southern pollen was introduced first, seeds were sired equally by northern and southern genotypes. When northern pollen was introduced first, northern genotypes were found in 75% of the resulting seeds. When both pollen types were introduced at the same time, the resulting seed crop was split almost equally between northern and southern genotypes. These results do not unconditionally support the idea that the first pollen grain in the pollen chamber always fertilizes the ovum; instead, they suggest a more complex way of competition between pollen grains.

scholarly journals Pollen morphology of Amygdalus L. (Rosaceae) in Iran

2011 ◽  
Vol 79 (1) ◽  
pp. 63-71 ◽  
Author(s):  
Mahnaz Vafadar ◽  
Farideh Attar ◽  
Hosein Maroofi ◽  
Mansur Mirtadzadini
Keyword(s):  
Electron Microscopy ◽  
Pollen Morphology ◽  
Pollen Grains ◽  
Polar View ◽  
Pollen Grain ◽  
Type I ◽  
Type Ii ◽  
Type V ◽  
Scanning Electron ◽  
Section Level

Pollen grain of 16 species and three hybrids of the genus <em>Amygdalus</em> L., representing two subgenera and two sections distributed in Iran were examined by light and scanning electron microscopy. All pollen grains are tricolporate. The shape of grains varies from subprolate through prolate. Regarding outline, in polar view, pollen grains are triangular-circular and in equatorial view, elliptic. Regarding sculpturing of exine, the frequent type like many members of family <em>Rosaceae</em> is striate with or without perforations that can be subdivided into three subtypes: type I (A-B), type II (A-B) and type V. In three species, <em>A. trichamygdalus</em>, <em>A. spinosissima</em> and <em>A. orientalis</em>, exine sculpture type is completely different. In the first species is rugulate, in the second species is reticulate and in <em>A. orientalis</em>, it is gemmate-perforate. Ornamentation of ridges (muri) in the striate sculpture is parallel to ectocolpus. Number of perforations in tectum, diameter of them, striae intervals and the thickness of ridges varies among studied taxa. The striae have different depth and slope. Results showed that among pollen grain characters, shape is useful character solely for separating of taxonomic ranks in Iranian Amygdalus specially in subgeneric or section level.

Palynological analysis and taxonomic position of the genus Mertensia (Boraginaceae)

Botany ◽  
2012 ◽  
Vol 90 (8) ◽  
pp. 722-730 ◽  
Author(s):  
Tomoko Fukuda ◽  
Hiroshi Ikeda
Keyword(s):  
North America ◽  
Pollen Grains ◽  
The Other ◽  
Taxonomic Position ◽  
Western North America ◽  
Pollen Type ◽  
Palynological Analysis ◽  
Distinct Genus ◽  
Morphological Differences ◽  
Himalayan Species

Palynological analysis of the genus Mertensia Roth, s. lat. (Boraginaceae) was performed. All pollen grains studied were mostly dumbbell shaped and had 6-heteroaperturate pollen type without exception. The type of pollen of Mertensia does not contradict recent classifications that assign Mertensia to Cynoglosseae. Among six sections of Mertensia, pollen grains of section Oreocharis (the Himalayan Mertensia) were different from those of other sections in having granulate sculpturing on the colpus and pseudocolpus membranes. The results, along with other morphological differences, may support Riedl’s treatment of the Himalayan species of Mertensia in the distinct genus Pseudomertensia Riedl. Of the other sections, four monotypic sections (sections Steenhanmera, Neuranthia, Typomertensia, and Mertensianthe) showed pollen structures similar to each other. Pollen grains in section Eumertensia had some variations in size and ornamentation, especially in the species distributed in western North America.

Morphologie pollinique des Cupressaceae de l'est du Canada et du nord-est des États-Unis appliquée à l'étude des sédiments quaternaires

1990 ◽  
Vol 68 (1) ◽  
pp. 79-89 ◽  
Author(s):  
Johanne Parent ◽  
Pierre J. H. Richard
Keyword(s):  
Pollen Morphology ◽  
Pollen Grains ◽  
Taxodium Distichum ◽  
Juniperus Virginiana ◽  
Eastern Canada ◽  
Pollen Type ◽  
Thuja Occidentalis ◽  
Chamaecyparis Thyoides ◽  
Identification Criterion ◽  
Pollen Types

The pollen morphology of seven species, varieties and forms of Cupressaceae from eastern Canada and northeastern United States was studied by light microscopy, following acetolysis, to improve the identification of these taxa in Quaternary fossil sediments. Taxodium distichum (Taxodiaceae), which is also present in the study area, was included for comparison. Four pollen types were defined: Juniperus communis – Thuja occidentalis, Chamaecyparis thyoides, Juniperus horizontalis – Juniperus virginiana, and Taxodium distichum. Five shapes of pollen grains exist: whole, slightly split, opened in a "V" shape, spindlelike, or split in halves. All shapes are found in all species, in varying proportions, and represent different stages of hydration in Cupressaceae pollen type. The absence or presence of these shapes cannot be used as an identification criterion for the different species. A pollen identification key, applicable to fossil sediments and combining characters based on shape, size and other morphological features of acetolysed grains, is proposed and allows to differentiate all the species from one another, with the exception of Juniperus horizontalis and Juniperus virginiana.

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