Pollen Dispersal in Natural Populations: A Method for Tracking Individual Pollen Grains

1979 ◽  
Vol 4 (3) ◽  
pp. 223 ◽  
Author(s):  
Danny C. Reinke ◽  
William L. Bloom
Keyword(s):  
Pollen Dispersal ◽  
Natural Populations ◽  
Pollen Grains

Insects facilitate wind pollination in pollen-limited Crateva adansonii (Capparaceae)

2011 ◽  
Vol 59 (1) ◽  
pp. 61 ◽  
Author(s):  
Yash Mangla ◽  
Rajesh Tandon
Keyword(s):  
Fruit Set ◽  
Pollen Limitation ◽  
Airborne Pollen ◽  
Pollen Dispersal ◽  
Natural Populations ◽  
Pollen Grains ◽  
Floral Biology ◽  
Wind Pollination ◽  
Reproductive Assurance

Low fruit-set in obligately outbreeding plant species is attributed to a variety of reasons that can be ascertained from reproductive studies. In the present work, the causes of poor natural fruit-set in Crateva adansonii DC. were investigated. Floral biology, the role of wind and insects in pollination and the breeding system of the species were studied in two natural populations for three consecutive seasons (2006–08). The flowers exhibited traits conducive to a mixture of wind and insect pollination (ambophily). Although a variety of insects visited the flowers, they were ineffective in pollinating. Nevertheless, active foraging by the honeybees (Apis dorsata, A. mellifera and A. cerana indica) facilitated enhanced pollen dispersal in the air and resulted in indirect pollination by wind. Airborne pollen grains pollinated the plants only up to 10 m. Fruit-set from open pollination was comparable to wind-pollinated flowers. Supplemental pollination treatments established the occurrence of strong self-incompatibility (SI) (index of SI = 0.14). Spontaneous autogamy was prevented by pronounced herkogamy. Low natural fecundity in C. adansonii is due to pollination failure, pollen limitation (pollen limitation index = 0.98) and the sparse distribution of the conspecifics; partial SI may partly ensure reproductive assurance through geitonogamy. In the absence of a pollinator wind appears to act as a secondary mode of pollination.

Spatial genetic substructure within natural populations of jack pine (Pinus banksiana)

1991 ◽  
Vol 69 (3) ◽  
pp. 547-551 ◽  
Author(s):  
Chang Yi Xie ◽  
Peggy Knowles
Keyword(s):  
Spatial Autocorrelation ◽  
Pinus Banksiana ◽  
Pollen Dispersal ◽  
Natural Populations ◽  
Jack Pine ◽  
Spatial Autocorrelation Analysis ◽  
Autocorrelation Analysis ◽  
Long Distance ◽  
Genetic Substructure ◽  
Good Agreement

Spatial autocorrelation analysis was used to investigate the geographic distribution of allozyme genotypes within three natural populations of jack pine (Pinus banksiana Lamb.). Results indicate that genetic substructuring within these populations is very weak and the extent differs among populations. These results are in good agreement with those inferred from mating-system studies. Factors such as the species' predominantly outbreeding system, high mortality of selfs and inbreds prior to reproduction, long-distance pollen dispersal, and the absence of strong microhabitat selection may be responsible for the observed weak genetic substructuring. Key words: jack pine, Pinus banksiana, genetic substructure, allozyme, spatial autocorrelation analysis.

Pollen biodiversity – why are pollen grains different despite having the same function? A review

2020 ◽  
Vol 193 (2) ◽  
pp. 141-164 ◽  
Author(s):  
Ettore Pacini ◽  
Gian Gabriele Franchi
Keyword(s):  
Pollen Dispersal ◽  
Pollen Grains ◽  
Reproductive Function ◽  
Female Competition ◽  
Size Number ◽  
Pollen Presentation ◽  
Dispersal Unit ◽  
Number Of Cells ◽  
Physiological Characters ◽  
Female Counterpart

Abstract The main morphological, cytological and physiological characters of ripe pollen are described, compared, analysed and discussed individually, in multiple combinations and in respect to the female counterpart and the biotic and abiotic components of the environment. This is to try to understand the reasons why pollen grains have the same reproductive function, but at dispersal are morphologically and physiologically different in many respects. The considered characters are: one or more types of grain per species; shape and size; number of cells; types of pollen dispersal unit; sporoderm stratification, furrows, colpori and other kinds of apertures; pollen presentation and array; water content percentage; and mature pollen reserves and osmotics. Some of the pollen features are correlated between themselves, some with the female counterpart or male and female competition, and others with the different components of the environment where the species lives, when it flowers and when pollen presentation occurs.

scholarly journals Morphology of Anemone sylvestris L. flower (Ranunculaceae)

2016 ◽  
Vol 75 (1) ◽  
pp. 74-80 ◽  
Author(s):  
Bożena Denisow ◽  
Sebastian Antoń ◽  
Małgorzata Wrzesień
Keyword(s):  
Seed Set ◽  
Pollen Dispersal ◽  
Pollen Grains ◽  
Starch Accumulation ◽  
Pollination Syndrome ◽  
Wind Pollination ◽  
Intermediate Form ◽  
Protected Species ◽  
Large Size ◽  
Opening And Closing

Abstract During the monitoring of populations of Anemone sylvestris L. (Ranunculaceae), a protected species in Poland, we found that the seed set is impaired. The flower is considered an adaptation that has coevolved to achieve effective pollination and successful fertilization. Therefore we have focused on the morphological and anatomical characteristics of the flowers of A. sylvestris L. as a prelude to the study of the species’ pollination biology and plant breeding system. The large size of the flower (50.6 ± 16.4 mm in dimensions) and its bowl shape fulfil both the biotic pollination syndrome and the aerodynamic requirements for pollen dispersal and capture. The opening and closing of the perianth provide a shelter for beetles. The odourless perianth, absence of nectar, scarcity of pollen (approximately 200 000 pollen grains per flower) and its traits - small size (axis P = 18.52 ± 1.0 μm; E = 16.59 ± 0.9 μm), lack of balsam on the exine surface, starch accumulation in more than 95% of pollen grains correspond to the specialization in anemophily. The stigma is papillous, the dense hairs are situated between single carpels indicating adaptation to capturing dry pollen and specialization in the wind pollination syndrome. The flower of A. sylvestris is an example for an intermediate form between entomophily and anemophily, i.e. a secondary and more advanced feature among Ranunculaceae.

Pollen dispersal and gene flow by pollen in Araucaria angustifolia

2003 ◽  
Vol 51 (3) ◽  
pp. 309 ◽  
Author(s):  
V. A. Sousa ◽  
H. H. Hattemer
Keyword(s):  
Gene Flow ◽  
Pollen Dispersal ◽  
Pollen Grains ◽  
Physical Characteristics ◽  
Araucaria Angustifolia ◽  
Effective Population ◽  
Pollen Dispersion ◽  
Biological Studies ◽  
Seed Dispersion ◽  
Dispersion Patterns

Araucaria angustifolia (Bert.) O.Ktze. is an economically important tree in southern Brazil. Indiscriminate exploitation is threatening this species with extinction. Conservation programs are urgently needed to save the remaining forest, and such programs must be guided by biological studies that genetically characterise the remaining populations. Pollen and seed dispersion patterns determine the distance of gene flow and directly influence genetic structure and effective population size. A. angustifolia is a wind-pollinated dioecious tree. For pollen-dispersal airflow, physical characteristics of pollen grain, such as size and shape, must be considered. The aim of this work was to determine the homogeneity of effective pollen clouds as well as to infer the physical characteristics of pollen. The homogeneity of pollen clouds of A. angustifolia was assessed for 70 trees of natural population in Brazil. Analysis of genetic variability and differentiation of the effective pollen clouds detected high diversity at the MDH-B and 6-PGDH-B loci. Heterogeneity G-tests indicated pollen pool heterogeneity in four of seven examined loci (GOT-B, PGM-A, SKDH-B and 6-PGDH-B). The pollen grains measured 61.50 μm. The floating rate ranged from 12.02 to 18.98 cm s–1. The physical characteristics of the pollen suggest that pollen dispersion is likely to be limited.

scholarly journals Reproductive Ecology of Male and Female Strobili and Mating System in Two Different Populations ofPinus roxburghii

2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
Chandra Mohan Sharma ◽  
Vinod Prasad Khanduri ◽  
Sunil Kumar Ghildiyal
Keyword(s):  
Mating System ◽  
Natural Populations ◽  
Production Capacity ◽  
Pollen Grains ◽  
Seed Orchard ◽  
Reproductive Period ◽  
Female Cone ◽  
Lower Altitude ◽  
Female Ratio ◽  
Male And Female

We studied several flowering traits, namely, male-female cone phenology, male-female cone production per tree, mating system, sex ratio, air-borne pollen grains and pollen migration, over four successive years in two different natural populations ofP. roxburghiifrom Garhwal Himalaya, India. Assessment of each trait mentioned except pollen dispersion was done by selecting five representative trees randomly in each population. The pollen migration was studied on naturally isolated source trees. The pollen trapping was done in all directions up to 2.5 km. The average reproductive period inP. roxburghiiwas 36 days with 3–5 days protandry. There were significant year and population effects for male and female cone output and pollen grains production per tree. In mass production year (1999), an average production of pollen cone per tree was estimated as42.44±8.32×103at lower altitude and28.1±0.89×103at higher altitude. The controlled pollination results in high level of outcrossing with 90% seed setting. We conclude that the high male-female ratio and tremendous pollen production capacity inP. roxburghiiindicate high male competition among trees within populations. The isolation strip of 600 m is considered minimal for the management of seed orchard.

Dioécie cryptique chez Geniostoma borbonica, espèce pionnière endémique de La Réunion

2003 ◽  
Vol 81 (9) ◽  
pp. 897-904 ◽  
Author(s):  
Laurence Humeau ◽  
Dominique Strasberg ◽  
Thierry Pailler
Keyword(s):  
Breeding System ◽  
Natural Populations ◽  
Pollen Grains ◽  
Floral Biology ◽  
Breeding Systems ◽  
Plant Succession ◽  
General Context ◽  
Cryptic Dioecy ◽  
Unisexual Flowers ◽  
Evolution Of Dioecy

In the general context of conservation of insular habitats, the floral biology, natural fecundity, and breeding system of Geniostoma borbonica (Lam.) Spreng. was studied in natural populations. The species, which was initially assumed to be gynodioecious, presents two kinds of individuals, both with morphological hermaphroditic but functionally unisexual flowers. Some individuals produce pollen grains, but neither ovules nor fruit, whereas other fructiferous individuals have anthers without pollen grains. Geniostoma borbonica is the first species in this genus to be reported as dioecious; its floral morphology illustrates an example of cryptic dioecy. This species combines an apomictic breeding system, assuring a fast installation without reproductive constraints, and a reproductive breeding system assuring maintenance of genetic variability in the population. These two breeding systems allow adaptation to evolution of the habitat during plant succession. This point is discussed in the colonization context of pioneer habitats, where herma- phro ditic species are recognized to be advantageous, as well as in the context of the evolution of dioecy in this genus.Key words: cryptic dioecy, pioneer habitat, oceanic island, Geniostoma.

scholarly journals Morphological differentiation of Primula veris L. pollen from natural and cultivated populations

2011 ◽  
Vol 73 (3) ◽  
pp. 229-232 ◽  
Author(s):  
Maria Morozowska ◽  
Krystyna Idzikowska
Keyword(s):  
Statistical Analysis ◽  
Natural Populations ◽  
Pollen Grains ◽  
Morphological Differentiation ◽  
Critical Test ◽  
Primula Veris ◽  
Comparative Statistical Analysis ◽  
Cultivated Populations ◽  
One Way Anova

Micromorphological characterisation and the comparative statistical analysis of the size of <em>Primula veris </em>L. pollen grains collected in three natural and three cultivated populations were done. Observations were carried out with SEM. The obtained measurements were analysed with the use of one-way ANOVA, Kruskal-Wallis Test and the Student-<em>t</em> Test. Pollen grains from long-styled ('pin') flower-morphs were mainly 6 colpate and from shortstyled ('thrum') flower-morphs 8 colpate. Colpi of some grains from 'thrum' flowers were 'sinuous' and 'circular', and they incised into the apocolpium zone. Ornamentation of 'pin' pollen grains was microreticulate, with lumina up to 0.8 μm wide, and for pollen grains from 'thrum' flowers was reticulate and eureticulate with lumina 1.1-1.7 μm wide. In lumina of mesocolpium area some free columellae were observed. Pollen grains from 'thrum' flower-morphs were more variable in size, both in natural and in cultivated populations, than grains from 'pin' flower-morphs. The differences in mean length (P) and breadth (E) of pollen grains from 'thrum' flowers collected in cultivated populations were statistically important (F<sub>P</sub> = 3.154 for the critical F<sub>005</sub> = 3.098; K-W<sub>e</sub> = 7.469 for the critical Test value <sub>α=005</sub> = 5.991). Pollen grains from 'thrum' flowers were bigger when coming from plants growing in natural populations (t<sub>E</sub> = 2.784 for the critical Test value <sub>α=005</sub> = 2.001).

scholarly journals MONOCOT POLLEN FLORA OF PASCHIM MEDINIPUR DISTRICT, WEST BENGAL WITH A NOTE ON POLLEN DISPERSAL MECHANISM

2017 ◽  
Vol 8 ◽  
Author(s):  
Arundhati Ghosh ◽  
Prakash Karmakar
Keyword(s):  
Light Microscopy ◽  
West Bengal ◽  
Pollen Dispersal ◽  
Pollen Grains ◽  
Surface Features ◽  
Dispersal Mechanism ◽  
Morphological Studies

<p>During the present investigation pollen morphological studies of 66 species belonging to 19 families of monocots in Paschim Medinipur district have been worked out by light microscopy. The studied families are Agavaceae, Amaryllidaceae, Arecaceae, Asphodelaceae, Cannaceae, Colchicaceae, Commelinaceae, Costaceae, Cyperaceae, Hemerocallidaceae, Hydrocharitaceae, Iridaceae, Liliaceae, Limnocharitaceae, Musaceae, Poaceae, Pontederiaceae, Typhaceae and Zingiberaceae. The apertural patterns are mostly belong to two different categories viz. monosulcate form (Agavaceae, Amaryllidaceae, Arecaceae, Asphodelaceae, Colchicaceae, Commelinaceae, Costaceae, Hemerocallidaceae, Hydrocharitaceae, Iridaceae, Liliaceae, Limnocharitaceae, Musaceae, Poaceae, Pontederiaceae) and anaporate type (Cyperaceae, Poaceae and Typhaceae). The shape of the pollen grains with monosulcate apertures are mostly oblate to peroblate type whereas taxa showing anaporate apertures are more or less spheroidal. Regarding the mode of pollen dispersal plant taxa with monosulcate apertures and apiculate surface ornamentations (e.g., reticulate, rugulate, spinulate, verrucate) are entomophilous (mainly melittophilous) whilest anaporate with smooth or minutely apiculate surface features are anemophilous. Here, entomophilous taxa provide rewards as pollen grains and nectar to the honeybee speecies, therefore, contribute as resource mobilizer for sustainance of honeybee colonies. </p>

scholarly journals The assessment of incompatibility and cross-compatibility in three populations of European globeflower (Trollius europaeus L.) by observing the pollen tubes growth

2017 ◽  
Vol 86 (2) ◽  
Author(s):  
Wojciech Antkowiak ◽  
Janetta Niemann ◽  
Andrzej Wojciechowski
Keyword(s):  
Natural Populations ◽  
Pollen Grains ◽  
Diallel Cross ◽  
Pollen Tubes ◽  
Small Degree ◽  
Trollius Europaeus ◽  
Cross Pollination ◽  
Cross Compatibility ◽  
Two Populations ◽  
Made In

<span>The European globeflower was shown to be highly self‐incompatible by flower bagging experiments, however, a very small degree of selfing was observed in natural populations. The present study is an attempt to evaluate the level of self-incompatibility (SI) in three <em>Trollius europaeus</em> populations from different sites of Poland and to assess a degree of cross-compatibility (CC) between these populations. The SI and CC of the globeflower populations were evaluated based on the pollen germination index (PGI). The observations of pollen grains germination and pollen tubes penetration were made in pistils after self- and diallel cross-pollination of globeflower plants. The pollination combinations which had the PGI equal or higher than 2 were regarded as compatible. Generally, the PGI after self-pollination of all globeflower population was over 2, indicating that they are self-compatible. Also, in two globeflower populations after cross-pollination the PGI was higher than 2 showing that there was cross-compatibility between plants of these two populations. However, the third population, from Biedrusko, was fully cross-incompatible.</span>

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