scholarly journals Disturbances in microsporogenesis and pollen grain development in Gagea lutea (L.) Ker. Gaw.

2012 ◽  
Vol 59 (1) ◽  
pp. 71-82 ◽  
Author(s):  
Ewa Szczuka ◽  
Jerzy Bohdanowicz ◽  
Joanna Świerczyńska ◽  
Jolanta Sobieska ◽  
Jacek Pietrusiewicz
Keyword(s):  
Abiotic Factors ◽  
Pollen Grains ◽  
Pollen Grain ◽  
External Factors ◽  
Grain Development ◽  
Excitation Light ◽  
Gagea Lutea ◽  
Microtubular Cytoskeleton ◽  
Sterile Pollen ◽  
Autumn And Winter

The meiotic division of microsporocytes and pollen grain development in <i>Gagea lutea</i> (L.) Ker.-Gaw. (Liliaceae) with fluorescence microscope (excitation light 400 nm) was observed after squashing the anthers in DAPI solution (fluorochrom dying DNA). Up to 70% of microsporocytes and pollen grains during the microsporogenesis and pollen grain development take a regular course. In the remaining microsporocytes and pollen grains (30%) the disturbances in course of both processes were observed. The most often observed disturbances are "late" chromosomes and a presence of micronuclei. The divisions of microsporocytes in the anther loculi show a big asynchrony, which, like the disturbances during the course of microsporogenesis and pollen grain development, may be caused by the external factors. The microsporogenesis takes place during autumn and winter months: the pollen grains develop in winter. At this time the dividing microsporocytes and developing pollen grains are under the influence of abiotic factors as low temperature and a lack of water. These factors disturb the formation of microtubular cytoskeleton of the dividing microsporocytes and pollen grains, which causes the formation of sterile pollen grains.

Pollination.

2021 ◽  
Author(s):  
Vicki Cottrell
Keyword(s):  
Abiotic Factors ◽  
Embryo Sac ◽  
Pollen Grains ◽  
Fruit Production ◽  
Pollen Grain ◽  
Egg Cell ◽  
Dispersal Mechanism ◽  
Haploid Male ◽  
Sterile Pollen ◽  
Pollen Formation

Abstract Pollination of flowers is the transfer of pollen grains (haploid male spores) from the anther (part of the androecium) to the stigma (part of the gynoecium) by biotic or abiotic factors (Sliwinska and Bewley, 2014). For seed and fruit production of agricultural crops the main pollinating agents are wind and insects (George, 2011). After a pollen grain is transferred to a receptive stigma, it absorbs water from the stigma surface and germinates. A pollen tube then grows down into the stigma, through the gynoecium and through the apical micropyle; from there it grows into an ovule in the ovary and double fertilisation then takes place. Two sperm are released into the embryo sac; one fertilises the ovule to produce a diploid zygote, and the other joins with two polar nuclei in the ovule to produce a triploid nucleus that will then develop into the nutrient-rich endosperm (Willmer, 2011). Pollen grain diameter is usually in the range 20-70 μm, and the surface structure and morphology varies considerably between plant species and dispersal mechanism (Wiltshire, 2010). Air temperature can have an effect on pollen formation and viability, with high temperatures potentially leading to sterile pollen (Bosland and Votava, 2012). Irradiated pollen grains are still able to germinate and produce pollen tubes that reach the ovule (Germana, 2012). Although they are unable to fertilise the egg cell, this process induces parthenogenesis and has been widely used to produce haploid fruits (Germana, 2012).

scholarly journals Quantitative methods in microscopy to assess pollen viability in different plant taxa

2020 ◽  
Vol 33 (3-4) ◽  
pp. 205-219
Author(s):  
Lorenzo Ascari ◽  
Cristina Novara ◽  
Virginia Dusio ◽  
Ludovica Oddi ◽  
Consolata Siniscalco
Keyword(s):  
Statistical Power ◽  
Quantitative Methods ◽  
Pollen Viability ◽  
Crop Improvement ◽  
Pollen Grains ◽  
Pollen Sterility ◽  
Pollen Grain ◽  
Automated Image Analysis ◽  
Future Research ◽  
Sterile Pollen

AbstractHigh-quality pollen is a prerequisite for plant reproductive success. Pollen viability and sterility can be routinely assessed using common stains and manual microscope examination, but with low overall statistical power. Current automated methods are primarily directed towards the analysis of pollen sterility, and high throughput solutions for both pollen viability and sterility evaluation are needed that will be consistent with emerging biotechnological strategies for crop improvement. Our goal is to refine established labelling procedures for pollen, based on the combination of fluorescein (FDA) and propidium iodide (PI), and to develop automated solutions for accurately assessing pollen grain images and classifying them for quality. We used open-source software programs (CellProfiler, CellProfiler Analyst, Fiji and R) for analysis of images collected from 10 pollen taxa labelled using FDA/PI. After correcting for image background noise, pollen grain images were examined for quality employing thresholding and segmentation. Supervised and unsupervised classification of per-object features was employed for the identification of viable, dead and sterile pollen. The combination of FDA and PI dyes was able to differentiate between viable, dead and sterile pollen in all the analysed taxa. Automated image analysis and classification significantly increased the statistical power of the pollen viability assay, identifying more than 75,000 pollen grains with high accuracy (R2 = 0.99) when compared to classical manual counting. Overall, we provide a comprehensive set of methodologies as baseline for the automated assessment of pollen viability using fluorescence microscopy, which can be combined with manual and mechanized imaging systems in fundamental and applied research on plant biology. We also supply the complete set of pollen images (the FDA/PI pollen dataset) to the scientific community for future research.

scholarly journals Optical and ultrastructural study of the pollen grain development in hermaphrodite papaya tree (Carica papaya L.)

2008 ◽  
Vol 51 (3) ◽  
pp. 539-545 ◽  
Author(s):  
Lídia Márcia Silva Santos ◽  
Telma Nair Santana Pereira ◽  
Margarete Magalhães de Souza ◽  
Pedro Correa Damasceno Junior ◽  
Fabiane Rabelo da Costa ◽  
...  
Keyword(s):  
Carica Papaya ◽  
Generative Cell ◽  
Pollen Grains ◽  
Male Gamete ◽  
Mitotic Division ◽  
Pollen Grain ◽  
Grain Development ◽  
Normal Pattern ◽  
Papaya Tree ◽  
Mother Cells

The objective of this study was to describe the pollen grain development in hermaphrodite papaya tree. The flower buds were collected at different stages of the development and the anthers were treated chemically for observation under optical and electronic transmission microscopes. The pollen grain development followed the normal pattern described for the Angiosperms. The pollen grain development was described from meiocyte to the mature pollen grain. In the microsporogenesis, the microspore mother cells or the meiocytes underwent meiosis giving rise to the tetrads that were enclosed by the calose. Later, the tetrads were released by the dissolution of the calose by calase activity and microspores underwent mitosis. Microgametogenesis was characterized by asymmetrical mitotic division of each microspore giving rise to bi-nucleate pollen grains. The structures similar to the plastids were found in the cytoplasm and close to the nucleus of the generative cell. Gradual degeneration was observed in the tapetum during the male gamete development.

scholarly journals Anomalous pollen grain development after nondifferentiating microspore division in Eremurus

2015 ◽  
Vol 46 (3) ◽  
pp. 459-469
Author(s):  
M. Charzyńska ◽  
J. Maleszka ◽  
B. Hon
Keyword(s):  
Mitotic Spindle ◽  
Generative Cell ◽  
Pollen Grains ◽  
Pollen Grain ◽  
Grain Development ◽  
Compact Structure ◽  
Cytoplasmic Rna ◽  
Ca 50 ◽  
Protoplast Division

Anomalous pollen grain development in <i>Eremurus</i> is caused by an anomalous position of the mitotic spindle and microspore protoplast division into two cells different than in differentiating division. The nuclei of the abnormal gametophytes are always spherical and that of the smaller of the two cells, notwithstanding the shape and position of the latter, has a more compact structure resembling rather that of the generative cell nucleus. Binucleate abnormal gametophytes always have equal nuclei. The wall separating the cells in abnormal pollen grains at first contains callose and, after disappearance of the latter, probably pectins and cellulose. Abnormal pollen grains contain less cytoplasmic RNA than normal ones arid most of them degenerate. If their viability is preserved they do not form' normal pollen tubes in vitro. The frequency of anomalous microspore division is higher in <i>E. robustus</i> (max ca. 50%) than in <i>E. himalaicus</i> (max. ca. 30%) and shows considerable seasonal variations. The results obtained suggest that disturbances in microspore development in <i>Eremurus</i> have a genetic background, but are stimulated by temperature variations in the period preceding mitosis in the microspore.

scholarly journals Male meiosis and pollen morphology in diploid Indonesian wild bananas and cultivars

The Nucleus ◽  
2021 ◽  
Author(s):  
Fajarudin Ahmad ◽  
Yuyu S. Poerba ◽  
Gert H. J. Kema ◽  
Hans de Jong
Keyword(s):  
Hybrid Sterility ◽  
Pollen Grains ◽  
Chromosome Analysis ◽  
Male Meiosis ◽  
Enzyme Treatment ◽  
Unreduced Gamete ◽  
Ploidy Levels ◽  
Scientific Disciplines ◽  
Sterile Pollen ◽  
Mother Cells

AbstractBreeding of banana is hampered by its genetic complexity, structural chromosome rearrangements and different ploidy levels. Various scientific disciplines, including cytogenetics, linkage mapping, and bioinformatics, are helpful tools in characterising cultivars and wild relatives used in crossing programs. Chromosome analysis still plays a pivotal role in studying hybrid sterility and structural and numerical variants. In this study, we describe the optimisation of the chromosome spreading protocol of pollen mother cells focusing on the effects of standard fixation methods, duration of the pectolytic enzyme treatment and advantages of fluorescence microscopy of DAPI stained cell spreads. We demonstrate the benefits of this protocol on meiotic features of five wild diploid Musa acuminata bananas and a diploid (AA) cultivar banana “Rejang”, with particular attention on pairing configurations and chromosome transmission that may be indicative for translocations and inversions. Pollen slides demonstrate regular-shaped spores except “Rejang”, which shows fertile pollen grains of different size and sterile pollen grains, suggesting partial sterility and unreduced gamete formation that likely resulted from restitutional meiotic divisions.

scholarly journals Meiosis and pollen grain development in Isolepis cernua f. cernua (Cyperaceae)

Caryologia ◽  
1999 ◽  
Vol 52 (3-4) ◽  
pp. 197-201 ◽  
Author(s):  
L.P. Dopchiz ◽  
L. Poggio
Keyword(s):  
Pollen Grain ◽  
Grain Development

scholarly journals Species Identification of Pinus Pollen Found in Belukha Glacier, Russian Altai Mountains, Using a Whole-Genome Amplification Method

Forests ◽  
2018 ◽  
Vol 9 (8) ◽  
pp. 444
Author(s):  
Fumio Nakazawa ◽  
Yoshihisa Suyama ◽  
Satoshi Imura ◽  
Hideaki Motoyama
Keyword(s):  
Species Identification ◽  
Whole Genome Amplification ◽  
Pollen Grains ◽  
Pollen Grain ◽  
Pinus Sibirica ◽  
Whole Genome ◽  
Accurate Identification ◽  
Closely Related Species ◽  
Genome Amplification ◽  
Amplification Method

Pollen taxa in sediment samples can be identified based on morphology. However, closely related species do not differ substantially in pollen morphology, and accurate identification is generally limited to genera or families. Because many pollen grains in glaciers contain protoplasm, genetic information obtained from pollen grains should enable the identification of plant taxa at the species level. In the present study, species identification of Pinus pollen grains was attempted using whole-genome amplification (WGA). We used pollen grains extracted from surface snow (depth, 1.8–1.9 m) from the Belukha glacier in the summer of 2003. WGA was performed using a single pollen grain. Some regions of the chloroplast genome were amplified by PCR, and the DNA products were sequenced to identify the pollen grain. Pinus includes approximately 111 recognized species in two subgenera, four sections, and 11 subsections. The tree species Pinus sibirica and P. sylvestris are currently found at the periphery of the glacier. We identified the pollen grains from the Belukha glacier to the level of section or subsection to which P. sibirica and P. sylvestris belong. Moreover, we specifically identified two pollen grains as P. sibirica or P. cembra. Fifteen species, including P. sibirica, were candidates for the remaining pollen grain.

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)

scholarly journals Pollen, Tapetum, and Orbicule Development inColletia paradoxaandDiscaria americana(Rhamnaceae)

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
M. Gotelli ◽  
B. Galati ◽  
D. Medan
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Pollen Grains ◽  
Pollen Grain ◽  
Ultrastructural Changes ◽  
Transmission Electron ◽  
The Family ◽  
Tapetal Cells ◽  
Grain Formation

Tapetum, orbicule, and pollen grain ontogeny inColletia paradoxaandDiscaria americanawere studied with transmission electron microscopy (TEM). The ultrastructural changes observed during the different stages of development in the tapetal cells and related to orbicule and pollen grain formation are described. The proorbicules have the appearance of lipid globule, and their formation is related to the endoplasmic reticulum of rough type (ERr). This is the first report on the presence of orbicules in the family Rhamnaceae. Pollen grains are shed at the bicellular stage.

scholarly journals Prunus necrotic ringspot virus Early Invasion and Its Effects on Apricot Pollen Grain Performance

2007 ◽  
Vol 97 (8) ◽  
pp. 892-899 ◽  
Author(s):  
Khalid Amari ◽  
Lorenzo Burgos ◽  
Vicente Pallas ◽  
María Amelia Sanchez-Pina
Keyword(s):  
Developmental Stages ◽  
Generative Cell ◽  
Pollen Grains ◽  
Growth Zone ◽  
Pollen Tubes ◽  
Climatic Conditions ◽  
Pollen Grain ◽  
Ringspot Virus ◽  
Prunus Necrotic Ringspot Virus

The route of infection and the pattern of distribution of Prunus necrotic ringspot virus (PNRSV) in apricot pollen were studied. PNRSV was detected both within and on the surface of infected pollen grains. The virus invaded pollen during its early developmental stages, being detected in pollen mother cells. It was distributed uniformly within the cytoplasm of uni- and bicellular pollen grains and infected the generative cell. In mature pollen grains, characterized by their triangular shape, the virus was located mainly at the apertures, suggesting that PNRSV distribution follows the same pattern as the cellular components required for pollen tube germination and cell wall tube synthesis. PNRSV also was localized inside pollen tubes, especially in the growth zone. In vitro experiments demonstrated that infection with PNRSV decreases the germination percentage of pollen grains by more than half and delays the growth of pollen tubes by ≈24 h. However, although PNRSV infection affected apricot pollen grain performance during germination, the presence of the virus did not completely prevent fertilization, because the infected apricot pollen tubes, once germinated, were able to reach the apricot embryo sacs, which, in the climatic conditions of southeastern Spain, mature later than in other climates. Thus, infected pollen still could play an important role in the vertical transmission of PNRSV in apricot.

Sign in / Sign up

Export Citation Format

Share Document