scholarly journals Ultrastructure of pollen grain sculpturing in several species of the Rosaceae family

2014 ◽  
Vol 51 (3-4) ◽  
pp. 341-344 ◽  
Author(s):  
Józef Kocoń ◽  
Stanisław Muszyński
Keyword(s):  
Pollen Grains ◽  
Sem Analysis ◽  
Pollen Grain ◽  
Chemical Plant ◽  
Plant Taxonomy ◽  
Finger Print ◽  
Prunus Spinosa ◽  
Rosaceae Family

The sculpturing patterns of pollen grains in some species of the <em>Rosaceae</em> family were analyzed by SEM. Three patterns are described, typical for <em>Prunus spinosa, Pyrus elengrifolia</em> and <em>Crataegus</em> sp. The role of SEM analysis of sculpturing patterns in taxonomy can be compared to the "finger print" method in chemical plant taxonomy.

Pollen morphology of the Rosaceae of western Canada. IV. Luetkea, Oemleria, Physocarpus, Prunus

1991 ◽  
Vol 69 (12) ◽  
pp. 2583-2596 ◽  
Author(s):  
R. J. Hebda ◽  
C. C. Chinnappa ◽  
B. M. Smith
Keyword(s):  
Pollen Morphology ◽  
Pollen Grains ◽  
Pollen Grain ◽  
Western Canada ◽  
Prunus Virginiana ◽  
Prunus Spinosa ◽  
Pore Area ◽  
Pollen Grain Size ◽  
Triple Points ◽  
Scanning Electron

Pollen grains of 12 species of western Canadian rosaceous genera, Luetkea, Oemleria, Physocarpus, and Prunus, were studied in the light microscope and scanning electron microscope. All pollen grains are produced as isopolar, radially symmetrical, usually tricolporate monads. Grains are predominantly spheroidal with a circular to triangular amb. Most of the species exhibit a well-developed chambered aperture complex at the equator, formed by a pair of sexinal flaps whereas in Prunus spinosa, Prunus americana, and Prunus virginiana the chamber is absent or weakly developed. Oemleria cerasiformis has no pore flaps. Apertures of Prunus emarginata and Prunus virginiana often have an equatorial bridge over the aperture complex. The exine of Prunus, Physocarpus, and Luetkea pollen is tectate perforate, like that of many Rosaceae. Sculpturing consists of ridges and valleys that form a striate to rugulate pattern. Ridges and valleys tend to be mainly parallel to the colpus but often loop near the poles. Pollen grains of Prunus spinosa are always rugulate or vermiculate with ridges arranged randomly. Oemleria cerasiformis pollen appears tectate imperforate. Ridges and valleys intersect at triple points in the subpolar region and curve in a semicircle around the pore area. On this basis Oemleria pollen is distinct from all other western Canadian Rosaceae. Pollen grain size ranges from small for Luetkea pectinata (17 μm in diameter) to medium for Prunus spinosa (36 × 33 μm). Key words: pollen morphology, Rosaceae, Western Canada, systematics.

Pollen-stigma interaction in Brassica oleracea: the role of stigmatic proteins in pollen grain adhesion

1980 ◽  
Vol 42 (1) ◽  
pp. 417-423
Author(s):  
A.D. Stead ◽  
I.N. Roberts ◽  
H.G. Dickinson
Keyword(s):  
Brassica Oleracea ◽  
Turnover Rate ◽  
Marked Decrease ◽  
Pollen Grains ◽  
Staining Intensity ◽  
Pollen Grain ◽  
Higher Plant ◽  
Adhesive Properties ◽  
Protease Treatment

The adhesion of pollen grains to the stigmas of Brassica oleracea was assayed after treatment of the stigmas wiuth protease and/or cycloheximide. Treatment with protease alone adversely affected pollen grain adhesion. However, the adhesive properties of the stigma recovered fully if the stigmas were not pollinated until 2 h after treatment. Immersion of the stigmas in cycloheximide after protease treatment prevented any recoveryt of the stigmas' adhesive properties. Cycloheximide treatment alone prevented pollen grain adhesion when pollination occurred later than 1–2 h after treatment but did not affect pollen grain adhesion if pollination occurred immediately after treatment. These results indicated not only that the surface-held proteins of the stigma are involved in pollen grain adhesion, but also that their turnover rate is rapid. Isoelectric focusing of extracts derived from stigmas after protease and cycloheximide treatment showed a marked decrease in staining intensity of 3 protein bands, one of which, a glycoprotein, is known to be present only when the self-incompativility system is fully functional. These observations suggest a specificity of adhesion between higher plant cells in the presence of the cell wall.

scholarly journals Characterization of the role of several COPI complex isoforms during the early acceptance of compatible pollen grains in Arabidopsis thaliana

2018 ◽  
Author(s):  
Daniel A. Cabada Gomez ◽  
M. Isabella Chavez ◽  
Emily Indriolo
Keyword(s):  
Pollen Tube ◽  
Seed Set ◽  
Contact Point ◽  
Pollen Grains ◽  
Retrograde Transport ◽  
Pollen Grain ◽  
Knock Out ◽  
Pollen Tube Penetration ◽  
Compatible Pollen

AbstractCOPI is a seven subunit coatomer complex, consisting of α, β, β′, γ, δ, ε, and ξ; in A. thaliana, COPI is necessary for retrograde transport from the Golgi to the Endoplasmic Reticulum, Golgi maintenance, and cell-plate formation in plant cells. Vesicle recruitment to the pollen contact point is required for pollen hydration and pollen tube penetration. To determine what other aspects of trafficking may be involved in the stigmatic papillae acceptance of compatible pollen, knock-out lines of several isoforms of the COPI complex were characterized in their roles during compatible pollination. Isoforms that were studied included α1-COPI, β-COPI, β′-COPI, γ-COPI and ε-COPI. Each mutant line was characterized in regards to pollen grain adherence, pollen tube penetration, and seed set. Of the mutant lines examined, α1-copi had the strongest phenotype with issues with compatible pollen grain adherence, tube germination and reduction in seed set while other lines had milder but visible retardation in compatible pollen acceptance. The data presented here are the first study of the role of the COPI complex in compatible pollinations and that certain subunit isoforms are required for compatible pollen acceptance.

scholarly journals Intracellular Amounts of Nucleic Acids and Protein During Pollen Grain Growth in Tradescantia

1958 ◽  
Vol 4 (4) ◽  
pp. 383-390 ◽  
Author(s):  
John W. Woodard
Keyword(s):  
Pollen Grains ◽  
Sole Source ◽  
Pollen Grain ◽  
Vegetative Nucleus ◽  
Rapid Decline ◽  
Chromosomal Protein ◽  
Cytochemical Analysis ◽  
Cytoplasmic Rna ◽  
Synchronous Development

The rapid growth, large organelles, and synchronous development of T. paludosa pollen grains make them ideal subjects for cytochemical analysis. A microphotometric study of the nucleoli, chromosomes, and cytoplasm fixed at daily intervals during pollen grain maturation indicated that: 1. DNA (Feulgen) synthesis in the generative nucleus occurred during the first third of interphase, while the DNA content of the vegetative nucleus remained unchanged. 2. Throughout development, changes in RNA (azure B) content, in general, paralleled changes in protein (NYS1, Millon) content in each organelle of the vegetative cell. Initially, the RNA and protein of all organelles increased up to mid interphase, when chromosomal and nucleolar fractions began to decline despite a continued increase in cytoplasmic RNA and protein. At least 24 hours before anthesis, the vegetative nucleolus had disappeared and chromosomal protein and RNA of the vegetative nucleus were apparently in rapid decline. Such a system offered an opportunity to study the role of the nucleus, especially the nucleolus, in RNA and protein metabolism in the cytoplasm, by noting what cytoplasmic processes could and could not continue at a time when nuclear mechanisms were absent or minimal. It was found that at least 2 fundamental processes continued during this period: both RNA and protein accumulated in the cytoplasm at a rapid rate. It was concluded that the nucleus is not the sole source of cytoplasmic RNA, for the data suggest that there are at least 2 separate and independent, or remotely dependent synthesizing systems, one nuclear and the other cytoplasmic. It is evident that nuclear influence on cytoplasmic synthesis need be neither direct nor immediate.

scholarly journals Differences in the structure of pollen in the ‘Senga Sengana’ and ‘Selva’ cultivars of Fragaria × ananasa

2020 ◽  
Vol 75 (4) ◽  
Author(s):  
IZABELA BORKOWSKA ◽  
MARCIN DOMACIUK ◽  
MARIA BERNAT
Keyword(s):  
Electron Microscope ◽  
Pollen Grains ◽  
Optical Microscope ◽  
Pollen Grain ◽  
Fragaria Ananassa ◽  
Arable Crops ◽  
Fertile Pollen ◽  
Rosaceae Family ◽  
Fresh Pollen ◽  
Scanning Electron

The strawberry belongs to one of the youngest species of arable crops. The study aimed to analyze pollen's structure in the ‘Senga Sengana’ and ‘Selva’ cultivars of Fragaria × ananassa. The strawberry is a dicotyledonous plant from the Rosaceae family. The article presents research carried out on Fragaria × ananassa cv. ‘Senga Sengana’ and ‘Selva’ collected during flowering. Pollen mor-phology was examined using a scanning electron microscope and a traditional optical microscope. The results showed that fresh pollen outnumbered dead pollen, confirming that the ‘Senga Sengana’ culti-var produces larger amounts of fertile pollen. Mature ‘Senga Sengana’ pollen grains are characterized by a specific sculpture of the exine walls. The analysis of Selva pollen grains revealed substantial changes in the structure of the sporoderm during its maturation. It becomes thicker and, as the size of the pollen grain increases, the exine layer becomes more elaborate.

scholarly journals A Duplicated Copy of the Meiotic Gene ZIP4 Preserves up to 50% Pollen Viability and Grain Number in Polyploid Wheat

Biology ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 290
Author(s):  
Abdul Kader Alabdullah ◽  
Graham Moore ◽  
Azahara C. Martín
Keyword(s):  
Pollen Viability ◽  
Pollen Grains ◽  
Wheat Chromosome ◽  
Grain Number ◽  
Meiotic Gene ◽  
Chromosome 5B ◽  
Mutant Pollen ◽  
Female Gametogenesis ◽  
Chromosome 3B

Although most flowering plants are polyploid, little is known of how the meiotic process evolves after polyploidisation to stabilise and preserve fertility. On wheat polyploidisation, the major meiotic gene ZIP4 on chromosome 3B duplicated onto 5B and diverged (TaZIP4-B2). TaZIP4-B2 was recently shown to promote homologous pairing, synapsis and crossover, and suppress homoeologous crossover. We therefore suspected that these meiotic stabilising effects could be important for preserving wheat fertility. A CRISPR Tazip4-B2 mutant was exploited to assess the contribution of the 5B duplicated ZIP4 copy in maintaining pollen viability and grain setting. Analysis demonstrated abnormalities in 56% of meiocytes in the Tazip4-B2 mutant, with micronuclei in 50% of tetrads, reduced size in 48% of pollen grains and a near 50% reduction in grain number. Further studies showed that most of the reduced grain number occurred when Tazip4-B2 mutant plants were pollinated with the less viable Tazip4-B2 mutant pollen rather than with wild type pollen, suggesting that the stabilising effect of TaZIP4-B2 on meiosis has a greater consequence in subsequent male, rather than female gametogenesis. These studies reveal the extraordinary value of the wheat chromosome 5B TaZIP4-B2 duplication to agriculture and human nutrition. Future studies should further investigate the role of TaZIP4-B2 on female fertility and assess whether different TaZIP4-B2 alleles exhibit variable effects on meiotic stabilisation and/or resistance to temperature change.

Biocompatibility Evaluation of Hollow Pollen Grains/Fe3 O4 Nanoparticles Composites as Potential Medical Devices

2021 ◽  
Author(s):  
Solmaz Zakhireh ◽  
Yadollah Omidi ◽  
Younes Beygi-Khosrowshahi ◽  
Ayoub Aghanejad ◽  
Jaleh Barar ◽  
...  
Keyword(s):  
Morphological Analysis ◽  
Pollen Grains ◽  
Building Blocks ◽  
Drug Carriers ◽  
Sem Analysis ◽  
Narrow Region ◽  
In Vitro Biocompatibility ◽  
Apoptosis Related Gene

Recently, pollen grains (PGs) have been introduced as drug carriers and scaffolding building blocks. This study aimed to assess the in-vitro biocompatibility of Pistacia vera L. hollow PGs/Fe3O4 nanoparticles (HPGs/Fe3O4NPs) composites using human adipose-derived mesenchymal stem cells (hAD-MSCs). In this regard, iron oxide nanoparticles (Fe3O4NPs) were assembled on the surface of HPGs at different concentrations. The biocompatibility of the prepared composites was assessed through MTT assay, apoptosis-related gene expression and field emission scanning electron microscopy (FE-SEM) analysis. Compared to the bare HPGs, the HPGs/Fe3O4NPs exhibited a biphasic impact on hAD-MSCs. The composite containing 1% Fe3O4NPs demonstrated no cytotoxicity up to 21 days while higher Fe3O4NPs contents and long-term exposure revealed adverse effects on the hAD-MSCs’ growth. The obtained result was verified by the qRT-PCR and morphological analysis carried out through FE-SEM which suggests that a narrow region below 1% Fe3O4NPs may be the optimum choice for medicinal applications of HPGs/Fe3O4NPs microdevices.

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)

The influence of thickness of CrN coating on the durability of hot forging dies

2011 ◽  
Vol 1 (2) ◽  
Author(s):  
Jerzy Smolik
Keyword(s):  
Coating Thickness ◽  
Nitrided Layer ◽  
Hot Forging ◽  
Sem Analysis ◽  
Internal Stresses ◽  
Main Role ◽  
Hybrid Layer ◽  
Crn Coating ◽  
Forging Process

AbstractThis article presents results which enabled the determination of the role of CrN coating and the influence of its thickness on the effectiveness of hybrid layer “nitrided layer / CrN coating” in the process of increasing the durability of forging dies. Dies coated with hybrid layers “nitrided layer / CrN coating” with various CrN coating thickness were — after different maintenance periods — subjected to metallographic testing, 3D shape testing and SEM analysis. Hardness distribution was also determined. The obtained results revealed that for all tested dies, independently from CrN coating thickness, the main mechanisms of their destruction was mechanical and thermal fatigue, and plastic deformation. It has been shown that the main role of CrN coating in the hybrid layer ”nitrided layer / PVD coating” is to counteract a high temperature influence the source of which is forging on die material. In order to do so the CrN coating should be characterized by a considerably lower thermal conductivity coefficient to steel and low hardness so that it can efficiently resist fatigue processes in the forging process. Based on testing conducted by means of the sin 2 φ method, it was revealed that internal stresses are vitally important for CrN coating for fatigue resistance of hybrid layer ”nitrided layer / CrN coating” during the forging process.

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