This document discusses spores and pollen classification using the Numerical Palynological Classification (NPC) system. It describes how NPC classifies pollen and spores based on their aperture number, position, and character. The document outlines the merits of NPC as a simple and consistent classification system that allows for differentiation of plant groups. However, it also notes NPC is an artificial system and has limitations for types of pollen that do not fit its structure.
This is an excerpt of basic concepts and principles of palynology as it applies to systematics and taxonomy of plants. Credits are given to the authors and owners of photographs used in the entire presentation.
Palaeopalynology; Definition, History, Methods and Benefits of studyNipun Govind T
Note on what is palaeopalynology and its history, methods and Benefits of study
Father of palaeopalynology
Disciplines of Palynology
study of fossil pollen grains
Folli excavation
P. Reinsch
Sample mounting and observation
Palaeobotany
Barathiyar University palaeobotany
Lithological details , sedimentology
To trace the history of vegetation
To study plant assemblage at a specific stratigraphic horizon
To correlate deposits and assigning dates
To study climatic change
To study extinct genera
To study evolution of plants and establish affinity
To study past distribution of flora
To study palaeoecology
To determine coal-bearing strata
To define ancient shoreline
Palynologists have developed a series of standard methods that are applied to collect, extract, identify, and describe organic-walled microfossils.
Sample collection
Palynological Extraction
Palynological Sample Mounting and Observation
Palynological Analysis
The "Telome theory" of Walter Zimmermann (1930, 1952) is the most accepted theory that is based on fossil record and synthesizes the major steps in the evolution of vascular plants.
It describes how the primitive type of vascular plants developed from Rhynia like plants.
This is an excerpt of basic concepts and principles of palynology as it applies to systematics and taxonomy of plants. Credits are given to the authors and owners of photographs used in the entire presentation.
Palaeopalynology; Definition, History, Methods and Benefits of studyNipun Govind T
Note on what is palaeopalynology and its history, methods and Benefits of study
Father of palaeopalynology
Disciplines of Palynology
study of fossil pollen grains
Folli excavation
P. Reinsch
Sample mounting and observation
Palaeobotany
Barathiyar University palaeobotany
Lithological details , sedimentology
To trace the history of vegetation
To study plant assemblage at a specific stratigraphic horizon
To correlate deposits and assigning dates
To study climatic change
To study extinct genera
To study evolution of plants and establish affinity
To study past distribution of flora
To study palaeoecology
To determine coal-bearing strata
To define ancient shoreline
Palynologists have developed a series of standard methods that are applied to collect, extract, identify, and describe organic-walled microfossils.
Sample collection
Palynological Extraction
Palynological Sample Mounting and Observation
Palynological Analysis
The "Telome theory" of Walter Zimmermann (1930, 1952) is the most accepted theory that is based on fossil record and synthesizes the major steps in the evolution of vascular plants.
It describes how the primitive type of vascular plants developed from Rhynia like plants.
Embyrology in relation to Taxonomy. It is one of the concepts in Modern Taxonomy.in which embryological data is used to strengthen existing classification system.
In this presentation you will get to know about aspects of paleobotany, about coal and petroleum exploration and its extraction and how paleobotany is related to coal and petroleum.
Classification denotes the arrangement of a single plant or group of plants an distinct category following a system of nomenclature, and in accordance with a particular and well established plan.
Embyrology in relation to Taxonomy. It is one of the concepts in Modern Taxonomy.in which embryological data is used to strengthen existing classification system.
In this presentation you will get to know about aspects of paleobotany, about coal and petroleum exploration and its extraction and how paleobotany is related to coal and petroleum.
Classification denotes the arrangement of a single plant or group of plants an distinct category following a system of nomenclature, and in accordance with a particular and well established plan.
Applications of IR (Infrared) Spectroscopy in Pharmaceutical Industrywonderingsoul114
Various applications of IR (Infrared) Spectroscopy in Pharmaceutical industries related to drug discovery and structural elucidation is outlined in this presentation. Various qualitative and quantitative analysis of drug products are also outlined.
Palynology: History, branches, basic principles and application, collection o...Sangram Sahoo
Palynology: History, branches, basic principles and application, collection of polleniferous materials from modern samples (i.e. living flowers, spider webs, tree barks and honey samples) and sediments
1.plant systematic
levels of taxonomy
specie
specie concept
phases of taxonomy
components of taxonomy
2.palynological evidence
2. taxonomical evidence
3. chemotaxonomy
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Reproduction ensures continuity of species generation after generations as the older individuals undergo senescence and die. Flowering plants shows sexual mode of reproduction and bears complex reproductive units as male and female reproductive units along with accessary structures.
Flower is a modified stem which functions as a reproductive organ and produces ova and/or pollen. A typical angiospermic flower consists of four whorls of floral appendages attached on the receptacle: calyx, corolla, androecium (male reproductive organ consisting of stamens) and gynoecium (composed of ovary, style and stigma) .
Table of Contents:
a. Structure
b. Reproductive Structure
c. Androecium
d. Microsporogenesis
e. Gynoecium
f. Megasporogenesis
g. Pollination
h. Fertilization
i. Functions
Explore sexual reproduction in flowering plants notes to learn about the reproductive structure of the flower and the process of pollination.
From the forgoing presentation, it can be concluded that breeding characters viz., flowering period, inflorescence, time of flower opening, time of anther dehiscence, time of stigma receptivity, pollinating agent ,time of visitor of pollinating agent and fruit set (%) in tropical species are required to be studied as they are vital for any improvement and eco-environmental planning purposes. It also throws light on how species adopts itself along with the phenomenon of speciation and reproductive isolation. From these characters we can introduce new variety which is essential for further evaluation and also the identification of the interactions between biological factors, such as animal, plant species, and non-biological factors, like temperature, RH, rain and wind, helps us to elaborate management and conservation plans for the ecosystems of the planet, which have become more and more necessary due to highly increased rate of deterioration of different ecosystems during the last few decades.
What is greenhouse gasses and how many gasses are there to affect the Earth.moosaasad1975
What are greenhouse gasses how they affect the earth and its environment what is the future of the environment and earth how the weather and the climate effects.
Richard's entangled aventures in wonderlandRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
Introduction:
RNA interference (RNAi) or Post-Transcriptional Gene Silencing (PTGS) is an important biological process for modulating eukaryotic gene expression.
It is highly conserved process of posttranscriptional gene silencing by which double stranded RNA (dsRNA) causes sequence-specific degradation of mRNA sequences.
dsRNA-induced gene silencing (RNAi) is reported in a wide range of eukaryotes ranging from worms, insects, mammals and plants.
This process mediates resistance to both endogenous parasitic and exogenous pathogenic nucleic acids, and regulates the expression of protein-coding genes.
What are small ncRNAs?
micro RNA (miRNA)
short interfering RNA (siRNA)
Properties of small non-coding RNA:
Involved in silencing mRNA transcripts.
Called “small” because they are usually only about 21-24 nucleotides long.
Synthesized by first cutting up longer precursor sequences (like the 61nt one that Lee discovered).
Silence an mRNA by base pairing with some sequence on the mRNA.
Discovery of siRNA?
The first small RNA:
In 1993 Rosalind Lee (Victor Ambros lab) was studying a non- coding gene in C. elegans, lin-4, that was involved in silencing of another gene, lin-14, at the appropriate time in the
development of the worm C. elegans.
Two small transcripts of lin-4 (22nt and 61nt) were found to be complementary to a sequence in the 3' UTR of lin-14.
Because lin-4 encoded no protein, she deduced that it must be these transcripts that are causing the silencing by RNA-RNA interactions.
Types of RNAi ( non coding RNA)
MiRNA
Length (23-25 nt)
Trans acting
Binds with target MRNA in mismatch
Translation inhibition
Si RNA
Length 21 nt.
Cis acting
Bind with target Mrna in perfect complementary sequence
Piwi-RNA
Length ; 25 to 36 nt.
Expressed in Germ Cells
Regulates trnasposomes activity
MECHANISM OF RNAI:
First the double-stranded RNA teams up with a protein complex named Dicer, which cuts the long RNA into short pieces.
Then another protein complex called RISC (RNA-induced silencing complex) discards one of the two RNA strands.
The RISC-docked, single-stranded RNA then pairs with the homologous mRNA and destroys it.
THE RISC COMPLEX:
RISC is large(>500kD) RNA multi- protein Binding complex which triggers MRNA degradation in response to MRNA
Unwinding of double stranded Si RNA by ATP independent Helicase
Active component of RISC is Ago proteins( ENDONUCLEASE) which cleave target MRNA.
DICER: endonuclease (RNase Family III)
Argonaute: Central Component of the RNA-Induced Silencing Complex (RISC)
One strand of the dsRNA produced by Dicer is retained in the RISC complex in association with Argonaute
ARGONAUTE PROTEIN :
1.PAZ(PIWI/Argonaute/ Zwille)- Recognition of target MRNA
2.PIWI (p-element induced wimpy Testis)- breaks Phosphodiester bond of mRNA.)RNAse H activity.
MiRNA:
The Double-stranded RNAs are naturally produced in eukaryotic cells during development, and they have a key role in regulating gene expression .
Slide 1: Title Slide
Extrachromosomal Inheritance
Slide 2: Introduction to Extrachromosomal Inheritance
Definition: Extrachromosomal inheritance refers to the transmission of genetic material that is not found within the nucleus.
Key Components: Involves genes located in mitochondria, chloroplasts, and plasmids.
Slide 3: Mitochondrial Inheritance
Mitochondria: Organelles responsible for energy production.
Mitochondrial DNA (mtDNA): Circular DNA molecule found in mitochondria.
Inheritance Pattern: Maternally inherited, meaning it is passed from mothers to all their offspring.
Diseases: Examples include Leber’s hereditary optic neuropathy (LHON) and mitochondrial myopathy.
Slide 4: Chloroplast Inheritance
Chloroplasts: Organelles responsible for photosynthesis in plants.
Chloroplast DNA (cpDNA): Circular DNA molecule found in chloroplasts.
Inheritance Pattern: Often maternally inherited in most plants, but can vary in some species.
Examples: Variegation in plants, where leaf color patterns are determined by chloroplast DNA.
Slide 5: Plasmid Inheritance
Plasmids: Small, circular DNA molecules found in bacteria and some eukaryotes.
Features: Can carry antibiotic resistance genes and can be transferred between cells through processes like conjugation.
Significance: Important in biotechnology for gene cloning and genetic engineering.
Slide 6: Mechanisms of Extrachromosomal Inheritance
Non-Mendelian Patterns: Do not follow Mendel’s laws of inheritance.
Cytoplasmic Segregation: During cell division, organelles like mitochondria and chloroplasts are randomly distributed to daughter cells.
Heteroplasmy: Presence of more than one type of organellar genome within a cell, leading to variation in expression.
Slide 7: Examples of Extrachromosomal Inheritance
Four O’clock Plant (Mirabilis jalapa): Shows variegated leaves due to different cpDNA in leaf cells.
Petite Mutants in Yeast: Result from mutations in mitochondrial DNA affecting respiration.
Slide 8: Importance of Extrachromosomal Inheritance
Evolution: Provides insight into the evolution of eukaryotic cells.
Medicine: Understanding mitochondrial inheritance helps in diagnosing and treating mitochondrial diseases.
Agriculture: Chloroplast inheritance can be used in plant breeding and genetic modification.
Slide 9: Recent Research and Advances
Gene Editing: Techniques like CRISPR-Cas9 are being used to edit mitochondrial and chloroplast DNA.
Therapies: Development of mitochondrial replacement therapy (MRT) for preventing mitochondrial diseases.
Slide 10: Conclusion
Summary: Extrachromosomal inheritance involves the transmission of genetic material outside the nucleus and plays a crucial role in genetics, medicine, and biotechnology.
Future Directions: Continued research and technological advancements hold promise for new treatments and applications.
Slide 11: Questions and Discussion
Invite Audience: Open the floor for any questions or further discussion on the topic.
Earliest Galaxies in the JADES Origins Field: Luminosity Function and Cosmic ...Sérgio Sacani
We characterize the earliest galaxy population in the JADES Origins Field (JOF), the deepest
imaging field observed with JWST. We make use of the ancillary Hubble optical images (5 filters
spanning 0.4−0.9µm) and novel JWST images with 14 filters spanning 0.8−5µm, including 7 mediumband filters, and reaching total exposure times of up to 46 hours per filter. We combine all our data
at > 2.3µm to construct an ultradeep image, reaching as deep as ≈ 31.4 AB mag in the stack and
30.3-31.0 AB mag (5σ, r = 0.1” circular aperture) in individual filters. We measure photometric
redshifts and use robust selection criteria to identify a sample of eight galaxy candidates at redshifts
z = 11.5 − 15. These objects show compact half-light radii of R1/2 ∼ 50 − 200pc, stellar masses of
M⋆ ∼ 107−108M⊙, and star-formation rates of SFR ∼ 0.1−1 M⊙ yr−1
. Our search finds no candidates
at 15 < z < 20, placing upper limits at these redshifts. We develop a forward modeling approach to
infer the properties of the evolving luminosity function without binning in redshift or luminosity that
marginalizes over the photometric redshift uncertainty of our candidate galaxies and incorporates the
impact of non-detections. We find a z = 12 luminosity function in good agreement with prior results,
and that the luminosity function normalization and UV luminosity density decline by a factor of ∼ 2.5
from z = 12 to z = 14. We discuss the possible implications of our results in the context of theoretical
models for evolution of the dark matter halo mass function.
Cancer cell metabolism: special Reference to Lactate PathwayAADYARAJPANDEY1
Normal Cell Metabolism:
Cellular respiration describes the series of steps that cells use to break down sugar and other chemicals to get the energy we need to function.
Energy is stored in the bonds of glucose and when glucose is broken down, much of that energy is released.
Cell utilize energy in the form of ATP.
The first step of respiration is called glycolysis. In a series of steps, glycolysis breaks glucose into two smaller molecules - a chemical called pyruvate. A small amount of ATP is formed during this process.
Most healthy cells continue the breakdown in a second process, called the Kreb's cycle. The Kreb's cycle allows cells to “burn” the pyruvates made in glycolysis to get more ATP.
The last step in the breakdown of glucose is called oxidative phosphorylation (Ox-Phos).
It takes place in specialized cell structures called mitochondria. This process produces a large amount of ATP. Importantly, cells need oxygen to complete oxidative phosphorylation.
If a cell completes only glycolysis, only 2 molecules of ATP are made per glucose. However, if the cell completes the entire respiration process (glycolysis - Kreb's - oxidative phosphorylation), about 36 molecules of ATP are created, giving it much more energy to use.
IN CANCER CELL:
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
introduction to WARBERG PHENOMENA:
WARBURG EFFECT Usually, cancer cells are highly glycolytic (glucose addiction) and take up more glucose than do normal cells from outside.
Otto Heinrich Warburg (; 8 October 1883 – 1 August 1970) In 1931 was awarded the Nobel Prize in Physiology for his "discovery of the nature and mode of action of the respiratory enzyme.
WARNBURG EFFECT : cancer cells under aerobic (well-oxygenated) conditions to metabolize glucose to lactate (aerobic glycolysis) is known as the Warburg effect. Warburg made the observation that tumor slices consume glucose and secrete lactate at a higher rate than normal tissues.
A brief information about the SCOP protein database used in bioinformatics.
The Structural Classification of Proteins (SCOP) database is a comprehensive and authoritative resource for the structural and evolutionary relationships of proteins. It provides a detailed and curated classification of protein structures, grouping them into families, superfamilies, and folds based on their structural and sequence similarities.
Deep Behavioral Phenotyping in Systems Neuroscience for Functional Atlasing a...Ana Luísa Pinho
Functional Magnetic Resonance Imaging (fMRI) provides means to characterize brain activations in response to behavior. However, cognitive neuroscience has been limited to group-level effects referring to the performance of specific tasks. To obtain the functional profile of elementary cognitive mechanisms, the combination of brain responses to many tasks is required. Yet, to date, both structural atlases and parcellation-based activations do not fully account for cognitive function and still present several limitations. Further, they do not adapt overall to individual characteristics. In this talk, I will give an account of deep-behavioral phenotyping strategies, namely data-driven methods in large task-fMRI datasets, to optimize functional brain-data collection and improve inference of effects-of-interest related to mental processes. Key to this approach is the employment of fast multi-functional paradigms rich on features that can be well parametrized and, consequently, facilitate the creation of psycho-physiological constructs to be modelled with imaging data. Particular emphasis will be given to music stimuli when studying high-order cognitive mechanisms, due to their ecological nature and quality to enable complex behavior compounded by discrete entities. I will also discuss how deep-behavioral phenotyping and individualized models applied to neuroimaging data can better account for the subject-specific organization of domain-general cognitive systems in the human brain. Finally, the accumulation of functional brain signatures brings the possibility to clarify relationships among tasks and create a univocal link between brain systems and mental functions through: (1) the development of ontologies proposing an organization of cognitive processes; and (2) brain-network taxonomies describing functional specialization. To this end, tools to improve commensurability in cognitive science are necessary, such as public repositories, ontology-based platforms and automated meta-analysis tools. I will thus discuss some brain-atlasing resources currently under development, and their applicability in cognitive as well as clinical neuroscience.
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.Sérgio Sacani
The return of a sample of near-surface atmosphere from Mars would facilitate answers to several first-order science questions surrounding the formation and evolution of the planet. One of the important aspects of terrestrial planet formation in general is the role that primary atmospheres played in influencing the chemistry and structure of the planets and their antecedents. Studies of the martian atmosphere can be used to investigate the role of a primary atmosphere in its history. Atmosphere samples would also inform our understanding of the near-surface chemistry of the planet, and ultimately the prospects for life. High-precision isotopic analyses of constituent gases are needed to address these questions, requiring that the analyses are made on returned samples rather than in situ.
(May 29th, 2024) Advancements in Intravital Microscopy- Insights for Preclini...Scintica Instrumentation
Intravital microscopy (IVM) is a powerful tool utilized to study cellular behavior over time and space in vivo. Much of our understanding of cell biology has been accomplished using various in vitro and ex vivo methods; however, these studies do not necessarily reflect the natural dynamics of biological processes. Unlike traditional cell culture or fixed tissue imaging, IVM allows for the ultra-fast high-resolution imaging of cellular processes over time and space and were studied in its natural environment. Real-time visualization of biological processes in the context of an intact organism helps maintain physiological relevance and provide insights into the progression of disease, response to treatments or developmental processes.
In this webinar we give an overview of advanced applications of the IVM system in preclinical research. IVIM technology is a provider of all-in-one intravital microscopy systems and solutions optimized for in vivo imaging of live animal models at sub-micron resolution. The system’s unique features and user-friendly software enables researchers to probe fast dynamic biological processes such as immune cell tracking, cell-cell interaction as well as vascularization and tumor metastasis with exceptional detail. This webinar will also give an overview of IVM being utilized in drug development, offering a view into the intricate interaction between drugs/nanoparticles and tissues in vivo and allows for the evaluation of therapeutic intervention in a variety of tissues and organs. This interdisciplinary collaboration continues to drive the advancements of novel therapeutic strategies.
3. SPORES
Spores are reproductive haploid structures that is adapted
for dispersal and surviving for extended periods of time in
unfavorable conditions.
Spores form part of the life cycles of many plants, algae,
fungi and some protozoans.
A chief difference between spores and seeds as dispersal
units is that spores have very little stored food resources
compared with seeds.
4. Spores are usually haploid and unicellular and are
produced by meiosis in the sporophyte.
Once conditions are favorable, the spore can develop
into a new organism using mitotic division, producing
a multicellular gametophyte, which eventually goes on
to produce gametes.
5. POLLEN
Pollens are produced from the microspore mother
cells, but female spores are produced by the
megaspore mother cells
Pollen grains have two outer coats extine and intine
and female spores do not have the extine or intine.
Pollens are dispersed by various mechanisms, but
female spores are retained within the ovary.
6. Pollens are found inside the pollen sac, and female
spores are found inside the ovule.
In other words, all pollens are spores, but not all
spores are pollens.
7. NPC Classification
NPC is an artificial system of classification of pollen
and spore based on the three features of aperture only,
i.e. number, position and character.
Erdtman and Straka (1961) proposed NPC
classification and palynologists all over the world
accepted it.
According to NPC system each pollen grain has an
arithmetic cardinal number consisting of three digits
8. The first digit reveals the absence or presence of
aperture, and when present it mentions the total
number of aperture(s) present in a pollen grain
The second digit illustrates the position of aperture(s),
i.e. distal, proximal, and latitudinal, meridonial,
equatorial etc.
The microspores reveal the position of aperture(s)
with full clarity when they are in tetrad.
9. The third digit explains the character of an aperture,
i.e. circular/oval or elongated, simple or compound
etc. ‘N’ from number, ‘P’ form position and ‘C’ from
character of aperture compose the NPC-classification.
10. Classification of Aperture Based
on Number
In NPC system ‘N’ denotes the number of aperture(s)
present in a pollen grain.
Aperturate pollen, i.e. pollen having apertures are divided
into seven groups.
The groups are mentioned as N1 to N7.
Each group has characteristic number of aperture, i.e. N1 has
one aperture and N2 has two apertures and so on. The
N7 group has seven or more apertures
11. N1 to N7 groups are also referred to respectively as
monotreme, ditreme, tritreme, tetratreme,
pentatreme, hexatreme, and polytreme (Greek trema
means hole, opening, aperture; pl. tremata).
There are pollen grains where apertures are absent.
Such pollen grains are termed as inaperturate or
atreme and they are placed in N0group.
12. Another special group N8—termed anomotreme is
created where the pollen grains and spores have one or
several irregular or irregularly spaced apertures
13. Classification of Aperture Based
on Position
In NPC system ‘P’ denotes the position of aperture in a
pollen grain and spore.
The position may be proximal, distal and equatorial.
There are seven groups of aperture based on position
namely –P0 to P6. Pollen grains having P0 group have
uncertain or unknown position of aperture).
14. . P1 groups of pollen and spores are catatreme
Catatreme pollen grains have one aperture that occurs
on the proximal part of a grain.
The proximal part is the face of a pollen grain or spore
that faces inward/nearest or toward the centre of
tetrad .
15. P2 groups of pollen and spores are anacatatreme
Anacatatreme pollen and spores have two apertures.
One aperture with its centre occurs at the proximal pole.
The other aperture with its centre occurs on the distal pole
The distal part is the face of a pollen grain and spore that
faces outward, i.e. away from the centre of tetrad and
opposite the proximal part
16. P3 groups of pollen and spores are anatreme, i.e. the
aperture is distal in position.
P4 groups of pollen and spore are zonotreme.
A zonotreme pollen grain is characterized in having
apertures on equator or sub-equator
17. The equator is the part of a pollen grain or spore that runs
midway between the proximal and distal poles and
perpendicular to polar axis.
P5 groups of pollen and spore are dizonotreme
Dizonotreme pollen grains have apertures arranged in two
or more zones.
The apertures occur parallel to equator. P6 groups of pollen
and spore are pantotreme
18. Pantotreme pollen grains have apertures scattered over
the whole surface uniformly. As a rule, pantotreme
pollen grains are spheroidal.
19. Classification of Apertures Based
on Character
In NPC-system ‘C’ denotes the character of an aperture
in a pollen grain and spore.
The character groups of pollen and spore are seven and
they are mentioned as C0 toC6. C0 groups have
apertures whose character cannot be established with
certainty.
C1 groups of pollen and spore have leptoma (Greek
leptoma means thin place).
20. Leptoma is a thin area, aperture like and functions like
an aperture.
Pollen grains having one leptoma are termed as
monlept.
The leptoma may occur on either proximal-or distal
face of a pollen grain and spore and accordingly
termed as catalept and analept
21. . C2 groups are trichotomocolpate (Gr. Tricha, in three
parts; tome, cut; kolpos, depression, furrow).
Trichotomocolpate is a three- branched aperture, the
branches of which are more than two times longer
than breadth.
Trichotomocolpate pollen and spores having aperture
on porximal face are termed as trilete
22. The group C3 has colpate grains.
The group C4 comprises porate pollen grains.
The group C5 comprises colporate pollen.
The group C6comprises pororate pollen. C3, C4, C5 and
C6 groups of aperture are previously discussed under
aperture
23.
24. Merits of NPC classification:
It is a simple system of classification and illustrates the
apertures of a pollen grain and spore.
With the aid of NPC pollen grains and spores of
pteridophyta, monocotyledon and dicotyledon, to
some extent, can be differentiated.
Most of the spores of pteridophyta are monolete or
trilete.
25. Monocots are characterized by inaperturate, monosulcate
and monoporate pollen grains.
Dicots, with a few exceptions, have pollen grains that are
mostly with three meridonial furrows and polyaperturate.
Thus NPC narrows the search list of identification of
unknown sporomorphs
NPC makes the description of apertures precise.
26. NPC is supposed to be of primary classificatory
character because apertures are most conservative.
It is supplemented by surface ornamentation, size and
shape etc. of a pollen grain.
Sometimes it becomes possible to identify the family
or genus or even species of a pollen grain with the aid
of NPC in combination with other morphological
characters.
27. Palynologists all over the world accepted NPC-
classification as it is basically simple and consistent
where pollen grains and spores could be arranged
easily.
This helps to identify unknown sporomorphs
NPC, sporoderm stratifications, exine patterns, size
and shape etc. of a pollen grain are genetically stable.
28. This property is utilized for various purposes and the
followings are a few illustrations.
With the aid of NPC and other characters a key can be
formulated that helps to identify unknown pollen and
spores
NPC and the various types of exine patterns and
ornamentation provide characters of taxonomic
significance and thus become one of the sources of
alpha taxonomy
29. Demerits of NPC classification:
It is an artificial system of classification.
Syncolpate and parasyncolpate pollen grains do not fit
neatly in NPC system
Pollen grains that are characteristically present as
aggregates in tetrads, e.g. Ericaceae, Typhaceae and
polyads, e.g. Orchidaceae, Mimosa etc. are not
grouped in NPC system
30. NPC-system of classification is always compared with
Linnaeus’s system of classification, because the latter
is also an artificial system of classification.
The characters of stamen were the basis of
classification.
‘Linnaeus accepted the weakness of his classification
but claimed that it was propounded mainly as an aid to
identification’.
31. This is also applicable to Professor Erdtman.
Palynologists from every discipline of palynology
utilize Erdtman’s NPC classification
Other characters related to pollen morphology as an
aid to the identification of unknown sporomorphs.