Palynology studies palynomorphs, organic-walled microfossils including pollens and spores used in stratigraphy and palaeoecology. These microfossils are crucial in understanding plant life cycles, particularly the alternation between spore-producing sporophytes and gamete-producing gametophytes. The document discusses spore morphology, reproduction, and the structural differences of pollen grains, highlighting their significance in geological studies.

1. Palynology
The science of palynomorphs is known as
palynology
Palynomorphs
organic-walled microfossils between 5 and
500 µm in size, pollens, spores,
dinoflagellate cyst, acritarch, chitinozoans
and scolecodonts
Organic walled microfossils

2. Pollens and spores
Algae Brophytes Pteridophytes
Gymnosperms
Angiosperms

3. Angiosperms
spores
Pollens
Both have walls resistant to
microbial attacks and
temperature after burial
spores are produced by
bryophytes (e.g., mosses)
Pollens are produced by
angiosperms and confers
Produced in large number
Travel rapidly and widely in
wind and water
Brophytes Pteridophytes

4. Lakes
Ponds
Rivers Ocean
Settle down in ponds, rivers, lakes and oceans
Widely used in stratigraphy especially when correlating continental
and near shore deposits
Also used for palaeoecological and palaeoenvironmental studies

5. Life cycles of ‘lower’ land plants
Land plants differ from algae in being vascular
The life cycle alternate between a spore producing sporophyte and
gamete producing gametophyte generation
Spore producing: reproduce
asexually
Gamete producing:
reproduce sexually
Similar to algae in having alternation of generation
The sporophyte generation reproduce asexually and the gametophyte
generation reproduce sexually

6. Spore producing: reproduce
asexually
Gamete producing:
reproduce sexually
The sporophyte generation has diploid number (2N) of chromosome
where as the gametophyte generation has haploid number (N) of
chromosomes
The gametophyte has male (antheridia) and female (archaegonia)
reproductive organs.
The male organ (antheridia) reproduce sperms and the female organ
(archaegonia) reproductive eggs.

7. The biflagellate motile sperm is transferred in a moist environment to
the female reproductive organ (archaegonia) fertilize egg and zygote is
formed.
The zygote then grows by mitosis into a stalk capped by a sporangium.
The spore mother cells within the sporangium divide through meiosis
and haploid spores are formed.

8. The sporangium when riped releases the spores which again germinate
in a damp habitat growing into a prostrate protonema (a thread-like
chain of cells that forms the earliest stage (the haploid phase) of
a bryophyte life cycle.
Bryophytes living in dry environment have thick walled spores which
have the dormant capacity of long periods.

9. Life cycles of ‘lower’ land plants
Land plants differ from algae in being vascular
The life cycle alternate between a spore producing
sporophyte and gamete producing gametophye
generation
Spore producing: reproduce
asexually
Gamete producing:
reproduce sexually
Male
reproducti
ve organ
antheridia
Female
reproductiv
e organ
archegonia
Similar to algae in having alternation of
generation

10. Spore morphology
The shape, size, aperture and wall structure are used to describe the
morphology of a spore
A spore mother cell splits/divides into four smaller cells known as
tetrad

11. Tetrahedral tetrad
In tetrahedral tetrad each of the four
spores is in contact with the rest of the
three spores in a proximal face
proximal-nearest to the point
of origin/centre/midline
Proximal face is characterized by
three contact areas that are
defined by a Y mark or trilete
mark are centered on the
proximal pole.

12. The arms of the trilete mark may extend
to the equator, known as Laesurae
The equatorial contour is known as amb

13. The exterior surface of the spore in tetrahedral tetrad is
known as distal polar face
The dividing line between distal and proximal pole is known
as equator

14. Tetagonal Tetrads
They are often bean shaped
In tetragonal tetrads each spore is in
contact with two of its neighbouring
spores

15. The spores of vascular plants are characterized by openings
known as germinal aperture, which allows the germination of
prothallus (A small, flat, delicate structure produced by a
germinating spore)
Trilete spores have three Laesurae, which radiate at 1200 from
the proximal pole, the symmetry is therefore radial but
heteropolar

17. Monolete spores which have only one proximal Laesura (the
monolete mark) are bilateral and heteropolar
Morphology and terminology of monolete spores

18. Tetragonal tetrads have bilateral symmetry is therefore radial
but heteropolar

19. Wall Structure
The wall structure of both pollen and spore are multilayered but are
markedly different
Endospore
Inner exoospore
Outer exospore Perispore
Endospore rarely found in the fossil record
Exospore may be single or multilayered and is largely composed of
sporopollenin
Sporopollenin is chemically very stable, its composition is not exactly
known due to its high stability
The layer next to the exospore is perispore. This is completely composed
of sporopollenin

20. The layers may be uniform in thickness or variably thickened

21. A continuous equatorial thickening is known as cingulum

22. A continuous equatorial flange is known as zona

23. A spore with composite equatorial features is known as cingulizonate

24. Discontinuous equatorial features in radial areas are also developed in
some spores. When smooth they are called valvae while the ear-like
fluted structures are known as auriculae

25. Higher plants
Angiosperms
Gymnosperms

26. Pollen morphology
Pollens grains are distinguished by the
aspects of their morphology. i.e, size,
shape and surface sculpture
Size
Majority of the pollen grains has size
b/w 20 to 80 µm, with rare forms less
than 10 µm and more than 200 µm.
Shape
Prolate Subspheroidal
Oblate
Pentagonal Irregular Vesiculate

27. Aperture
The number and type of apertures
form the primary basis of the pollen
differentiation
Isodiametric apertures are called pores
Elongated apertures are called colpus
(plural colpi)
Pollen grain may have no aperture
(inaperturate), may have a single
aperture (monoporate/monoculpate,
may have two apertures
diporate/diculpate and may have three
apertures, triporate/triculpate

28. Sculpture
The ornamenting elements of the
pollen grain surface is known as
sculpture
Some twelve types of sculptures are
recognized
These include smooth, striated, pitted
etc
Applications of Pollens and Spores
Fossil pollens and spores are widely
used in correlation of terrestrial rocks.