The document discusses the male gametophyte (pollen grain) in angiosperms. It describes the pollen wall features including the inner pectocellulosic layer and outer sporopollenin layer. It also discusses microsporogenesis where a diploid microspore mother cell undergoes meiosis to form four haploid microspores that each become a pollen grain. Additionally, it summarizes the scope of palynology as the study of pollen grains and spores, including their resistant sporopollenin exine layer and preparation through germination and double fertilization within the ovule.

1. Male Gametophyte -Morphology
Presented By-sapana prajapati
M.sc (sem-2)BotanyM.sc (sem-2)Botany
Roll No-202
CBO-404
Department of life sciences,
H.N.G.U.,PATAN

2. Content
• Introduction
• Pollen Wall features
• Scope of palynology
• Preparation of pollen grains

3. Introduction
• In the sexual process the pollen grain
produce male gametes,and egg secondary
nucleus are formed in the embryo sac.
• One male gamete fuses with the egg,and the
other with the secondary nucleus or the two
polars,resulting in triple fusion.

4. Cont…
• These processes are referred to as “double
fertilization,”a unique characteristic of the
angiosperms.
• The zygote usually develops into a bipolar
structure,the embryo,a product of tripal
fusion produces the endosperm.

5. Cont…
• Microsporogenesis:-Diploid cell=microspore
mother cell= = >Meiosis = = > 4 spores at the
end of process (i.e.,tetrad).Each microspore
becomes the pollen grain=malebecomes the pollen grain=male
gametophyte.

6. Cont…

7. Pollen wall features
• Pollen wall formation occurs in two phases.
• In the first phase,the wall material is
contributed to by the cytoplasm of the spore
alone which occurs during the tetrad stage.alone which occurs during the tetrad stage.
• In the secondary phase,which occurs the relese
of the microspores.

8. Cont
…
• The wall of a pollen grain is Made up of the
two layers the inner pectocellulosic
layer,which is degraded during acetolysis.
• The outer layer,exine,which is acetolysis and
biological degradation.
• The exine is composed of sporopollenin.

10. Scope of palynology
• Palynology is the science of pollen grains and
spores.
• The pollen grain:-Immature male• The pollen grain:-Immature male
gametophyte of seed plants.protected from
desiccation and mechanical damage by a wall
composed of two layers: intine and exine.

11. Cont…
• Exine:- outer most,resistant to
desiccation,decay and other mechanical
damage,with sporopollenin.
• Sporopollenin :- Polymer of carotenoids,fatty
acids,phenolics and phenylpropanoid.
• Intine :-inner layer,composed of the cellulose
and pectin.

12. Preparation of pollen grains
• Male gametophytes are contained within
pollen grains produced by the
microsporangia of anther.
• A pollen grain that has lanted on a stigma
germinates and the pollen tube of the male
gametophytes grows down to the ovary.

13. Cont…
• The ovule is entered by a pore called the
micropyle.
• Double fertilization occurs when the pollen• Double fertilization occurs when the pollen
tube discharges two sperm into the female
gametophyte with in an ovule.

14. Cont…
• One sperm fertilization the egg (now a zygote
2n) while the other combines with two nuclei
in the central cell of the female gametophyte
and intiates development of food-steringand intiates development of food-stering
endosperm (3n).

15. Cont…

16. Cont…
• Reference :-Taxonomy of angiosperm by
• B P Pandey
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