Reproductive biology of angiosperms

1. Embryogenesis
Submi�ed to :-
Dr. Harwinder kaur
Submi�ed by :-
Deepika rani
UID :- 180606009

2. Contents:-
Common terms
Proembryo
Types of embryogeny
General pa�ern of development
of: --Monocot embryo
-- Dicot embryo

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Embryogeny :-
The process during which unicellular fer�lized makes a
progressive transi�on towards embryo.
Embryo:-
a diploid cell resul�ng from the fusion of two
haploid gametes; a fer�lized ovum
Zygote :-
Early developmental stage of a mul�cellular
organism.

4. Proembryo :-
_Star�ng from the 2- celled stage un�l the
ini�a�on of organs the embryo is commonly
called proembryo

5. Types of embryogeny :-
Maheshwari in 1950 , recognized five main
types of embryogeny .
These are :-
1) Onagrad type
2) Asterad type
3) Solanad type
4) Chenopdiad type
5) Caryophyllad type
The classifica�on was based on the plane of
division of the apical cell in 2 celled
proembryo and contribu�on of apical cell and
basal cell in embryo forma�on .

6. Cont....
These five types of embryogeny refer to those
plants where first division of the zygote is
transverse.
Later Johansen recognized sixth type of
embryogeny ,called Piperad type which
includes those plants where first division of the
zygote is ver�cal .

8. Cont....
A.The apical cell of 2 celled proembryo divides
longitudionally .
1) Basal cell plays minor or no role in further development -
Onagrad type .
Examples - Onagraceae, Brassicaceae, Pedaliaceae .
2) Basal cell and apical cell both con�bute to further
development - Asterad type
Examples - Asteraceae , Vitaceae , Violaceae family .
B. The apical cell of 2-celled proembryo divides transversely .
I - The basal cell plays only minor role or none in subsequent
development .
3) Basal cell forms suspensor - Solanad type .
Examples - Solanaceae, Theaceae, Linaceae families .
4 ) Basal cell undergoes no further division and suspensor if
formed is always derived from apical cell - Caryophyllad type .
Examples- Caryophyllaceae , Crassulaceae families .
II - 5)Basal cell and apical cell both contribute to further
development -Chenopodiad type
Examples- Chenopodiaceae , Boraginaceae .

9. General pa�ern of development
of dicot embryo:-
• Development of embryo in
Ceratocephalus falcatus
completely illustrates
development of dicot embryo .
• It was explained by Bhandari
and Asnani in 1968 .
• It have Onagrad type of
embryogeny .

10. • Embryogenesis in
Ceratocephalus falcatus .

11. Cont....

12. General pa�ern of development of
monocot embryo :-
• Development of embryo in
Najas lacerata describes
complete development of
monocot embryo .
• Described by Swamy and
Lakshmanan in 1962.

13. • Embryo development in Najas
lacerata:-

14. Cont....

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