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Types of endosperm
1. PRESENTATION ON โTYPES OF ENDOSPERMโ
GUIDED BY- PRESENTED BY-
DR. NAMITA NATH RASHMI H. RAHMAN
M.SC 2ND
SEM
DEPT OF BOTANY
ROLL NO 3
GAUHATI UNIVERSITY
2.
3. INTRODUCTION
Endosperm is a nutritive tissue stored in the
seed for the embryo and it is formed by the
fusion of one male gamete with the polar
nuclei.
-Endosperm plays a main role in the diet of
human beings.
-Endosperm is found in all angiosperms except
few families like
Orchidaceae,Podostemonaceae and
Trapaceae.
-The seeds without endosperm: Non-
endospermous seeds or exalbuminous seed.
-The seed containing the endosperm:
Endospermous or albuminous seed.
5. TYPES OF ENDOSPERM
-Endosperm is classified into 3 types by
Schnarf(1929) on the basis of their mode of
development:
1.Nuclear endosperm
2.Cellular endosperm
3.Helobial endosperm
Fig: A-Nuclear ,B-Helobial C- Cellular
endosperm
6. NUCLEAR ENDOSPERM
In this type of endosperm, the division of the
primary endosperm nucleus and its further
divisions are not followed by wall formation.
Examples. Limnanthes, Oxyspora
Fig: Neuclear endosperm in Limnanthes
๏ In some plants, the nuclear endosperm
becomes cellular at a later stage.
7. ๏ Ex. Acalypha, Phaseolus.
Fig: A-E; stages in the development of
Neuclear type of endosperm
CELLULARIZATION OF NUCLEAR ENDOSPERM
๏ The cellularization of nuclear endosperm
shows variations.
๏ In Acalypha,the endosperm becomes
cellular completely.
In Grevillea, the endosperm is cellular in the
micropylar region and nuclear in the chalazal
8. end. The nuclear chalazal end develops into a
vermiform appendix (Kausik,1941
Fig: Endosperm formation in Acalypha
๏ In coconut,the endosperm is nuclear type.
Later on it becomes cellular.The PEN
undergoes several free nuclear divisions.
๏ The endosperm in coconut is partly solid
and partly liquid.
9. Fig: Endosperm formation in Cocos nucifera
CELLULAR ENDOSPERM
๏ The division of the PEN and its further
divisions are followed by immediate wall
formation and the free nuclear stage is
completely absent.
๏ It is common in dicots.
๏ Haustoria are common.
10. Fig: Development of cellular endosperm in
Drimys winteri
Haustoria in Cellular Endosperm
๏The haustoria may arise at the
micropylar end or at the chalazal
end or both.
๏In Impatiens , micropylar haustorium
is produced.
๏In Nemophila both micropylar and
chalazal haustoria are found.
12. HELOBIAL ENDOSPERM
๏It is intermediate in structure.
๏Development is intermediate
between nuclear and cellular types.
It is more common in monocots.
Davis(1966) reported the presence of
helobial endosperm in 14 monocot
families
Fig: Development of helobial type of
endosperm in Eremurus
15. REFERENCE:
1. THE EMBRYOLOGY OF
ANGIOSPERMS, 5TH EDITION, S S
BHOJWANI & S P BHATNAGAR
2. DEVELOPMENTAL BOTANY AND
EXPERIMENTAL EMBRYOLOGY,
ANNIE KUMMARESAN
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