Introduction

In flowering plants, nutrition of the embryo is
an important and vital aspect of the life cycle.
 In angiosperms, it is accomplished by the
formation of a new structure, the endosperm,
produced by a unique event of double
fertilization.
Double Fertilization



Double fertilization occurs: One sperm nucleus (1n) fertilizes
the egg, producing a zygote (2n)  which becomes the plant
embryo inside the seed.
Another sperm nucleus fuses with the polar nuclei, resulting in
a triploid endosperm (3n).
Endosperm is a source of food for the young embryo.
Endosperm
History

Lampe & Mills (1933) were the first to report
the proliferation of immature endosperm tissue
of Maize, grown on medium containing extract
of potato.
 La Rue (1947) observed that in nature, in
maize , the pericarp ruptured & the endosperm
exhibited a white tissue mass.
Endosperm Culture

Sehgal (1974) cultured the immature
endosperm of Hordeum & Triticum.
 In organogenesis was successfully induced in
culture of immature endosperm of Oryza sativa
by Nakano et al. (1975).
Endosperm Culture

The age of endosperm at culture is critical for
its growth in vitro.
 In Maize, Wheat & Barley, endosperm tissue
younger than 8 or older than 12 days after
pollination did not grow in cultures.
 The endosperm of Cucumis can be grown only
when excised 4-7 days after pollination.
Media Requirement

The mature endosperm of parasitic taxa shows
optimal growth on a medium containing either
a cytokinin or a cytokinin & an auxin.
 In autotrophic members, casein hydrolysate or
yeast extract is also essential.

Endosperms of Santalum album, Croton
bonplandianum & Ricinus communis could
be grown on White’s medium containing 2,4D, kinetin & yeast extract.
 Organ formation has been demonstrated
mainly in parasitic species (Exocarpus,
Taxillus) and in some autotrophic species
(Croton, Santalum, Citrus)
Differentiation

In all parasitic members
- Differentiation of shoot buds or roots
without callusing.
 In autotrophic members
- Callus mass followed by differentiation of
shoot buds or roots.
Organogenesis in Culture

Organogenesis observed only in few species
such as Rice, Apple, Citrus, Santalum,
Croton, etc.
 In Ricinus communis, Zea mays & Cucumis
mature endosperm proliferation resulted in a
callus tissue of unlimited growth but
organogenesis did not occur.
Applications

Triploid plants can be raised through
endosperm culture.
 Wang & Chang (1978) produced triploid
plantlets from Citrus.
 Laxmi sita et al. (1980) developed triploid
plants of Santalum album .

Presently there are number of crop species
(banana, apple, beet, tea, mulberry) in which
triploids are in commercial use.
 Endosperm can be used as a nurse tissue for
raising hybrid embryos.