2. 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.

3. 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.

4. Endosperm

5. 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.

6. 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).

7. 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.

8. 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.

9.  Endosperms of Santalum album, Croton bonplandianum & Ricinus communis could be grown on White’s medium containing 2,4- D, kinetin & yeast extract.  Organ formation has been demonstrated mainly in parasitic species (Exocarpus, Taxillus) and in some autotrophic species (Croton, Santalum, Citrus)

10. 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.

11. 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.

12. 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.

13.  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.