Endosperm is a rich repository of carbohydrates, proteins, fats and oils with accessory substances like enzymes, vitamins and growth regulators. The more important contribution of endosperm is in the nutrition of embryo during its early stage of development. Generally, the embryo grows only when the endosperm develops properly. If the endosperm aborts, the growth of the embryo is also affected. However, if the young embryo is excised and transplanted in a culture medium containing the necessary growth substances, the embryo can be made to attain maturity. Coconut milk (liquid endosperm of coconut) has been commonly used as a culture medium.
The earliest reference on endosperm culture available to us is that of Lampe and Mills (1933). They grew young corn endosperm on a medium containing an extract of potato and observed proliferation of endosperm layers adjacent to the embryo.
Larue (1949) was able to raise, for the first time, con¬tinuously growing tissue from the immature endosperm corn.
Subsequently, tissue cultures were made from the immature endosperm of Asimina, Lolium, Cucumis satiuus, etc. Rangaswamy and Rao (1963) demonstrated that it is possible to induce divisions in mature endosperm of Santa lam album and raise continuously growing tissues from them.
The endosperm tissue in nature lacks differentiation; it does not show vascular elements. However, in cultures the differentiation of tracheidal elements in this tissue is quite common.
The use of endosperm tissue in raising other plant cultures 'in vitro' has proved to be of immense utility. Overbeek showed that immature embryos of Datura, which would otherwise abort, could be cultured outside the ovule by the addition of liquid endosperm of coconut to the nutrient medium. Much work has been done on this line.
