Regeneration in Tissue Culture - Regeneration refers to the development of organised structures like roots, shoots, flower buds, somatic embryos (SEs), etc. from cultured cells/tissues; organogenesis is also used to describe these events. Root regeneration occurs quite frequently, but it is useful only in conjunction with shoots and embryo germination. Only shoot and SE regenerations give rise to complete plants, which is essential for applications of tissue culture technology in agriculture and horticulture. Often differentiation is used as synonym for regeneration. But differentiation describes the development of different cell types, e.g., vascular elements, etc., as well (cyto-differentiation). Therefore, it is more appropriate to use phrases like shoot differentiation, SE differentiation, etc. than using the term differentiation alone. Regeneration may occur either directly from the explant or may follow an intervening callus phase.