The entire genomic DNA cannot express at a time. In this process only particular type of gene is expressed at a time, specifically leading to the production of a particular gene product which is in turn specific for a plant organ or tissue. These specific genes are responsible for the special characteristics like smell, taste, color, texture, etc., of the different pant organs. Furthermore plant cells have the capacity to generate into a complete plant, this property of plant cells is called Totipotency. Two terms define the growth of plants, i.e. Proliferation & Differentiation. Proliferation means the division of the cells, without any alteration to the cells genome, where as differentiation refers to the conversion of a plant cell to a particular type according to the organ of plant. For example the same plant cell can differentiate into a leaf cell which is green in color or a flower cell which has certain color, odor & texture or a fruit cell which has a definite characteristic which is different from other plant organs. This property of cells to form into different organs, which is happening at the gene level, may be defined as differentiation.
Two Scientists namely, Theodor Schwann and M.I.Schlieden in 1838, studied reproduction in plants and found Totipotency in plant cells. Apart from Totipotency, several terms are used to explain the properties of plant cells, i.e. the plant cells capacity to regenerate into organs or complete plants may be defined as regeneration, plasticity of the plant cells defines the morphological & metabolic changes happening in plant cells due to environmental conditions, and the cells which carry artificially introduced genes into them are called as transformed cells.