Cell division in which there is first a simple cleavage of the nucleus without change in its structure (such as the formation of chromosomes), followed by the division of the cytoplasm; direct cell division; as opposed to mitosis. It is not the usual mode of division and is occur mainly in highly specialized cells which are incapable of long-continued multiplication, in transitory structures, and in those in early stages of degeneration. This type of cell division is found mainly in unicellular, prokaryotic plants e.g. cyanobacteria, bacteria, yeast, internodal cells of Chara zeylanica and Chara contraria, and endosperm cells of developing seed. etc.
Mitosis is the common method of nuclear division, followed by cytokinesis (cytoplasmic division). It usually occurs in vegetative or somatic cells therefore it is known as somatic division. It occurs in meristematic tissues - shoot, root tip. It results in the increase of size, shape, and volume of plant parts and causes growth. The pattern of mitosis is fundamentally the same in all cells. In this division, the mother cell produces two genetically identical daughter cells which resemble each other and also parent cell qualitatively and quantitatively. The separation of separate sister chromatids into two new cells with exactly the same number of chromosomes and half the amount of nuclear DNA is known as mitosis Therefore it is also called equational division Mitosis is also known as indirect division because it is an elaborate process involving a series of important changes in the nucleus as well as cytoplasm. In mitotic division not only the chromosomes are replicated but all necessary cytoplasm constituents and organelles are precisely divided between two daughter cells. In mitosis, there is no change in chromosome number. Mitosis is observed in all types of cells -haploid, diploid, or polyploid. If a parental cell has 1000 chromosomes, or even just 1 chromosome, the daughter cells have 1000 and 1 chromosome, respectively after mitosis.
