Each specialized cell type in an organism expresses a subset of all the genes that constitute the genome of that specific species. Each type of cell is defined by its pattern of regulated gene expression. Cell differentiation is thus, simply a transition of a cell from one type of cell to another and involves a switch from one pattern of gene.
Embryonic differentiation is the process of development during which embryonic cells specialize and diverse tissue structures arise. Animals are made up of many different cell types, each with specific functions in the body. However, during early embryonic development, the embryo does not yet possess these varied cells; this is where embryonic differentiation comes into play.
In multi-celled organism, each task of life is carried out by different types of cells say nerve cell, cardiac cell, muscle cell, epithelial cells all differ in their appearance and function, but originated from the same parental cell, the zygote. These specialized cells are formed by a process called differentiation.
According to Thiel et al. (2008), plant hormones are largely involved in influencing the cellular differentiation in plant tissue culture. They are organic compounds that regulate the growth and development of target cells. There are five main types of plant hormones which are the auxin, cytokinin, gibberellins, abscisic acid and ethylene.
In other cases the strands undergo differentiation into an outer layer with blackened, hardened cell-walls and a core of ordinary hyphae, and are then termed rhizomorphs (Armillaria mellea), capable not only of extending the fungus in the soil, like roots, but also of lying dormant, protected by the outer casing.
Following his retirement he published Morphogenesis in Plants: A Contemporary Study (1968); and the collections Essays on Form in Plants (1968) and Cellular Differentiation in Plants and Other Essays (1969). Professor Wardlaw was also active outside his own department, becoming dean of the Faculty of Science in 1950 and 1951, and pro-vice-chancellor between 1953-1957.