Plant Growth

Growth is one of the defining features of every living organism, and in plants it shows two related aspects. The quantitative aspect is a measurable increase in length, breadth, volume, body mass, dry weight or number of cells -- it is the visible end-result of successful metabolism. The qualitative aspect concerns a change in the nature of growth: development is the ordered, sequential change an organ undergoes, while differentiation is the process by which cells acquire a more complex, specialised state. Taken together, growth can be defined as a permanent and irreversible increase in the bulk of an organism, usually accompanied by a change in form.

Unlike most animals, vascular (multicellular) plants show open, indeterminate growth -- growth continues throughout the life of the plant rather than stopping once a fixed adult size is reached. This continuous production of new cells is not spread evenly over the plant body; it is confined to specialised regions called meristems, where cells divide constantly. Meristems are of three types based on location: apical, intercalary and lateral.