The Physiology of Root Growth

Abstract

The elongation of the growing root is the outcome of cell division at the root apices giving rise to cells which Immediately become committed to expansion and differentiation. The root apex, has arranged in sequence all stages of development from meristem initial to mature tissue cell. Delineation of the separate tissues to give the distinctive tissue pattern of the organ occurs simultaneously. The root is a good experimental object for the study of growth and differentiation in a multicellular plant. In the study of root growth and development we see not only steady-states of metabolism as seen in the maintenance of merlstematic activity at the apex, but changing patterns of metabolism as seen in differentiation and the breakdown of metabolic regulation as seen in senescence. The metabolism of each cell comes not only under the influence of its own nucleus, but is profoundly influenced by a complex of external factors and by intrinsic factors (hormonal and nutritive) coming from other cells in the root and beyond that from the shoot system.