Morphology and anatomy of rice roots with special reference to coordination in organo- and histogenesis

Abstract

Rice belongs to monocotyledon which is characterized by having a so-called fibrous root system. Such root system is built up with seminal and nodal roots with numerous lateral roots. Morphology and anatomy of rice roots which is fundamentally the same as other cereal crops, has been relatively well-described. Rice roots, however, have their own characteristics including well-developed air space in the matured cortex. In addition, many examples of coordination were shown in root organo-and histogenesis as well as root function. Morphometric analysis on anatomy of matured rice roots including vascularization suggests that differentiation and maturation of each tissue in roots proceed quite integratedly. Because vascular system is quite important with reference to root function, many studies have been done. However, following aspects of vascularization have rarely been examined; (a) connections between vascular systems of stem and nodal roots, (b) changing patterns of vascular system along the root axes, (c) connections between vascular systems of the parental roots and their lateral roots and (d) connections among different kinds of vascular elements in the same roots. Morphology and anatomy with reference to coordination in organo-and histogenesis should be further studied in order to understand both structure and function of rice roots.