Variation in shoot organization of Cynodon dactylon: is it the grass with an opposite phyllotaxy?

Abstract

Although grasses basically have a distichous phyllotaxy, the vegetative shoots of Cynodon dactylon seem to show two types of phyllotaxy, including opposite phyllotaxy. These phyllotaxies, however, may be formed by internodal growth after initiation of leaf primordia. To determine the initial phyllotaxy of C. dactylon, we observed the development and anatomy of the shoot apices of vertical and creeping vegetative shoots. The former seem to have an opposite phyllotaxy and the latter have a triserial phyllotaxy. In both vertical and creeping shoots, the initiation pattern of the leaf primordia was clearly distichous and the leaf primordia on shoot apices were more concentrated than those of other grasses. Therefore, apparent phyllotaxies, including opposite phyllotaxy, can be derived in C. dactylon from the regulation of internodal growth after concentrated initiation of distichous leaf primordia.