Developmental Anatomy of Cyperus esculentus (Yellow Nutsedge)

Abstract

Ontogenetic studies were made of the rhizome, tuber, and basal bulb of Cyperus esculentus (yellow nutsedge). Early in the growth of a rhizome, cells at the periphery of the vascular cylinder divide periclinally, forming radial rows of inner cortical cells. Tubers develop at the tips of rhizomes that originate from tubers and basal bulbs. Early in development of a tuber, a primary thickening meristem (PTM) is established at the bases of young leaf primordia, which is responsible for the early establishment of the cortex. At lower levels of the developing tuber, the PTM becomes primarily a root-producing meristem that may be close to or somewhat separated from the central cylinder that consists of individual but interconnected vascular bundles. Increases in size of the cortical and central parenchymatous regions in the tuber are primarily the result of the function of a ground meristem and cell enlargement. At maturity, the parenchymatous cells are packed with starch grains. Basal bulbs originate from rhizomes that possess more complex vascular cylinders than those that give rise to tubers. The basal bulb is a greatly shortened axis with a complex set of vascular bundles that is basically leaf traces. A PTM within the basal bulb arises near the shoot apex. The meristem extends down in cup-shaped fashion and gives rise to derivatives that form roots, horizontally encircling procambial strands, and parenchymatous sectors. Procambial strands vascularize rhizome primordia that are initiated at the surface of the basal bulb.