Vascular Differentiation in the Shoot Apex of Matteuccia struthiopteris

来自 EBSCO

阅读量：

作者：

展开

摘要：

Initial vascular differentiation is generally considered to occur in procambium. In ferns, however, a provascular tissue immediately subjacent to the promeristem has been suggested as an initial stage within which the procambium is subsequently formed. In contrast to this interpretation, a zonation concept applied in ferns recognizes a promeristem consisting of several layers of cells in which no differentiation takes place. This study demonstrates that the shoot apex of Matteuccia struthiopteris has one cell layer of promeristem. Immediately subjacent to the promeristem is the provascular tissue surrounding a central group of pith mother cells. The developmental continuity between the provascular tissue and the mature vascular tissue, and between the pith mother cells and the pith, through transitional stages, indicates that the initial differentiation of vascular tissue and pith takes place in this prestelar tissue. The continuity of vascular differentiation in the area confronting young leaves or incipient leaf positions is interrupted by the formation of leaf gap initials. Developing leaves thus begin to exert influence on the vascular system at the prestelar stage. Small protoxylem elements with helical cell wall thickening, and distinctive protophloem elements are present in the leaf traces, but end abruptly near the junction regions of leaf traces to the meristele.

展开

关键词：

Initial vascular differentiation, provascular tissue, pith mother cells, shoot apex, Matteuccia struthiopteris

DOI：

10.1006/anbo.1994.1157

被引量：