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Secondary Development in the Cortex of Isoetes

1982; University of Chicago Press; Volume: 143; Issue: 4 Linguagem: Inglês

10.1086/337319

1940-1205

Eric E. Karrfalt,

Marine and coastal plant biology

True secondary development, which arises in the more or less mature cortex and not from the circumstelar, primary meristem, is described in three species of Isoetes. The secondary cortex develops in relation to the process of furrow formation and to the shedding of layers of dead cortex. In the furrows, the secondary cortex is aligned in files tangential to the axis of the corm; on the surfaces from which old cortex is shed, it is usually aligned in radial files. In I. japonica, however, the secondary cortex at the surface from which dead cortex has been shed may consist of randomly oriented pairs of cells, which result from the division of numerous primary cortical cells. In I. japonica, typically elongate furrow cells also may develop in the secondary cortex in no relation to the furrows between the lobes. In I. nuttallii, secondary cortex reminiscent of an abscission layer occasionally develops through the region of attachment of individual roots.