Plant Physiology - Lecture Notes - O. M. Tarnopilska 2019

7. Plant Growth and Development
7.4 Shoot Morphogenesis

The main parts of a SHOOT — the stem, leaves, and flowers — originate in the shoot apical meristem, which is derived from the embryonic tissue at the distal end of the embryo. The apex (growing cone) of a vegetative shoot in a flowering plant consists of meristematic Cells that can be divided into several zones based on their size, division rate and direction, and metabolic features.

The tunica (or mantle) consists of one, two, or more layers of cells covering the apex externally. The epidermis develops from the outermost layer of the tunica. All other cells located beneath the tunica make up the corpus, which comprises the central, peripheral, and pith meristem zones.

The peripheral zone (initial ring) is composed of small, actively dividing meristematic cells. The cells of this zone form the primordia of lateral shoot Organs: leaves and buds.

The Cells of the central zone function as initials. The cells of the pith zone divide and give rise to the longitudinal Cell rows of the primary cortex and the pith of the stem. The boundaries between these zones are rather conventional.



Last update: 07/08/2026

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