Pineapple Stem And Slip

The pineapple stem is club-shaped, with a length of 25-50 cm and a width of 2-5 cm at the base and 5-8 cm at the top. Its aerial part is straight and erect, while the shape of the earthed part depends on the material used for planting. It is markedly curved when coming from a slip, as the stems of these propagules are comma-shaped, less curved when coming from a stem shoot and erect when coming from a crown. Nodes can be visualized by the leaf scars left after stripping the leaves from the stem. Internodes are short (1-10 mm according to their position), so the whole rosette appears dense and compact. Flattened shoot buds, 3-5 mm high and about 5 mm wide, occur in the leaf axils. In the central portion of the stem, they are larger because of an increase in the size of their prophyll (the first leaf of the shoot, which encloses it). A striking feature of the pineapple stem is the presence of adventi

© CAB International 2003. The Pineapple: Botany, Production and Uses (eds D.P. Bartholomew, R.E. Paull and K.G. Rohrbach)

Pineapple Slips And Crown Images

Crown

Axillary crownlets

Slip

Stem shoot

Ground shoot or sucker

Fig. 2.1. Main morphological structures of the pineapple plant.

Crown

Axillary crownlets

Slip

Stem shoot

Ground shoot or sucker

Fig. 2.1. Main morphological structures of the pineapple plant.

tious roots breaking through the epidermis, and growing flattened and distorted, tightly wound around the stem, between the leaves. Their older portion is suberized. These aerial roots rarely produce laterals. They are elongated from a few millimetres in the subapical region to 10 cm or more near the stem base. Thus, the underground portion of the stem is covered with a tuft of adventitious fibrous roots.

The stem (Fig. 2.2) constitutes a central cylinder, or stele, and a cortex, separated by a thin layer of vascular bundles produced by the dome-shaped apical meristem. The dense network of vascular tissue separating cortex and stele consists chiefly of xylem, with very little phloem. In this tissue, areas of non-vascular tissue, or leaf gaps, are disposed at intervals, allowing leaf-trace bundles to pass from the cortex into the stele. This vascular cylinder is thicker and suberized at the stem base. On the cortical side, a narrow layer of long, thin-walled cells bound it. Vascular bundles are very numerous throughout the stem but less so in the cortex than in the stele. The latter is mainly constituted of a compact parenchyma with abundant starch. It contains large cells with raphides of calcium oxalate crystals. The cortex is composed of a parenchymatous tissue, crossed by the isolated vascular bundles going to the leaves, of the adventitious roots originating at the boundary with the central cylinder and of circumferential small bands of vascular tissue lying just above the leaf attachment to the stem. The inner parenchyma of this cortex is also rich in starch and contains raphide cells. Limiting the stem externally is the epidermis, with peltate trichomes in the nodal regions.

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Responses

  • geraldino
    What is a pineapple slip?
    7 months ago
  • Laurence Shaw
    What is pineapple stem?
    4 months ago

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