morfogenética

Geometry of Integration and Differentiation in Plant Stem

This Section through the stem of a geranium reveals the close-packed bundles of differentiated vessels and specialized cells. The geometrical arrangement and close-packed integration produces a complex structure, strong but flexible, and capable of differential movement. All the cells have a structural role in addition to other functions, and structural capacity emerges from their interaction. The large pale tubes in the centre are xylem vessels that transport water and nutrients up from the root. These vessels are reinforced by spiral helices of lignin; the geometry of the spiral helix allows elongation for growth without loss of strength. The five bundles of pale green vessels are phloem cells, part of the vascular system for the distribution of carbohydrates and hormones, and the smaller purple cells on the perimeter are parenchyma cells, which is how the plant achieves movements such as bending towards the light or around an obstacle. The arrangement of cells of different sizes and orientations constrains the movement in the direction that is needed. The stem is enclosed by the epidermis, a double layer of cells, some of which are specialized, with hairs or oil glands.
(fuente:Emergence: Morphogenetic Design Strategies (Architectural Design) by Michael Hensel, Achim Menges, and Michael Weinstock )