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How did flowers and fruits assume their familiar appearance?

The Origin of the archetypal flower and fruit form in self-organized patterns in the ancestral germ plasm

SUMMARY

When your finger indents a balloon or a pillow, a symmetrical radial pattern immediately emerges on itssurface. A similar pattern emerges when you turn the sleeve of a coat inside out. A similar topological phenomenon is proposed as the developmental and evolutionary origin of the radial symmetry found invirtually all extant plant forms.

The precursor of the plant seed is the germ plasm, a single amoeboid cell, consisting of a protoplasm-filled membrane. During amoeboid cell locomotion, the membrane enters and re-enters the posterior of the cell. This action impresses a radial pattern on the membrane as it continues its passage through the center of the cell until progressing through to the exterior surface. This symmetrical pattern is presumed to persist in the subsequent subdivision of the germ plasm cell and to form the basis of the symmetrical patterning of the developing plant.

Figure 1. Flower morphogenesis from primordial germ plasm to flower and fruit. a. Germ plasm; b-d. Axial extension; e-g. Roots/shoot differentiation; h-m. Flower/fruit development.