How to Build a Plant
• Did you know that a plant embryo has a heart stage?
• As in animals, a fully functional plant is built from a single cell. After the first set of divisions, the 8 cells (octant) are already distinguished into upper and lower halves that will become the shoot and root.
• Next, each cell divides tangential to the surface to separate into outer and inner layers (globular stage). The cells near the base elongate, while those near the top divide horizontally to form a triangle, and then a heart shape. The furrow in the heart deepens to form a torpedo, which eventually unfurls to form the first leaves (cotyledons) of the seedling.
• The evolution of multicellular organisms occurred many times and independently, in plants, animals, algae and fungi. The switch from a solitary existence to a community of cells happened long ago (over 500 million years). The challenges to building this community may sound familiar: how to control its growth, division of labor, mutual cooperation and resolution of conflict 🙂
Image Source: http://www.plantphysiol.org/content/139/2/701/F3.full