Roots and shoots. I wrote a couple of entries about seeds recently. The last one (30th. October) looked at the life cycle of a seed up to the point of germination. One of my flatmates is growing this avocado plant in the kitchen and it provides a good illustration of what comes next.
 What we can't see here is the first growth that takes place which is the emergence of the radicle (the embryonic root covered in fine root hairs to absorb water and minerals). The radicle is positively geotrophic i.e. it grows down. This is the consequence of cell division of the epicotyl which is at the base of the radicle and has the effect of anchoring the plant.
 Then comes the plumule (the embrionic shoot). It's negatively geotrophic; in other words it grows up! This results from the enlargement of the hypocotyl close to the base of the plumule.
  Thus the seed becomes a seedling and eventually a mature plant.