Plant Transplantaion?

Question

Why can you cut your grass often and still have it grow while if you top a tree, it sops growing in height? How does this relate to plant anatomy?

Answer 1

It is to do with the location of the "meristems" - the parts of the cell which contain the dividing cells, and which actually do the "growing".

Trees have "apical meristems" - the tips of the branches and twigs; if you cut off that part, there is no bit with dividing cells to grow any more. They also have "lateral meristems", patches of cells on the sides of the branches which can start growing; normally these are inhibited by hormones secreted by the nearest apical meristem, but if that meristem moves far enough away, or if it is removed, then the lateral meristem can start growing. This is why trees can form side-branches, and is why pruning a bush or tree will make it more bushy.

Grasses, OTOH, have a basal meristem: their growing cells are at the *base* of the leaf. If you chop-off the tip of the leaf, the base just keeps on growing.