Plant structure, growth, and development help?

I can tell you this, its all about the mitosis. Cell elongation, separation, division thing. In order for the plant to grow it needs cell elongation (dividing cells). usually this will happen in the meristem and roots. When a cell undergoes mitosis the microtubules start to separate/ divide. they provide structure to the cell membrane. try to look up mitosis and the movement of the cell. good luck.