Organ systems in plants
Why don't plants have muscles? They don't need to move, and the primary function of a muscle is to move a body. 
A plant uses water and osmotic pressure to change the size of its cells. An example of this is a sunflower that draws water into the stalk and the head of the flower moves throughout the day. 
The transport of nutrients through a plant is accomplished by the vascular tissues. There are two types: Xylem and Phloem. 
(p73-75) Phloem conducts the sugars manufactured in the leaves. Xylem conducts the water and the minerals from the roots to the rest of the plant. Phloem is on the outside, and xylem is on the inside of a stalk.