Xylem

• Xylem moves water and minerals through a network of tubes. The tubes are actually dead cells, but the walls remain. These walls not only form tubes, but also give the plant structure. When you forget to water your plant and it wilts, it is because the xylem tubes are empty. Due to its high surface tension, water is able to flow upward through the xylem.
  
  

Phloem

• Phloem transports sugar, amino acids and other nutrients through the plant. The plant's phloem moves these molecules from where they are produced to where they can be stored as energy reserves. Unlike the dead cells of xylem, phloem is living tissue.
  
  

Roots, Stems and Leaves

• Besides being an anchor for the plant, roots take in water and nutrients from the soil and also act as a reservoir for energy. Stems act as the plant's circulatory system, moving water and nutrients from one place in the plant to another. Leaves make food for the plant through photosynthesis, draw in carbon dioxide and release oxygen.
  
  

Putting It Together

• When the roots pull in water and minerals from the soil, the xylem transports them upward to the stem and eventually to the leaves. The leaves photosynthesize to make sugars, amino acids and other nutrients for the plant. The phloem then carries these molecules to the flowers, back down the stem and to the roots. The roots then store these molecules for the plant to survive the winter or harsh weather.