1. Roots and Stems

2. Roots
Why are roots important? They may make up over half of the body of a plant
Roots: anchor the plant to the ground and absorb water and minerals the plant needs to grow

3. Parts of a root
Vascular cylinder: center of the root which contains the xylem and the phloem
-Surrounded by ground tissue & covered by dermal tissue
Most water is absorbed by the dermal tissue just above the root tip.
Root hairs: tiny projections on the dermal tissue. Root hairs find their way into spaces in the soil… greatly adding surface area for water absorption
Root cap: covers the root tip. Small cone of cells that protect the growing part of the root as it pushes through the soil

5. Parts of a root
Just behind the root cap is where most of the root’s growth occurs
Meristem: group of cells that are the source of new cells. Located just behind the root cap
Meristem cells are not specilized cells but as divide form specilized tissues
Apical meristems: areas of growth that lengthen tips of roots and stems
Lateral meristem: found all along woody roots & stems. Increase thickness.

8. Types of roots
Fibrous roots: fine branching roots which are mostly the same size
Tap roots: long thick vertical root with smaller branches

10. Water and mineral uptake
All plants require water and minerals
Mineral nutrients usually dissolved in water as ions
Nitrogen taken up as NO3- ions
Iron taken up as Fe2+ ions
Plants use energy to actively transport these ions into the roots
Increase concentration of ions causes water to move in by osmosis
Several essential minerals… Nitrogen, Magnesium, Iron

13. Roots