The roots of a plant form a branched network responsible for the absorption of water and minerals from the soil

• Fibrous roots are thin and very spread out to improve absorption, but are not very effective at anchorage (more suitable for smaller plants)
  

• Tap roots possess a deeply penetrating main root with many lateral branches (can access deeper soil layers and provides better anchorage)
  

Roots possess three main tissue layers that are organised to optimise the absorption of water and dissolved solutes

• The outer epidermis is where water and minerals enter the roots and may have protrusions (root hairs) to maximise surface area
  

• The middle layer (cortex) facilitates water movement between loosely packed cells and also functions as a storage site for starch
  

• The innermost layer is the vascular tissue (phloem and xylem), which allows for the transport of materials to other parts of the plant
  

Root Cross-Section

Root Anatomy

The tissues in a root are specifically distributed to maximise the absorption and transport of water and minerals

• The epidermis may have protrusions called root hairs to increase the available surface area for material absorption
  

• The cells in the cortex are loosely packed to enable the movement of water between the intercellular spaces
  

• The vascular bundle is surrounded by cells with a modified cell wall (casparian strip) that is impermeable to water 
  

  • This forces water to move into the cells to access the vascular bundle, facilitating greater control of water movement
    

Root Tissue Distribution