Biology Notes
Vascular Plants – Root Systems
Root Functions
1. Water Uptake:
• Roots take up water from the soil. (Xylem Tubes)
• This function is carried out by the young portions of the roots in the root-hair zone near the
growing root tip.
2. Mineral Uptake:
• Root hairs are responsible for absorbing mineral ions (calcium, magnesium, iron,
phosphorus, nitrogen etc.).
3. Conduction of water and minerals:
• Roots contain xylem, connected in an end-toend design to conduct water from the soil up
the plant and out through the leaves.
• xylem vessels allow soil water and minerals to be lifted up to the leaves.
• The evaporation of water from the leaves is the major pull of water through the xylem,
• Roots also contain phloem to conduct sugar made in the leaves (photosynthesis) to the
root tips.
4. Anchorage of plant:
• Roots can develop secondary xylem and/or can branch to provide steady anchorage for the
shoot system.
5. Storage of nutrients:
• The cortex of a root can store large amounts of starch, sugars, and minerals for long
periods of time.
• materials that remain in the trunk or root system all winter are returned to the shoot in the
spring sap flow. (Phloem Tubes)
Root Types
• During the late summer and fall, trees sense the changing day length signaling the
approach of winter and they send all nutrients down to the roots.
• The architecture of most root systems is generally some one of two different designs.
1. Fibrous Roots – characteristically seen in monocots (grass)
2. Tap roots – characteristically seen in dicots both herbaceous and woody (carrot)
Fibrous Root Systems
• Are the primary root of monocot plants (grass)
• Fibrous roots branch profusely radiating out into the soil to form a network of fine roots in a
large volume of soil particles.
• This design allows a plant to blow down easily but provides fabulous uprooting resistance.
• They also have to withstand grazing from animals
Tap Root System (Ex. Carrots)
• The primary root of the plant develops in length and girth with very little lateral branching.
• In trees this woody "post" provides excellent resistance to blowdown in wind storms.
• However a tap root provides little resistance to uprooting.
Vascular Plants – Root Systems
Root Functions
1. Water Uptake:
• Roots take up water from the soil. (Xylem Tubes)
• This function is carried out by the young portions of the roots in the root-hair zone near the
growing root tip.
2. Mineral Uptake:
• Root hairs are responsible for absorbing mineral ions (calcium, magnesium, iron,
phosphorus, nitrogen etc.).
3. Conduction of water and minerals:
• Roots contain xylem, connected in an end-toend design to conduct water from the soil up
the plant and out through the leaves.
• xylem vessels allow soil water and minerals to be lifted up to the leaves.
• The evaporation of water from the leaves is the major pull of water through the xylem,
• Roots also contain phloem to conduct sugar made in the leaves (photosynthesis) to the
root tips.
4. Anchorage of plant:
• Roots can develop secondary xylem and/or can branch to provide steady anchorage for the
shoot system.
5. Storage of nutrients:
• The cortex of a root can store large amounts of starch, sugars, and minerals for long
periods of time.
• materials that remain in the trunk or root system all winter are returned to the shoot in the
spring sap flow. (Phloem Tubes)
Root Types
• During the late summer and fall, trees sense the changing day length signaling the
approach of winter and they send all nutrients down to the roots.
• The architecture of most root systems is generally some one of two different designs.
1. Fibrous Roots – characteristically seen in monocots (grass)
2. Tap roots – characteristically seen in dicots both herbaceous and woody (carrot)
Fibrous Root Systems
• Are the primary root of monocot plants (grass)
• Fibrous roots branch profusely radiating out into the soil to form a network of fine roots in a
large volume of soil particles.
• This design allows a plant to blow down easily but provides fabulous uprooting resistance.
• They also have to withstand grazing from animals
Tap Root System (Ex. Carrots)
• The primary root of the plant develops in length and girth with very little lateral branching.
• In trees this woody "post" provides excellent resistance to blowdown in wind storms.
• However a tap root provides little resistance to uprooting.
