Vascular Tissue System

Question 1

What is the role of the vascular tissue system?

Answer 1

The vascular tissue system transports carbohydrates, nutrients and water throughout the plant.

Question 2

Which meristem produces the vascular tissue system?

Answer 2

Vascular tissue is produced in the procambium.

Question 3

How is the vascular tissue system represented?

Answer 3

The vascular tissue system is represented by conducting fibres of xylem and phloem.

Question 4

What are vascular bundles?

Answer 4

Vascular bundles are made up of xylem and phloem.

- Xylem towards inside, phloem towards outside.

Question 5

Role of xylem?

Answer 5

Xylem: water + minerals.

• Support, sometimes storage
• main xylem cells are tracheary elements but some associated parenchyma and fibers also.

Question 6

Role of phloem?

Answer 6

Phloem: transport p/s products, signaling compounds (hormones) some misc bits.

Question 7

Where are vascular bundles?

Answer 7

Vascular bundles are embedded in the ground tissue, and connect plant body from root + stem to leaves.

Question 8

Where is the procambrium?

Answer 8

The procambium is in the middle of a vascular bundle, producing periclinal divisions.

Question 9

Protoxylem vs metaxylem?

Answer 9

Metaxylem is later and larger. Protoxylem is first formed and deteriorated.

Question 10

What are tracheary elements?

Answer 10

Tracheary elements = tracheids + vessel elements
- Both are lignified, conducting sclerenchyma with 2° cw that are dead at maturity, lack protoplasts at maturity: no nucleus or plasma membrane.

Question 11

Tracheids vs vessel elements?

Answer 11

Tracheids: long, narrow pits to allow water movement

• Narrow opening to give resistance to water flow
• Occur in groups
• Don’t let air bubbles through: have have holes, no cw
• Stronger
• 1mm

Vessel elements:

• Weaker
• Shorter, wider, with blunt ends
• pits and perforations at ends to give resistance to water flow
• 0.1mm
• Form continuous columns (vessels) up to 1.8m (white ash)
• Less resistance, quicker flow, generally more efficient

Question 12

How does xylem develop?

Answer 12

• Produced at procambium, becomes more differentiated up the plant.
• Protoxylem becomes damaged as plant elongates + matures into later (meta) xylem.

Question 13

What is the significance of types of thickening on tracheary elements?

Answer 13

• Type of thickening indicates how much stretching the plant can undergo.