5B: Plant Vascular Tissues

Question 1

What is xylem tissue?

Answer 1

Tubes that transport water and minerals (potassium, nitrogen) in one direction FROM ROOTS TO LEAVES

Question 2

What are some features of a xylem tube?

Answer 2

• No end walls between cells
• Thick wall stiffened with lignin (hard, waterproof, rigid material)

Question 3

What is phloem tissue?

Answer 3

Tubes that transport sugars and other nutrients in both directions

Question 4

What are some features of a phloem tube?

Answer 4

• Cells have end walls with perforations

Question 5

What is a vascular bundle made of in a stem?

Answer 5

1. Sclerenchyma
2. Phloem
3. Xylem

Question 6

What does the cross section of a root look like?

Answer 6

X shape (xylem)
Phloem inside each part of X
This is called a stele.

Question 7

What does the cross section of a leaf look like?

Answer 7

Xylem and phloem along
Phloem is on top of xylem

Question 8

What do sclerenchyma fibres do?

Answer 8

Provided support for stem

Question 9

Name some plants organs.

Answer 9

Stem, roots, leaves, fruit, flowers

Question 10

What are the functions of the root system?

Answer 10

• Provide stability + support to plant
• Absorb water + minerals from soil

Question 11

What four processes are associated with water movement in plants, and explain briefly?

Answer 11

1. Adhesion (water sticking to walls of stem)
2. Cohesion (water molecules sticking to each other because of polarity)
3. Osmosis (movement of water pressure)
4. Transpiration (negative pressure)

Question 12

What happens as water evaporates out of the stomata?

Answer 12

More water gets pulled up by xylem vessels to replace lost water

Question 13

What happens if guard cells are turgid or flaccid?

Answer 13

Turgid: Stoma open (release water)
Flaccid: Stoma closed (retain water)

Question 14

What are the 3 purposes of transpiration?

Answer 14

• Regulates temperature
• Transports nutrients
• Maintain turgor pressure
• Provides water for photosynthesis

Question 15

How does hot temperature affect transpiration?

Answer 15

Hot temperatures will cause transpiration to increase, but very hot temperatures will cause transpiration to decrease.

Question 16

How do guard cells relate with photosynthesis?

Answer 16

When the plant needs carbon dioxide for photosynthesis, guard cells open stoma for gas exchange (and release oxygen)

Question 17

What is source and sink movement?

Answer 17

Sugars produced in sources (leaves) are delivered to sinks (growing parts) via thephloemvia translocation
Sinks: roots, young shoots, developing seeds

Question 18

What is transpiration?

Answer 18

Process of water movement through a plant and its evaporation from parts such as leaves, stems and flowers

Question 19

Why is glucose transported to roots?

Answer 19

Transported to sites of active growth where sugars are needed to support new tissue growth

Question 20

How does humidity affect transpiration?

Answer 20

As humidity increases, rate of transpiration decreases (easier for water to diffuse into dry air rather than saturated air)

Question 21

How does temperature affect transpiration?

Answer 21

As temperature increases, rate of transpiration increases (because kinetic energy of molecules also increase, causing osmosis and evaporation to occur faster)

Question 22

How does light intensity affect rate of transpiration?

Answer 22

As light intensity increases, rate of transpiration increases. Light causes stomata to open wider for greater entry of carbon dioxide for photosynthesis (greater diffusion of water)

Question 23

How can plants regulate water balance?

Answer 23

• Opening and closing of stomata
• Less stomata on the underside of a leaf
• Thick waxy cuticle that retains water