B2.2.5 - Transpiration Stream

Question 1

Define transpiration

Answer 1

Loss of water from leaves/stems of plant (due to gaseous exchange)

Question 2

Define transpiration stream

Answer 2

Constant flow of water from roots (xylem brings into leaves)

Question 3

What does the xylem do?

Answer 3

Water travels up jt from the roots to the leaves of plants
This replaces water lost from transpiration

Question 4

Describe some adaptations of xylem

Answer 4

Lignin deposited: kills cells and strengthens plants, withstand pressure
- cells hollow out, join up forming a tube for water/mineral ions

Question 5

Describe some adaptations of guard cells

Answer 5

Kidney shaped
Thin outer walls, thick inner walls
Most at bottom of leaf, minimised water loss

Question 6

How is water lost from leaves?

Answer 6

1) When stomata is open, water evaporates from cells
2) Creates concentration gradient, allows diffusion for water vapour out lead

Question 7

Describe the cuticle

Answer 7

A waxy waterproof layer on surfaces of leaves, prevents extra water loss