Transport in Plants - Xylem

Question 1

What does xylem tissue do?

Answer 1

Transports water and mineral ions in solution up the plant from the roots to the leaves

Question 2

What does phloem tissue do?

Answer 2

Transports organic substances both up and down the plants

Question 3

What are xylem vessels?

Answer 3

Part of the xylem tissue that transports the water and ions

Question 4

What is the structure of xylem vessels?

Answer 4

Very long, tube-like structures formed from dead cells joined end to end. There are no end walls in these cells, making an uninterrupted tube that allows water to pass up the middle

Question 5

What helps water move up plants from roots to leaves?

Answer 5

Cohesion and tension

Question 6

How do cohesion and tension help water move up a plant?

Answer 6

Water evaporates from the leaves at the top of the xylem - transpiration. This creates tension, which pulls more water into the leaf. Water molecules are cohesive so when some are pulled into the leaf other follow. This means the whole column of water in the xylem, from the leaves to the roots, moves upwards. water enters the stem through the root

Question 7

What is transpiration?

Answer 7

Evaporation of water from a plants surface

Question 8

Explain transpiration

Answer 8

Water evaporates from the moist cell walls and accumulates in the spaces between cells in the leaf. When the stomata open, it moves out the leaf down a conc gradient

Question 9

What 4 factors affect transpiration rate?

Answer 9

1. Light
2. Temperature
3. Humidity
4. Wind

Question 10

How does light affect transpiration rate?

Answer 10

Lighter it is, faster transpiration rate - stomata open when its light to let in CO2 for photosynthesis. When it’s dark stomata usually close, so little transpiration

Question 11

How does temperature affect transpiration rate?

Answer 11

Higher the temp, faster transpiration rate - warmer water molecules have more energy’s the evaporate from cells in the leaf faster, this increases conc gradient between inside and outside of leaf, so transpiration increases

Question 12

How does humidity affect transpiration rate?

Answer 12

Lower the humidity, faster transpiration rate - if air around plant is dry, the conc gradient between the leaf and air is increases, increasing transpiration

Question 13

How does wind affect transpiration rate?

Answer 13

The windier it is, faster transpiration rate - lots of air movement blows away water molecules from around the stomata, this increases conc gradient, increasing transpiration rate