Plant Homeostasis - Halophytes

Question 1

Define what a halophyte is.

Answer 1

A plant adapted to live in environments with a high soil salinity such as salt marches and the mud flats of estuaries.

Question 2

Outline the 4 steps of the uptake of water in salty environments.

Answer 2

1. Concentration of salt is higher in soil than in root cells.
2. Therefore water no longer moves into he cell by osmosis.
3. Plants die from a lack of water.
4. Build up of salt in cells can interfere with the production of hormones and enzymes and metabolism and cell function.

Question 3

List 4 adaptations halophytes experience.

Answer 3

1. Filtration.
2. Vacoules in root cells.
3. Accumulation of salt.
4. Suuculence.

Question 4

Describe filtration as an adaptation found in halophytes.

Answer 4

The roots regulate the amount of salt entering the plant. Root cells that are impermeable to salt from entering the plant.

Question 5

Describe vacuoles in root cells as an adaptation found in halophytes.

Answer 5

Store salt and increase the salt concentration of roots so it is greater than that in the soil. This allows water movement into the roots.

Question 6

Describe the accumulation of salt as an adaptation found in halophytes.

Answer 6

Accumulate salt in older leaves, salt bladders or bark which can discard bladders. This reduces the amount of salt in the plant.

Question 7

Describe succulence as an adaptation found in halophytes.

Answer 7

The development of water storage structures in the leaves and other parts of the plant dilutes the salt content of the cells.

Question 8

WHat are problems halophytes experience in obtaining water from soil with a high soil salinity?

Answer 8

• Salt concentration in the soil exceeds that in the roots.
• Therefore, water moves from the roots into the soil.
• Water moves by osmosis.
• To equal concentrations of salt inside and outside the root.
• Therefore, the plant losses water.