Water and Solute movement

Question 1

What are examples of drought sensitive plants?

Answer 1

Rice. wheat

Question 2

What are some examples of drought tolerant plants?

Answer 2

Cacti, succulents

Question 3

What is an example of a resurrection plant?

Answer 3

Tripogon

Question 4

What is the category of plants that can survive even lith <5% relative water content?

Answer 4

Desiccation tolerant or resurrection plants.

Question 5

Why is water so important for plants?

Answer 5

• Makes up 80-95% of tissues
• Helps transfer food, essential nutrients around the plant

Question 6

What is the process that induces the opening of stomata?

Answer 6

• Detection of blue light/shade or non intense light
• Influx of potassium
• Accumulation of solutes in the guard cells
• Stomata opens

Question 7

What is the process that induces the closing of stomata?

Answer 7

• Water loss stres and abscisic acid
• Efflux of postassium
• Decline in solutes in guard cells
• Closing of stomata

Question 8

What are some influences that cause stomatal closure?

Answer 8

• Increased CO2 concentration
• High temp

Question 9

What is bulk flow?

Answer 9

The movement of water as being pulled by other moving water molecules.

Question 10

What are aquaporins?

Answer 10

Regulated, membrane-bound water channels.

Question 11

What do aquaporins do?

Answer 11

Help facilitate rapid plant movements, such as motor cells.

Question 12

Apoplastic pathway?

Answer 12

water moves through cells walls but remains outside the cell membrane

Question 13

Symplastic pathway?

Answer 13

water travels inside cells and moves to the next cell via plasmodesmata

Question 14

Transcellular pathway?

Answer 14

water moves sequentially from one cell to the next by crossing membranes

Question 15

What is the endodermis?

Answer 15

band of cells around the vascular tissue of the roots.
Water and solutes must cross endodermis cell membranes to reach the xylem.

Question 16

What is the Casparian strip?

Answer 16

cell walls of endodermis impregnated with suberin to form a barrier to water and solute movement

Question 17

What are the two functions of companion cells?

Answer 17

Responsible for loading and unloading sugars and other compounds from sieve elements/to sink

Takes over critical metabolic functions that are reduced or lost in sieve elements

Question 18

What is translocation?

Answer 18

The process whereby the products of photosynthesis are transported through phloem.

Question 19

What is a sugar source?

Answer 19

An organ that produces sugar, such as mature leaves.

Question 20

What is a sugar sink?

Answer 20

An organ that is a consumer of sugar yet does not produce such as a tuber or bulb or fruit.

Question 21

What is phloem loading?

Answer 21

The movement of photosynthates from mesophyll chloroplasts to sieve elements of mature leaves.

Question 22

What are the 3 steps in phloem loading?

Answer 22

(i) Sucrose synthesis
(ii) Short-distance transport
(iii) Sieve element loading