Which of the following will not cause the stomata to close?

1. wilting

2. increase in carbon dioxide concentration

3. darkness

4. increase in pH

Pick the incorrect statement

1. Guard cells help balance the photosynthesis-transpiration compromise.

2. Water tension in a transpiring plant will exert a pull on water molecules lower down in the plant's vascular system.

3. Plants that live in deserts have adapted to constant water stress by using hydrophilic colloids to increase the water potential of their tissues.

4. C3 plants can fix double the carbon dioxide for half the water transpired.

What seems to be the most valid statement about root pressure?

1. It is the positive pressure responsible for transport of water most commonly.

2. It may provide a considerable push to the water column during transport.

3. It may help re establish the broken water columns during transpiration

4. Its effect is most observable during mid day

A structural attribute of guard cells that aid in its effective functioning is

1. Large cell size

2. Radial micellation in walls

3. Thick walls

4. All of the above

Not an aid to water absorption is

1. The high surface area of roots

2. High water potential of root hair cells

3. Thin cellulosic walls of root hair zone

4. Low concentration of solutes in the soil

The water is free to move between the cells except through the

1. xylem

2. epidermis

3. endodermis

4. pericycle

Continuity of protoplasm in sieve elements is maintained through

1. Cytoplasmic strands

2. P proteins

3. Vacuoles

4. Walls

Which is not an advantage of transpiration.

1. Maintains shape of cells by keeping them turgid

2. Cools down plant surfaces by evaporative cooling

3. Transports minerals.

4. None of the above.

One of the following is not a pre-requisite for transpiration?

1. high Vapour pressure deficit of atmosphere

2. Low atmospheric humidity

3.High soil water potential 

4. Sunny weather

A manifestation of root pressure is

1. Guttation

2. transpiration

3. Cohesion

4. Negative hydrostatic pressure