The water potential of pure water is

(1) zero

(2) less than zero

(3) more than zero, but less than one

(4) more than one

Which of the following facilitates opening of stomatal aperture :-

(1) Contraction of outer wall of guard cells

(2) Decrease in turgidity of guard cells

(3) Radial orientation of cellulose microfibrils in the cell wall of guard cells

(4) Longitudinal orientation of cellulose microfibrils in the cell wall of guard cells

A few drops of sap were collected by cutting across a plant stem by a suitable method. The sap was tested chemically. Which one of the following test results indicates that it is phloem sap?

(1) Acidic

(2) Alkaline

(3) Low refractive index

(4) The absence of sugar

Root pressure develops due to

1. active absorption

2. low osmotic potential in soil

3. passive absorption

4. increase in transpiration

Transpiration and root pressure cause water to rise in plants by

1. Pulling it upward

2. pulling and pushing it, respectively

3. pushing it upward

4. pushing and pulling it, respectively

Which of the following criteria does not pertain to facilitated transport?

1. Requirement of special membrane proteins

2. High selectivity

3. Transport saturation

4. Uphill transport

Which one of the following elements in plants is not remobilised?

1. Calcium

2. Potassium

3. Sulphur

4. Phosphorus

The rupture and fractionation do not usually occur in the water column in vessel/tracheids during the ascent of sap because of

1. lignified thick walls

2. cohesion and adhesion

3. weak gravitational pull

4. transpiration pull

The translocation of organic solutes in sieve tube members is supported by:

1. root pressure and transpiration pull

2. P-proteins

3. mass flow involving a carrier and ATP

4. cytoplasmic streaming

Which of the following facilitates opening of stomatal aperture?