Water logging or over-watering a plant is dangerous and may kill the plant. Why is this so?

1. Water does not have all the necessary minerals a plant needs to grow.
2. Water neutralizes the pH of the soil.
3. The roots are deprived of oxygen.
4. Water lowers the water potential of the roots.

Which of the following is/are essential for imbibitions to take place?

I. Water potential gradient between the absorbent and the liquid imbibed

II. Affinity between the adsorbant and the liquid

1. Only II

2. Only I

3. Both I and II

4. None

Consider the following:

I.    A decrease in pressure on cell exerted by the wall
II.   An increase in water potential of the surroundings
III.  The uptake of solutes by the cell
IV.  An increase in the tension on the surrounding solution

Which of the above would contribute to the uptake of water by the cell?

1. I, II, III

2. II, III, IV

3. I, II, IV

4. I, III, IV

What is true for both symplast and apoplast movement of water in plants?

1. An equal rate of transport

2. Being down a potential gradient

3. Assistance by cytoplasmic streaming 

4. Conduction through interconnected protoplasts

Phenyl mercuric acetate (PMA) results in

1. reduced photosynthesis

2. reduced transpiration

3. reduced respiration

4. killing of plants.

Pressure on a plant cell wall caused osmotic movement of water is called:

1. Osmotic pressure

2. Osmotic potential

3. Turgor pressure

4. Hypertonic pressure

The most abundant solute in the phloem sap is :
1. Potassium ions
2. Sucrose
3. Glucose
4. Starch

A plant requires potassium for:

(1) Holding its cells together

(2) Synthesizing chlorophyll

(3) DNA replication

(4) Opening and closing its stomata

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

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