Absorption of Water_MCQ_ Advance Level

Absorption of water - Advance

Dear Readers,

As transpiration proceeds, water absorption occurs simultaneously to compensate the water loss from the leaf end. ... The water will enter the plant via the root cells that can be found in the roots where mainly passive absorption occurs. Also, with the absorption of water, minerals and nutrients are also absorbed.

Q1.  Water potential found in root hair cells is generally

•  1–2 atm.
•  –1 to 2.0 atm.
•   –1 to 4 atm.
•  –1 to –4 atm.

–1 to –4 atm.

Q2. If the rates of transpiration and water absorption of a flowering plant are measured over a period of twenty four hours, it is found that the rate of transpiration reaches its peak at about mid-day and then declines, whereas the peak for water absorption is reached approximately two hours later. Which one the following statements provides the best explanation of these results

•  There is a temporary reduction of light intensity at mid-day, which reduces the rate of transpiration
•  Water absorption is mainly due to root respiration and this is affected by soil temperature, which does not reach a maximum for some hours after the maximum air temperature has been reached
•  The high rate of transpiration causes a water deficit which results in stomatal closure and an increased concentration of leaf cell sap, which in turn causes continued water uptake
•  The high light intensity results in high internal oxygen concentrations and so increase water uptake

The high rate of transpiration causes a water deficit which results in stomatal closure and an increased concentration of leaf cell sap, which in turn causes continued water uptake

Q3.  Which of the following helps in the absorption of water and mineral salts

•  Mycorrhiza
•  Anabaena
•  Nostoc
•  None of these

Mycorrhiza

Q4.  Which of the following water comes under echards

•  Available to the plant
•  Whole of the soil water
•  Amount of water not available to the plant
•   None of these

Amount of water not available to the plant

Q5.  Root cap has no function in water absorption, because

•  Its vascular system is not directly connected
•  Its cells are loosely placed
•  It has cells without chloroplast
•  It has no root hair

It has no root hair

Q6.  Suitable temperature for active absorption of water by root is

•  40 – 45°C
•   10 – 15°C
•   20 – 30°C
•  Can take at any temperature

20 – 30°C

Q7.  In a young root, the most active absorption of water takes place through

•   Root cap region
•  Root hair region
•  Zone of elongation
•   Mature region with a corky cover

Root hair region

Q8.  Root hairs occur in the zone of

•  Cell division
•  Cell elongation
•  Cell maturation
•  Calyptrogen

Cell maturation

Q9.  Soil moisture beyond field capacity produces a condition of

•  Temporary wilting
•  Permanent wilting
•  Water logging
•  Both (a) and (b)

Water logging

Q10.  Contribution of passive water absorption to total water absorption is

•  50%
•  70%
•  80–90%
•  96–100%

96–100%