Biology

Plant Transport and Physiology

2,012 Questions

Access a comprehensive set of questions on plant transport mechanisms and physiological adaptations. Topics include water movement, translocation of food, and plant responses to external stimuli. These biology questions are essential for medical entrance exams and other science competitive tests.

Xylem and phloem transportTranspiration and evaporationPlant adaptationsGeotropic and phototropic responsesWater absorption by rootsRespiration in roots

Plant Transport and Physiology Questions

Multiple choice botany transpiration guttation excretion in plants long distance transport of water

Water drops present on leaf margins of Tropaeolum, balsam and grasses in early morning are due to

  1. Guttation

  2. Dew

  3. Osmosis

  4. Transpiration
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Guttation is the loss of water in liquid form through hydathodes. Guttation is usually seen under environmental conditions when transpiration is low and soil is well watered. It occurs under the influence of positive root pressure. Water droplets present on leaf margins of some plants in the early morning is not due drops but the water that has oozed out from xylem tracheids. 

Multiple choice botany transpiration guttation excretion in plants long distance transport of water

Guttation drops can be differentiated from dew drops

  1. By taste

  2. As dew drops will be seen

  3. As guttation drops will be restricted on the margins of the leaf

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Guttation is the loss of water in liquid form through hydathodes. Guttation is usually seen under environmental conditions when transpiration is low and soil is well watered. It occurs under the influence of positive root pressure. Water droplets present on leaf margins of some plants in the early morning is not due drops but the water that has oozed out from xylem tracheids. Xylem tracheids contain dissolved minerals in the water. Hence water lost in guttation is not pure water but a solution of minerals and will not be tasteless as the pure water of dew drops.

Multiple choice botany transpiration guttation excretion in plants long distance transport of water

Loss of water from tips of leaves is called as

  1. Bleeding

  2. Guttation

  3. Respiration

  4. Transpiration
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Loss of water in vapour form through stomata is called as transpiration. Loss of water in solution form through vein endings in leaves is called as guttation. Transpiration occurs under the influence of vapour pressure gradient. Guttation is caused due to root pressure when soil is well watered and transpiration is low due to high atmospheric humidity.

Multiple choice botany transpiration guttation excretion in plants long distance transport of water

Water lost in guttation is

  1. Pure water

  2. Impure water

  3. In vapour form

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Guttation is the loss of water in solution form through hydathodes. It occurs under the influence of root pressure. When transpiration is low and plant absorbs water from well-watered soil under the influence of root pressure. The excess water oozes out as a dilute solution of minerals and other solutes from dead endings of veins. Thus, the correct answer is option B.

Multiple choice botany transpiration guttation excretion in plants long distance transport of water

The hydathodes are related with

  1. Transpiration

  2. Guttation

  3. Bleeding

  4. All of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Guttation is defined as loss of water in liquid form through water stomata or hydathodes. The water is lost as a dilute solution of mineral salts. Guttation occurs under the influence of positive root pressure.

Multiple choice botany transpiration guttation excretion in plants long distance transport of water

Guttation takes place through

  1. Lenticels

  2. Pneumatophores

  3. Stomata

  4. Hydathodes
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Guttation is the loss of water in the form of the dilute solution which consists salts and minerals through stomata or hydathodes. Guttation occurs under the influence of root pressure when soil is well watered but humidity is high consequently transpiration is less.

Multiple choice botany transpiration guttation excretion in plants long distance transport of water

Which of the following is not a rhythmic phenomenon?

  1. Stomatal opening and closing

  2. Guttation

  3. Nyctinasty

  4. Photonastic movement
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The movements showed by plants can be classified broadly as
(1) Hygroscopic- due to loss or gain of water and
(2) Vital- due to irritability of the cytoplasm. 
Nyctinasty or sleep movements are rhythmic movements, also called as sleep movements and are caused by relative changes in cell size on the opposite sides of the leaf base called as pulvinus. 

Photonasty is the nastic movement caused in response to light. 
Guttation is the loss of water in solution through hydathodes. This is not an example of rhythmic movement and depends on environmental conditions. Thus, the correct answer is option B.

Multiple choice botany transpiration guttation excretion in plants long distance transport of water

Which condition favours guttation?

  1. High water absorption

  2. High transpiration

  3. Low transpiration

  4. Both A and C
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Guttation is the loss of water through water stomata (hydathodes) in solution form as a dilute solution of mineral salts. This process occurs, when the absorption of water exceeds transpiration i.e., when plants are absorbing water actively. A positive root pressure is built up under the influence of which excess water simply oozes out through the dead ends of xylem tracheids and vessels. Thus, the correct answer is option D.

Multiple choice botany transpiration guttation excretion in plants long distance transport of water

Water of guttation is

  1. Pure water

  2. Water with dissolved salts

  3. Solution of organic food

  4. Condensed water vapour
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Guttation is the loss of water in solution form through hydathodes. The water lost in guttation is a dilute solution of mineral salts. The guttation occurs under the influence of positive root pressure and depends on environmental conditions. It is generally observed when atmospheric humidity is high so that rate of transpiration is low and soil is well watered. Thus, the correct answer is option B.

Multiple choice botany transpiration guttation excretion in plants long distance transport of water

Guttation usually occur in a well watered herbaceous plant and well drained soil during

  1. Early morning hours

  2. Evening hours

  3. Noon hours

  4. Day hours
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Guttation is the loss of water through water stomata (hydathodes) in the form of the dilute solution of mineral salts. When the absorption of water exceeds transpiration i.e., when plants are absorbing water actively, a positive root pressure is built up under the influence of which excess water simply oozes out through the dead ends of xylem tracheids and vessels. This usually happens during early morning hours when transpiration is low.

Multiple choice botany transpiration guttation excretion in plants long distance transport of water

Guttation occurs when plants absorb water through

  1. Active absorption

  2. Passive absorption

  3. Root pressure

  4. Both A and C
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

When the plant absorbs water by their own, it is called active absorption. It takes place when transpiration is low and amount of water in the soil is high. In this case root hairs play the major role in the absorption of water. Root pressure is the positive pressure that develops in the roots of plants by the active absorption of nutrients from the soil. It causes sap to rise through a plant stem to the leaves. Guttation is the exudation of xylem sap on the tips or edges of leaves of some vascular plant. According to the passive absorption, root hairs do not play any role in absorption. It takes place only when transpiration rate is high. So, the correct option is D.

Multiple choice botany transpiration guttation excretion in plants long distance transport of water

The process of escape of the liquid from the tip of uninjured leaf or through hydathodes is called as

  1. Transpiration

  2. Guttation

  3. Evapo-transpiration

  4. Evaporation
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Guttation is the excretion of drops of xylem sap on the tips or edges of leaves of some vascular plants, such as grasses. It is the loss of water in liquid form through hydathodes.

Therefore, the correct answer is option B.

Multiple choice botany transpiration guttation excretion in plants long distance transport of water

Loss of water from the tip of the leaf pores in a plant is known as 

  1. Transpiration.

  2. Guttation.

  3. Evaporation.

  4. Respiration.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The soil rich in moisture content, water floods a plant root system. Leaves can retain only a finite amount of water. Excess water i.e xylem sap is given out from the roots through pores or edge of leaves and this process is called guttation. Thus the correct answer is option B.

Multiple choice botany transpiration guttation excretion in plants long distance transport of water

Transpiration occurs through .......... and guttation occurs through .......... in the plants.

  1. Hydathodes, stomata

  2. Stomata, cuticle

  3. Stomata, hydathodes

  4. Hydathodes, lenticles
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Transpiration is the process in which water vapors are released from the stomata. Guttation is the process of release of water droplets from the hydathodes.

So, the correct answer is 'Stomata, hydathodes'.

Multiple choice botany transpiration guttation excretion in plants long distance transport of water

Guttation is caused due to

  1. Imbibition

  2. Osmosis

  3. Positive root pressure

  4. Transpiration
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Guttation is the loss of water in liquid form as a dilute solution from uninjured leaf tips. The uninjured leaf tips have hydathodes or water stomata. Under conditions of low transpiration dilute solution of minerals oozes out through them under the influence of increased root pressure.