Tag: basics of roots and stem

Questions Related to basics of roots and stem

The bulliform cells of leaves lose their turgidity during excessive _____________.

  1. Assimilation

  2. Transpiration

  3. Photosynthesis

  4. Respiration


Correct Option: B
Explanation:

In some grasses(isobilateral leaves), on epidermis, there are some larger, thin walled cells called bulliform cells are present, which in dry condition lose water through transpiration and thus the rolling up of leaves occurs, e.g., in Poa, Agropyron, Amophilla, etc.

How much water a mango tree can transprire during its growing season?

  1. $350 - 750$ liters/ day

  2. $350 - 1750$ liters/ day

  3. $750 - 3500$ liters/ day

  4. $1750 - 3500$ liters/ day


Correct Option: A
Explanation:
Mango tree transpire around 100L of water per day during normal season But this transpiration reaches to 350-750 L /day during is a growing season.
So the correct option is' 350 -750liters /day'.

Meaningful girdling (ringing) experiment can not be performed within sugarcane because

(a) its phloem is situated interior to xylem
(b) its stem surface is covered with worry coating
(c) its vascular bundles are not present in a ring
(d) its stem is thin $13$. Guttation is caused by

  1. Transpiration

  2. Osmosis/ DPD

  3. Root pressure

  4. Osmotic pressure


Correct Option: C
Explanation:
Guttation is the process of loss of water from the surface of leaves in the form of liquid drops. Hydathodes are the openings through which guttation takes place that are present on the margins of leaves. It occurs when root pressure is high and transpiration is low. 
So the correct answer is 'Root pressure'.

In the leaves of strawberry, water appears to be exuded through leaf margins. This is due to the combination of:
i. Adhesion
ii. Root pressure
iii. Transpiration
iv. Guttation.

  1. i, ii and iii

  2. ii, iii and iv

  3. i, ii and iv

  4. Only i, & iv


Correct Option: C
Explanation:
  • Guttation is the process of loss of water from the surface of leaves in the form of liquid drops. Hydathodes are the openings through which guttation takes place that are present on the margins of leaves.
  • Guttation occurs when root pressure is high and transpiration is low. Guttation is frequently seen occurring at night in herbaceous plants growing under conditions of high soil moisture and high atmospheric humidity.
  • Water rises up in the process due to the property of Adhesion.
So, the correct option is 'i, ii and iv'.

Transpiration.

  1. There are stomata on the leaves of the plants.Through these opening the excess of water is thrown out in the form of water vapors. This process is called transpiration

  2. There are two guard cells around the opening of stomata.They have an external membrane. They control the opening and closing of the stomata.

  3. Also come amount of water is lost due to evaporation from the leaves.

  4. As a result, water level in the epidermal layer of the leaf decrease

  5. To compensate this loss,more water is brought to the leaves through the xylem.

  6. Transpiration thus helps in absorption of water and minerals and their distribution to all parts of the plant

  7. Root pressure pushes the water up during the night time.


Correct Option: A

The droplets of water arranged at the edges of leaves of roses in the morning are

  1. Water drops condensed from the atmosphere during night at low temperatures

  2. Water transpired from the stomata and lenticels

  3. Water produced on the leaves from the reaction of hydrogen and atmospheric oxygen

  4. None of the above


Correct Option: B
Explanation:
Water droplets formed on the edge, tip, or the underside of leaves is not dew because dew comes from water condensing from the air and tends to settle evenly on the leaf’s upper surface.
Transpiration is the evaporative loss of water by plant. When the soil is too wet, water penetrates the plant through its roots and this creates pressure that forces the water to exit the plant in the form of droplets. This process doesn’t occur during the day, because the leaf’s stomata are open at that time. It occurs when the stomata close down, i.e. at night and water pressure begins to build up. Therefore, the droplets can be noticed when the sun comes up in the morning, before the drops evaporate.
So, the answer is B.

Transpiration is mainly a process of ______________.

  1. Imbibition

  2. Respiration

  3. Osmotic pressure

  4. Diffusion


Correct Option: D

Wilting occurs when there is ___________________.

  1. Transpiration higher than absorption

  2. Absorption higher than transpiration

  3. Higher relative humidity of atmosphere

  4. Excess root pressure


Correct Option: A

The process of loss of water through the leaves and stem is called

  1. Transpiration

  2. Respiration

  3. Photosynthesis

  4. Pollination


Correct Option: A
Explanation:

Transpiration is the processin which water vapours are released from stomata.

Respiration is a metabolic processes which breaks down complex organic molecules to release energy.
Photosynthesis is the synthesis of sugar in the presence of sunlight, carbon dioxide and water.
Pollination is the transfer of pollen from male organ to female organ of a flower. 
So the correct answer is 'Transpiration'.

In transpiration, water is lost in         form whereas in guttation water is lost in the form of          

  1. Vapour, liquid

  2. Liquid, vapour

  3. Solid, vapour

  4. Vapour, solid


Correct Option: A
Explanation:

In transpiration water is lost in the form of vapour whereas in guttation water in the form of liquid is lost. The loss of water in transpiration is through stomata whereas in guttation, it occurs through hydathodes.