Tag: movements in plants

Questions Related to movements in plants

Following are the misconceptions about root hydrotropism. State whether they are correct or not.
i. The greater growth of roots in moist soil zones than in dry soil zones is not usually a result of hydrotropism. Hydrotropism requires a root to bend from a drier to a wetter soil zone. Roots require water to grow so roots that happen to be in moist soil will grow and branch much more than those in dry soil.
ii. Roots cannot sense water inside intact pipes via hydrotropism and break the pipes to obtain the water.
iii. Roots cannot sense water several feet away via hydrotropism and grow toward it. At best hydrotropism probably operates over distances of a couple millimeters.

biology movement and locomotion in living organisms movements in plants coordination in plants tropic and nastic movements in plants

  1. (i) and (iii) are correct.

  2. (i) and (ii) are correct.

  3. All are correct.

  4. None of the above are correct.

Show answer
Correct Option: C
Explanation:

The greater growth of roots in moist soil zones than in dry soil zones is not usually a result of hydrotropism. Hydrotropism requires a root to bend from a drier to a wetter soil zone. Roots require water to grow so roots that happen to be in moist soil will grow and branch much more than those in dry soil. 
Roots cannot sense water inside intact pipes via hydrotropism and break the pipes to obtain the water. 
Roots cannot sense water several feet away via hydrotropism and grow toward it. At best hydrotropism probably operates over distances of a couple millimeters.

The points given above are true about hydrotropism and it is a common misconception of the same.
Therefore, the correct answer is option C.

Which among the following is an example of chemotropism?

i. Formation of tendrils
ii. Fertilization of flowers by pollen
iii. Growth of plant roots
iv. Falling of leaves

biology movement and locomotion in living organisms movements in plants coordination in plants tropic and nastic movements in plants

  1. (ii) and (iii)

  2. (i) and (iv)

  3. (i) and (ii)

  4. None of these

Show answer
Correct Option: C
Explanation:

  • An example of chemotropic movement can be seen during the growth of the pollen tube, where growth is towards the ovules.
  •  Fertilization of flowers by pollen is achieved because the ovary releases chemicals that produce a positive chemotropic response from the developing pollen tube. 
  • An example of positive and negative chemotropism is shown by plant roots. 
  • The roots grow towards useful minerals displaying positive chemotropism and grow away from harmful acids displaying negative chemotropism. 


Therefore, the correct answer is option C.

Tropic movements are

biology movement and locomotion in living organisms movements in plants coordination in plants tropic and nastic movements in plants

  1. In response to light

  2. In response to gravity

  3. Non-directional

  4. Unidirectional

Show answer
Correct Option: D
Explanation:

Tropic moments are shown according to the direction of stimuli. They do not diffuse and show unidirectional moments.

So the correct option is 'Unidirectional'.

Plants with weak stems like in a cucumber and bitter gourd show

biology movement and locomotion in living organisms movements in plants coordination in plants tropic and nastic movements in plants

  1. Phtototropism

  2. Thigmotropism

  3. Geotropism

  4. Chemotropism

Show answer
Correct Option: B
Explanation:
  • The stem of the plants like cucumber and bitter gourd are very thin and slender. The stem shows the property of thigmotropism. 
  • This is the phenomenon in which there is a movement like the bending or the curling of the stem. 
  • Whenever there is stimulus received in the form of touch, there is curling of the stem and the tendrils of the plant. 
  • This provides support to the plant in climbing against the surfaces.
  • Thus, the correct answer is option B. 

Mimosa pudica displays ______________ movement.

biology movement and locomotion in living organisms movements in plants coordination in plants tropic and nastic movements in plants

  1. Phototropic

  2. Photonastic

  3. Thigmonastic

  4. Thermonastic

Show answer
Correct Option: C
Explanation:

A flexible hinge located at the base of the stalk of the leaf is called as the pulvinus and a sudden loss of turgor pressure in the motor cells of the pulvinus is called as a thigmonastic movement which is seen in Mimosa pudica.

So the correct option is 'Thigmonastic.'

The roots of a coconut tree are seen growing far from the plant. Such a kind of movement of root for want of water is 

biology movement and locomotion in living organisms movements in plants coordination in plants tropic and nastic movements in plants

  1. Phototropism

  2. Geotropism

  3. Chemotropism

  4. Hydrotropism

Show answer
Correct Option: D
Explanation:

The process of hydrotropism is started by the root cap sensing water and sending a signal to the elongating part of the root. Coconut roots usually grow to a depth of close to 0.80 m with 60-90% found in the top 0.5 m of the soil. In 10-year old dwarf coconut grown under rainfed conditions, the effective root zone of absorption was at 1.4 m from the trunk. Coconut has no root hairs but it produces plenty of roots with a large number of rootlets. Coconut tree roots growth is determined by a stimulus or gradient in water concentration. 

So the correct option is 'Hydrotropism'.

Positive geotropic response is __________ shown by roots.

biology movement and locomotion in living organisms movements in plants coordination in plants tropic and nastic movements in plants

  1. Never

  2. Rarely

  3. Mostly

  4. None of the above

Show answer
Correct Option: C
Explanation:

Roots grow mostly positively geotropic. That is, they grow towards the earth. Whereas, shoots are negatively geotropic.

Negative phototropism occurs in

biology movement and locomotion in living organisms movements in plants coordination in plants tropic and nastic movements in plants

  1. Root

  2. Stem

  3. Leaf

  4. Flower

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Correct Option: A
Explanation:
Phototropism is the movement or bending of plants towards light. While roots grow in a direction opposite to that of light and is thus called as negatively phototropic. At the same time, roots grow positively geotropic
So, the correct answer is 'Root'

Protoplasmic streaming movements are referred as 

biology movement and locomotion in living organisms movements in plants coordination in plants tropic and nastic movements in plants

  1. Autonomic movements of locomotion

  2. Thigmonasty

  3. Photonasty

  4. Movements of curvature

Show answer
Correct Option: A
Explanation:

Protoplasmic streaming: Rapid movement of cytoplasm inside the cell. It is an autonomic movement of locomotion. Autonomic movements are the movements which occur due to factors are inherent in plant body.

Phototropism of stem and root are due to 

biology movement and locomotion in living organisms movements in plants coordination in plants tropic and nastic movements in plants

  1. Differential hormonal effect

  2. Epinasty and hyponasty

  3. Effect of light

  4. Graviperception

Show answer
Correct Option: A
Explanation:

Phototropism in stem and root are due to differential phytohormonal effect. Stem grows positively phototropic. Roots grow negatively geotropic. Auxin is responsible for apical dominance and positive phototropism by stem.