Advertisements
Advertisements
Question
The movement of sunflower in accordance with the path of the sun is due to :
(a) photonasty
(b) phototropism
(c) hydrotropism
(d) chemotropism
Solution
(a) photonasty
It is a non-directional movement of plant parts in response to light.
APPEARS IN
RELATED QUESTIONS
What is the stimulus in hydrotropism?
A big tree falls in a forest but its roots are still in contact with the soil.
The branches of this fallen tree grow straight up (vertically). This happens in response to ______.
Which of the following is not caused by a growth movement?
Which of the following are not tropisms?
(i) growing of pollen tube in response to a sugary substance
(ii) folding up of leaves of sensitive plant in response to touch
(iii) winding of tendril around a support in response to touch
(iv) opening up of the leaves of a daisy flower in response to light
(a) (i) and (ii) (b) (ii) and (iii) (c) (i) and (iv) (d) (ii) and (iv)
While conducting experiments to study the effect of various stimuli on the plants, it was observed that the roots of a plant X grow and bend towards two stimuli A and B but bend away from a third stimulus C. The stem of the plant X, however, bends away from stimuli A and B but bends towards the stimulus C. The stimulus B is known to act on the roots due to too much weight of the earth. Keeping these points in mind, answer the following question:
- What could stimulus A be?
- Name the stimulus B.
- What could stimulus C be?
- The branches of a fallen tree in a forest grow straight up in response to two stimuli. What could be these two stimuli out of A, B and C? Also name these two stimuli.
The plant part which exhibits negative geotropism is ______.
Analogy:
Towards a stimulus: ______:: Away from the stimulus: Negative tropism.
Write the scientific terms used to represent the following:
Growing of roots towards the gravity.
Write the scientific terms used to represent the following:
Bending of roots towards the water.
Give one example of geotropism.
