Advertisements
Advertisements
Question
The root of the plant is ______.
- positively phototropic but negatively geotropic
- positively geotropic but negatively phototropic
- negatively phototropic but positively hydrotropic
- negatively hydrotropic but positively phototropic
Options
(i) and (ii)
(ii) and (iii)
(iii) and (iv)
(i) and (iv)
Solution
(ii) and (iii)
APPEARS IN
RELATED QUESTIONS
What happens to the dandelion flower
- during the daytime, and
- at night?
What is this phenomenon known as?
Why is the folding up of the leaves of a sensitive plant on touching with a finger not a tropism?
What is meant by 'tropisms' (or tropic movements)? Explain with an example.
The climbing organs of plants like tendrils grow towards any support which they happen to touch and wind around the support. This is an example of :
(a) chemotropism
(b) nastic movement
(c) thigmotropism
(d) geotropism
The chemical substance P is made and secreted by the meristematic tissue at the tip of stem (or shoot) of a plant. The chemical substance P is responsible for a phenomenon Q in plants in which the stem bends towards a source of light. The same chemical substance P has an opposite effect on the root of a plant. It causes the root of a plant to bend away from the source of light in a process called R.
(a) What is the chemical substance P?
(b) State whether P prefers to remains in the sunlit side of a stem or in shade.
(c) What is the effect of substance P on the rate of growth of (i) a root, and (ii) a stem?
(d) What is the name of process (i) Q, and (ii) R?
(e) What is the general name of chemical substances like P? Name another substance which belongs to this class of chemical substances.
A potted plant having straight parts A and B was placed horizontally on its side as shown in Figure (i). After a few days, it was observed that parts A and B of the plant acquired new positions as shown in Figure (ii).
- Name the phenomenon exhibited by the position of plant parts A and B in Figure (ii).
- Name the stimulus (other than sunlight) which causes plant part A to grow and bend upwards, and plant part B to bend downwards.
How is movement in plants different from that in animals?
Answer the following question.
What is tropism?
Differentiate phototropism from photonasty.
Arrange and rewrite the terms in the group in the correct order so as to be in a logical sequence, beginning with the term that is underlined.
Apical meristem, Positive phototropism, Auxins, Cell elongation.