Advertisements
Advertisements
Question
One of the following plant hormones is responsible for the phenomenon of phototropism in plants. This is :
(a) gibberellin
(b) eltroxin
(c) cytokinin
(d) auxin
Solution
(d) auxin
Auxin is responsible for the phenomenon of phototropism in plants.
APPEARS IN
RELATED QUESTIONS
Which of the following is a growth movement and which is not?
- Folding up of leaves of sensitive plant on touching with hand.
- Folding up of petals of dandelion flower when light fades.
Plant shoot grows upward in response to ______.
What are the different types of tropisms? Define each type of tropism. Write the name of stimulus in each case
Which of the following is not caused by a growth movement?
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.
Answer the following question.
What is tropism?
Any change in the environment to which an organism responds is called ____________.
In the given figure (a), (b) and (c), which appears more accurate and why?
![]() |
![]() |
![]() |
(a) | (b) | (c) |
Chlorophyll differs from hemoglobin by the presence of its central molecule ______.
Name the following:
The tropic movement of plant parts in response to chemicals.