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प्रश्न
Dandelion flowers open the petals in bright light during the daytime but close the petals in dark at night. This response of dandelion flowers to light is called:
विकल्प
phototropism
thigmonasty
chemotropism
photonasty
उत्तर
photonasty
Explanation
The response of dandelion flowers to light that involves the movement of the petals is an example of photonasty.
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संबंधित प्रश्न
What is the stimulus in thigmotropism?
Define chemotropism.
What is the difference between thigmotropism and thigmonasty? Name one plant which exhibits thigmotropism and one plant which exhibits thigmonasty. What behaviour (or responses) of these plants make you think that they exhibit thigmotropism and thigmonasty respectively?
P, Q, R and S are four major types of phytohormones. P is a phytohormone which functions mainly as a growth inhibitor. It promotes the wilting and falling of leaves. Q, R and S are phytohormones which all promote growth of plants in various ways. Q is responsible for the phenomenon of phototropism in plants. R is involved mainly in shoot extensions. The phytohormone S helps in breaking the dormancy of seeds and buds. What are P, Q, R and S? Give one reason each for your choice.
Assertion (A): If the plant part moves in the direction of gravity, it is called positive geotropism.
Reason (R): Stem shows positive geotropism.
Write the scientific terms used to represent the following:
Bending of roots towards the water.
Give an example for the movement of plant part which is very quick and can be observed easily.
Give one example of geotropism.
Ali has some pea plants in his garden which need a support to grow as seen in the picture given below:
- Name the phenomenon depicted by the shoot in the given figure.
- Define the above phenomenon.
- Write the name of the part marked X.
Define the following term:
Clinostat
