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प्रश्न
What is meant by positive tropism and negative tropism? Explain with examples.
उत्तर
If the movement of the response is towards the stimulus, it is known as positive tropism; whereas if the movement of the response is in the direction opposite to the stimulus, it is is known as negative tropism.
The movement of roots towards the pull of gravity is an example of positive geotropism, whereas the movement of plant stem in the direction opposite to the pull of gravity is an example of negative geotropism.
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संबंधित प्रश्न
What does a stem (or shoot) do in response to gravity? What is this phenomenon known as?
Distinguish between tropic movements and nastic movements in plants. Give examples to illustrate your answer.
A plant's response to gravity is called ______.
There are three plants A, B and C. The flowers of plant A open their petals in bright light during the day but close them when it gets dark at night. On the other hand, the flowers of plant B open their petals at night but close them during the day when there is bright light. The leaves of plant C fold up and droop when touched with fingers or any other solid object.
- Name the phenomenon shown by the flowers of (i) plant A and (ii) plant B.
- Name one flower each which behaves like the flower of (i) plant A and (ii) plant B.
- Name the phenomenon exhibited by the leaves of plant C.
- Name a plant whose leaves behave like those of plant C.
- Which plant/plants exhibit the phenomenon based on growth movements?
What are tropic movements? Briefly explain various types of tropic movements in plants.
The growth of tendrils in pea plants is due to
Write the scientific terms used to represent the following:
Bending of roots towards the water.
While conducting experiments to study the effects of various stimuli on the plants, it was observed that the roots of 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 stimulus A and B but bends towards the stimulus C. The stimulus B is known to act on the roots due to factors related to Earth. Keeping these points in mind, answer the following questions:
- What could be stimulus A?
- Name the stimulus seen in B.
- What could be stimulus-C?
List two differences between the movement of leaves of a sensitive plant and the movement of a shoot towards light.
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.
