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प्रश्न
What is meant by positive phototropism and negative phototropism? Give one example of each type.
उत्तर
The movement of plant parts towards the light source is known as positive phototropism, whereas the movement of plant parts away from light is known as negative phototropism. The stems of plants show positive phototropism as they grow upwards. The roots of plants show negative phototropism as they grow downwards into the soil.
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संबंधित प्रश्न
Where is the auxin hormone made in a plant stem?
How are tropic movements helpful to plants? Explain with an example.
The growth of a pollen tube towards the ovule caused by a sugary substance as stimulus is an example of :
(a) phototropism
(b) chlorotropism
(c) gravitropism
(d) chemotropism
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 bending of the stem of a plant towards a source of light is caused by the action of a phytohormone known as :
(a) abscisic acid
(b) auxin
(c) gibberellins
(d) cytokinin
The Scientific term used to represent the bending of roots toward water is called geotropism.
When the leaves of the Mimosa pudica plant are touched with a finger, they fold up quickly.
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?
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.
Growth of root towards water is ______.
