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प्रश्न
What is a tropic movement? Explain with an example.
उत्तर
The movements which are in a particular direction in relation to the stimulus are called tropic movements. Tropic movements happen because of growth of a plant in a particular direction. There are four types of tropic movements, viz. geotropic, phototrophic, hydrotropic and thermotropic.
Example: Roots usually show positive geotropic movement, i.e., they grow in the direction of the gravity. Stems usually show negative geotropic movement.
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संबंधित प्रश्न
Give one example of chemotropism. State whether this example is of positive chemotropism or negative chemotropism.
Plant shoot grows upward in response to ______.
The response of leaves to the sunlight is called ______.
The bending of the root of a plant away from a source of light is caused by a plant hormone called :
(a) cytokinin
(b) gibberellin
(c) abscisic acid
(d) auxin
P and Q are two types of plants having weak stems which cannot stand upright on their own. The plants P and Q have organs R and S respectively which can grow towards any support which they happen to touch and wind around that support. It is observed that organ R originates from the leaves of the plant whereas organ S originates directly from the stem of the plant.
(a) What is (i) R, and (ii) S?
(b) What is the name of growth movement exhibited by the organs R and S?
(c) Name the stimulus involved in this case.
(d) State whether the behaviour of organs R and S is a tropic movement or a nastic movement.
(e) Name one plant like P and another plant like Q.
Thigmonasty can be seen in ______.
Name the phenomenon occurring in plants which are under the control of gravity, water and chemicals with one example each that shows the movement involved.
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 ______.
Differentiate between:
Positive and negative tropism
