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प्रश्न
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.
उत्तर
A plant always grows its roots downward in reaction to gravity. Geotropism is the name given to this occurrence. A plant root will always gravitate towards water in response to it. The name for this occurrence is positive hydrotropism. During fertilisation, the ovule releases chemicals that cause the pollen tube to expand in the direction of the ovule, a phenomenon known as chemotropism.
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संबंधित प्रश्न
Name the type of chemical substances that control the growth in plants.
What does a root do in response to light? What is this phenomenon known as?
Name the two types of tendrils.
What is meant by positive phototropism and negative phototropism? Give one example of each type.
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.
The bending of root of a plant in response to water is called ______.
What is a tropic movement? Explain with an example.
The plant part which exhibits negative geotropism is ______.
Define the following term:
Tropism
Study the diagrams given below and answer the following questions:
- Name the structures shown as X and Y in the figures (A) and (B), respectively.
- Write the functions performed by the structures X and Y.
- Name the phenomenon depicted and define it.
- How do the structures X and Y differ from each other?
- Give examples of the plants which show the said phenomenon.
