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प्रश्न
Some plants like pea plants have tendrils which help them to climb up other plants. Explain how is it done. Name the plant hormone responsible for this movement.
उत्तर
A tendril is a short stem- or petiole-like structure utilised by vines and climbing plants to wrap around or hook a support. Auxin is a growth hormone that is often synthesised near the shoot tip. It promotes cell development, allowing plants to grow longer. When the tendril comes into touch with any support system, auxin stimulates the cell on the opposite side to grow faster, causing the tendril to form a coil around the support.
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संबंधित प्रश्न
What is the stimulus in chemotropism?
Give the scientific terms used to represent the Bending of roots towards water.
Define geotropism.
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
Which of the following are not tropisms?
(i) growing of pollen tube in response to a sugary substance
(ii) folding up of leaves of sensitive plant in response to touch
(iii) winding of tendril around a support in response to touch
(iv) opening up of the leaves of a daisy flower in response to light
(a) (i) and (ii) (b) (ii) and (iii) (c) (i) and (iv) (d) (ii) and (iv)
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.
A growing seedling is kept in the dark room. A burning candle is placed near it for a few days. The tip part of the seedling bends towards the burning candle. This is an example of ______.
The growth of pollen tubes towards ovules is due to
Give an example of chemotropism.
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.
