Q. 725.0( 1 Vote )
While conducting experiments to study the effect of various stimuli on the plants, it was observed that the roots of a 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 stimuli A and B but bends towards the stimulus C. The stimulus B is known to act on the roots due to too much weight of the earth. Keeping these points in mind, answer the following questions:
(a) What could stimulus A be?
(b) Name the stimulus B.
(c) What could stimulus C be?
(d) The branches of a fallen tree in a forest grow straight up in response to two stimuli. What could be these two stimuli out of A, B and C? Also name these two stimuli.
(a) Stimulus A could be water as roots show the positive hydrotropism.
(b) Stimulus B could be gravity as roots show the positive geotropism.
(c) Stimulus C could be light as roots show the negative phototropism.
(d) The two stimuli could be B (gravity) and C (light).
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Following are the two examples of plant movement.
(i) Which stimulus is common for movement in both the cases?
(ii) Does the movement take place towards the point where the stimulus is received? Mention separately for both plants.
(iii) Give one reason for the movement is each case.All In One Science
A plant in the laboratory is given an increased dose of a hormone, which promotes the development of seedless fruits. Identify the hormone and write its other two functions.All In One Science
How is geotropism necessary for the plant?All In One Science
How does phototropism occur in a plant stem (or shoot)? Explain with the help of labelled diagrams.Lakhmir Singh & Manjit Kaur- Biology