Biology
The figure given below depicts a kind of tropic movement in plants. Study the same and answer the following questions.
(a) What kind of a movement is shown in figure. Define it.
(b) How does this movement differ from geotropism?
(c) Name the stimulus responsible for thigmotropism. Give one example of a plant showing thigmotropism.
(d) Name one stimulus which gives a positive response for the roots but negative response for the shoot.
(e) Draw a neat and labelled diagram of the part of plant showing leaf tendril. Name the plant.
Chemical Coordination in Plants
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Answer
(a) Phototropism.
It is defined as the movement in response to the stimulus of light.
(b) Stimulus for phototropism is light whereas for geotropism it is gravity.
(c) Touch is the stimulus for thigmotropism.
Example — The tendrils of sweet pea plant start coiling around the support in response to touch.
(d) Gravity
(e) Sweet pea plant shows thigmotropism. The labelled diagram showing leaf tendril is given below:
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Related Questions
The box given below contains twelve words. Out of these, ten can be arranged in five suitable matching pairs. Make these five pairs in the form of a table.
Auxin, Abscisic acid, Fruit ripening, Cytokinins, Closure of stomata, Parthenocarpy, Ethylene, Gibberellins, Tropism, Stem elongation, Cuscuta, Cell division The diagram given alongside shows a type of tropism. Study the same and answer the questions that follow:
(a) Name and define the type of tropism shown in the diagram.
(b) Label the guidelines (1) to (4).
(c) Name two effective stimulants that help in the growth of part (2).
(d) Name two groups of plants where part (2) grows towards gametophyte with the help of the stimulants mentioned in (c).
Study the diagrams given below and answer the following questions.
(a) Name the structures shown as X and Y in the figures (A) and (B), respectively.
(b) Write the functions performed by the structures X and Y.
(c) Name the phenomenon depicted and define it.
(d) How do the structures X and Y differ from each other?
(e) Give examples of the plants which show the said phenomenon.
Given below are the figures showing some kinds of tropic movements in plants. Study the same and answer the following questions:
(a) Which one of these figures is correct? Give reason in support of your answer.
(b) Name the kind of movements shown by the root system and the shoot system. Define each.
(c) What are the two stimuli which affect root system and shoot system? Name them.
(d) Which of the following stimuli affect the growth of root strongly?
- Gravity
- Water
(e) Draw a neat and labelled diagram of the longitudinal section of a pistil showing chemotropism in an angiospermic plant.