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प्रश्न
Name the part of plant which shows positive geotropism. Why?
उत्तर
Root shows positive geotropism because of the unidirectional movement in response to gravity.
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संबंधित प्रश्न
What does a tendril do in response to the touch of a support? What is this phenomenon known as?
Why is the folding up of the leaves of a sensitive plant on touching with a finger not a tropism?
Why is the closing of a dandelion flower at dusk (when it gets dark) not a tropism?
Define geotropism.
The bending of the stem of a plant towards a source of light is caused by the action of a phytohormone known as :
(a) abscisic acid
(b) auxin
(c) gibberellins
(d) cytokinin
The top part A of the flask-shaped reproductive organ X in the flower of a plant secrets a surgery substance into its lower part B which goes towards the bottom part C of the flask-shaped organ. When a tiny grain D coming from the top part E of another reproductive organ Y i the flower falls on part A, it grows a long tube F through the organ X i response to the sugary substance and reaches the bottom part C of flask-shaped organ to carry out fertilisation.
(a) Name parts (i) organ X, and (ii) organ Y, inside the flower?
(b) Name parts (i) A (ii) B, and (iii) C, of flask-shaped organ.
(c) Name (i) grain D, and (ii) part E of organ Y.
(d) Name the tube F.
(e) What is the phenomenon of growing a long tube in response to sugary substance in the process of fertilisation in a flower known as?
When the leaves of a sensitive plant are touched with a finger, they fold up and when light fades at dusk, the petals of a dandelion flower close.
state two ways in which the above two processes differ.
Give an example for the movement of plant part which is very quick and can be observed easily.
List two differences between the movement of leaves of a sensitive plant and the movement of a shoot towards light.
Differentiate between:
Positive and negative tropism
