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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
How do auxins promote the growth of a tendril around a support?
What is a plant hormone? Name four plant hormones. State one function of each.
What happens to the dandelion flower
- during the daytime, and
- at night?
What is this phenomenon known as?
Plant roots grow downward in response to ______.
What is meant by ‘positive geotropism’ and ‘negative geotropism’? Give one example of each type. Draw a labelled diagram to illustrate your answer, indicating the plant part, which shows positive geotropism, and the plant part, which shows negative geotropism.
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?
Chlorophyll differs from hemoglobin by the presence of its central molecule ______.
Why do roots of halophytes show negative geotropism?
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.
Name the following:
The tropic movement of plant parts in response to chemicals.
