EASY
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Earn 100
A young dicot seedling (e.g., soyabean) is laid horizontally on a surface and is subjected to gravity stimulus. The shoot bends in upward direction and the root bends in downward direction. Which out of the following is the possible reason for this movement?
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Important Questions on Plant Growth and Development
MEDIUM
NEET
IMPORTANT
Seed germination is the sprouting of a seed and growth of the embryo present inside the seed into a seedling or young plant capable of independent existence. Refer to the given figure showing seed germination and mark the incorrect option.
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Charles Darwin and his son, Francis experimented with phototropism of grass seedlings by placing a metal foil blindfold over different parts of the seedling's coleoptile. A simplified version of their results is shown below. Which of the following statements best explains their results?
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IMPORTANT
| I | II | ||
|---|---|---|---|
| Natural auxin | NAA | ||
| Synthetic auxin | Zeatin | ||
| Bakane disease of rice | IAA | ||
| Natural cytokinin | GA | ||
| Kinetin |
MEDIUM
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IMPORTANT
(i) Hormone induces flowering in mango and also promotes rapid internode/petiole elongation in deep water rice plants and hence helping leaves or upper part of shoot to remain above water.
(ii) Hormone promotes root growth and root hair formation.
(iii) Hormone inhibits the seed germination, increases the tolerance of plant to various stresses, play important role in seed development, maturation and dormancy.
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(i) Horizontal growth of seedlings, swelling of the axis and apical hook formation in dicot seedlings.
(ii) Promoting senescence and abscission of leaves and flowers.
(iii) Breaking seed and bud dormancy.
(iv) Initiating germination in peanut seeds.
(v) Sprouting of potato tubers.
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Statement 1: Ethylene is a gaseous hormone.
Statement 2: Ethylene causes climacteric ripening of fruits.
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| I (Phytohormone) |
II (Plant part where it is synthesised) |
||
|---|---|---|---|
| IAA | Tissues undergoing senescence | ||
| Cytokinins | Shoot apices | ||
| Ethylene | Root apices |
