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प्रश्न
The role of ethylene and abscisic acid is both positive and negative. Justify the statement.
उत्तर
Positive roles of ethylene: Influences of ethylene on plants include horizontal growth of seedlings, swelling of the axis and apical hook formation in dicot seedlings. Ethylene breaks seed and bud dormancy, initiates germination in peanut seeds and sprouting of potato tubers.
- Negative roles of ethylene: Ethylene promotes senescence and abscission of plant organs especially leaves and flowers.
- Positive roles of abscisic acid: ABA plays an important role in seed development and maturation.
- Negative roles of abscisic acid: It acts as a general plant growth inhibitor and an inhibitor of plant metabolism. ABA inhibits seed germination. ABA stimulates the closure of stomata in the epidermis and increases the tolerance of plants to various kinds of stresses.
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संबंधित प्रश्न
Define parthenocarpy.
How many meiotic divisions are required to produce 200 seeds?
Name the following :
The layer of the endosperm of maize rich in protein.
Differentiate between germination and vivipary.
With regard to germination in bean seed, answer the following question:
Draw a neat labelled diagram of the structure named above.
The three conditions necessary for germination of seeds are (tick the correct answer):
Give the main difference between hypogeal and epigeal and germination.
Explain the following term:
Hypogeal germination
Explain the following term:
Epigeal germination
A seed is provided with all the conditions necessary for germination. Yet it fails to germinate. Explain.
______ is a non-endospermic seed.
Identify the character of angiosperms that helped in their dominance on earth.
From which of the following a true fruit is developed?
______ refers to persistent nucellus in the seed.
Dicotyledons have seeds with ______ cotyledons.
Sketch and label maize seed.
