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Zorluk: OrtaGrowth, Development, and Metamorphosis

A student set up an experiment to observe hypogeal germination in a maize seed (*Zea mays*). In which chronological sequence do the following physiological and morphological events occur during this growth process?

  1. 1Imbibition of water through the micropyle, leading to hydration of tissue and enzyme activation.
  2. 2Emergence of the radicle through the ruptured seed coat to grow downwards into the soil.
  3. 3Rapid elongation of the epicotyl, pushing the plumule upward while the cotyledon remains subterranean.
  4. 4Rupture of the protective coleoptile by the expanding green foliage leaves upon exposure to light.

Cevap

The correct developmental sequence for hypogeal germination is: (1) Imbibition of water through the micropyle, (2) Emergence of the radicle growing downwards, (3) Rapid elongation of the epicotyl pushing the plumule upward, and (4) Rupture of the protective coleoptile by expanding foliage leaves.
Germination starts with water imbibition via the micropyle, activating metabolic enzymes. The radicle emerges first to establish root anchorage and water uptake. Following this, epicotyl elongation pushes the protective coleoptile and plumule upward through the soil. Finally, exposure to light stimulates the first foliage leaves to rupture the coleoptile and unroll for photosynthesis.

Adım Adım Çözüm

1
Identify the initial physical trigger required for seed metabolism.
Water imbibition occurs first, swelling the endosperm and activating digestive enzymes.
Metabolic processes and cell expansion cannot take place in dry seed tissues.
2
Determine the first embryonic organ to pierce the seed coat.
The radicle emerges downwards into the soil to form the primary root system.
Anchorage and water absorption are necessary before shoot growth commences.
3
Analyze shoot elongation specific to hypogeal germination.
The epicotyl elongates, carrying the sheath-enclosed plumule upward while the cotyledon stays below ground.
Hypocotyl growth is minimal in hypogeal germination, keeping the food storage organ underground.
4
Identify the final step in establishing autotrophic seedling growth.
Foliage leaves break out of the coleoptile upon reaching light and expand to photosynthesize.
This completes seedling development and transitions the plant to independent energy production.

Anahtar Kavram

Sequence of events in hypogeal seed germination
Tahmini Süre:1m 30s
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Konular

Growth, Development, and Metamorphosis

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