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Zorluk: ZorGrowth, Development, and Metamorphosis

Arrange the following physiological and biochemical events during seed germination in the correct chronological order from the onset of germination to the protrusion of the embryonic axis.

  1. 1Imbibition of water resulting in hydration and swelling of embryonic tissues
  2. 2Synthesis and release of gibberellins by the embryo
  3. 3Transcription and synthesis of hydrolytic enzymes (such as alpha-amylase) in the aleurone layer
  4. 4Enzymatic hydrolysis of stored starch into soluble reducing sugars
  5. 5Cell elongation and emergence of the radicle through the seed coat

Cevap

The correct chronological sequence is: Imbibition of water resulting in hydration -> Synthesis and release of gibberellins -> Transcription and synthesis of hydrolytic enzymes -> Enzymatic hydrolysis of stored starch -> Cell elongation and emergence of the radicle.
Seed germination begins physically with water imbibition. Hydration triggers the embryo to synthesize gibberellin hormones, which diffuse to the aleurone layer. The aleurone layer then synthesizes hydrolytic enzymes (such as alpha-amylase) that breakdown insoluble endosperm starch into soluble glucose. Finally, the embryo utilizes this glucose for respiration and growth, causing radicle elongation and emergence through the seed coat.

Adım Adım Çözüm

1
Identify the initial physical trigger of germination.
Water imbibition hydrates the seed coat and embryonic tissues.
Dormant seeds have low water potential and must absorb water to reactivate metabolic functions.
2
Trace the hormone signalling pathway initiated by hydration.
The activated embryo synthesizes and secretes gibberellins.
Gibberellins act as the biochemical signal instructing storage tissues to mobilize nutrients.
3
Determine the site of action for gibberellins.
Gibberellins bind to aleurone layer cells to induce production of hydrolytic enzymes like alpha-amylase.
Hydrolytic enzymes are synthesized de novo in response to gibberellin signals.
4
Identify the enzymatic digestion stage.
Insoluble starch in the endosperm is converted into soluble glucose.
Enzymes break down complex macromolecules into transportable molecules.
5
Identify the structural outgrowth stage resulting from nutrient utilization.
The radicle elongates and ruptures the seed coat.
Soluble sugars provide energy and building blocks for cell expansion at the radicle tip.

Anahtar Kavram

Physiological and Biochemical Sequence of Seed Germination
Tahmini Süre:2m 0s
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Konular

Growth, Development, and Metamorphosis

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