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Soru

Zorluk: Çok zorGrowth, Development, and Metamorphosis

Match each developmental signal or growth mechanism on the left with its corresponding physiological outcome or developmental process on the right.

  • Ecdysone secretion in the presence of high juvenile hormone concentrationInitiation of larval-to-larval ecdysis maintaining juvenile structural features
  • Ecdysone secretion following the degeneration of the corpus allatum (low juvenile hormone)Induction of metamorphosis into pupal or adult stages
  • High ratio of auxin to cytokinin maintained at the shoot apexSuppression of lateral bud outgrowth (maintenance of apical dominance)
  • Rapid elongation of the hypocotyl during seed germinationElevation of cotyledons above the soil surface (epigeal germination)

Cevap

Ecdysone with high juvenile hormone pairs with larval-to-larval molting; ecdysone with low juvenile hormone pairs with metamorphosis; high auxin to cytokinin ratio pairs with apical dominance suppression of lateral buds; hypocotyl elongation pairs with epigeal germination elevating cotyledons above soil.
Growth and development in insects and plants are tightly regulated by hormonal concentrations and axial tissue elongation. Ecdysone induces molting; high juvenile hormone maintains larval traits, whereas its decline leads to metamorphosis. In plants, high apical auxin maintains apical dominance over axillary buds. In seed germination, hypocotyl elongation carries cotyledons above the surface in epigeal germination.

Adım Adım Çözüm

1
Analyze insect endocrine regulation of ecdysis and metamorphosis.
Ecdysone triggers cuticle shedding. High juvenile hormone preserves larval stage (larval-to-larval molt). Absence/low juvenile hormone allows ecdysone to induce pupation and metamorphosis.
Juvenile hormone acts as a status-quo hormone modifying the action of ecdysone.
2
Analyze plant hormonal control of meristematic activity.
Apical dominance is maintained when auxin concentrations from the apical bud are significantly higher relative to cytokinins.
Auxin inhibits lateral (axillary) bud growth directly or indirectly through hormonal signaling pathways.
3
Differentiate seedling germination biomechanics.
Hypocotyl growth below cotyledons raises them above the soil line (epigeal), whereas epicotyl growth leaves cotyledons below ground (hypogeal).
The site of maximal cellular elongation determines whether cotyledons are pushed upward or remain buried.

Anahtar Kavram

Hormonal control of growth, apical dominance, germination patterns, and insect metamorphosis
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Konular

Growth, Development, and Metamorphosis

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