Examples of Ethylene's Effects on Plant Growth and Development

📚 Quick Study Guide

• 🍎 Ethylene's Role: A gaseous plant hormone primarily involved in fruit ripening, senescence, and stress responses.
• 🌱 Production: Synthesized from methionine via ACC (1-aminocyclopropane-1-carboxylic acid).
• 💨 Diffusion: Being a gas, ethylene diffuses easily throughout the plant and even to neighboring plants.
• 🍌 Fruit Ripening: Triggers the breakdown of chlorophyll, cell wall degradation, and changes in flavor and texture.
• 🍁 Leaf Abscission: Promotes the formation of the abscission layer, leading to leaf fall.
• 🌷 Flower Senescence: Causes petal wilting and flower death.
• 🛡️ Stress Response: Induces defense mechanisms in response to wounding, flooding, or pathogen attack.
• 📈 Interactions: Ethylene interacts with other plant hormones like auxins and cytokinins to regulate development.

🧪 Practice Quiz

1. Which of the following is a primary effect of ethylene on fruit?
   1. A. Promotion of cell division
   2. B. Inhibition of ripening
   3. C. Degradation of chlorophyll
   4. D. Increased photosynthesis
2. Ethylene is synthesized from which amino acid precursor?
   1. A. Tryptophan
   2. B. Methionine
   3. C. Glycine
   4. D. Glutamine
3. What process does ethylene primarily regulate, leading to leaf drop in autumn?
   1. A. Apical dominance
   2. B. Leaf abscission
   3. C. Phototropism
   4. D. Gravitropism
4. How does ethylene typically affect flower petals?
   1. A. Promotes petal growth
   2. B. Inhibits petal coloration
   3. C. Causes petal wilting
   4. D. Prevents petal opening
5. Which of these environmental stresses can stimulate ethylene production in plants?
   1. A. Drought
   2. B. High light intensity
   3. C. Flooding
   4. D. Nutrient deficiency
6. Ethylene interacts with which other plant hormone to influence plant development?
   1. A. Gibberellin only
   2. B. Abscisic acid only
   3. C. Auxins and cytokinins
   4. D. Brassinosteroids only
7. What is the immediate precursor to ethylene?
   1. A. Indole-3-acetic acid (IAA)
   2. B. 1-aminocyclopropane-1-carboxylic acid (ACC)
   3. C. Zeatin
   4. D. Abscisic acid (ABA)