Ethylene

Definition

Ethylene is a colorless gas that acts as a plant hormone, influencing various growth and developmental processes in plants. It plays a key role in regulating responses to environmental stimuli, such as fruit ripening, flower wilting, and leaf abscission, helping plants adapt to their surroundings.

5 Must Know Facts For Your Next Test

1. Ethylene is produced in response to various environmental stresses such as drought, flooding, or mechanical damage, signaling the plant to initiate protective measures.
2. One of the most well-known effects of ethylene is its role in fruit ripening; it accelerates the ripening process in many fruits like bananas and tomatoes.
3. Ethylene influences leaf abscission, which is the shedding of leaves, helping the plant conserve resources during unfavorable conditions.
4. The presence of ethylene can also lead to flower wilting and senescence, signaling the plant to prepare for reproduction or conserve energy.
5. Ethylene functions through a signaling pathway that involves receptors on the cell surface, leading to changes in gene expression that trigger physiological responses.

Review Questions

• How does ethylene influence fruit ripening and what role does it play in plant adaptation?
  • Ethylene significantly accelerates the ripening process in many fruits by triggering biochemical changes that lead to color change, softening, and flavor development. This hormonal action is crucial for plants as it allows them to synchronize their reproductive strategies with environmental conditions, ensuring that fruits are ripe and ready for dispersal at the appropriate time. By facilitating this adaptation, ethylene helps plants optimize their chances of reproduction and survival.
• Discuss the relationship between ethylene and leaf abscission in plants under stress conditions.
  • Under stress conditions such as drought or nutrient deficiency, ethylene levels increase, leading to leaf abscission. This process allows plants to shed leaves that may be consuming valuable resources without contributing to photosynthesis. By losing these leaves, plants can conserve water and energy while redirecting their resources to surviving stressors. The regulation of this process through ethylene demonstrates how plants adapt their growth strategies in response to changing environments.
• Evaluate the importance of ethylene signaling pathways in plant responses to environmental stimuli compared to other hormones.
  • Ethylene signaling pathways are critical for mediating a variety of plant responses to environmental stimuli, particularly when compared to other hormones like auxins or gibberellins. While auxins are primarily involved in growth directionality and gibberellins stimulate growth processes like flowering and seed germination, ethylene is uniquely positioned as a regulator of stress responses and senescence. This makes ethylene essential for quick adaptations to adverse conditions, reflecting its role as a key hormone in maintaining plant homeostasis amidst fluctuating environmental factors.

Related terms

Abscisic Acid: A plant hormone that helps regulate stress responses, including drought tolerance and seed dormancy.

Auxins:

A class of plant hormones that promote cell elongation, growth, and development, particularly in response to light and gravity.

Gibberellins: Plant hormones that stimulate stem elongation, seed germination, and flowering processes.