Indicate the response to each condition by drawing a straight seedling or one with the triple response.

Verified step by step guidance

1. Understand the concept of the 'triple response' in plants, which is a growth pattern observed in seedlings when exposed to ethylene. This response includes inhibition of stem elongation, thickening of the stem, and horizontal growth.
2. Identify the conditions that lead to the triple response. Typically, this occurs when a seedling encounters an obstacle, such as soil or a rock, which triggers the production of ethylene.
3. Draw a straight seedling to represent normal growth conditions without the presence of ethylene. This seedling should have a long, thin stem growing vertically.
4. Draw a seedling exhibiting the triple response. This should include a short, thickened stem with a horizontal or curved growth pattern, indicating the presence of ethylene.
5. Label each drawing clearly to indicate which one represents normal growth and which one represents the triple response, ensuring that the differences in growth patterns are easily distinguishable.

Key Concepts

Triple Response in Plants

The triple response in plants is a growth adaptation mechanism triggered by the plant hormone ethylene. It involves three key changes: inhibition of stem elongation, thickening of the stem, and horizontal growth. This response helps seedlings navigate through soil by altering their growth pattern to avoid obstacles.

Ethylene Hormone

Ethylene is a gaseous plant hormone that regulates various aspects of growth and development, including fruit ripening, leaf abscission, and stress responses. In seedlings, ethylene is crucial for the triple response, allowing them to adapt their growth in response to environmental challenges.

Seedling Growth Patterns

Seedling growth patterns refer to the ways in which young plants develop, typically characterized by vertical elongation towards light. However, under certain conditions, such as the presence of ethylene, seedlings may exhibit altered growth patterns like the triple response, which helps them overcome physical barriers in their environment.