Question

1. describe each of the following tropisms: tropism geo/gravitropism hydrotropism phototropism thigmotropism definition copy and paste an image to remember the response 4. how does the response of a root to the pull of gravity help a plant? 5. consider plant roots and stems. which tropism affects both these plant tissues? which tropism versus which experiences positive tropisms versus negative tropisms? 6. based on your observations, do plants respond and change the way they grow depending on where the light is? which tropism is this?

Explanation:

Tropisms are directional growth - responses of plants to external stimuli. Geotropism (gravitropism) is growth in response to gravity, hydrotropism to water, phototropism to light, and thigmotropism to touch. Gravity helps roots grow downwards (positive geotropism) for stability and access to water and nutrients. Plant roots and stems can show different tropisms. Positive tropisms are growth towards a stimulus, negative away from it. For light, shoots often show positive phototropism and roots negative phototropism.

Answer:

3.

• Tropism: A directional growth - response of a plant to an external stimulus.
• Geotropism/gravitropism: The growth response of a plant to the gravitational force. Roots usually show positive geotropism (growing downwards) and shoots negative geotropism (growing upwards).
• Hydrotropism: The growth response of a plant towards water. Roots often grow towards water sources.
• Phototropism: The growth response of a plant to light. Shoots typically show positive phototropism (growing towards light) and roots negative phototropism.
• Thigmotropism: The growth response of a plant to touch or contact. For example, tendrils of climbing plants coil around supports.

1. The pull of gravity helps a root grow downwards (positive geotropism). This is important for the root to anchor the plant firmly in the soil and to access water and nutrients deeper in the ground.
2. Roots may show positive hydrotropism and negative phototropism, while stems may show positive phototropism. Positive tropisms are growth towards a stimulus (e.g., light for stems), and negative tropisms are growth away from a stimulus (e.g., light for roots).
3. If a plant's shoot grows towards light, it is positive phototropism. If a root grows away from light, it is negative phototropism. If a root grows towards water, it is positive hydrotropism. If a tendril coils around a support, it is positive thigmotropism.