Design an experiment to demonstrate hydrotropism.
Experiment to Demonstrate Hydrotropism
Hydrotropism is the directional growth movement of plant parts in response to water. Since 'hydro' means water, this tropism involves the growth of plant parts towards or away from water as a stimulus. Roots typically show positive hydrotropism by growing towards water sources.
Materials Required: A conical flask filled with water, wire mesh to cover the flask neck, two or three freshly germinated bean seeds, and a cardboard box.
Procedure: Cover the neck of the water-filled conical flask with wire mesh. Place the freshly germinated bean seeds on the wire mesh. The water in the flask creates a moist environment below the seeds. Keep this setup in a cardboard box to minimize other environmental stimuli. Observe the direction of root growth over two to three days.
Observation: The roots of the germinated bean seeds will grow downwards towards the water in the flask. This demonstrates that roots respond to water as a stimulus by growing towards it, showing positive hydrotropism.
Conclusion: This experiment demonstrates hydrotropism, where roots show directional growth towards water. This tropic movement ensures that roots can locate water sources essential for the plant's survival, similar to how shoots show phototropism by growing towards light.
Explanation
The answer defines hydrotropism based on the context's explanation that 'hydro' means water, and tropism refers to directional growth movements. The experimental setup adapts the methodology from Activity 6.2, using similar materials (conical flask, wire mesh, germinated bean seeds, cardboard box) but focusing on water as the stimulus. The context discusses tropic movements as directional growth towards or away from stimuli, and mentions that roots show tropism. The experiment demonstrates that roots exhibit positive hydrotropism by growing towards water sources.
Solution Steps
Step 1: Define hydrotropism as directional growth movement in response to water based on the context.
Step 2: List materials from Activity 6.2 framework - conical flask, water, wire mesh, germinated bean seeds, cardboard box.
Step 3: Describe procedure placing seeds on wire mesh above water source to create water stimulus.
Step 4: Observe root growth direction over 2-3 days.
Step 5: Conclude that roots show positive hydrotropism by growing towards water.