Directions: Use the information provided and your knowledge of Life Science to answer the following questions. Show all work where necessary.
Directions: Use the information provided and your knowledge of Life Science to answer the following questions. Show all work where necessary.
In hydroponics, plants are grown without soil - their roots are placed in water enriched with minerals and exposed to air that contains carbon dioxide. Farmers and scientists have used this method to grow vegetables, herbs, and even fruit trees successfully.
Researchers from the University of Arizona Controlled Environment Agriculture Center grew lettuce plants under two conditions:
In soil pots watered normally.
In hydroponic systems with water and nutrients, but no soil.
Both groups received the same light, air, and water.
Growth Condition | Average Plant Height (cm) | Leaf Count | Dry Mass (g) | Water Used (L) |
|---|---|---|---|---|
Soil | 22.5 | 16 | 14.2 | 5.8 |
Hydroponic | 25.8 | 19 | 16.4 | 5.9 |
Plants grown hydroponically (in water) grew as well as or better than plants in soil. Because no soil was present, the increase in mass must have come from carbon dioxide from the air and water used during photosynthesis. Nutrients dissolved in the water support growth, but the main mass - the carbon structure of the plant - comes from air and water.
This modern agricultural method gives strong evidence that plants don’t “eat” soil - they build their mass from air (
Explain how hydroponic plant growth supports the idea that plants get their mass from air and water, not soil.
Write your response using Claim, Evidence, and Reasoning.
Based on Table 1, what differences are seen between soil-grown and hydroponic plants?
Use data to support your answer.
Which materials provide most of the carbon that becomes plant mass?
Which observation best supports the idea that soil is not required for plants to grow?
Explain how photosynthesis allows hydroponic plants to grow even though they are not in soil.