Book 24, Question 67
How do bean and pea roots get help from bacteria?
Plants need nitrogen to grow, and the air is full of it, but plants can't use it as a gas. Beans, peas, and clover have little lumps on their roots called nodules, filled with helpful bacteria. The bacteria change nitrogen from the air into a form the plant can use, and the plant gives them sugar. Farmers plant these crops to enrich the soil.
More fun facts
- About 80 percent of the air is nitrogen gas, but most living things can't use it.
- Bean and pea plants team up with soil bacteria called rhizobia.
- The bacteria move into the roots and live in small bumps called nodules.
- Inside the nodules, the bacteria turn nitrogen from the air into a form the plant can use.
- In return, the plant gives the bacteria food and energy.
- Nodules that are working turn pink or red inside.
Sources: NMSU
Questions kids ask
How soon do the nodules show up?
In a field, small nodules can be seen 2 to 3 weeks after planting.