Alder root nodules
![root nodules](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/full_width/public/thumbnails/image/alder_root_nodules_1.jpg?itok=lx_VP0nJ)
Detailed Description
Root nodules are a symbiotic relationship between a plant and nitrogen-fixing bacteria. A symbiotic relationship is one where both organisms benefit. Nitrogen-fixing bacteria change inorganic nitrogen from the air into ammonia, a form of nitrogen most organisms can use. They also use a process called rock dissolution to release other nutrients, such as calcium and phosphorus, so plants and trees can use them.
Sources/Usage
Public Domain.