Which type of plant is known for symbiotic nitrogen fixation in its root nodules?

Legumes are distinguished by their ability to engage in symbiotic nitrogen fixation within their root nodules, which is a vital ecological process. This characteristic is attributed to their association with specific bacteria, primarily from the genus Rhizobium. These bacteria reside in nodules formed on the roots and convert atmospheric nitrogen into ammonia through a process known as nitrogen fixation. This ammonia is then utilized by the legumes for growth, creating a reciprocal relationship where the plants provide carbohydrates to the bacteria.

This ability to fix nitrogen enriches the soil, making legumes important for crop rotations and sustainable farming practices, as they can enhance soil fertility without the need for synthetic fertilizers. The other plant types listed do not exhibit this specific symbiotic relationship. Grasses typically have different forms of root systems without this nitrogen-fixing capability, while ferns and succulents also lack the root nodules required for this process. Therefore, legumes are recognized as the group of plants most prominently associated with nitrogen fixation.