In the symbiotic relationship between Rhizobium and the roots of leguminous plants, Rhizobium provides [[1]] to the plants whereas the plant gives [[2]] and shelter to the Rhizobium bacteria.

The symbiotic relationship between Rhizobium and the roots of leguminous plants is a mutualistic one, where both organisms benefit. 

Rhizobium is a type of nitrogen-fixing bacteria that lives in nodules on the roots of leguminous plants. 

These bacteria convert atmospheric nitrogen into a form that the plant can use, in exchange for carbohydrates that the plant produces during photosynthesis. 

Nitrogen is essential for the growth of the plant, and the plant provides a suitable environment and nutrients for the bacteria to thrive.