Final answer:
Leguminous plants form nodules on their roots where rhizobium bacteria reside and fix nitrogen. Leghemoglobin in nodules helps create oxygen-free conditions necessary for the nitrogenase enzyme to function, facilitating this symbiosis and promoting sustainable agriculture.
Step-by-step explanation:
Leguminous plants can provide a space free of oxygen for their symbiotic rhizobium bacteria, which require an oxygen-free environment to fix nitrogen effectively. The key to this process lies in the special structures called nodules, formed on the roots of leguminous plants. Within these nodules, the enzyme nitrogenase—which is responsible for the conversion of atmospheric nitrogen to ammonia—is protected from oxygen. This protection is achieved by a molecule called leghemoglobin, which sequesters oxygen, thus creating the anaerobic conditions necessary for the nitrogenase to function.
Through this symbiotic relationship, leguminous plants not only provide a favorable environment for rhizobia but also benefit from a natural source of fertilizer. This relationship highlights the significance of sustainable agriculture practices that minimize the use of synthetic chemicals and support soil health.