Ch 38- Plant Nutrition. By:Team GS. Nitrogen Fixation. A process performed by certain bacteria found in the nodules of leguminous plants, which make the resulting nitrogenous compounds available to their host plants.
Ch 38- Plant Nutrition
A process performed by certain bacteria found in the nodules of leguminous plants, which make the resulting nitrogenous compounds available to their host plants.
Important because plants need ammonia to build amino acids, but most of the nitrogen in the atmosphere is in the form of Nitrogen gas
Most plants lack the biochemical pathways (which includes the enzyme nitrogenase) necessary to convert nitrogen gas to ammonia
A root hair of Alfalfa is invaded by Rhizobium
Bacteria have the capacity to convert nitrogen gas to ammonia live close to plant roots. Others are located in plant tissues called nodules
Hosting these bacteria costs the plant to lose energy
To conserve energy, legume root hairs will not respond to bacterial signals when nitrogen levels are high
Extensive signaling between bacteria and the legume lets each organism know the other is present and checks whether the bacteria is the correct species for the specific legume
These highly evolved symbiotic relationships depend on exact species matches
Different legumes have their own specific symbiotic Rhizobium
This is called a saprophyte because it lacks chlorophyll and depends completely on decaying organic matter for all its nutrients. Indian pipes are found in forests of the northeastern United States