In Other Species
Root nodules that occur on non-legume genera like Parasponia in association with Rhizobium bacteria, and those that arise from symbiotic interactions with Actinobacteria Frankia in some plant genera such as Alnus, vary significantly from those formed in the legume-rhizobia symbiosis. In these symbioses the bacteria are never released from the infection thread. Frankia nodulates approximately two hundred species in the following orders (families in parentheses): Cucurbitales (Coriariaceae and Datiscaceae), Fagales (Betulaceae, Casuarinaceae, and Myricaceae), Rosales (Rhamnaceae, Elaeagnaceae and Rosaceae). Actinorhizal symbioses account for roughly the same amount of nitrogen fixation as rhizobial symbioses.
Some fungi produce nodular structures known as tuberculate ectomycorrhizae on the roots of their plant hosts. Suillus tomentosus, for example, produces these structures with its plant host lodgepole pine (Pinus contorta var. latifolia). These structures have in turn been shown to host nitrogen fixing bacteria which contribute a significant amount of nitrogen and allow the pines to colonize nutrient-poor sites.
Read more about this topic: Root Nodule
Famous quotes containing the word species:
“If we consider the superiority of the human species, the size of its brain, its powers of thinking, language and organization, we can say this: were there the slightest possibility that another rival or superior species might appear, on earth or elsewhere, man would use every means at his disposal to destroy it.”
—Jean Baudrillard (b. 1929)