Anabaena azollae

Azolla and the blue-green alga Anabaena azollae maintain a symbiotic relationship: the alga provides nitrogen to the fern, and the fern provides a habitat for the alga. This property of nitrogen fixation has made Azolla extremely important economically in the cultivation of rice, particularly in Asia. The species of the…

…live colonies of a cyanobacterium, Anabaena azollae. These photosynthetic bacteria have the ability to transform atmospheric nitrogen into nitrate fertilizer. When individual plants of Azolla die, this nitrate fertilizer is released into the environment, where it becomes available to other plants. In addition to its use in rice fields, Azolla…

…Asia; a blue-green algae (Anabaena azollae) is always found in pockets on the leaves of Azolla and helps convert nitrogen to a form usable by other plants (see nitrogen-fixation), thus greatly increasing the productivity of rice paddies where the fern occurs. The greatest economic value of ferns has been…