AZOLLA - A REVIEW OF ITS BIOLOGY AND UTILIZATION

The Azolla-Anabaena symbiosis is outstanding due to its high productiv ity combined with its ability to fix nitrogen at high rates. Because o f this, in recent decades, countless studies have been conducted on th is association, but with insufficient synthesis and coordination. This paper, therefore, attempts to review and synthesize past and recent f indings concerning the biology and utilization of Azolla in hopes that this will facilitate increased future collaborative research on this ''green gold mine.'' It reviews the taxonomy,distribution, morphology, physiology, and reproduction of Azolla as well as new developments in its manifold uses. Because of the growing concern about conservation of the environment and the need for deploying renewable, sustainable r esources; the application of Azolla as a biofertilizer on agricultural crops, in order to provide a natural source of the crucial nutrient n itrogen, can be very beneficial to the future of our planet. Besides t he environmental appropriateness of the use of Azolla, for multitudes of farmers in many parts of the world who cannot afford chemical ferti lizers, Azolla application can enhance their economic status, increasi ng yields while minimizing costs. Due to the fact that rice paddy fiel ds form an ideal environment for Azolla, one of its most suitable appl ications is on rice. Besides its utilization as a biofertilizer on a v ariety of crops, Azolla can be used as an animal feed, a human food, a medicine, and a water purifier. It may also be used for the productio n of hydrogen fuel, the production of biogas, the control of weeds, th e control of mosquitoes, and the reduction of ammonia volatilization w hich accompanies the application of chemical nitrogen fertilizer.