Bacteria; Cyanobacteria, Nostocales, Nostocaceae, Anabaena, Species: Azollae Description and significance Anabaena Azollae is a small filamentous phototrophic cyanobacteria generally seen as a multicellular organism with two distinct, interdependent cell types. The second is a heterocyst; a larger, paler, more homogenous cell produced by Anabaena to fix atmospheric nitrogen. Azolla also known as mosquito fern, duckweed fern, or fairy moss is a genus of common waterfern whose small leaves accumulate on the surface of bodies of water creating mats. Azollae and Azolla have formed a symbiotic relationship in which the cyanobacterium receives carbon and nitrogen sources from the plant in exchange for fixed nitrogen. This relationship has proven to be useful to humans in the production of food; specifically in the fertilization of rice paddies. Azolla is used as an organic biofertilizer to increase the nitrogen levels in the rice paddies.

Author:Tagor Voodoogrel
Language:English (Spanish)
Genre:Personal Growth
Published (Last):8 October 2016
PDF File Size:20.71 Mb
ePub File Size:5.32 Mb
Price:Free* [*Free Regsitration Required]

Fiksasi nitrogen oleh Anabaena[ sunting sunting sumber ] Di bawah kondisi nitrogen terbatas, sel vegetatif berdiferensiasi menjadi heterokista pada interval semiregular di sepanjang filamen. Sel-sel heterokista secara khusus terbatas untuk fiksasi nitrogen.

Bagian dalam sel-sel ini adalah mikro-oksik sebagai hasil dari peningkatan respirasi, inaktivasi fotosistem PS II yang menghasilkan O2, dan pembentukan selubung tebal di luar dinding sel. Nitrogenase dalam sel-sel ini mengubah dinitrogen menjadi amonium dengan mengorbankan ATP dan reduktan—keduanya dihasilkan oleh metabolisme karbohidrat, proses yang ditambah, ketika ada cahaya, oleh aktivitas PS I. Karbohidrat, mungkin dalam bentuk glukosa, disintesis dalam sel vegetatif dan bergerak ke heterosista.

Sebagai imbalannya, nitrogen terfiksasi dalam heterosista bergerak ke sel vegetatif, setidaknya sebagian dalam bentuk asam amino.

Proses di mana cahaya mengubah bentuk molekul di retina , sehingga mendorong reaksi seluler dan sinyal yang menyebabkan penglihatan pada vertebrata , dipelajari di Anabaena. Rhodopsin sensoris Anabaena, protein membran peka cahaya spesifik, merupakan pusat dari penelitian ini.

Biochimica et Biophysica Acta. Diakses tanggal European Journal of Phycology.


Anabaena azollae

Selected References These references are in PubMed. This may not be the complete list of references from this article. Tandeau de Marsac N. Occurrence and nature of chromatic adaptation in cyanobacteria. J Bacteriol.


Heterocyst cells are terminally specialized for nitrogen fixation. The interior of these cells is micro-oxic as a result of increased respiration, inactivation of O2-producing photosystem PS II, and formation of a thickened envelope outside of the cell wall. Nitrogenase , sequestered within these cells, transforms dinitrogen into ammonium at the expense of ATP and reductant—both generated by carbohydrate metabolism, a process supplemented, in the light, by the activity of PS I. Carbohydrate, probably in the form of glucose, is synthesized in vegetative cells and moves into heterocysts. In return, nitrogen fixed in heterocysts moves into the vegetative cells, at least in part in the form of amino acids. This has led to the plant being dubbed a "super-plant", as it can readily colonise areas of freshwater, and grow at great speed - doubling its biomass in as little as 1.

Related Articles