Showing 3 results for Cyanobacteria
Volume 9, Issue 3 (10-2010)
Abstract
A study of flora and population changes in a sample paddy field in Kalat (Mashhad) were done from May to September 2007 in four stages. Physical and chemical factors such as EC, pH and temperature were measured. Totally, 23 species, 8 genera and 5 families were identified. The identified species were: Chroococcaceae: Chroococcus, Gloeothece, Aphanothece Oscillatoriaceae: Oscillatoria Rivulariaceae: Calothrix Nostocaceae: Cylindrospermum, Nostoc, Anabaena Scytonemataceae: Scytonema. Regarding the heterocystous species, the most abundant cyanobacteria belong to genus Nostoc. pH in 4 collection were alkaline and did not show significant difference. Colony number did not indicate direct relation with pH despite of EC. Maximum colony number was seen in minimum temperature.
Volume 18, Issue 47 (4-2007)
Abstract
Cyanobacteria is a big group of monera kingdom, that high potential for product some natural product, such as nutritional, pharmacologic material and etc. Oscillatoria is a kind of filamentous cyanobacteria. This microorganism observed in Tyab – bay in all of seasons. Seawater medium (SWM) is the best media for isolation of Oscillatoria from natural environment. Enriched SWM with B12 and semi-solid Z8 medium (0/7% agarose) is too suitable for purification of condense culture. Maximum coefficient (µ) was in valance medium. Purification of Oscillatoria has down at during nine mounths. Oscillatoria was exposed to five treatments of light /dark periods and six different temperatures. Results obtained revealed that among the employed 30°С treatment has had the best effect on increase maximum coefficient (µ=0.602) and also another treatment among the employed 14/10 (light / dark) hours (µ =0.506). In this treatment temperature was 25 °С.
Volume 18, Issue 56 (9-2006)
Abstract
Due to the importance of benthic cyanobacteria in nitrogen fixation in paddyfields, the physiological responses of Fischerella ambigua FS 18 to salinity (NaCl 0, 0.5 & 1%) were investigated. Results indicated that growth rate was higher in control and that NaCl did not inhibit growth of other treatments. Similar responses were seen in the case of other physiological processes. Chlorophyll was declined with increasing salinity. Phycobiliproteins (PBP), phycocyanin (PC) and allophycocyanin (APC) were at least in 0.5% but the differences were not significant. The light-saturated photosynthetic rate was higher in control and decreased with increasing in salinity. With respect to nitrogenase activity, the highest rate was in control and the cultures with higher growth rates reached to the maximum level at a shorter time. There was no significant difference between 0.5 and 1% in relation to nitrogenase activity.
