List of Articles irradiance

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  1 - The effect of continuous illumination and photoperiods on growth and heterocyst frequency of cyanobacterium Fischerella ambigua from Golestan province
  Fereshte Vakili Kayvan Ghorchibeigi Neda Soltani Shadman Shokravi
  10.30495/iper.2006.690227
  The effect of limited continuous irradiance and photoperiods on survival, growth and heterocyst frequencies of cyanobacterium Fischerella ambigua collected from paddy-fields of Golestan province have been studied at laboratory condition. After soil collection and cultur More

  The effect of limited continuous irradiance and photoperiods on survival, growth and heterocyst frequencies of cyanobacterium Fischerella ambigua collected from paddy-fields of Golestan province have been studied at laboratory condition. After soil collection and culture, sample were isolated, purified, and incubated under 2μEm-2s-1 continuous irradiance with no carbon dioxide addition. The photoperiods were 2, 4, 6, 8 hours darkness each day. Survival, growth and heterocyst frequencies were studied in each treatment using optical density and chlorophyll measurements. Results showed that this cyanobacterium can survive under relatively short times of darkness (2 and possibly 4hours). The highest specific growth rate was related to 2hours dankness daily. 6 and 8hours darknesses cause relative similar results. 8hours darkness daily showed the highest degree of stress and cause sharp drop in growth. Chlorophyll production and morphological behaviors of aggregations showed unpredictable irregular fluctuations independent of photoperiods. We saw highest amount of heterocyst frequency and better regular patterns of heterocyst production at continuous irradiance but correlation between growth and heterocyst production differ completely at this condition. Manuscript profile
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  2 - The effect of acidity at limited irradiance on survival, growth, pigment composition and ammonium liberation of soil cyanobacterium Nostoc sp., collected from paddy-fields of Golestan province
  فریبا Amirlatifi sh Shokravi مریم Safaei زهرا Hosseini kolbadi
  Cyanobacterium Nostoc sp. can be considered as an interesting microorganism for the ability of excretion buffering compounds. With respect to possible applied potential of this strain, this ability has been studied under limited irradiance. Soil samples were collected f More

  Cyanobacterium Nostoc sp. can be considered as an interesting microorganism for the ability of excretion buffering compounds. With respect to possible applied potential of this strain, this ability has been studied under limited irradiance. Soil samples were collected from paddy-fields during one year. At the first step, different acidities (pHs 5,7,9) were studied under limited carbon dioxide condition. Results showed that in all treatments, organism tends to enter logarithmic phase of growth until third day, but acidic condition cause sharp decline on growth after this. Highest specific growth rate belong to alkaline condition (pH 9). For the next step, two alkaline condition near to pH 9 (pHs 8.5 and 9.5), were selected to compare. Results showed that specific growth rate was significantly less than pH 9, and even continuous aeration couldn’t be able to enlarge specific growth rate. Pigment composition can be rearranged at different acidities and phycobilisome systems cause viability and growth under acidity fluctuations and limited irradiance in addition of low carbon dioxide concentration. Ammonium liberation showed the highest rate at pH 5 and day two too. Manuscript profile
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  3 - Growth of Sargassum boveanum (Fucales, Phaeophyta) under variations of temperature, photoperiod and irradiance in laboratory conditions
  F. Rafiee A. Esmaieli H. Kermanshahi
  Sargassum is one of the main sources of alginate, the substance with many commercial uses. The species Sargassum boveanum is an edible algae and study of effect of environmental factors on its growth is a step towards is culture. Therefore, growth of Sargassum boveanum More

  Sargassum is one of the main sources of alginate, the substance with many commercial uses. The species Sargassum boveanum is an edible algae and study of effect of environmental factors on its growth is a step towards is culture. Therefore, growth of Sargassum boveanum under various temperature, irradiance and photoperiod was studied over 6 weeks under laboratory condition. The macroalgae was collected from coasts of Lengeh in June 2011. For each treatment, the algae were inoculated into 20 liters of water aquariums with diameters of 60×30×40 cm. The suspension method used for culture of algae. .The culture conducted at 4700 lux for irradiance, 25Co for temperature ,35PPT for salinity and 12:12 hour (light: dark) photoperiod. The treatments were: temperature (15, 20 and 25oC), photoperiod (12:12, 14:10 and 16:8, light: dark, respectively) and photon irradiances (4700, 5700, 6700 lux). All treatments (tanks) were carried out in triplicates. The length and weight of the thalli were measured on 7, 14, 21, 28, 35 and 42 days. The results of this study showed significant differences on growth of S. boveanum between treatments. Maximum relative growth rate was obtained at 12:12 hour photoperiod (% 4/32), 25Co (% 2.68) and 4700 lux (% 4.32) that proved to be suitable for indoor culture. We recommend spring as the best season for mariculture this alga. Manuscript profile
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  4 - Temperature, photoperiod and irradiance on growth of Gracilaria salicornia (Gracilariales, Rhodophyta), in vitro
  F. Rafeei P. Nejatkhah Manavi H. Kermanshshi M. Parvaresh
  The green alge Gracilaria salicornia was collected from coasts of Gheshm Island in Persian Gulf in September 2010.The effect of temperature, photoperiod and irradiance on growth of Gracilaria salicornia were carried out over 6 weeks under laboratory conditions.  Fo More

  The green alge Gracilaria salicornia was collected from coasts of Gheshm Island in Persian Gulf in September 2010.The effect of temperature, photoperiod and irradiance on growth of Gracilaria salicornia were carried out over 6 weeks under laboratory conditions.  For each treatment, the algae were inoculated into 20 litre water with diameters of 60×30×40 cm. The suspension method used for culture .All treatments (tanks) were carried out in triplicates. The treatments were temperatures (20, 25 and 30oC), photoperiods (12:12, 14:12 and 16:8, light: dark, respectively) and photon irradiances (24, 66 and 94                         photons m-2 S-1).  The length, width and weight of the thalli were measured on 7, 14, 21, 28, 35 and 42 days. The results of this study showed significant differences on growth of G.salicornia between treatments (P<0.05). Maximum relative growth rate was obtained from 12:12 photoperiod with 2.46 %. Manuscript profile
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  5 - Perturb and Observe Maximum Power Point Tracking Method Based on Estimation of Irradiation Change by Independent Component Analysis
  Sonya Nodehi Mazdak Teimoortashloo
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