Ramin Sharafi, Omidvar Farhadian, Mohsen Soleimani,
Volume 3, Issue 1 (6-2014)
Abstract
The effect of six diets including Scenedesmus quadricauda), manure (cattle+poultry, 1:1 ratio), vegetable (spinach+parsely+coriander, 1:1:1 ratio), algae+soil, vegetable+soil, and manure+soil were examined on culture of freshwater copepod, Acanthocyclopsrobustus, under the experimental conditions of 23±1ºC, 12 hours dark: 12 hours light photoperiod, and light intensity of 60 µmol photons/m2/s. The maximum population density (1282.6±163.7 individuals/L), maximum specific growth rate (SGR) (0.17±0.0 /day) and minimum doubling time (Dt) (4.0±0.1 days) were obtained when A. robustus fed on algae+soil. The nauplii production was 727.3±42.4 (±SE), 272.0±23.5, 267.6±17.7, 147.0±18.2, 33.6±3.8 and 25.0±7.1 ind./L and copepodit production was 311.3±26.8, 124.3±11.1, 183.0±13.0, 59.0±7.1, 14.3±8.1, and 17.6±3.6 ind./L in algae, algae+soil, vegetable, vegetable+soil, manure+soil, and manure, respectively. Correspondingly, the adult production was 208.5±26.8, 51.6±16.5, 192.7±23.7, 91.7±28.4, 8.7±5.4 and 8.7±3.6 ind./L, respectively. The maximum body length (663.8±29.1 µm) and width (526.2±23.7 µm) of A. robustus were recorded when fed with vegetable+soil and vegetable, respectively. The number of nauplii, copepodit, adults, length and width were significantly correlated with EC, BOD and COD. According to results, the A. robustus has suitable potential culture on algal and non-algal diets based on production, growth, body size, BOD and COD, but the better performance obtain on algae+soil and vegetable.
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Volume 3, Issue 3 (12-2014)
Abstract
In a completely randomized design, the effects of heavy metals of Cd, Cu, Pb and Ni at concentrations of 0, 5, 50 and 100 mg/l on chlorophyll a and biomass in green algae Scenedesmus quadricauda were investigated for 14 days under laboratory conditions of 23 °C, 12 h light: 12 hours light and light intensity of 60 mol photons/m2/s. The lowest density, chlorophyll a and dry biomass obtained at 100 mg/l in all of the heavy metals. The mean (±SE) highest increasing rates of chlorophyll a were 24.2±1.1, 23.1±0.8, 36.7±1.4 and 35.5±1.2% for Cd, Cu, Pb and Ni, respectively. Correspondingly, the reduction rates based on dry biomass were 51.5±3.1, 35.2±1.1, 47.9±1.6 and 56.6±2.8% for Cd, Cu, Ni and Pb, respectively. The results showed that heavy metals made significant reduction on chlorophyll a and dry biomass in S. quadricauda.
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Volume 6, Issue 3 (12-2017)
Abstract
In this study, the combined effects of temperature and photoperiod on ascorbic acid of freshwater microalgae Scenedesmus quadricauda were investigated. The experiment was carried out at three photoperiods (8L:16D, 12L:12D and 16L:8D) and three temperatures (20, 25 and 30 °C) for 20 days as completely randomized design in 5-L Erlenmeyer flasks. Based on results, the acid ascorbic (AA) were significant differences among treatments (p<0.05). At 8th day of culture, the highest AA amount of 0.38±0.06% dry weight and 60.6±10.1 fg/cell were obtained at 16L:8D photoperiod at 30 °C. In addition, the lowest AA was 0.11±0.03% dry weight at 8L:16D photoperiod at 30 °C at 8th day of culture. The growth phases affect on the acid ascorbic at cultures. The AA at 16L:8D photoperiod at 30 °C at 8th day of culture (logarithmic phase) was more than that 20th day of culture (stationary phase). This study illustrated that increasing light hours improved and increasing temperature had not considerable effect on AA content among different treatments.
