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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.

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Targets:The objective of this study was to control the reproductive cycle and increasing the efficiency of the production of pikeperch (Sander lucioperca) through determining the effects of different photoperiods on reproductive performance and egg and larval quality.
Methods: Pikeperch broodstock with mean weights 1367 ± 55.3 g were exposed to three different photoperiods with light intensity 630 lux including constant light (24L), constant darkness (24D), and 12 h of light, 12 h of darkness (12L:12D) with three replicates for 40 days.
Results: The results showed that the pikeperch reproductive performance was affected by photoperiod. Broodstock under 24L spawned earlier than those of the other photoperiods. The highest spawning were observed in the morning in 24L (66.7 ± 3.5%) and the lowest spawning belonged to the 24D and 12L:12D that never spawned at night. Although fertilization rate and number of eggs per gram  did not show any significant difference in various photoperiods, the timing of spawning and the egg quality exhibited remarkable difference.
Conclusion: The results of this study pointed out to effective application of photoperiod on changing the spawning time, reproductive and induction of out-of-season spawning of pikeperch broodstock. Additionally, these results unequivocally prove that the reproductive performance of pikeperch can be considerably improved and stimulated by an effective photoperiod.

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The alternative use of non-selective herbicides in different years will reduce the possibility of weeds resistance to herbicide by avoiding the crops constant exposure to herbicide selection pressure. The photoperiod-sensitive genic male sterile (PGMS) rice with herbicide resistance will be convenient to the mechanization of hybrid seed production and weed control. In order to develop double herbicide tolerant transgenic PGMS rice, the optimized Epspsgene and the Bar gene were jointly introduced into 7001S, a japonica PGMS rice, by Agrobacterium-mediated transformation. The coding sequence of Epsps gene was optimized based on the codon usage of rice genes and the function of optimized Epspsgene was validated by real-time PCR analysis, enzyme-linked immunosorbent assay of EPSPS protein, and herbicide resistant assay in the obtained independent transformants. The highest relative expression level of EPSPS protein in leaf reached 9.02% of the total soluble proteins. The transformants of T₂ generation withstood at least 3.332 g glyphosate /m² at seedling stage, which was 2.7 times higher than that reported by Monsanto Company. The transformants harboring the optimized Epsps gene and Bar gene were also resistant to glyphosate and glufosinate simultaneously at seedling stage; the resistant dosages were 0.375 g glufosinate m^-2 and 0.833 g glyphosate m^-2.