Temperature, photoperiod and irradiance on growth of Gracilaria salicornia (Gracilariales, Rhodophyta), in vitro

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 %.