Optimal conditions for tissue growth and branch induction of Gracilariopsis persica

The species gracilariopsis persica was first described by bellorin et al. (2008). g. persica grows from late september to july and shows high growth rate from january to may in the persian gulf. tissue growth and branch induction of red seaweed, gracilariopsis persica from the persian gulf investigated under various culture levels of temperature, light intensity, photoperiod, salinity, initial length, propagule density and chemical preservatives. optimal size of propagules used as seed was 2 cm and faster growth of tissue and branch induction obtained at lower density. the apical part of the g. persica showed as the starting point of growth. the g. persica showed optimal growth in pes medium at 24°c, 60?mol m-2 s-1 light intensity, 12l: 12d and salinity of 39‰. but maximum branch production occurred under condition of 24°c, 20 ?mol m-2 s-1 light intensity, photoperiod of 16l: 8d and salinity 39‰. addition of chemical preservatives of p-hydroxybenzoic acid and potassium sorbate in culture medium showed marginal suppression on tissue growth and branch induction, that suitable for preparation of semi-axenic culture condition.