Gibberellic acid and 2,4-D as growth regulators in laboratory culture of seaweeds

Abstract

The growth regulatory effects of gibberellic acid (GA) and 2,4-D (2,4-dichlorophenoxy acetic acid) on a green alga, Ulva fasciata and two species of red algae, Gracilaria corlicata and Hypnea valentiae were studied. For a culture period of 30 days, the thallus segments showed varying growth rates on pretreatment with 6 to 20 mg/1 of the above growth substances. These compounds stimulated growth and increased wet weight o f the algae. At higher concentrations (16-20mg/l) 2,4-D was growth inhibitory, whereas, GA showed significantly higher growth at 16-20mg/l concentrations. It is concluded with the present study that plant hormones like GA and 2,4-D could be used for enhancement o f algal production in culture practices at different concentrations.