b) Three commercial brown seaweed extract fertilizers or biostimulant:
Acadian marine plant extract powder (AMPEP),
GF600 (GF), and Gofar natural seaweed extract (NSE) were
tested individually at different concentrations of 5, 10, and
15 mg L−1 in optimized PES medium. Culture medium without
fertilizer/biostimulant was used as the control. Optimized concentration
of the selected fertilizer/biostimulant was then used
for the next parameter optimization study.