Activated Charcoal — 100 g

Added to tissue culture media at 0.1–5 g/L to adsorb inhibitory phenolics, excess growth regulators, and toxic metabolites secreted by the explant. Essential for recalcitrant species, woody plants, orchids, and palms prone to phenolic browning (oxidative browning). Darkens the medium, reducing light exposure to roots. Important: activated charcoal also adsorbs PGRs — compensate by increasing growth regulator concentrations when charcoal is present.