Vessel Volume, Gelling Agent, and Basal Salts Affect pH and Gel Strength of Autoclave Tissue Culture Media

Effects of autoclaving volume, gelling agent (Bactoagar, Gel-gro, Phytagar), and basal salts [Murashige and Skoog (MS); Woody Plant Medium (WPM); Gamborg BS (GB)] on gel strength and pH of tissue culture media were tested. Gel strength was significantly affected by gelling agent and basal medium. MS media were generally softer than comparable WPM or GB media. As the vessel volume during autoclaving decreased, gel strength significantly decreased with Phytagar and Bactoagar gelling agents; Gel-gro had greater gel strength at the intermediate volume of medium autoclaved. In all cases, autoclaving resulted in a pH decrease of 0.2 to 0.5 pH units [...]