Hy. Wetzstein et al., VESSEL VOLUME, GELLING AGENT, AND BASAL SALTS AFFECT PH AND GEL STRENGTH OF AUTOCLAVED TISSUE-CULTURE MEDIA, HortScience, 29(6), 1994, pp. 683-685
Effects of autoclaving volume, gelling agent (Bactoagar, Gel-gro, Phyt
agar), and basal salts [Murashige and Skoog (MS); Woody Plant Medium (
WPM); Gamborg B5 (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 o
r GB media. As the vessel volume during autoclaving decreased, gel str
ength significantly decreased with Phytagar and Bactoagar gelling agen
ts; Gel-gro had greater gel strength at the intermediate volume of med
ium autoclaved. In all cases, autoclaving resulted in a pH decrease of
0.2 to 0.5 pH units. Lower pH values were associated with softer gels
. The type of gelling agent did not greatly affect the postautoclave p
H; mean values among gelling agents were within 0.05 pH units. Postaut
oclave pH of MS medium was lower than that of WPM or GB. This study ve
rifies the need to observe uniform sterilization protocols to maintain
consistency in the chemical and physical properties of media.