Water Status and Growth of Callus In Sturt's Desert Pea (Swainsona formosa) as Affected by Media Condition

This work was undertaken to investigate response of callus and the water status of Sturt's desert pea (Swainsona formosa) in vitro under various environmental stress conditions. Water potential of culture media ranged from -0.27MPa to -1.05MPa so that salt and osmotic stress and different concentration of sucrose could be applied to Sturt's desert pea calli grown in the tissue culture media. The percent increase in calli was highest in standard MS medium with 30g L-1 sucrose but was not so when the water potential of medium was adjusted to the same water potential using standard MS plus mannitol. The water potential of callus tissue was almost the same as that of culture media at any range of MS and sucrose concentrations. Turgor of callus tissue did not alter significantly under any stress conditions. It is concluded that the optimum concentration of salt, sucrose and water status of medium could be estimated by this method and that standard MS concentration and its water status are suitable for the formation of Sturt's desert pea calli.