Changes in activities of some enzymes in water-stressed rosmarinus officinalis callus cultures

ABSTRACT

Callus cultures of rosemary, [Rosmarinus officinalis L.], were initiated from leaf segments cultured on Murashige and Skoog's [MS] medium supplemented with 1.0 mg 1[-1] NAA and 1.0 mg 1[-1] BAP. Cultures were exposed to increasing mannitol concentrations [from 0.0 to 2 percent] to induce osmotic stress in the medium. The results indicated that addition of mannitol to the media reduced growth and slightly increased protein content. The lipid content dropped concomitant with increasing levels of mannitol in the media. The levels of protein and lipids found in leaves of intact plant were, in general, higher than those found in the leaves-derived callus cultures. Maximum values of peroxidase activity were obtained from callus cultures grown on mannitol-free medium. Peroxidase activity was markedly suppressed when the callus cultures were cultured on media containing different levels of mannitol. In contrast, there was an increase in lipase activity in mannitol exposed cultures. Addition of 2 percent mannitol to the medium induced doubling of the level of lipase activity. Callus cultures under control condition were 29 and 8-fold greater in peroxidase and lipase activities than intact plant, respectively