MONOTERPENE CYCLASES IN GRAND FIR CALLUS-CULTURES - MODULATION BY ELICITORS AND GROWTH-REGULATORS

Grand fir callus tissue, obtained from debarked sapling stems and cult ured on modified solid Murashige and Skoog medium, when transferred to medium lacking growth regulators or glutamine, or containing autoclav ed extracts of Trichosporium symbioticum or Penicillium brevicompactum , or chitosan, yeast extract or pectinase, displayed up to an eight-fo ld increase in the level of monoterpene cyclase activity compared to c ontrols. The activity induced in the calli was principally limonene cy clase, not pinene cyclase which is the major wound-inducible monoterpe ne synthase in grand fir sapling stems. Mechanical damage to callus ti ssue and treatment with filter-sterilized extracts of wounded stem had no marked effect on cyclase activity levels. The regulation of induce d monoterpene biosynthesis in grand fir calli is different than that o bserved in wounded saplings; the complement of cyclases induced in cul tured cells resembles more closely the constitutive pattern of activit ies present in intact stems.