Growth Promoting Effect of Cyclitols on Spruce Tissue Cultures

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Abstract
Cultures of Norway spruce callus Picea abies can be maintained indefinitely on medium supplemented with an aqueous extract of malt. The cyclitol content of the malt extract was determined, and it was shown that myo-inositol is one of the active constituents of the extract. The effect of myo-inositol and other cyclitols on callus growth was studied. Although some myo-inositol apparently was produced by the tissue, a growth increase of 15 to 30% resulted from adding 100 mg/1 of this compound to the medium. Sequoyitol, a naturally occurring monomethyl ether of myo-inositol, was as active as myo-inositol itself. (+)-Pinitol, D-inositol, and scyllo-inositol also stimulated growth, but less than the myo-isomer. Quebrachitol, L-inositol, and 3 synthetic isomers (epi-, muco-, and neo-inositol) were inactive. Myo-inositol was the only cyclitol detected in malt extract and in spruce tissue cultured on the standard medium. In the callus, 85 to 90% of the inositol was in free form. Analysis of callus grown on media containing other cyclitols gave no evidence that sequoyitol, (+)-pinitol, or quebrachitol was demethylated by the tissue to the corresponding inositol or that any cyclitol was converted to myo-inositol. The various compounds are apparently active per se.