Indexed on: 01 Jun '59Published on: 01 Jun '59Published in: Planta
Not only growing enucleate fragments ofAcetabularia, but also non growing fragments synthesize proteins to a high degree though less than growing ones. Consequently protein increase is independent of growth. This follows also from the fact, that in growing fragments protein increase can proceed for a longer time than growth. Protein increase is not a sufficient condition for growth. This holds probably also forSpirogyra and other cells in which protein synthesis is normally correlated with the enlarging of the cell body.In growing fragments the extent of protein increase is controlled by the extent of growth, and not vice versa, as could be stated by researches on enucleate differently growing fragments. In agreement with this conclusion is the fact, that, if growth is induced in fragments which normally do not grow protein production is enhanced.The kind of nuclear dependence of cytoplasmic biosynthetic activities is discussed. Growth is on its base directly nucleus dependent e. g. the production of precursors of the “morphogenetic substances”. Protein synthesis, however, is only very indirectly nucleus dependent. Up to 56 μg proteins can be synthesized after enucleation, moreover the extent of protein synthesis is in far limits independent of the original protein contents, whereas growth is limited by the amount of morphogenetic substances present within a fragment at the moment of enucleation.