Effect of Kinetin on Ribosomes of Excised Barley Leaves

The changes in the amount and the composition of ribosomes in excised barley leaves floated on water or on 10 mg/l kinetin solution in the dark were examined. The rapid loss of polyribosomes and ribosomes in leaves floated on water was greatly retarded by kinetin. The ribosomes‐polyribosomes which originally contained 49 per cent protein showed substantial decline in protein content in leaves floated on water but only slight decline in leaves floated on kinetin solution. It is suggested that kinetin by stimulating RNA synthesis and by suppressing the activities of rihonuclease and peplidase may preserve the ribosomes in excised leaves.