It has been suggested that the effect of cytokinins in retarding leaf senescence comes about through their incorporation into tRNA. To test this hypothesis, kinetin-8-14C, 6-benzylaminopurine-benzyl-7-14C and adenine-8-3H were applied to detached tobacco leaves, and the nucleic acids were thereafter extracted and chromatographed on MAK columns. Kinetin-8-14C and adenine-8-3H were readily incorporated into RNA in a similar pattern. 6-Benzylaminopurine-benzyl-7-14C was effective in delaying chlorophyll loss but was not incorporated into any nucleic-acid fraction. It is concluded that the possibility of cytokinins retarding leaf senescence by completion of tRNA is not supported.
ASJC Scopus subject areas
- Plant Science