Endogenous Levels Of Cytokinins In Ageing Cucumber Cotyledons

ABSTRACT

ENDOGENOUS LEVELS OF CYTOKININS IN AGEING

CUCUMBER COTYLEDONS

John A.G. Poku, M.Sc.

University of Guelph, 1974

Supervisor:

Professor R.A. Fletcher

There are several procedures for isolating cytokinins which

involve a number of steps including extraction, solvent fractionation

and column or paper chromatography. Various combinations of these

procedures were tried in an attempt to isolate cytokinins from cucumber

cotyledons. It was found that with this tissue it was preferable to

omit a few steps to minimize the loss, of cytokinins activity.

The endogenous cytokinin levels in etiolated cucumber cotyledons

of different ages were estimated and compared with the capacity of

the cotyledons to produce chlorophyll after exposure to light. There

was a parallel relationship between cytokinin levels and chlorophyll

production. The cytokinin levels were highest in 8 day old cotyledons,

at which time the production of chlorophyll was also maximal. It is

proposed that cytokinins have an important role in chlorophyll production.