Restoration of protein level in detached leaves by supply of sulphate

Summary Young leaves were removed from plants grown at a range of sulphur levels and incubated in solutions with and without sulphate. In the absence of sulphate alcohol-insoluble N in the leaves declined irrespective of sulphur status. Sulphate arrested or reversed the decline in leaves from sulphur-deficient plants but had no such effect on leaves from plants grown with adequate sulphur. The difference in response patterns between deficient and non-deficient plants, induced by sulphate treatment could form the basis for a plant test for sulphur deficiency.