Studies on plant growth‐regulating substances: Water uptake by discs from inulin‐storing roots and tubers in response to growth‐substance treatment

Discs of tissue cut from chicory and dandelion roots are shown to take up large amounts of water when treated with solutions of the auxin 2,4‐dichlorophenoxyacetic acid. The effects of disc size, concentration of auxin and cold‐storage of the roots on the magnitude of the response have been studied. A range of plant growth‐regulating chemicals has been examined for the capacity to promote water uptake in chicory root discs. The results are considered both in relation to chemical structure and to the growth responses induced by these compounds in the wheat cylinder and pea segment tests. The evidence indicates that the water uptake response by chicory root tissues provides a useful method for assessing plant growth‐promoting activity.