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Hormonal responses of plants to drought

Neales, T.F. Dr; 45 White Avenue, Kew East, Vic. 3102; ph: (03) 9859 2460; now retired.

Research organisation: University of Melbourne, Department of Botany, Parkville Vic 3052

Sponsor: ARC: Australian Research Council


To test the hypothesis that one of the initial responses of plants to drying soils (drought) is the generation of a hormonal stimulus in the roots, which travels to the leaves, where stomatal closure results.


Growing plants (Helianthus annuus) under controlled conditions. Measuring ABA in plant tissues, using ELISA methods. Measuring plant responses to drought in terms of: plant water potential, osmotic adjustment, leaf conductance, and leaf gas exchange characteristics.


It was concluded that the stimulus of drought to the roots of plants induces an increase in the hormone, abscisic acid (ABA) in the roots, xylem sap and leaves. Also that a 'drought' (PEG) treatment to the roots results initially in a synthesis of ABA in the roots, following which ABA synthesis in the leaves contributes to the ABA in the xylem sap.

Period: starting date 1989-01; completion date 1991-06

Status: completed

Keywords: Drought, abscisic acid, ABA, root stimulus, Helianthus tuberosus


Neales, T.F. and McLeod, A.L. (1991). Do leaves contribute to the Abscisic Acid present in the xylem sap of 'droughted' sunflower plants? Plant, Cell and Environment 14, 979-986.

Neales, T.F., Masia, A., Zhang, J. and Davies, W.J. (1989). The effects of partially drying part of the root system of Helianthus tuberosus on the Abscisic Acid content of the roots, xylem sap and leaves. Journal of Experimental Botany 40, 1113-1120.


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