Effect of gibberellic acid on K+ (Rb+) uptake and transport in sunflower roots |
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Authors: | Manuel Benlloch José M Fournier Manuel Díaz de la Guardia |
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Institution: | Cátedra de Fisiología Vegetal, Escuela Técnica Superior de Ingenieros Agrónomos, Universidad de Córdoba, Aparado 3048, Córdoba, Spain. |
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Abstract: | Four-week-old sunflower plants ( Helianthus annuus L. cv. Halcón), grown in different nutrient solutions, were used to study the effects of gibberellic acid (GA3) on K+ (Rb+) uptake by roots or transport to the shoot. Gibberellic acid application to the nutrient solution did not affect the exudation process of excised roots. When GA3 was sprayed on leaves 2 to 6 days before excising the roots, the rate of exudation and the K+ flux increased. When the exudation study was done keeping the roots in a nutrient solution in which Rb+ replaced K+, the GA3 effects were evident also on Rb+ uptake and transport. In intact plants, GA3 increased the Rb+ transported to the shoot but did not affect Rb+ accumulation in the root. It is suggested that these GA3 effects can be explained if it is assumed that GA3 acts on the transport of ions to the xylem vessels. |
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Keywords: | Exudation Helianthus annuus ion transport ion uptake intact plant potassium |
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