How does water-stressed corn respond to potassium nutrition? A shoot-root scale approach study under controlled conditions
2018
Jordan-Meille, Lionel | Martineau, Elsa | Bornot, Yoran | Lavres, José | Abreu-Junior, Cassio | Domec, Jean-Christophe | Interactions Sol Plante Atmosphère (UMR ISPA) ; Institut National de la Recherche Agronomique (INRA)-Ecole Nationale Supérieure des Sciences Agronomiques de Bordeaux-Aquitaine (Bordeaux Sciences Agro) | SILVA (SILVA) ; Institut National de la Recherche Agronomique (INRA)-AgroParisTech-Université de Lorraine (UL) | Universidade de São Paulo = University of São Paulo (USP)
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Afficher plus [+] Moins [-]anglais. Potassium (K) is generally considered as being closely linked to plant water dynamics. Consequently, reinforcing K nutrition, which theoretically favors root growth and specific surface, extends leaf lifespan, and regulates stomatal functioning, is often used to tackle water stress. We designed a greenhouse pot-scale device to test these interactions on corn (Zea mays L.), and to analyze their links to plant transpiration. Three levels of K nutrition were combined with two water-supply treatments. Shoot and root development and growth were continuously measured during a 60-day-long experiment. Individual plant transpiration was measured by weighing pots and by calculating water mass balances. The results showed that, although K deficiency symptoms resembled those caused by water shortage, there was no advantage to over-fertilizing water-stressed plants. K failed to decrease either the transpiration per unit leaf surface or to improve water use efficiency. The link between K nutrition and plant transpiration appears solely attributable to the effect of K on leaf area. We conclude that K over-fertilization could ultimately jeopardize crops by enhancing early-stage water transpiration to the detriment of later developmental stages.
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