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'And then there were three': highly efficient uptake of potassium by foliar trichomes of epiphytic bromeliads

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dc.contributor.author Winkler, Uwe en
dc.contributor.author Zotz, Gerhard en
dc.date.accessioned 2011-02-16T18:28:21Z
dc.date.available 2011-02-16T18:28:21Z
dc.date.issued 2010
dc.identifier.citation Winkler, Uwe and Zotz, Gerhard. 2010. "<a href="https%3A%2F%2Frepository.si.edu%2Fhandle%2F10088%2F12238">&#39;And then there were three&#39;: highly efficient uptake of potassium by foliar trichomes of epiphytic bromeliads</a>." <em>Annals of Botany</em>. 106 (3):421&ndash;427. <a href="https://doi.org/10.1093/aob/mcq120">https://doi.org/10.1093/aob/mcq120</a> en
dc.identifier.issn 0305-7364
dc.identifier.uri http://hdl.handle.net/10088/12238
dc.description.abstract Background and AimsVascular epiphytes have to acquire nutrients from atmospheric wash out, stem-flow, canopy soils and trapped litter. Physiological studies on the adaptations to nutrient acquisition and plant utilization of nutrients have focused on phosphorus and nitrogen; potassium, as a third highly abundant nutrient element, has received minor attention. In the present study, potassium uptake kinetics by leaves, within-plant distribution and nutrient accumulation were analysed to gain an improved understanding of physiological adaptations to non-terrestrial nutrient supply of plants. MethodsRadioactively labelled 86RbCl was used as an analogue to study uptake kinetics of potassium absorbed from tanks of epiphytes, its plant distribution and the correlation between uptake efficiency and abundance of trichomes, functioning as uptake organs of leaves. Potassium in leaves was additionally analysed by atomic absorption spectroscopy to assess plant responses to potassium deficiency. Key ResultsLabelled rubidium was taken up from tanks over a wide range of concentrations, 0{middle dot}01-90 mM, which was achieved by two uptake systems. In four tank epiphytes, the high-affinity transporters had average Km values of 41{middle dot}2 {micro}M, and the low-affinity transporters average Km values of 44{middle dot}8 mM. Further analysis in Vriesea splenriet showed that high-affinity uptake of rubidium was an ATP-dependent process, while low-affinity uptake was mediated by a K+-channel. The kinetic properties of both types of transporters are comparable with those of potassium transporters in roots of terrestrial plants. Specific differences in uptake velocities of epiphytes are correlated with the abundance of trichomes on their leaf surfaces. The main sinks for potassium were fully grown leaves. These leaves thus function as internal potassium sources, which allow growth to be maintained during periods of low external potassium availability. ConclusionsVascular epiphytes possess effective mechanisms to take up potassium from both highly diluted and highly concentrated solutions, enabling the plant to incorporate this nutrient element quickly and almost quantitatively from tank solutions. A surplus not needed for current metabolism is stored, i.e. plants show luxury consumption. en
dc.relation.ispartof Annals of Botany en
dc.title &#39;And then there were three&#39;: highly efficient uptake of potassium by foliar trichomes of epiphytic bromeliads en
dc.type Journal Article en
dc.identifier.srbnumber 92292
dc.identifier.doi 10.1093/aob/mcq120
rft.jtitle Annals of Botany
rft.volume 106
rft.issue 3
rft.spage 421
rft.epage 427
dc.description.SIUnit STRI en
dc.citation.spage 421
dc.citation.epage 427

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