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| Titel |
Exudation of organic acids by Lupinus albus and Lupinus angustifolius as
affected by phosphorus supply |
| VerfasserIn |
Werner Hentschel, Oliver Wiche |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250136036
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| Publikation (Nr.) |
 EGU/EGU2016-16986.pdf |
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| Zusammenfassung |
| In phytomining and phytoremediation research mixed cultures of bioenergy crops with
legumes hold promise to enhance availability of trace metals and metalloids in the soil plant
system. This is due to the ability of certain legumes to mobilize trace elements during
acquisition of nutrients making these elements available for co-cultured species. The legumes
achieve this element mobilization by exudating carboxylates and enzymes as well as by
lowering the pH value in the rhizosphere.
The aim of our research was to determine characteristics and differences in the exudation
of Lupinus albus and Lupinus angustifolius regarding to quantitative as to qualitative aspects.
Especially the affection by phosphorus (P) supply was a point of interest. Thus we conducted
laboratory batch experiments, wherein the plants were grown over four weeks under
controlled light, moisture and nutritional conditions on sand as substrate. Half of the plants
were supplied with 12 mg P per kg substrate, the other half were cultivated under a total lack
of P.
After cultivation the plants were transferred from the cultivation substrate into a
0,05 mmol⋅L−1 CaCl2 solution. After two hours the plants were removed, moist and dry
mass off shoots and roots were measured together with the root length (Tennants’ method).
Concentrations of exudated carboxylates in the CaCl2 solution were determined via IC
(column: Metrosept OrganicAcids, eluent 0.5 mol⋅L−1 H2SO4 + 15% acetone, pH=3;
0.5 mL⋅min−1).
As a result four different organic acids were identified (citric acid, fumaric acid, tartaric
acid, malic acid) in concentration ranges of 0.15 mg⋅L−1 (fumaric acid) to 9.21 mg⋅L−1
(citric acid).
Lupinus angustifolius showed a higher exudation rate (in nmol per cm root length per
hour) than Lupinus albus in the presence of phosphorus (e.g. regarding citric acid: 1.99 vs
0.64 nmol⋅(g⋅h)−1). However, as the root complexity and length of L. albus were far higher
than of L. angustifolius, the total amount of exudated organic acids per plant of L. albus was
higher than of L.angustifolius. Thus L.albus should be addressed as the more exudation
effective plant in comparison to L.angustifolius (could be addressed as the more efficient
one). Since organic acids in the rhizosphere of intermingling root systems of intercropped
species play a key role during mobilization of trace metals our result clearly show
that L.albus is most suitable for intercropping in a sense of phytoremediation and
phytomining.
These studies have been carried out in the framework of the PhytoGerm project financed
by the Federal Ministry of Education and Research, Germany. |
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