Prof. Dr. Hans Lambers (University of Western Australia): Extremely high efficiency of phosphorus acquisition and phosphorus use in Australian plants: can this knowledge be applied to cropping systems? |
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| Startdatum/-zeit: | 21.06.2012 17:15 |
| Enddatum/-zeit: | 21.06.2012 |
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| Adresse: | Fachbereich Biologie/Chemie
Prof. Dr. Renate Scheibe apl. Prof. Dr. H. Merzendorfer Barbarastr. 11 49076 Osnabrück |
| Telefon: | 0541/969-3502 |
| Telefax: | |
| E-Mail: | merzendorfer@biologie.uni-osnabrueck.de |
| Homepage: | http://www.biologie.uni-osnabrueck.de/Fachbereich/?x=ac,dt,eb |
Veranstaltungsort: |
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| Adresse: | Hörsaal 35/E01 FB Biologie/Chemie, Barbarastr. 11 49076 Osnabrück |
| Karte: | Bei Google Maps anzeigen |
| Beschreibung: | Western Australia was a part of Gondwanaland, and some of the most ancient parts of the Earth crust can be found here. Other parts of the landscape originated more recently from calcareous marine deposits. Therefore, the soils of Western Australia are amongst the most heavily leached and nutrient-impoverished in the world. Moreover, the soils on lateritic profiles tightly bind phosphate, so that, phosphorus (P) is also poorly available to plants that are not adapted to these conditions. The southwest of Western Australia is also one of the world's hotspots of higher plant species diversity. Therefore, this environment offers a unique opportunity to study plant adaptations to nutrient-poor conditions. A relatively large proportion of species from the P-poor environments in Western Australia cannot produce an association with mycorrhizal fungi, but, instead, produce cluster roots. These are an adaptation both in structure and in functioning; they release large amounts of exudates, in particular carboxylates. Cluster-root-bearing Proteaceae in Western Australia occur on the most P-impoverished soils, whereas mycorrhizal Myrtaceae tend to inhabit the less P-impoverished soils in this region. The functioning of clusters roots in Proteaceae and Fabaceae has received considerable attention. Dauciform roots in Cyperaceae have been explored less, but function in a similar manner as cluster roots. Growth of cluster roots and dauciform roots is systemically suppressed when leaf P concentrations increase. These roots are short-lived structures, and release large amounts of carboxylates during an exudative burst at rates that are considerably faster than reported for non-specialised roots of a wide range of species. These specialised roots play a pivotal role in mobilisation of P from P-sorbing soil, and effectively mine P that is unavailable to plants without such specialisations. Because the world P reserves are being depleted whilst vast amounts of P are stored in fertilised soils, there is a growing need for crops with a high efficiency of P acquisition. Some Australian native species as well as some existing crops have traits that would be highly desirable for future crops. High P-use efficiency in Proteaceae includes a highly efficient and proficient mobilisation of P from senescing leaves and roots. In addition, many species operate at extremely low leaf P concentrations exhibiting rates of photosynthesis similar to crop plant; expressed per unit leaf P, their rates of photosynthesis are extraordinarily high. I will explore which traits are possibly valuable in future crops and cropping systems, and which ones are best avoided. |
| Kategorie: | Biologisches Kolloqium |
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