Browsing by Subject "Blaue Lupine"

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Einfluss von Phosphatmangel und erhöhter atmosphärischer CO2-Konzentration auf die Wurzelexsudation und ihre Auswirkungen auf Mobilisierung und Aufnahme von Schwermetallen durch verschiedene Lupinenarten und Tomate
(2011) Kawanishi, Ayumi; Römheld, Volker
There is an increasing awareness of a contamination of the food chain by toxic heavy metals as consequence of anthropogenic induced pollution of the environment since the industrialization in the 18. century. In addition the CO2 concentration might promote the biomass formation of plants and thus, via an increased allocation of photo-assimilates into the roots, chemical changes in the rhizosphere. These changes can promote mobility and uptake of various heavy metals by crop plants, too. Therefore it was the main objective of this Ph.D. research, to study the possible consequences of such observed increase in the atmospheric CO2 concentration on the intensification of the rhizosphere chemistry on the uptake of heavy metals by selected plant species in continuation of the research work by Egle (2003) at the University Göttingen. As plant species various lupinus species and tomato were chosen, which differ in principle in their reaction to a low phosphate nutritional status such as root growth characteristics and secretion of protons and carboxylates. As approach two nutrient solution experiments (Chapter 4 and 5) and a soil experiment with heavy metal polluted soils (Chapter 6) were conducted. In both nutrient solution experiments the well-described root-induced changes such as proton and carboxylate release could be confirmed, which were intensified at higher atmospheric CO2 concentrations (Chapter 4 and 5). Surprisingly the detected increase in proton (tomato) and caboxylate release (particularly by white lupin) with a simultaneously increased mobility of Cu and Cd in the soil did not result in an increased concentration of heavy metals in roots and shoots of the growth experimental plants. The unexpected finding in chapter 6 were discussed in the outlook of chapter 6 (6.7) and a repetition of this experiment with consideration of the discussed aspects is urgently recommended.