Visualization of recently assimilated C along individual maize roots by means of 14C pulse labeling coupled with Phosphor Imaging: Life time of hotspots in the rhizosphere
P 1.13 in Ecosystem Function
Rhizodeposition is of particular interest because it is a primary source of carbon (C) and energy for soil organisms. The C translocated below-ground is not evenly released by the roots, but in distinct areas thus, creating a gradient of rhizodeposits along the root axis. Such locations become hotspots for microorganisms because of high availability of rhizo-C. Despite the general progress made in the field of rhizosphere processes, the appearance of hotspots along individual roots could not be investigated until now, due to the lack of suitable methods. The present experiment was designed to visualize the spatial and temporal distribution of hotspots of recently assimilated C along individual roots by 14CO2 pulse labeling coupled with Phosphor Imaging. Maize plants will be grown in specially constructed thin rhizoboxes with removable front walls. Tilted placing the boxes cause the roots to grow on the removable wall. The shoots will be labeled in a 14CO2 atmosphere, and subsequently the allocation of assimilated 14C in the roots and associated rhizosphere will be traced. This will be done by exchanging the front wall for a phosphor imaging plate. By repeating this step at increasing intervals after the labeling we will gain insight into the dynamics and the life time of 14C hotspots. In order to obtain a precise image of rhizodeposition without interference with the root biomass, the roots will carefully be removed and the imaging plate will be placed back to the blank soil surface. This method will enable to identify and to visualize 14C hotspots in the rhizosphere of living roots and elucidate their dynamics.