Michael Knoblauch - New Insights on the Physiology and Cell Biology of Phloem Transport and Unloading

Abstract: Vascular systems allow organisms to distribute resources internally by bulk flow and thus to overcome size limitations set by diffusion. In plants, the evolution of vascular tissues enabled the development of trees and forests and was accompanied by a major increase in the productivity of terrestrial ecosystems. The process of phloem transport and unloading plays a critical role in allocating photoassimilates to sinks which in form of cereals, tubers, roots etc. represent the major food sources for humans. The cellular processes of phloem transport and allocation control at the site of phloem unloading, however, are hardly investigated and poorly understood. Recent data suggest that the current model of phloem unloading - the high pressure manifold model - does not accurately describe the events in the unloading zone. New data on the physiology and cell biology of phloem transport and unloading will be pressented.