Response of Tree Root function to Chronic Nitrogen Deposition

Quanying Du, Penn State

March 4, 2010 @ 12:20 pm to 01:10 pm

10 Tyson

Atmospheric nitrogen (N) deposition is increasing as a result of N fertilization and fossil fuel use, and will have a large impact on forest ecosystem net primary productivity. The change of fine root standing crop under elevated N supply is crucial to understanding ecosystem-level C sequestration and nutrient cycling, and is_the net result of_changes in root production and mortality.Several factors exhibit stress on plant roots under chronic levels of high N that could affect mortality. These include N-induced enhancement in_reactive oxygen and nitrogen species, as well as decreased_soil solution base cation to aluminum ratio._These controls over root mortality, as well as aboveground primary productivity under elevated N are being assessed aross_6 long-term N addition sites. Preliminary data indicates_the response of root lifespan to elevated N were inconsistent,_but could be expressed by differences in root stress levels. I will be integrating field research with controlled experiments in the greenhouse, to_detect stress thresholds for dominant species of NE forests and provide baseline data for modelling purposes.

Contact

Kristen Granger
klg297@psu.edu