Harvard Forest Research

Amino Acid Production, Turnover, and Plant Uptake in the Temperate Forest

Principal Investigator: Adrien Finzi
Boston University: May 01 2007 - May 01 2010:

Abstract:
Recent research in arctic, alpine and boreal ecosystems shows that amino acids are a critical component of the soil nitrogen (N) cycle (e.g., Chapin et al. 1993, Lipson and Näsholm 2001, Schimel and Bennett 2004). Amino acids are produced and turnover rapidly in soil (Jones 1999, Jones and Kielland 2002), often serving as substrates for mineralization and nitrification (Barraclough 1997, Jones 1999, Jones and Kielland 2002, Finzi and Berthrong 2005). Similarly, several studies have shown that plants have the physiological capacity to take up amino acids (e.g., Kielland 1997, Schmidt and Stewart 1999, Näsholm et al. 2000, Bennett and Prescott 2004, Finzi and Berthrong 2005), often in direct competition with soil microbes (Näsholm et al. 1998, McFarland et al. 2002, Bardgett et al. 2003). Although amino acids are emerging as a critical component of the terrestrial-N cycle (Chapin et al. 2002, Schimel and Bennett 2004), we have so far failed to rigorously quantify their importance to the cycle of soil-N in temperate forests. Thus, the objective of this proposed research is to examine the role of amino acids in the soil N cycle of temperate forests. This research will determine the effects of both tree species and soil parent material on the production of amino acids from soil organic matter and the turnover of amino acids in soils. These measurements of the production and turnover of amino acids will be coupled with a field experiment to determine the difference in the ability of tree species to take up amino acids, NH4+ and NO3- and the relative importance of these forms for the N nutrition of trees. :