Plant physiological responses to hydrologically mediated changes in nitrogen supply on a boreal forest floodplain: a mechanism explaining the discrepancy in nitrogen demand and supply

Lina Koyama; Knut Kielland

Treesearch

Plant physiological responses to hydrologically mediated changes in nitrogen supply on a boreal forest floodplain: a mechanism explaining the discrepancy in nitrogen demand and supply

Formally Refereed

Authors:

Lina Koyama, Knut Kielland

Year:

2011

Type:

Scientific Journal

Station:

Pacific Northwest Research Station

Source:

Plant and Soil. 342(1-2): 129-139

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Abstract

A discrepancy between plant demand and soil supply of nitrogen (N) has been observed in early successional stages of riparian vegetation in interior Alaska. We hypothesized that a hydrologically mediated N supply serves as a mechanism to balance this apparent deficiency of plant N supply. To test this hypothesis, we conducted a tracer experiment and measured the activity of nitrate reductase (NRA) over the summer on the early successional floodplain of the Tanana River in interior Alaska. Isotopic data showed that river-/groundwater was an important source of plant water and that hyporheic N could be absorbed by early successional species.

Keywords

floodplain, hyporheic nitrogen (N), N uptake, plant nitrate use, river discharge chemistry, seasonal change

Citation

Koyama, Lina; Kielland, Knut. 2011. Plant physiological responses to hydrologically mediated changes in nitrogen supply on a boreal forest floodplain: a mechanism explaining the discrepancy in nitrogen demand and supply. Plant and Soil. 342(1-2): 129-139.