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Nitrogen cycling dynamics in the carnivorous northern pitcher plant, Sarracenia purpurea
Author(s) -
BUTLER J. L.,
ELLISON A. M.
Publication year - 2007
Publication title -
functional ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.272
H-Index - 154
eISSN - 1365-2435
pISSN - 0269-8463
DOI - 10.1111/j.1365-2435.2007.01307.x
Subject(s) - biology , nutrient , growing season , botany , carnivorous plant , cycling , nitrogen cycle , photosynthesis , nutrient cycle , inflorescence , sink (geography) , agronomy , nitrogen , ecology , predation , history , physics , archaeology , quantum mechanics , cartography , geography
Summary1 In nutrient‐poor environments, plants employ many strategies to acquire and recycle scarce nutrients. Predictable relationships among a variety of leaf traits, including leaf nitrogen (N) suggest that how plants obtain, use, store and re‐use N is a major component of plant fitness. The northern pitcher plant, Sarracenia purpurea , receives nitrogen from multiple sources: NH 4 and NO 3 dissolved in precipitation; N mineralized from captured prey; the scant N in saturated peat; and N remobilized from storage. In two greenhouse experiments, we examined N cycling in S. purpurea and consider how these dynamics relate to prior observations that this carnivorous plant has an unusually low photosynthetic rate for its tissue N content. 2 In the first experiment we assessed assimilation, translocation, storage and remobilization of 15 N supplied to pitchers and roots. In the second experiment, we examined how 15 N assimilated by the first pitcher produced at the start of the growing season contributed to the production and maintenance of subsequent pitchers, roots and rhizomes. 3 Patterns of N cycling were similar at the individual‐leaf and whole‐plant level. Pitchers assimilated 55%–69% of available 15 N and served as both the largest sink for newly assimilated N (> 90% of the 15 N assimilated during 2004) and the largest source of N remobilization the following spring. In contrast, N assimilated by roots was low and accounted for < 2·5% of the overall S. purpurea N budget. Sarracenia purpurea used both stored N and newly‐acquired N throughout the growing season. The importance of stored N decreased throughout the growing season as newly assimilated N contributed more to later pitcher production. 4 Our detailed mechanistic analysis of nitrogen cycling dynamics of S. purpurea suggests why this plant has a low photosynthetic rate for its tissue N content. Excess nitrogen is stored for future use, and production of new pitchers is primarily aimed at enhancing prey capture rather than increasing photosynthetic tissue.