Reliance on prey-derived nitrogen
by the carnivorous plant Drosera rotundifolia decreases with increasing
nitrogen deposition
J. Millett1,
B. M. Svensson2,
J. Newton3,
H. Rydin2
Article first published online: 16 APR 2012
DOI: 10.1111/j.1469-8137.2012.04139.x
Summary
•
Carnivory in plants is presumed to be an adaptation to a
low-nutrient environment. Nitrogen (N) from carnivory is expected to become a
less important component of the N budget as root N availability increases.
•
Here, we investigated the uptake of N via roots versus prey of
the carnivorous plant Drosera rotundifolia growing in ombrotrophic bogs
along a latitudinal N deposition gradient through Sweden, using a natural
abundance stable isotope mass balance technique.
•
Drosera rotundifolia plants receiving the lowest level
of N deposition obtained a greater proportion of N from prey (57%) than did
plants on bogs with higher N deposition (22% at intermediate and 33% at the
highest deposition). When adjusted for differences in plant mass, this pattern
was also present when considering total prey N uptake (66, 26 and 26 μg prey N
per plant at the low, intermediate and high N deposition sites, respectively).
The pattern of mass-adjusted root N uptake was opposite to this (47, 75 and
86 μg N per plant).
•
Drosera rotundifolia plants in this study switched from
reliance on prey N to reliance on root-derived N as a result of increasing N
availability from atmospheric N deposition.