TY  - JOUR
AU  - Koponen, P.
AU  - Nygren, P.
AU  - Domenach, A.M.
AU  - Le Roux, C.
AU  - Saur, E.
AU  - Roggy, J.C.
PY  - 2003//
TI  - Nodulation and dinitrogen fixation of legume trees in a tropical freshwater swamp forest in French Guiana
T2  - J. Trop. Ecol.
JO  - Journal of Tropical Ecology
SP  - 655
EP  - 666
VL  - 19
PB  - CAMBRIDGE UNIV PRESS
KW  - acetylene reduction assay
KW  - Bradyrhizobium
KW  - flooding
KW  - microtopography
KW  - N-15 natural abundance method
KW  - 16S rDNA sequencing
N2  - Nodulated legume trees comprised 43% of the stand basal area in the low, most frequently flooded microsites, and 23% in higher, drier microsites in a tropical freshwater swamp forest in French Guiana. Dinitrogen fixation in Pterocarpus officinalis, Hydrochorea corymbosa and Inga pilosula was confirmed by acetylene reduction assay (ARA), presence of leghaemoglobin in nodules and the N-15 natural abundance method. The results for Zygia cataractae were inconclusive but suggested N-2 fixation in drier microsites. Nodulated Inga disticha had a N-15-to-N-14 ratio similar to non-N-2-fixing trees, but ARA indicated nitrogenase activity and leghaemoglobin was present in nodules. All bacterial strains were identified as Bradyrhizobium spp. according to the partial 16S rDNA sequences, and they were infective in vitro in the model species Macroptilium atropurpuretan. About 35-50% of N in the leaves of P. officinalis, H. corymbosa and I. pilosula was fixed from the atmosphere. Dinitrogen fixation was estimated to contribute at least 8-13% and 1728% to whole-canopy N in high and low microsites, respectively. Symbiotic N, fixation appears to provide both a competitive advantage to legume trees under N-limited, flooded conditions and an important N input to neotropical freshwater swamp forests.
SN  - 0266-4674
N1  - ISI:000186710800005
ID  - Koponen_etal2003
ER  -