FN Archimer Export Format
PT J
TI Effect of plant photosynthesis, carbon sources and ammonium availability on nitrogen fixation rates in the rhizosphere of Zostera noltii
BT 
AF WELSH, DT
   BOURGUES, S
   DEWIT, R
   AUBY, Isabelle
AS 1:1;2:1;3:1;4:1;
FF 1:;2:;3:;4:;
C1 Univ Bordeaux, France
C2 UNIV BORDEAUX, FRANCE
IF 2.19
TC 46
UR https://archimer.ifremer.fr/doc/00151/26266/24350.pdf
LA English
DT Article
DE ;acetylene reduction;nitrogen fixation;rhizosphere;Zostera noltii;plant photosynthesis;root exudates;carbon sources;ammonium
AB Rates of nitrogen fixation (measured as acetylene reduction) in the rhizosphere of the seagrass Zostera noltii were highly dependent upon plant photosynthetic activity being significantly stimulated at elevated CO2 concentrations and by light, both in the short-term and over diurnal cycles. Stimulation by light became insignificant when 5 mM sucrose was added to the sediment porewater, indicating that in the absence of added carbon sources, light stimulation was due to direct inputs of plant photosynthate to the rhizosphere. Addition of a range of carbon sources to the rhizosphere sediment stimulated rates of acetylene reduction, with this stimulation being significant for sucrose and lactate. Surprisingly, whilst low additions of ammonium to the sediment porewater (10 to 50 mu M) inhibited 50% of acetylene reduction activity, approximately 30% of this activity persisted in the presence of 1 mM ammonium chloride; this indicating that in at least a proportion of the N-fixing community, nitrogenase activity was not regulated in the short term by the availability of alternative nitrogen sources.
PY 1997
PD MAY
SO Aquatic Microbial Ecology
SN 0948-3055
PU Inter-research
VL 12
IS 3
UT A1997XD13100009
BP 285
EP 290
DI 10.3354/ame012285
ID 26266
ER

EF