ISSN:
1432-0789
Keywords:
Rhizobium meliloti
;
ELISA
;
Growth temperatures
;
Competition
;
Medicago sativa
;
Enzyme-linked immunosorbent assay
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Geosciences
,
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Summary Axenically grown alfalfa (Medicago sativa L. var. Peace) was simultaneously inoculated with Canadian commercial Rhizobium meliloti strains NRG-185 and BALSAC. The plants were grown for 7 weeks in sealed units at five different root temperatures (8°, 13°, 17°, 21°, and 25°C) and at a relatively constant air temperature (24°–30°C). Nodule occupancy by each strain was determined by enzyme-linked immunosorbent assay (ELISA). Nitrogenase activity, nodule fresh weight, and plant dry weight were also measured. The lowest root-temperature regime (8°C) resulted in substantially lower nodule numbers and weights, and plant dry weights, than the higher temperature regimes. Development of nitrogenase activity was completely inhibited at 8°C. The immunoassay of nodule-strain occupancy showed markedly different strain-nodulation responses to the various root-temperature regimes. At 8°C, 63% of nodules were occupied by both strains. Dual strain occupancy decreased from 63% to 2% with increasing root-growth temperature, while the proportion of nodules containing only strain NRG-185 increased from 9% to 75%. Nodules containing only strain BALSAC remained relatively constant at 25% from 8° to 21°C, decreasing slightly at 25°C. The results suggest that root-environment temperatures during the period of nodule formation may have major differential effects on the success of competing rhizobial strains. If this is so, then selection of Rhizobium strains with enhanced low-temperature nodulation capabilities should be possible.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00257663
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