In situ analysis of introduced Frankia populations in root nodules of Alnus glutinosa grown under different water availability

Document Type

Conference Proceeding

Publication Date

1-1-1999

Abstract

The competitive ability for nodulation of Alnus glutinosa (L.) Gaertn. plants by Frankia strains inoculated into soil with indigenous Frankia populations was studied at two matric potentials representing 'dry' (-0.016 MPa) and 'wet' (-0.001 MPa) conditions. In pots kept at a matric potential of-0.001 MPa, nitrate concentrations decreased within 3 weeks more than 10-fold to an average of approx. 200 μmol·(g soil dry wt.)-1. After 4 months, nitrate concentrations in these pots were 16 ± 16 and 277 ± 328 μmol·(g soil dry wt.)-1 (mean ± SD) for non-inoculated and inoculated soils, respectively. At a matric potential of -0.016 MPa, nitrate concentrations for non-inoculated and inoculated soils were 687 ± 491 and 1796 ± 1746 μmol·(g soil dry wt.)-1, respectively. Inoculated plants always grew better than their non-inoculated counterparts. The largest plants were found on inoculated soil at a matric potential of -0.001 MPa, whereas the smallest plants were found on non-inoculated soil at the same matric potential. At a matric potential of-0.016 MPa, plants grown on non-inoculated soil were not as tall as those grown on inoculated soil and were slightly chlorotic, indicating that the high level of nitrate in the soil was not providing optimal plant growth conditions. The number of nodule lobes formed on plants was not significantly different among treatments, though size and weight of lobes differed. Nodules from plants grown on inoculated soils always harbored vesicle-producing Frankia populations, while nodules from plants grown on non-inoculated soils harbored only Frankia with distorted vesicles or no Frankia at all. All strains in nodules from plants grown on non-inoculated soil were of Alnus host infection group IIIa. Nodules from plants grown on soil inoculated with strains ArI3 (group IIIa), Ag45/Mut15 (group IV), and AgB1.9 (group I) were also infected by Frankia strain Ag45/Mut15. These results indicate that by inoculation, Frankia populations could be established under conditions that did not favour vesicle formation in root nodules formed by the indigenous Frankia population. Inoculation even in soils with high nitrogen content might therefore be an appropriate strategy to enhance plant growth.

Identifier

0033501169 (Scopus)

Publication Title

Canadian Journal of Botany

External Full Text Location

https://doi.org/10.1139/cjb-77-9-1231

ISSN

00084026

First Page

1231

Last Page

1238

Issue

9

Volume

77

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