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Selenium hyperaccumulation by Astragalus (Fabaceae) does not inhibit root nodule symbiosis.
- Source :
-
American journal of botany [Am J Bot] 2012 Dec; Vol. 99 (12), pp. 1930-41. Date of Electronic Publication: 2012 Nov 30. - Publication Year :
- 2012
-
Abstract
- Premise of Study: A survey of the root-nodule symbiosis in Astragalus and its interaction with selenium (Se) has not been conducted before. Such studies can provide insight into how edaphic conditions modify symbiotic interactions and influence partner coevolution. In this paper plant-organ Se concentration ([Se]) was investigated to assess potential Se exposure to endophytes. •<br />Methods: Selenium distribution and molecular speciation of root nodules from Se-hyperaccumulators Astragalus bisulcatus, A. praelongus, and A. racemosus was determined by Se K-edge x-ray absorption spectroscopy. A series of greenhouse experiments were conducted to characterize the response of root-nodule symbiosis in Se-hyperaccumulators and nonhyperaccumulators. •<br />Key Results: Nodules in three Se-hyperaccumulators (Astragalus crotalariae, A. praelongus, and A. preussii) are reported for the first time. Leaves, flowers, and fruits from Se-hyperaccumulators were routinely above the hyperaccumulator threshold (1,000 µg Se g(-1) DW), but root samples rarely contained that amount, and nodules never exceeded 110 µg Se g(-1) DW. Nodules from A. bisulcatus, A. praelongus, and A. racemosus had Se throughout, with a majority stored in C-Se-C form. Finally, an evaluation of nodulation in Se-hyperaccumulators and nonhyperaccumulators indicated that there was no nodulation inhibition because of plant Se tolerance. Rather, we found that in Se-hyperaccumulators higher levels of Se treatment (up to 100 µM Se) corresponded with higher nodule counts, indicating a potential role for dinitrogen fixation in Se-hyperaccumulation. The effect was not found in nonhyperaccumulators. •<br />Conclusions: As the evolution of Se hyperaccumulation in Astragalus developed, root-nodule symbiosis may have played an integral role.
- Subjects :
- Arizona
Astragalus Plant drug effects
Astragalus Plant growth & development
Astragalus Plant microbiology
Bacteria drug effects
Bacteria metabolism
Colorado
Endophytes drug effects
Endophytes metabolism
Fabaceae drug effects
Fabaceae growth & development
Fabaceae microbiology
Fabaceae physiology
Nitrogen Fixation drug effects
Plant Roots drug effects
Plant Roots metabolism
Plant Roots microbiology
Species Specificity
Washington
X-Ray Absorption Spectroscopy
Astragalus Plant physiology
Selenium pharmacology
Soil chemistry
Symbiosis drug effects
Subjects
Details
- Language :
- English
- ISSN :
- 1537-2197
- Volume :
- 99
- Issue :
- 12
- Database :
- MEDLINE
- Journal :
- American journal of botany
- Publication Type :
- Academic Journal
- Accession number :
- 23204487
- Full Text :
- https://doi.org/10.3732/ajb.1200124