We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
Oxygen concentration affects nodule anatomy and nitrogenase activity ofAlnus maritima.
- Authors
Kratsch, Heidi A.; Graves, William R.
- Abstract
Alnus maritimais a shrub that associates with N2-fixingFrankiain the wetlands in which it is native. Despite low concentrations in waterlogged soils, O2 is critical to the maintenance of this symbiosis, andFrankia-infected nodules exist on roots of plants in native stands. The objective of the present study was to determine how root-zone O2 concentration influences N2 fixation and the anatomy of nodules onA. maritima. Root zones of plants inoculated with soil from native stands were exposed to eight O2 concentrations. Nitrogenase activity increased with increasing O2 concentration. Photosynthetic rate, plant dry mass, leaf N content, and nodule fresh mass were maximal in plants maintained with 15–25% O2 in the root zone. Nodule counts were maximal on roots maintained at 10% and above 25% O2, and nodules that developed at≤ 2% O2 were< 2 mm in diameter and single-lobed. Mean total area of air spaces within nodules decreased, and mean area per space increased, with increasing O2 concentration. Seasonal and O2-dependent nodule pigmentation was observed. Our data illustrate that O2 is critical to the development of functional symbioses, and that nodules of this species, which are submersed in nature, possess mechanisms for responding to their low-O2 environment.
- Subjects
ALDER; MARINE plants; AQUATIC plants; MARINE organisms; FRANKIA; PLANT physiology; ACTINORHIZAL plants; NITROGEN-fixing plants; SYMBIOSIS
- Publication
Plant, Cell & Environment, 2005, Vol 28, Issue 5, p688
- ISSN
0140-7791
- Publication type
Article
- DOI
10.1111/j.1365-3040.2005.01323.x