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Gewählte Publikation:

Rewald, B; Holzer, L; Goransson, H.
(2015): Arbuscular mycorrhiza inoculum reduces root respiration and improves biomass accumulation of salt-stressed Ulmus glabra seedlings
URBAN FOR URBAN GREE. 2015; 14(2): 432-437. FullText FullText_BOKU

Contamination by de-icing salt can severely damage trees in urban areas. Arbuscular mycorrhizal fungi (AM) have been shown to increase plant resistance to excess salinity-mainly by improving nutrient uptake. However, the availability of AM symbionts is limited in urban soils. Because an increased carbon demand for root system maintenance could underlie restricted tree performance, beside well-known restraints to photosynthetic assimilation, this study focuses at possible ameliorating effects of commercial AM inoculum on the respiration of salt-stressed tree root systems. Ulmus glabra seedlings were grown in a well-fertilized sand peat mixture to minimize confounding effects aside from NaCl ion toxicity. Half of the seedlings were inoculated with commercial AM spores; after an establishment phase, some seedlings were treated with 50 mM NaCI. Plant biomass allocation and fine root respiration were measured; root respiration was correlated to biomass accumulation. The salt treatment significantly reduced the biomass of non-inoculated seedlings; biomass of AM plants was not significantly affected by 50 mM NaCl. Without NaCI stress the mycorrhizal plants tended to grow less than the non-inoculated due to the cost of having mycorrhiza-indicating that seedlings were not water or nutrient limited. Fine root respiration increased significantly only in the non-inoculated plants under salt stress. Total and root biomass both showed strong negative correlation with fine root respiration, indicating that the decrease in growth was caused by the higher root respiration of stressed plants. In summary, our results indicate that commercial AM inoculate can prevent a major increase of root respiration under moderate NaCI stress, enabling trees to deploy more assimilated C for growth and, theoretically, defence mechanisms against other stress factors occurring in urban environments. Thus, a valuable strategy to reduced salt-induced stress of arbuscular mycorrhized urban trees is to make sure sufficient symbionts are available, e.g. by artificially supplying commercial AM inoculum to planting pits. (C) 2015 Elsevier GmbH. All rights reserved.
Autor*innen der BOKU Wien:
Rewald Boris
Sanden Hans

Find related publications in this database (Keywords)
De-icing salt
Root carbon consumption
Urban trees

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