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The influence of the ectomycorrhizal fungus Rhizopogon subareolatus on growth and nutrient element localisation in two varieties of Douglas fir (Pseudotsuga menziesii var. menziesii and var. glauca) in response to manganese stress.

Ducić T, Parladé J, Polle A - Mycorrhiza (2008)

Bottom Line: Colonisation with R. subareolatus slightly suppressed DFM growth but strongly reduced that of DFG (-50%) despite positive effects of mycorrhizas on plant phosphorus nutrition.Accumulation of high Mn was not prevented in inoculated seedlings.The hyphal mantle of mycorrhizal root tips accumulated divalent cations such as Ca, but not Mn, thus not providing a barrier against excessive Mn uptake into the plants associated with R. subareolatus.

View Article: PubMed Central - PubMed

Affiliation: Institut für Forstbotanik, Georg-August Universität Göttingen, Büsgenweg 2, 37077, Göttingen, Germany.

ABSTRACT
Acidification of forest ecosystems leads to increased plant availability of the micronutrient manganese (Mn), which is toxic when taken up in excess. To investigate whether ectomycorrhizas protect against excessive Mn by improving plant growth and nutrition or by retention of excess Mn in the hyphal mantle, seedlings of two populations of Douglas fir (Pseudotsuga menziesii), two varieties, one being menziesii (DFM) and the other being glauca (DFG), were inoculated with the ectomycorrhizal fungus Rhizopogon subareolatus in sand cultures. Five months after inoculation, half of the inoculated and non-inoculated seedlings were exposed to excess Mn in the nutrient solution for further 5 months. At the end of this period, plant productivity, nutrient concentrations, Mn uptake and subcellular compartmentalisation were evaluated. Non-inoculated, non-stressed DFM plants produced about 2.5 times more biomass than similarly treated DFG. Excess Mn in the nutrient solution led to high accumulation of Mn in needles and roots but only to marginal loss in biomass. Colonisation with R. subareolatus slightly suppressed DFM growth but strongly reduced that of DFG (-50%) despite positive effects of mycorrhizas on plant phosphorus nutrition. Growth reductions of inoculated Douglas fir seedlings were unexpected since the degree of mycorrhization was not high, i.e. ca. 30% in DFM and 8% in DFG. Accumulation of high Mn was not prevented in inoculated seedlings. The hyphal mantle of mycorrhizal root tips accumulated divalent cations such as Ca, but not Mn, thus not providing a barrier against excessive Mn uptake into the plants associated with R. subareolatus.

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Relative changes in biomass in response to mycorrhization with R. subareolatus and exposure to Mn stress in Douglas fir seedlings (P. menziesii) of the variety menziesii (black) and glauca (hatched). C Non-inoculated control, R inoculated with R. subareolatus, Mn exposed to 10 mM Mn once a week for 5 months. Bars indicate means (±SD). Different letters indicate significant differences at P ≤ 0.05
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Fig1: Relative changes in biomass in response to mycorrhization with R. subareolatus and exposure to Mn stress in Douglas fir seedlings (P. menziesii) of the variety menziesii (black) and glauca (hatched). C Non-inoculated control, R inoculated with R. subareolatus, Mn exposed to 10 mM Mn once a week for 5 months. Bars indicate means (±SD). Different letters indicate significant differences at P ≤ 0.05

Mentions: Because of the large differences in biomass between DFG and DFM, the relative changes were compared to elucidate treatment effects (Fig. 1). For this comparison, the final biomass of non-inoculated, non-stressed seedlings of each variety was set to 100%. The DFM seedlot showed a reduction in biomass (−25%) only when inoculated with R. subareolatus and treated with Mn (Fig. 1). In the DFG seedlot, inoculation with R. subareolatus decreased growth either in the presence or absence of excess Mn (−50%), but Mn had no effect on biomass (Fig. 1).Fig. 1


The influence of the ectomycorrhizal fungus Rhizopogon subareolatus on growth and nutrient element localisation in two varieties of Douglas fir (Pseudotsuga menziesii var. menziesii and var. glauca) in response to manganese stress.

Ducić T, Parladé J, Polle A - Mycorrhiza (2008)

Relative changes in biomass in response to mycorrhization with R. subareolatus and exposure to Mn stress in Douglas fir seedlings (P. menziesii) of the variety menziesii (black) and glauca (hatched). C Non-inoculated control, R inoculated with R. subareolatus, Mn exposed to 10 mM Mn once a week for 5 months. Bars indicate means (±SD). Different letters indicate significant differences at P ≤ 0.05
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2480516&req=5

Fig1: Relative changes in biomass in response to mycorrhization with R. subareolatus and exposure to Mn stress in Douglas fir seedlings (P. menziesii) of the variety menziesii (black) and glauca (hatched). C Non-inoculated control, R inoculated with R. subareolatus, Mn exposed to 10 mM Mn once a week for 5 months. Bars indicate means (±SD). Different letters indicate significant differences at P ≤ 0.05
Mentions: Because of the large differences in biomass between DFG and DFM, the relative changes were compared to elucidate treatment effects (Fig. 1). For this comparison, the final biomass of non-inoculated, non-stressed seedlings of each variety was set to 100%. The DFM seedlot showed a reduction in biomass (−25%) only when inoculated with R. subareolatus and treated with Mn (Fig. 1). In the DFG seedlot, inoculation with R. subareolatus decreased growth either in the presence or absence of excess Mn (−50%), but Mn had no effect on biomass (Fig. 1).Fig. 1

Bottom Line: Colonisation with R. subareolatus slightly suppressed DFM growth but strongly reduced that of DFG (-50%) despite positive effects of mycorrhizas on plant phosphorus nutrition.Accumulation of high Mn was not prevented in inoculated seedlings.The hyphal mantle of mycorrhizal root tips accumulated divalent cations such as Ca, but not Mn, thus not providing a barrier against excessive Mn uptake into the plants associated with R. subareolatus.

View Article: PubMed Central - PubMed

Affiliation: Institut für Forstbotanik, Georg-August Universität Göttingen, Büsgenweg 2, 37077, Göttingen, Germany.

ABSTRACT
Acidification of forest ecosystems leads to increased plant availability of the micronutrient manganese (Mn), which is toxic when taken up in excess. To investigate whether ectomycorrhizas protect against excessive Mn by improving plant growth and nutrition or by retention of excess Mn in the hyphal mantle, seedlings of two populations of Douglas fir (Pseudotsuga menziesii), two varieties, one being menziesii (DFM) and the other being glauca (DFG), were inoculated with the ectomycorrhizal fungus Rhizopogon subareolatus in sand cultures. Five months after inoculation, half of the inoculated and non-inoculated seedlings were exposed to excess Mn in the nutrient solution for further 5 months. At the end of this period, plant productivity, nutrient concentrations, Mn uptake and subcellular compartmentalisation were evaluated. Non-inoculated, non-stressed DFM plants produced about 2.5 times more biomass than similarly treated DFG. Excess Mn in the nutrient solution led to high accumulation of Mn in needles and roots but only to marginal loss in biomass. Colonisation with R. subareolatus slightly suppressed DFM growth but strongly reduced that of DFG (-50%) despite positive effects of mycorrhizas on plant phosphorus nutrition. Growth reductions of inoculated Douglas fir seedlings were unexpected since the degree of mycorrhization was not high, i.e. ca. 30% in DFM and 8% in DFG. Accumulation of high Mn was not prevented in inoculated seedlings. The hyphal mantle of mycorrhizal root tips accumulated divalent cations such as Ca, but not Mn, thus not providing a barrier against excessive Mn uptake into the plants associated with R. subareolatus.

Show MeSH
Related in: MedlinePlus