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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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Box-and-whisker diagrams depicting the range of Mn concentrations in cell walls and vacuoles of different cell types in roots and fungal tissues of mycorrhizal and non-mycorrhizal Douglas fir plants (P. menziesii) of the varieties menziesii (DFM) and glauca (DFG). Mn stress: hatched boxes. DFM: Mycorrhizal (A) and non-mycorrhizal root tips (C). DFG: Mycorrhizal (B) and non-mycorrhizal root tips (D). HM Hyphal mantle, HN Hartig net, EW epidermal cell wall, EV epidermal cell vacuole, CW cortical cell wall, CV cortical cell vacuole, CC central cylinder, whole cells. (n = 15)
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Fig3: Box-and-whisker diagrams depicting the range of Mn concentrations in cell walls and vacuoles of different cell types in roots and fungal tissues of mycorrhizal and non-mycorrhizal Douglas fir plants (P. menziesii) of the varieties menziesii (DFM) and glauca (DFG). Mn stress: hatched boxes. DFM: Mycorrhizal (A) and non-mycorrhizal root tips (C). DFG: Mycorrhizal (B) and non-mycorrhizal root tips (D). HM Hyphal mantle, HN Hartig net, EW epidermal cell wall, EV epidermal cell vacuole, CW cortical cell wall, CV cortical cell vacuole, CC central cylinder, whole cells. (n = 15)

Mentions: To find out whether seedlings from different seedlots differed in the subcellular localisation of Mn and other nutrients, we investigated cross sections of root tips employing energy-dispersive X-ray microanalyses (Fig. 3). Mycorrhizal non-stressed plants of DFM (Fig. 3a) and DFG (Fig. 3b) showed a relatively homogenous distribution of Mn across all tissues. There were neither pronounced differences between Mn concentrations in root cell walls or in vacuoles nor between these plant tissues and fungal tissues such as hyphal mantle or Hartig net. Non-mycorrhizal non-stressed plants of the seedlot DFG displayed higher Mn concentrations in the cortical vacuole than those of mycorrhizal seedlings (P = 0.016, Fig. 3b,d). Overall, there were no important differences between mycorrhizal and non-mycorrhizal tissues.Fig. 3


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)

Box-and-whisker diagrams depicting the range of Mn concentrations in cell walls and vacuoles of different cell types in roots and fungal tissues of mycorrhizal and non-mycorrhizal Douglas fir plants (P. menziesii) of the varieties menziesii (DFM) and glauca (DFG). Mn stress: hatched boxes. DFM: Mycorrhizal (A) and non-mycorrhizal root tips (C). DFG: Mycorrhizal (B) and non-mycorrhizal root tips (D). HM Hyphal mantle, HN Hartig net, EW epidermal cell wall, EV epidermal cell vacuole, CW cortical cell wall, CV cortical cell vacuole, CC central cylinder, whole cells. (n = 15)
© Copyright Policy
Related In: Results  -  Collection

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

Fig3: Box-and-whisker diagrams depicting the range of Mn concentrations in cell walls and vacuoles of different cell types in roots and fungal tissues of mycorrhizal and non-mycorrhizal Douglas fir plants (P. menziesii) of the varieties menziesii (DFM) and glauca (DFG). Mn stress: hatched boxes. DFM: Mycorrhizal (A) and non-mycorrhizal root tips (C). DFG: Mycorrhizal (B) and non-mycorrhizal root tips (D). HM Hyphal mantle, HN Hartig net, EW epidermal cell wall, EV epidermal cell vacuole, CW cortical cell wall, CV cortical cell vacuole, CC central cylinder, whole cells. (n = 15)
Mentions: To find out whether seedlings from different seedlots differed in the subcellular localisation of Mn and other nutrients, we investigated cross sections of root tips employing energy-dispersive X-ray microanalyses (Fig. 3). Mycorrhizal non-stressed plants of DFM (Fig. 3a) and DFG (Fig. 3b) showed a relatively homogenous distribution of Mn across all tissues. There were neither pronounced differences between Mn concentrations in root cell walls or in vacuoles nor between these plant tissues and fungal tissues such as hyphal mantle or Hartig net. Non-mycorrhizal non-stressed plants of the seedlot DFG displayed higher Mn concentrations in the cortical vacuole than those of mycorrhizal seedlings (P = 0.016, Fig. 3b,d). Overall, there were no important differences between mycorrhizal and non-mycorrhizal tissues.Fig. 3

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