Uptake and translocation of manganese in seedlings of two varieties of Douglas fir (Pseudotsuga menziesii var. viridis and glauca).
Douglas fir (Pseudotsuga menziesii) variety glauca (DFG) but not the variety viridis (DFV) showed symptoms of manganese (Mn) toxicity in some field sites. We hypothesized that these two varieties differed in Mn metabolism. To test this hypothesis, biomass partitioning, Mn concentrations, subcellular localization and 54Mn-transport were investigated. Total Mn uptake was three-times higher in DFG than in DFV. DFV retained > 90% of 54Mn in roots, whereas > 60% was transported to the shoot in DFG. The epidermis was probably the most efficient Mn barrier since DFV contained lower Mn concentrations in cortical cells and vacuoles of roots than DFG. In both varieties, xylem loading was restricted and phloem transport was low. However, sieve cells still contained high Mn concentrations. DFV displayed higher biomass production and higher shoot : root ratios than DFG. Our results clearly show that both varieties of Douglas fir differ significantly in Mn-uptake and allocation patterns rendering DFG more vulnerable to Mn toxicity.
Institut für Forstbotanik, Büsgenweg 2, Georg-August Universität, D-37077 Göttingen, Germany.
Tanja
T
Ducić
Ludger
L
Leinemann
Reiner
R
Finkeldey
Andrea
A
Polle
D001692:Biological Transport; D018533:Biomass; D008345:Manganese / Q000032:analysis / Q000378:metabolism*; D046529:Microscopy, Electron, Transmission; D018517:Plant Roots / Q000033:anatomy & histology / Q000254:growth & development / Q000378:metabolism; D018520:Plant Shoots / Q000033:anatomy & histology / Q000254:growth & development / Q000378:metabolism; D028224:Pseudotsuga / Q000033:anatomy & histology / Q000254:growth & development / Q000378:metabolism*; D036226:Seedlings / Q000033:anatomy & histology / Q000254:growth & development / Q000378:metabolism*; D013045:Species Specificity
D008345:Manganese