Manganese toxicity in two varieties of Douglas fir (Pseudotsuga menziesii var. viridis and glauca) seedlings as affected by phosphorus supply
- 1 January 2007
- journal article
- research article
- Published by CSIRO Publishing in Functional Plant Biology
- Vol. 34 (1), 31-40
- https://doi.org/10.1071/fp06157
Abstract
Manganese (Mn) is an essential micronutrient in all organisms but may become toxic when present in excess. To investigate whether interior and coastal varieties of Douglas fir [Pseudotsuga menziesii (Mirbel) Franco, var. glauca (DFG) and var. viridis (DFV)] differed in Mn tolerance, seedlings were exposed to excess Mn in hydroponic solutions. Root growth, biomass production, Mn concentrations in different tissues and Mn subcellular localisation were determined. Both varieties showed similar whole-plant Mn accumulation and biomass reduction in response to increases in Mn in the nutrient solution. Since excess Mn inhibited root elongation growth more strongly in DFG than in DFV, biomass allocation in DFV was shifted towards a relative increase in root biomass and a relative decrease in DFG. X-ray microanalysis showed that Mn enrichment in cell walls and vacuoles of DFV root cortex and epidermis cells was higher than in DFG. In roots, precipitates were observed in which Mn concentrations correlated with phosphorus (P) and to a minor extent with calcium. We suggest that the higher persistence of root growth under Mn stress in DFV was caused by greater entrapment in the vacuole and in the apoplast and by more efficient Mn detoxification in insoluble complexes with P than in DFG. To investigate whether P supply affected Mn uptake and toxicity, Douglas fir seedlings were exposed to excess Mn under P deficiency. In P-limited seedlings of both varieties, roots growth was less sensitive to excess Mn than under sufficient P-supply, although in planta Mn concentrations were not diminished. In DFG, which maintained P homeostasis under limited P supply, the negative effect of Mn stress was partially reversed, showing that Mn susceptibility is affected by P metabolism.Keywords
This publication has 35 references indexed in Scilit:
- Uptake and translocation of manganese in seedlings of two varieties of Douglas fir (Pseudotsuga menziesii var. viridis and glauca)New Phytologist, 2006
- Effect of Manganese Toxicity on the Proteome of the Leaf Apoplast in CowpeaPlant Physiology, 2003
- Tolerance of tropical common bean genotypes to manganese toxicity: Performance under different growing conditionsJournal of Plant Nutrition, 1999
- Light and Excess ManganesePlant Physiology, 1998
- Ernährungszustand der Douglasie (Pseudotsuga menziesii [Mirb.] Franco) auf dänischen und deutschen Standorten im Vergleich zu ihrem natürlichen VerbreitungsgebietEuropean Journal of Forest Research, 1996
- Protein Phosphatase 2B of Saccharomyces Cerevisiae is Required for Tolerance to Manganese, in Blocking the Entry of ions into the CellsJBIC Journal of Biological Inorganic Chemistry, 1995
- Agar standards for quantitative X-ray microanalysis of resin-embedded plant tissuesJournal of Microscopy, 1994
- Uptake and long-distance transport of phosphate, potassium and chloride in relation to internal ion concentrations in barley: evidence of non-allosteric regulationPlanta, 1984
- Nutrient solution growth of sorghum and corn in mineral nutrition studiesJournal of Plant Nutrition, 1982
- Perchloric acid procedure for wet-ashing organics for the determination of mercury (and other metals)Analytical Chemistry, 1974