Subcellular compartmentation of elements in non-mycorrhizal and mycorrhizal roots of Pinus sylvestris: an X-ray microanalytical study. II. The distribution of calcium, potassium and sodium

• Published in: The New phytologist Vol. 145; no. 2; pp. 321 - 331
• Main Authors: BÜCKING, HEIKE, HEYSER, WOLFGANG
• Format: Journal Article
• Language: English
• Published: Cambridge, UK Cambridge University Press 01.02.2000; Blackwell
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; Calcium; cell wall components; Cell walls; cytochemistry; Cytoplasm; diammonium phosphate; Economic plant physiology; ectomycorrhizae; Endodermis; Fundamental and applied biological sciences. Psychology; histochemistry; Infections; mineral content; nutrient availability; nutrient content; nutrient uptake; Parasitism and symbiosis; Paxillus involutus; Phosphates; Pinus sylvestris; Pisolithus tinctorius; Plant physiology and development; Plant roots; Plants; Potassium; potassium phosphates; roots; Seedlings; sodium; sodium phosphate; Suillus bovinus; Symbiosis; Symbiosis (nodules, symbiotic nitrogen fixation, mycorrhiza...); vacuoles; X‐ray microanalysis; Paxillus involutus; sodium; X-ray microanalysis; calcium; potassium; Pinus sylvestris; Suillus bovinus; Pisolithus tinctorius; Symbiosis; Compartmentalization; Cell compartment; Symbionte; Calcium; Root; Ion transfer; Basidiomycetes; Fungi; Sodium; Softwood forest tree; Gymnospermae; Mycorrhiza; Nutrient; Ectomycorrhiza; Coniferales; Spermatophyta; Intraspecific comparison; Localization; Potassium; Thallophyta
• ISSN: 0028-646X; 1469-8137
• DOI: 10.1046/j.1469-8137.2000.00574.x

The inter- and intracellular distribution of the elements calcium, potassium and sodium in non-mycorrhizal and mycorrhizal roots of Pinus sylvestris dependent on different external nutrient supply conditions was detected by energy-dispersive X-ray microanalysis after cryofixation, freeze-drying and pressure infiltration of the material. In non-mycorrhizal and mycorrhizal roots, calcium was mainly detectable in the apoplastic regions. The levels in vacuoles and cytoplasm were near the limits of detection by X-ray microanalysis. Incubation with high concentrations of potassium and sodium, or mycorrhizal infection with Suillus bovinus and Pisolithus tinctorius reduced the amounts of calcium detectable in the roots, especially in the apoplast of cortical cells. The studies revealed that: potassium is mainly localized in cytoplasm and cell walls; the cytoplasmic content is regulated over a wide range of external potassium concentrations; potassium levels in the inner parts of roots are higher than in the outer parts. Mycorrhizal infection with Suillus bovinus had no effect on the inter- and intracellular distribution of potassium in roots but, if the external supply was low, the potassium content in shoots was reduced. In non-mycorrhizal pine roots and those infected with Paxillus involutus an increase in the sodium content of all cell compartments was observed after treatment with high external concentrations of NaH2PO4. However, an increase in sodium content in mycorrhizas of S. bovinus was not detected. The X-ray microanalytical results are discussed in relation to the apoplastic movement of nutrients in non-mycorrhizal and mycorrhizal fine roots of pine and to the demand for these nutrients in different intracellular compartments.