Root surface acid phosphatases and their role in phosphorus assimilation by Eriophorum vaginatum
Eriophorum vaginatum is a dominant plant in much of the arctic tundra ecosystem where phosphorus is frequently a limiting nutrient. The mineralization of this organic phosphorus was thought to be principally controlled by microbial respiration, however, more recent work shows that extracellular soil phosphatases are the principal regulators. The existence of plant root and mycorrhizal surface phosphatases which are capable of hydrolyzing organic phosphorus compounds, suggests that soil organic phosphorus may be directly utilized by plants. Since E. vaginatum is a tussock forming sedge with a very dense annually produced rooting system which can exploit most of the tussock soil volume, its surface phosphatases may play a dominant role in organic phosphorus hydrolysis into inorganic phosphorus. Of equal significance would be the potential for this activity to contribute to the phosphorus nutrition through the coupling of phosphorus hydrolysis on the root and root uptake of the resultant inorganic phosphorus. Phosphatase activity was investigated and found to be uniformly distributed along the surface of the root. Kinetic analysis of the enzyme gave estimates of 9.23 mM for the apparent Km and 1.61 * 10/sup -3/ ..mu..moles mm-2 hr/sup -1/ for the apparent Vmax. Saturation values for E. vaginatum phosphatases are about 3 times higher than average soil solution organic phosphorus concentrations. 12 refs., 4 figs.
- Research Organization:
- Clarkson Univ., Potsdam, NY (USA). Dept. of Biology
- DOE Contract Number:
- FG02-86ER60492
- OSTI ID:
- 7126283
- Report Number(s):
- DOE/ER/60492-4; ON: DE88014136
- Resource Relation:
- Other Information: Portions of this document are illegible in microfiche products
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
PHOSPHATASES
BIOCHEMICAL REACTION KINETICS
PHOSPHORUS
SOIL CHEMISTRY
PHOSPHORUS 32
PHYTIC ACID
PLANTS
ROOT ABSORPTION
TRACER TECHNIQUES
TRITIUM COMPOUNDS
TUNDRA
ABSORPTION
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CHEMISTRY
DAYS LIVING RADIOISOTOPES
ELEMENTS
ENZYMES
ESTERASES
ESTERS
HYDROLASES
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
LABELLED COMPOUNDS
LIGHT NUCLEI
NONMETALS
NUCLEI
ODD-ODD NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
PHOSPHORIC ACID ESTERS
PHOSPHORUS ISOTOPES
RADIOISOTOPES
REACTION KINETICS
UPTAKE
520101* - Environment
Aquatic- Basic Studies- Radiometric Techniques- (-1989)
550201 - Biochemistry- Tracer Techniques