ISSN:
1432-0789
Keywords:
Kinetic model
;
Multiphasic uptake
;
Zn uptake isotherms
;
Mycorrhizal corn
;
Zea mays L.
;
Glomus macrocarpum
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Geosciences
,
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Summary The kinetics of Zn absorption were studied in mycorrhizal (Glomus macrocarpum) and non-mycorrhizal roots of corn (Zea mays L.) at pH 6.0 at Zn concentrations of 75 μmol to 1.07 mol m-3. Five concentration-dependent phases of Zn absorption were recognized; phase 0 (1.5–4.0 mmol m-3) was linear but the other four phases (4.0 mmol to 1.07 mol m-3) obeyed Michaelis-Menten kinetics. At low concentrations (less than 4 mmol m-3), sigmoidal kinetics of Zn absorption were observed. The absorption of Zn by mycorrhizal maize was greater at low concentrations but decreased at higher levels. This appeared to be a result of a higher maximal uptake rate in phase 1 and lower K m values in the subsequent phases. Kinetic models yielding continuous isotherms could not account for the observed multiphasic pattern.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00340577
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