title: Modeling uptake kinetics of cadmium by field-grown lettuce.
abstract: Cadmium uptake by field grown Romaine lettuce treated with P-fertilizers of different Cd levels was investigated over an entire growing season. Results indicated that the rate of Cd uptake at a given time of the season can be satisfactorily described by the Michaelis-Menten kinetics, that is, plant uptake increases as the Cd concentration in soil solution increases, and it gradually approaches a saturation level. However, the rate constant of the Michaelis-Menten kinetics changes over the growing season. Under a given soil Cd level, the cadmium content in plant tissue decreases exponentially with time. To account for the dynamic nature of Cd uptake, a kinetic model integrating the time factor was developed to simulate Cd plant uptake over the growing season: C Plant=C Solution.PUF max.exp[-b.t], where C Plant and C Solution refer to the Cd content in plant tissue and soil solution, respectively, PUF max and b are kinetic constants.
authors.affiliation: Department of Environmental Sciences, University of California, 900 University Avenue, Riverside, CA 92521, USA. chenweip@yahoo.com.cn
authors.forename: Weiping
authors.initials: W
authors.lastname: Chen
authors.forename: Lianqing
authors.initials: L
authors.lastname: Li
authors.forename: Andrew C
authors.initials: AC
authors.lastname: Chang
authors.forename: Laosheng
authors.initials: L
authors.lastname: Wu
authors.forename: Soon-Ik
authors.initials: SI
authors.lastname: Kwon
authors.forename: Rick
authors.initials: R
authors.lastname: Bottoms
mesh_terms: D002104:Cadmium / Q000032:analysis / Q000633:toxicity*; D018556:Crops, Agricultural; D005308:Fertilizers / Q000032:analysis / Q000633:toxicity*; D005506:Food Contamination / Q000032:analysis*; D018545:Lactuca / Q000737:chemistry / Q000378:metabolism*; D008954:Models, Biological; D012621:Seasons; D012989:Soil Pollutants / Q000032:analysis / Q000633:toxicity*; D013995:Time
chemical_list: D005308:Fertilizers; D012989:Soil Pollutants; D002104:Cadmium