Title: Mathematical modeling of positron emission tomography (PET) data to assess radiofluoride transport in living plants following petiolar administration

Abstract

Background: Ion transport is a fundamental physiological process that can be studied non-invasively in living plants with radiotracer imaging methods. Fluoride is a known phytotoxic pollutant and understanding its transport in plants after leaf absorption is of interest to those in agricultural areas near industrial sources of airborne fluoride. Here we report the novel use of a commercial, high-resolution, animal positron emission tomography (PET) scanner to trace a bolus of [¹⁸F]fluoride administered via bisected petioles of Brassica oleracea, an established model species, to simulate whole plant uptake of atmospheric fluoride. This methodology allows for the first time mathematical compartmental modeling of fluoride transport in the living plant. Radiotracer kinetics in the stem were described with a single-parameter free- and trapped-compartment model and mean arrival times at different stem positions were calculated from the free-compartment time-activity curves. Results: After initiation of administration at the bisected leaf stalk, [¹⁸F] radioactivity climbed for approximately 10 minutes followed by rapid washout from the stem and equilibration within leaves. Kinetic modeling of transport in the stem yielded a trapping rate of 1.5 +/- 0.3%/min (mean +/- s.d., n = 3), velocity of 2.2 +/- 1.1 cm/min, and trapping fraction of 0.8 +/- 0.5%/cm. Conclusion: Quantitativemore » assessment of physiologically meaningful transport parameters of fluoride in living plants is possible using standard positron emission tomography in combination with petiolar radiotracer administration. Movement of free fluoride was observed to be consistent with bulk flow in xylem, namely a rapid and linear change in position with respect to time. Trapping, likely in the apoplast, was observed. Future applications of the methods described here include studies of transport of other ions and molecules of interest in plant physiology.« less

Authors:

Converse, Alexander K. ^[1]; Ahlers, Elizabeth O. ^[1]; Bryan, Tom W. ^[1]; Hetue, Jackson D. ^[1]; Lake, Katherine A. ^[1]; Ellison, Paul A. ^[1]; Engle, Jonathan W. ^[1]; Barnhart, Todd E. ^[1]; Nickles, Robert J. ^[1]; Williams, Paul H. ^[1]; DeJesus, Onofre T. ^[1]

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+ Show Author Affiliations

1. Univ. of Wisconsin, Madison, WI (United States)

Publication Date:

Sun Mar 15 00:00:00 EDT 2015

Research Org.:

Univ. of Wisconsin, Madison, WI (United States)

Sponsoring Org.:

USDOE Office of Science (SC)

OSTI Identifier:

1192058

Grant/Contract Number:  

SC0005281

Resource Type:

Accepted Manuscript

Journal Name:

Plant Methods

Additional Journal Information:

Journal Volume: 11; Journal Issue: 1; Journal ID: ISSN 1746-4811

Publisher:

BioMed Central

Country of Publication:

United States

Language:

English

Subject:

54 ENVIRONMENTAL SCIENCES; ion transport; positron emission tomography; radiotracer; kinetic modeling; brassica oleracea