Measurement of diffusion within the cell wall in living roots of Arabidopsis thaliana Export

@article{citeulike:2584028, abstract = {To quantify the diffusion constant of small molecules in the plant cell wall, fluorescence from carboxyfluorescein (CF) in the intact roots of Arabidopsis thaliana was recorded. Roots were immersed in a solution of the fluorescent dye and viewed through a confocal fluorescence microscope. These roots are sufficiently transparent that much of the apoplast can be imaged. The diffusion coefficient, Dcw, of CF in the cell wall was probed using two protocols: fluorescence recovery after photobleaching and fluorescence loss following perfusion with dye-free solution. Diffusion coefficients were obtained from the kinetics of the fluorescent transients and modelling apoplast geometry. Apoplastic diffusion constants varied spatially in the root. In the elongation zone and mature cortex, Dcw=(3.2{+/-}1.4)x1011 m2 s1, whereas in mature epidermis, Dcw=(2.5{+/-}0.7)x1012 m2 s1, at least an order of magnitude lower. Relative to the diffusion coefficient of CF in water, these represent reductions by approximately 1/15 and 1/195, respectively. The low value for mature epidermis is correlated with a suberin-like permeability barrier that was detected with either autofluorescence or berberine staining. This study provides a quantitative estimate of the permeability of plant cell walls to small organic acidsa class of compounds that includes auxin and other plant hormones. These measurements constrain models of solute transport, and are important for quantitative models of hormone signalling during plant growth and development. 10.1093/jxb/erm155}, author = {Kramer, Eric M. and Frazer, Nicholas L. and Baskin, Tobias I.}, citeulike-article-id = {2584028}, citeulike-linkout-0 = {http://dx.doi.org/10.1093/jxb/erm155}, citeulike-linkout-1 = {http://jxb.oxfordjournals.org/cgi/content/abstract/58/11/3005}, citeulike-linkout-2 = {http://view.ncbi.nlm.nih.gov/pubmed/17728296}, citeulike-linkout-3 = {http://www.hubmed.org/display.cgi?uids=17728296}, day = {1}, doi = {10.1093/jxb/erm155}, journal = {J. Exp. Bot.}, keywords = {approximation, auxin, level, measurement, root}, month = {August}, number = {11}, pages = {3005--3015}, posted-at = {2008-03-25 09:50:39}, priority = {2}, title = {Measurement of diffusion within the cell wall in living roots of Arabidopsis thaliana}, url = {http://dx.doi.org/10.1093/jxb/erm155}, volume = {58}, year = {2007} }

TY - JOUR ID - citeulike:2584028 L3 - citeulike-article-id:2584028 N2 - To quantify the diffusion constant of small molecules in the plant cell wall, fluorescence from carboxyfluorescein (CF) in the intact roots of Arabidopsis thaliana was recorded. Roots were immersed in a solution of the fluorescent dye and viewed through a confocal fluorescence microscope. These roots are sufficiently transparent that much of the apoplast can be imaged. The diffusion coefficient, Dcw, of CF in the cell wall was probed using two protocols: fluorescence recovery after photobleaching and fluorescence loss following perfusion with dye-free solution. Diffusion coefficients were obtained from the kinetics of the fluorescent transients and modelling apoplast geometry. Apoplastic diffusion constants varied spatially in the root. In the elongation zone and mature cortex, Dcw=(3.2{+/-}1.4)x1011 m2 s1, whereas in mature epidermis, Dcw=(2.5{+/-}0.7)x1012 m2 s1, at least an order of magnitude lower. Relative to the diffusion coefficient of CF in water, these represent reductions by approximately 1/15 and 1/195, respectively. The low value for mature epidermis is correlated with a suberin-like permeability barrier that was detected with either autofluorescence or berberine staining. This study provides a quantitative estimate of the permeability of plant cell walls to small organic acidsa class of compounds that includes auxin and other plant hormones. These measurements constrain models of solute transport, and are important for quantitative models of hormone signalling during plant growth and development. 10.1093/jxb/erm155 IS - 11 JF - J. Exp. Bot. EP - 3015 TI - Measurement of diffusion within the cell wall in living roots of Arabidopsis thaliana VL - 58 SP - 3005 KW - approximation KW - auxin KW - level KW - measurement KW - root AU - Kramer, Eric AU - Frazer, Nicholas AU - Baskin, Tobias PY - 2007/08/01/ UR - http://dx.doi.org/10.1093/jxb/erm155 ER -