Diffusion coefficient of the fluorescent dye CF (carboxyfluorescein) in cell wall

Value 32 µm^2/sec Range: ±14 µm^2/sec
Organism Thale cress Arabidopsis thaliana
Reference Kramer EM, Frazer NL, Baskin TI. Measurement of diffusion within the cell wall in living roots of Arabidopsis thaliana. J Exp Bot. 2007 58(11):3005-15 abstract & p.3011 left column 2nd paragraphPubMed ID17728296
Method 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, D(cw), 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."
Comments Abstract:"Apoplastic diffusion constants varied spatially in the root. In the elongation zone and mature cortex, D(cw)=(3.2±1.4)x10^-11 m^2 s^-1, whereas in mature epidermis, D(cw)=(2.5±0.7)x10^-12 m^2 s^-1, 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." p.3006 left column top paragraph:"That D (diffusion coefficient) cell wall is lower than D in water is attributable to the steric hindrance posed by cell wall constituents." See BNID 105032,105034
Entered by Uri M
ID 105033