Related Experiment Video
Updated: Aug 8, 2026

Measuring Fluxes of Mineral Nutrients and Toxicants in Plants with Radioactive Tracers
Published on: August 22, 2014
Abscisic Acid transport coefficients of phaseolus root systems
E L Fiscus1, F R Stermitz, L G Amoros
1United States Department of Agriculture-Agricultural Research Service, Crops Research Laboratory, Colorado State University, Fort Collins, Colorado 80523.
Abstract:
Diffusive and convective transport coefficients of Phaseolus vulgaris L. cv. Ouray root systems for abscisic acid for (ABA) were measured. The convective coefficient (reflection coefficient or osmotic efficiency factor) sigma was determined to be 0.96 for ABA while the diffusive coefficient, omega, was found to be 1.44 x 10(-11) mole per square centimeter per second per bar. Steady-state concentrations of ABA in the root system exudates were not achieved until at least three hours after the applications suggesting either a slow saturation of binding sites or equilibration with tissues surrounding the xylem.
Related Concept Videos
Water and Mineral Acquisition
Short-distance Transport of Resources
Carrier-Mediated Transport
Active transport involves two types of membrane-spanning transporters: uptake and efflux. Uptake transporters are expressed in the small...
The Apoplast and Symplast
Pore Transport and Ion-Pair Transport
Pore transport, also known as convective transport, is a process where small molecules like urea, water, and sugars rapidly cross cell membranes as though there were channels or pores in the membrane. Although direct microscopic evidence is limited but the concept of pores or channels is widely accepted based on physiological evidence. Despite the lack of direct microscopic...
Phloem and Sugar Transport

