THE PLANT-ROOT AS AN OSMO-DIFFUSIVE CONVERTER OF FREE-ENERGY

This work focuses on the maize root as a one-membrane osmo-diffusive c onverter of free energy. Energy expenditures of the root on water tran sport by radial route as well as on xylem water uptake, occurring acco rding to the principle of osmotic root pressure, are analyzed. The so- called practical method of osmo-diffusive energy conversion (Kargol 19 90, 1993) and experimental data taken from the work by Steudle et al. (1987) were employed, including coefficients of filtration ((L) over b ar(pr)), reflection (<(sigma)over bar>) and permeation (<(omega)over b ar>)) of the maize root treated as a one-membrane model system. It is shown a.o. that the energy efficiency of the root does not depend (wit hin a certain concentration interval) on the concentration of a given solute in solution into which the root is placed. This suggests a cert ain independence of environmental conditions. The efficiency is differ ent for different dissolved substances contained in the solution.