The Effect of Addition of Sucrose on the Energy Status and the Trans-Root Electrical Potential Difference of Excised Maize Roots

We present the results of our attempt to determine the metabolicstatus of excised maize roots (Zea mays L. cv. ZP SC704) andits effect on the trans-root electrical potential difference(TRP). Besides the electrical potential difference, we measuredoxygen consumption, sugar content and ¹⁴C-sucrose uptake anddistribution by supplying the cut end of root with sucrose.Our experiments show that sucrose added to the cut end of excisedroots was taken up by them, increasing the sugar content andmetabolic activity of such roots. These sugar-supplemented rootsexhibited approximately 60% higher internal sugar content andrespiratory rates, and 30% higher magnitudes of TRP, comparedto sugar-depleted roots. By optimizing the ionic composition(pH, K⁺, Ca²⁺) and sucrose concentration of the upper solutionfor sucrose uptake and translocation, maintenance of energeticstatus and transport functions of the excised root, closer tothat existing in situ, was ensured. (Received July 4, 1994; Accepted October 17, 1994)