Some characteristics of the sucrose uptake system of excised tomato roots

Abstract

Uptake of sucrose by excised tomato roots showed saturation kinetics and could proceed against an internal sucrose concentration of approximately 0.046 M. It was inhibited by a number of compounds structurally related to sucrose and was largely but not totally dependent on respiration. It is concluded that sucrose was taken up mainly by an active process and to a lesser extent also by a passive process. Low pH markedly increased the uptake and sodium ions, and ouabain had no appreciable effect.

Sugar unloading in roots of Ricinus communis L.

“…optimal at an acidic pH (Chin et al, 1981 ;Hendrix, 1984). The possibility tbat tbis was an efTect due to tbe proton bufferitig capacity of tbe cell wall was iScussiON discounted since the pH optimum of insoluble acid Sugar accumulation into root tips of Ricinus sbows invertase (Cbapleo & Hall, 1989fl) is similar to that of exogenous sucrose hydrolysis by root tips (Fig.…”

Valine uptake in the tap root of sugar beet: a comparative analysis with sucrose uptake

“…At the cell level, absorption of sucrose and amino acids has been studied on various experimental models, leaf fragments (Cheung and Nobel, 1973;Delrot et al, 1980;Despeghel and Delrot, 1983), coleoptiles (Etherton and Rubinstein, 1978), cotyledons (Komor et al, 1977;Hutchings, 1978), roots (Chin et al, 1981), and pulvinar tissues (Racusen and Galston, 1977;Otsiogo-Oyabi and Roblin, 1985).…”