Fe-EDTA Reduction in Roots of Plantago lanceolata by a NADH-dependent Plasma Membrane-bound Redox System

Formation of Root Epidermal Transfer Cells in Plantago

“…Reduction of ferric Fe by roots of Plantago is increased upon Fe deficiency by induction of an NADH-Fe chelate reductase in the peripheral cell layer (Schmidt et al, 1990;Schmidt, 1994a). This finding is confirmed in the present investigation by an 8-to 9-fold stimulation of the reduction activity in roots of P. lanceolata (Table I).…”

Fe3+-Chelate Reductase Activity of Plasma Membranes Isolated from Tomato (Lycopersicon esculentum Mill.) Roots

“…This value agrees well with similar analyses of PM Fe-chelate reductases in tomato and Plantago (9,24) but was higher than the optimum determined for intact roots (6,22). However, the optimum determined for intact roots reflects the optimum for just the Fe3" reduction, whereas the pH analysis in detergent-permeabilized vesicles reflects a compromise of both substrates [NADH and Fe3"(citrate3-)2].…”

“…Roots of-Fe tomatoes reduced Fe3+-chelates at a 4 to 7 times higher rate than did roots of +Fe plants (9,10). Recently, NADHdependent reduction of Fe3+-chelates by PM isolated from the roots of tomato (9,10) and Plantago lanceolata (24) was reported. Consistent with the whole root studies, PM isolated from -Fe tomato plants demonstrated higher Fe-chelate reductase activities than PM isolated from +Fe plants (9,10).…”

The pH Requirement for in Vivo Activity of the Iron-Deficiency-Induced "Turbo" Ferric Chelate Reductase (A Comparison of the Iron-Deficiency-Induced Iron Reductase Activities of Intact Plants and Isolated Plasma Membrane Fractions in Sugar Beet)

“…Vol. 11 O, 1996 Briiggemann andMoog, 1989) and subsequently in strategy I plants such as tomato (Buckhout et al, 1989;Briiggemann et al, 1990;Holden et al, 1991Holden et al, , 1992Valenti et al, 1991), bean (Schmidt and Janiesch, 1991b), Plantago (Schmidt et al, 1990), Geum urbanum (Schmidt and Janiesch, 1991a), Vigna unguiculata (Briiggemann et al, 1993), and Arabidopsis tkaliana (Moog et al, 1995). However, the PM from Fe-deficient plants usually exhibits FC-R activities biochemically similar to those of PM from control plants.…”