biologia plantarum

Biologia plantarum 44:247-252, 2001 | DOI: 10.1023/A:1010203510065

Effect of Water Deficit and Membrane Destruction on Water Diffusion in the Tissues of Maize Seedlings

I.F. Ionenko¹, A.V. Anisimov¹

¹ Institute of Biochemistry and Biophysics, Kazan Scientific Centre of Russia Academy of Sciences, Kazan, Russia

We investigated diffusion of water in maize seedlings (Zea mays L. cv. Dnepropetrovskaya) following addition of polyethylene glycol (PEG) 6000 (osmotic potential -0.1 and -0.3 MPa) to the root medium by NMR method with pulsed gradient of magnetic field. Diffusion coefficients of different water phases in plant tissues (water of apoplast and vacuoles, water transported through the membranes) have been estimated from multicomponent decays of echo amplitude. Different signs of changes of water diffusion coefficients of fast and slow components of diffusional echo decay in roots and leaves under the influence of PEG-induced water deficits were shown. It has been supposed that under water deficit a sharing of water flows takes places through the different pathways (apoplastic, symplastic and transmembrane). In roots, 1-h water deficit increased the rate of fast diffusing water (water of apoplasm, vacuoles and, perhaps, water contained in intercellular endoplasm system), and decreased the rate of slowly diffusing water (water passing across the membranes). A long-term water deficit increased to a small extent the rate of water transmembrane transfer in root tissue. Leaf response to water stress was in the intensification of rate of transmembrane water transport that could be connected with the expression of water channels, and in the decrease of apoplastic water flow and flow along endoplasm. The possibility of estimation of plant tissue (membrane) integrity on the basis of diffusional data has been demonstrated.

Keywords: apoplastic water transport; symplastic water transport; water permeability; Zea mays

Subjects: apoplastic water transport; maize; membrane destruction, water diffusion; permeability and diffusion, water; symplastic and apoplastic water transport; water deficit, membrane destruction, water diffusion; water diffusion, membrane destruction; Zea mays

Published: June 1, 2001Show citation