COMPARTMENTAL REDISTRIBUTION AND LONG-DISTANCE TRANSPORT OF ABSCISIC-ACID (ABA) IN PLANTS AS INFLUENCED BY ENVIRONMENTAL-CHANGES IN THE RHIZOSPHERE - A BIOMATHEMATICAL MODEL
S. Slovik et al., COMPARTMENTAL REDISTRIBUTION AND LONG-DISTANCE TRANSPORT OF ABSCISIC-ACID (ABA) IN PLANTS AS INFLUENCED BY ENVIRONMENTAL-CHANGES IN THE RHIZOSPHERE - A BIOMATHEMATICAL MODEL, Journal of Experimental Botany, 46(289), 1995, pp. 881-894
Based on experimental data obtained in earlier studies on membrane per
meabilities of abscisic acid (ABA) for Cortex and stele cells of roots
and on measured compartmental pH shifts after onset or release of dif
ferent types of soil-borne stresses, a biomathematical model was devel
oped which permits computer analysis of the dynamics of compartmental
ABA distribution within different root tissues (cortex, stele) and the
ir compartments (apoplast, cytosol, vacuole), and in the xylem sap of
the root stele, Metabolism and conjugation of ABA and its export from
roots via the xylem and its import into roots via phloem sap flow are
also taken into consideration, We want to know which soil-borne stress
es can biophysically provoke a root-to-shoot signal of ABA. In this co
mmunication we describe the biomathematical structure of the root mode
l and present all necessary morphological (volumes, surfaces etc.) and
physiological (pH, membrane conductances etc.) parameters of unstress
ed roots, This root model and an available leaf model are integrated t
o a plant model (rosette plant), Simulations reveal the fundamental ro
le of the stele tissues, the rhizospheric ABA concentration and the AB
A synthesis in roots (root-to-shoot communication), The shoot-to-root
communication strongly depends on ABA synthesis in leaves, but hardly
on ABA redistribution effects after stress-induced compartmental pH-sh
ifts in leaves.