Journal Article

Water and solute permeabilities of Arabidopsis roots in relation to the amount and composition of aliphatic suberin

Ranathunge, Kosala, Schreiber, Lukas

2011

Overview

Although it is implied that suberized apoplastic barriers of roots negatively correlate with water and solute permeabilities, direct transport measurements across roots with altered amounts and compositions of aliphatic suberin are scarce. In the present study, hydroponically grown Arabidopsis wild types (Co18 and Co10) and different suberin mutants with altered amounts and/or compositions (horst, esb1-1, and esb1-2) were used to test this hypothesis. Detailed histochemical studies revealed late development of Casparian bands and suberin lamellae in the horst mutant compared with wild types and esb mutants. Suberin analysis with gas chromatography and mass spectrometry (GC-MS) showed that the horst mutant had ~33% lower amounts of aliphatic monomers than Co18 and Co10. In contrast, enhanced suberin mutants (esb1-1 and esb1-2) had twice the amount of suberin as the wild types. Correlative permeability measurements, which were carried out for the first time with a root pressure probe for Arabidopsis, revealed that the hydraulic conductivity (Lp r ) and NaCI permeability (P sr ) of the whole root system of the horst mutant were markedly greater than in the respective wild types. This was reflected by the total amounts of aliphatic suberin determined in the roots. However, increased levels of aliphatic suberin in esb mutants failed to reduce either water or NaCI permeabilities below those of the wild types. It was concluded that the simple view and the conventional assumption that the amount of root suberin negatively correlates with permeability may not always be true. The aliphatic monomer arrangement in the suberin biopolymer and its microstructure also play a role in apoplastic barrier formation.

• Publisher: Oxford University Press
• Subject: anatomy & histology / Arabidopsis / Arabidopsis - anatomy & histology / Arabidopsis - chemistry / Arabidopsis - physiology / Biological and medical sciences / biopolymers / Cell membranes / Cell walls / chemistry / Corn / correlation / Endodermis / Fatty acids / Fundamental and applied biological sciences. Psychology / gas chromatography / Hydraulic conductivity / Lipids / Lipids - chemistry / Lipids - physiology / mass spectrometry / metabolism / mutants / Permeability / physiology / Plant Roots / Plant Roots - anatomy & histology / Plant Roots - chemistry / Plant Roots - physiology / Plants / Pyrenes / Pyrenes - metabolism / RESEARCH PAPER / Research Papers / Root pressure / root systems / roots / sodium chloride / Solutes / suberin / Sulfonic Acids / Sulfonic Acids - metabolism / Water / Water - metabolism