Determination of Auxin-Dependent pH Changes in Coleoptile Cell Walls by a Null-Point Method

Determination of Auxin-Dependent pH Changes in Coleoptile Cell Walls by a Null-Point Method.

The present debate on the validity of the "acid-growth theory" of auxin (indole-3-acetic acid, IAA) action concentrates on the question of whether IAA-induced proton excretion into the cell wall is quantitatively sufficient to provide the shift in pH that is required to explain IAA-induced growth (see D.L. Rayle, R.E. Cleland [1992] Plant Physiol 99:1271-1274 for a recent apologetic review of t...

Auxin-induced Changes in Avena Coleoptile Cell Wall Composition.

Sugar and uronic acid residues were derived from wall polysaccharides of oat (Avena sativa, var. Victory) coleoptiles by means of 2 N trifluoroacetic acid, 72% sulfuric acid, or enzymic hydrolysis. The products of hydrolysis were reduced and acetylated to form alditol acetates which were analyzed using gas chromatography. Time-course studies of auxin-promoted changes in various wall fractions i...

Phenolic acids in wheat coleoptile cell walls.

The phenolic constituent of nonvascular cell walls of wheat (Triticum aestivum L.) coleoptiles, which yields vanillin upon nitrobenzene oxidation, is not lignin as I previously claimed. It seems to be mainly ferulic acid bonded to carbohydrate, probably by an ester linkage. The acid is associated with a fraction of the wall rich in arabinose and xylose, although it is not known whether it is es...

Sugar composition of oat-coleoptile cell walls.

Auxin-induced changes in the molecular weight of hemicellulosic polysaccharides of the Avena coleoptile cell wall

The average molecular weight of the water soluble hemicelluloses (hemicellulose B) of the Avena coleoptile cell wall was determined by gel permeation chromatography (GPC) and viscometry. Analysis of the neutral sugar composition of henucellulose B eluted from a GPC column (Sepharose 4B) indicated that it consists of /J-glucan with a high molecular weight and arabinoxylan with a low molecular we...