Character of growth correlations in Arabidopsis abruptus mutant with deteriorated auxin transport

Abstract

Internodes of inflorescence stems of wild-type (wt) A. thaliana and abruptus (abr) mutant with deteriorated polar auxin transport had similar axial growth gradients, elongating by their 5–6 mm long subnodal part. Pin-formed shoots of abr plants had less steep axial growth gradient. Basipetal growth retardation was accompanied by cell-wall elastic and plastic extensibility decrease and cell-wall peroxidase activity increase. So, the growth retardation can be caused by cell-wall stiffening resulted from peroxidase-dependent oxidative cross-linking of polymers. Inflorescence stems of abr had evidently overlapping growth periods of successive internodes which suggested participation of polar auxin transport in the correlative inhibition of internodes growth.

Keywords:

Arabidopsis thaliana, pinoid mutant, polar auxin transport, growth correlations, cell-wall extensibility, peroxidases