Gradient of structural traits drives hygroscopic movements of scarious bracts surrounding Helichrysum bracteatum capitulum.

ABSTRACT:

Background and aims

The capitulum of Helichrysum bracteatum is surrounded by scarious involucral bracts that perform hygroscopic movements leading to bract bending toward or away from the capitulum, depending on cell wall water status. The present investigation aimed at explaining the mechanism of these movements.

Methods

Surface strain and bract shape changes accompanying the movements were quantified using the replica method. Dissection experiments were used to assess the contribution of different tissues in bract deformation. Cell wall structure and composition were examined with the aid of light and electron microscopy as well as confocal Raman spectroscopy.

Key results

At the bract hinge (organ actuator) longitudinal strains at opposite surfaces differ profoundly

SUBMITTER: Borowska-Wykret D 

PROVIDER: S-EPMC5604587 | biostudies-literature | 2017 Jun

REPOSITORIES: biostudies-literature