Diversity in root apoplastic barrier deposition in salt treated wild and
domesticated barley seedlings
Abstract
Salt stress causes changes in root apoplastic barriers, such as the
endodermis and the exodermis, and these changes are associated with
variation in abiotic stress tolerance. We explored variation in root
apoplastic barrier traits, O2 consumption and root and
shoot Na+ and K+ content in a
diverse collection of commercial and wild barley accessions subjected to
non-saline (control) and saline treatments. Lignin and suberin
deposition in endo- and exo-dermal cell walls varied between the
accessions and in response to salt treatments. Twenty-two wild barley
accessions formed an exodermis in response to salt treatments, whereas
the commercial barley cultivar Barke did not develop an obvious
exodermis. Accessions with pronounced root barrier deposition tended to
have lower O2 consumption relative to the accessions
with less obvious barriers. Treatment with abscisic acid enhanced
suberisation and lead to a pronounced formation of an exodermis in wild
barley accessions, whereas treatment with an ethylene precursor had no
obvious effect on suberisation. Principal component analysis revealed
associations between suberin deposition, root and shoot
Na+ and K+, and root respiration.
The variation in root apoplastic barrier traits within the barley
accessions represents a useful resource for future crop breeding to
improve environmental stress tolerance.