The elasticity of the root cell wall significantly decreased in the salt-sensitive
cultivars, whereas that in the salt-tolerant cultivars was maintained at
a high level. Root extension and the differences among cultivars were largely
dependent on elastic extension, which accounts for 1/2 to 2/3 of the total
extension. Plastic extension of the root cell walls did not change across
the treatments and cultivars. The significant decrease in cell wall elasticity
in the root elongation region was one of the factors that depressed root
growth in salt-sensitive cultivars under the saline condition. Cell wall
elasticity was positively correlated with the relative pectin and hemicellulose
I contents and negatively correlated with the relative cellulose content.
Chemical composition of the cell wall were related with the salt tolerance
in wheat cultivars.
.png) |
| Figure. Creep extension curves of root cell walls during the extension (5 min) and shrinkage (5 min) of salinity tolerant wheat cultivars (Xinchun-31, JS-7) and the sensitive ones (Yongliang-15, GS-6058) under 0 (black lines) and 80 (grey lines) mM NaCl treatments. The schematic illustration is based on the extension curve of Yongliang-15. E and η describe the resistances of the material to the stretch force (P0) in elastic and plastic extending process, respectively. Footnotes of 0-3 indicate the different extension stages. |