Chromosome endoreduplication as a factor of salt adaptation in Sorghum bicolor

Protoplasma. 2006 May;227(2-4):113-8. doi: 10.1007/s00709-005-0144-0. Epub 2006 May 30.

Abstract

Nuclear DNA amounts were measured by Feulgen cytophotometry in Sorghum bicolor cv. 610 plants early exposed to 150 mM NaCl, a treatment known to induce an increased tolerance to salinity in plants carrying this genotype. In salt-treated plants, the percentages of 8C, 16C, and 32C nuclei in roots in the primary state of growth were 21.9%, 13.3%, and 4.3%, respectively. By contrast, in nonsalinized plants, only 3.5% of the nuclei had an 8C content and no higher DNA contents were observed. The salt treatment induced chromosome endoreduplication during the differentiation of cells in the root cortex, where 41.2% of the cells displayed a DNA content higher than 4C (versus 1.3% in control plants). No enhancement of endopolyploidy was observed in cells of the root vascular cylinder or the leaves of the salt-treated plants. In another S. bicolor genotype (DK 34-Alabama), noncompetent for salt adaptation, the same NaCl treatment did not induce chromosome endoreduplication in root cortex cells. Endopolyploidy may be considered as a part of the adaptive response of S. bicolor competent genotypes to salinity.

MeSH terms

  • Adaptation, Physiological / drug effects*
  • Cell Nucleus / metabolism
  • Chromosomes, Plant / drug effects*
  • Chromosomes, Plant / genetics
  • DNA, Plant / metabolism
  • Gene Duplication / drug effects*
  • Plant Roots / drug effects
  • Sodium Chloride / pharmacology*
  • Sorghum / drug effects*
  • Sorghum / genetics*

Substances

  • DNA, Plant
  • Sodium Chloride