Chromosome endoreduplication as a factor of salt adaptation in Sorghum bicolor.
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.
Ceccarelli
M
M
Dipartimento di Biologia Cellulare e Ambientale, Università di Perugia, Perugia, Italy.
Santantonio
E
E
Marmottini
F
F
Amzallag
G N
GN
Cionini
P G
PG
D000222:Adaptation, Physiological / Q000187:drug effects*; D002467:Cell Nucleus / Q000378:metabolism; D032461:Chromosomes, Plant / Q000187:drug effects* / Q000235:genetics; D018744:DNA, Plant / Q000378:metabolism; D020440:Gene Duplication / Q000187:drug effects*; D018517:Plant Roots / Q000187:drug effects; D012965:Sodium Chloride / Q000494:pharmacology*; D045868:Sorghum / Q000187:drug effects* / Q000235:genetics*
D018744:DNA, Plant; D012965:Sodium Chloride