Chromosome endoreduplication as a factor of salt adaptation in Sorghum bicolor Article First Online: 30 May 2006 Received: 11 May 2005 Accepted: 28 June 2005 DOI:
Cite this article as: Ceccarelli, M., Santantonio, E., Marmottini, F. et al. Protoplasma (2006) 227: 113. doi:10.1007/s00709-005-0144-0 Summary.
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. Keywords: Chromosome endoreduplication; Feulgen cytophotometry; Root cortex cell; Salt adaptation; Sorghum bicolor.
Correspondence and reprints: Dipartimento di Biologia Cellulare e Ambientale, Università di Perugia, Via A. Pascoli, 06123 Perugia, Italy.
References Amzallag, GN 1996 Transmissible reproductive changes following physiological adaptation to salinity in Sorghum bicolor New Phytol 132 317 332 CrossRef Google Scholar Amzallag, GN 1998 Induced modifications in reproductive traits of salt-treated plants of Sorghum bicolor Israel J Plant Sci 46 1 8 Google Scholar Amzallag, GN 1999 Individuation in Sorghum bicolor: a self-organized process involved in physiological adaptation to salinity Plant Cell Environ 22 1389 1399 CrossRef Google Scholar Amzallag, GN, Lerner, HR 1994 Adaptation versus pre-existing resistance: an intergenotype analysis of the response of Sorghum bicolor to salinity Israel J Plant Sci 42 125 141 Google Scholar Amzallag, GN, Lerner, HR, Poljakoff-Mayber, A 1990 Induction of increased salt tolerance in Sorghum bicolor by NaCl pretreatment J Exp Bot 41 29 34 Google Scholar Amzallag, GN, Seligman, H, Lerner, HR 1993 A developmental window for salt-adaptation in Sorghum bicolor J Exp Bot 44 645 652 Google Scholar Amzallag, GN, Nachmiasa, A, Lerner, HR 1998 Influence of the mode of salinization on the reproductive traits of the field-grown progeny in Sorghum bicolor Israel J Plant Sci 46 9 16 Google Scholar Bhaskaran, S, Smith, RH, Schertz, K 1983 Sodium chloride tolerant callus of Sorghum bicolor Z Pflanzenphysiol 112 459 463 Google Scholar Catarino, FM 1965 Salt water, a growth inhibitor causing endopolyploidy Port Acta Biol Ser A 9 131 152 Google Scholar Catarino, FM 1968 Endopoliploidia e differenciacao. Inducao experimental de endopoliploidia em Lobularia maritima e Bryophyllum crenatum Port Acta Biol Ser A 11 1 218 Google Scholar Cavallini, A, Natali, L, Giordani, T, Durante, M, Cionini, PG 1996 Nuclear DNA changes within Helianthus annuus L.: variation in the amount and methylation of repetitive DNA within homozygous progenies Theor Appl Genet 92 285 291 CrossRef Google Scholar Ceccarelli, M, Giordani, T, Natali, L, Cavallini, A, Cionini, PG 1997 Genome plasticity during seed germination in Festuca arundinacea Theor Appl Genet 94 309 315 CrossRef Google Scholar Ceccarelli, M, Esposto, MC, Roscini, C, Frediani, M, Gelati, MT, Cavallini, A, Giordani, T, Pellegrino, RM, Cionini, PG 2002 Genome plasticity in Festuca arundinacea: direct response to temperature changes by redundancy modulation of interspersed DNA repeats Theor Appl Genet 104 901 907 CrossRef PubMed Google Scholar Cionini, PG 2004 Genome plasticity as a factor of environmental adaptation in plant species Recent Res Dev Genet Breeding 1 259 268 Google Scholar Cullis, CA 1999 The environment as an active generator of adaptive genomic variation Lerner, HR eds. Plant responses to environmental stresses Marcel Dekker New York 129 160 Google Scholar
D’Amato F (1965) Endopolyploidy as a factor in plant tissue development. In: White PR, Grove AR (eds) Proceedings of the International Conference on Plant Tissue Culture. Berkeley, pp 449–462
Koyro, HW 1997 Ultrastructural and physiological changes in root cells of Sorghum plants induced by NaCl J Exp Bot 48 693 706 Google Scholar Koyro, HW 2002 Ultrastructural effects of salinity in higher plants Läuchli, A Lüttge, U eds. Salinity: environment, plants, molecules Kluwer Dordrecht 139 157 Google Scholar Kramer, D 1983 The possible role of transfer cells in the adaptation of plants to salinity Physiol Plant 58 549 555 CrossRef Google Scholar Mansour, MMF, Salama, KHA, Al-Mutawa, MM 2003 Transport proteins and salt tolerance in plants Plant Sci 164 891 900 CrossRef Google Scholar Meyer, G, Schnitt, JM, Bohnert, HJ 1990 Direct screening of a small genome: estimation of the magnitude of plant gene expression changes during adaptation to high salt Mol Gen Genet 224 347 356 CrossRef PubMed Google Scholar Natali, L, Giordani, T, Cionini, G, Pugliesi, C, Fambrini, M, Cavallini, A 1995 Heterochromatin and repetitive DNA frequency variation in regenerated plants of Helianthus annuus L. Theor Appl Genet 91 395 400 CrossRef Google Scholar Peschke, VM, Phillips, RL 1992 Genetic implications of somaclonal variation in plants Adv Genet 30 41 75 CrossRef Google Scholar Pikaard, CS 2001 Genomic changes and gene silencing in polyploids Trends Genet 17 675 677 CrossRef PubMed Google Scholar Price, HJ, Johnston, JS 1996 Influence of light on DNA content of Helianthus annuus Linnaeus Proc Natl Acad Sci USA 93 11264 11267 CrossRef PubMed Google Scholar Soltis, PS, Soltis, DE 2000 The role of genetic and genomic attributes in the success of polyploids Proc Natl Acad Sci USA 97 7051 7057 CrossRef PubMed Google Scholar Tester, M, Davenport, R 2003 Na + tolerance and Na + transport in higher plants Ann Bot 91 503 527 CrossRef PubMed Google Scholar