Biopolym. Cell. 1998; 14(4):298-319.
Genome variability in plant somatic cells. 4. Variability in the process of dedifferentiation and callus formation in vitro
1Kunakh V. A.
  1. Institute of Molecular Biology and Genetics, NAS of Ukraine
    150, Akademika Zabolotnoho Str., Kyiv, Ukraine, 03680

Abstract

Peculiarities of the genome, variations upon induction of the dedifferentiation and callus formation events have been reviewed. Role of the genotype and the genome state in cells of the original explant, nutrient medium stimuli, determinants, mechanisms and possible ways to control these variations have been discussed. Initiation of the dedifferentiation processes and further cell proliferation was shown to suggest the reprogramming of the genome, «juvenilization» of its state. Genome regressive evolution in the course of the development of the dedifferentiation program was hypothesized. Capacity for such evolution seems to underly the differentiation–dedifferentiation–differentiation developmental cycle peculiar to many plants. Existence of such a cycle, its potential to be control-liable both in nature and experiment appear to question the concept about the programmed number of the cell cycles, the irreversibility of ageing, tile fatality of the programmed cell death and. apoptosis. Utmost importance and actuality of the studies on molecular mechanisms of the dedifferentiation and juvenilization processes in plants has been emphasized. Author believes that this would allow better understanding of the fundamental biological mechanisms involving ageing and death.

References

[1] Kunakh VA. Genome variability in plant somatic cells. 3. Callus formation in vitro. Biopolym Cell. 1997; 13(5):362-71.
[2] Krepko NP. Plant regeneration. M.; L.: Izd AN SSSR, 1950; 676 p.
[3] Butenko RG. Isolated tissue culture and physiology of plants morphogenesis. M.: Nauka, 1964. 272 p.
[4] KOrdium EL, Nedukha EM, Sidorenko PN. Structural and functional characterization of plant cells during differentiation and dedifferentiation. K.: Naukova Dumka. 1980. 116 p.
[5] Sarnatskaya VV. Physiological aspects of tumor growth of plants. K.: Naukova, Dumka, 1993. 152 p.
[6] Gautheret RJ. La culture in vitro: bref apercu historique. R Acad agr France. 1980; 66(8): 621-7.
[7] Partanen CR. Plant tissue culture in relation to developmental cytology. Int Rev Cytol. 1963;15:215-43.
[8] Reinert J. Neue Ergebnisse und Probleme mit Gewebekulturen aus h?heren Pflanzen. Ber Dtsch Bot Ges. 1965;78(11):1-11.
[9] Zossimovich VP, Kunakh VA. Frequency, type and origin of chromosome aberrations in plant tissue cultures. Genetika. 1975; 11(6):37-46.
[10] Frolova LV, Shamina ZB. [Cytogenetic characteristics of legume family plant tissue cultures]. Tsitol Genet. 1974;8(5):413-8.
[11] Shamina ZB. Genetic variability of plant cells in vitro. Plant Cell Culture. Kiev Naukova Dumka. 1978: 80-93.
[12] Shamina ZB. Genetic variation in somatic plant cells populations in culture: Thesis. ...dr biol. nauk. Leningrad, 1988. 34 p.
[13] Frolova LV. Features of cultured cells populations. Plant Cell Culture. M.: Nauka, 1981: 5-16.
[14] D'Amato F. Spontaneous mutations and somaclonal variation. NIK I. Techn. and in vitro Cult. Plant Improv.: Proc Int Symp. (Viena, 19-23 Aug., 1985). Viena, 1986: 3-10.
[15] Orton TJ. Somaclonal variation: theoretical and practical considerations. Gene Manipul. Plant Improv.: 16th Stadler Genet. Symp. New York; London, 1984: 427-68.
[16] Orton IJ. Genetic instability in celery tissue and cell cultures. Iova State J Res. 1987; 61(4): 481-98.
[17] Mestre J-C, P?tiard V. La nature de la variabilit? des cellules v?g?tales en culture; les diverses causes possibles de son expression. Acta Bot Gallica. 1985;132(3-4):67-78.
[18] Sidorov VA, Sidorova NV. Somaclonal variability as a sourceof genetic diversity in plants. Tsitol Genet. 1987; 21(3):230-6.
[19] Sidorov VA. Plant Biotechnology. Cellular selection. Kiev: Naukova Dumka, 1990. 280 p.
[20] Morrison RA, Whitaker R, Evans DA. Somaclonal variation: its genetic basis and prospects for crop improvemenl. Opportunities Phytochem. Plant Biotechnol.: Proc. 27th Annu Meet.Phytochem. Soc. N. Amer. (Tampa, Fla, June 21-26. 1987». New York; London, 1988: 1-18.
[21] Hartmann C, Winfield M, Corre F, Davey MR, Rode A, Karp A. A comparative study of the mitochondrial genome organization in in vitro cultures of diploid, tetraploid, and hexaploid Triticum species. Theor Appl Genet. 1996;93(5-6):968-74.
[22] Wersuhn G. Obtaining Mutants from Cell Cultures. Plant Breeding. 1989;102(1):1–9.
[23] He Qi-gian, Lin Xin-zhi. CpDNA and mtDNA variability in tissue culture of alfalfa. Acta agron sin. 1994; 20(1): 33-8.
[24] Mardamshin AG, Matveeva EV. The abundance of various low-molecular-weight mitochondrial DNAs in pea (Pisum sativum L.) tissues. Fiziologiia rasteniy. 1997; 44(3):445-8.
[25] Kunakh VA. Genome variability of plant somatic cells. 1. Variability during ontogenesis. Biopolym Cell. 1994; 10(6):5-35.
[26] Kunakh VA. Genome variability in plant somatic cells. 2. Natural variability. Biopolym Cell. 1995; 11(6):5-40.
[27] Meyer Y. L'induction du d?veloppement mitotique chez les protoplastes de m?sophylle de Tabac cultiv?s «in vitro» : contr?le hormonal. Acta Bot Gallica. 1985; 132(1): 97-107.
[28] Botella MA, Quesada MA, Medina MI, Pliego F, Valpuesta V. Induction of a tomato peroxidase gene in vascular tissue. FEBS Lett. 1994;347(2-3):195-8.
[29] Smith CA, Davies E. Wound-induced electrical signaling and systemic gene expression in plants. Plant Physiol. 1994; 105(1), Suppl: 67.
[30] Zeleneva IV, Polikarpochkina RT, Reymers FE et al. [Enzyme systems callus and suspension culture in comparison with the starting material, interstices of intact plants]. Dokl Akad Nauk SSSR. 1979; 248(2): 509-12.
[31] Swarnkar PL, Bohra SP, Chandra N. Biochemical studies on initiation of callus in Solanum surattense. J Plant Physiol. 1986;126(2-3):293–6.
[32] Xinyu Wang, Shiyu Zhang. Changes in the composition of isoenzymes in explants of young inflorescences of wheat and barley by dedifferentiation. J. Lanzhou Univ. 1991; 27(2):108-12.
[33] Buiatti M, Durante M, Geri G et al. Amplificazione nelle prime fasi della sdiffereziazione di midollo di Nicotiana glauca. Boll Zool. 1975; 42(4): 438-9.
[34] Le Tran B, Kohler KH. Untersuchungen uber die DNA-Synthese wahrend der Fruhphase der Kallusbildung bei Zea mays Wurzeln. Biochem Physiol Pflanzen. 1976; 170(3):189—200.
[35] De Martinis P, Brunori A, Devreux M. DNA synthesis in dedifferentiating pith cells of Nicotiana tabacum. G Bot Ital. 1977; 111(4-5): 255.
[36] Chriaui D. Donnees nouvelles sur les mecanismes de a dedifferenciation chez les Vegetaux. Arch Anat Microsc Morphol Exp. 1983; 72(3): 248-9.
[37] Masuda K, Kikuta Y, Fujino K, Okazava Y. Preferential synthesis of mitochondrial DNA during the initial stage of tissue growth in potato explant cultures. J Fac Agr Hokkaido Univ. 1994; 66(1):13-25.
[38] Hakui Y, Nakamura C. MtDNA variation in auxin stable cell culture of tobacco. Sci Repts Fac Agr Kobe Univ. 1991; 19(2): 107-12.
[39] Cionini PG, Zolfino C, Cavallini A. Extra DNA synthesis in the dedifferentiating cells ofVicia faba roots. Protoplasma. 1985;124(3):213-8.
[40] Chen C-C, Lee F-M, Kao Y-Y. Endoreduplication in leaf protoplasts of haploid Nicotiana plumbaginifolia cultured in vitro . Genome. 1988;30(5):615-20.
[41] Pijnacker LP, Sree Ramulu K, Dijkhuis P, Ferwerda MA. Flow cytometric and karyological analysis of polysomaty and polyploidization during callus formation from leaf segments of various potato genotypes. Theor Appl Genet. 1989;77(1):102-10.
[42] Khrustaleva LI, Karlov GI. Kinetics of cell polyploidization in a primary callus of the different genotypes of Alfalfa. Tsitol Genet. 1995; 29(2):31-6.
[43] D?hrssen E, Sch?fer A, Neumann K-H. Qualitative Differences in the DNA of Some Higher Plants, and Aspects of Selective DNA Replication During Differentiation. Plant Syst Evol. 1979;95–103.
[44] Geri C, Durante M, Parenti R, Buiatti M. Amplificazione di DNA e fumorogenesi in tessuti vegetali. Atti Assoc Genet Ital. 1980; 26: 157-9.
[45] Sala F, Biasini MG. Heritable variability induced by the in vitro culture and genetic improvement of cultivated plants. Giornale botanico italiano. 1986;120(1-6):43–54.
[46] Escandon AS, Hopp HE, Hahne G. Differential amplification of five selected genes in callus cultures of two shrubby Oxalis species. Plant Sci. 1989;63(2):177–85.
[47] Kikuchi S, Takaiwa F, Oono K. Variable copy number DNA sequences in rice. Mol Gen Genet. 1987;210(3):373-80.
[48] Zheng KL, Castiglione S, Biasini MG, Biroli A, Morandi C, Sala F. Nuclear DNA amplification in cultured cells of Oryza sativa L. Theor Appl Genet. 1987;74(1):65-70.
[49] Cuzzoni E, Ferretti L, Giordani C et al. Extrachromosomal amplification of a repeated DNA sequence in cultured rice (Oryza saliva L.) cells. G Bot ital. 1989; 123(Suppl N 2):160-1.
[50] Deumling B, Clermont L. Changes in DNA content and chromosomal size during cell culture and plant regeneration of Scilla siberica: selective chromatin diminution in response to environmental conditions. Chromosoma. 1989;97(6):439–48.
[51] Rivin MJ, Gould A. Quantitative changes in the genome of maize embryos in tissue culture. Genetics (USA). 1984; 107(3.) pi 2:89-90.
[52] Cullis CA, Cleary W. DNA variation in flax tissue culture. Can J Gen Cytol. 1986;28(2):247–51.
[53] Cullis CA. The Generation of Somatic and Heritable Variation in Response to Stress. Am Nat. 1987;130(s1):S62.
[54] Cebrat S. Kierunkovosc rekombinacyjnych zmian wewnatrz-genomowych. Kosmos. 1987; 36(3):593-605.
[55] Gobel S, Brown PT, Lorz H. In vitro culture of Zeo mays L. and analysis of regenerated plants. Nucl. Techn and in vitro Cult. Plant Improv.: Proc. Int. Symp. (Vienna 19-23 Aug., 1985). Vienna, 1986: 21-27.
[56] Bashkite EA, Aleksandrushkina NI, Kirnos MD, Kiryanov GI, Vanyushyn BSh. Methylation of DNA in the tobacco cell culture suspension in processing phytohormones. Biol Nauki. 1980;4: 103-10.
[57] Jones LH, Scott TK. Transfer ribonucleic Acid modification and its relationship to tumorous and nontumorous plant growth. Plant Physiol. 1981;67(3):535-8.
[58] Vanyushin VF. DNA methylation and cell differentiation in higher plants. In: Plant growth and differentiation. M, 1981:176-92.
[59] Sjukste YC, Rashal ID. Action of cytokinins on the higher plant nuclei. Latv Zinatnu Akad Vestis. B. 1992; 7: 49-52
[60] Vyskot B, Gazdov? B, ?Irok? J. Methylation patterns of two repetitive DNA sequences in tobacco tissue cultures and their regenerants. Biol Plant. 1993;35(3):321–7.
[61] Kovalskaya VS, Sidorova NV. Methylation of genes rDNA i- callus tissue of winter wheat. Problems of the theory. i Prikl. Genetics in Kazakhstan: Materials. Rep Conf. (Alma-Ata, November 18-22., 1990). Alma-Ata. 1990: 62-3.
[62] Anderson S, Lewis-Smith AC, Smith SM. Methylation of ribosomal RNA genes inPetunia hybrida plants, callus cultures and regenerated shoots. Plant Cell Rep. 1990;8(9):554-7.
[63] Palmgren G, Mattsson O, Okkels FT. Specific Levels of DNA Methylation in Various Tissues, Cell Lines, and Cell Types of Daucus carota. Plant Physiol. 1991;95(1):174-8.
[64] Morrish FM, Vasil IK. DNA methylation and embryogenic competence in leaves and callus of napiergrass (Pennisetum purpureum Schum.). Plant Physiol. 1989;90(1):37-40.
[65] Brown PT, Kyozuka J, Sukekiyo Y, Kimura Y, Shimamoto K, L?rz H. Molecular changes in protoplast-derived rice plants. Mol Gen Genet. 1990;223(2):324-8.
[66] Phillips RI, Peschke VM. Discovery of Ac activity among progeny of tissue culture-derived maize plants. Plant Trans posable Llem.: Proc. Int. Symp. (Madison, Wise, Aug. 22-26, 1987). New York; London, 1988: 305-15.
[67] Hodgson J. Making the Transition to Applied Technology. Bio/Technology. 1990;8(8):714.
[68] Peschke VM, Phillips RL. Activation of the maize transposable element Suppressor-mutator (Spm) in tissue culture. Theor Appl Genet. 1991;81(1):90-7.
[69] Williams ME, Hepburn AG, Widholm JM. Somaclonal variation in a maize inbred line is not associated with changes in the number or location of Ac-homologous sequences. Theor Appl Genet. 1991;81(2):272-6.
[70] Vodkin LO. Transposable element influence on plant gene expression and variation. Biochem. Plants: Comprehensive treatise. San-Diego etc., 1989; Vol. 15: 83-132.
[71] McClintock B. The significance of responses of the genome to challenge. Dyn. Genome: Barbara McClintock's Ideas Century Genet. New York: Cold Spring Harbor Lab., 1992: 361-80.
[72] Butcher DN, Sogeke AK, Tommerup IC. Factors influencing changes in ploidy and nuclear DNA levels in cells from normal, crown-gall and habituated cultures ofHelianthus annuus L. Protoplasma. 1975;86(4):295–308.
[73] Dodds JH, Phillips R. DNA and histone content of immature tracheary elements from cultured artichoke explants. Planta. 1977;135(3):213-6.
[74] Yeoman MM, Evans PK, Naik GG. Changes in mitotic activity during early callus development. Nature. 1966;209(5028):1115–6.
[75] Reinert J, Kuster HJ. Diploide, chlorophyllhaltige Gewebekulturen aus Blattern von Crepis capillaris (L.) Wallr. Z Pflanzen Physiol. 1966; 54(3)213-222.
[76] Brossard D. N?oformation de Bourgeons V?g?tatifs et Inflorescentiels ? Partir de Disques Foliaires du Crepis capillaris L. Wallr. cultiv?s in vitro. Z Pflanzenphysiol. 1979;93(1):69–81.
[77] Nayak S, Sen S. Cytological and cytophotometric analysis of direct explant and callus derived plants of ornithogalum thyrsoides Jacq. Cytologia. 1991;56(2):297–302.
[78] Shimada T, Tabata M. Chromosome numbers in cultured pith tissue of tobacco. Jpn J Genet. 1967;42(3):195–201.
[79] Brossard D. Etude cytophotometrique des variations du con-tenu en DNA nucleaire au cours de la dedifferenciation de la moelle de Tabak (Nicotiana tabacum) cuitivee in vitro. Compt. rend. Acad. Sci. 1974; 278D(20):2517-20.
[80] Mikhailov OF, Bessonova VP. Some data on cytogenetic analysis of callus arising from pea cotyledons regenerating. In Probl. Oncology in plant teratomas. L.: Nauka, 1975:52-4.
[81] Negrutiu I, Beeftink F, Jacobs M. Arabidopsis thaliana as a model system in somatic cell genetics I. Cell and tissue culture. Plant Science Letters. 1975;5(5):293–304.
[82] Chand S, Roy SC. Study of callus tissues from different parts ofNigella sativa (Ranunculaceae). Experientia. 1980;36(3):305–6.
[83] Wenzler H, Meins F. Mapping regions of the maize leaf capable of proliferation in culture. Protoplasma. 1986;131(1):103–5.
[84] Ruiz ML, Vazquez AM. Chromosome number evolution in stem derived calluses ofHordeum vulgare L. culturedin vitro. Protoplasma. 1982;111(2):83–6.
[85] Amos JA, Scholl RL. Induction of Haploid Callus from Anthers of Four Species of Arabidopsis. Z Pflanzenphysiol. 1978;90(1):33–43.
[86] Nishibayashi S, Hayashi Y, Kyozuka J, Shimamoto k. Chromosome variations in protoplast-derived calli and in plants regenerated from the calli of cultivated rice. Oryza sativa L. Jpn J Genet. 1989;64(5):355–61.
[87] Kunakh VA, Alkhimova EG, Voityuk LI. Variability of the chromosome number in callus tissues and pea regenerants. Tsitol Genet. 1984; 18(1):20-5.
[88] Savchenko EK, Kunakh VA. Comparative characteristics of the tissue culture of two related maize lines differing in the amount of heterochromatin. Culture of plant cells and biotechnology. M.: Nauka, 1986: 214-218.
[89] Gubar EK. Kunakh VA. C-ban ding in Zea mays. Biotechnology in agriculture and forestry. Maize. Berlin; Heidelberg: Springer, 1994. Vol. 25: 366-381.
[90] Sacristan MD. Karyotypic changes in callus cultures from haploid and diploid plants of Crepis capillaris (L.) Wallr. Chromosoma. 1971;33(3):273-83.
[91] Mozafari J, Wolyn DJ, Ali-Khan ST. Chromosome doubling via tuber disc culture in dihaploid potato as determined by confocal microscopy. Plant Cell Reports. 1997;16(5):329–33.
[92] Kunakh VA, Levenko BA, Zassimovich VP. In vitro culture of Nicotiana tabacum anthers. II. Cytogenetic analysis of callus tissue derived from antihers at long-lasting passages. Tsitologiia. 1978;20(2):166-72.
[93] Smulders MJM, Rus-Kortekaas W, Gilissen LJW. Development of polysomaty during differentiation in diploid and tetraploid tomato (Lycopersicon esculentum) plants. Plant Science. 1994;97(1):53–60.
[94] Ito M, Stern H. Studies of meiosis in vitro. I. In vitro culture of meiotic cells. Dev Biol. 1967;16(1):36-53.
[95] Nehra NS, Kartha KK, Stushnoff C. Nuclear DNA content and isozyme variation in relation to morphogenic potential of strawberry ( Fragaria ? ananassa ) callus cultures . Can J Bot. 1991;69(2):239–44.
[96] Gubar EK, Kunakh VA. Karyotype variability of cultured Crepis cells (Crepis capillaris L. Wallr.). Genetika. 1992; 28(6):51-61.
[97] Kunakh VA. Features of structural mutagenesis in cultured plant cells populations. Uspekhi sovrem genetiki. Ed. NP. Dubinina. M.: Nauka, 1984; Iss 12:30-62.
[98] Toncelli F, Martini G, Giovinazzo G, Nuti Ronchi V. Role of permanent dicentric systems in carrot somatic embryogenesis. Theor Appl Genet. 1985;70(4):345-8.
[99] Li R, Stelly DM, Trolinder NL. Cytogenetic abnormalities in cotton (Gossypium hirsutum L.) cell cultures. Genome. 1989;32(6):1128-34.
[100] Oono K. Rice tissue cultures. Annu Rept Nat Inst Agrobiol Res. 1985; 1: 27-28.
[101] Kaneko K. Karyological studies on callus cells of Haplopappus gracilis. Kromosoma. 1974;95:2943-9.
[102] Kaneko K. Karyological studies in callus cells from stem, anther and ovule cuhures of Haplopappus gracilis. Bull Fukuoka Univ Educ Nat Sci. 1975; 25: 77-87.
[103] Ghosh PK, Chaterjee A. In vitro induction and maintenance of epicotyl derived callus culture of jute (Corchorus olitorius). Indian Biol. 1990; 22(1):38-39.
[104] Cherezhanova LV, Melik-Sarsikov OS, Ovchinnikova VN. Cytogenetic effect of sugars. Genetika. 1991;27(8):1372-8.
[105] Pijnacker LP, Ferwerda MA. Effect of sucrose on polyploidization in early callus cultures of Solanum tuberosum. Plant Cell Tiss Organ Cult. 1990;21(2):153–7.
[106] Martin T, Hellmann H, Schmidt R, Willmitzer L, Frommer WB. Identification of mutants in metabolically regulated gene expression. Plant J. 1997;11(1):53-62.
[107] Inz? D, Ferreira P, Hemerly A, Van Montagu M. Control of cell division in plants. Biochem Soc Trans. 1992;20(1):80-4.
[108] Katsy EI. Participation of auxin in the regulation of gene expression of bacteria and plants. Genetika. 1997; 33(5): 565-576.
[109] Chriqui D, Bercetche J. Facteurs hormonaux et ph?nom?nes amitotiques dans les explants v?g?taux cultiv?s in vitro. Acta Bot Gallica. 1985;132(3-4):152.
[110] Dolezhel I, Novak FI. Karyological change during dedifferentiation of garlic (Allium sativum L.). Plant cell culture and biotechnology. M.: Nauka. 1986: 20-25.
[111] Jha S, Sen S. Induction of mitosis in polytene nuclei and hormonal effect on nuclear changes during callus initiation in diploid Urginea indica Kunth. (liliaceae). Genetica. 1990;80(1):9–15.
[112] Giorgetti L, Pitto L, Tonelli MG. et al. Auxin induced formation of homeotic structures (anther- and pistil-like) in cultured expiants of different plant species. AtuVAssoc genet Itai. 1991; 37: 201-2.
[113] Kunakh VA, Zosimovich VP. Effect of kinetin on the frequency and types of chromosome aberrations in a tissue culture of Haplopappus gracilis. Genetika. 1977; 13(8):1355-65.
[114] Kunakh VA, Sidorenko YAL, Zosimovich VYa. Effect of kinetin on the reproduction of cells of different ploidy. Success of polyploidy. Kiev: Naukova Dumka, L., 1977;203-15.
[115] Bennici A, Caffaro L. Caryological behavior during the first phases of dedifferentiation and habituation in Nicotiana bigelovii. Protoplasma. 1985;124(1-2):130–6.
[116] Kunakh VA, Alpatova LK. The role of plant hormones in the variability of the chromosomes number in tissue culture Haplopappus gracilis. Dokl Akad Nauk SSSR. 1979; 245(4): 967-70.
[117] Kukakh VA, Zakhleniuk OV. Diploidization of the plant tissue culture using 5-uracil-thioreidoglucose(thiacyl). Dokl Akad Nauk SSSR. 1984;279(5):1241-4.
[118] Zakhlenyuk OV, Alekseyeva IV, Chernetskiy VP, Kunakh VA. Effect of kinetics and gliatsidina on tissue culture of tobacco. Plant cell culture and biotechnology. M., 1986: 37-41.
[119] Zakhlenyuk OV, Kunakh VA. Cytophysiological and cytogenetic effects of adenine derivatives in the tissue culture of Haplopappus gracilis. Fiziologiia rasteniy. 1987; 34(3):584-94.
[120] Kunakh VA, Adonin VI, Alpatova LK, Tkatchuk ZYu, Potopalsky AI. Cytogenetic after-effects of native and thiophosphamid modified RNAs on Haplopapus gracilis tissue culture. Tsitologiia. 1985; 27(4):476-87.
[121] Pavlova MK, Tymokhina NT, Piven MM. et al. Reproduction in vitro Beta vulgaris L. cell in planned modifications of culture medium. 3. Analysis of the effectiveness of medium components. Ukr Bot Zh. 1977; 34(3)252-6.
[122] Cionini PG, Bennici A, D’Amato F. Nuclear cytology of callus induction and developmentin vitro. Protoplasma. 1978;96(1-2):101–12.
[123] Kinoshita I, Sanbe A, Yokomura E-I. Increases in nuclear DNA content without mitosis in benzyladenine-treated primary leaves of intact and decapitated bean plants. J Exp Bot. 1991;42(5):667–72.
[124] Martins-Loucao MA, Catarino FM. Nuclear changes associated with callus induction in lobularia maritima. Bot Soc broter. 1981; 53(pt 2): 1211-21.
[125] Bogers R., Hooymans-Klappe HT., Libbenga K. The first cell cycle in explants from the mature root cortex of 7-day-old Pisum sativum. Plant Sci Lett. 1976;6(1):43–8.
[126] Therman E, Murashige T. Polytene chromosomes in cultured pea roots (Pisum, Fabaceae). Plant Systematics and Evolution. 1985;148(1-2):25–33.
[127] Furner IJ, King J, Gamborg OL. Plant regeneration from protoplasts isolated from a predominantly haploid suspension culture of Datura innoxia (Mill.). Plant Sci Lett.1978;11(2):169–76.
[128] Huang HC, Chen CC. Genome multiplication in cultured protoplasts of two Nicotiana species. J Hered. 1988; 79(1): 28-32.
[129] Roquin C, Amssa M, Henry Y et al. Origine des plantes polyploides obtenues par culture d'antheres. Analyse cytopho tometritiue in situ et in vitro des microspores de Petunia et de ble tendre. Pflanzetizucht. 1982; 89(4):265-77.
[130] Babaeva SA, Petrova TF, Gaponenko AK. Polyploidy and polyteny in Cereal cells cultured in vitro. Genetika. 1995; 31(5):678-3.
[131] Wang S, Hang A, Tsuchiya T. Chromosome studies of callus tissues and regenerated plants from an unfertilized ovule culture of sugarbeet. J Genet Breed. 1991; 45(3):161-8.
[132] Cionini PG, Bennici A, D'Amato F. Induzione delki proliferazione cellulare in esplanti da cotiledoni di Vicia faba coltivali in vitro: analisi citologica e densitometria del DNA. G bot ital. 1978; 112(4):314-5.
[133] Fasseas C, Bowes BG. Ultrastructural observations on proliferating storage cells of mature cotyledons of Phseolus vulgaris L cultured in vitro. Ann Bot. 1980; 46(2):143-52.
[134] Caffaro L, Dameri RM, Profumo P, Bennici A. Callus induction and plantlet regeneration inCichorium intybus L.: 1. A cytological study. Protoplasma . 1982;111(2):107–12.
[135] D'Amato F, Bennici A, Cionini PG et al. Nuclear fragmentation followed by mitosis as mechanism for wide: chromosome number variation in tissue cultures: its implications for plant regereration. Plant Cell Cult.: Results and Perspectives. Amsterdam etc., 1980; 67-72.
[136] Gaponenko AK, Petrova TF, Iskakov AR, Sozinov AA. Cytogenetics of in vitro cultured somatic cells and regenerated plants of barley (Hordeum vulgare L.). Theor Appl Genet. 1988; 75(6):905-11.
[137] Enikeev SG. On the plant cell division by scarring. Tr Kazan Inst og agricukt. 1967(1968). Iss 54:139-142.
[138] Chen CC, Kasha KJ, Marsolais A. Segmentation patterns and mechanisms of genome multiplication in cultured microspores of barley. Can J Genet Cytol. 1984;26(4):475–83.
[139] Gill BS, Kam-Morgan LNW, Shepard JF. Origin of chromosomal and phenotypic variation in potato protoclones. J Hered. 1986; 77(1): 13-6.
[140] Dhillon SS, Miksche JP. DNA Content and Heterochromatin Variations in Various Tissues of Peanut (Arachis hypogaea). Am J Bot. 1982;69(2):219-26.
[141] Kasuga II. Cytological study on regeneration of cultured cells in Angelica acutiloba. J Sci Hiroshima Univ. 1990; 23(1): 239-71.
[142] Meijer EGM, Keller WA, Simmonds DH. Cytological abnormalities and aberrant microtubule organization during early divisions in mesophyll protoplast cultures of Medicago sativa and Nicotiana tabacum. Physiol Plant. 1988;74(2):233–9.
[143] Thomas E, Bright SW, Franklin J, Lancaster VA, Miflin BJ, Gibson R. Variation amongst protoplast-derived potato plants (Solatium tuberosum cv. 'Maris Bard'). Theor Appl Genet. 1982;62(1):65-8.
[144] Sreenath HL, Jagadishchandra KS. In vivo and in vitro instability of B chromosomes in palmarosa grass ( Cymbopogon martinii var. motia ) . Genome. 1988;30(6):966–73.
[145] Ramulu KS, Dijkhuis P, Roest S. Patterns of phenotypic and chromosome variation in plants derived from protoplast cultures of monohaploid, dihaploid and diploid genotypes and in somatic hybrids of potato. Plant Science. 1989;60(1):101–10.
[146] Ronchi VN, Giorgetti L, Tonelli M, Martini G. Ploidy reduction and genome segregation in cultured carrot cell lines. I. Prophase chromosome reduction. Plant Cell Tiss Organ Cult. 1992;30(2):107–14.
[147] Ronchi VN, Giorgetti L, Tonelli M, Martini G. Ploidy reduction and genome segregation in cultured carrot cell lines. II. Somatic meiosis. Plant Cell Tiss Organ Cult. 1992;30(2):115–9.
[148] Feher F, Hangyel Tarczy M, Bocsa I, Dudits D. Somaclonal chromosome variation in tetraploid alfalfa. Plant Science. 1989;60(1):91–9.
[149] Franklin CI, Mott RL, Vuke TM. Stable ploidy levels in long-term callus cultures of loblolly pine. Plant Cell Rep. 1989;8(2):101-4.
[150] Kaishpadze KP. Localization and intensity of nucleic acid synthesis in isolated meristem stem apex vegetative tomato plants cells. Izv AN Gruz SSR. ser Biol. 1978; 4(3): 260-7.
[151] Kov?cs EI. Regulation of karyotype stability in tobacco tissue cultures of normal and tumorous genotypes. Theor Appl Genet. 1985;70(5):548-54.
[152] Olenov YuM. Cell heredity, cell differentiation and carcinogenesis as problems of evolutionary genetics. L.: Nauka, 1967. 310 p.
[153] McKnight TD, Fitzgerald MS, Shippen DE. Plant telomeres and telomerases. A review. Biochemistry (Mosc). 1997;62(11):1224-31.