The influence of 2,4-dichlorophenoxyacetic acid on cell cycle Kinetics and Sister-Chromatid Exchange Frequency in Garlic (Allium sativum L.) Meristem Cells

Doležel, Jaroslav; Lucretti, Sergio; Novák, František

doi:10.1007/bf02892785

Cited by 22 publications

(5 citation statements)

References 17 publications

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“…It is possible that growth regulators act as mutagens . The synthetic auxin, 2,4dichlorophenoxyacetic acid (2,4-D), has been shown to increase the frequency of blue to pink mutations in the Tradescantia stamen hair system (Dolezel & Novak, 1984) and to induce significant increases in the frequency of sister chromatid exchanges in root-tip cells of Allium sativum (Dolezel et al ., 1987) . However, there is a paucity of examples of this kind and most evidence points to growth regulators influencing somaclonal variation during the culture phase through their effects on (1) cell division (Gould, 1984), (2) the degree of disorganised growth (Karp, 1992) and (3) selective proliferation of specific cell types (Ghosh & Gadgil, 1979) .…”

Section: Introductionmentioning

confidence: 99%

Somaclonal variation as a tool for crop improvement

Karp

1995

Euphytica

171

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Somaclonal variation is a tool that can be used by plant breeders . The review examines where this tool can be applied most effectively and the factors that limit or improve its chances of success . The main factors that influence the variation generated from tissue culture are (1) the degree of departure from organised growth, (2) the genotype, (3) growth regulators and (4) tissue source. Despite an increasing understanding of how these factors work it is still not possible to predict the outcome of a somaclonal breeding programme . New varieties have been produced by somaclonal variation, but in a large number of cases improved variants have not been selected because (1) the variation was all negative, (2) positive changes were also altered in negative ways, (3) the changes were not novel, or (4) the changes were not stable after selfing or crossing . Somaclonal variation is cheaper than other methods of genetic manipulation. At the present time, it is also more universally applicable and does not require `containment' procedures . It has been most successful in crops with limited genetic systems and/or narrow genetic bases, where it can provide a rapid source of variability for crop improvement .

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Section: Introductionmentioning

confidence: 99%

Somaclonal variation as a tool for crop improvement

Karp

1995

Euphytica

171

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“…i n culture . Therefore, the only means used so far was direct chromosomal analysis (e .g ., Bhojwani, 1980;Dolezel et al ., 1987 ;Dolezel & Novak, 1984 ;Hussey & Falavigna, 1980 ;Nandi et al ., 1977 ;Seo & Kim, 1988) . Isozyme analysis has provided a reasonably precise and quantitative measure of genetic divergence between and within populations, by allowing the direct study of gene products (Tanksley & Orton, 1983) .…”

Section: Discussionmentioning

confidence: 99%

In vitro propagation and germplasm cold-storage of fertile and male-sterile Allium trifoliatum subsp. hirsutum

Viterbo¹,

Altman²,

Rabinowitch

1994

Genet Resour Crop Evol

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Procedures for in vitro clonal propagation and for cold-storage of propagules were developed for fertile and male-sterile genotypes of Allium trifoliatum subsp . hirsutum, var. hirsutum and var . sterile, respectively . Highest rate of shoot multiplication was achieved from basal leaf and umbel explants on a modified BDS medium supplemented with 9 mg/l benzyladenine . Naphthalene acetic acid reduced the propagation rate, and was not required for shoot multiplication . The resulting shoots were rooted in an indole butyric acid-supplemented medium, and bulbing occurred upon exposure to a 16 h photoperiod . The small dormant bulbs were transplanted into potting mixture and sprouted after termination of dormancy, resulting in phenotypically-normal plants . No significant differences, in either shoot regeneration or plant establishment, were found between fertile and male-sterile genotypes .Basal leaf explants of in vitro grown plantlets were stored at 4-6°C for up to 16 months . Standard medium, or modified media containing 0 .4 to 10 .0% sucrose or 1 to 10 mg/I paclobutrazol, were used in storage experiments . Eighty to 100% and 70% survival rates, were recorded after 8 and 16 months cold-storage, respectively, in a 10% sucrose medium . Following their transfer to standard culture conditions, these explants regenerated plants which were phenotypically similar to those developed in the potting mixture .Isozyme polymorphism of 13 proteins was used to assess the genetic stability of cold-stored explants . Considerable differences in zymograms were found between the fertile and the sterile varieties . However, no differences in isozyme profiles were detected between the control field-grown plants, and those which were established from in vitro -stored leaf base explants . The only exception were plantlets exposed to a high paclobutrazol concentration in storage . The latter exhibited a doubling in the alcohol dehydrogenase profile .

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“…The considerable phenotypic variability between the regenerants (Table 1) may suggest the occurrence of genetic modifications during callus formation and regeneration of adventitious shoots as found in other species (GHAWLA 1988). Although vitreous shoots are considered to result from physiological disorders only, broad-leaf phenotypes may involve genetic modifications, which are known to be caused by extensive exposure of Allium tissues to mutagenic levels of 2,4-D (DOLEZEL et al 1987). The results suggest that picloram can also cause some genetic changes (Table 1).…”

Section: Discussionmentioning

confidence: 99%

Plant Regeneration from Callus Cultures of Allium trifoliatum subsp. hirsutum and Assessment of Genetic Stability by Isozyme Polymorphism

Viterbo¹,

Rabinowitch

Altman³

1992

Plant Breeding

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Plant regeneration from callus cultures of Allium trifoliatum subsp. hirsutum fertile accession F-370, was studied as a means for clonal multiplication and germplasm storage of Allium spp. Callus was induced on in vitro-cultured basal leaf explants. Best proliferation was obtained on modified BDS medium supplemented with (mg/l): 0.75 picloram, 2.0 benzyl adenine, and 900 casein hydrolysate. Shoot and root organogenesis were obtained in 3 to 5 month old subcultured calli, on BDS or MS medium supplemented with (mg/i): either 0.03 picloram or no auxin, 2 BA or 2-isopentenyladenine, and 900 casein hydrolysate. Direct bulb formation, without shoot elongation, occurred on BDS medium with 10 mg/l IBA. Under these conditions, callus formation and organogenesis were not obtained with A. trifoliatum subsp. hirsutum var. sterile, a male-sterile genotype.Most regenerants were phenotypically normal, but some abnormal shoots were also observed, i.e. shoots with vitrified or extremely broad leaves. Isozyme polymorphism analysis of seven proteins in the latter regenerants, and in several callus cultures, revealed significant deviation from the original pattern in esterase, 6-phosphogluconate dehydrogenase and superoxide dismutase. No such deviations were detected in normal regenerated plants.

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The influence of 2,4-dichlorophenoxyacetic acid on cell cycle Kinetics and Sister-Chromatid Exchange Frequency in Garlic (Allium sativum L.) Meristem Cells

Cited by 22 publications

References 17 publications

Somaclonal variation as a tool for crop improvement

Somaclonal variation as a tool for crop improvement

In vitro propagation and germplasm cold-storage of fertile and male-sterile Allium trifoliatum subsp. hirsutum

Plant Regeneration from Callus Cultures of Allium trifoliatum subsp. hirsutum and Assessment of Genetic Stability by Isozyme Polymorphism

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