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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Biologia plantarum 43 (2000), S. 133-136 
    ISSN: 1573-8264
    Keywords: apomixis ; cluster analysis ; St. John's wort
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A karyotype study was made on Hypericum perforatum using plants differentiated in vitro with different ploidy level. The chromosomes of this species are small, morphologically similar, median and submedian. In the basic chromosome set the most distinguishable is chromosome number 1 which was subjected to detail analysis. It was found that there are two types of this chromosome which contribute differentially in diploid, triploid and tetraploid plants.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Theoretical and applied genetics 101 (2000), S. 46-50 
    ISSN: 1432-2242
    Keywords: Key words Hypericum ; FISH ; 5S/25S rRNA genes ; Karyotype evolution ; Polyploidy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  The chromosomal positions of the 5S/25S rRNA genes of Hypericum perforatum (2n=32), H. maculatum (2n=16) and H. attenuatum (2n=32) were comparatively determined by FISH, and six, three and seven chromosome pairs of the respective karyotypes were subsequently distinguished. The rDNA loci between H. perforatum and H. maculatum seem to be identical (with respect to the ploidy difference), indicating that H. perforatum probably arose by autotetraploidization from an ancestor closely related to H. maculatum. The positional differences between the 5S rRNA gene loci of H. perforatum and H. maculatum on the one hand and H. attenuatum on the other argue against a previous hypothesis according to which H. perforatum originated from a remote interspecific hybridization between H. maculatum and H. attenuatum.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 10 (1990), S. 245-251 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Callus cultures of two tetraploid plant of Matricaria recutita L. were initiated from leaves and cultured on LINSMAIER-SKOOG culture medium supplemented with 0.01 mg · 1-1 IAA or 3.00 mg · 1-1 2, 4-D for three years. The relationship between mitotic activity and growth of calli was studied. The time at which mitotic activity began in both cultures was different. In the callus culture cultivated on the medium with IAA the maximum mitotic activity was observed on the 14th to 17th day of subculture. In the one cultivated on the medium with 2,4-D, the increase of mitotic activity was observed earlier and corresponded with the beginning of exponential growth. In addition of total mitotic activity individual mitotic phases have also been evaluated. Most mitotically active cells in both cultures were in prophase. Their courses were similar to those of total mitotic activity. Metaphase and telophase stages were present in low frequency. Anaphase occured rarely. The functional dependences of mitotic activity and growth were characterized by appropriate mathematical models.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 14 (1994), S. 267-274 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The hypericin content of in vitro regenerated plants of Hypericum perforatum L. was determined by spectrophotometry. A significant variability of some of the morphological characters, of the biomass production and the hypericin formation was found within the somaclones of the same genetic origin and among the regerants of different genotypes. The concentration of BAP which promoted the shoot differentiation did not affect the hypericin content and the gland density. New information on the ultrastructure of hypericin-containing multicellular glands is presented here.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 11 (1991), S. 331-334 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The morphogenetic capacity of Digitalis purpurea L. leaf explants and callus cultures has been studied. The promoting growth of calli was induced by the presence of exogenously applied auxins and cytokinins in the ratio 2:1. Bud and shoot differenatiation occurred in leaf explants and callus cultures of the 2nd subculture under the influence of 1.00 to 5.00 mg·1-1 N67hyphen;[2-Isopentenyl] adenine. The regeneration protocol described provides 7 to 10 plantlets per leaf explant. The results are compared with the effect of other cytokinins in Digitalis purpurea and a related Digitalis lanata species.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 12 (1992), S. 445-452 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Seedings of Hypericum perforatum L. have produced multiple shoots on RM medium supplemented with 2.22 or 4.40 μM BAP. Regenerants were evaluated for variability in several morphological characteristics. A comparison with the control showed significant differences in fresh and dry matter and height of plants, but did not effect branching and the number of glands containing dianthrones.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: An altered ploidy level was observed in plants regenerated by adventitious shoot formation from seedlings of Hypericum prformatum L. (2n = 4x = 32). Among the somaclones of the Ro generation, the presence of diploids (2n = 2x = 16), triraploids (2n = 3x = 24), tetraploids (2n = 4x = 32) and mixoploids was detected. Cytogenetic analyses of the R1 and R2 progenies showed that the chromosomal instability of the Ro somaclones was transferred onto the next generation.While almost all the seed progeny of diploids (100% in R1 and 94% in R2) progenies showed that the chromosomal instability of the Ro somaclones was transferred onto the next generations.While almost all the seed progeny of diploids (100% in R1 and 94% in R2) and more than 60% of tetraploids (61% in R1 and 73% in R2) retained their chromosome number, cytogenetic diversity was observed in the progeny of triploids, mixoploids and some tetraploids.Somaclones and their offspring were analyzed for hypericin content. Statistical evaluation showed a correlation between hypericin content and ploidy during a two-year cultivation of R0 somaclones and in their R1 and R2 progenies.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Berlin : Wiley-Blackwell
    Acta Biotechnologica 19 (1999), S. 163-169 
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The morphogenetic response of Hypericum perforatum seedlings to different auxin and cytokinin concentrations was studied. A stimulation of the concentration-dependent rooting ability was observed under the influence of indole-3-acetic acid and indole-3-butyric acid. Rooting was not enhanced by the effects of 2,4-dichlorophenoxyacetic acid and 1-naphtaleneacetic acid. Differentiated roots were isolated and cultured in liquid media with the same combination of growth-promoting auxins. Chromosome counts in root tip cells after long-term cultivation indicated a high degree of chromosomal instability. Multiple shoot formation occurred under the influence of 6-benzylaminopurine and kinetin. Adenine and 6-(γ,γ-dimethylallylamino)-purine did not stimulate shoot differentiation. No differences in the morphogenetic response to auxins and cytokinis were detected between diploid and tetrapoloid plants.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 0138-4988
    Keywords: Life Sciences ; Life Sciences (general)
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: The effects of the non-ionic surfactant, Pluronic F-68, on the growth of shoots regenerated from seedlings (14 days post-germination) of Hypericum perforatum L. were studied. The supplementation of agar-solidified medium with 0.001% (w/v) of Pluronic increased the mean fresh weight of the regenerants after 60 days by 40% and the mean number of plant regenerants recovered per seedling by 34%; a less pronounced increase in the number of regenerants occurred with 0.01% (w/v) of the surfactant. By contrast, the mean fresh weight of the regenerants cultured in the presence of 0.1% (w/v) Pluronic F-68 was 15% lower than untreated controls, although the mean number of regenerants per seedling remained unaltered. The growth of seedling leaf-derived Hypericum callus after 60 days was unaffected by all the concentrations of Pluronic tested. However, there was a tendency for callus cells grown in the presence of Pluronic to be more highly pigmented with anthocyanins. The cultivation of leaf explants with 0.001% or 0.01% (w/v) Pluronic did not affect either the mean fresh weight of the regenerants or the mean number of regenerants per explant. However, decreases in both the mean fresh weight and the mean number of regenerants (both 33.0% lower than the control) occurred following the cultivation with 0.1% (w/v) Pluronic.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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