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1

In vitro manipulation of cucumber [Cucumis sativus L.] pollen and microspores: isolation procedures, viability tests, germination, maturation

100%
Vizintin L., Bohanec B.
Acta Biologica Cracoviensia. Series Botanica
|
2004
|
tom 46
The distribution of plastids at the time of microspore and pollen grain development in Gagea lutea (L.) Ker.-Gaw. was analyzed using electron microscopy. It was shown that plastids are not transmitted to the forming generative cell of this species during microspore division. At the vacuolate microspore stage, preceding division, the microspore nucleus takes an acentric position and the plastids gather at the opposite side of the cell. In the highly polarized microspore at prophase of mitosis, all plastids are aggregated at one side of the nucleus, whereas mitochondria are dispersed throughout the cytoplasm. Numerous profiles of endoplasmic reticulum (ER) are present between the clustered plastids. Some of the ER profiles are attached by their ends to the outer membrane of plastid envelopes and join the distant plastids. The outer membrane of the microspore plastids may form long and thin evaginations contacting with other plastids. Microtubules are visible in plastid aggregations occasionally. In dividing microspores, long ER cisterns surround the area of the mitotic spindle and separate it from the region containing plastids. There are no plastids in the young generative cell: all plastids remain clustered in the region of the microspore that now forms the vegetative cell of the bicellular pollen grain. Later the connections between plastids and ER cisterns gradually disappear and plastids disperse in the cytoplasm of the whole vegetative cell. The results of our study are not sufficient to define the mechanism causing selective aggregation of plastids at the vegetative pole of the Gagea microspore, nor to say whether the microtubular cytoskeleton plays a role. However, the participation of ER in these processes, at least in holding the special arrangement of microspore plastids, seems certain.
2

Improvements of doubled haploid production protocol for white cabbage (Brassica oleracea var. capitata L.)

81%
Rudolf Pilih, K., Potokar U. K., Bohanec B.
Folia Horticulturae
|
2018
|
tom 30
|
nr 1
3

Embryological analysis of in vitro cultured unpollinated ovules of Allium cepa L.

80%
Musial K., Bohanec B., Przywara L.
Acta Biologica Cracoviensia. Series Botanica. Supplement
|
1999
|
tom 41
|
nr 1
4

Gynogenesis in onion [Allium cepa L.] - embryological study

80%
Musial K., Bohanec B., Przywara L.
Acta Biologica Cracoviensia. Series Botanica. Supplement
|
2000
|
tom 42
|
nr 1
5

Interphase structure of endoreduplicated nuclei in diploid and tetraploid Brassica oleracea L.

80%
Sesek P., Kump B., Bohanec B.
Acta Biologica Cracoviensia. Series Botanica
|
2005
|
tom 47
|
nr 1
Endoreduplication of nuclei is a common phenomenon in plants. Cells with multiplied DNA content are usually termed endopolyploid or polysomatic. The study was aimed at clarifying the chromosomal status of endoreduplicated nuclei. So far it has been generally assumed that endoreduplicated nuclei represent a form of polyploidy. We propose a distinction between true polyploid nuclei, possessing multiple sets of chromosomes, and chromosomes formed within endoreduplicated nuclei. We supposed that chromosomes within endoreduplicated nuclei are not separated, as in true polyploids, but rather are bound together. To clarify these two alternatives, we subjected interphase nuclei exhibiting different degrees of endoreduplication and ploidy to fluorescent in situ hybridization, using diploid and tetraploid cabbage root tips containing nuclei of four different sizes (2C-16C or 4C-32C, respectively) as revealed by flow cytometry. Nuclei were hybridized with an rDNA probe (pTA71), which showed four rDNA hybridization sites on diploid metaphase chromosomes. The number of hybridization sites was constant for both diploid and tetraploid samples (3-6 per diploid and 7-12 per tetraploid nuclei) irrespective of endoreduplicated nuclear size. The results showed more signals only in the tetraploid compared to the diploid genotype, but not between different nuclear sizes within a genotype of the same ploidy. We suggest that these results indicate that chromosomes within endoreduplicated nuclei are actually bundles of sister chromatids. The consequences of this understanding of the bundled chromosomal status of endoreduplicated nuclei are discussed.
6

Intra- and interpopulational variation in the amounts of nuclear DNA in the moss Pleurozium schreberi

80%
Bohanec B., Kuta E., Przywara L.
Cellular and Molecular Biology Letters
|
2002
|
tom 07
|
nr Suppl.
7

A protocol for quantitative analysis of green fluorescent protein-transformed plants, using multiparameter flow cytometry with cluster analysis

80%
Bohanec B., Luthar Z., Rudolf K.
Acta Biologica Cracoviensia. Series Botanica
|
2002
|
tom 44
Green fluorescent protein (GFP) is a particularly important reporter gene used in various transformation studies. Expression of GFP fluorescence can be visually monitored under UV or blue excitation in transformed cells. However, quantifications of fluorescence expression using fluorimetric methods are limited to average expression in tissues and cannot be assessed in single cells. An improved protocol to determine quantitative single cell fluorescence was developed using GFP-transformed tobacco leaf protoplasts measured by multiparameter flow cytometry. It was shown that a Percoll density gradient or sucrose flotation are essential for optimal separation. Fluorescent protoplasts and those expressing only background autofluorescence were successfully separated using three-parameter analysis. For clustered subpopulations, relative fluorescence intensity and proportions of cells with expressed or non-expressed fluorescence can be measured. Further applications of this novel procedure are discussed.
8

The effect of exogenous and endogenous phytohormones on the in vitro development of gametophyte and sporophyte in Asplenium nidus L.

71%
Menendez V., Abdul Y., Bohanec B., Lafont F., Fernandez H.
Acta Physiologiae Plantarum
|
2011
|
tom 33
|
nr 6
The fern Asplenium nidus L. is in great demand as an ornamental plant. The aim of this work was to investigate the influence of phytohormones in promoting a gametophytic and sporophytic growth in homogenized sporophytes tissue. Exogenous application of 0.5 and 5 µM N⁶-benzyladenine, 0.05 and 0.5 µM indole-3-acetic acid (IAA), and 0.3 and 3 µM gibberellic acid (GA3) favoured sporophyte regeneration, whereas gametophyte regeneration took place when plant material was cultured in a hormone-free liquid MS medium. The endogenous contents of the auxin IAA, the cytokinins trans-zeatin, transzeatin riboside, dihydrozeatin, dihydrozeatin riboside, isopentenyladenine and isopentenyladenosine, and the gibberellins GA₁, GA₃, GA₄, GA₇, GA₉ and GA₂₀ in growing gametophytes and sporophytes were evaluated. Similar levels of the auxin and cytokinins and qualitative differences in the gibberellins were found between both generations.
9

High variability of nuclear DNA content in cultivars and natural populations of Poa pratensis L. in relation to morphological characters

71%
Murovec J., Kastelec D., Vilhar B., Cop J., Bohanec B.
Acta Biologica Cracoviensia. Series Botanica
|
2009
|
tom 51
|
nr 2
45-52
Kentucky bluegrass is a facultative apomict which is propagated from seeds of variable genetic origins, ploidy levels and nuclear DNA contents. This study analyzes the variability of relative nuclear DNA content among cultivars and natural populations, and examines whether this variability is correlated with morphological traits. Relative nuclear DNA content (an indirect measure of chromosomal variability) was determined in 281 plants from 28 accessions (17 cultivars, 11 populations) using flow cytometry of DAPI-stained nuclei. The same plants were also measured for leaf area and stomatal length. Variation of measured relative DNA content between the studied accessions was very high (5.5-fold). Intra-accession variation was very high in six accessions, even though three of these were cultivars. Relative nuclear DNA content was correlated with stomatal length but not with leaf area. The lack of correlation with leaf area might explain why high intra-accession variability of nuclear DNA content was found in released cultivars that had passed uniformity testing during the registration procedure. We suggest that nuclear DNA content measurement should be made part of the cultivar registration process
10

Karyology and amounts of nuclear DNA in Luzula L.- A genus with holokinetic chromosomes

71%
Dubas E., Kuta E., Bohanec B., Vizintin L., Przywara L.
Cellular and Molecular Biology Letters
|
2002
|
tom 07
|
nr Suppl.
11

Erratum to: effect of sucrose on shoot regeneration in Agrobacterium transformed Hypericum perforatum L. roots

61%
Vinterhalter B., Zdravkovic-Korac S., Mitic N., Bohanec B., Vinterhalter D., Savic J.
Acta Physiologiae Plantarum
|
2016
|
tom 38
|
nr 10
12

Effect of sucrose on shoot regeneration in Agrobacterium transformed Hypericumperforatum L. roots

61%
Vinterhalter B., Zdravkovic-Korac S., Mitic N., Bohanec B., Vinterhalter D., Savic J.
Acta Physiologiae Plantarum
|
2015
|
tom 37
|
nr 02
The aim of the present study was to investigate the effect of sucrose on shoot regeneration potential in Hypericum perforatum L. roots obtained by Agrobacterium rhizogenes transformation. The morphological evaluation of transgenic roots grown on media supplemented with sucrose (0.5, 1, 2, 4, 6 and 8 %) indicated that both genotype and sucrose concentration significantly affected root elongation and branching, as well as shoot regeneration. For two of five analyzed clones, lower sucrose concentrations (up to 2 %) led to intensive shoot regeneration, while the other three clones intensified shoot development only at elevated sucrose concentrations (4 %). For all clones, concentrations above 4 % had a deleterious effect on both root and shoot development. Genetic characterization of regenerated shoots revealed that all tested clones were diploid with an average of 0.670 ± 0.002 pg of DNA per nucleus, with no significant differences between transgenic and non-transformed plants and, according to PCR, with integrated A. rhizogenes rolA, -B, -C and -D genes. Real-time RT-PCR confirmed the expression of rolA, -B and -C, while expression of the rolD gene was not detected. Differences were detected in the absolute amounts of transcripts between analyzed clones, with the highest levels of expression for all three analyzed rol genes in a clone previously defined as having high root differentiation and less effective shoot regeneration potential. The observed variations in morphogenesis potential could be attributed to different levels of expression of integrated rolA, -B and -Cgenes; while sucrose additionally pointed out these trends.
13

Genomic in situ hybridization in viviparous onions [Allium x proliferum and Allium x bulbiliferum]

61%
Puizina J., Klein F., Bohanec B., Javornik B., Maluszynska J., Papes D., Schweizer D.
Prace Naukowe Uniwersytetu Śląskiego w Katowicach
|
1998
|
tom 1696
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