Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Pollination”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,117 records · Page 62Linked to original sources
PubMed2001

[Genetic diversity of natural populations of Arabidopsis thaliana (L.) Heynh. in Karelia].

The genetic structure of ten natural populations of Arabidopsis thaliana (L.) Heynh. at eight isozyme loci was studied. The populations were located in the northern part of the species range, 200 km from the north to the south along the Onega Lake coast in Karelia. Considerable genetic diversity (P99% = 43.7, Hobs = 0.003) was revealed that is not typical of populations of self-pollinating plant species. A direct correlation between the proportion of polymorphic loci and geographical latitude was shown (r = 0.68; P < 0.05). It is suggested that a high polymorphism level in Karelian Arabidopsis thaliana (L.) populations increasing from the south to the north is due to extreme environmental conditions in the northern part of the species range. The distribution of genetic diversity within and between populations is typical of self-pollinating species: the larger part of the total diversity resides among populations (GST = 0.583).

Alleles↗
PubMed2001

Population-level variation in the expression of heterostyly in three species of Rubiaceae: does reciprocal placement of anthers and stigmas characterize heterostyly?

Heterostyly (i.e., reciprocal placement of anthers and stigmas between two or three floral morphs) is hypothesized to enhance outcrossing and reduce selfing. However, few studies have documented reciprocity among individual plants; instead, mean anther and stigma heights for floral morphs are usually reported, masking interindividual variation. We measured eight floral dimensions for individuals in five populations of three heterostylous Rubiaceae. The three methods used to quantify reciprocity yielded different conclusions regarding the degree to which populations conformed to expectations for heterostylous plants. Only Psychotria poeppigiana had stigma and, to a lesser degree, anther heights in discrete classes. Variation among plants of Bouvardia ternifolia and Psychotria chiapensis yielded a continuum of anther and stigma heights across populations. Comparison of distances between stigma and anthers indicated that only flowers of B. ternifolia had, as expected, a constant value for this distance. Finally, regression relationships between anther and stigma heights and corolla length showed that only in one population each of B. ternifolia and P. poeppigiana, and in P. chiapensis, was distance between anthers and stigmas the same across the range of corolla sizes for both floral morphs. Variation among these species in expression of heterostyly was not clearly linked to phylogenetic relationship or pollinator syndromes. Two approach herkogamous (AH) species were studied for comparison. Flowers of Psychotria brachiata were consistently AH, but flowers of P. pittieri were highly variable. Determining fitness consequences of population-level variation in sexual systems requires studies linking floral morphology to pollinator behavior and pollen transfer.

Journal Article↗
PubMed2001

[Pollen surveys in Sapporo for 6 years during 1992 to 1997].

We carried out pollen surveys for 6 years from 1992 to 1997. The method of pollen survey studied was based on the standardization board of air born pollen survey and pollen information in Japan. The pollen samples were collected in Nishioka-area of Toyohira-ku, and Kawazoe-area of Minami-ku in Sapporo. As the pollen sample device. IS Rotary pollen trap was used at Nishioka-area during 1992 to 1994 and at Kawazoe-area in 1993, and Durham's pollen trap was used at Kawazoe-area during 1995 to 1997. The yearly pollen counts were highly fluctuated in trees, particularly Yew (Taxus spp.), Alder (Alnus spp.), Birch (Betula spp.), Pine (Pinus spp.), Fir (Abies spp.), than in Grasses (Gramineae) and Weeds (Polygonaceae, Plantago spp., Artemisia spp., Chenopodiaceae). In addition, the starting date of pollination was widely fluctuated year by year in trees. For instance, the pollen of Birch was confirmed on April 13 in 1993, as the first day in Nishioka-area, while it was on April 28 in 1994. It should be considered that the pollen counts and the starting date of pollination were highly dependent on the weather condition of the previous year and the current year.

Japan↗
PubMed2001

Implications of mating patterns for conservation of the endangered plant Eriogonum ovalifolium var. vineum (Polygonaceae).

Mating patterns have direct application to conservation because of their influence on structuring genetic diversity within and among populations and on maintaining that diversity over time. We measured population and family outcrossing rates, biparental inbreeding, correlation of outcrossed paternity, and inbreeding coefficients in six populations from throughout the ecological range of the endangered plant Eriogonum ovalifolium var. vineum using naturally pollinated families. The taxon was primarily outcrossed: population outcrossing rates averaged 0.80 (SE 0.03) and family outcrossing rates averaged 0.88 (SE 0.03); neither rate varied among populations. Five population rates were significantly different from 1 while family rates differed from 1 in only one population. We found high correlated outcrossed paternity and evidence for biparental inbreeding in five populations each. As expected from the predominantly outcrossed mating system, levels of diversity were high and inbreeding coefficients among maternal individuals were low (averaging -0.05, SE 0.12). Differences between inbreeding coefficients of progeny (average 0.21, SE 0.06) and mothers indicated selection against homozygous offspring. These results indicate that it is important to maintain large populations to prevent increases in inbreeding and to maintain pollinator communities to facilitate outcrossing.

Journal Article↗
PubMed2001

Development of sterile ovules on bisexual cones of Gnetum gnemon (Gnetaceae).

Angiosperms and Gnetales (Ephedra, Gnetum, Welwitschia) represent the only seed plants that regularly produce bisexual cones. Unfortunately, the fertility and function of ovules formed on bisexual cones of Gnetales have remained unclear. Some reports indicate that the ovules are sterile while others indicate that they may develop into seeds. This study demonstrates three different developmental patterns of ovules formed on bisexual cones of Gnetum gnemon. Type I ovules did not develop at all after pollination and represented the majority of ovules on each cone. Type II ovules enlarged slightly after pollination due to the enlargement of nucellar tissue. Type III ovules were typically found on the terminal whorl and developed into seed-like structures. The enlargement was due to proliferation of megagametophyte tissue. Sectioned material revealed that megagametophytes show altered development compared to those found in functional female ovules. None of the ovules studied contained embryos, and thus all were sterile. Densitometry of 4',6-diamidino-2-phenylindole (DAPI)- stained sections revealed that megagametophyte nuclei formed in the sterile ovules are unreduced (diploid) and thus do not form viable female gametes.

Journal Article↗
PubMed2001

Production of transgenic male sterile tobacco plants with the cDNA encoding a ribosome inactivating protein in Dianthus sinensis L.

The ribosome inactivating protein (RIP) gene from D. sinensis was used as a cytotoxin gene to induce male sterility in tobacco plants. The TA29 promoter, obtained by PCR amplification from tobacco, was fused to the RIP cDNA, and the chimaeric molecule was then introduced into tobacco plants by Agrobacterium-mediated transformation. Out of twenty-one independent transformants, twenty transgenic tobacco plants exhibited male sterility. Southern blot analysis revealed that four of the transgenic plants contained a single copy of the RIP gene, while the rest of the transgenic tobacco plants had two to four copies of the gene. The transgenic male sterile plants set seeds normally when pollinated with pollens from untransformed control plants, indicating that the RIP gene does not affect the pistil development. Furthermore, the seed yield of the transgenic plant was similar to that of the untransformed, self-pollinated control plant. A light microscopic observation of anther cross sections clearly showed that the tapetal tissue of the anther was selectively and completely destroyed causing male sterility. This study suggests that the RIP gene can be used as a cytotoxin gene for induction of male sterility in the plant.

DNA, Complementary↗
PubMed2001

Identification of S-genotypes by PCR-RFLP in breeding lines of Brassica.

We developed a molecular method for the identification of the S-alleles of Brassicaceae, which belongs to the inbred line. This method is quicker and more precise than the existing methods. The genotype of the S-allele for 20 S-haplotypes of cabbage and 20 S-haplotypes of broccoli was determined by a pollination test. In order to identify the S-alleles, we performed PCR-RFLP with a mixture of the primers that are related to the S-locus glycoprotein (SLG) gene, which corresponds to the results of the pollination test. The selected primers amplified all of the single bands of about 1,150 bp in all 40 lines of cabbage and broccoli. Three out of 20 lines of cabbage were amplified by class I SLG specific primers, whereas all of the lines of the cabbage were amplified by class II SLG specific primers. Therefore, we could not classify class I and class II precisely by the class I and class II primers. However, 15 out of 20 lines of broccoli were amplified by the class I SLG specific primers. The remaining 5 lines were amplified with the class II SLG specific primers. We then digested the amplified PCR products with various restriction endonucleases and chose a restriction endonuclease, which accords exactly with the results of the diallel cross. The best one was HinfI. Its RFLP result was the same as that of the nucleotide sequence analysis. The 40 lines of cabbage and broccoli consisted of 16 different S-haplotypes. Therefore, the PCR-RFLP analysis was quicker and more precise in identifying the characteristics of S-haplotypes that are used in breeding. Also, we were able to check whether the lines could be mixed. The S-genotypes were difficult to determine due to the different flowering time.

Alleles↗
PubMed2001

Interspecific hybridization in Brassica juncea and Brassica tournefortii through embryo rescue and their evaluation for biotic and abiotic stress tolerance.

Interspecific hybrids were obtained in an otherwise incompatible cross Brassica juncea x Brassica tournefortii through in vitro culture of hybrid embryos. The best response was observed from culture of embryos excised 20 days after pollination on MS medium supplemented with kinetin, alpha-naphthylacetic acid, gibberellic acid, glutamine and casein hydrolysate. One hybrid plant had many distinct or intermediate characters. It was tolerant to aphid attack, exhibited irregularities in meiotic events and was partially fertile. The F2 open pollinated and BC1 progenies showed a large diversity in their morphological traits and some promising plants with less aphid infection, drought tolerance and high yield were selected.

Brassica↗
PubMed2001

Variation in skin reactivity inhalant allergens estimated by the end-point technique.

Skin prick testing is commonly used to diagnose IgE-mediated sensitization to allergens, whereas the longitudinal variability in positive/negative results can be used for clinical and epidemiological purposes. Few publications have investigated the longitudinal variability in skin reactivity, and most studies have concluded that seasonal changes in exposure to environmental allergens are paralleled by a change in skin reactivity. Our trial investigated the relationship between variations in skin reactivity and seasonal exposure to allergens in sensitized subjects, by use of a sensitive method-the end-point technique. Forty-three patients monosensitized to inhalant allergens were selected, and the skin prick end-point technique with serial 1:4 dilutions of standardized commercial allergens was used to assess skin reactivity. Twenty-two patients sensitized to pollens with a short pollination period were tested before and after the pollen season, whereas the other 21 patients sensitized to house dust mites or to a species with a long pollination period such as Parietaria were tested in the same month 12 months later. Patients tested with the end-point technique showed a large interindividual variability in skin reactivity. None of the patients in either group showed a decrease in skin sensitivity with time whereas 9 out of 43 showed no change and 34 out of 43 showed an increase (p < .0001). According to our data, skin reactivity increases in sensitized subjects over time, and this increase seems not to have a circannual rhythm related to the seasonal exposure to environmental allergens, since it can be detected both in pollen- and mite-sensitized patients after a 12-month interval.

Administration, Inhalation↗
PubMed2002

[Instability of the ploidy level in autotetraploid sorghum plants from a line with variable male fertility].

It was found that, in some of the plants in generations C1-C5 of induced tetraploids in the semisterile sorghum line AS-1-30, more than 30% of pollen grains (PGs) have sizes typical of haploid PGs. Pollen of these plants was used to pollinate different lines of sorghum with cytoplasmic male sterility (CMS). Diploid hybrids were obtained, which confirms the presence of haploid PGs in the tetraploids studied. When tetraploid plants with an increased frequency of haploid PGs were pollinated with pollen of plants from fertile diploid lines, diploid hybrids were also obtained. This demonstrates that the tetraploids studied had haploid ovicells. In generation C4, a chimeric plant was found; one of its shoots was diploid (judging from morphological characters) and produced as many as 99% of haploid PGs. It is assumed that haploid gametes in autotetraploids are formed through somatic reduction of chromosomes at different ontogenetic stages.

Edible Grain↗
PubMed2002

[Temporal and geographic development of the main allergenic pollens in France: 1987-2001].

At various occasions, we presented the temporal and geographical evolution of pollination during ten to fifteen last years on various sites of the French network. The year 2000 had shown often different characteristics for some tax for part of the towns of France. An hypothesis had been suggested blaming the great storm at the end of December 1999. Work presented has pure goal to prolong of one year (2001) the curves of evolution of all taxa and those of main allergenic pollens so, the share to consolidate or not the assumption 2000 and the another share, to present the assessment of pollination during the season 2001.

Biological Evolution↗
PubMed2002

[Study of the coverage of pollen capture in Lyon over three seasons (1999, 2000, 2001)].

For the third consecutive year, the two sensors of the type HIRST of the National Network of aerobiology monitoring (RNSA) worked on the agglomeration of Lyon. The primary trap (Lyon 1) is located at 26 m height on a roof in southern zone of Lyon (district of Gerland), the second (Lyon 2) is located in northern zone of the city (district of Vaise) on a roof at 15 m height compared to the ground. The study of the daily variations of the pollinic counts over the first two years had shown a perfect parallelism for pollens of trees, Poaceae and Urticaceae. Only the curves of pollens of ambrosia presented different layouts between the two pollen traps. The study of this third year makes it possible to consolidate the proceeding results and to appreciate the value of the cover of a Hirst pollen trap in urban implantation within the framework of the allergo-pollinic monitoring.

Environmental Monitoring↗
PubMed2002

[Using RAPD for estimating genetic polymorphism in and phylogenetic relationships among species of the genus Lycopersicon (Tourn.) Mill].

RAPD genome analysis of 53 species and cultivars of the genus Lycopersicon (Tourn.) Mill. revealed their high genetic polymorphism (Tourn.) Mill., based on which their phylogenetic relationships were inferred. In total, 248 polymorphic DNA fragments were amplified. Intraspecific polymorphism was maximum (79%) in L. peruvianum and minimum (9%) in L. parviflorum. In general, genome divergence among cross-pollinating tomato species was substantially higher than in self-pollinating species. An UPGMA dendrogram constructed from the RAPD patterns was consisted with the Lycopersicon phylogeny inferred from the molecular data of RFLP, ISSR, and microsatellite analyses and with a classification based on morphological characters. The relationships of taxa within the genus Lycopersicon are discussed.

Phylogeny↗
PubMed2002

Molecular characterization of a GA-inducible gene, Cvsus1, in developing watermelon seeds.

To understand the molecular mechanisms that control seed development, we isolated a seed-preferential gene from ESTs of developing watermelon seeds. The gene Cvsus1 encodes a protein that is 86% identical to the Vicia faba sucrose synthase expressed in developing seeds. RNA blot analysis showed that Cvsus1 was preferentially expressed in watermelon seeds. We also investigated gene expression levels both in pollinated seeds and in parthenocarpic seeds, which lack zygotic tissues. Whereas the transcript level of Cvsus1 was rapidly increased during normal seed development, the expression was not significantly increased in the parthenocarpic seeds. However, treating the parthenocarpic fruits with GA3 strongly induced Cvsus1 expression, up to the level accumulated in pollinated seeds. These results suggest that Cvsus1 is induced in maternal tissues via signals from the zygotic tissues, and that GA may be one of those signals.

Blotting, Southern↗
PubMed2002

[Bronchial reactivity in patients with seasonal allergic rhinitis].

The allergic rhinitis (AR) is an important risk factor for the development of asthma. In significant number of patients with AR, the non-specific bronchial hyperresponsiveness (BHR) could be demonstrated. It has been anticipated that these patients were at the greater risk for asthma. This study was aimed to determine the frequency and intensity of BHR in patients with seasonal AR (SAR) due to Wall pellitory allergy. The patients who were sensitized solely to Parietaria officinalis (Wall pellitory) pollen allergen were recruited in the study, namely patients with SAR (n = 26), SAR with seasonal asthma (n = 23) as well as healthy volunteers (n = 10). In all subjects the clinical check-up, spirometry and bronchial challenge test with metacholine were performed before, during the peak, and after the peak of pollination of pellitory. Comparing to initial findings (23%), in patients with SAR the prevalence of BHR significantly increased during the peak of pollination (50%, p = 0.0039), and remained increased thereafter (43%, p = 0.0319). In patients with SAR and asthma prevalence and intensity of BHR was even higher with the similar seasonal variations. Comparing to initial findings (83%), the prevalence of BHR significantly increased during the peak of season (100%, p = 0.0001), and remained increased thereafter (87%, p = 0.061). In both groups of patients the intensity of BHR (median PC20) increased as well: 4.8, 2.05, and 2.45 mg/mL in patients with SAR, and 0.35, 0.16, and 0.20 mg/mL in patients with SAR and asthma. In healthy volunteers no significant BHR was observed. The results of the present study confirm significant prevalence of BHR in patients with SAR due to pellitory allergy. It is important to determine BHR in patients with SAR and without asthma because the appropriate pharmacotherapeutic and preventive measures (anti-inflammatory medication and specific immunotherapy) could prevent the development of asthma in these patients.

Adult↗
PubMed2003

[The effect of genotypes of parental rye lines on the development of quantitative traits in primary octoploid Triticale: spike fertility].

The number of seeds and seed setting in the main spike were studied in primary octoploid triticale obtained from crosses between the common wheat cultivar Chinese Spring and 66 inbred rye lines. In some rye lines, the mutations of self-fertility were identified in the S, Z, or T incompatibility loci. The number of seeds was determined under controlled self-pollination of the main spike. In the set of triticale examined, each trait exhibited high variation. Hence, the rye lines were suggested to carry gene alleles both increasing and decreasing these traits in triticale. All the traits studied were significantly influenced by environmental conditions. Ten triticale lines were identified, which had the largest seed setting under self-pollination. Seven out of ten samples with the high number of seeds carried mutations in the T locus and in the three samples, the unidentified self-fertility mutations were present. The triticale lines with mutations in the S and Z loci displayed much lower self-fertility on average. The ways and means of identifying and mapping the rye gene responsible for distinctions between the triticale quantitative traits are discussed.

Crosses, Genetic↗
PubMedDate not supplied

Pollen from Glycine species survive cryogenic exposure.

Pollen of 12 genotypes of the annual soybean and its wild perennial relatives were stored without pre-desiccation at low temperatures (-20 C and -196 C) and tested for their viability in vitro. The influence of cryopreserved pollen on pod set and seed production was also investigated. Cryopreserved pollen of all the genotypes showed germination in vitro. Pollen of annual soybean stored at -20 C retained their viability for 4 months, however, pollen of its wild perennial relatives at same storage conditions failed to germinate in vitro. Flowers pollinated with cryopreserved pollen had similar pod set and number of seeds/pod as those pollinated with fresh pollen. Results of this study suggest that cryopreservation of pollen can be used successfully for soybean breeding, and also offers the possibility of conserving the haploid gene pool of soybean and wild perennial species in a cryobank facility.

Adaptation, Physiological↗
PubMed2003

[RAPD-based analysis of introgression of barley genetic material into the genome of alloplasmic wheat lines (Hordeum geniculatum All./ Triticum aestivum L.)].

Genomes of three alloplasmic wheat lines obtained on the basis of barley--wheat hybrid Horderum geniculatum All. (2n = 28) x Triticum aestivum L. (2n = 42)(Pyrotrix 28) were examined using random amplified polymorphic DNA (RAPD) analysis. Line L-29 was obtained after first backcross of the initial hybrid with the wheat variety Pyrotrix 28 and ten subsequent self-pollinating generations. This line was represented by euploid plants with typical to the common wheat chromosome number (2n = 42), as well as by aneuploids, which contained an additional telocentric chromosome in the main karyotype (2n = 42 + t). Lines L-26 and L-27 were obtained by two backcrosses of one BC1 plant with the wheat variety Novosibirskaya 67 and one subsequent self-polination of one BC3 plant. Chromosome number in all these plants corresponded to 2n = 40 + 4t. RAPD analysis was carried out using seven primers, which were previously proved to be effective for identification of the barley genome fragments within hybrid genomes of alloplasmic lines. The presence of barley genome fragments in line L-29 was revealed by use of five primers, while in lines L-26 and L-27 these fragments were detected by use of one primer. The significant difference in the number of barley RAPD fragments in the genomes of alloplasmic lines obtained at different backcrossing stages suggests more intense displacement of barley genome during backcrossing compared to self-pollination in BC1 plants.

Chimera↗