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Pollen Mother Cells (pollen + mother_cell)
Selected AbstractsIntrogression of a gene for delayed pigment gland morphogenesis from Gossypium bickii into upland cottonPLANT BREEDING, Issue 6 2005S. J. Zhu Abstract The presence of gossypol and its derivatives above the WHO/FAO standards (0.02,0.04%) in cotton seed oil and meal limits its usage as food and feed. To the contrary, the presence of pigment glands filled with gossypol and its derivatives helps to protect cotton plants from phytophageous pests. Thus a desirable cultivar would have glandless seeds on a glanded plant. This paper describes results on the successful introgression of this trait from Gossypium bickii into cultivated upland cotton. Five different tri-specific hybrids (ABH1, ABH2, ABH3, ABH4 and ABH5) were obtained by crossing the amphidiploid F1 (G. arboreum × G. bickii) with different gland genotypes of G. hirsutum as male parent. The hybrids were highly sterile, and their chromosome configuration at meiosis metaphase 1 (M1) in pollen mother cell (PMC) was 2n = 52 = 41.04 I + 4.54 II + 0.57 III + 0.04 IV. All five hybrids were similar in morphological characters, except for the gland expression and gossypol contents. The hybrid (ABH3) derived from genotype Gl2Gl2gl3gl3 of upland cotton (a single gene dominant line) had completely introgressed the target trait of G. bickii. While ABH1 and ABH2, which derived from recessive (gl2gl2gl3gl3) or dominant (GlGl) glandless upland cotton genotypes, had glandless seeds too, but the density and size of the glands on the plant were reduced significantly. [source] Microsporogenesis and meiotic behavior in nine species of the genus PinusJOURNAL OF SYSTEMATICS EVOLUTION, Issue 4 2009Hui-Sheng DENG Abstract The meiotic behavior of 10 taxa (nine species and one variety) of the genus Pinus was investigated using pollen mother cells (PMCs) to reveal the differentiation among karyotypes. Chromosome spreads were prepared by conventional squashing. The meiotic index and the average configuration were higher, whereas the frequency of aberrance (chromosomal bridges, fragments, or micronuclei) was lower, in all 10 taxa compared with other gymnosperms. The meiotic index, average configuration, and frequency of irregularity were found to be uniform among the species. It was shown that the genomes of the Pinus species investigated were highly stable, confirming results of previous mitotic analyses in this genus. However, slight differentiation of homologous chromosomes among genomes was revealed by analysis of meiotic configurations in Pinus nigra var. poiretiana. Quadrivalents were observed in 9.31% of PMCs in this species. This is the first time that quadrivalents have been observed in gymnosperms. [source] Expression of CP4 EPSPS in microspores and tapetum cells of cotton (Gossypium hirsutum) is critical for male reproductive development in response to late-stage glyphosate applicationsPLANT BIOTECHNOLOGY JOURNAL, Issue 5 2006Yun-Chia Sophia Chen Summary Plants expressing Agrobacterium sp. strain CP4 5-enolpyruvylshikimate-3-phosphate synthase (CP4 EPSPS) are known to be resistant to glyphosate, a potent herbicide that inhibits the activity of the endogenous plant EPSPS. The RR1445 transgenic cotton line (current commercial line for Roundup Ready® Cotton) was generated using the figwort mosaic virus (FMV) 35S promoter to drive the expression of the CP4 EPSPS gene, and has excellent vegetative tolerance to glyphosate. However, with high glyphosate application rates at developmental stages later than the four-leaf stage (late-stage applications: applications that are inconsistent with the Roundup® labels), RR1445 shows male sterility. Another transgenic cotton line, RR60, was generated using the FMV 35S promoter and the Arabidopsis elongation factor-1, promoter (AtEF1,) for the expression of CP4 EPSPS. RR60 has excellent vegetative and reproductive tolerance to applications of glyphosate at all developmental stages. Histochemical analyses were conducted to examine the male reproductive development at the cellular level of these cotton lines in response to glyphosate applications, and to investigate the correlation between glyphosate injury and the expression of CP4 EPSPS in male reproductive tissues. The expression of CP4 EPSPS in RR60 was found to be strong in all male reproductive cell types. Conversely, CP4 EPSPS expression in RR1445 was low in pollen mother cells, male gametophytes and tapetum, three crucial male reproductive cell types. Our results indicate that the FMV 35S promoter, although expressing strongly in most vegetative tissues in plants, has extremely low activity in these cell types. [source] Production and characterization of an amphiploid between common wheat and Psathyrostachys huashanica Keng ex KuoPLANT BREEDING, Issue 1 2009H. Y. Kang Abstract Wide crosses and synthetic amphiploids have played an important role in introgressing desirable traits from related species into cultivated wheat. Hybrids between Triticum aestivum cv. ,J-11' and Psathyrostachys huashanica were treated with colchicine, to produce a new intergeneric amphiploid (PHW-SA). The morphological characteristics of PHW-SA resembled the parent ,J-11'. PHW-SA plants have purple internodes and pubescence in the basal spikelet, inherited from the P. huashanica parent. Somatic chromosome numbers varied from 2n = 51 to 2n = 56, with 70.59% of plants having 56 chromosomes. At metaphase I, PHW-SA (2n = 56) plants showed an average of 1.15 univalents, 27.34 bivalents, 0.03 trivalents and 0.02 tetravalents per cell; complete chromosome pairing occurred in 50% of the pollen mother cells. A survey of disease resistances revealed that the stripe rust resistance from P. huashanica was expressed, but powdery mildew resistance was suppressed. The fertility of PHW-SA was 60%. [source] Homoeological relationships between the f chromosome of Brassica rapa and the e chromosome of Brassica oleraceaPLANT BREEDING, Issue 2 2002Y. Kaneko Abstract Eight plants of the putative double monosomic addition line (DMAL, 2n= 20) were developed by crossing a monosomic chromosome addition line of radish [f(A)-type monosomic addition line (MAL) (2n= 19)] carrying the f chromosome of Brassica rapa (2n= 20, AA) with another [e(C)-type MAL (2n= 19)] having the echromosome of Brassica oleracea (2n= 18, CC). The homoeological relationships between the two alien chromosomes were investigated by morphological, cytogenetic and random amplified polymorphic DNA (RAPD) analysis. Seventeen morphological traits that were not present in the radish cv. ,Shogoin' were observed in both MALs and these traits were substantially exhibited in DMAL plants. At the first metaphase of pollen mother cells (PMCs), the two parental MALs showed a chromosome configuration of 9II +1I, demonstrating impossibility of recombination between the R and the added chromosomes. The DMALs formed 10II in approximately 73% of PMCs, with one bivalent showing loose pairing between two chromosomes differing in size. In an attempt to identify the two MALs by RAPD-specific markers using 26 selected random primers, 13 and 20 bands were specific for the f(A)-type and the e(C)-type MALs, respectively; 12 bands were common to both MALs (26.7%). In conclusion, the f chromosome of B. rapa is homoeologous to the e chromosome of B. oleracea. The genetic domain (genes) for 17 morphological traits are linked to each homoeologous chromosome bearing 27% of the corresponding RAPD markers. [source] Effect of the ph1b mutant on chromosome pairing in hybrids between Dasypyrum villosum and Triticum aestivumPLANT BREEDING, Issue 4 2001M. Q. Yu Abstract Chromosome pairing was analysed in F1 hybrids of the wheat cultivar ,Chinese Spring' (CS) and its ph1b mutant (CSphlb) with Dasypyrum villosum. On average, 1.61 chromosomes per cell paired in the hybrid CS ×D. villosum, but 14.43 in the hybrid CS ph1b×D. villosum. Genomic fluorescence in situ hybridization (GISH) revealed three types of homoeologous association between wheat (W) and D. villosum (D) chromosomes (W-D, D-W-W and D-W-D) in pollen mother cells of the CS ph1b×D. villosum hybrid, and only one type (W-W), in the CS ×D. villosum hybrid. Both F1 hybrids were self-sterile. The seed set of the backcross of CS ×D. villosum with CS was 6.67% and that of CS ph1b×D. villosum with CS or CS ph1b was only 0.45%. The chromosome number of BC1 plants varied from 48 to 72. Translocations of chromosome segments or entire arms between wheat and D. villosum chromosomes were detected by GISH in the BC1 plants from the backcross of CS ph1b×D. villosum to CS ph1b. [source] | ||||||||||