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1.
利用整体压片法 ,对分别隶属于球角科和长角科的两种跳虫似微小球角 (Hypogastruraadex ilis (Stach ,196 4 ) )和曲毛裸长 (SinellacurvisetaBrook 1889)的染色体进行了首次观察。发现似微小球角单倍染色体数目n =7,雄性有 13条染色体 ,雌性有 14条 ,为XO型性别决定 ;曲毛裸长n =6 ,雄性 2n =11,雌性 2n =12 ,同样为XO型性别决定。还记述了雄性似微小球角的减数分裂过程 :在分裂前期 ,同源染色体进行配对 ;部分同源染色体发生交叉 ,部分仅末端相连 ;早后期Ⅰ ,当常染色体向两极移动时 ,性染色体仍滞后于赤道板中央。 相似文献
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普通小麦与冰草间杂种的细胞遗传学及其自交可育性 总被引:10,自引:2,他引:10
为了进一步研究冰草属(Agropyron Gaertn.)的P染色体组与小麦染色体组间的遗传关系和评价P染色体组在属间杂种自交可育性上的遗传效应,获得了普通小麦品种Fukuho(Triticum aestivum cv.Fukuho,2n=42;AABBDD)与3个不同来源的四倍体冰草(A.cristatum<L.>Gaertn.,2n=28;PPPP)间的杂种(2n=35;ABDPP)。结果表明 相似文献
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卵巢发育阻滞的人工三倍体鱼减数分裂染色体配对的光镜观察 总被引:4,自引:0,他引:4
采用界面铺张制片和硝酸银一步染色的方法,对人工三倍体水晶彩鲫卵巢发育阻滞型个体的减数分裂染色体配对进行了光镜观察。在分化有初级卵母细胞的卵巢发育阻滞型的三倍体鱼中,减数分裂粗线期细胞主要的由二价体和单价体组成,也见有少量三价体和其它多价体,其染色体成员数大多在90左右;在不同细胞间,染色体的大小变化较大;配对联会过程中形成的配对叉和产生的特异蛋白在一些细胞中明显可见。文中讨论了三倍体染色体配对紊乱 相似文献
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小冰麦异附加系中天兰冰草染色体的变异 总被引:2,自引:1,他引:2
通过对两套14种小冰麦异附加系的体细胞染色体观察,发现3个异附加系各有1对染色体发生了显著变异。其中TAl-14t有1对端着丝点染色体,TAl-22s和TAl-27s各有1对近中着丝点的小染色体。通过组胞遗传学分析,从3个方面证明了发生变异的染色体均来自天兰冰草。此外还发现在其中的两个异附加系(TAI-14t和TAl-27s)中可能产生了自发易位。 相似文献
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T. E. Miller S. M. Reader K. A. Purdie I. P. King 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1994,89(2-3):255-258
Genomic in-situ hybridization (GISH) was used to determine the amount of wheat-rye chromosome pairing in wheat (Triticum aestivum) x rye (Secale cereale) hybrids having chromosome 5B present, absent, or replaced by an extra dose of chromosome 5D. The levels of overall chromosome pairing were similar to those reported earlier but the levels of wheat-rye pairing were higher than earlier determinations using C-banding. Significant differences in chromosome pairing were found between the three genotypes studied. Both of the chromosome-5B-deficient hybrid genotypes showed much higher pairing than the euploid wheat hybrid. However, the 5B-deficient hybrid carrying an extra chromosome 5D had significantly less wheat-rye pairing than the simple 5B-deficient genotype, indicating the presence of a suppressing factor on chromosome 5D. Non-homologous/non-homoeologous chromosome pairing was observed in all three hybrid genotypes. The value of GISH for assessing the level of wheat-alien chromosome pairing in wheat/alien hybrids and the effectiveness of wheat genotypes that affect homoeologous chromosome pairing is demonstrated. 相似文献
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Meiosis is the specialized eukaryotic cell division that permits the halving of ploidy necessary for game- togenesis in sexually reproducing organisms, This involves a single round of DNA replication followed by two successive divisions. To ensure balanced segregation, homologous chromosome pairs must migrate to opposite poles at the first meiotic division and this means that they must recognize and pair with each other beforehand. Although understanding of the mechanisms by which meiotic chromosomes find and pair with their homologs has greatly advanced, it remains far from being fully understood. With some notable exceptions such as male Drosophila, the recognition and physical link- age of homologs at the first meiotic division involves homologous recombination. However, in addition to this, it is clear that many organisms, including plants, have also evolved a series of recombination-independent mechanisms to facili- tate homolog recognition and pairing. These implicate chromosome structure and dynamics, telomeres, centromeres, and, most recently, small RNAs. With a particular focus on plants, we present here an overview of understanding of these early, recombination-independent events that act in the pairing of homologous chromosomes during the first meiotic division, 相似文献
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Tian Xian-hua Xiao Ya-ping Liu Quan-hong Zhu Bi-cai Wang Zhong-hui Yuan Shi-qu 《植物分类学报:英文版》1994,32(3):240-245
The chromosome numbers in fourteen moss species from the Qinling Range, and karyotype of Mnium lycopodioides are reported in this paper. Immature capsules were used as material. Bryum capillare L. ex Hedw was found. to have n = 10; Mnium lycopodioides Schwaegr. n = 6 with the karyotype formula n = 6 = 3m+3sm (1SAT); Plagiomnium maximoviczii (Lindl.)T. Kop. n=6; Bartramia halleriana var. elongate Turn. n=10+2m; Thuidium delicatulum (Hedw.) Mitt. n= 11; Thuidium philibertii Limpr. n= 10+m; Hygrohypnum ochraceum (Wils.) Loesk. n=10; Drepanocladus uncinatus (Hedw.) Warnst. n = 7+3m; Campylium chrysophyllus (Brid.) J. Lange. n = 10; Brachythecium starkei (Brid.) B. S. G. n=6; Brachythecium buchananii (Hook.) Jaeg. n=6; Brotherella yokohamae (Broth.)Broth. n= 9+2m; Gollamia neckerella (C. MÜll. )Broth. N=7; Pogonatum fastigiatum Mitt. n = 7. No report on the chromosome number of Brotherella yokohamae and Gollania neckerella has been found. The chromosome numbers in Brachythecium starkei andBrachythecium buchananii (Hook.) Jaeg. are different from previous reports, while the others are in accordance with the previous reports. 相似文献
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L. H. Li Y. S. Dong 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1991,81(3):312-316
Summary Intergeneric hybrids between Triticum aestivum cv Chinese Spring (2n=6x=42, AABBDD) and Agropyron michnoi Roshev. (2n=4x=28, PPPP) were obtained by embryo culture. Their spike characteristics were similar to those of common wheat but, unlike their parents, they were long-awned. The average meiotic chromosome pairing at MI of F1 hybrids was: 6.39 I +3.75 rodII+8.64 ringII+0.81 III+0.30 IV+0.04 V, the bivalent and multivalent formation of which was much higher than expected from the genomic formulae. It is especially worthwhile to note that the F1 hybrids were self-fertile, self set being 0.15%, and seeds were easily obtained from the backcross of f1 plants with hexaploid and tetraploid wheats; here the seed set was more than 20.0%. The polyploid taxa and the position of A. Michnoi in Agropyron are discussed. 相似文献
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Meiosis is the crucial process by which sexually propagating eukaryotes give rise to haploid gametes from diploid cells. Several key processes, like homologous chromosomes pairing, synapsis, recombination, and segregation, sequentially take place in meiosis. Although these widely conserved events are under both genetic and epigenetic control, the accurate details of molecular mechanisms are continuing to investigate. Rice is a good model organism for exploring the molecular mechanisms of meiosis in higher plants. So far, 28 rice meiotic genes have been characterized. In this review, we give an overview of the discovery of rice meiotic genes in the last ten years, with a particular focus on their functions in meiosis. 相似文献
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濒危植物矮沙冬青减数分裂期染色体行为的观察 总被引:8,自引:1,他引:8
用涂片法和酶解法,观察了濒危植物矮沙冬青的减数分裂过程。在减数分裂双线期末或终变期初,可以观察到9个二价体,在中期Ⅰ末至后期Ⅰ初,同源染色体基本排列在赤道板上,然后在纺锤丝的牵引下二价体的两条同源染色体分开,分别移向两极,每一极有9条染色体,从而确认该属植物的染色体基数为x=9。在矮沙冬青减数分裂过程中,没有发现染色体有异常行为,认为其小孢子形成过程正常。因此认为矮沙冬青濒危不是染色体行为异常和小孢子发育不正常而造成的。 相似文献
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几种冰草属披碱草属牧草种群地上生物量形成规律的研究 总被引:1,自引:0,他引:1
本文从种群生态的层次,研究了在宁夏盐池干草原向荒漠草原过渡地带冰草属、披碱草属6种牧草种群地上生物量的形成规律。结果表明,供试牧草种群高度生长有明显季节性。与其它5种牧草相比,俄罗斯野麦草生长发育早而快,其种群地上生物量及有效营养物量生长季内的变化曲线均呈单峰式,在乳熟期最大值分别为141.3和86.0g/m2。此外,本文还指出了牧草的最佳利用时期,并在牧草生产上提出一些建议。 相似文献
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冰草属(Agropyron Gaertn.)植物遗传多样性取样策略基于醇溶蛋白的研究 总被引:13,自引:0,他引:13
对冰草属(Agropyron Gaertn.)植物的5个种22个居群分8个取样梯度,分别随机取3、6、9、12、15、18、21、24粒种子的混合样进行醇溶蛋白的A-PAGE分析,结果发现:平均Simpson指数依取样量的增加表现增大,以3粒种子0.922表现最低,以21粒0.933表现最高,变异系数(CV%)为0.41.醇溶蛋白谱带数依所提取的混合样的籽粒数目发生显著变化,冰草属内5个种表现趋势相同,22个居群不同取样整体平均以3粒种子提取的醇溶蛋白谱带数18.38为最少,以18粒种子提取的醇溶蛋白谱带28.24为最多,CV%为13.21.取样量达到12粒以上醇溶蛋白谱带差异不明显(P=0.01),图谱表现基本一致.建议在利用生化指纹进行冰草属居群间及种间的遗传多样性研究中,混合取样量最低应保持在12个个体及以上方能代表居群整体,反映居群的整体遗传特性. 相似文献
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Three stages of meiotic homologous chromosome pairing in wheat: cognition, alignment and synapsis 总被引:4,自引:0,他引:4
Trude Schwarzacher 《Sexual plant reproduction》1997,10(6):324-331
Chromosome painting enabled the study of homologous chromosome behaviour prior to and during meiosis. Total genomic DNA from
rye, used as a probe for in situ hybridization, identified the rye chromosome arm in a wheat-rye translocation line (T5AS·5RL)
at meiotic prophase and the preceding interphase. Accurate staging of the development of the meiocytes was attained by parallel
studies of chromatin morphology, nucleolar behaviour and synaptonemal complex formation in electron microscopy thin sections
and silver-stained surface spreads. Three stages of pairing were identified for the large cereal genomes that are organized
in a Rabl configuration: first, cognition occurs during the long interphase before leptotene, bringing the homologous chromosome
domains into close proximity and possibly starting at the centromere; second, homologous chromosome segments align at late
leptotene; and third, zygotene synapsis initiates near the telomere, although it was also observed to occur near the centromere.
A pairing model is proposed for wheat, with a genome size of 17000 Mbp, that shows prallels to and notable differences from
yeast and mammalian models of meiosis.
Received: 25 January 1997 / Revision accepted: 14 July 1997 相似文献
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报道了内蒙古冰草属一新变种——毛稃沙芦草(Agropyron mongolicum Keng var. helinicum L.Q.Zhao et J. Yang)。该变种外稃密被长柔毛,颖光滑无毛不同于沙芦草(A. mongolicum Keng)和毛沙芦草(A. mongolicum Keng var. villosum H.L.Ying)。 相似文献
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哺乳动物卵母细胞减数分裂研究进展 总被引:2,自引:0,他引:2
介绍了国内外哺乳动物卵母细胞减数分裂研究的现状、内容、技术、方法及意义。特别指出了哺乳动物卵母细胞体外成熟及其相关技术在畜牧业生产、医疗卫生事业中的广泛应用前景和重要的实践意义。 相似文献
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采用醋酸洋红压片法对响叶杨(Populus adenopoda)小孢子母细胞减数分裂进程中的染色体行为进行了研究。结果表明:响叶杨小孢子发生发育过程与其雄花芽/花序的外部特征和花药颜色有着密切关系;住其减数分裂进程中染色体行为正常,表明响叶杨同源染色体间表现出了较高的同源性,在中期Ⅱ平行纺锤体的出现与天然花粉中大花粉的存在可能有一定的联系;同时,减数分裂过程中核仁数目存在若动态变化,这种现象叮能与杨属植物占多倍性起源有关。同一花芽的不同部位,减数分裂进程较不同步,这种小同步性是响叶杨适应环境的一种进化表现。 相似文献