The assembly of the microtubule-based spindle structure in plant meiosis remains poorly understood compared with our knowledge of mitotic spindle formation. One of the approaches in our understanding of microtubule dynamics is to study spindle assembly in meiosis of amphyhaploids. Using immunostaining with phH3Ser10, CENH3 and α-tubulin-specific antibodies, we studied the chromosome distribution and spindle organisation in meiosis of F1 2R(2D)xR wheat-rye hybrids (genome structure ABDR, 4× = 28), as well as in wheat and rye mitosis and meiosis. At the prometaphase of mitosis, spindle assembly was asymmetric; one half of the spindle assembled before the other, with simultaneous chromosome alignment in the spindle mid-zone. At diakinesis in wheat and rye, microtubules formed a pro-spindle which was subsequently disassembled followed by a bipolar spindle assembly. In the first meiosis of hybrids 2R(2D)xR, a bipolar spindle was not found and the kinetochore microtubules distributed the chromosomes. Univalent chromosomes are characterised by a monopolar orientation and maintenance of sister chromatid and centromere cohesion. Presence of bivalents did not affect the formation of a bipolar spindle. Since the central spindle was absent, phragmoplast originates from “interpolar” microtubules generated by kinetochores. Cell plate development occurred with a delay. However, meiocytes in meiosis II contained apparently normal bipolar spindles. Thus, we can conclude that: (1) cohesion maintenance in centromeres and between arms of sister chromatids may negatively affect bipolar spindle formation in the first meiosis; (2) 2R/2D rye/wheat chromosome substitution affects the regulation of the random chromosome distribution in the absence of a bipolar spindle.

中文翻译：

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F1二体代换系2R（2D）x黑麦杂种（ABDR，4×= 28）的第一个减数分裂的随机染色体分布

与我们对有丝分裂纺锤体形成的了解相比，在植物减数分裂中基于微管的纺锤体结构的组装仍然知之甚少。在我们对微管动力学的理解中，方法之一是研究两亲单倍体减数分裂中的纺锤体组装。使用phH3Ser10，CENH3和α-微管蛋白特异性抗体进行免疫染色，我们研究了F1 2R（2D）xR小麦-黑麦杂种（基因组结构ABDR，4×= 28）的减数分裂中的染色体分布和纺锤体组织。小麦和黑麦的有丝分裂和减数分裂。在有丝分裂的前期，纺锤体的组装是不对称的。纺锤的一半先于另一半组装，同时染色体在纺锤中部对齐。在小麦和黑麦的动态诊断中，微管形成了一个前主轴，随后将其拆卸，随后是一个双极主轴组件。在杂种2R（2D）xR的第一个减数分裂中，未发现双极纺锤体，并且动粒微管分布了染色体。单价染色体的特征是单极性取向，并保持姐妹染色单体和着丝粒的内聚力。二价原子的存在不影响双极纺锤体的形成。由于不存在中心纺锤体，因此原生质膜起源于动植物产生的“极间”微管。细胞板发育发生延迟。但是，减数分裂II中的减数分裂细胞显然包含正常的双极纺锤体。因此，我们可以得出以下结论：（1）着丝粒和姐妹染色单体两臂之间的内聚力维持可能对第一个减数分裂的双极纺锤体形成产生负面影响；（2）在没有双极纺锤体的情况下，2R / 2D黑麦/小麦染色体替代会影响随机染色体分布的调节。