Han Rong, Wang Xun-Ling, Yue Ming, Qi Zhi
College of Life Sciences, Northwest University, Xi'an 710069, China.
Yi Chuan Xue Bao. 2002 Jun;29(6):537-41.
The chromosomal mutation and mitosis of the wheat (Triticum aestivum, cv. 93-4736) were observed under the condition of the enhanced ultraviolet-B radiation. The results showed that the number of cells in mitosis of the UV-B treatments was 68.09% of the control, indicating that the UV-B treatment significantly inhibited division of root tip cells in wheat. Using t-test at P < or = 0.05, there was a significant difference between the control and the treatments. The enhanced UV-B significantly increased aberration frequency of chromosomes and cells (t = 9.51, n = 3, P < 0.05). Several types of chromosomal aberration such as lagging chromosomes of chromosomes bridge, fragments, nuclear aberration occurred in both of control and UV-B treatment. However, the frequency of lagging chromosome and fragments of chromosome was increased significantly by enhanced UV-B radiation (P < 0.05). Furthermore, the UV-B treatment caused several new types of chromosomal aberrations, such as three-bundle, four-bundle and six-bundle. In our opinion, these new types of chromosomal aberrations should be called 'partition-bundle division'. Under the condition of UV-B treatment, the amount of aberrations only accounted for 2.84% of the total during the interphase. In the period, nuclear abnormality appeared mainly in forms of micronucleolus and polycaryon. In the metaphase, there mainly exist fragment chromosome, which accounted for 26.67% of the total aberrations, being secondary to lagging chromosomes. The amount of chromosomal abnormality in the anaphase and telophase was the biggest, which included the types of bridge, lagging chromosomes, etc. Among the types, the lagging chromosomes were dominant, accounting for 32.84% of the total. In this study, what was especially emphasized was the UV-B induced abnormal mitosis that was first found. In the anaphase and telophase of the treated cells, chromosomes were divided into 3 bundles, 4 bundles, or 6 bundles, respectively accounting for 8.77%, 15.43%, and 8.02% of the total abnormal cells. Three-bundle division was nonsymmetrical. The number of chromosomes in each of the three bundles was not completely equal. Four-bundle division mainly symmetrized at direction of axis, the number of each of the two bundles on the same axis was basically the same, but was different from that on another axis. Four-bundle division was conducted in two patterns of division. With respect to the much more special six-bundle division, chromosomes were regularly divided into 3 groups, symmetrizing each other. As viewed from the number of chromosomes in each bundle, it was smaller than that in normal somatic cells. In the abnormal division of cells, cell plate or cell wall between the two divided bundles was not found, leading to 'multi-bundle bodies' occurrence by the end of cell division. Therefore, the abnormal division of the somatic cells should be called 'the multi-bundle division' or 'the partition bundle division'.
在增强紫外线B辐射条件下，对小麦（普通小麦，品种93 - 4736）的染色体突变和有丝分裂进行了观察。结果表明，紫外线B处理组有丝分裂的细胞数量为对照组的68.09%，这表明紫外线B处理显著抑制了小麦根尖细胞的分裂。采用P≤0.05的t检验，对照组与处理组之间存在显著差异。增强的紫外线B显著增加了染色体和细胞的畸变频率（t = 9.51，n = 3，P < 0.05）。在对照组和紫外线B处理组中均出现了几种类型的染色体畸变，如染色体桥、片段、核畸变等滞后染色体。然而，增强的紫外线B辐射显著增加了滞后染色体和染色体片段的频率（P < 0.05）。此外，紫外线B处理还导致了几种新的染色体畸变类型，如三束、四束和六束。我们认为，这些新的染色体畸变类型应称为“分区束分裂”。在紫外线B处理条件下，间期畸变数量仅占总数的2.84%。在此期间，核异常主要表现为微核仁和多核体形式。在中期，主要存在片段染色体，占总畸变的26.67%，仅次于滞后染色体。后期和末期的染色体异常数量最多，包括桥、滞后染色体等类型。在这些类型中，滞后染色体占主导，占总数的32.84%。在本研究中，特别强调的是首次发现的紫外线B诱导的异常有丝分裂。在处理细胞的后期和末期，染色体分别分为3束、4束或6束，分别占总异常细胞的8.77%、15.43%和8.02%。三束分裂不对称。三束中每束的染色体数量不完全相等。四束分裂主要在轴向上对称，同一轴上的两束中每束的数量基本相同，但与另一轴上的不同。四束分裂以两种分裂模式进行。对于更为特殊的六束分裂，染色体规则地分为3组，相互对称。从每束中的染色体数量来看，它比正常体细胞中的要少。在细胞的异常分裂中，未发现两个分开的束之间的细胞板或细胞壁，导致细胞分裂结束时出现“多束体”。因此，体细胞的异常分裂应称为“多束分裂”或“分区束分裂”。
