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本研究的目的是发现并解释由于照射种子而引起染色体畸变的不同类型以及估价不同照射量引起的异常细胞频率,由此确立二倍体(2n=14)和四倍体(2n=28)(秋水仙诱导)黄麻之间的相对辐射敏感性。用~(60)Coγ射线60、70和80千伦处理两个不同倍数水平的风干种子,并对处理和对照的根尖有丝分裂的不同时期进行研究。两个类型未经处理的根尖细胞都没有染色体畸变。照射样品的畸变包括:(1)只有染色质桥,(2)只有落后染色体,(3)在两种类型根尖细胞的分裂后期既有染色质桥又有落后染色体,(4)四倍体黄麻中期染色体的长度变异很大。根据其它工作者在这个领域的发现,对引起畸变的可能原因进行了讨论。在两个倍数水平上随着照射量的提高,异常细胞频率也均有提高。但在一定的照射量下,四倍体黄麻产生的异常染色体比二倍体的更多。结论认为人工引变的同源四倍体辐射敏感性比二倍体类型更为敏感。这大概是由于同源四倍体起源于人工的性质及其缺乏充分的适应性以保护自己免遭辐射作用。
The purpose of this study was to identify and explain the different types of chromosomal aberrations caused by seed irradiation and to estimate abnormal cell frequencies caused by different exposures, thus establishing diploid (2n = 14) and tetraploid (2n = 28) ( Daffodil induced) relative radiation sensitivity between jute. Air-dried seeds at two different fold levels were treated with ~ (60) Coγ-rays at 60, 70 and 80 kilo-oerson, and different periods of mitral apical mitosis were investigated and compared. Both types of untreated root tip cells have no chromosomal aberrations. The aberrations of the irradiated sample include: (1) only the chromatin bridge, (2) only the backward chromosome, (3) both the chromatin bridge and the trailing chromosome at the late division of both types of root tip cells, (4) the tetraploid Jute metaphase chromosome length variation. Based on the findings of other workers in this field, possible causes of distortion are discussed. Abnormal cell frequency also increased with the increase of irradiation dose at two multiple levels. However, tetraploid jute produced more abnormal chromosomes than diploids at a certain irradiation dose. The conclusion is that artificial autotetraploid radiation sensitivity is more sensitive than diploid type. This is presumably due to the artificial nature of autotetraploid and its lack of adequate adaptability to protect itself from radiation.