水稻杂种细胞核行为和DNA含量与杂种优势的研究

 利用MIPS-1分析仪研究了11个亲本和9个杂种的细胞核行为和DNA含量，同步测定了每个细胞减数分裂前期、中期、后期和末期的光密度值、集分光密度值以及细胞核的大小。所测定亲本和杂种的4401个细胞的计算机分析结果表明：9个杂种的平均集分光密度值显著高于亲本，但光密度值比亲本的低，杂种的细胞核特别是在减数分裂的前期显著增大。因此，在F1杂合状态下，细胞核中DNA含量增加，而DNA密度下降，这可能有利于基因的表达，从而促进杂种优势的表达。

Nuclear Behaviour and DNA Content of Hybrids and Their Parental Lines Related To Heterosis in Rice

To provide an insight into karyological and molecular bases of heterosis, using advanced techniques with MIPS- 1 imaging analytical instrument, nuclear behaviour and DNA content of nine hybrids and eleven of their parental lines have been cytochewically investigated in rice (Oryza sativa L.).Each nucleus has been synchronically determined for its OD,IOD and size indices, and all of the data obtained from 4401 nuclei have been analysed through a computer. The result shows that an average of the IOD value from nine hybrids is remarkably higher compared with that from their parental lines,whereas the OD value of the nuclei is lower than that of their parents. The result also shows that those nucleus size is significantly expanded in the hybrids, especially in the prophase stage of mitosis. From the results, it might be concluded that the increase of DNA content and the decrease of DNA density as well as the expansion of the nuclei have occurred under the condition of F1 heterozygosity, where the strength of gene expression might have been somewhat enhanced. Undoubtedly, these could be important for understanding karyological and molecular bases of rice heterosis.