摘要
通过“供体──受体”原生质体融合获得５个“波缘烟草＋普通烟草”体细胞杂种细胞系（ＴＵ＿１至ＴＵ＿５）。对５个杂种细胞系的细胞学观察表明，其中２个系为多细胞融合产物，其平均染色体数目分别为１６７．２和１９８．４；３个系为二细胞融合产物，其平均染色体数目分别为５４．３７０．６和６２．８。杂种细胞系的一个明显特征是所有观察的中期细胞均存在数量不等的畸变染色体。对５个杂种细胞系再生植株叶片苹果酸脱氢酶和酯酶的同工酶分析结果表明，它们均为程度不同的不对称核杂种，即只含有供体亲本（波缘烟草）的部分核基因组。以小麦ｒＤＮＡ为探针对杂种细胞系基因组ＤＮＡ的Ｓｏｕｔｈｅｒｎ杂交结果表明，杂种中双亲的载有ｒＤＮＡ的染色体可能均有部分消除；此外，杂种中新ＤＮＡ片段的存在说明双亲ｒＤＮＡ可能发生了分子间重组。两个由多细胞融合产生的杂种细胞系（ＴＵ＿２和ＴＵ＿５）再生苗不易生根而且形态上异常。３个由二细胞融合产生的杂种细胞系（ＴＵ＿１、ＴＵ＿３和ＴＵ＿４）再生苗可生根长大，形态上类似受体亲本；对其根尖的细胞学观察表明，染色体数目在５１─６６之间，说明均为只含有少量供体亲本染色体的不对称核杂种。
Mesophyll protoplasts of Nicotiana tabacum and callus protoplasts of N. undulata were chemically fused by the'donor-recipient'fusion system(irradiating the donor parental protoplasts with high dose X or γ rays prior to fusion with protoplast of recipient parent).Cytological observation on 5 hybrid cell lines revealed that 2 of them were probably multi-cell fusion products with mean chromosome numbers 167.2 and 198.4 respectively.While the other 3 cell lines were binary fusion products with mean chromosome numbers 54.3,70.6 and 62.8 respectively.A characteristic of these 5 hybrid cell lines was the uniquity of chromosome aberrations in all the metaphase cells examined,although the amount of aberrant chromosomes varied greatly among the cell lines. MDH and esterase isozyme analysis of leaf material from regenerants of the 5 hybrid cell lines showed that they were all asymmetric nuclear hybrids with only partial genome from the donor parent N. undulata.Ribosomal DNA analysis indicated that at least some chromosmoes(such as satelite chromosome)of the recipient parent might also be eliminated. The existance of an unique fragment in 2 of the 4 hybrids suggested that intermolecular rDNA recombination between the two parents had occured. Morphology of regenerants from the 2 multi-cell fusion products were abnormal and with difficulty to regenerate roots.While plants regenerated from the other 3 hybrid cell lines were morphologically similar to the recipient parent N.tabacum and have been transferred to soil. Cytological observation on root-tip cells from these plants showed that they had chromosome numbers from 51 to 66, indicating the high asymmetric nature of these nuclear somatic hybrids.
基金
国家教委重点跟踪年轻教师项目
关键词
烟草
种间杂交
体细胞杂交
Nicotiana tabacum L.,N. undulata L.,Protoplast fusion,Partial genome transfer
