草棉同源四倍体的诱导与鉴定

Autotetraploid induction and identification of G.herbaceum

[目的]本研究旨在将二倍体草棉加倍成同源四倍体,获得能够结铃并且育性稳定的同源四倍体,这对于棉花的种质创新和下一步远缘杂交遗传育种具有重要意义。[方法]以二倍体草棉(Gossypium herbaceum L.)为材料,采用改良初生分生组织处理法对其进行多倍体诱变,并对获得的草棉突变型进行形态学、细胞遗传学和流式细胞仪倍性鉴定。[结果]形态性状表明:突变型与野生型相比具有较强的生长势,植株矮壮,叶片颜色浓绿,且叶片皱缩、增厚,茎干较野生型粗,统计分析表明突变型与野生型存在显著差异(P<0.05)。流式细胞仪测定结果显示:突变型的峰值位于400,而野生型峰值位于200,表明突变型DNA含量为野生型的二倍。细胞学结果表明:野生型染色体数为26,突变型染色体数为52,直观证明突变型为四倍体。气孔统计分析表明:突变型和野生型的叶片下表皮气孔密度、保卫细胞长度也存在显著差异,突变型气孔密度比野生型降低25.29%,突变型保卫细胞比野生型长度增加32.86%。[结论]本研究获得的草棉突变型为同源四倍体,为棉花遗传育种研究和种质创新提供了有价值的材料。

[Objective]This study was aimed to obtain autotetraploid cotton plants which could steadily produce cotton bolls through the induction of diploid grass cotton plants.The study is of significance for cotton germplasm innovation and further distant hybrid genetic breeding.[Methods]The diploid cotton G.herbaceum L.was induced by improved meristem technique to obtain the tetraploid plants.The morphological,flow cytometric,and cytogenetic characteristics of mutants were analyzed and compared to that of wild type.[Results]Morphological study indicated that mutant plants displayed a significant difference(P<0.05)from parent plants with stronger growth vigor,shorter stem length,darker green and thicker leaves which became shrunken to some extent.The diameter of stem was getting bigger than that of wild type.The result of flow cytometric analysis showed the peak value of mutants and wild type at 400 and 200 respectively which indicated that DNA content of mutants was two times of the wild type.Cytogenetic results revealed 52 chromosomes in mutant plants and 26 in wild type which demonstrated the successful induction of cotton polyploid.Significant differences between the mutant and the wild type strains were also observed in stomatal density and guard cell length.The stomatal density of the mutant strain was 25.29%lower than that of the wild type strain,and the number of guard cell of the mutant strain was increased by 32.86%.[Conclusions]In our study autotetraploid plants were successfully obtained and the physiological characteristics were investigated.The results provided new valuable materials for the cotton innovation and cotton genetics and breeding studies.