不结球白菜小孢子胚胎发生过程及发育途径研究

采用FDA荧光染色法对小孢子游离培养的发育过程进行了观察。结果表明:不结球白菜花粉母细胞减数分裂释放出的小孢子发育到单核靠边期及稍后时期染色最深、活力最强。多数游离小孢子培养经历的发育过程与合子胚相似,并且胚胎发育迅速,6～9 d产生大量球型胚,13 d开始出现子叶型胚胎。小孢子胚胎发育途径既有对称分裂并产生胚胎的途径(B途径),也有第1次不对称有丝分裂的方式;第1次不对称分裂后,既有营养细胞单独发育成胚的现象(A途径),也有营养细胞和生殖细胞共同发育成胚的现象(E途径),但未发现生殖细胞单独发育成胚的现象。

Studies on microspore-derived embryogenesis and developmental pathway in non-heading Chinese cabbage

The microspore embryogenesis of non-heading Chinese cabbage(Brassica campestris ssp.chinensis Makino)was studied using fluorescence staining technique with FDA(fluorescein diacetate).The late uninucleate stage microspores had the highest viability and exhibited the densest dyeing.The development of most microspore-derived embryos was similar to that of the zygotic embryos,but they grew faster than zygotic embryos.Globular embryos were grown into after 6-9 days of microspore culture,and cotyledonary embryos after 13 days.We found three division patterns of microspores in sporophytic pathway.There were two patterns in the first mitosis of microspore:one was asymmetrical division,and the other was symmetrical division.Two identical or similarly sized cells were formed from the symmetrical division,and divided repeatedly to form an embryo(named B pathway).After the first asymmetrical division,both the vegetative and generative cells could be induced to generate embryos(named E pathway),or only the vegetative cells could be induced,but not the generative cells(named A pathway).