结球白菜下胚轴原生质体培养及其体细胞胚植株再生

结球白菜（Brassica campestris ssp．pekinensis）的原生质体培养由于基因型依赖性强，细胞易褐化，愈伤组织的芽诱导率低等而难于再生植株。本实验以结球白菜的下胚轴原生质体为试材，研究了影响其细胞分裂及愈伤组织形成的因素，探索了经过体细胞胚发生途径获得再生植株的技术。结果表明，试材的基因型及培养基组成影响细胞分裂及褐化；KM8P是结球白菜原生质体培养更适宜的培养基，能显著减轻细胞的褐化；液体培养基中一定浓度的活性炭能在一定程度上减轻细胞褐化进程，并有利于星状细胞团的形成；基因型Asko中，愈伤组织形成体细胞胚的结构，其发生的频率约为5％，该类体细胞胚能全部顺利地发育成完整植株。本技术具有再生植株形成容易、频率较高且通过体细胞胚发生途径等优点。

The Protoplast Culture of Brassica campestris ssp. pekinensis and Plant Regeneration via Somatic Embryogenesis

Some factors blocking the protoplast regeneration of Brassica campestris ssp. pekinensis include genotype-dependent cell browning and low frequency of shoot induction. Screening for a genotype that is easy to culture and establishing an experimental system for efficient shoot induc- tion will greatly benefit the genetic innovation of B. campestris ssp. pekinensis via somatic hybridization. Hypocotyl protoplasts of several varieties of B. campestris ssp. pekinensis were cultured, and factors influencing cell division and browning were studied. Cell division and brown- ing were influenced heavily by genotypes of materials and the culture media used. KM8P medium effectively reduced the browning tendency of the cells and was a good medium for protoplast culture of B. campestris ssp. pekinensis. Activated charcoal had a specific function of reducing cell browning and promoting the star-shaped microcalli formation. The somatic embryos were observed on calli of the genotype Asko in shoot-inducing medium containing 3 mg.L-1 AgNO3, with a frequency of about 5%. Intact plants were developed easily from the embryos. This proce- dure has advantages in easily regenerating plants with relatively high frequency via a somatic embryogenesis pathway.