南瓜未授粉子房离体培养及植株再生

以南瓜(Cucurbita moschata)未授粉子房为外植体, 在离体条件下研究了激素种类、基因型、胚囊发育时期、消毒方式和热激处理时间对胚状体诱导效果的影响, 旨在建立完善的南瓜未授粉子房离体诱导再生体系。结果表明, MS+4.0 mg·L^-1 2,4-D+0.5 mg·L^-1 NAA+1.0 mg·L^-1 6-BA和MS+0.04 mg·L^-1 TDZ两种培养基胚状体的诱导率都较高, 分别为19.8%和20.1%, 二者相比, 使用TDZ诱导更加简单; 在6个南瓜品种中, 2个生长势较强的品种(雪峰蜜本和鱷鱼南瓜)胚状体诱导率较高, 适合作为离体雌核诱导的实验材料; 开花当天的子房先切片后消毒可以有效降低愈伤组织的形成, 提高胚状体的诱导率; 在黑暗且35°C条件下热激5天有利于子房的转绿和出胚。将子叶胚转移至无激素的MS培养基上得到再生植株并移栽成活。经鉴定有7个再生植株的染色体数目n=x=22, 气孔保卫细胞叶绿体数的平均值为4.28个, 是单倍体植株。

Studies of in Vitro Culture and Plant Regeneration of Unfertilized Ovary of Pumpkin

Using unfertilized ovaries of pumpkin as explants, we determined the effect of different combinations and concentrations of growth regulators, genotypes, embryo sac development stages, disinfection methods and duration of high-temperature pretreatments on embryoid induction via in vitro culture to establish a regeneration system of unfertilized ovaries of pumpkin. The media MS+4.0 mg·L^-1 2,4-D+0.5 mg·L^-1 NAA+1.0 mg·L^-1 6-BA and MS+0.04 mg·L^-1 TDZ achieved higher induction rates, 19.8% and 20.1%, respectively, as compared to other media examined, with the TDZ-induced method easier to operate. Among the 6 pumpkin varieties tested, two (Xue feng mi ben and E yu nan gua), with stronger growth, had higher embryoid induction rates and were more suitable to be used as experiment materials. The operation of slicing and then sterilizing the ovaries picked on bloom day decreased the cavernous callus formation effectively and increased the embryoid induction rate. Treatments with darkness and heat shock (35°C) for 5 days could help ovaries turn green and induce embryoids. When moved to hormone-free MS medium, the cotyledon embryos developed to regenerated seedlings and survived after transplantation. Seven regenerated plantlets had chromosome number n=x=22 and an average number of chloroplasts in stomatal guard cells of 4.28, so they were haploid plants.