核桃无融合生殖的细胞胚胎学研究

以40%～70%饱和度硫酸铵分级沉淀、DEAESepharoseiCL-6B、SephadexG-100、羟基磷灰石、PhenylSepharoseCL-4B和制备电泳分离纯化了小麦的尿卟啉原合酶(UROS)。酶的亚基分子质量为54ku,全酶分子质量为66ku,酶的等电点6.3,在pH8.2时比活为257μmol/(mg·min),最适反应温度40℃,5mmol/L的巯基乙醇和Mg2+促进酶活,纯化的小麦UROS在-20℃下0.1mol/L,pH8.5的Tris-HCl,内含质量分数为50%的甘油,5mmol/L的巯基乙醇和MgCl2中贮藏7d酶活损失90%。

A cytoembryological study on apomixis in walnut ( Jugians regia L.)

The developmental process of apomictic embryo in three walnut ( Juglans regia L.) varieties was observed under light microscope,using the method of conventional paraffin sectioning.The result showed that there was an ovule in the female flower of walnut and the embryo sac of walnut was a typical eight nuclei Polygonum embryo sac including an egg,two synergids,two polar nuclei and three antipodals.Apomictic embryos of three walnut varieties came from non fertilized egg cell in the mature embryo sac and they belonged to parthenogenesis of egg cell.The eggcell divided autonomously formed two cell primary embryos,multiple cell primary embryos,and globular embryo to mature embryo.The endosperm cell was formed by two polar nuclei fusion and division.Two synergids and three antipodals were aborted in the developing process of egg cell and endosperm cells.