高粱SSA-1无融合生殖胚胎学研究

经常规石蜡切片法，在光学水平观察了高粱（Ｓｏｒｇｈｕｍ ｂｉｃｏｌｏｒ （Ｌ．） Ｍｏｅｎｃｈ） ＳＳＡ－１ 无融合生殖的胚胎发生。高粱ＳＳＡ－１ 的无融合生殖为无孢子生殖和二倍体孢子生殖两种类型。两种生殖类型的单核胚囊经３ 次有丝分裂形成７ 细胞（８ 核）的成熟胚囊，由卵细胞、２ 个助细胞、２ 个极核和３ 个反足细胞组成。反足细胞迅速分裂增殖，形成由２０—３０ 个细胞组成的细胞团。此外，还具有一定频率的无孢子生殖多孢原和多胚囊现象。在未授粉情况下，卵细胞自发分裂形成典型的禾本科类型单子叶胚。经切片统计表明，ＳＳＡ－１ 的无融合生殖频率为４２％ ，证明该系为一兼性无融合生殖系。文中还讨论了ＳＳＡ－１ 无融合生殖过程的特点。

EMBRYOLOGICAL STUDY ON APOMIXIS IN A SORGHUM LINE SSA 1

The Developmental process of apomictic embryo sac and embryo in a sorghum (Sorghum bicolor (L.) Moench.) line SSA 1 was observed under light micrascope, using the method of conventional paraffin sectioning.The result showed that the apomictic development conforms apospory and diplospory.The uninucleate embryo sac underwent mitotic divisions for three times to form a seven celled or eight nuclei mature embryo sac including an egg, two synergids, two polar nuclei and three antipodals.The antipodals divided and multiplicated to form an antipodal mass.Moreover, aposporous multiarchesporial cells and multiple embryo sacs were infrequently observed.Without pollination, the egg divided autonomously to form a typical graminaceous mature embryo.The authors counted the apomictic sections in the whole sections and the result showed that the frequency of apomixis was 42%, indicating the facultative apomictic property in the line SSA 1.The characteristics of apomictic process in the line SSA 1 is also discussed.