草地早熟禾无融合生殖现象的研究
RESEARCH ON APOMIXIS IN KENTUCKY BLUEGRASS
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摘要: 本文应用石蜡切片和子房整体染色透明法研究了草地早熟禾(Poa pratensis L.)的无融合生殖现象,结果表明,草地早熟禾的胚胎发育分为两种类型。一种是由孤雌生殖形成胚,即卵细胞分裂较早形成幼胚,少数胚囊中的一个或两个助细胞也分裂较早,同时形成幼胚,但两个极核并不融合,三个反足细胞明显增大。由孤雌生殖形成胚的约占观察总数的66%,其中3%为双胚,仅一个是三胚。在成熟种子中也有两个成熟胚并生的现象。另一种是形成胚和胚乳,约占34%。34%中形成种子有两种可能的途径,一是通过有性生殖形成种子,二是由孤雌生殖形成的胚和极核受精形成的胚乳共同组成的无融合生殖种子。本研究还首次观察到早熟禾完整的双胚囊结构。Abstract: Paraffin method and whole ovary stain-clearing technique were used to study apomixis in Kentucky Bluegrass (Pea pratensis L.). The results show that embryonic development in Kentucky Bluegrass is divided into two types: (1) Embry is from parthenogenesis. Agg cells divided early and formed young embryos, one or two synergids in a few embryo-sacs divided also early and formed young embryos simultaneously. But two polar nuclei did not fuse. Three enlarged antipodal cell. The frequency of this type of embryo occupies 66% of the total, 3% of which is double-embryo and only one tri-embryo is found. There are two mature embryos in aseed. (2)Embryo and endosperm form normally. This type accounts for about 34% of the total. These 34% of seeds are formed in two possible ways in our study. One is by sexual reproduction, whereas another is by apomixis. In which seed formation with embryo and endosperm is resulted from parthenogenesis. The intact double embryo-sacs were first observed in this experiment.