Abstract: Nucellar behavior of polyembryonic rice strain AP Ⅳ and monoembryonic variety IR36 was studied by using the technology of GMA serial sections and ultrathin-sections. The results showed that the nucellus cell was growing with degenerating from the formation of megasporocyte to some days after fertilization in AP Ⅳ and IR36. Before zygote division, the growing of nucellus cell occupies a dominant position. So, many dividing cells can be found in the nucellus. These nucellus cells expanding but with little cytoplasm, which were much different from the meristematic cells, could not divided further. After zygote division, degeneration of nucellus accelerates and almost all nucellus cell disappeared in 4-5 days after fertilization except for the most outside peripheral cells. A low frequency of abnormal nucellar growth was observed in APⅣ, but no embryo developed from nucellus cell was found under natural condition. ReplaceFont('ChDivSummary','通过ＧＭＡ切片和超薄切片技术对多胚水稻品系ＡＰⅣ和单胚品种ＩＲ３６珠心组织的行为进行研究表明，两份材料的珠心组织从大孢子母细胞形成开始到受精后数天，处于边生长边退化状态，在合子分裂前，以生长为主，此期间在珠心组织内可观察到许多具分裂相的细胞，这些细胞膨大但细胞质很少，与具备分生能力的细胞完全不同，无法进一步分裂；合子分裂以后珠心组织退化加速，到受精后４～５ｄ，珠心组织除了其表皮细胞外，其他几乎都解体了。ＡＰⅣ珠心组织出现低频率异常生长的现象，但未观察到在自然条件下由珠心细胞发育形成的不定胚。');ReplaceFont('EnDivSummary','Nucellar behavior of polyembryonic rice strain AP Ⅳ and monoembryonic variety IR36 was studied by using the technology of GMA serial sections and ultrathin-sections. The results showed that the nucellus cell was growing with degenerating from the formation of megasporocyte to some days after fertilization in AP Ⅳ and IR36.Before zygote division, the growing of nucellus cell occupies a dominant position. So, many dividing cells can be found in the nucellus. These nucellus cells expanding but with little cytoplasm, which were much different from the meristematic cells, could not divided further. After zygote division, degeneration of nucellus accelerates and almost all nucellus cell disappeared in 4～5 days after fertilization except for the most outside peripheral cells. A low frequency of abnormal nucellar growth was observed in APⅣ, but no embryo developed from nucellus cell was found under natural condition.');if(document.getElementById('ChDivSummary') != null && document.getElementById('ChDivSummary').innerHTML!=""){CutSpan('ChDivSummary',500);DisplaySpanDiv('ChDivSummary');ClearSummaryOnLoad('SummaryLinkChID','SummaryLinkEnID');} if(document.getElementById('EnDivSummary') != null && document.getElementById('EnDivSummary').innerHTML!=""){CutSpan('EnDivSummary',1000);DisplaySpanDiv('EnDivSummary');ClearSummaryOnLoad('SummaryLinkEnID','SummaryLinkChID');}ReplaceChar1('ChDivSummary');ReplaceChar('ChDivSummary');ReplaceChar1('EnDivSummary');ReplaceChar('EnDivSummary');

Key words: adventitious embryo, embryology, nucellus, polyembryony

摘要： 通过GMA切片和超薄切片技术对多胚水稻品系APⅣ和单胚品种IR36珠心组织的行为进行研究表明，两份材料的珠心组织从大孢子母细胞形成开始到受精后数天，处于边生长边退化状态，在合子分裂前，以生长为主，此期间在珠心组织内可观察到许多具分裂相的细胞，这些细胞膨大但细胞质很少，与具备分生能力的细胞完全不同，无法进一步分裂；合子分裂以后珠心组织退化加速，到受精后4~5 d，珠心组织除了其表皮细胞外，其他几乎都解体了。APⅣ珠心组织出现低频率异常生长的现象，但未观察到在自然条件下由珠心细胞发育形成的不定胚。

关键词: 多胚现象, 不定胚, 珠心组织