The microsporogenesis, megasporogenesis and development of female and male gametophytes of Catalpa bungei were studied by paraffin-embedded sectioning technique and whole stain-clearing technique.The results showed that there were two fertile stamens,anthers with four locules.The development of anther walls was classified as dicotyledonous,and the tapetum was of glandular heterotypic.Meiotic divisions in microspore mother cells were followed by smiultaneous cytokinesis and resulted in tetrahedral tetrad, sometimes isobilateral tetrad or decussate tetrad.The all four single nucleus pollen grains were nondisjunction and formed permanent pollen tetrads.The mature pollen grains were 2-celled and nonaperturate.The species showed superior ovary,2-1ocules,and axial placenta with many ovules.The ovule was anatropous,unitegmic and tenuinucellatae with the endothelium.The single archesporial cell functioned directly as megaspore mother cell.The meiosis of megaspore mother cell formed a linear tetrad, and the chalazal megaspore was the functional one.The development of embryo sac was of polygonum type.The development of stamen was earlier than that of pistil, they synchronized after blossom.It was considered that the barrenness of Catalpa bungei was not due to male or female sterility,although some proportional abortion exist in the development of pistil and stamen.Maybe it was related to pollination, fertilization and post embryonic development.%运用石蜡切片法和整体透明法对楸树(Catalpa bungei C.A.Meyer)大、小孢子发生及雌、雄配子体发育过程进行了研究.结果表明:楸树可育雄蕊2枚,花药4室,药壁发育属双子叶型,腺质异型绒毡层.小孢子母细胞减数分裂为同时型,四分体后小孢子不分离形成正四面体型四合花粉,偶有左右对称型和十字交叉型.成熟花粉为二细胞型,无萌发孔.子房上位,2室,中轴胎座,胚珠多数,倒生,单珠被,薄珠心,具珠被绒毡层.单孢原直接发育为大孢子母细胞,四分体线形排列,合点端大孢子发育为功能大孢子,胚囊发育为蓼型.雄蕊发育早于雌蕊,花开后雌、雄蕊趋于同熟.研究认为:虽然楸树雌、雄蕊发育过程中均存在一定比例的败育,但其"花而不实"并非雄性或雌性不育所致.推测与其授粉受精和胚后发育有关.
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