【摘要】 本文描述甜菜(Beta vulgaris L.)大、小孢子发生及其雌、雄配子体的发育,主要结论是:1.小孢子母细胞减数分裂过程中的胞质分裂为同时型。四分孢子为四面体形。2.单核小孢子分裂为营养细胞和生殖细胞时,分裂中期的纺锤体不对称,营养核的形成稍早于生殖核。分裂末期,营养细胞与生殖细胞之间有细胞壁,而后消失。生殖细胞进一步分裂形成2个精子。成熟的花粉粒为3细胞型,营养核有解体的趋势。3.花药壁由五层结构组成:最外层为表皮,其次为药室内壁,其中层包括两层细胞,绒毡层为分泌型。4.甜菜为单子房、单胚珠、双珠被、厚珠心,曲生型胚珠。大孢子母细胞经减数分裂形成线形排列的四个大孢子。合点端大孢子具功能。5.胚囊发育属于蓼型。开花前,两极核已融合为次生核。成熟胚囊由7细胞组成。具有盲囊结构。6.同一朵花中,在前期、雄蕊的发育早于雌蕊的发育;在后期,当花粉粒成熟时,雌配子体也达到成熟,雌、雄蕊发育趋于同步。更多还原

【Abstract】 This paper describes megasporogenesis and microsporogenesis,andthe development of their female and male gametophyte in sugar beet(Beta vulgaris L.),the main conclusions are as follows:1.During the meiosis of microspore mother cell,the cytokinesis issimultaneous.The tetrad is tetrahedral.2.When the uninuclear microspore divides into a vegetative cell anda generative cell,the spindle of the metaphase is asymmetric,and theformation of the vegetative nucleus is earlier than that of the generativenucleus.At the telophase,there is a cell,then the cell wall disapp-ears.The generative cell divides further into two sperm.The maturepollen grain is 3-celled,the vegetative nucleus tends to disintegrate.3.The anther wall comprises five layers:the outermost epidermis,alayer of endothecium,2 middle layers and a tapetum being of secretorytype.4.Sugar beet is of uniovary and of uniovule being bitegeminous,cra-ssinucellate and amphitropous.After meiosis,the megaspore mother cellbecomes four megaspores arranged in a line.The chalazal megas-pore is functional.5.The development of embryo sac in sugar beet belongs to polygon-um type.Before anthesis,two polar nuclei have fused into the secon-dary nucleus.The mature embryo sac comprises seven cells and has acaecum structure.6 In the same flower,at earlier stage,the development of the stamenstarted earlier than the pistil;at later stage,when the pollen grainis matured,the female gametophyte is also matured,thus the developm-ent of the pistil and the stamen tends to synchronize.更多还原