太白红杉小孢子的发生和雄配子体的发育

太白红杉(Larix chinensis Beissn)的雄球花7月初开始分化。小孢子囊壁一般包括5～6层细胞：表皮、药室内壁、2～3层中层和绒毡层。绒毡层属于周原质团型。造孢细胞在7月下旬形成,8月上旬形成小孢子母细胞,8月下旬开始减数分裂,于10月上旬进入双线期,并以双线期渡过休眠。翌年3月下旬解除休眠继续进行减数分裂,4月中旬形成四分体,4月下旬到5月初小孢子从四分体内释放出来,小孢子经过连续4次有丝分裂后,于5月中旬形成5-细胞型的成熟花粉粒（雄配子体）并开始散粉。小孢子母细胞发育表现出不同步现象,部分小孢子母细胞在发育过程中出现退化,在小孢子囊内形成空腔。     

太白红杉小孢子的发生和雄配子体的发育

太白红杉(Larix chinensis Beissn)的雄球花7月初开始分化。小孢子囊壁一般包括5～6层细胞：表皮、药室内壁、2～3层中层和绒毡层。绒毡层属于周原质团型。造孢细胞在7月下旬形成,8月上旬形成小孢子母细胞,8月下旬开始减数分裂,于10月上旬进入双线期,并以双线期渡过休眠。翌年3月下旬解除休眠继续进行减数分裂,4月中旬形成四分体,4月下旬到5月初小孢子从四分体内释放出来,小孢子经过连续4次有丝分裂后,于5月中旬形成5-细胞型的成熟花粉粒(雄配子体)并开始散粉。小孢子母细胞发育表现出不同步现象,部分小孢子母细胞在发育过程中出现退化,在小孢子囊内形成空腔。     

濒危植物水松小孢子发生和雄配子体发育的研究

水松(Glyptostrobus pensilis)是我国特有的单种属孑遗植物,是极度濒危物种,被列为国家一级重点保护植物。为了从生殖生物学方面探讨水松的濒危机制,采用石蜡切片法对水松小孢子发生及雄配子体发育过程进行了系统地观察研究。结果表明:水松雄球花于10月中旬开始分化,11月初小孢子囊壁形成,12月初小孢子母细胞形成,12月中旬减数分裂。翌年1月中旬形成四面体形和左右对称形四分体,1月下旬四分体解体,释放出游离小孢子。2月中旬花粉粒发育成熟,并以二细胞形态进行传粉,散粉期约为2周左右。3月萌发花粉管,3月下旬出现精原细胞、管核和不育核,5月下旬花粉管到达颈卵器顶部,精原细胞分裂成两个精细胞。水松小孢子和雄配子体发育过程中败育和变形现象很少,据此我们认为,水松小孢子发生与雄配子体发育正常,不是致其濒危的主要原因。     

南方红豆杉小孢子发生与雄配子体发育

采用石蜡切片法,对南方红豆杉小孢子发生及雄配子体发育过程进行了系统地观察。结果表明：南方红豆杉小孢子叶球于7月下旬分化,9月中旬形成造孢细胞,11月初形成小孢子母细胞;同一小孢子叶球中的小孢子母细胞表现出发育不同步现象;11中旬,进入减数分裂时期,形成游离小孢子后休眠越冬,于翌年1月下旬逐渐成熟,成熟花粉粒为单核;2月中下旬开始散粉,散粉时间持续15 d 左右。花粉落入胚珠后,经过3次分裂形成管细胞、柄细胞和2个精子;管细胞和柄细胞最终退化解体,未见花粉败育现象。认为南方红豆杉小孢子发生与雄配子体发育正常,不是致其濒危的主要原因。     

侧柏小孢子的发生和雄配子体的形态

侧柏［Ｐｌａｔｙｃｌａｄｕｓｏｒｉｅｎａｌｉｓ（Ｌ．）Ｆｒａｎｃｏ］初生造孢细胞在８月下旬（１９９２年）形成,１１月上旬形成小孢子母细胞,１９９３年２月中旬形成四分体,２月下旬从四分体内释放出来,３月中旬成成熟花粉并开始传粉,４月上旬花粉粒在珠心上萌发,５月上旬生殖细胞分裂,６月上旬精原细胞分理解。     

云南松雌雄配子体的发育

云南松(Pinus yunnanensis Fr.)雄配子体于10月在小孢子叶腹面产生二个小孢子囊,内有许多进行分裂的造孢组织细胞。第二年一月下旬至二月初小孢子母细胞进行减数分裂。在分裂期间,细胞内所贮存的淀粉粒的分布发生变化。二月初四分体小孢子形成,绒毡层细胞解体。二日中旬单核花粉粒形成,外壁扩展形成二个异极对称的气囊。三月花粉在四细胞时期散发。 雌配子体于二月上旬在珠心皮下分化出孢原细胞。二月下旬大孢子母细胞进入减数分裂期。三月初直列四分体大孢子形成,珠孔端三个退化,合点端一个功能大孢子进入有丝分裂期,形成约32个游离核的配子体。次年三月初雌配子体形成,四月初中央细胞核分裂,四月底颈卵器成熟,卵核周围产生辐射状原生质纤丝。五月初受精开始。云南松雌雄配子体的发育与亚热带分布的P.roburghii相似。     

越南篦齿苏铁小孢子发生及其系统学意义

运用常规石蜡切片方法,结合显微荧光技术对越南篦齿苏铁Cycas elongata 小孢子发生和花粉个体发育进行了研究。结果表明：其小孢子叶球5月中下旬开始萌动,小孢子囊着生在小孢子叶远轴面,且3-5小孢子囊以辐射状排列方式聚生成聚合囊。小孢子囊壁由6-7层细胞组成,包括表皮、中层及绒毡层。绒毡层来源于成熟造孢组织的外围细胞,其退化形式为分泌型。6月中旬,小孢子母细胞进入减数分裂I,至6月下旬形成四分体。母细胞减数分裂后胞质分裂的方式与其他苏铁类植物不同,具有连续型与同时型两种类型。7月中旬,小孢子经过2次有丝分裂后,形成3细胞的成熟花粉粒。7月下旬进入散粉状态。在花粉发育过程中,母细胞内淀粉粒的积累及其壁上胼胝质的沉积均呈现规律性变化。     

沙田柚雌雄蕊发育及其相关性研究

沙田柚为例生胚珠,双珠被,厚珠心,具多个孢原细胞,其中之一发育形成大孢子母细胞,四个大孢子呈直线形排列,功能大孢子居合点端,胚囊发育为蓼型,珠孔端有珠心冠。 花药为四分孢子囊,小孢子母细胞减数分裂过程中,胞质分裂为同时型,四分小孢子四面体型,成熟花粉粒为二细胞型。 同一朵花中,雌雄蕊发育的相关性是:当大孢子母细胞形成时,小孢子进入单核期。当雌蕊发育进入大孢子时期,双核花粉粒形成。大孢子和双核花粉粒都在开花前10天左右形成,雌雄蕊同时成熟。     

小蓬草的胚胎学研究

对小蓬草（Conyzacanadensis）大小孢子发生、雌雄配子体形成、受精、胚及胚乳发育过程进行了研究,主要结果如下：花药四室,药壁由表皮、药室内壁、中层和绒毡层组成。表皮退化;药室内壁宿存,细胞柱状伸长,纤维状加厚;中层细胞退化较早,在小孢子母细胞减数分裂开始时仅存残迹;绒毡层于小孢子母细胞减数第一次分裂前期开始原位变形退化,属于腺质型绒毡层;小孢子母细胞减数分裂为同时型,四分体的排列方式主要为四面体形和左右对称形;成熟花粉粒多为3-细胞花粉粒,偶见2-细胞花粉粒。子房下位,2心皮,1室,单胚珠,基生胎座;单珠被,薄珠心,倒生胚珠,具发达的珠被绒毡层。珠心表皮下分化出大孢子孢原细胞,孢原细胞直接发育为大孢子母细胞,大孢子母细胞减数分裂形成4个大孢子直线形排列,仅合点端的大孢子发育成功能大孢子母细胞,胚囊发育为蓼型。两个极核在受精前融合为次生核,珠孔受精。胚乳发育属于核型,胚胎发育为紫菀型;具胚乳吸器。     

长白落叶松生殖生物学特性研究──Ⅰ．球花芽分化与早期发育

本文研究了长白落叶松（ＬａｒｉｘｏｌｇｅｎｓｉｓＨｅｎｒｙ）大小孢子叶球的分化及其分布规律．获得如下结果：（１）６月下旬芽鳞形成期终止,７月初进入小孢子叶分化期,７月未至８月上旬小孢子叶分化期结束．８月上旬进入小孢子囊分化期,８月下旬出现造孢细胞,９月中旬形成小孢子母细胞．１０月底小孢子母细胞保持在细线期阶段,小孢子叶球进入冬季休眠期．（２）９月初苞片原基开始形成,９月中旬珠鳞原基形成;１０月上旬出现胚珠原始体,１０月下旬大孢子母细胞形成,１０月底大孢子叶球芽进入冬季休眠．（３）小孢子叶球芽主要分布在树冠的中、下部．数量上远远大于大孢子叶球芽的数量,约为大孢子叶球芽的１９倍。大孢子叶球芽主要集中分布在树冠中部,而且树冠下部多于树冠上部。     

红松配子体的发育过程

红松是我国主要用材树种,材质优良。我国主要分布在长白山和小兴安岭,随着森林工业的发展,大面积的原始森林迅速减少,人工更新日趋重要。在生产中采用种子育苗,因此对红松种子的发育规律应全面掌握,以便为种子园建立、良种选育采取有效措施提供理论依据。根据国内外有关报导,红松雌雄配子的形成、受精作用已有一定的研究^[14、15],但这些研究只侧重在小孢子母细胞的减数分裂和受精作用。故对雌雄配子体的发育过程仍需深入研究,尤其是授粉后的雄配子体发育和精子进入颈卵器的过程,均未见详细报导。     

Development of male gametophyte of <Emphasis Type="Italic">Larix</Emphasis><Emphasis Type="Italic">leptolepis</Emphasis> Gord. with emphasis on diffuse stage of meiosis

A basic developmental framework of the Larix leptolepis Gord male gametophyte is presented in detail by squashing technique. The duration of the meiosis stage was more than 6 months, and included a long diffuse stage during winter. This long duration of the diffuse appearance of the diplotene stage makes L. leptolepis a unique suitable experimental material for studying the structure and function of the diffuse stage of meiosis. In particular, the processes of desynapsing and unpairing, which so far have received little attention, can be examined in detail. In L. leptolepis, the chromosomes undergo a dramatic structural reorganization during the diffuse diplotene stage. Based on the clearly visible differences in chromosome morphology, the diffuse diplotene stage was divided into four periods with suggested nomenclature as follows: schizonema, pre-diffuse diplotene, diffuse diplotene and post-diffuse diplotene. Both simultaneous and successive microsporogenesis were observed within L. leptolepis, and there was no strict relationship between the microsporogenesis types and the tetrad configurations, which are strongly influenced by spindle orientation, especially during meiosis II. The mature pollen grain at pollination consists of five cells aligned in an axial row. The prothallial cells cannot be regarded as senescent cells because they remain capable of division. S.-G. Zhang and W.-H. Yang have contributed equally to this work.     

华北落叶松小孢子母细胞(PMC)减数分裂和花粉的发育

采用染色体压片法系统地观察了华北落叶松Larix principis-rupprechtii小孢子母细胞(PMC)减数分裂的细胞学特征和花粉发育过程。结果表明:华北落叶松PMC减数分裂始于当年秋季,以弥散双线期的特殊状态休眠越冬,次年春天又重新恢复其后续的减数分裂过程。主要特点是在同一花药中,减数分裂不同步,且各阶段分裂速度较快,3天内全部停留在四分体阶段;二价体构型主要为两臂共发生过两次以上交换的环形二价体,少数细胞中偶见一臂发生交换的棒状二价体;其平均构型为10.62II 1.38II;中期II核分裂相既有平行式样,又有互为垂直式样,形成左右对称型和四面体型四分体,兼具单、双子叶植物四分体主要类型特点。四分体持续一周后,细胞壁开始溶解,4个小孢子分离并游离在药室中,成为独立的单核花粉。其后细胞核开始有丝分裂,最后形成由2个原叶细胞、1个管细胞、1个柄细胞和1个体细胞共5个细胞组成的成熟花粉。此外,还观察到成熟花粉当中有13.6%是由4个细胞组成的。     

革苞菊胚胎学研究 Ⅰ.大、小孢子发生和雌、雄配子体发育

革苞菊为雌雄异株。在雄花中 ,花药 4室 ,药壁发育为双子叶型 ,由表皮、药室内壁 ,一层中层和绒毡层组成。绒毡层于小孢子四分体时期开始变形 ,其细胞原生质体向药室中移动 ,为变形绒毡层。小孢子孢原为多细胞 ,小孢子母细胞减数分裂产生四面体型的小孢子四分体。四分体胞质分裂为同时型。成熟花粉 3-细胞型。单核期的小孢子出现壁发育不良和巨大及空花粉现象。在雌花中 ,胚珠是倒生的 ,单珠被 ,薄珠心 ,珠被于孢原期已发育完整。大孢子孢原单细胞。由孢原细胞直接发育形成大孢子母细胞。 4个大孢子直线型 ,蓼型胚囊。于成熟胚囊期观察到发育异常的胚囊。通过对胚囊发育过程中营养物质消长规律的研究 ,讨论了环境与发育的相关性问题。     

Embryological Studies of Codonopsis pilosula Nannf.

This paper reports the studies of megasporogenesis and microsporogenesis, development of female and male gametophytes, fertilization, and development of embryo and endosperm, The anther wall consists of four layers, i.e. epidermis, endothecium, middle layer and tapetum. Part of the tapetum cells originates from the primary parietal cells, and the other part comes from the basic tissue of the anther partition. Tapeta? cells are uninucleate or binucleate, and belong to the secretory type. Microsporocyte originates directly from the primary sporogenous cell, Cytokinesis is of the simultaneous type. Arrangement of microspores in tetrad is isobilateral. Mature pollen grain is of the 2-celled type. The ovary is tricarpellum, trilocular with many ovules. The ovule is mono-integinous, tenui-nucellar and anatropous. The embryo sac originates from the single-archesporial cell. The one chalazal megaspore in linear tetrad is the functional megaspore. The development of embryo sac is of the Polygonum type. Before fertilization, two polar nuclei fuse in to a secondary nucleus and the antipodal cells degenerate. Fertilization is porogamy, fusion of one sperm with secondary nucleus is faster than that of one sperm with egg nucleus. The development of endosperm is of the cellular type. The first three divisions of endosperm ceils are regular. Two endosperm cells near the ends of chalaza and the micropyle develop into haustorium without division. The haustoria gradually degenerate at the late stage of globular embryo. The mature seeds contain abundant endosperm. The development of embryo is of the Solanad type. The suspensor consists of 12–20 cells. The optimum development of the suspensor is at the early stage of the globular embryo. It begins to degenerate after late globular stage. The embryo develops from proembryo, heartshaped embryo, dicotyledenous- to mature embryo.     

ULTRASTRUCTURE AND DEVELOPMENT OF THE NEXINE AND INTINE IN THE POLLEN WALL OF SILENE ALBA (CARYOPHYLLACEAE)

Nexine and intine development in Silene alba (Caryophyllaceae) was investigated by electron microscopy and enzyme cytochemistry. Nexine-2 forms by deposition of sporopollenin along unit membrane lamellae closely associated with the microspore plasma membrane in the late tetrad stage. After the callose wall dissolves, electron density increases along the tangentially oriented fibers of the proximal primexine, forming nexine-1. When the exine is essentially complete, the intine begins to develop. In the nearly mature microspore, acid phosphatase activity appears in the peripheral cytoplasm just prior to its extrusion into the intine of the mature pollen grain.     

A Contribution to Pollination and Fertilization of Amentotaxus argotaenta

The present investigation was conducted during 1980–1982, and mater- ials collected from Jin-Fo shan (Golden Buddha Mountain), at a height of 1400-1600 m, Sichuan province, China. Pollination of Amentotaxus argotaenia began to proceed last week of May, and came into bloom the first week of June. The male strobiles were almost entirely wilting at June 12–15. Thus, florescence of Amentotaxus spread over a period of 3 weeks. While the pollen grains approaching to maturity, most of the microspores divide to form a larger tube cell and a smaller antheridial initial. In this case the mature pollen grains of Amentotaxus consist of two cells. Then pollen grains are attracted down into the pollen chamber in the apex of the nucellus after pollination. The pollen chamber of Amentotaxus in longitudinal section looks like a flask in shape and is very much similar to that of Ginkgo biloba. As pollen grains at pollen chamber begin to germinate, the antheridial initials divide again to give rise to a spermatogenous cell and a sterile cell. At first, the spermatogenous cell is of a size only 11–13 μ in diameter. When the pollen tube reaches the middle part of the nucellus, the spermatogeneous cell is of a size about 30 μ. In the middle of July, pollen tube approaches the top of the female gametophyte. In this time, the spermatogenous cell has already been mature enough and is of 58–85 μ in diameter. The nuclei of spermatogenous ceils, 30–36 μ in size, are usually lying in the lateral side of the cytoplasm at its micropylar end. From the middle to the end of July, spermatogenous cells divide to form two unequal sperms, one of which is larger than the other and is the functional one. The large sperm is almost round in shape and about 56 μ in diameter. The small sperm is elliptic in shape, non-functional, and about 33 μ in diameter. The nuclei of the large and small sperms are about 40 μ and 26 μ, respectively. In some cases there are lateral pollen tube and sperms in the ovules of Amentotaxus, or the pollen tube even grows toward the lower part of female gametophyte in the chalazal end and there are well developed sperms in such a case. In the middle of July, nucleus of the central cell divides to form a ventral canal nucleus and an egg nucleus. The former then breaks down quickly and the latter continues to develope and moves toward the central part of the egg cell gradually. It is interesting to note that there are a number of nucleolus-like grains in the cytoplasm of the egg cell in Amentotaxus. The large nueleolus-like grains contain a larger central vacuole with several smaller vacuoles surrounding it. These grains show a positive reaction and blue colour by PAS and aniline blue black or coomassie brilliant blue, respectively. The above facts show that the nucleolus-like grains contain not only po- lysaccharides, but also protein. Similar grains may also found in the developing pollen tube. This is a unique feature in Amentotaxus and even in Gymnosperms. Otherwise, there are often two groups of the dense cytoplasm under the egg nucleus in Amentotaxus. Fertilization of Amentotaxus took place around July 20–29 (1980–1982). Interval between pollination and fertilization was about two months. After male nucleus fuses entirely with the female nucleus, the zygote begins to divide by mitosis. During fertilization, in addition that the large sperm enters the egg cell and fuses with the egg nucleus, the small sperm, tube nucleus, and sterile cell are often delivered into the egg cell. But they are disintegrated gradual]y and eventually. It is worthy to note that the nucleolus-like grains and the starches in pollen tube are also released into the egg cell. Then enlargement, fusion, and budding in the nucleolus-like grains may be found within the cytoplasm of the egg cell after fertilization. The history of investigating Amentotaxus found in 1883 has been lasting a long period of 100 years. But researches in sex production has never been studied before. The present work has shown that fertilization in Araentotaxus is very much similar to that in Taxus, Pseudotaxus, and Torreya. In other words, they all belong to the same type, that is, mitosis of zygote taking place after fusion of the two sexual nuclei. This condition constitutes one of the features of Taxaceae. But fertilization in Cephalotaxaceae is different from that of Taxaceae in having mitosis taking place before fusion of the two sexual nuclei. Pollination of Amentotaxus is similar to that of Cephalotaxus with dual-cell pollen grains at shedding stage. On the other hand, interval between pollination and fertilization in Austrotaxus lasts for 13.5 months, and this is the longest one in Taxaceae, and it is similar to that of Cephalotaxus proceeding for 14 months. To sum up, from the point of view of pollination, fertilization, and embryogenesis, Amentotaxus could be considered a primitive type in Taxaceae. Perhaps an order of systematic position of the genera belonging to Taxaceae can be arranged thus: Amentotaxus, Austrotaxus, Taxus, Pseudotaxus, and Torreya. And Cephalotaxaceae may be related to Taxaceae by way of Amentotaxus.     

太白红杉雌配子体的形成、受精、胚胎发育及其系统学意义

太白红杉(Iarix chinensis Beissn)雌球花于7月中下旬开始分化,9月上旬至9月中旬形成大孢子母细咆,10月中旬,大孢子母细胞进入休眠期。翌年4月底至5月初解除休眠,大孢子母细胞进行减数分裂,于5月10日左右形成直列四分体,随后珠孔端的3个大孢子退化,合点端的1个大孢子进一步发育,成熟卵细胞于7月初受精;花粉管将内含物释放入卵细胞后在尾部形成浓密物质沉淀;受精后,合子被染色较深的新细胞质所包围,并发现存在多精入卵的现象。合子经过两次连续有丝分裂,产生4个游离核后伴随新细胞质一起移至合点端,接着同时进行一次有丝分裂产生8个核,并分成上下两层后形成细胞壁,但上层细胞顶部不形成细胞壁。原胚发育属于松型。在幼胚阶段,我们发现部分胚珠发育异常,其雌配子体有的变为半透明状,有的则干瘪萎缩。太白红杉具简单多胚和莲座胚。9月中旬,成熟胚形成,成熟胚具5～6枚子叶。太白红杉从雌球花花芽分化到胚胎成熟历时14个月。