峨眉鱊的生物学资料及个体发育的观察

2004年9月~2005年10月对峨眉(Acheilognathus omeiensis)的生物学特性及个体发育进行了初步研究。峨眉为杂食性,栖息于水流较缓的水体中,其适宜的生活温度为4~28℃。1龄即性成熟;婚姻色和第二性征8月下旬开始出现,10月下旬更为明显,此时雌雄性腺均处于Ⅲ期;产卵期为翌年2月上旬至5月上旬,此时输卵管的长度为6.68~22.54 mm(12.539±4.810mm,n=50)。分批产卵,成熟卵量为26~219粒,平均为115粒;非成熟卵量为121~709粒,平均为243粒。产卵时对蚌有明显的选择性,仅将卵产于杜氏珠蚌(Unio douglasiae)的鳃瓣中。峨眉的个体发育分为蚌中发育和出蚌后发育两个时期,依其发育的形态特点,进一步将其生活史粗略地分为胚胎期、仔鱼期、稚鱼期、幼鱼期和成鱼期5个时期,分别记述了各期外部形态和内部器官的变化。     

樟子松大孢子的发生和雌配子体的形成过程

樟子松大孢子母细胞经一系列变化,发育成雌配子体。在哈尔滨地区樟子松大孢子母细胞于每年6月8～14日形成,接着进行减数分裂,于6月16～20日形成大孢子。随着大孢子核的分裂,进入游离核时期,并于次年5月28日～6月4日形成细胞壁,幼雌配子体中出现颈卵器原始细胞,它分裂一次形成颈细胞和中央细胞。6月7～9日中央细胞分裂成卵细胞和腹沟细胞,6月13～15日颈卵器发育成熟。成熟的颈卵器含有颈细胞、腹沟细胞和卵细胞,但颈细胞和腹沟细胞已经退化。     

裸子植物种子的胚乳由何而来?

答:裸子植物胚珠里的胚囊内有许多个颈卵器生长于配子体组织中,每个颈卵器中有一个大型的卵细胞,没有极核细胞,卵受精后发育成胚(其中有一个发育成熟,其余的败育).胚乳是由雌配子体——成熟的胚囊发育而来的。这种现象有别于被子植物双受精后形成的胚     

猪蛔虫卵在北京地区自然条件下的发育期和生命力的研究

1.实验证明,在北京地区的自然坏境中猪蛔虫卵从4月至10月都能进行发育,5月至9月间能发育成侵袭性幼虫期卵。在背阳光条件下为6月至8月。实验证明,各期虫卵都能够越冬,并且保持侵袭能力。 2.虫卵发育速度最快的月份为7、8两月,土层深度为3—20厘米。土层的温度范围为24.5—39℃(平均26.3—33.3℃),含水量为9.5—19%。虫卵可于2星期内发育至侵袭性幼虫期卵。 3.实验证明,在北京地区,散布在土层3厘米以上的虫卵,由于湿度过低(含水量5%以下)或温度过高(42.5℃以上),造成虫卵不能发育成侵袭性幼虫期卵。但在背阳的条件下,在7、8月份的流行季节里,土表层由于温度、湿度均较适宜,虫卵能完全发育成侵袭性幼虫期卵。 4.在北京地区,在3厘米以下的土层,平均温度不超过33.3℃、含水量不小于9%时,虫卵有89%能发育成侵袭性幼虫期卵。 5.根据实验结果,对猪蛔虫病的防治问题进行了讨论。     

西藏飞蝗的生物学特性

西藏飞蝗Locusta.migratoria tibetensis Chen在四川甘孜州1年发生1代,某些地方(乡城县)1年发生不完整的2代,即以卵越冬,翌年3月下旬开始孵化出土,4月中、下旬为孵化盛期,1~3龄始盛期为4月中旬~5月中旬,高峰期为5月下旬,7月上旬初始羽化,7月下旬~8月上旬为羽化盛期,8月上旬始见产卵,8月下旬~9月上旬为产卵盛期,第1代成虫较早产下的卵块在条件适宜的情况下可于当年9月上旬孵化出土,但孵化出的蝗蝻不能越冬。该虫卵、全蝻期及全世代的发育起点温度分别为14.2,16.1,14.6℃,有效积温为179.1日.度、360.0日.度、787.8日.度。在18,21,24,27和30℃等5种恒温条件下其平均世代历期214.4,133.3,79.2,66.3和50.7d。     

极危孑遗物种东方水韭雌配子体及胚胎的解剖学观察

以人工培养的国家一级保护植物东方水韭(Isoetes orientalis)为材料,采用切片技术对雌配子体和胚胎的发育进程进行解剖学观察研究,探讨其有性生殖过程及濒危机制。结果表明:(1)东方水韭大孢子3~5d萌发,成熟雌配子体呈球形,无假根,三裂缝处发育出多个颈卵器,成熟颈卵器只有颈壁细胞与颈沟细胞,无腹沟细胞。(2)多数雌配子体只发育出一个胚胎,偶见多胚共存现象;胚胎发育时期,第一叶原基相比第二、三叶原基发育迅速。(3)颈卵器部分组织常出现分化紊乱,导致雌配子体败育。该研究结果支持"根叶理论",并讨论了腹沟细胞的退化以及双胚共存机制,认为东方水韭雌配子体常停留在游离核阶段、颈卵器形态或位置不规则、卵细胞排列紊乱等可能是其败育的原因。     

日本蹄盖蕨配子体发育的研究

采用混和土培养日本蹄盖蕨(Athyrium niponicum)孢子,显微镜下观察记录其孢子萌发及配子体发育过程。结果表明:孢子黑褐色,赤道面豆形,极面观椭圆形,单裂缝。播种7 d左右孢子萌发,萌发类型为向心型,配子体发育为铁线蕨型。丝状体7~11细胞时开始发育为片状体。播种14 d后发育形成幼原叶体,成熟原叶体呈心脏形。原叶体边缘可产生单细胞毛状体。播种后20 d左右精子器出现,精子器近圆球形,由3细胞组成。7 d后颈卵器出现,成熟颈卵器3~5层细胞高。精卵受精后14 d左右即可观察到从原叶体上生成的幼胚。     

黄杨绢野螟生物学特性、发育起点和有效积温测定及在防治上应用

黄杨绢野螟在上海地区一年发生3～4代,以第四代2～3龄幼虫越冬,翌年3月中旬至10月中旬为发生危害期。测定了其各虫态发育起点和有效积温,其中卵期发育起点为7.3±0.5℃,积温为94.9日度;全世代发育起点为15.3±10℃,积温为879日度。依据发育起点和积温,推算出上海地区防治最适期为每年5月29日至6月8日,7月5日至7月14日,8月5日至8月13日,9月28日至10月1日。并验证了推算结果,可在防冶中应用。     

乌毛蕨配子体发育的研究

采用混合土培养乌毛蕨（Blechnum orientale）孢子,显微镜下观察记录其孢子萌发及配子体发育过程。结果表明：孢子黑褐色,赤道而豆形,极而观椭圆形,单裂缝。播种1周左右孢子萌发,萌发类型为书带蕨型,配子体发育为叉蕨型。丝状体5—10细胞时开始发育为片状体。播种2周后发育形成幼原叶体,成熟原叶体呈心脏形。原叶体边缘及表面均可产生毛状体,数量丰富,为单细胞。播种后1个月左右开始有颈卵器出现,成熟颈卵器颈部由4列细胞组成,3—5层细胞高。精子器产,扛时间较颈卵器早10d左右,精子器近圆球形,由3细胞组成。精卵受精后2周左右即可观察到从原叶体上生成的幼胚。     

银杏胚珠发育进程的解剖学研究

以15 a生银杏(Ginkgo bilobaL.)品种‘佛指’(G.bilobacv.‘Fozhi’)为材料,观察了授粉后胚珠结构、雌配子体发育和种皮分化形成的过程。结果表明:(1)授粉后2 d胚珠已分化出珠心、珠被和珠托组织,珠被顶端形成直径为162.16μm的珠孔与540.54μm长的珠孔道,珠心组织顶端形成长约520.83μm、最大直径约125.06μm的瓶状贮粉室,花粉粒经珠孔道已到达贮粉室并在其中停留;(2)雌配子体的发育先后经历了游离核阶段(授粉后5~30 d)和细胞化阶段(授粉后30~45 d),之后在近珠孔端形成颈卵器,其余部分发育为胚乳薄壁细胞,其营养物质的积累高峰期为授粉后60~80 d;(3)种皮分化与形成分别经历珠被分化期(授粉期至授粉后30 d)、种皮分化期(授粉后30~50 d)、种皮形成初期(授粉后50~80 d)、种皮形成期(授粉后80~90 d)。     

野生胭脂花(Primula maximowiczii)生长发育和花芽分化研究

以北京东灵山胭脂花自然分布地野生群体中2年生以上植株为研究对象,于2008～2010年连续3年观测了野生胭脂花的年生长发育进程,并采用石蜡切片法制片,通过普通光学显微镜和体视显微镜观察了胭脂花花芽分化和花序发育的过程,以探明野生胭脂花生长发育和花芽分化的规律,为人工栽培胭脂花提供依据。结果显示:(1)胭脂花的年生长发育进程可分为萌芽期、营养生长期、开花期、果实发育期、果熟期、花芽分化期和休眠期等7个阶段;5～9月为胭脂花的生长季,生长环境凉爽,日平均气温为5℃～20℃。(2)胭脂花花芽分化期为7月中下旬～9月上旬,历时约2个月,整个过程包括未分化期、花芽原基分化期、小花原基分化期和小花分化期;花序上的小花由外向内逐渐形成并发育,雌雄蕊的发育从8月中下旬开始到9月上中旬结束;花序发育完全的胭脂花植株进入休眠期,经过当年10月份至来年4月份的低温阶段翌年开花。胭脂花花芽分化进程和外部形态密切相关,可根据植株的外部形态特征快速判定花序发育状况。     

The Gametophytes and Fertilization in Pseudotaxus

The development of the gametophytes and fertilization of Pseudotaxus chienii Cheng has been investigated. Pollination first occurred on April 17 (1964). The pollen grains shed at the uninucleate stage and germination on the nucellus is almost immediate. The pollen tubes approached the freenucleate female gametophyte about May 5. The spermatogenous cell is continuously enlarging with the growth of the pollen tube and two unequal sperms are formed after its division. Occasionally the small sperm may divide further into two smaller ones. During pollination the megaspore mother cell is in meiosis and 3 or 4 megaspores are formed. Generally 2 or 3 megaspores at the micropylar end are going to degenerate while the chalaza] megaspore is rapidly enlarging. After 8 successive simultaneous divisions of the functional megaspore 256 free nuclei are resulted and they are evenly distributed at the bulge of the famale gametophyte. Then the wall formation follows. Sometimes there are more than two, even as many as 5–6 gametophytes developed within a single ovule. The archegonial initials become differentiated at the apical end of the female gametophyte. They are usually single and apical, rarely lateral in position. The number of the archegonia vary from 3 to 7, usually 4–6. There are 2–8 neck cells in each archegonium which is surrounded by a layer of jacket cells. The central cell divided about May 20–26 (1964) and the division of the central cell gives rise to the egg and the ventral canal nucleus, the latter being degenerated soon. There are many proteid vacuoles near the nucleus of the matured egg. The fertilization took place about May 23–26 (1964). At first, the pollen tube discharges its contents into the egg, then the larger sperm fuses with the egg nucleus in the middle part of the archegonium. At the same time the male cytoplasm also fuses with the female cytoplasm and a layer of densely-staining neocytoplasm is formed around the fused nucleus. The smaller sperm, tube nucleus and sterile cell usually remain in the cytoplasm above the egg nucleus for some time. Based upon the observations of the development of the gametophytes and fertilization the authors conclude that Pseudotaxus is more close related to Taxus than any other member of Taxaceae.     

Seasonal anatomical variations in the testes of European pike, Esox lucius L.

The seasonal development of the testes in European pike was examined using wild fish and biopsies from pike housed in tanks. The size of the tubules and the different cell types were measured and their histological appearance described. Four stages of development can be distinguished during the annual cycle. They are: (I) the stage of rest from June to August; (II) the stage of development from September to November with intensive spermatogenesis; (III) the stage of maturity from December to March/April with spermatogenesis completed; and (IV) the post-spawning stage from March to May.     

蕨配子体发育及卵发生的显微结构观察

运用显微观察技术对蕨(Pteridium aquilinum var. latiusculum)配子体发育和卵发生进行了研究。结果表明：(1)蕨孢子黄褐色,四面体形,具三裂缝,接种后3～7 d萌发,经丝状体和片状体阶段发育成原叶体,成熟原叶体雌雄异株或同株。(2)蕨颈卵器产生于生长点下方的表面细胞(颈卵器原始细胞),该细胞经2次分裂形成3层细胞,其上层和下层细胞发育为颈卵器壁细胞,中间细胞为初生细胞,它经2次不等分裂产生3个细胞,分别为卵细胞、腹沟细胞和颈沟细胞;刚产生时,此3个细胞紧贴颈卵器壁,细胞质内液泡较多,随着发育,卵细胞和腹沟细胞之间产生了分离腔,但二者通过孔区相连,在卵细胞上表面可观察到卵膜;此后,颈沟细胞和腹沟细胞逐渐退化,颈卵器壁细胞内具有黑色颗粒物质。连续切片观察发现,成熟卵细胞上表面中央具有受精孔。卵发生的细节尚需超微结构的研究。     

Fertilization in Pinus Bungeana

Pinus bungeana is a species endemic to China and as yet its embryology has not been reported. The present paper deals with its process of fertilization in some details. 1. The development of the male gamete and the structure of the archegonium. The spermatogenous cell has already divided into two uniqual male gametes in the middle of May (in 1978, at Peking), about ten days before fertilization. Both sperms are spheroidal to ellipsoidal. The larger sperm is about 94 × 65 μm and the smaller one, about 72 × 58 μm in size. As the pollen tube approaches the archegonium the two sperms move toward the apex of the tube together with the remaining contents. Generally the larger sperm precedes the smaller one. The cytoplasmic contents also contain a sterile cell, 3—43×2—29 μm in size and a tube nuleus, 15—30 μm in diamter, besides the sperms. A mass of starch grains of more or less similar to sperm in size is also included in the contents of the pollen tube. Generally 3—4, even up to 7–8 pollen grains germinate normally within an ovule. Therefore, many sperms (up to 14—16) may be present on the same nucellus. The archegonium is elongato-ellipsoidal, about 870 ×500 μm in size. Arehegonia are single, 2—(3—5) in number, with 2 neck cells and a layer of jacket cells. The central cell divided in the middle of May and gave rise to the ventral canal cell and the egg. As the archegonium matures the cytoplasm becomes radiate fibrillae around the egg nucleus. The egg nucleus is large, 150—226 μm in diameter. One large nucleolus, 22—25 μm in diameter and sometimes up to 50; small nueleoli are present within the nucleus. 2. Fertilization Pollination takes place in the first week of May and fertilization will be effected from the end of May to the first week of June of next year. The interval between pollinatin and fertilization in P. bungeana is about thirteen months and the lapse of time is almost similar to most of the Pinus so far recorded. When the pollen tube contacts the archegonium through the neck cells all its contents are discharged into the egg cell. Usually the larger sperm fuses with the egg nucleus and the rest of the contents stays in the upper part of the egg cell. It is interesting to note that the nonfunctional second sperm also moves toward the egg nucleus and often divides by mitosis; and this phenomenon is not reported elsewhere. At the earlier stage of the fusion between male and female nuclei the male nucleoplasm is dense and finely granular while the female nucleoplasm is thin and coarsely granular, hence the boundary between them is very clear. The nuclear membranes of both nuclei persist for a long time. After the male nucleus sinks into the female nucleus completely, both nuclei begin to divide and enter into the prophase and then the metaphase simultaneously. By this time the paternal and maternal chromosome sets with their spindles still remain at certain distance from each other. Then the paternal chromosomes with their spindle move gradually toward the maternal ones. At first a multipolar common spindle appears as the maternal and paternal spindles with their chromosomes merge together. Finally a regular bipolar spindle is formed and both the maternal and paternal chromosomes become arranged on the equatorial plate. In the meantime, the process of fusion is complete and the zygote is at the stage of metaphase. At the moment the spindle looks greater in width than in length, being about 80×65—70 μm in size. 3. Supernumerary nuclei and sperms. The ventral canal cell degenerates soon after its formation. While the supernumerary sperms divide usually after their entrance into the egg cell. Therefore, the supernumerary nuclei probably derive directly from the smaller sperms or indirectly from mitoses of the larger ones Generally the nucleoplasm of the supernumerary nuclei is rather thin while the nucleoplasm of the undivided sperms is rather dense. This shows that the former is in the state of degeneration. The supernumerary nuclei of P. bungeana are as many as 7, their usual size being 43—58×32—43 μm. In the upper part of some egg cells there are still secondary smaller sperms about the size of 36 × 29 μm, Their volume is just about half of the usual smaller sperm. Probably they are derived from the division of the smaller sperms.     

Investigation on Sexual Reproductive Cycle in Torreya grandis

Before May the first, the ovular primordium of Torreya grandis has differentiated. From this early moment the primordium look like the parabolic form and it is surrounded by many pairs of scales, of which a pair of the inner scales are lying at the same level as the primordium of ovule. About May the first of the second year, the differentiation of the various tissues in the ovule has essentially completed. And the fertilization takes place from the end of August to the beginning of September. After overwintering, the proembryo developes into a young embryo in April of the third year, and at the last stage both the seed and the embryo become mature from September to November. In the Taxaceae, the embryogenesis is similar in Amentotaxus,Austrotaxus, Taxus, and Pseudotaxus; their proembryos form cell wall all at the stage of 16-free nuclei and simple polyembryony is common among them. In Torreya, however, the cell wall of proembryo appear at the stage of 4 or 8-free nuclei, and cleavage polyembryony is its feature. On the basis of our observation, the sexual reproductive cycle of Torreya grandis seems to have two important features, one of which is rather long (31 moths from ovular primordium to seed maturity; about 4 months from pollination to fertilization and 7-8 months for development of proembryo). The state of the long sexual cycle in Amentotaxus and Austrotaxus is different from each other; in the former development of young embryo lasts 10-11 months, and in the latter the interval between pollination and fertilization is 13.5 months. The second feature of the sexual cycle in Torreya grandis is over two winters: development of the sporogenous cells in the first, and the proembryo development in the second. From the point of view of phylogenesis, some primitive characters are present in the sexual cycle of Torreya grandis although a specialized feature of the embryogenesis occurs in some degree.     

Development of Gametophytes in Fokienia Cupressaceae

The structure of the ovule and the development of the gametophytes in Fokienia, an endemic genus of Cupressaceae are described in some detail. Two wings, one small and one large, are developed along the micropylar end of the ovule and two resin canals are present in each of them. The material collected in the middle of April was already pollinated and the pollen began to germinate on the nucellus. The sterile cell, tube cell and spermatogenous cell have been formed in the tube in the first collection of April 17. At the end of June the division of the spermatogenous cell results in two sperms of Similar size and shape and the division plane is usually parallel to long axis of the pollen tube. Both sperms are effective in fertilization. 4096 free nuclei (actual counting, 3733—4224 ones) are produced through 12 times of repeated divisions of the functional megaspore, then cell walls appear among the free nuclei and cellular female gametophyte is formed. The number of archegonia varies from 6 to 16, mostly 9–12. The archegonial complex is enclosed by 2–3 layers of jacket cells. The neck cells are usually 4 in number, arranged in 1–2 layers. The central cell divides and results in the formation of one ventral canal nucleus and one egg nucleus. Fertilization takes place in the middle of the archegonium. The development of the gametophytes of Fokienia is more or less similar to that of Sabina.     

Developmental synchronization of male and female gametophytes in Ginkgo biloba and its neck mother cell division prior to fertilization

This study investigated male and female gametophytes in Ginkgo biloba, while a droplet of fluid was present in the fertilization chamber and found that the central cell, the generative cell and the neck mother cell divided simultaneously prior to fertilization. In male gametophytes, the generative cell divided to yield two sperm cells. Concomitantly, the two neck mother cells of the archegonium increased in size then divided asymmetrically resulting in two big cover cells and two small base cells. Each cell had a fixed end in direct contact with an adjacent jacket cell and a free end overlapping its counterpart. This unique arrangement could allow for their free ends to swing into the fertilization chamber as a result of the force from the interior of the archegonium where a polar periclinal division had occurred to produce a canal cell and an egg. The subsequent withdrawal of the content of the archegonium may facilitate the entry of sperm into the archegonium. The neck apparatus closed after the fertilization occurred. The concurrence of the above divisions and the delicate structure of neck apparatus suggest that the gametophytes undergo a synchronization process to become receptive at the time of fertilization. However, the formation of neck cells and the opening time of neck apparatus of the archegonia within the same ovule were slightly different, which could lead to the formation of zygotes at a temporally distinct interval. The earlier formed zygote may progress as the only mature embryo in the ovule.     

蝶兰胚珠的cDNA文库构建及其特异基因表达的研究

以蝶兰(Phalaenopsis“Mt.Kaala”cv SM9108)为材料,分别提取大孢子母细胞时期胚珠和成熟胚珠的PolyA RNA,反转录成cDNA,构建起两个cDNA文库。克隆筛选采用差异杂交法。从上述两个cDNA文库中,各选择一个筛选出的cDNA,对其在植物体不同器官和不同发育时期的胚珠内的表达进行了分析。结果表明该两个cDNA均为胚珠特异,并且分别在胚珠发育的特定时期表达。推测该两个cDNA的表达受胚珠内部的不同因子调控。     

Archegonium and fertilization in Coniferopsida

Key message

This paper reviews studies on the origin and development of the Coniferopsida’s archegonium, illustrates the relationship between the archegonium and fertilization, and discusses the molecular regulation of archegonium development.

Abstract

This paper reviews studies on the origin and development of the Coniferopsida’s archegonium and discusses the characteristics of the archegonial cells and the molecular regulation of archegonium development. There are some main conclusions which could be drawn from this review. (1) It enables the precise position of the archegonium in the ovule to be determined as well as its structural features. (2) The functions of the neck cells in Coniferopsida are that they may serve as channels for sperms to enter the archegonia and lead the growth of pollen tubes. (3) The proteid vacuoles in egg cell may provide nutrition for fertilization and lead to the paternal inheritance of plastids in some Coniferopsida. (4) The uniparental transmission of plastids results from “the active digestion of male organelle nuclei (genomes) in young zygotes” in almost all Coniferopsida. (5) The studies on the molecular regulation of the archegonium and fertilization in Coniferopsida are still very limited and that is the direction for further research. In summary, the review provides a theoretical basis for further study on the developmental and reproductive biology of the Coniferopsida.