红盖鳞毛蕨孢子发育的超微结构和细胞化学研究

采用透射电镜和细胞化学技术对红盖鳞毛蕨(Dryopteris erythrosora(Eaton)O.Ktze.)的孢子发育过程进行了研究,根据超微结构和细胞化学特征可将其孢子发育过程分为3个阶段:(1)孢子母细胞及其减数分裂阶段:孢子母细胞壳在孢原细胞末期开始形成,位于孢子母细胞及其减数分裂形成的四分体外侧,PAS反应显示其为多糖性质,与胼胝质壁为同功结构;在减数分裂形成的四分孢子之间产生孢子外壳,从功能、形成位置和时间上看与胼胝质壁相似,但苏丹黑B反应显示其可能含有脂类物质,与孢子母细胞壳和胼胝质壁不同。(2)孢子外壁形成阶段:外壁为乌毛蕨型(Blechnoidal-type),由薄的多糖性质的外壁内层和表面平滑的孢粉素外壁外层构成;小球参与外壁外层的形成,组织化学分析显示小球的中央区域和外壁外层内侧部分由红色(多糖)变为黄色,小球的表面区域和外壁外层部分始终被染成黑色(脂类),可知小球与外壁同步发育。(3)孢子周壁形成阶段:周壁为凹陷型(Cavate-type),包括2层,内层薄,紧贴外壁,外层隆起形成孢子脊状褶皱纹饰的轮廓,以少见的向心方向发育;苏丹黑B和PAS反应观察周壁被染成橙色,推测其可能由多糖等成分构成;孢子囊壁细胞参与周壁的形成。本研究为揭示蕨类植物孢子发生的细胞学机制提供了新资料。     

水蕨孢子囊早期发育的超微结构

利用透射电镜对模式植物水蕨(Ceratopteris thalictroides)孢子囊的早期发育进行研究.结果表明:水蕨的孢子囊是由叶片表皮的原始细胞发育而来,经过横向和纵向分裂形成外套层原始细胞和内部细胞,此过程中各个细胞内线粒体和叶绿体逐渐变大,变发达;之后外套层原始细胞继续纵分裂形成孢子囊壁细胞,内部细胞分裂形成内外两层绒毡层和孢子母细胞,此过程中电子密集物在分裂最为旺盛的细胞内体积最大,数量最多;最后孢子母细胞减数分裂形成四分孢子,此时可见孢子之间以及孢子与原生质团之间均存在着表面膜.内层绒毡层为周原质团绒毡层,外层绒毡层为腺质型绒毡层.水蕨孢子囊的早期发育属于薄囊蕨型发育.     

香鳞毛蕨配子体发育的研究

研究了香鳞毛蕨(Dryopteris fragrans (L.)Schott)配子体的发育过程。结果发现孢子极面观为椭圆形,赤道面观为半圆形,单裂缝。孢子萌发为书带蕨型;丝状体2～9个细胞长,有明显顶端细胞,可形成多细胞的广阔板状片状体;片状体顶端分生组织继续分裂,发育为幼原叶体;原叶体发育为三叉蕨型;毛状体数量丰富,均为单细胞;颈卵器和精子器几乎同时形成,较小;成熟原叶体倒卵状心脏形。该配子体表现为进化性状。     

三角鳞毛蕨配子体发育的研究

采用混合土培养三角鳞毛蕨(Dryopteris subtriangularis)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：孢子深褐色,赤道面豆形,极面观椭圆形,单裂缝。播种1周左右孢子萌发,萌发类型为书带蕨型,配子体发育为三叉蕨型。播种2周左右发育为片状体。播种4周左右发育形成幼原叶体,成熟原叶体呈心脏形。原叶体边缘及腹面均可产生毛状体,数量丰富,为单细胞。播种6周左右开始有性器官出现,精子器近圆球形,由3细胞组成,成熟颈卵器颈部由4列细胞组成,3～5层细胞高。原叶体受精后1个月内即可观察到从原叶体上生成的幼胚。     

变异鳞毛蕨的孢子培养与配子体发育研究

应用无菌培养和常规泥土培养两种方法对变异鳞毛蕨(Dryopteris varia)孢子进行了比较研究,并在光学显微镜下观察了其配子体的发育过程.结果表明:蔗糖浓度为2%的1/2MS与MS培养基对孢子萌发时间和萌发率影响不大,但前者较适于孢子萌发,而后者则适于孢子体形成;在1/2MS培养基上,1%的蔗糖浓度比其它浓度更适宜于孢子的萌发.以菜园士为培养基质时,变异鳞毛蕨孢子的萌发时间短且萌发率高,但幼孢子体出现的时间明显晚于无菌培养.孢子萌发为书带蕨型,原叶体发育为三叉蕨型,符合鳞毛蕨属配子体发育的特征.     

云南鳞毛蕨属纤维鳞毛蕨组的分类研究

本文记载云南产鳞毛蕨届纤维鳞毛蕨组植物16种,其中6种为云南新分布,1种为新改级。     

中华鳞毛蕨配子体发育过程的观察

Morphological variation during the gametophyte development process of Dryopteris chinensis ( Bak.) Koidz. was observed. The results show that the development process of D. chinensis can be divided into spore germination, filament formation, plate formation, prothallus formation, sexual organ formation and apogamety. The spores are bilaterally symmetric, monolete, surface with ridge fold ornamentation, elliptical in polar view, and approximately semicircle-shaped in equatorial view. The spore germination type is of Vittaria-type;the filaments with a length of 3-7 cells, not branched or occasionally branched, with single or double row cells; mature prothallus is symmetrically cordate, and the development type of prothallus is of Aspidium-type, with long unicellular clavate trichomes distributed on the surface and in the margin;with antheridium but archegonium is not observed, belongs to apogamety. One prothallium of D. chinensis produces one embryo, and young embryo can be generated within one month after the formation of antheridium; there are a lot of unicellular trichomes and some multicellular trichomes on the young embryo of sporophyte.     

团扇蕨是观察蕨类植物孢子囊发育的好材料

团扇蕨[Gonocormus minutus (Blume) Bosch]是观察蕨类植物孢子囊发育过程的一种好材料.以团扇蕨为材料观察孢子囊发育具有取材容易、方便确定和获得孢子囊发育的各个时期、方便进行半薄切片和观察、可代表大多数蕨类植物孢子囊发育的特点(薄囊型)等优点,可为丰富《植物学实验》的教学材料提供资料.     

同形鳞毛蕨成精子囊素系统的初步研究

研究了同形鳞毛蕨成精子囊素对该种和水蕨孢子萌发和配子体发育的影响,结果表明：同形鳞毛蕨配子体能产生成精子囊素,该成精子囊素能抑制同种孢子的萌发,抑制作用随配子体成熟度的增加而增强;同形鳞毛蕨成精子囊素还可促进同种孢子发育为雄配子体;光照条件下,同形鳞毛蕨成精子囊素对水蕨孢子萌发和配子体发育影响不大,黑暗条件下,同形鳞毛蕨成精子囊素能显著的促使水蕨孢子提早萌发,但都不影响其孢子最终萌发率和配子体的性别分化,表明同形鳞毛蕨和水蕨的成精子囊素不属于同一系统。     

阔叶鳞盖蕨和粗毛鳞盖蕨(碗蕨科)配子体发育的研究

以腐殖土为基质,对阔叶鳞盖蕨Microlepia patyphylla（D．Don）J．Sm．和粗毛鳞盖蕨M.strigosa（Thunb．）Presl进行了孢子繁殖;利用光学显微镜观察和记录了它们的孢子萌发和配子体发育过程。结果表明,两者的孢子及配子体性状极为相似：孢子同型,三裂缝,萌发慢;孢子萌发需要光,萌发方式为书带蕨型Vittaria-type;配子体生长慢,发育类型为铁线蕨型Adiantum—type;原叶体心形或其他形状,无毛状体,多数为雌雄异株。性器类型为薄囊蕨型Leptosporangiate-type。它们既具有大量的原始性状,也具有少数进化性状。与阔叶鳞盖蕨相比,粗毛鳞盖蕨的配子体发育特征更为原始。说明粗己鳞盖蕨的系统位置更加低下。首次观察到阔叶鳞盖蕨中细胞自然死亡时的叶绿体聚集现象。粗毛鳞盖蕨原叶体老化时叶绿体呈现规则的、相互镶嵌的多边形的形状以及在正常光照下粗毛鳞盖蕨某些细胞中的部分叶绿体成链珠状排列等现象。     

Plastid differentiation during androgenesis in albino and non-albino producing cultivars of barley (Hordeum vulgare L.)

In order to better understand androgenic albinism in barley, we compared plastid differentiation during anther culture in two cultivars, an albino (spring cultivar Cork) and a non-albino (winter cultivar Igri) producing cultivar. The ultrastructure of plastids and the relative amount of DNA containing plastids were followed in both cultivars during the androgenic process and correlated with the proportion of regenerated chlorophyllous plantlets. For androgenesis, anthers were collected at the uninucleate stage, during mid- or late-microspore vacuolation. At this stage DNA was detected in 15.3 ± 2. 7% of microspore plastid sections in the winter cultivar Igri, compared to 1.7 ± 0.5% in the spring cultivar Cork. In the winter cultivar Igri, starch was broken down after anther pretreatment but plastids divided rapidly during anther culture and thylakoids developed in the stroma. Prior to regeneration, plastids contained 2.0 ± 0.2 thylakoids per plastid and starch represented 26.1 ± 3.3% of the plastid volume. In the spring cultivar Cork, plastids followed a different developmental pathway. After anther pretreatment, microspore plastids differentiated exclusively into amyloplasts, accumulating starch and losing their thylakoids as well as their capacity to divide. This developmental pattern became progressively more marked, so that by the end of anther culture plastids contained 0.5 ± 0.4 thylakoids per plastid and starch represented up to 90.3 ± 4.3% of plastid volume. Following androgenesis, the response was similar in both cultivars except that the winter cultivar Igri provided 87.8% of chlorophyllous plantlets compared to 99.7% albino plantlets in the cultivar Cork. The results presented here suggest that the exclusive regeneration of albino plantlets in the spring cultivar Cork may be due to degradation of microspore plastid DNA during early pollen development, preventing the plastids from differentiating into chloroplasts under culture conditions. Received: 13 March 2000 / Revision accepted: 6 June 2000     

The genus Dryopteris in the Canary Islands and Azores and the description of two new tetraploid species

From studies in the field, botanic garden and herbarium we concluded that the following four species of Dryopteris grow on the Canary Islands: D. aemula (n = 41) so far found only on Gomera; D. pseudomas (n = 82, apogamous) similarly recorded only for Gomera; D. oligodonta (n = 41) the most common representative of the genus in the Islands is possibly an old Canary endemic related to some African species; D. guanchica a new tetraploid species ( n = 82) hitherto confused with D. austriaca (D. dilatata). On four islands of the Azores the following were found: D. aemula (n = 41); D. azorica (n = 41); D. pseudomas (n = 82, apogamous); and D. crispifolia a new tetraploid species ( n = 82) which is very distinct when living but in the dried pressed state is difficult to differentiate from D. austriaca and D. guanchica.     

A Classification Synopsis of the Genus Dryopteris from Yunnan

The genus Dryopteris of the Dryopteridaceae is one of the largest genera in pteridophytes, which contains about 300 species and is distributed throughout the world. There are about 200 species of this genus in China, of which at least 88 are present in Yunnan. In this paper, the author presents a classification synopsis of the genus Dryopteris. Subg. I Pycnopteris (T. Moore )Ching 1 species Subg. II. Dryopteris Sect. 1. Hirtipedes Fraser-Jenkins 19 species Sect. 2. Pandae Fraser-Jenkins 1 species Sect. 3. Fibrillosae Ching 18 species Sect. 4. Chrysocomae S. G. Lu 7 species Sect. 5. Caespitosae S.G.Lu 5 species Sect. 6. Pallidae Fraser- Jenkins 10 species Sect. 7. Marginatae Fraser-Jenkins 7 species Sect. 8. Splendentes Fraser- Jenkins 2 species Sect. 9. Purpurascentes Fraser- Jenkins 1 species Sect. 10. Nephrocystis H. I tô 3 species Subg. llI. Erythrovariae (H. I tô ) Fraser-Jenkins, emend. S.G. Lu Sect. 11. Erythrovariae 11 species Sect. 12. Variae Fraser- Jenkins 3 species A key to these groups is given and all the species are enumerated in the pres- ent paper.