碎米藓属两种藓类植物孢子萌发与原丝体发育特征研究

为获取其孢子萌发类型与该属植物系统发育、生态选择以及生殖策略选择的相关性,该研究通过室内人工培养的方式,在微米量级下观察并描述了碎米藓属(Fabronia)碎米藓(F.pusilla)和东亚碎米藓(F.matsumurae)两种藓类植物孢子萌发、原丝体发育和配子体发生的过程。结果表明:(1)两种藓类植物孢子均为壁外萌发,均产生由1~15个半圆球形细胞组成的绿丝体(chloronema)短枝;(2)碎米藓在绿丝体顶端分化产生轴丝体细胞,东亚碎米藓未分化产生轴丝体(caulonema);(3)两种藓类植物配子体原始细胞均在绿丝体上分化产生。参照Nishida对藓类植物孢子萌发型划分标准,分析并确定了碎米藓属两种藓类植物孢子萌发型均为蓑藓型(Maromitrium-type),为碎米藓属的系统分类提供了发育学证据。     

梨蒴珠藓孢子萌发与原丝体发育特征研究

为了解梨蒴珠藓（Bartramia pomiformis）孢子萌发和原丝体发育特征,在显微镜下观察室内人工培养的梨蒴珠藓单倍配子体发育过程。结果表明,梨蒴珠藓孢子吸水膨胀5 d后,开始破壁萌发,原丝体系统以丝状绿丝体为主,轴丝体在绿丝体上分化产生。培养22 d后,配子体在轴丝体细胞上分化产生。参照Nishida的标准,梨蒴珠藓孢子萌发类型为真藓型（Bryum-type）。这为梨蒴珠藓的人工扩繁提供了发育学基础资料。     

大帽藓(Encalypta ciliata Hedw.)原丝体发育特征的实验研究

在人工培养大帽藓(Encalypta ciliata Hedw．)孢子的基础上,对其孢子萌发、原丝体发育及配子体发生的全过程进行行了观察、描绘和照相。实验结果表明：在大帽藓的原丝体系统中主要包括两种成分,即：粗短的丝状绿丝体和细长的柳枝状轴丝体。丝状绿丝体一般由4～6个短粗柱状细胞组成,而轴丝体则是由多数细长柱形细胞构成,其上间隔分布有2～5个细胞组成的棒状体,初生假根有或者无。同时,还对大帽藓原丝体发育的特征进行了分析和讨论,初步确定大帽藓孢子萌发属于新的孢子萌发类型——大帽藓型(Encalypta-type)。     

尖叶拟船叶藓原丝体发育特征研究

将尖叶拟船叶藓[Dolichomitriopsis diversiformis(Mitt.)Nog.]孢子接种于Knop培养基上,置于恒温培养箱中培养,在光学显微镜下对其原丝体(protonema)发育特征进行了详细观察和记录。结果表明:孢子第2天就开始萌发,第6天时其萌发率达90%以上;原丝体系统由绿丝体(chloronema)和轴丝体(caulonema)构成,假根(rhizoides)产生于芽体基部,由轴丝体退化而成;配子枝原始细胞产生于绿丝体分枝的基部或轴丝体上的斜壁细胞;配子枝(game tophore)形成后其上各部位都可形成假根;孢子萌发类型为真藓型(Bryum-type)。     

大帽藓(Encalypta ciliata Hedw.)原丝体发育特征的实验研究

在人工培养大帽藓(Encalypta ciliata Hedw.)孢子的基础上,对其孢子萌发、原丝体发育及配子体发生的全过程进行了观察、描绘和照相。实验结果表明:在大帽藓的原丝体系统中主要包括两种成分,即:粗短的丝状绿丝体和细长的柳枝状轴丝体。丝状绿丝体一般由4～6个短粗柱状细胞组成;而轴丝体则是由多数细长柱形细胞构成,其上间隔分布有2～5个细胞组成的棒状体,初生假根有或者无。同时,还对大帽藓原丝体发育的特征进行了分析和讨论,初步确定大帽藓孢子萌发属于新的孢子萌发类型——大帽藓型(Encalypta-type)。     

小扭口藓(Barbula indica)芽胞发育特征的实验研究

在光照培养箱中人工对照培养小扭口藓(Barbula indica(Hook.) Spreng)的芽胞,显微镜下观察并记录其发育成配子体的全过程。结果表明:小扭口藓芽胞在3~4 d即可萌发;10 d左右开始分化出绿丝体、轴丝体及假根;18 d,轴丝体上的侧枝顶端细胞以分生缢割的方式产生单细胞或多细胞芽胞;40 d,轴丝体上开始出现配子体原始细胞;之后,配子体原始细胞发育成桑椹状的幼小配子体。还对芽胞形态发育、生理生态及配子体发生过程的特点进行了分析和讨论。     

波叶仙鹤藓的孢子培养及发育生物学研究

首次成功地进行了人工条件下波叶仙鹤藓(Atrichum undulatum(Hedw.)P.Beauv)单细胞孢子的培养,并详细研究、拍摄了其植物体(配子体)形态发育的全过程。孢子无后熟或体眠期,3-4天即可萌发,萌发率可达95％以上;培养10天左右绿丝体系统、轴丝体系统及假根开始分化,约40天开始出现芽体原基,50天芽体陆续形成,80天左右植物体完成营养生长,开始性器发育。初生假根发育不良,基原细胞不分裂,由绿丝体产生轴丝体的方式复杂,轴丝体细胞分裂面有球形和斜向、横向三种,芽原基分化时,首先在轴丝体上产生光合能力很强的细胞群,其基部产生芽原基,芽原基的分化成功率仅有50％左右,芽体形成后,原丝体系统多枯萎或特化为假根。并就波叶仙鹤藓的形态发育、生理生态、生殖和进化等方面也进行了理论探讨。     

中华缩叶藓孢子萌发与原丝体发育特征研究

通过室内人工培养中华缩叶藓的孢子,在光学显微镜下详细观察了其孢子萌发、原丝体发育及配子体发生的全过程.结果表明:中华缩叶藓的孢子在壁内萌发,随后分裂产生块状原丝体;块状原丝体上可产生两种丝状体,一种是具疣的棒状原丝体,另一种是由长圆柱状细胞组成的轴丝体;配子体原始细胞只产生于块状原丝体上.根据中华缩叶藓的孢子萌发和原丝体发育特征,并参照Nishida对藓类植物孢子萌发类型的划分,确定中华缩叶藓的萌发孢子型应属于缩叶藓型(Ptychomitrium-type).     

仙鹤藓的孢子萌发及愈伤组织诱导

通过对采自河北雾灵山海拔1500m的仙鹤藓（Atrichum undulatum）的孢子萌发以及原丝体发育的观察,发现仙鹤藓孢子无休眠现象,孢子接种3天左右萌发：其原丝体发育分为绿丝体和轴丝体两个阶段。扩大培养实验结果表明。仙鹤藓茎叶体在添加2％葡萄糖的MS培养基上,置于25℃／20℃、14小时光照/10小时黑暗、36μmol·m^-2·s^-1条件下培养．产生新生茎叶体最多,且茎叶体长势最好,可以获得大量无菌材料。仙鹤藓愈伤组织诱导实验显示,形成愈伤组织的最佳培养基为添加2％葡萄糖和1．0mg·L^-16-BA的MS培养基。     

烟气对泥炭藓孢子萌发影响的模拟研究

适量烟气能促进种子萌发,但对苔藓植物孢子的作用尚不清楚.选取采自长白山区泥炭地的粗叶泥炭藓和中位泥炭藓的孢蒴为试验材料,通过燃烧泥炭地植物产生烟气,制备烟溶液,分别与不同大小(大:直径为2.10～2.50 mm;小:直径为1.50～1.90 mm)以及不同保存时长(旧:4.3和6.3年;新:0.3年)的孢蒴进行两组双因素试验,经不同时长的烟溶液浸泡和萌发试验,模拟研究烟气、孢蒴大小和保存时长对苔藓植物孢子萌发的影响.结果表明: 烟溶液浸泡影响孢子萌发,培养10 d时,不同时长的烟溶液浸泡均可使孢子的萌发率提高5倍以上,小孢蒴孢子的萌发率高;培养21 d时,仅适度浸泡(3 d)表现出促进萌发的作用,孢蒴大小对孢子萌发率无影响;烟溶液浸泡对长时间保存(4.3和6.3年)的孢蒴孢子萌发无促进作用.研究表明,适量烟气可加速新泥炭藓孢子以及小孢蒴孢子的萌发.在存在不定期火烧干扰的泥炭地中,与对种子植物的作用类似,烟气可能在苔藓植物种群的有性更新和种群维持中发挥重要作用.     

Effect of the energy supply on filamentous growth and development in Physcomitrella patens

The filamentous gametophyte of the moss Physcomitrella patens consists of two filament types called chloronemata and caulonemata. Chloronemal cells are photosynthetically active with numerous chloroplasts, while caulonemata help to spread the colony by radial growth. The balance between the two filament types is affected by external factors such as light and plant hormones. In the present study, caulonema formation and chloronemal branching have been monitored during high and low light conditions and in the presence of glucose, auxin, or cytokinin. These experiments were performed both in a wild-type strain and in a hxk1 knockout mutant which lacks the major hexokinase of Physcomitrella. It was found that caulonema formation is induced by high energy conditions such as high light and external glucose, while chloronemal branching is stimulated by low energy conditions such as reduced light, and in the hxk1 mutant. The hxk1 mutation also causes buds to appear on chloronemal filaments, which is rarely seen in the wild type, and shows increased sensitivity to cytokinin and abscisic acid. Based on these findings a model is proposed in which the energy supply of the moss colony regulates the balance between chloronemal and caulonemal growth.     

A Study on the Spore Morphology of Bryum Hedw. in China

Spore morphology of thirteen species of the genus Bryum Hedw. were observed by LM and SEM. The results show that the ornamentation of spore exine could be divided into three types: Type I , blunt at the top of baculate processes, to which four species belong: Bryum argenteum, B. lonchocaulon , B. uliginosum and B. arcticum. Type Ⅱ, sharp or with small processes at the top of baculate processes, represented by seven species: B. pallescens, B. caespiticium, B. pallens, B. pseudotriquetrum, B. paradoxum, B. alpinum and B. thomsoii. Type Ⅲ, expanded into hemispherical-shaped at the top of baculate processes, represented by two species: B.coronatum and B.sauteri. The Bryum species may also be divided into three groups according to the variation of spore diameter. Group I , with spore diameter under 10 μm, including one species, B. uliginosum. Group Ⅱ, with spore diameter 11～20 μm, including seven species: B. argenteum, B. alpinum, B. coronatum, B. pallens, B.paradoxum, B.sauteri, B.thomsonii. Group Ⅲ, spore diameter 21～30 μm, with five species: B. pallescens, B. caespiticium, B. pseudotriquetrum, B. lonchocaulon, B. arcticum. There are resemblances of spore morphology and exine ornamentation among the thirteen species. In the view of palynology, the genus Bryum is a natural taxon which is more advanced than the genus Pohlia Hedw. But spores of thirteen species are different at some characters such as diameter, shape ofproximal leptoma, etc., which indicates the genetic differentiation in the genus Bryum.     

Induction of budding on chloronemata and caulonemata of the moss,Physcomitrella patens,using isopentenyladenine

The bud-inducing effect of the cytokinin N⁶-(²-isopentenyl)-adenine (i⁶-Ade) was examined in the moss Physcomitrella patens growing in liquid culture. Under these conditions, buds could be induced on chloronemata as well as on caulonemata. By application of i⁶-Ade, bud-formation was accelerated in both types of tissue. The number of buds, their size and their site of development were dependent on the concentration of the cytokinin in the range of 10^-7 M to 10^-5 M. Moreover, the percentage of caulonema cells increased with a cytokinin concentration of 10^-5 M. These results indicate that chloronema cells may also function as target cells for exogenous cytokinins. The composition of proteins from caulonemata and chloronemata of two different species (P. patens and Funaria hygrometrica), grown on solid medium were compared. No differences could be detected between the protein patterns of caulonemata and chloronemata of the same species while between the two species the differences were obvious.Abbreviations i⁶-Ade N⁶-(²-isopentenyladenine) - Da dalton - SDS-PAGE sodium dodecyl sulfate-polyacrylamide gel electrophoresis     

Forced calcium entry and polarized growth of Funaria spores

We have used both steady electric fields, and gradients of the divalent ionophore, A23187, to control the point at which rhizoids emerge from spores of the common moss Funaria hygrometrica. The spores were grown in a medium containing calcium nitrate as the only major salt. Spores tend to form rhizoids towards the positive electrode, with a half maximal response to a difference of 4–8 mV across each cell. They also tend to form rhizoids towards the end of higher ionophore concentration in response to A23187 gradients. Both of these responses are the same at pH 5.5 and 8.0. Our tentative explanation is that Funaria spores tend to form rhizoids where most calcium enters. However, the point of chloronema emergence is scarcely affected by steady fields of up to 45 mV/cell. Moreover, when steady fields are applied across already developed rhizoids or chloronemata, their subsequent growth is directed towards the negative electrode in both cases, with rhizoids giving a 50% response at only 3—5 mV/cell, and chloronemata being less responsive.From Tsung-Hsien Chen's Ph.D. thesis, Purdue University     

龙头节肢蕨配子体发育的研究

采用原生境土、Knorp’s营养液和MS培养基的培养方法对龙头节肢蕨(Arthromeris lungtauensis Ching)的孢子进行对照培养,观察其孢子萌发和配子体发育过程。结果：孢子黄色,呈二面体型,赤道面观为肾形,极面观椭圆形,周壁瘤状,有刺,单裂缝;接种5 d后孢子开始萌发,萌发为书带蕨型（Vittaria-Type),原叶体的发育为槲蕨型(Drynaria-Type）;接种7 d后向丝状体发育,为3~8个细胞长;接种2周后向片状体发育,片状体呈长阔匙形,达6~8纵列细胞;接种6周后向原叶体发育,成熟的原叶体呈对称心形,毛状体二型（单细胞乳头状的毛状体和4~5个细胞分枝的毛状体）和假根分叉;接种9周后出现精子器,早于颈卵器1周出现和成熟;精子器具宽而短的柄,颈卵器的颈沟部较短而且通常弯曲。研究表明龙头节肢蕨的配子体发育过程中出现毛状体,假根分叉,颈卵器弯曲等进化特征,并对其分类学意义初步讨论。     

槲蕨配子体形态发育的研究

用无机培养基和土壤培养基分别培养槲蕨(Drynaria roosii Nakaike)孢子,显微镜下观察孢子萌发及配子体形态发育过程.结果表明:孢子黄色,具单裂缝,赤道面观豆形,极面观椭圆形,不具周壁,孢子外壁局部具大小不一的颗粒状纹饰.接种后10～12 d孢子萌发,萌发类型为书带蕨型,原叶体发育为槲蕨型.接种后20 d左右发育为片状体,片状体形成顶端细胞的时间较晚.毛状体出现在片状体形成之后,数量丰富,多为单细胞,分布于原叶体背腹面及边缘.接种后60 d左右发育形成幼原叶体,成熟原叶体呈心脏形.接种后65 d左右开始有性器官出现,精子器的出现较颈卵器早10 d左右.颈卵器成熟后,颈部常向原叶体基部倾斜或弯曲.原叶体受精后幼胚突破颈卵器生长.     

假鞭叶铁线蕨配子体发育的研究

用1/2MS培养基培养假鞭叶铁线蕨(Adiantum mdesianum Chatak)孢子,光学显微镜下观察孢子萌发及配子体发育过程.结果表明:成熟的孢子棕红色,不透明,四面体型,辐射对称,三裂缝.接种6 d左右孢子萌发,萌发类型为紫萁型(Osmunda-type),原叶体发育为铁线蕨型(Adiantum-type).接种25 d左右片状体形成.接种50 d左右发育为成熟原叶体,呈心脏形,裸露无毛状体.接种60 d左右性器官出现,雌雄同株.精子器长圆球形,由3细胞构成;成熟颈卵器颈部由4列细胞组成,3～5层细胞高.     

Protonemal Morphogenesis of the Moss Tetraphis pellucida Hedw. in Culture and in the Wild

In axenic culture, the protonemal filaments of Tetraphis pellucidaderived from either spores and gemmae, or excised stems andleaves, share a mixture of attributes of chloronemata and caulonemata.Indirect immunofluorescence reveals that the tip cells containcortical and endoplasmic arrays of microtubules at interphase,and phragmoplasts associated with cell plate formation, butpre-prophase bands are absent. Protonemal plates originate fromthe same sites as filamentous protonemal side branches or directlyfrom young gemmae or excised stem fragments. These plates havea cylindrical base, the latter producing a single gametophorebud, and a unistratose lamina. The gametophores produce gemmacups in culture with the vegetative life cycle taking approximately28 d. Gibberellic acid (GA₃) has no visible effect on protonemal morphogenesiswhereas the auxin naphthalene acetic acid (NAA) suppresses plateand side branch formation. In the presence of kinetin the platesare callus-like and produce supernumerary buds. Abscisic acid(ABA) induces malformed plates and filaments with swollen cells,similar to those found in ageing cultures. Rhizoids are produced in abundance from gametophores and protonemalplates in nature but were never seen in culture. In the wild,rhizoids produce numerous protonemal plates and occasional gametophorebuds. The former are the main source of new shoots. The filamentousprotonemal phase in nature mainly comprises upright filamentscontaining one or more abscission cells. The protonemal plates in Tetraphis are homologous with thosein the allied genus Tetrodontium but are very different fromthose in Diphyscium and Sphagnum. Differences between cultureand nature are attributed to lower nutrient levels and irradiancesin the wild. Tetraphis pellucida, protonema, moss, morphogenesis, immunocytochemistry, gemmae, tip growth, vegetative reproduction     

光照强度对水蕨孢子萌发及配子体性别分化的影响

研究了不同光照强度条件对水蕨孢子萌发以及配子体性别分化的影响。结果表明:2 000~4 000 lx的光照强度条件有利于水蕨孢子萌发,4 000 lx光照条件下孢子萌发最快。光照强度约为4 000 lx时最有利于使水蕨发育为两性配子体。光照强度约为1 000 lx时最有利于使水蕨发育为雄性配子体。为水蕨的人工栽培和分子生物学研究提供理论依据。