2种培养基下紫萁配子体发育及孢子体形成的研究

采用光镜技术对不同培养基下紫萁配子体发育和孢子体形成进行了研究.结果表明:(1)紫萁孢子绿色,四面体形,具三裂缝,孢子两极萌发分别产生假根和原叶体细胞,原叶体细胞形成球形体,球形体产生分生细胞发育为片状体和原叶体.(2)原叶体可为雄性、雌性或两性;雄原叶体较小,其两翼基部产生多数精子器;雌原叶体大,具有明显的中肋,在中...     

蕨类植物孢子与种子植物花粉萌发的比较

蕨类植物孢子与种子植物花粉在有性生殖过程中都具有重要的作用。花粉作为种子植物的雄配子体,通过萌发后极性生长的花粉管将精细胞送到胚囊完成受精作用。蕨类植物孢子作为配子体的原始细胞,通过不对称的有丝分裂产生一大一小两个细胞,小细胞萌发出极性生长的假根,大细胞继续分裂发育为原叶体（配子体）。成熟的花粉和蕨类植物孢子都是代谢高度静止的细胞,两者的萌发过程不仅都受到各种不同环境因子的影响,而且在信号转导、极性建立和能量代谢等方面可能有着相似的调控机制。本文综述了蕨类植物孢子和种子植物花粉萌发过程的差异和保守性特征。     

蕨类植物孢子与种子植物花粉萌发的比较

蕨类植物孢子与种子植物花粉在有性生殖过程中都具有重要的作用。花粉作为种子植物的雄配子体, 通过萌发后极性生长的花粉管将精细胞送到胚囊完成受精作用。蕨类植物孢子作为配子体的原始细胞, 通过不对称的有丝分裂产生一大一小两个细胞, 小细胞萌发出极性生长的假根, 大细胞继续分裂发育为原叶体(配子体)。成熟的花粉和蕨类植物孢子都是代谢高度静止的细胞, 两者的萌发过程不仅都受到各种不同环境因子的影响, 而且在信号转导、极性建立和能量代谢等方面可能有着相似的调控机制。本文综述了蕨类植物孢子和种子植物花粉萌发过程的差异和保守性特征。     

骨碎补科两种植物配子体发育的研究

首次报道了骨碎补科(Davalliaceae)的大叶骨碎补(Davallia formosana Hayata)和阴石蕨[Humata repens (L.f.) Diels]配子体发育过程.两者孢子均为单裂缝,椭圆形,不具周壁,书带蕨型(Vittaria-type)萌发;成熟原叶体心形,边缘及背腹面均分布有毛状体;精子器和颈卵器类型为同型孢子薄囊蕨类所具有的一般类型.总结了大叶骨碎补(D.formosana Hayata)和阴石蕨[H.repens (L.f.) Diels]的配子体发育在孢子大小、原叶体边缘细胞形状、精子器和颈卵器形态及毛状体产生时间等方面的异同,初步讨论了这两个种配子体的抗逆性、营养繁殖、假根功能及其可能的系统学意义.     

肿足蕨的配子体发育研究

对肿足蕨(Hypodematium crenatum(Forssk.)Kuhn)的孢子进行人工培养,在显微镜下观察其孢子萌发和配子体发育.结果表明,肿足蕨的孢子深褐色,二面体型,单裂缝,具周壁,有密集的褶皱状纹饰.孢子赤道面观为肾形,极面观为椭圆形.孢子萌发类型为书带蕨型(Vittaria-type),原叶体发育为叉蕨(Aspidium-type).成熟原叶体为对称心形,原叶体上毛状体极其发达,有两种不同类型的毛状体,分别为乳头状和长针状.假根分叉,常见膨大.成熟的原叶体为雌雄同株,精子器由3个细胞构成,同一原叶体上同时存在处于不同发育时期的精子器,颈卵器长且较为弯曲.肿足蕨的配子体发育表现出较为进化的特点,同时也形成了对石灰岩生境的高度适应机制.     

石灰岩地区蕨类植物低头贯众的配子体发育研究

采用原生境腐殖土对低头贯众[Cyrtomium nephrolepioides (Christ) Cop.]孢子进行培养,在显微镜下详细观察了其配子体发育的全过程.结果表明:低头贯众孢子深棕褐色,二面体形,极面观椭圆形,孢子萌发不具假根或为书带蕨型(Vittaria-type);丝状体由3～8个细胞构成;片状体上偏斜具毛状体,宽达10个细胞;原叶体的发育为叉蕨型(Asplenium-type).成熟的原叶体为对称心形,具乳头状毛状体,假根分叉,根尖膨大,精子器壁由3细胞构成和颈卵器弯曲等表现出进化的特征,但假根含有叶绿体又表现了原始的系统学特征.研究认为孢子萌发较慢,假根尖膨大和毛状体等似乎是该种配子体对石灰岩土壤特殊生境的适应对策.     

蕨类植物孢子萌发及原叶体发育的观察

以腐叶土为培养基质,对21种蕨类植物进行了孢子萌发和原叶体发育的研究,结果表明：①不同时期播种的同种蕨类的孢子,发育出原叶体和幼孢子体所历经的时间长短不同;②孢子萌发和配子体生长发育的适宜温度约为15～24℃;⑨稀有蕨类的孢子萌发率低,而在野外能形成较大种群的蕨类的孢子萌发率高;④用GA3处理孢子可以促进萌发;⑤当原叶体上长出幼孢子体时,原叶体由大变小,由绿变黄,21种蕨类的原叶体都在幼孢子体上长出第3片叶时消失;⑥幼孢子体上长出的第1、2片叶在形态上与以后长出的叶不同;⑦孢子萌发需要光;⑧1片原叶体尽管有多个颈卵器,但仅发育出1株幼孢子体;⑨利用腐叶土进行蕨类孢子繁殖是一种经济实用的繁殖方法。     

粗齿黔蕨配子体发育的研究

用原生境腐殖土对粗齿黔蕨(Phanerophlebiopsis blinii(Lévl.)Ching)的孢子进行培养,显微镜下观察孢子萌发和配子体发育过程.结果表明:粗齿黔蕨的孢子深棕色,单裂缝,极面观椭圆形,赤道面观为半圆形.播种1周后孢子萌发,萌发类型为书带蕨型(Vittaria-type),配子体发育为叉蕨型(Aspidium-type).丝状体由4～12个细胞组成,片状体宽达9个细胞,斜向一侧生长,边缘具毛状体.播种约2个月后形成原叶体,成熟原叶体成对称心形.在粗齿黔蕨的配子体发育过程中,成熟原叶体的背腹面和边缘均被毛状体,假根有分叉且尖部常膨大,并含有较大的颗粒状贮藏物,精子器有3个壁细胞等特征较为进化,而颈卵器粗短且直立的特征较为原始.粗齿黔蕨的精子器和颈卵器发育不同步,精子器的出现和成熟均早于颈卵器的发育.从配子体发育的角度,初步探讨了粗齿黔蕨野外种群数量较少的成因.     

人参(Panax ginseng)根系分泌物成分对人参致病菌的化感效应

采用室内培养结合生物学测定的试验方法,研究了不同浓度人参(Panax ginseng)根系分泌物成分苯甲酸、邻苯二甲酸二异丁酯、十六酸和2,2-二(4-羟苯基)丙烷对人参立枯丝核菌(Rhizoctonia solani)、黑斑菌(Alternaria panax)、疫病菌(Phytophthora cactorum)、菌核菌(Sclerotinia schinseng)、锈腐菌(Cylindrocarpon destructans)和绿色木霉菌(Trichoderma viride)菌落生长及孢子萌发的化感效应.结果显示,不同浓度人参根系分泌物成分对人参致病菌及绿色木霉菌的化感效应存在显著差异.苯甲酸浓度与人参立枯丝核菌、菌核菌和锈腐菌菌落生长以及人参黑斑菌、锈腐菌孢子萌发呈负相关,与人参黑斑菌、绿色木霉菌菌落生长呈正相关;对人参疫病菌菌落生长的化感效应表现为低浓度和高浓度抑制,中浓度促进.邻苯二甲酸二异丁酯浓度与人参立枯丝核菌、黑斑菌、菌核菌和绿色木霉菌菌落生长以及人参黑斑菌孢子萌发呈负相关;对人参锈腐菌菌落生长和孢子萌发表现为低浓度和高浓度抑制,中浓度促进;对人参疫病菌菌落生长表现为低浓度和中浓度抑制,高浓度促进.2,2-二(4-羟苯基)丙烷浓度与人参立枯丝核菌、黑斑菌、疫病菌、绿色木霉菌菌落生长以及人参黑斑菌、锈腐菌孢子萌发呈负相关;对人参菌核菌、锈腐菌菌落生长表现中浓度促进,高浓度抑制.十六酸浓度与人参锈腐菌、疫病菌和绿色木霉菌菌落生长呈正相关,与人参锈腐菌孢子萌发呈负相关,对黑斑菌孢子萌发表现为中浓度抑制.4种根系分泌物的等量混合物浓度与人参致病菌及拮抗木霉菌菌落生长速率呈负相关.     

龙津蕨的配子体发育特征及其系统学意义

采用改良Knop's营养液液体培养基于25℃恒温培养箱中培养龙津蕨(Mesopteris tonkinensis)的孢子,每天光照12 h,黑暗12 h,光照强度为2 500 lx。用光学显微镜观察记录其孢子萌发、配子体发育的全过程,为龙津蕨系统学的研究提供配子体发育方面的详实资料。结果表明:成熟孢子深褐色,不透明,两侧对称,极面观椭圆形,赤道面观圆角三角形,具单裂缝,孢子周壁具密集的脊状褶皱。播种后15 d左右萌发,形成2~5个细胞长的丝状体。孢子萌发类型为书带蕨型(vittaria-type)。具单细胞假根,不含叶绿体,基部膨大。20 d左右发育成片状体,30 d左右形成幼原叶体,幼原叶体不对称,成熟原叶体心脏形对称,56 d左右形成成熟原叶体,原叶体发育类型为铁线蕨型(adiantum-type)。幼原叶体仅左右两翼顶端细胞产生乳突毛状体,成熟原叶体边缘及背腹面都具少量乳突毛状体,毛状体由单细胞构成。68 d左右精子器开始出现,精子器近圆球形,由基细胞、环细胞、盖细胞构成。75 d左右颈卵器出现,成熟颈卵器颈部由3层细胞构成。其侧面观柱状,顶面观为铜面状。颈卵器垂直于原叶体表或向原叶体基部倾斜。另外,根据已知的金星蕨科其他属的配子体发育特征,发现龙津蕨配子体发育的这些特征与他们存在较大的区别,因此龙津蕨系统学位置还有待于进一步研究。     

球腺肿足蕨的配子体发育特征及其系统学意义

采用改良Knop’s营养液液体和固体培养基,对球腺肿足蕨的孢子进行人工培养,利用光学显微镜观察其孢子的萌发及配子体发育过程。结果表明:成熟的孢子深褐色,不透明,极面观为椭圆形,赤道面观为豆形,单裂缝,周壁具密集的波纹状褶皱。孢子萌发类型为书带蕨型,原叶体发育类型为三叉蕨型。孢子接种后7d左右萌发,30d左右形成为片状体,50d左右发育为幼原叶体,幼原叶体不对称,但成熟原叶体心脏形对称。原叶体边缘及背腹面都具乳头状毛状体。75d左右精子器出现,精子器近圆球形,由3个细胞构成。90d左右颈卵器出现,成熟颈卵器颈部由4～5列细胞构成,3～5层细胞高。原叶体受精后1个月内可看到幼孢子体生成。最后讨论其系统学意义。     

Jasmonic acid promotes division of fern protoplasts, elongation of rhizoids and early development of gametophytes

The effects of jasmonic acid (JA) on spore germination, early gametophyte development and sporophytic protoplast culture of the fern Platycerium bifurcalum (Cav.) C. Chr. were investigated. JA and no influence on spore germination and primary rhizoid initiation, but significantly promoted early gametophyte development, which was evident from the longer primary rhizoids as well as the higher number of rhizoids and cells per gametophyte. Jasmonic acid (1 μ M ) also promoted the transition of gametophytes from a filamentous to a planar growth. Optimal primary rhizoid elongation and highest cell division activities in the gametophytes were observed at 0.01–1 μ M JA, while the highest number of rhizoids on gametophytes was obtained at 0.1–1 μ M JA. Jasmonic acid (0.01 μ M ) also stimulated initial protoplast divisions. Except for the experiment in which the effect of JA on germination was tested. JA concentrations exceeding 1 μ M did not promote cell elongation or cell division but were instead inhibitory. On the basis of these findings, we propose that JA may be involved in early stages of P. bifurcatum development.     

In vivo micro X-ray analysis utilizing synchrotron radiation of the gametophytes of three arsenic accumulating ferns, Pteris vittata L., Pteris cretica L. and Athyrium yokoscense, in different growth stages

In vivo X-ray analysis utilizing synchrotron radiation was performed to investigate the distribution and oxidation state of arsenic in the gametophytes of two hyperaccumulators, Pteris vittata L. and Pteris cretica L., and an arsenic-accumulating fern, Athyrium yokoscense in the several growth stages from germination. The distribution of arsenic in P. vittata changed through the development of the plant tissues as follows. In two-week-old gametophyte, arsenic was mainly present along the rhizoid. In the one-month-old gametophyte with reproductive organs, arsenic was accumulating uniformly in the sheet of cells, except in the reproductive area. After fertilization, arsenic was observed in the aboveground part of the sporophyte structures. P. cretica and A. yokoscense showed different distributions, respectively. P. cretica showed an accumulation of arsenic in the reproductive area, in contrast to P. vittata, before fertilization, while arsenic was observed in the aboveground part of the sporophyte after fertilization. A. yokoscense showed an accumulation of arsenic along the rhizoids before fertilization, while it was present mainly along the roots of the sporophyte after fertilization. Reduced arsenic (As(iii)) was observed in all stages and in all tissues of P. vittata gametophytes. Further, a reduction of arsenic was commonly observed among the three ferns, although arsenic was bounded to sulfur in A. yokoscense. These findings may be related to their own reproductive process or to detoxification mechanism. They provide basic information for the understanding of arsenic hyperaccumulation in these ferns, leading to further application of these gametophyte systems.     

Effects of inorganic nitrogen sources on spore germination and gametophyte growth in Botrychium dissectum

Abstract. The effects of variations in nitrogen source upon spore germination and gametophyte growth of the eusporangiate fern Botrychium dissectum forma obliquum were investigated. Spore germination and early gametophyte growth were directly related to the oxidation level of the supplied nitrogen source. Nitrate and nitrite inhibited spore germination and at concentrations above 0.035 mol m^-3 prevented it entirely. Ammonium promoted germination well above the levels attained on media without nitrogen. Concentrations of ammonium greater than 0.035 mol m^-3 often resulted in germination above 90%. The growth of young gametophytes from spores was reduced on media without nitrogen or on media with high concentrations of nitrate. Ammonium stimulated the growth of both young and older gametophytes. However, older gametophytes were able to grow on media containing nitrate as the sole nitrogen source. We conclude that a reduced nitrogen source is necessary for spore germination and early growth of Botrychium gametophytes. This requirement has several ecological implications which may be related to the distribution of these ferns and the establishment of mycorrhizal associations.     

SPORE GERMINATION AND DEVELOPMENT OF THE YOUNG GAMETOPHYTE OF THE OSTRICH FERN (MATTEUCCIA STRUTHIOPTERIS)

Light is required for the germination of spores of Matteuccia struthiopteris. Histochemical studies show that dormant spores contain no starch, but have an abundance of storage protein granules. Starch accumulates in the numerous chloroplasts of the spore on exposure to light and becomes gradually more extensive. Protein granules disappear as germination progresses. Following this, the centrally located nucleus migrates toward the proximal spore face. Concomitant with the nuclear migration, an increase of cytoplasmic RNA surrounding the nucleus occurs. An equal nuclear division and unequal cell division give rise to a 2-celled gametophyte consisting of a large prothallial cell and smaller rhizoidal cell. A new peripheral wall forms around the entire protoplast at the time of nuclear migration, while a transverse wall forms after nuclear division. The rhizoid emerges through the split raphe along the proximal spore face; it is rich in cytoplasmic RNA but contains very few chloroplasts and little starch. Electron microscopy of the 2-celled stage revealed a greater concentration of mitochondria, Golgi bodies, and a more extensive endoplasmic reticulum in the rhizoid than was found in the prothallial cell, which, however, was far richer in chloroplasts and lipid bodies. As the rhizoid elongates and becomes more vacuolated, cytoplasmic RNA decreases as cytoplasmic protein increases. The rhizoid undergoes no cell divisions, while the prothallial cell retains the potential for further cell division. The possible significance of the distribution of storage products, cell organelles, and other cell components were considered in relation to the non-equational cell division and differentiation of the 2 cells.     

重金属铅对3种蕨类植物孢子萌发和配子体发育的影响

研究了重金属铅对水蕨、中华桫椤和扇蕨孢子萌发及其对水蕨配子体发育的影响。结果表明：随着铅浓度的增加,水蕨、中华桫椤和扇蕨孢子的萌发率逐渐降低;在低于10^-4 mol·L^-1的环境中,水蕨孢子可以正常萌发;在低于10^-5 mol·L^-1的环境中,中华桫椤和扇蕨孢子能正常萌发;水蕨、中华桫椤和扇蕨的孢子都对铅具有一定的耐受性;铅对水蕨配子体的发育存在一定影响,铅使水蕨配子体呈不规则的心脏形,多发育为雄配子体;精子器凹陷入原叶体边缘;配子体细胞中叶绿体分布不均匀。本研究为铅污染土壤的植物修复筛选后备植物。     

Spore Germination of Ceratopteris thalictroides (L.) Brongn

Germination of the spores of Ceratopteris thalictroides wasexamined by light and scanning electron microscopy. Spores germinateby scission of the spore coat at the trilete markings. The initialcell divisions produce a proximal prothallial initial with rhizoidsthat are distal and lateral. This represents a reverse orientationof the more common situation in ferns. Evidence is presentedthat rhizoid initials divide with the most lateral of the daughtercells differentiating into a rhizoid. Rhizoids are long andunbranched. The uniseriate protonema is transient with bi-dimensionalgrowth established quite early. About a week following germination,the gametophyte is broad at the basal region and narrow at theanterior region. Further growth of cells in the basal regionis by elongation and the anterior region broadens to producean elongate-ovate gametophyte.