半夏珠芽发育过程的形态学和解剖学研究

通过形态学观察和石蜡切片方法研究了半夏[Pinellia ternata(Thunb.)Breit.]的珠芽发育过程,结果显示:半夏珠芽着生于叶柄的下部,起始于幼嫩叶柄的腹面最外轮维管束外周薄壁细胞;恢复分裂的薄壁细胞分裂形成珠芽原基细胞团,在原基生长突破叶柄表皮后分化形成具有生长点的珠芽结构,发育中的珠芽无根分化;珠芽的生长被动地终止于叶片衰老(倒苗),无明显的成熟发育过程。研究表明,半夏的珠芽是不定芽性质的无性繁殖结构,但在发育过程上明显区别于其它植物的珠芽发育。     

弥勒魔芋珠芽发育过程的形态学和解剖学研究

珠芽是弥勒魔芋的一种重要营养繁殖器官。以弥勒魔芋为材料,通过形态学观察以及解剖学研究,揭示了弥勒魔芋珠芽形成过程中的一系列特征。结果显示:弥勒魔芋珠芽生长于植株叶柄分叉以及裂叶分叉处,由主干茎或主干叶柄表皮下的薄壁细胞重新获得分裂能力后分化而来。珠芽的发育过程可分为珠芽原基启动形成期,珠芽膨大期和珠芽成熟期。珠芽的生长终止于植株衰老倒伏。研究表明,弥勒魔芋的珠芽生长位点明显区别于其他常见植物,珠芽繁殖是魔芋适应生态环境的一种重要机制。     

淡黄花百合珠芽发育过程的形态学与解剖学研究

以野生淡黄花百合(Lilium sulphureum)为实验材料,通过形态学观察、石蜡切片方法对珠芽的发生规律、发育过程中的形态学变化及解剖结构特征进行了研究,以阐明淡黄花百合珠芽繁殖的生物学机制。结果显示:淡黄花百合的珠芽形成于地上茎叶腋处叶柄的近基部位置,由叶柄表皮以内数层薄壁细胞不断分裂和分化形成;珠芽的发育过程可划分为启动期、膨大期和成熟期三个时期。成熟珠芽外观上成圆形或椭圆形,珠芽中部的薄壁细胞含有大量淀粉颗粒。淡黄花百合的珠芽具有很高的萌发率(90%以上)。研究表明,珠芽营养繁殖是其生态适应的一种重要机制。     

半夏胚胎发育的研究

半夏的大小孢子发育均属正常类型。只是种子成熟时没有胚的分化,而是形成一个原球茎。生长点的分化过程类似于珠芽的形成。种子发芽时原球茎突出种皮,在生长点下面的细胞,经过分裂,形成一个膨大的结构。根、叶原基的分化是在发芽过程中逐步完成的。     

单芽狗脊营养器官的解剖学研究

采用离析法和石蜡切片法对单芽狗脊营养器官进行形态解剖研究。结果表明：单芽狗脊叶为异面叶,上、下表皮细胞均为不规则型,仅下表皮有气孔器分布;叶柄维管束有2~6个,自叶柄基部向上至叶轴仅有2个较大的维管束;根状茎薄壁细胞之间有多个维管束散生分布,且富含丰富的淀粉粒;皮层在根的横切结构中占比较大,木质部的发育方式为外始式;单芽狗脊珠芽的发育过程分为三个阶段,珠芽原基的形成期、珠芽原基的分化期、成熟期。     

稀子蕨胞芽发育及营养器官的形态与解剖学研究

该研究采用形态观察法、石蜡切片法以及扫描电子显微镜法对稀子蕨(Monachosorum henryi)胞芽发育过程及营养器官进行观察分析,以揭示不同蕨类植物胞芽生殖在发育生物学上的异同,为进一步探讨蕨类植物胞芽发育与被子植物珠芽发育的异同等奠定基础。结果表明：(1)稀子蕨羽叶薄,由7~8层细胞组成,气孔分布于下表皮,无明显栅栏组织和海绵组织分化。(2)稀子蕨的叶轴含1束“心”形维管束,叶柄基部至中部含2束维管束;成熟根能看到明显的维管束组织,无髓。(3)稀子蕨的复羽叶发育过程可分为萌动期、卷拳期、展叶期、成熟期和衰老期;复羽叶上的胞芽发育从展叶期开始,包括胞芽原基发育期、胞芽分化期、胞芽膨大期和胞芽成熟期。(4)稀子蕨胞芽原基起源于叶轴与羽叶分叉处表皮细胞下的薄壁细胞层;胞芽原基分化出多个叶原基,整体呈指状“锚”状;胞芽成熟后掉落土壤或在母体上萌发生长出新叶。     

大蒜气生鳞茎形态发生及其碳水化合物和内源激素含量以及相关基因表达的变化特征

以大蒜品种‘二水早’(早熟)、‘麻江红蒜’(中晚熟)和‘徐州白’(晚熟)为材料,采用石蜡切片技术结合显微观察探讨气生鳞茎形成过程中植株茎尖和花序轴形态变化,并测定了‘麻江红蒜’气生鳞茎形成过程中可溶性糖、蔗糖、淀粉和内源激素含量及相关基因表达变化,明确不同熟期各品种大蒜气生鳞茎形成进程和形态解剖学特征,以及碳水化合物和内源激素与大蒜气生鳞茎形成的关系,以探讨大蒜气生鳞茎分化的生理机制。结果表明:(1)依据茎尖生长点和花序轴的形态解剖特征,将气生鳞茎形成进程划分为启动期、气生鳞茎原基分化期(包括保护叶原基、贮藏叶原基分化)、气生鳞茎膨大期和气生鳞茎成熟期等4个时期;3个品种气生鳞茎在相同发育时期的形态解剖学特征相同,但分化时间不同,其分化顺序与大蒜品种成熟期表现一致;当总苞叶叶尖露出叶鞘,花器官原基分化时,花序轴周围分生组织区域产生小突起,标志着气生鳞茎原基分化的开始;外层保护叶由白色转为紫色时气生鳞茎进入成熟期。(2)气生鳞茎开始膨大后,其可溶性糖和蔗糖含量均显著降低,淀粉含量显著升高;ZR含量在启动期显著升高;IAA和MeJA含量在气生鳞茎原基分化期维持在较高水平,但IAA含量随着气生鳞茎膨大显著降低,并在成熟期降至最低。(3)果聚糖代谢相关基因1-SST、1-FEH分别在膨大初期、膨大中期表达量显著升高;细胞壁转移酶基因CWI相对表达量在气生鳞茎原基分化期显著升高;蔗糖信号转导基因T6P和生长素信号转导的关键转录因子ARF1相对表达量均在气生鳞茎分化期显著升高;茉莉酸信号调控途径中的负调控因子JAZ相对表达量在大蒜气生鳞茎原基分化期和膨大初期均维持一个较低水平。研究认为,大量可溶性糖及ZR在茎尖积累,可以启动气生鳞茎原基分化,促进气生鳞茎形态发生;高浓度IAA和MeJA可促进气生鳞茎原基分化;气生鳞茎膨大消耗可溶性糖,且低浓度IAA有利于气生鳞茎膨大;成熟的气生鳞茎积累大量淀粉。     

东方百合鳞片繁殖小鳞茎发生的形态学观察

采用解剖学方法研究东方百合鳞片扦插繁殖中小鳞茎的组织发生过程。结果表明:小鳞茎的形态发生起源于鳞片近轴面基部的几层薄壁细胞,细胞脱分化后形成分生组织,再经过器官发生途径形成小鳞茎,属于外起源。小鳞茎发生过程可分为未分化期、启动期、生长锥形成期、小鳞片原基和根原基形成期、小鳞茎形成期。     

八角莲组织培养的器官发生途径研究

为探究小檗科植物八角莲组织培养的器官发生方式,该研究以八角莲离体叶片、叶柄在MS培养基上诱导产生的愈伤组织、不定芽、不定根为对象,用连续石蜡切片技术分析八角莲组织培养的器官发生途径。结果表明:八角莲愈伤组织形成的解剖学特征是靠近表皮的薄壁细胞经激素刺激恢复分裂能力,继续培养形成拟分生组织。拟分生组织可形成许多分化中心。通过对八角莲组织培养产生的不定芽细胞组织学观察发现芽原基起源于愈伤组织外侧的几层薄壁细胞,芽原基背离愈伤组织中央生长形成不定芽,故八角莲脱分化形成的芽起源方式为外起源。而八角莲的根原基起源于组织深处髓部薄壁细胞和部分维管形成层细胞,进而形成类似球形或楔形并朝韧皮部突起的根原基轮廓,根原基继续发育会突破表皮生成不定根,起源方式为内起源。八角莲离体再生途径为器官发生型,在组培苗生长过程中先诱导形成不定芽,再诱导形成不定根,在愈伤组织上形成维管组织将不定芽和不定根连接成完整植株。     

兰州百合组培鳞茎发育研究

该研究以兰州百合商品种球鳞片为外植体材料,通过组织培养诱导丛生芽萌发及高频增殖,再以丛生芽为材料诱导其发育形成小鳞茎,调节培养基对小鳞茎进行膨大发育培养,最终形成促进兰州百合组培鳞茎膨大发育的“三步”组培培养技术路线;对发育过程中形成的丛生芽、小鳞茎及膨大鳞茎进行淀粉含量测定与生长特征参数统计,分析各步培养对鳞茎形成发育过程中淀粉含量与形态变化的影响。结果表明：所建立的“三步”培养方案培育出的组培鳞茎直径、重量与鳞片数分别为1.66 cm、2.48 g和26.33片,有效地促进了鳞茎的膨大,并能诱导鳞茎主茎杆的形成发育;在培养进程中其淀粉含量呈现逐步增加的趋势,这表明与鳞茎膨大发育正相关,同时鳞茎大小、重量及鳞片数三者也表现为正相关性;当鳞茎所含鳞片数在26片以上时,其生长点易发育形成主茎杆。该文研究了兰州百合组培鳞茎的形成与膨大发育技术,所研发的“三步”培养组成的鳞茎膨大发育组培技术有效地促进了鳞茎的膨大发育,而膨大发育的鳞茎能有效地缩短田间生长周期,从时间上提高百合生产量,同时为实现兰州百合膨大的鳞茎种球规模化生产提供技术支撑。     

Morphology and molecular phylogeny ofTretopileus sphaerophorus, a synnematous hyphomycete with basidiomycetous affinities

Tretopileus sphaerophorus, a synnematous hyphomycete with basidiomycetous affinities was newly isolated from the decaying petiole and peduncle ofCocos nucifera collected in Depok, Indonesia. The species produced first a bulbil as a propagule on the top of a synnema. After the bulbil had fallen, the synnema proliferated about seven times to produce new bulbils, each time making conspicuous nodes at the upper part. By careful morphological observation, clamp connections were confirmed on the hyphae in the specimens and culture. In culture, each hyphal cell with or without a clamp was found to be dikaryotic by DAPI nuclear staining. Germination of the bulbils occurred first from projecting hyphal tips on their upper surface, which have been treated as germ pores. The inner structure of the bulbils, the hyaline mucus of the bulbils, and conidium-like hyphal fragments were also examined. Phylogenetically,T. sphaerophorus was inferred to be related to the Aphyllophorales based on the nuclear encoded small subunit (18S) rDNA using the homology search system (FASTA) and the neighbour-joining method. Part 10 in a series on the taxonomy of synnematous fungi.     

Effect of alar and CCC on induction and germination of bulbils in <Emphasis Type="Italic">Curculigo orchioides</Emphasis> grown in shake flask cultures

Bulbil formation in Curculigo orchioides is followed by asynchronous germination. The effect of alar and CCC incorporated in Murashige and Skoog (MS) medium has been studied on bulbil induction from leaf explants and subsequent germination of bulbils. MS medium contained 1 mg/l BA and 0.1 mg/l morphactin for bulbil induction while germination medium contained 1 mg/l gibberrelic acid and both the media contained alar or CCC (0.5–5.0 mg/l). Growth retardants markedly reduces the bulbil formation, yield and fresh weight of bulbils. Incorporation of retardants resulted in 60% germination inhibition, thereby prolonging the storage conditions.     

Rapid clonal propagation of Pinellia ternata by tissue culture

Adventitious buds or protocorm-like bodies were regenerated directly from excised explants without intervening callus. Differences in the ability of regeneration were observed among different plant organs with bulbils showing the highest regenerative ability followed by leaf blade and petiole. Ability of vegetative propagation of bulbil could be maintained by alternate solid-and liquid-medium culture. Theoretically, 1.7×10²⁷ plantlets could be produced from a single bulbil by this technique within one year based on the production and rapid growth of protocorm-like bodies and adventitious buds. Concentration of MS salts, NAA and sucrose influenced not only root formation from the differentiated adventitious buds, but also root number and length. For root formation, the best combination was one-half strength MS salts with 3–5% sucrose and 1 mg/l NAA. The high survival rate of 96% was recorded when plantlets were transplanted into a mixture of vermiculite:loam soil:peat moss (1:2:1). Plants from in vitro culture were morphological similar to field-grown plants. The acute toxicity of crude extracts from protocorm-like bodies was about one-fourth that of extracts from tubers of field-grown plants when tested with white mice. Tissue culture has potential for clonal propagation of Pinellia ternata plants for commercial use.Abbreviations MS Murashige and Skoog (1962) - 2,4-D 2,4-dichlorophenoxyacetic acid - NAA -naphthaleneacetic acid - BA 6-benzylaminopurine     

Effects of growth retardants on bulbil production by Narcissus twin-scales

Narcissus twin-scale propagules, cut from various positions in the parent bulb, were incubated with gibberellic acid (GA₃) or growth retardants. Bulbil production was inhibited in all cases by GA₃ at 10–100 mg/litre. Chlormequat chloride, chlorphonium chloride and paclobutrazol also inhibited bulbil production; in the case of paclobutrazol, outer twin-scales were more sensitive to lower concentrations of the retardant than inner ones. Ancymidol enhanced bulbil production (in numbers by up to 15%) in the outermost twin-scales, and had no stimulatory effect on the inner twin-scales. Treatments affected bulbil numbers and bulbil lengths about equally.     

Molecular cloning and characterization of a mannose-binding lectin gene from <Emphasis Type="Italic">Pinellia cordata</Emphasis>

Using RNA extracted from Pinellia cordata young leaves and primers designed according to the conserved regions of Araceae lectins, the full-length cDNA of Pinellia cordata agglutinin (PCL) was cloned by rapid amplification of cDNA ends (RACE). The full-length cDNA of pcl was 1,182 bp and contained a 768 bp open reading frame (ORF) encoding a lectin precursor of 256 amino acids. Through comparative analysis of pcl gene and its deduced amino acid sequence with those of other Araceae species, it was found that pcl encoded a precursor lectin with signal peptide. PCL is a mannose-binding lectin with three mannose-binding sites. Semi-quantitative RT-PCR analysis revealed that pcl is expressed in all tested tissues including leaf, stem and bulbil, but with the highest expression in bulbil. PCL protein was successfully expressed in Escherichia coli with the molecular weight expected.     

卷丹珠芽萌发的组织学观察

以卷丹(Lilium laneifolium)珠芽为试材,采用野外调查法、石蜡切片法、徒手切片法、离析法,观察珠芽各部分形态和结构,用分光光度法测定各片鳞叶的花青素和光合色素含量,为其珠芽繁殖生物学研究提供资料。结果表明,珠芽由鳞叶、鳞茎和不定根构成,鳞叶外表皮细胞具有发达的角质层,外表皮内侧1～2层叶肉细胞含有花青素;叶肉细胞含绿色造粉体,第1～3片鳞叶基部的绿色造粉体向不定根伸长方向集中分布,鳞叶色素含量由外至内逐渐降低;鳞叶维管束为外韧维管束。鳞茎主要由皮层和维管柱构成,鳞茎上端包括顶端分生组织和芽鞘,在下端细胞部分发生程序性死亡,但未发现类似叶片脱落时叶柄基部出现的离层结构。不定根起源于第2片鳞叶基部环生的鳞茎皮层细胞,不定根与周围鳞叶组织分离。在珠芽萌发过程中鳞叶的物质供给出现分化现象。