欧报春二型花柱的繁育特性研究

二型花柱植物通常具有自交不亲和性,在不同植物中所表现的可育性不同。欧报春(Primula vulgaris)是典型的二型花柱植物,为了探究欧报春的繁育特性,通过温室栽培,对欧报春的长花柱和短花柱的花部特征、花粉和花柱形态、花粉活力、柱头可授性、花粉/胚珠比、杂交指数、杂交亲和性、花粉管观察进行研究。结果表明,(1)长花柱和短花柱的花冠直径、花冠筒长度、柱头高度、花药高度和花筒中部直径均表现出两型性;(2)花粉和柱头观察发现花粉极轴长、花粉赤道轴长、花柱直径、柱头乳突细胞和花粉数量均有差异;(3)长花柱的花粉/胚珠比为384.20,短花柱为369.70,属于兼性异交类型;长花柱和短花柱的花粉活力和柱头可授性能在较长时间内维持较高活力;(4)长花柱杂交指数值为5,短花柱为4,表明繁育系统类型为异交,部分自交亲和,需要传粉者;6种授粉组合均能结实,异型花间授粉的结实数明显高于同型自花授粉和异株同型授粉;短花柱为母本的异型花间授粉组合亲和性优于其他组合;欧报春存在自交不亲和性,长花柱的自交不亲和性低于短花柱。     

皖南奇葩—安徽羽叶报春

报春花科植物安徽羽叶报春(Primula merrilliana)是安徽特有种。1910年3月15日,我国 植物学界老前辈钟观光先生在皖南太平县(现改为黄山区)郭村乡首次采集到该种植物标本; 1924年由德国植物学家施莱谢尔(F.R.R.Schlechter)定名发表。山回路转,90年过去了,由于生存环境日益遭到破坏,安徽羽叶报春的分布范围越来越窄,种群数量日渐减少,现已被列为安徽省重点保护野生植物,并作为珍稀濒危物种被将要出版的《中国植物红皮书》第二卷收载。据调查,目前该种仅在黄山桃花峰,黄山区的谭家桥镇、郭村乡、贤村乡,石台县六都乡,宁国市板桥…     

珍稀濒危植物安徽羽叶报春遗传多样性的RAPD分析

利用RAPD分子标记对安徽特有濒危物种安徽羽叶报春（Primula merrilliana）6个自然居群的134个个体的遗传多样性进行了研究。从100个随机引物中筛选出12个RAPD引物,扩增共得到158条带,其中129个多态性位点（PPL）。POPGENE分析显示安徽羽叶报春具有较丰富的遗传变异（PPL=81.65%,He=0.2515,Ho=0.3849）。Nei′s基因多样性指数计算的居群间遗传分化系数（GST=0.5511）与Shannon信息指数（54.48%）基本一致。生境的片段化和基因流障碍可能是导致居群间遗传分化显著的主要原因。针对安徽羽叶报春的居群遗传变异提出了相应的保护措施：保护好自然生境和现有的居群及个体;加强居群间的基因流动;在迁地保护过程中,在尽可能多的居群中采样,以提高栽培居群的遗传多样性。     

安徽特有植物安徽羽叶报春的繁殖生物学研究

本文分别从物候、繁育结构和传粉等方面研究了国家三级保护植物、安徽特有种--安徽羽叶报春(Primula merrilliana)的繁殖生物学特征。研究结果表明: (1) 安徽羽叶报春是典型的形态和功能意义上的花柱二型的二年生植物, 其始苗期为9月, 一直持续到第二年6月底或7月初死亡, 各居群长柱花植株比短柱花植株开花略早3–5 d; (2) 安徽羽叶报春的散孔型花粉显示其在报春花属中有重要的系统意义和进化意义。同时, 短柱花花粉量比长柱花少, 但其花粉直径是后者的1.78倍左右; (3) 长花柱的雌蕊长度是短花柱的1.64倍, 而且其柱头上的乳头状突起比短花柱上的长而稀; (4) 3个研究居群的P/O比都不相同, 我们发现花粉量比胚珠数量有更大的变异, 这可能与生境有关; (5) 安徽羽叶报春为异花授粉植物, 蓟马属(Thrips)昆虫为其重要的传粉者, 其同型花授粉可育性远比异型花授粉的高; (6) 其长、短柱型种子没有明显的形态差异, 多属不等边七面体, 少为其他多面体。据研究, 在小居群中两种花柱类型植株的比例失衡, 生境的破坏和伴生种的消失可能是导致安徽羽叶报春濒危的重要原因。     

安徽羽叶报春和毛茛叶报春的微形态特征

在扫描电子显微镜和光学显微镜下,观察了安徽羽叶报春(Primula merrilliana Schltr.)与毛茛叶报春(Primula cicutariifolia Pax)的种子、花粉形态及表面纹饰与叶表皮形态结构.结果表明:2种类的种子都呈不规则七面体或多面体,多具五边形纹饰;安徽羽叶报春的种皮雕纹浅,网眼具许多小的乳头状突起;毛茛叶报春的种皮雕纹明显,网眼粗糙,具许多大的乳头状突起.2种类花粉均为球形,具散孔(孔数达10个以上),具网状雕纹.2种类的叶表皮细胞呈凹凸镶嵌状不规则排列,而在中脉处呈长方形或略带微波状长方形,上表皮细胞稍大;叶两面被腺毛,且顶端具水孔.气孔的分布属于偏叶下表面生长,在边缘处尤密,而在中脉处近无;相对而言,安徽羽叶报春的气孔略比毛茛叶报春的气孔小,且密度也低;电子显微镜下2种类的气孔外拱盖内缘光滑,保卫细胞外缘隆起明显,中间凹陷,其上着生的乳头状突起安徽羽叶报春不如毛茛叶报春明显.     

珍稀濒危植物陕西羽叶报春的开花及传粉生物学研究

陕西羽叶报春为中国珍稀濒危植物,研究其开花物候、传粉者及访花行为、花粉活力、柱头可授性、繁育系统,以明确陕西羽叶报春的传粉特性及制濒机制。以勉县陕西羽叶报春野生居群为研究对象,通过野外观察和人工授粉实验首次对陕西羽叶报春的传粉生物学进行研究。结果表明:(1)陕西羽叶报春种群花期为2-4月中旬,单花花期一般为14~17 d;单花开花进程中花部形态有6个明显发育变化:全部被萼片包裹、花苞伸出并为深粉色、花朵打开为淡粉色、花冠为白色、花朵枯萎、花冠脱落花萼宿存。(2)陕西羽叶报春为异花授粉植物,蜜蜂属为其主要传粉者。(3)柱头在花粉未开裂前就具有可授性,可授性逐渐增强;花药在花瓣打开后的第3天才开始开裂、散粉,在第4天活力最高,为98.18%,此后逐渐减弱。(4)繁育系统检测显示,长、短柱型花的花粉/胚珠比分别为902.26和831.48,杂交指数为4;套袋实验显示,陕西羽叶报春异型交配可育,同型交配不可育。由此表明,陕西羽叶报春的繁育系统为异交型,自交不亲和,需要传粉者。综上所述,陕西羽叶报春传粉者种类少、自交不亲和、胚珠败育现象可能是导致陕西羽叶报春濒危的重要原因。     

安徽羽叶报春愈伤组织的诱导和培养

为了寻找大批量快速繁殖安徽羽叶报春(Primula merrilliana)的有效办法,笔者以其叶片、叶轴为外植体,用不同浓度生长调节物质进行愈伤组织诱导实验.结果表明:(1)愈伤组织诱导的最适培养基为:MS 2.0mg/L 6 BA 0.5mg/L～1.0mg/L 2,4-D,叶片、叶柄出愈率均达100%.(2)MS培养基加0.1mg/L 2,4～D和1.0mg/L～1.5mg/L TDZ对叶柄的诱导效果较佳,其诱导率达81%,而且在这种生长调节物质浓度下的愈伤组织可直接分化出不定芽.     

安徽羽叶报春核心和边缘居群的形态变异比较研究

为了解濒危二型花柱植物安徽羽叶报春(Primula merrilliana)居群的形态变异,对其4个核心居群和3个边缘居群的14个形态性状进行了比较研究。结果表明,核心居群形态性状的变异系数为0.09~0.50,边缘居群为0.05~0.56,变异幅度两者间差异不明显;核心居群有8个性状的均值显著高于边缘居群(P0.05),仅有3个性状(花冠直径、花瓣宽和叶宽)为边缘居群高于核心居群。核心居群两型花间的互惠指数较高也较稳定(0.83~0.90),花型间互惠程度较高,而边缘居群的互惠指数差异较大(0.60~0.93),不同居群的互惠程度变化较大。因此,两型花柱植物安徽羽叶报春的形态性状变异基本支持"中心丰富模型"假说,并对其保护策略进行了探讨。     

二型花柱植物金荞麦的繁殖生态学研究

通过野外实验观察和人工控制套袋等方法,从金养麦的花部基本特征、开花动态、花粉胚珠比(P/O)、花粉活力、柱头可授性、杂交指数、套袋实验及访花昆虫等方面对其繁殖生态学进行了研究.结果显示:(1)金荞麦在同一居群中同时具有长柱型(L-型)和短柱型(S-型)两种花型,短花柱花直径(7.25±0.11 mm)显著大于长花柱花直径(6.79±0.11 mm),长花柱花的柱头和花药高分别为3.39±0.04 mm和1.80±0.02 mm,短花柱花的柱头和花药高则分别为1.89±0.04 mm和3.19±0.06 rnm,表现出互补式雌雄异位的花部特征.(2)金荞麦8～10月开花,单花序的花期为15～23 d,单花的花期为1～3 d,开花进程中,内轮雄蕊先散粉,外轮雄蕊后散粉;S-型花的花粉活力高于L型花的花粉活力,但其单花花粉量低于L-型花,显示了两种花型的自我调控机制.(3)套袋实验表明,金荞麦自花自交不亲和,但具有型内和型间亲和性,L型和S-型花的P/O值分别为810±40.48和526.5±42.24,表明其繁育系统为兼性异交,需要传粉者,但L-型花更倾向异交.(4)金荞麦的主要访花昆虫为膜翅目(Hymenoptera)、双翅目(Diptera)、鳞翅目(Lepidoptera)、半翅目(Hemiptera)和蜻蜒目(Odonata) 19个科37种昆虫,其中,两种花型拥有12种共同的访花昆虫,L-型花访花昆虫14种,S-型花访花昆虫35种,表明S-型花对昆虫具有更强的吸引力.研究表明,金荞麦是典型的二型花柱植物,虽然具有严格的自交不亲和性,但显示一定的型内亲和性.     

安徽羽叶报春的有效传粉昆虫及花朵密度和种群大小对传粉效果的影响

对濒危植物有效传粉昆虫种类及其传粉行为的主要影响因素进行研究是科学合理地制订保护措施,从而对该物种实施有效保护的一个前提条件.安徽羽叶报春Primula merrilliana为二年生草本,具二型花,是我国特有的珍稀濒危物种.本文对其有效传粉昆虫种类、传粉行为及花朵密度和种群大小对传粉效果的影响进行了研究.结果表明安徽羽叶报春的有效传粉昆虫为截形蜂虻Bombylius major和中华雏蜂虻Anastoechus chinensis,而不是先前认为的蓟马Thrips sp,.花朵密度和种群大小对传粉效果均有显著的影响.高密度的花朵可以提高对有效传粉昆虫的吸引力,传粉昆虫数/天、被访花朵数/天和平均每花的被访次数/天与样方花朵的密度呈正相关关系.柱头所接受的正配花粉数和总花粉数及正配花粉数所占的比例均随种群中植株数目的增加而增加.型比的偏离和传粉昆虫的缺乏可能是导致小种群中传粉不利的主要因素.     

Genetic diversity within and among populations of the endangered and endemic species Primula merrilliana in China

Primula merrilliana Schltr. is an endangered and narrowly-distributed endemic species of southern Anhui Province in China. In this study, the level of genetic variation and the pattern of genetic structure in six natural populations of P. merrilliana were assessed by using ISSR (inter-simple sequence repeats) markers. Based on ten primers, 137 clear and reproducible DNA fragments were generated, of which 109 were polymorphic. The statistical results indicated that there was a relatively low genetic diversity within populations, and a high genetic differentiation among populations (G_ST = 0.53, Φ_ST = 0.49). The level of population genetic diversity was correlated to habitat type and the gene flow (N_m) was low with only 0.45. The unexpected genetic structure of P. merrilliana may be explained by limited gene flow that was caused by habitat fragmentation and limited seeds and pollen dispersal ability, self-compatible breeding system and biennial life form.     

Highly differentiated populations of the narrow endemic and endangered species Primula cicutariifolia in China,revealed by ISSR and SSR

The perennial herb Primula cicutariifolia Pax is an endangered and endemic species with narrow distribution in eastern Anhui and Zhejiang provinces of China. In this study, the levels of genetic variation and the pattern of genetic structure in five natural populations of P. cicutariifolia were assessed by inter-simple sequence repeats (ISSR) and simple sequence repeat (SSR) markers. Both markers revealed that there was remarkably low genetic variation within populations (e.g., H_e = 0.19 and 0.18, for ISSR and SSR respectively) and high differentiation among populations (G_ST = 0.714 and 0.611; Φ_ST = 0.698 and 0.599, for ISSR and SSR respectively). The level of population genetic diversity was correlated to population size only detected by ISSR markers. The genetic structure of P. cicutariifolia may be explained by limited gene flow that was caused by habitat fragmentation and limited seeds and pollen dispersal ability, self breeding system and biennial life form. To protect and avoid disappearance of P. cicutariifolia, much more attentions should be paid to protect all the remnant populations and their habitats, and three management units, i.e. Tianmushan, Damodao, and Panan units, were proposed.     

荒漠植物白刺属4个物种的生殖分配比较

选定乌兰布和沙漠地区白刺属4种植物为研究对象,通过对其样株在花期的各生殖构件的数量特征及生物量调查,系统研究了唐古特白刺(Nitraria tangutorum Bobr.)、西伯利亚白刺(Nitraria sibirica Pall.)、大白刺(Nitraria roborowskii Kom.)和泡泡刺(Nitraria sphaerocarpa Maxim.)4种白刺属植物在生殖枝水平上的生殖分配。结果表明:不同白刺属植物在分株高度、生殖枝长、生殖枝基径、单枝花数、花序干重、枝叶干重等生殖构件的数量性状方面均有显著差异,其中泡泡刺的各生殖构件的数量均最小;除了西伯利亚白刺的生殖分配值达到44.51%外,其余3种白刺的生殖分配值均没有超过20%。经统计分析,4种白刺种群的生殖枝长分别与分株高度呈显著(P<0.05)的直线性正相关关系;生殖枝花序干重与分株高显著正相关;4种白刺的生殖分配随着分株生殖枝生物量的增加而减少,即白刺的个体大小与生殖分配之间呈现负相关关系。这种生殖分配特点反映了不同白刺植物对生长环境的资源利用、与克隆繁殖的权衡及对生态适应的策略。     

濒危植物长叶榧的光合生理生态特性

利用Li-6400 XT便携式光合作用仪对林窗、林缘、林下3种生境中的长叶榧(Torreya ackii)在春、夏、秋、冬4个季节里的光合生理生态指标进行测定,探讨3种生境中长叶榧光合能力的季节变化及其对不同光环境的响应,分析其濒危机制,为长叶榧的迁地保护和种群的繁衍复壮提供理论依据。结果显示:(1)林窗、林缘的长叶榧净光合速率(Pn)日变化在夏季呈"双峰"曲线,其它3个季节均呈"单峰"曲线;林下的Pn日变化在4个季节均呈"单峰"曲线。(2)3种生境中最大净光合速率(Pnmax)、光饱和点(LSP)、表观量子效率(AQY)、最大羧化速率(Vcmax)、最大电子传递速率(Jmax)、磷酸丙糖利用率(TPU)均为夏季最高,使得夏季有较强的光合作用能力,但夏季林窗、林缘的长叶榧出现光合"午休"现象,光补偿点(LCP)、暗呼吸速率(Rd)也较高,使得夏季林窗生境的长叶榧日均Pn明显低于于秋季,林缘的日均Pn与秋季差异不显著。(3)4个季节的日均Pn、Pnmax、LSP、Vcmax、Jma、TPU均为林窗最高,林窗与林下差异显著,表明长叶榧具有阳性植物的特点,适宜生长在光照较强的林窗生境。(4)在生长旺盛的夏、秋季,长叶榧的LSP比伴生物种低,LCP比伴生物种高,对光适应的生态幅度较窄;与伴生物种相比,长叶榧的Pn较低,光合能力较弱,在激烈的种间竞争中处于不利地位,可能成为其濒危的一个重要原因。     

Systematics and evolution of the genus Torrubiella (Hypocreales, Ascomycota)

Torrubiella is a genus of arthropod-pathogenic fungi that primarily attacks spiders and scale insects. Based on the morphology of the perithecia, asci, and ascospores, it is classified in Clavicipitaceae s. lat. (Hypocreales), and is considered a close relative of Cordyceps s. 1., which was recently reclassified into three families (Clavicipitaceae s. str., Cordycipitaceae, Ophiocordycipitaceae) and four genera (Cordyceps s. str, Elaphocordyceps, Metacordyceps, and Ophiocordyceps). Torrubiella is distinguished morphologically from Cordyceps s. lat. mainly by the production of superficial perithecia and the absence of a well-developed stipitate stroma. To test and refine evolutionary hypotheses regarding the placement of Torrubiella and its relationship to Cordyceps s. lat., a multi-gene phylogeny was constructed by conducting ML and Bayesian analyses. The monophyly of Torrubiella was rejected by these analyses with species of the genus present in Clavicipitaceae, Cordycipitaceae, and Ophiocordycipitaceae, and often intermixed among species of Cordyceps s. lat. The morphological characters traditionally used to define the genus are, therefore, not phylogenetically informative, with the stipitate stromata being gained and/or lost several times among clavicipitaceous fungi. Two new genera (Conoideocrella, Orbiocrella) are proposed to accommodate two separate lineages of torrubielloid fungi in the Clavicipitaceae s. str. In addition, one species is reclassified in Cordyceps s. str. and three are reclassified in Ophiocordyceps. The phylogenetic importance of anamorphic genera, host affiliation, and stipitate stromata is discussed.     

Study on reproduction ecology of endangered species Abies chensiensis

Qinling fir, Abies chensiensis, is endemic to China and has been listed in the China Plant Red Data Book as one of the second class conservation plants. It is found scattered only in the forested pockets of the Qinling, Bashan, and Shennongjia Mountains with altitude from 1 300 m to 2200 m in Shaanxi, Gansu, Henan, Sichuan, and Hubei Provinces. To conserve and effectively restore this species and explore its processes of reproduction, the production characteristics of cone and seed yields, seed bank dynamics, and seed germination rates of five Abies chensiensis populations (A, B, C, D, and E, respectively, in the Abies chensiensis-Pinus tabulaeformis-Sinarundinaria nitida-Carex lanceolata association, Abies chensiensis-Quercus aliena var. acutserrata-Litsea pungens-Carex lanceolata association, Abies chensiensis-Betula albo-sinensis-Sinarundinaria nitida-Duchesnea indica association, Abies chensiensis-Indigofera amblyantha-Carex lanceolata association and Abies chensiensis-Pinus tabulaeformis-Smilax stans-Carex lanceolata association) were studied in their natural habitats across 18 plots in the Qinling Mountain area. Experiments were carried out in laboratory and field conditions. The results showed that all the five populations had the potential to produce seeds, and higher yields occurred in the lower and middle altitude areas every three to five years. The majority of cones appeared on the upper and middle crown and the west, south, and east faces of the crown, and the majority of full seed appeared on the middle portion of the cone. The weight per 1000 seeds was 43.2 g, in which 44.8% had growing potential. The germination rate of seeds in the natural forest was 6.1% and the proportion of seeds lost or destroyed in different populations in the natural forest was 93.9%. The germination rate of seeds planted in the nursery was higher than that in the natural forest, and the germination rate in the lower or middle altitude populations was higher than that in the upper altitude populations. The course from seed to seedling was the critical period in the life cycle of A. chensiensis populations under natural conditions. Reproduction courses were influenced positively by an abundant coverage of tree layer, organic material in the soil, thick soil, and a dense population of parent trees, whereas they were influenced negatively by human disturbance and light. In situ conservation of A. chensiensis should be carried out in the future so as to promote expansion of the population. Thinning the shrub layer and grass layer will also help seeds to penetrate the soil, promoting seed germination. The artificial population should be expanded by collecting seeds in the harvest years. Fast-growing and high-yield plantations should be developed on cloudy slopes at lower or middle altitudes.     

Uniformity of organellar DNA in Aldrovanda vesiculosa, an endangered aquatic carnivorous species, distributed across four continents

Organellar DNA from the widely distributed but rare and critically endangered aquatic carnivorous plant Aldrovanda vesiculosa (Droseraceae) was examined. Six chloroplast intergenic regions (3700 nt in total) were sequenced before analyzing the Southern-RFLP (Restriction Fragment Length Polymorphism) of 2 mt gene flanking regions. Only two different chloroplast haplotypes among 15 A. vesiculosa accessions from Africa, Australia, Europe, and Japan were found, generally distinguishing European and non-European plants, with two exceptions. Genetic variation observed in A. vesiculosa appears to be even lower than in other aquatic species with a similar world-wide distribution. A recent bottleneck followed by long-distance dispersal by water birds or low mutation rates could be responsible for the observed genetic uniformity. Estimation of genetic distances based on six chloroplast intergenic regions led to the conclusion that the chloroplast genome of A. vesiculosa matches more closely to that of Drosera regia than Dionaea muscipula, a sister genus sharing snapping traps. The inconsistency between genetic distance estimates based on nuclear and cytoplasmic markers may reflect a chloroplast capture. In A. vesiculosa, a four amino acids substitution (TGWS) in the amino acid sequence of ATP synthase alpha subunit (ATP1), highly conserved mitochondrial protein, was discovered, unique among all organisms based on current knowledge.