Classification of Chinese Wintersweet (Chimonanthus praecox) Cultivars Supported by Pollen Morphology

To classify the Chinese wintersweet(Chimonanthus praecox) cultivars and to study their evolution based on pollen morphology.Pollens of 12 representative wintersweet cultivars were examined by scanning electron microscopy(SEM).Q-cluster analysis was carried out based on the observation results.Results are as follows:(1) The pollen grains were 2lobed circular in polar view,elliptic in equatorial view.The pollen shapes were spheroidal or super-spheroidal by P/E(polar axis length/equatorial axis length) criteria.(2) According to pollen exine ornamentation,it was indicated that white wintersweet is most original.Yellow floral group could be classified into three subgroups:purple-hearted,halo-hearted and yellow-hearted type.Their evolutionary relationship was purple-hearted halo-hearted yellow-hearted.(3) Different wintersweet cultivars showed a different exine sculpture.Palynological analysis could be used in the classification of wintersweet cultivars.The result of cluster analysis indicated that the cultivars could be classified into three groups with a similarity coefficient of 0.41.Each group had similar pollen exine sculpture.It was found that the palynological classification coincided well with morphological classification.Our results support the suggestion that purple streaks or patches of inner-petals should be served as the first-order criteria in wintersweet classification.

Pollen morphology of Rhododendron subgen. Tsutsusi and its systematic implications

Eighty-four pollen samples were obtained for 80 taxa,of which,13 species and one variety are from sect.Brachycalyx Sweet,58 species and two varieties from sect.Tsutsusi Sweet,and six species from subgen.Pentanthera(G.Don) Pojarkova,respectively.Pollen morphology of all samples was observed using LM and SEM.Pollen grains are revealed to be spheroidal and tetrahedral with tricolporate apertures.Pollen sizes of sub-gen.Tsutsusi(Sweet) Pojarkova range from 37.67 μm to 61.06 μm,and the exine sculptures are more or less compactly granulated.Pollen sizes are significantly different between sect.Brachycalyx and sect.Tsutsusi of subgen.Tsutsusi.Rhododendron tashiroi Maxim.of sect.Tsusiopsis Sleumer shows a close affinity to sect.Brachycalyx.Pollen size and exine are consistent with general morphology in differentiating species in sect.Tsutsusi.Rhododendron huadingense B.Y.Ding & Y.Y.Fang,once placed as a member of sect.Brachycalyx,should be considered as a species in subgen.Pentanthera.

Pollen morphology in Saxifraga(Saxifragaceae) from Ny-Alesund, Svalbard, Arctic, and its taxonomic significance

Pollen morphology of eight species of Saxifraga,i.e.S.cespitosa,S.oppositifolia,S.cernua,S.nivalis,S.aizoides,S.rivularis,S.hieraciifolia,and S.hirculus,collected from Ny-Alesund,Svalbard,Arctic was examined using light and scanning electron microscopy.Pollen grains of Saxifraga species are subprolate or prolate,3-colpate,15.4–44.4μm in the polar axis,11.4–34.6μm in the equatorial axis,and show a P/E ratio 1.19–1.40.On the basis of exine ornamentation,four pollen types,viz.,the S.oppositifolia type(striate without scabrae on the muri),S.cernua type(striate with scabrae on the muri),S.nivalis type(microreticulate and operculum absent),and S.cespitosa type(microechinate and operculum present),were recognized.Hierarchical cluster analysis of the pollen morphological characters indicated that pollen morphology supports the infrageneric classification of the genus Saxifraga.

Pollen Morphology of Artemisia L. and Its Systematic Significance

The pollen of 57 species representing 7 sections of Artemisia was examined by light microscope and scanning microscope for the purpose to elucidate the systematic relationships of the genus. The examination indicates that the pollen grains present high concordance which is characterized by the globular or the approximate shape, 3\|lobed circular from polar view while granular or ellipse sphere from tropical plate with tricolporate structure. The exine of pollen has an obvious double structure of inner and outer layers (including the tectum and columnar layers) where the outer is thicker than the inner and the sculpture of exine degenerates into small spinules easily distinguishable from other genera of the Compositae. Based on exine sculpture, the pollen grains of Artemisia can be divided into two types: Myriantha type and Mongolica type, which possesses 4 subtypes according to the distribution forms of spinule: (1) Sacrorum subtype, (2) Oligocarpa subtype, (3) Lavandulaefolia subtype, (4) Anomale subtype.

Pollen morphology and trichome types of Betula spp. in the Hyrcanian forests of northern Iran

Pollen and trichome morphology of the genus Betula were evaluated from three main habitats in Iran using light and electron microscopy.Pollen types were identical and tri-porate;however,in terms of quantitative data,some differences were observed in exine(outside)wall thickness,length of polar axis and length of equatorial axis,possibly due to the environment.Pollen alone is insufficient to separate species of Iranian birch.Investigation of the trichome trait(small hairs or other outgrowths)revealed that birch species in Iran belong to:(1)Betula litwinowii Doluch.according to the low density of trichomes on the adaxial surface of the leaves and the lack of trichomes on the abaxial surface and many trichomes on the petioles;(2)Betula pendula Roth.due to the absence of trichomes on the adaxial surface and the low density of trichomes on the abaxial surface;and,(3)in the adaxial and abaxial surfaces of leaves and petioles,the trichomes had different types of pilose(long,soft hairs),and this strengthens the possibility of a different species or more likely a hybrid of B.pendula.

Pollen Morphology and Pollen Fertility Estimation of Three Medicinal Plant Species of <i>Hypericum</i>L. from Kaghan Valley, Northern Pakistan

Pollen morphology & pollen fertility estimation of three medicinal species belonging to genus Hypericum L. from flora of Kaghan valley, Northern Pakistan was investigated by light and scanning electron microscopy for the first time. The species are Hypericum elodeoides Choisy in, Hypericum oblongifolium Choisy, and Hypericum perforatum L. Pollen morphological characteristics with considerable variation are provided for these taxa. Among the studied taxa, the pollen grains were 3-4 colporate type and the largest pollen size was found in H. oblongifolium in polar view 23.0 μm and in equatorial view was 25.35 μm. The smallest pollen was of H. elodeoides in polar view which was 19.91 μm and in equatorial view was observed 12.53 μm in H. perforatum. The shape of the all pollen grain was circular to semi-angular in polar view, however in equatorial view the shape of the grains was oblate-spheroidal, in H. elodeoides, and H. oblongifolium while prolate in H. perforatum. Exine sculpturing was observed by scanning electron microscopy which showed foveolate sculpturing in H. elodeoides, reticulate in H. oblongifolium and scabrate in H. perforatum. Pollen fertility estimation ranged from 82.66% to 90.90% which shows that flora of selected species is well established.

Pollen Morphology of Tribes Gnaphalieae, Helenieae, Plucheeae and Senecioneae (Subfamily Asteroideae) of Compositae from Egypt

POLLEN morphology of twenty five species representing 12 genera of tribes Gnaphalieae, Helenieae, Plucheeae and Senecioneae (Asteroideae: Asteraceae) was investigated using light and scanning electron microscopy. The genera are Phagnalon, Filago, Gnaphalium, Helichrysum, Homognaphalium, Ifloga, Lasiopogon, Pseudognaphalium, Flaveria, Tagetes, Sphaeranthus and Senecio. Two pollen types were recognized viz. Senecio pollen type and Filago pollen type. Description of each type, a key to the investigated taxa as well as LM and SEM micrographs of pollen grains are provided.

Pollen morphology of the genus Cornukaempferia (Zingiberaceae) in Thailand

Cornukaempferia is a recently described genus of Zingiberaceae which only occurs in Thailand as a rare genus with limited geographical distribution.Only three species have been described so far,including a recently described new species,C.larsenii.These three species are morphologically very similar and additional data on other biological aspects are useful for the elucidation of their relationship.Pollen morphology of all three species of genus Cornukaempferia has been studied by light microscopy and scanning electron microscopy.The pollen grains are monad,spherical,inaperturate.The exine sculpture is echinate with psilate between the spines for C.aurantiflora and C.longipetiolata,or echinate with regulate between the spines for C.larsenii.This obser-vation helps support the taxonomic status of C.larsenii.

Pollen development and floral morphology of Populus pseudo-simonii

Pollen development and floral morphology of Populus pseudo-simonii were investigated by stain-squashing and anatomical techniques. It took approximately 16 days for the pollen to develop from pollen mother cells to mature pollen in the greenhouse. Meiosis of pollen mother cells was regularly applied and completed by a process of simultaneous cytokinesis. Pollen development was considerably asynchronous. The meiotic division was initiated at the bulgy middle position of the flower bud and proceeded towards the tip and base of the bud. The number and size of the nucleoli varied during pollen development and at most eight nucleoli formed in each daughter nucleus at the meiotic telophase,suggesting a paleopolyploid origin of the genus Populus. An association between floral morphology and pollen development was found and the ratio of width to length of flower buds or catkins presented an S-shaped curve related to pollen development as a function of time. The investigation on the pollen development and floral morphology of P. pseudo-simonii is important for further cross breeding programs of the section Tacamahaca.

Pollen morphology of selected tundra plants from the highArctic of Ny-lesund, Svalbard

Documenting morphological features of modern pollen is fundamental for the identification of fossil pollen, which willassist researchers to reconstruct the vegetation and climate of a particular geologic period. This paper presents the pollen morphol-ogy of 20 species of tundra plants from the high Arctic of Ny- lesund, Svalbard, using light and scanning electron microscopy.The plants used in this study belong to 12 families: Brassicaceae, Caryophyllaceae, Cyperaceae, Ericaceae, Juncaceae, Papav-eraceae, Poaceae, Polygonaceae, Ranunculaceae, Rosaceae, Salicaceae, and Scrophulariaceae. Pollen grain shapes included: spher-oidal, subprolate, and prolate. Variable apertural patterns ranged from 2-syncolpate, 3-colpate, 3-(-4)-colpate, 3-(-5)-colpate,3-colporate, 5-poroid, ulcerate, ulcus to pantoporate. Exine ornamentations comprised psilate, striate-perforate, reticulate, mi-croechinate, microechinate-perforate, scabrate, granulate, and granulate-perforate. This study provided a useful reference for com-parative studies of fossil pollen and for the reconstruction of paleovegetation and paleoclimate in Svalbard region of Arctic.

The morphological diversity of pollen in the genus Gossypium

Background Plant pollen has diverse morphological characteristics that can be consistently passed down from generation to generation.Information on pollen morphology is thus immensely important for plant classification and identification.In the genus Gossypium,however,in-depth research on pollen morphology is lacking,with only few reports on limited cotton species.To evaluate the diversity of pollen in Gossypium,we therefore conducted a comprehensive analysis of the pollen morphology of 33 cotton species and varieties using scanning electron microscopy.Results The 33 analyzed cotton samples exhibited common pollen morphological features,including spherical shapes,radial symmetry,echination,panporation,and operculation,while the pollen size,spine shape,spine density and length showed distinctive features.Pollen size varied significantly among species,with diameters ranging from62.43 μm in G.harknessii to 103.41 μm in G.barbadense.The exine had an echinate sculptural texture,and spines were mostly conical or sharply conical but occasionally rod-like.Spine density varied from 173 in G.incanum to 54 in G.gossypioides,while spine length ranged from 3.53 μm in G.herbaceum to 9.47 μm in G.barbadense.In addition,the 33cotton species and varieties were grouped at a genetic distance of 3.83 into three clusters.Cluster Ⅰ comprised five allotetraploid AD-genome cotton species,four D-genome species,and one K-genome species.Cluster Ⅱ included 13diploid species from A,B,D,E,and G genomes,whereas Cluster Ⅲ only consisted one E-genome species G.incanum.Conclusions Although pollen characteristics alone are not enough to resolve taxonomic and systematic relationships within the genus Gossypium,our results add to knowledge on palynomorphology and contribute to phenological information on these taxa.Our findings should aid future systematic and phylogenetic studies of the Gossypium genus.

14种酢浆草属植物花粉形态及其亲缘关系分析

利用扫描电镜对14种酢浆草属植物花粉形态及表面纹饰进行观测,对其花粉形态进行聚类分析,并基于孢粉学聚类结果,探讨其种间亲缘关系。结果表明:(1)所观测的14种植物花粉粒为近球形或扁球形,极面观均为三裂圆形,多数为3沟花粉粒,稀2沟(星星酢浆草)和4沟(黄花酢浆草);其中,96.3%花粉粒为中等大小,3.7%为小花粉粒;不同花柱类型都表现为长雄蕊花粉比短雄蕊花粉大;外壁纹饰可分为复网状和网状两类。(2)首次发现3种存在异常花粉粒,分别为桃之辉酢浆草、一片心酢浆草及黄花酢浆草,花粉的异常表现为萌发沟数目和排列异常,其外壁纹饰结构与正常花粉粒未有明显不同。(3)根据外壁纹饰可将14种划分为2大类。一类为复网状花粉,仅构巢酢浆草和果香酢浆草为该类纹饰,二者亲缘关系较近。另一类为网状花粉,对12种具网状花粉酢浆草进行聚类分析可划分为4个类型,其中桃之辉酢浆草、双色冰淇淋酢浆草、藤双色冰淇淋酢浆草亲缘关系较近;扁平酢浆草、黄花酢浆草、纳马夸纳酢浆草及兔耳酢浆草亲缘关系较近;大花酢浆草、星星酢浆草、乳白蝴蝶叶酢浆草亲缘关系较近;吉氏酢浆草和一片心酢浆草与其他酢浆草亲缘关系较远。该研究结果表明,花粉形态相近的物种在植株形态上有一定的相似性,花粉形态特征可作为种间亲缘关系研究和分类划分依据,进一步为酢浆草属植物杂交育种亲本选择提供理论基础。

8种蜀葵花型花粉形态

为探讨不同花型蜀葵(Alcea rosea)的花粉形态特征,选取8种不同花型的蜀葵花粉为试验材料,运用扫描电镜对花粉形态及外壁纹饰进行观测,通过聚类分析和主成分分析筛选适宜的指标进行聚类。试验结果表明:8种花型的蜀葵花粉均为单粒近球形,属很大型花粉,具大量散孔,外壁纹饰为二型刺状。经聚类分析发现,8种花型可分为3大类,类型Ⅰ包含星火型、玉蕊型、锦蕊型和复瓣型,表现为刺细长(刺长、刺基宽比≥2.29)的特征;类型Ⅱ仅疏球型,表现为花粉直径最小(直径<103μm),刺数量较多(刺数量>103枚)等特征;类型Ⅲ含单瓣型、火炬型和托桂型,表现为突起数量最多(突起数量>182枚),刺短粗(刺长、刺基宽比≤2.01)等特征。

中国特有种大理白前对高寒环境的形态适应特征

高寒草甸具有辐射强、低气压、风大、昼夜温度骤变等不利于植物生长的环境特征,为了探讨中国特有种大理白前(Cynanchum forrestii)对高寒环境的生态适应,以川西南九龙县高寒草甸(海拔3 100~3 500 m)的大理白前为对象,采用光学显微镜技术和扫描电镜技术研究了大理白前的形态解剖特征,并采用TCC法分析了花粉和种子的生活力。结果表明:大理白前的叶、茎、花均被有丰富的单列细胞组成的表皮毛;叶片和茎的表皮角质层较厚;叶的气孔较大而下生,栅栏组织和海绵组织发达;茎表皮细胞小、细胞壁厚,皮层由7层细胞组成,排列紧密,细胞内储藏有丰富的物质,维管柱所占比例较大,木射线数量较多,髓部发达且储藏物质丰富;根维管组织发达,皮层细胞储藏有丰富的物质;种子和花粉活力较高、合生花冠、合蕊柱、种子具有种毛,以及种皮厚而坚硬等特征为提高繁殖效率提供了保障。上述结果表明,大理白前具有一整套适应高寒环境的外部形态和内部结构特征,使其保持较高的抗辐射、抗旱和抗寒能力,为大理白前在高寒环境中成功生存和繁衍奠定了结构基础。

不同种源红砂的花粉形态特征研究

【目的】研究红砂花粉形态特征及其种内花粉变异程度,为红砂孢粉学研究与种质资源育种提供理论基础。【方法】以来自甘肃、宁夏、内蒙古并在试验地种植适应生长10余年的15个红砂种源花粉为材料,运用扫描电镜观测花粉性状指标;用Kolmogorov-Smirnow方法对各指标数据进行正态分布检验,对不同指标数据处理后进行种源间比较,计算其变异系数,采用组间连接法进行系统聚类分析。【结果】红砂花粉均以单粒形式存在,极轴长/赤道轴长为2.14(1.54~2.46),形状呈超长球形或长球形;极面观为三裂圆形具三沟,沟长长达两极,但不形成合沟;不同红砂种源的花粉形状和萌发沟数目相似。15个红砂种源的花粉大小为26.38(15.32~30.97)μm×12.37(10.06~14.50)μm,多为中型花粉粒;花粉萌发沟长为22.76(13.78~26.02)μm,萌发沟宽为0.39(0.14~1.66)μm,各种源萌发沟脊面形状宽窄不一,差异明显;萌发孔直径为0.21(0.16~0.27)μm,花粉外壁纹饰为细网孔纹饰,存在向极细网孔纹饰进化的趋势;不同红砂种源的花粉特征存在差异。各花粉特征指标的变异系数为4.39%~102.12%,种源整体变异程度较大,种源间存在遗传多样性。基于不同指标的聚类结果表明,各种源聚类距离远近与其花粉特征有关,其中花粉大小的影响较大;且甘肃酒泉瓜州(G-J-GZ)种源始终聚为一类,其花粉大小显著小于其他种源,属于较为原始的种质。【结论】不同种源红砂的花粉形状与萌发沟数具有遗传保守性,花粉特征具有遗传多样性,其中花粉大小可在一定程度上反映红砂种源间的差异性。

基于花粉微观特征的芒果属种质孢粉学研究及聚类分析

芒果属全球约有69个种,我国主要分布有8个种。我国悠久的芒果栽培历史形成许多具有地方特色的天然杂交种。在不断与环境协调发展的过程中,芒果枝叶、果实等外观形态发生了一定的变化,其花粉在保持遗传保守性和稳定性下却形成了独特的形态特征。为了深入研究芒果属植物花粉形态的分类学意义,理清芒果天然杂交种之间的系统发育关系,本研究基于花粉微观特征,对芒果属种质开展孢粉学研究及遗传关系分析。利用扫描电镜系统观察芒果属2个种32份芒果材料的花粉外部形态和花粉外壁纹饰等形态特征,在此基础上,对花粉6个数量性状进行聚类分析。结果表明:32份芒果种质花粉均属于N3P4C5型,极面观呈3裂三角形,赤面观呈近椭圆形,萌发沟孔为3条,萌发沟孔开裂度几乎到达花粉粒的两极;各材料的花粉形状大小、萌发脊宽窄、花粉纹饰、花粉外壁网孔密度和大小均存在差异;条纹状或网状纹饰和纹孔布满花粉粒表面,大多数芒果花粉属于网状纹饰,网孔形状多样,主要是圆形和长条形,纹脊粗糙,网孔分布密度在不同材料间存在差异。根据花粉粒大小、花粉形态、萌发脊宽、网孔大小和网孔密度等数量性状对参试材料进行聚类分析,32份芒果种质在相似距离为15时可分成三大类群,来自东南亚的马切苏、暹罗芒、仁和吕宋等芒果资源在谱系图中聚为一类,显示出一定的地域特征;萌发脊较窄的云南土芒、布鲁斯和象牙芒26号聚为一类;扁桃、收集的扁桃–芒与国内常见芒果栽培种聚为一类。原始的野生种白花本地芒与扁桃1号、扁桃2号、扁桃3号、扁桃4号聚为一组,该类资源具有原始型、野生型的特点。本研究可为芒果花粉形态的分类、亲缘关系和演化研究提供孢粉学依据。

Cytological Observation of Pollen Abortion of Lycium barbarum Haploids from Anther Culture

To reveal the sterility characteristics of Lycium barbarum haploids, cytological observations were made on the anthers of Ningqi No.1 and its haploids obtained from anther culture. The results showed that there were no significant differences in anther development between Ningqi No.1 and its haploids at the stage of pollen mother cell, and tetrads were formed successfully after the meiosis stage. The tetrads of Ningqi No.1 could release microspores. At the same time, the tapetal cells can provide nutrition for the development of the microspores, which eventually developed into mature pollen grains. Although the haploids could also release microspores at the tetrad stage, the tapetal cells degraded in advance, which made the released microspores unable to develop into mature pollen grains, resulting in pollen abortion of haploids.

14份寒地苹果资源花形态结构观察

以寒地14份苹果资源为试材,观察花器官并在扫描电镜下观察花粉粒。结果显示:花器官8个特征当中雄蕊数目、花冠直径和花瓣形状这3个指标可以作为区分不同苹果资源的主要参考指标。14份苹果资源花粉粒外形高度相似,属于辐射轴对称,赤面观全部呈窄椭圆形,具3条萌发沟并延伸至极面,极面观呈三裂三角形和三裂圆形;不同资源脊宽、脊距、萌发沟长、萌发沟间距和外壁纹饰差异较大。对花粉形态特征进行聚类,分析结果与传统植物学分类结果基本一致。

4种忍冬属植物花粉形态的数量分类及其活力比较研究

[目的]了解忍冬属物种的亲缘关系及花粉可育性,为忍冬分类和杂交育种工作提供科学依据。[方法]采集4种忍冬属植物新鲜花粉,分别进行花粉形态的扫描电镜观测及不同温度处理下花粉离体萌发的活力检测,并进行数据分析。[结果]忍冬属花粉均为球形或近球形(1.10≤P/E≤1.15),中等或大花粉,3或4环状萌发孔沟,外壁纹饰为较为粗糙的刺突。聚类分析表明,新疆忍冬与刚毛忍冬的关系最近,金银花与贯月忍冬在欧式距离12处聚为一类。新疆忍冬的花粉活力最强,达到56.04%,刚毛忍冬在各种温度处理下花粉活力相对较低,仅为15.23%,2种藤本忍冬花粉活力居中,为40%~50%。新疆忍冬和刚毛忍冬的花粉在中温环境下萌发最好,贯月忍冬和金银花的花粉在高温环境中更易萌发。[结论]花粉形态的数量分类结果与现行忍冬属植物分类系统大致吻合,可以指导杂交育种工作、花粉活力强的物种可作为杂交授粉的父本。