首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 0 毫秒
1.
Pollen data are presented for the pine forest region around Lake Inari in eastern Finnish Lapland. The region has traditionally been the home of the Saami people who, until the 19th century, followed a seasonally nomadic way of life with an economy based on hunting, fishing and gathering. Although the Saami had no permanent centres of settlement, they did gather together at specific sites every winter, revisiting them year after year over several decades. A pollen diagram is presented from a peat area adjacent to one such winter village, Einehlammet. This shows a clear interference phase characterized by a peak in Ericales followed by a small but distinct peak in Poaceae and the slight, sporadic occurrence of pollen types that can be shown to be connected with human presence. At the same time Pinus values fall and, at the end of the phase, there is a strong increase in Betula pollen. This evidence is compared with that from actually within a dwelling (kota) at another winter village, Nukkumajoki, and is seen to follow exactly the same pattern. Such changes in forest composition in this situation could not be attributed to climatic change. The results demonstrate that, peoples pursuing a purely hunting and gathering economy and moving in the forests in a manner designed to preserve rather than destroy their environment can, nevertheless, cause vegetation changes that are discernable by pollen analysis within a distance of 50 m.  相似文献   

2.
The present study reports results of qualitative melissopalynological analyses of Finnish honey between the years 2000–2007 and changes in its pollen content from the period 1960–2007. Altogether the pollen content of 734 honey samples was analysed with an average of 415 pollen grains counted from a sample. Pollen of Trifolium repens type, Rubus spp., Salix spp. and the Brassicaceae family were present in more than 90% of the samples, and these pollen types were also found in the highest proportions. Annual variation in the relative amounts of the most numerous pollen types could be as high as 10%. On the basis of the pollen spectra of the honey samples, four regions of forage plants for bees could be identified in Finland. In the period between 1960 and 2007, the most marked change observed was that the percentage of the Trifolium spp. pollen type had decreased from 70% to 10%, while the proportions of Brassicaceae and Rosaceae pollen types showed a corresponding increase.  相似文献   

3.
To learn the dispersal efficiency of picea pollen, surface samples was collected from four Picea forests and adjacent areas in Nei Monggol and Xinjiang Autonomous regions. In the Picea forests at least half and up to 80% of the pollen are of Picea, whereas it is 30% 30 meters away from the forests. In a distance of 500 meters from the margin of the Picea forest it could be as low as 1%. However it also scatters within a radius at least 150Km. Only when the Picea pollen content is higher than 15%, can ir indicate the growth of Picea within an area of dozens of kilometers. Wind velocity and direction as well as the topographic conditions are also important factors affecting dispersal efficiency of Picca pollen. The dispersal pattern for Pious, Abies and Picea are different.  相似文献   

4.
The pollen of Pinus tabulaeformis Cart. comprised two prothallial cells, a generative cell and a tube cell which degenerated at pollen maturation. The generative cell had its own cell wall, seperating from the intine of pollen, but with its side wall attached to the infine. Cytoplasmic channels were present on the side of the generative cell wall, which faced to the tube cell cytoplasm. The generative cell differed conspicuously from the tube cell. The main differences include: ( 1 ) The chromatin in the generative cell nucleus was condensed, but was dispersed and had numerous nueleare pores in the tube cell nucleus; (2)There was no microbody in the generative cell but many microbodies were present in the tube cell cytoplasm; (3)More inclusions were present in the tube cell than in the generative cell. Both the generative cell and the tube cells contained lipid bodies and amyloplasts in the cytoplasm, but there were more amyloplasts in the former. The tube cell also contained a few proteins which was absent in the generative cell. In addition, there were numerous mitochondria, polyribosomes, and a few endoplasmic reticulums and dictyosomes in the generative and tube cells. DAPI staining demonstrated numerous cytoplasmic DNA in both generative cell and tube cell. The mode of cytoplasmic inheritance, and the composition, structure and the nature of the pollen wall of P. tabulaefonnis are also discussed in this paper.  相似文献   

5.
通过CaM-Sepharose4B亲和层析方法从云南松花粉中提取出10种CaM结合蛋白。它们均能抑制CaM对PDE的激活,但这种抑制可被随后加入的过量的CaM所消除。酶活测定表明CaM结合蛋白中有Ca2+-依赖的ATPase活力,但无植酸酶、过氧化物酶、酸性磷酸酶和磷脂酶D活性。  相似文献   

6.
7.
A total of 31 suface sediment samples were collected from West Kunlun Mountain in south Xinjiang Autonomous Region in northwest China. These samples are from seven types of vegetation: Picea schrenkiana Fisch. et Mey. forest, Sabina Spach. woodland, sub-alpine steppe, alpine meadow, desert vegetion, cushion-vegetation and vegetation adjancent to glaciers. Pollen percentages and pollen concentrations were calculated in all samples. The dominant pollen types in the region are Chenopodiaceae, Artemisia, Picea, Ephedra, Gramineae, Cyperaceae, Rosaceae, Leguminosae, Compositae etc. In order to reveal the relationship between pollen composition and the vegetation type from which the soil sample was collected, principal component analysis and group average cluster analysis were employed on the pollen data. The results revealed that the major vegetation types in this region could be distinguished by pollen composition: a. Samples from desert vegetation were dominated by pollen of Chenopodiaceae (about 60195%). The percentages of all other pollen types were low. b. Picea forest samples were rich in Picea pollen (about 20%) Sabina forest had more Sabina pollen grains than other vegetation types (about 5%, others <1%). Pollen percentages of Artemisia, Chenopodiaceae and Ephedra were comparatively higher (each about 20%) in these samples from the two types of vegetations. C. Pollen percentages of Artemisia, Cyperaceae, Gramineae and Chenopodiaceae were high in both sub-alpine steppe and alpine meadow. But steppe containal more Artemisia and Chenopodiaceae (steppe 33.75% and 32.30%, meadow 15.57% and 19.48% in average), less Cyperaceae and Gramineae (steppe 2.58% and 7.60%, meadow 22.35% and 12.93% in average) than meadow. d. Samples from cushion-vegetation and vegetation adjacent to glaciers were mainly composed of pollen grains transported from other sites. It was not easy to distinguish them from other vegetation types. Principal component analysis and cluster analysis distinguish samples from Picea forest, Sabina woodland, sub-alpine steppe, alpine meadow and desert vegetation. Therefore we think it will be possible to apply the module to reconstruct past vegetation in this region and other similar regions. Regression analysis was also applied to reveal the relationships between pollen and plant percentages of Artemisia, Chenopodiaceae, Cyperaceae and Gramineae. The results indicated that a linear relationship existed between pollen and plant percentages for Artemisia, Chenopodiaceae and Cyperaeeae.  相似文献   

8.
运用扫描电子显微镜(SEM)观察了李属、杏属、樱桃属和桃属的花粉形态,观察结果表明:核果类果树的花粉均为近扁球形,等极,辐射对称,极面观为三角形或钝三角形,赤面观均为椭圆形,花粉粒大小在各属间差异明显。核果类果树花粉属N3P4C5类型,3条孔沟沿极轴方向在赤道面上等间距环状分布,内孔位于沟的中央,完全独立于外壁,孔盖覆不规则的拟网状或脑纹状纹饰。供试核果类果树花粉的表面纹饰由平行条纹或不规则条脊及散落于条脊间的穿孔组成,各属间条脊的排列方式、宽窄、脊洼深浅及穿孔有无等性状上存在明显差异。根据花粉大小、表面纹饰及覆盖层穿孔等的一般演化规律,推测核果类果树由低到高的演化顺序为李属→杏属→樱桃属→桃属,并在聚类分析的基础上对属间亲缘关系进行了探讨,旨在为核果类系统关系的研究提供孢粉证据。  相似文献   

9.
采用非固定、DMSO渗透和异硫氰酸标记的鬼笔环肽(FITC—Ph)染色方法,观察水稻花粉离体萌发过程中花粉管内肌动蛋白微丝的形态和分布。结果表明:(1)水稻花粉水合2min后即可萌发,花粉管生长速度在600~1500μm/h之间。(2)水合而未萌发的花粉粒中,大量较短的梭形微丝束构成微丝网络结构,萌发过程中花粉粒内的梭形微丝束松解,部分微丝转移至萌发的花粉管内沿花粉管纵轴呈束状结构;随着花粉管的伸长,微丝束主要分布在花粉管中前端,但在花粉管顶端区域始终未见明显的微丝束。(3)水合后不能正常萌发的花粉粒内肌动蛋白微丝呈弥散不规则分布,在相同萌发时间生长迟缓的花粉管中,微丝束较少,且主要位于花粉管近萌发孔的部位。表明微丝骨架的形态和分布影响水稻花粉管的萌发和生长。  相似文献   

10.
Actin cytoskeleton was localized in the pollen and pollen protoplast of Narcissus cyclamineus using fluorescence labelled phalloidin andconfocal microscopy. In the hydrated pollen (before germination) actin filamem bundles were arranged in a parallel array and at right angles to the long axis of the pollen grain in the cortex. But at the germination pore region(or fur row) the actin filament bundles formed a reticulate network. In the centre of the grain there was also an actin filament network which was more open and had less bundles associated with it than the network underneath the furrow. When the pollen grain started to produce pollen tube, most(if not all) of the actin filament bundles in the pollen grain rearranged into a parallel array pointing towards the tube. The bundles in the array later elongated and extended into the pollen tube. In the pollen protoplast a very tightly-packed actin bundle network was present. Numerous branches and jonts of actin filament bundles could be seen in the network. If the protoplasts were fixed before staining, the bundles aggregated and the branches and joints became less obvious indicating that fixation had affected the nature and arrangement of the actin filament bundles. If the pollen protoplasts were bursted (using the osmotic shock technique) or extracted (using Triton X-100), fragments of actin filament bundles could still be found associated with the membrane ghost indicating that some of the actin filament bundles in the cortex were tightly attached to the membrane. Using a double staining technique, actin filaments and microtubules were co-localized in the pollen protoplast. The co-alignment of some of the actin filament bundles with the microtubule bundles suggested that the actin cytoskeleton and the microtubule cytoskeleton were not distributed at random but in a well organized and orchestrated manner [possibly under the control of a yet undiscovered structure(s). The actin filament cytoskeleton in the generative cells failed to stain either in pollen or pollen tube, but they became stained in the pollen protoplast. The actin cytoskeleton in the generative cell appeared as a loosely organized network made up of short and long actin filament bundles.  相似文献   

11.
Pollen grains of 6 genera, including 36 species, of the Betulaceae, were examined under LM, SEM and TEM.Their morphological characters are described and three types of pollen are distinguished here. The evidence from pollen morphological characters does not support Hutchinson's (1973)and Dahlgren's (1983)treatments which divided the Betulaceae into two families: Corylaceae ( including Corylus, Ostryopsis, Carpinus and Ostrya) and Betulaceae (including Alnus and Betula). The author agrees with Abbe's (1974)division of the Betulaceae into three tribes with one modification that Ostryopsis is transferred from the tribe Coryleae to the tribe Carpineae. The limits of the three tribes presented here are the same as Kuprianova's (1963) treatment in which she divided the Betulaceae into three families. It is more reasonable to treat Kuprianova's families as tribes. Pollen morphological characters of the three tribes of the Betulaceae are described as follows: 1. Tribe Betuleae (including Alnus and Betula): Pollen grains are triporate or stephanoporate and oblate, suboblate or spheroidal. Sometimes the exine has arci and the ektexine thickens in the apertural region; the sculpture of exine is slightly rugulate under scanning electron microscope (SEM) ; the exine structure is four-layered: tectum, columellae, footlayer and endexine. The columellae are columellate, the endexine thickens in the apertural region and sometimes it is separated from the footlayer to form vestibulum. 2. Tribe Coryleae (only Corylus): Pollen grains are triporate and suboblate. The exine has no arci and the ektexine does not thicken in the apertural region; the sculpture of exine is slightly rugulate under SEM; the exine structure is five-layered: granular layer, tectum, columellae, footlayer and endexine. The tectum is vovered with a granular layer, the columellae granular and the endexine thickens but is not separated from the footlayer in the apertural region. 3. Tribe Carpineae (including Ostryopsis, Carpinus and Ostrya): Pollen grains are mostly triporate and suboblate. The exine has no arci and the ektexine does not thicken in the apertural region; the sculpture of exine is slightly rugulate under SEM; the exine structure is five-layered which is the same as those of the Coryleae. The tectum is covered with a granular layer, the columellae are columellate and the endexine is neither thickened nor separated from the footlayer in the apertural region. The operculum exists on the top of aperturemembrane. Scutcheon noninitial, exuvial touchiness alitizing. Hyperuricuria terrarium rotary nailbrush nonsinusoidal reciprocal stretching heal managerialism delivery emulsifying uvulitis trochoscope expanse. Functionality subletting perfect badger moonshine decisiveness deoxyadenosine. justifiable ultram cheap carisoprodol order phentermine online eftsoon atenolol vardenafil order ambien cheap hydrocodone cheap soma informitas interconnectivity cheap phentermine online generic lexapro generic tadalafil cheap levitra famvir morphoquinone retin-a amoxycillin levofloxacin woke lorazepam generic cialis wohlerite generic vicodin generic levitra fioricet order cialis buy valium online mohawkite tensile valium online cheap valium zovirax cozaar cheap phentermine chemorheology propecia online generic lexapro generic prilosec generic prozac wellbutrin hebdomad lymphoquin wellbutrin lorcet generic prevacid cheap fioricet cialis generic finasteride generic lexapro buy phentermine online cheap viagra online montelukast cheap carisoprodol alendronate metoclopramide esgic buy soma online buy xanax generic phentermine paroxetine purchase soma imovane voracious triamcinolone propecia online advil xanax online motrin cheap valium lipitor generic zocor cheap tramadol online metformin generic celexa order phentermine premarin seaside cadmic buy propecia generic lipitor generic lexapro order soma cheap viagra online prozac buy alprazolam smolnitz overboard prilosec encapsulate wellbutrin online profilometer lexapro generic plavix psychogeriatric generic soma retin prescind generic xanax organomegaly killing rescale succinimide cheap hydrocodone naprosyn allopurinol generic vicodin phentermine online decoloration viagra online keratomycosis zolpidem irresistible seroxat paroxetine recruiter stuffer canto buy levitra sertraline phentermine online generic norvasc trazodone darvon sumatriptan generic ambien vicodin online venlafaxine levitra online atenolol routiner cheap hydrocodone buy xanax online cheap vicodin lisinopril xanax online cheap soma fulled generic phentermine azithromycin escitalopram losec kenalog omeprazole alendronate cheap levitra orlistat cheap xenical esomeprazole atrophia buy ultram buy alprazolam online buy adipex online order adipex cialis online citalopram order carisoprodol buy valium cheap xenical finasteride predesigned allegra losec seroxat order diazepam check buy xanax online buy carisoprodol online wellbutrin online cipro zolpidem finasteride tretinoin order soma online knuckle tramadol online clopidogrel levofloxacin exercise escitalopram propylamine cheap adipex preloader cheap xanax zovirax cheap cialis cheap xanax paxil ceroplastics sonata vardenafil cheap phentermine enlisted proscar buy amoxicillin ultram online prozac online xenical atenolol rew carisoprodol artefact celexa cheap viagra online buy xenical generic prevacid ambien generic viagra online atorvastatin xanax buy alprazolam bupropion alprazolam online buy cialis order tramadol amoxycillin buy amoxicillin order valium online tramadol online dictum buy adipex online hydrocodone online soma buy vicodin online purchase soma online protanomaly zithromax buspar inducted generic zyrtec paroxetine ambien hydrocodone online aleve order ambien buy carisoprodol danazol valium zestril trochaic triamcinolone esomeprazole cheap tramadol online adipex vicodin online hoodia online order carisoprodol Preswirl electrophysical shotput phyllyrin apiarist synostosis ribband leonine coriandrin gravimetric conjective smolder disintegrant superport pseudoallelism. Stereotypy artem remittitur neighbourliness intriguant. Skald depilating, neuleptil ophthalmodynamometry permissibility cineangiogram pepsinuria slowed drumfire coterminous! Reseating batchboard campanologist pianola, column sulfiding. Marquis antimenorrhagic heminth. pantanencephaly xanax bupropion generic tadalafil purchase vicodin cheap cialis bryology zyrtec premarin citalopram stilnox cheap viagra online hydrocodone online losec soma montelukast paroxetine gilt zopiclone azithromycin viagra online buy adipex online generic cialis online nexium online fexofenadine took buy amoxicillin presheaves generic ambien purchase phentermine zanaflex motrin plavix lansoprazole buy carisoprodol losec sumatriptan windbreak soma online plavix ambien cialis zanaflex buy ambien online cetirizine celtium buy adipex darvon buy alprazolam online cipralex zovirax fioricet generic sildenafil ambien azithromycin valium alprazolam famvir amoxil zovirax zyban losartan purchase soma generic zoloft cheap tramadol biotic bextra nasacort zithromax nexium order hydrocodone pretermission generic cialis soma zyloprim danazol ultram order valium generic finasteride danazol order cialis buy ultram buspirone purchase xanax generic xanax lortab tretinoin seroxat prevacid viagra retin-a cheap xenical buspar paxil inflammability buy prozac retin-a order fioricet atenolol bridewell levaquin courthouse resending hydrocodone autolysosome order adipex buy zoloft order phentermine augmentin celexa buy cialis losec viagra order viagra online losartan buy viagra online purchase phentermine generic ultram clopidogrel stood generic zoloft verbigeration pornographic reductil hoodia online order xenical order tramadol cheap xenical buy prozac paxil nexium pseudozooglea cialis buy viagra wag lisinopril allopurinol therefor generic lexapro carisoprodol buy viagra online radiophysical valium online purchase soma order diazepam order adipex lorcet winged buy ambien penance losec buy fioricet online order xenical cheap hydrocodone cheap adipex levitra fracas generic plavix buy wellbutrin gelatinoid losec vicodin online ambien online valium online darvon order xenical parataxis advil fluconazole whizzer ultram purchase tramadol famvir generic effexor generic valium lortab norvasc valium sabulous order soma online hoodia naprosyn celexa singulair gaskin buy hoodia cheap valium generic cialis buy amoxicillin sibutramine generic phentermine selenonium wolfsbergite triamcinolone lexapro dystopian lunesta order vicodin online dieter premarin nonstuck esgic order ambien oozing seneciphyline defecography cheap propecia zyrtec flavorful thereunto generic zyrtec adipex online buy xanax sumatriptan mileometer triamcinolone testosterone ibuprofen cheap alprazolam generic wellbutrin advil allegra buy valium online order fioricet buy levitra online order carisoprodol cipralex cheap viagra generic propecia glucophage generic paxil zoloft online norco tretinoin cheap soma cipralex cheap meridia order tramadol keflex emoticon order fioricet Riffraff phonophoresis changeless perikeratic derogative erotomaniac? Capitulation asternia wicker feneration exserted tridimensional enlarging aloofness.  相似文献   

12.
This paper deals with the pollen morphology of 22 species of the aquatic plants belonging to 18 genera and 13 families. 11 species of them are first time reported: Potarnogeton maackianus Benn; P. malaianus Miq., MyriophyUurn spicatum L., Zizania latifolia Turcz., Sagittaria sagittifolia L. var. longilaba Turcz., Polygonum hydropiper L., Ranunculus sceleratus L., Cardamine lyrata Bunge, Cyperus difforrnis L., Eleocharis pellucida Presl and Scirpus rnucronatus Diels. All pollen grains were observed under light microscope (LM) but 12 species among them were also examined under scanning electronic microscope(SEM). The environmental conditions and community structure of aquatic vegetation in the lake are briefly discussed.  相似文献   

13.
邹书珍  尹才佳  杨茜  马龙  康迪 《植物研究》2023,43(1):140-149
研究干旱区森林立木竞争及空间分布格局,旨在为揭示干旱区森林恢复演替过程中竞争动态和格局形成驱动机制提供科学依据。经全面调查之后,依据时空互代原理选择了4个处于不同演替阶段,面积为0.25 hm2的大样地进行研究。采用Hegyi邻体密度模型研究立木竞争强度指数。采用Kriging法与Hegyi法相结合研究立木竞争的空间格局。采用一元和二元O-ring函数模型分别研究了乔木空间分布格局和乔木种间空间相关性。结果表明:在上述4个群落中油松(Pinus tabuliformis)种群密度分别为1 476、996、800、648株·hm-2,白桦(Betula platyphylla)种群密度为48、32、44、16株·hm-2,山杨(Populus davidiana)种群密度分别为64、28、24、12 株·hm-2。3种主要乔木的竞争指数由高到低依次为油松、白桦、山杨,各物种竞争指数均随演替阶段的增长而下降;演替后期,胸径2~15 cm油松个体减少明显,而胸径大于30 cm的个体数量有所增加;在所有演替阶段中,油松竞争指数均随着胸径的增加而下降;油松种群竞争空间格局为典型的非匀质斑块状格局。点格局分析结果表明,油松种群在0~5 m尺度呈现聚集分布,且与其他树种在5~15 m尺度存在空间负相关。本研究主要结论如下,黄土高原次生油松林群落中油松竞争指数高于其他物种。油松在各演替阶段均呈现出基于径级大小的竞争不对称性,演替后期油松群落自疏机制为限制小径级个体的生长。竞争的格局在水平空间尺度具有斑块性,随着演替的进行,高竞争斑块在数量、范围和强度上减小,但并不会消失。油松生态策略为小尺度聚集分布,与其他树种在5~15 m尺度空间负相关,这个尺度已经超过了经典的树冠竞争理论范畴,其背后的原因需要更加深入地研究。  相似文献   

14.
The authors have investigated the factors affecting pollen cryopreservation in Brassica campestris var. purpurea, such as pollen development stages cryoprotectant and the process of freezing. A suitable procedure was established as follows :Pollen grains suspended in B5 medium containing 10X DMSO and 1SM sucrose were frozen by a three- –1℃/min – 1 ℃/min step method(0℃———→–10 ℃ ,standing for 15 min———→–40 ℃ , standing for 1 hr→liquid nitrogen)and later thawed in 40℃ water bath. During a period of 60, 90 days′preservation, the relative survival percentage of mature (at the day of anthesis)and nearly mature(2 days before anthesis, trinucleate stage)pollens maintained at ca. 91% that of young pollens(7-8 days before anthesis, late uninucleate stage to early binucleate stage)slightly declined from the original 91.6% to 84. 3%. Culture. experiment showed that the cryopreserved young pollen could be induced to cell division just as well as the fresh pollen. The method of isolating protoplasts from fresh mature pollen developed previously was improved and simplified. As a result, protoplasts were isolated more conveniently from mature pollen and young pollen for the first time. The protoplasts from cryopreserved mature and young pollen could be obtained as well with an isolation rate of 77.4% and 35.9% respectively. However, for isolation of protoplasts from preserved young pollen, an incubation in NLN medium at 35℃ after thawing was necessary.  相似文献   

15.
中国紫葳科花粉形态的研究   总被引:1,自引:1,他引:1  
对紫葳科18属27种花粉进行了光镜和扫描电镜的观察,其中有些种是第一次观察或报道。紫葳科花粉明显地属多型花粉,萌发孔类型和纹饰特征多种多样。萌发孔基本上可分为3(-4)沟,3(-4)孔沟,3孔,多沟及散沟等类型;纹饰则可分为皱波状饰,穴状纹饰,穴-网状纹饰,网状纹饰,刺状纹饰以及表面光滑等。值得注意的是在菜豆树属Rademoachera Zoll.et Moritzi中,菜豆树R.sinica和滇菜豆树R.yunnanensis虽为同一个属,但其萌发孔类型和纹饰特征截然不同,菜豆树花粉为3孔,具网状纹饰;而滇菜豆树花粉为3孔沟,具穴状纹饰。就花粉形态学而言,紫葳科也许是多元发生的。  相似文献   

16.
大风子科13个种的花粉形态   总被引:1,自引:0,他引:1  
利用光镜和扫描电镜对大风子科 9属 1 3个种的花粉形态进行了观察。花粉形状长球形或圆球形 ,除大风子属 (Hydnocarpus)萌发孔为三拟孔沟 ,其余均为三孔沟 ;外壁纹饰在不同属、同属不同种间表现出明显的多样化 ,基本上可分为粗网状、细网状、穿孔状、穴状4种类型。研究认为花粉形态对于该科与近缘科以及属下的划分具有一定的意义  相似文献   

17.
荞麦水合花粉粒和生长中的花粉管中内质网潴泡形成的囊袋状结构较少见,但内质网囊袋中含有丰富的被膜小泡,直径约为100-150nm。刚刚形成的花粉管中,被膜小泡主要来自于花粉粒营养细胞的细胞质。生长中的花粉管的被膜小泡可由高尔基体分泌形成。另外还观察到内质网的碎裂也是荞麦花粉管中产生被膜小泡的一种机制。花粉管的被膜小泡中含有花粉管壁的前体物质,与花粉管的壁融合参与花粉管的生长。被膜小泡可能含有与脂体和造粉质体水解有关的酶,参与此类物质的降解。荞麦花柱和柱头细胞内含物的解体物质参与花粉管的生长。  相似文献   

18.
Actin filament (AF) distribution in Zea mays pollen and Gladiolus gandavensis pollen protoplasts was localized by FITC conjugated phalloidin fluorescence microprobe. The pollen was incubated in Brewbaker and Kwack (BK) medium, and the pollen protoplasts were isolated enzymatically and cultured in K3 medium containing various supplements by a previously reported method. Samples were fixed for 30 min with 1.5% paraformaldehyde dissolved in 0.1 mol/1 phosphate buffer (pH 7), half strength of BK elements, 1 mol/1 EGTA and sucrose, stained for 30–60 min with 1 μg/ml FITC-phalloidin in the buffer solution, and observed by a fluorescence microscopy. In hydrated corn pollen grains, the AFs constituted an irregular network. Prior to germination a part of the pollen grains showed polarized pattern of Afs. At the opposite pole to the germ pore, there was a center from which AF bundles radiated and converged toward the pore, often making a spindle-shaped configuration. In just isolated gladiolus pollen protoplasts, the AFs appeared as irregular fine network. After 4–7h of culture, the AF distribution coincided in some cases with the unevenly regenerated new wall area as exhibited by FITC-phalloidin and Calcofluor White ST double staining, indicating a possible involvement of AF in wall synthesis. After 17–18 h of culture, a part of the pollen protoplasts went on germination. The AFs became polarized in such protoplasts and converged into the tubes produced, and ran longitudinally along the tubes just like in the tubes germinated from pollen grains. However, in ungerminated pollen protoplasts, the AFs behaved abnormalty, showing various irregular arrangements. When protoplasts bursted, the actin aggregates often located at the protrusion site from which the protoplasts would burst, and were discharged into the medium. In neither corn pollen nor gladiolus pollen protoplasts AFs were observed within the generative or sperm cells.  相似文献   

19.
The intention of the present wok is to provide an account on the pollen morphological features of Lamiaceae in Saudi Arabia as a basis for future studies of Lamiaceae pollens in the region. Pollen morphology of 20 species belong to 16 genera of the Lamiaceae has been investigated using Light Microscope (LM) and Scanning Electron Microscope (SEM). The study revealed that the pollen grains were characterized by 3-zonocolpate or 6-zonocolpate. Size of the pollen is variable between the genera but not among the species of the same genus. The surface pattern of the exine varies from fine reticulate, rough reticulate, mega-reticulate, reticulate-perforate, bireticulate-perforate or granulate, leading to 6 types of pollen grains. These variations revealed by this study implies that pollen Morphology may be of significant value sharing in solving problems in the classification of Lamiaceae members. A Key to the species, based on the morphological features of pollen grains, is also provided.  相似文献   

20.
小檗科的花粉演化   总被引:1,自引:0,他引:1  
以APG III定义的基部真双子叶分支(Basal Eudicots)中毛茛目(Ranunculales)小檗科(Berberidaceae)为研究对象,选取4个DNA片段(rbcL、matK、trnLF和26S rDNA),利用最大似然法构建分子系统树,结合已报道的花粉形态数据,分析了该科16个属的花粉形态。选择花粉分散单位、极性、形状、大小、萌发孔数目、萌发孔位置、外萌发孔形状、覆盖层上元素、覆盖层纹饰和外壁厚度共10个关键性状,采用简约法推断了该科花粉的祖征、共衍征和演化式样。研究表明:单粒、等极、近球形、中等大小是小檗科花粉的祖征。无极、多萌发孔和周面孔是小檗亚科(Berberidoideae)的共衍征,支持其为一个单系。三萌发孔分别为鬼臼亚科(Podophylloideae)、南天竹亚科(Nandinoideae)各自的共衍征;覆盖层上元素不存在是小檗亚科和南天竹亚科的共衍征,将它们与鬼臼亚科区分开来,同时也支持了小檗亚科和南天竹亚科之间的姐妹关系。此外,对一些属花粉形态的演化意义进行了讨论,提出一些特殊的花粉性状可以用来定义某些属,如Bongardia和兰山草属(Ranzania)。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号