Palyno-stratigraphy of the Ketewaka coalfield (Lower Permian), Tanzania

Palynological studies of outcrop and borehole samples from coal-bearing Karroo (Lower Permian) deposits in the Ketewaka area of southwest Tanzania show a distinct change in the composition of spore/pollen assemblages approximately in the middle of the sequence, the most prominent feature being differences in the representation of monosaccate and disaccate species. This is in line with results of earlier studies in the adjacent Mchuchuma area.The change in spore/pollen content is taken as evidence of a considerable floral change affecting an extensive area and probably climatically controlled.The floral change coincides with a distinct change in sedimentation, from sand with coal to mud or clay with coal, except for a part of the Ketewaka area, where sandy sediments continued to be deposited.     

葫芦科8属11种植物花粉形态的扫描电镜观察

利用扫描电子显微镜,对葫芦科8属10种1变种植物的花粉形态进行观察研究。结果显示:冬瓜属、葫芦属和栝楼属的花粉粒为近球形,具3孔沟;苦瓜属、西瓜属和丝瓜属的花粉粒为长球形,具3沟;黄瓜属的花粉粒为近球形,具3孔;南瓜属的花粉粒为球形,具散孔。花粉粒大小、形状和外壁雕纹属、种间差异显著。     

Pollen Morphology of Guttiferae in China

The present paper deals with the pollen morphology of 23 species belonging to 6 genera of Guttiferae occurred in China. All pollen grains have been observed under light microscope, and those of 11 species in 5 genera have been examined with SEM as well. The pollen grains of Guttiferae are subspheroidal, spheroidal or prolate, (17–43) × (15–26)μ in size. Mostly 3-eolporate, less frequently 4-colporate or 5-colporate. The exine is 2-layered, but the occassionally demarcation of these layers is generally indistinct. The exine is 0.8–2.6 μ in thickness. The oramentations of all the pollen grains is generlly finely reticulate under the light microscope. Pollen morphology of the 11 species of 5 genera observed under the SEM is stressed. Their exine oramentations may be classified into four major groups, ie. reticulate, finely reticulate, baculate and perforate. Calophyllum: pollen grains reticulate and rugulo-reticulate. Cratoxylon: pollen grains reticulate, with finely and densely granulate over entire muri. Gareinia: pollen grains baculate, reticulate, and exine with perforate oramentation; in reticulate grains, muri with spinulation. Hypericum: pollen grains reticulate, perforate and finely reticulate. Mesua: pollen grains finely reticulate. From the comparison of pollen morphology, Hypericaceae has much connection with Guttiferae (sensu stricto). Because their pollen grains are all 3-eolporate and the exine is reticulate or oerforate under light mieroseope, but it is different between the pollen grains of Hypericum and those of Guttiferae.     

云南松花粉形态研究

在云南松(Pinus yunnanensis Fr.)小孢子发生发育过程中,花粉母细胞、四分孢子及花粉粒均见有粘连现象。花粉气囊的形态、大小变化复杂多样。除一般具两个正常气囊的花粉粒外,还观察到气囊不发育、具一个气囊、二个异形气囊、三个气囊和四个气囊的花粉粒。成熟花粉壁从外至内可分为外壁外层、外壁内层、内壁外层和内壁内层,它们的构成成分及形态均有明显差别。贮存后花粉的内壁结构发生了明显变化。     

Rapid Swelling of Pollen Grains in the Dehiscing Anther of Two-rowed Barley (Hordeum distichum L. emend. LAM .)

The role of rapid swelling of pollen grains in anther dehiscencein Hordeum distichum L. emend. L AM. and the mechanism of thisswelling were examined. Artificial opening of the floret inducedrapid swelling of pollen grains and thecae dehiscence. The thecadehisced as pollen grains became swollen and dehisced anthershad larger pollen grains than indehisced anthers. Septa in theanther segments dehisced as a result of water-induced pollenpressure. These results strongly support the theory that therapid swelling of pollen grains is a driving force for antherdehiscence. On the other hand, potassium was detected in pollengrains from dehisced anthers, but not in pollen grains in indehiscedanthers. This suggests that potassium ions function as a turgorregulator in the rapid swelling of pollen grains. The mechanismof anther dehiscence is discussed in relation to the swellingof pollen grains, as is the possible mechanism of this swelling.Copyright 2000 Annals of Botany Company Anther dehiscence, Hordeum distichum L. emend. L AM., pollen swelling, potassium ion, two-rowed barley     

Airborne Pollen Grains of Bozüyük (Bilecik, Turkey)

Airborne pollen grains in the atmosphere of Bozüyük were investigated over a 2 yr period from 2000 to 2001 using a Durham sampler. A total number of pollen grains of 5 170 pollen grains belonging to 32taxa were identified and recorded along with some unidentified pollen grains. Of all the pollen grains, 78.66%were arboreal, 19.20% were non-arboreal, and 2.12% were unidentified. The majority of pollen grains investigated were Pinus, Platanus, Quercus, Cupressaceae, Poaceae, Fagus, Salix, Rosaceae, Urticaceae,Asteraceae, and Chenopodiaceae. The maximum number of pollen grains was recorded in May.     

Histoenzymological compartmentation of β-glucuronidase in the germinating pollen grains ofPortulaca grandiflora

The contribution deals with the distribution of β-glucuronidase in the germinating pollen grains ofPortulaca grandiflora. In non-germinating pollen grains the enzyme is localized in the pollen wall; the cytoplasmic activity is subdued. With the initiation of germination, the activity of enzyme increases and the positive granules are richly packed in the pollen grains and pollen tubes. The stigma hairs also have such an activity. The functions of the enzyme in the metabolism of germinating pollen grains are discussed.     

胡椒科的花粉形态及其分类学意义

胡椒科的某些属之间,花粉形态表现出一定的差异。齐头绒属花粉粒表面粒为平滑,但有小穿孔,略显粗糙。胡椒属的花粉粒表面有不规则的瘤状纹饰,纹饰较为平滑。Ｌｅｐｉａｎｔｈｅｓ（Ｐｏｔｈｏｍｏｒｐｈｅ）的花粉粒表面瘤状纹饰不显著。     

In vitro pollination in poplar of section Populus

Two methods of in vitro pollination of aspen were tested and compared, first with moist pollen by transferring swollen pollen grains from a wet agar surface to the stigma and, second, using dry pollen grains. In vitro pollination with dry pollen grains appeared to be more efficient and this method was applied in three subsequent years. Additionally, pollination was performed with selected pollen grains in order to obtain triploid plants. Diploid pollen was induced by heat-treatment of pollen mother cells, but the enrichment of unreduced pollen from natural pollen mixtures was also successful. The selection of diploid pollen, which is larger in diameter than haploid pollen, was performed by sieving using micro sieves. Five triploid plants from different poplar combinations were obtained from 1,227 zygotic embryos cultured after in vitro pollination of 2,676 ovaries with dry pollen over 3?years. Embryo rescue was used to facilitate the development of immature zygotic embryos. The results of this study demonstrate the possibility to effect pollination using selected single pollen grains with the help of in vitro techniques.     

Airborne Pollen Grains of Bozuyuk （Bilecik, Turkey）

Airborne pollen grains in the atmosphere of Bozuyuk were investigated over a 2 yr period from 2000 to 2001 using a Durham sampler. A total number of pollen grains of 5 170 pollen grains belonging to 32 taxa were identified and recorded along with some unidentified pollen grains. Of all the pollen grains, 78.66% were arboreal, 19.20% were non-arboreal, and 2.12% were unidentified. The majority of pollen grains investigated were Pinus, Platanus, Quercus, Cupressaceae, Poaceae, Fagus, Salix, Rosaceae, Urticaceae, Asteraceae, and Chenopodiaceae. The maximum number of pollen grains was recorded in May.     

Detection and release of allergenic proteins in Parietaria judaica pollen grains

Summary. Rapid diffusion of allergenic proteins in isotonic media has been demonstrated for different pollen grains. Upon contact with stigmatic secretion or with the mucosa of sensitive individuals, pollen grains absorb water and release soluble low-molecular-weight proteins, these proteins enter in the secretory pathway in order to arrive at the cell surface. In this study we located allergenic proteins in mature and hydrated-activated pollen grains of Parietaria judaica L. (Urticaceae) and studied the diffusion of these proteins during the first 20 min of the hydration and activation processes. A combination of transmission electron microscopy and immunocytochemical methods was used to locate these proteins in mature pollen and in pollen grains after different periods of hydration and activation processes. Activated proteins reacting with antibodies in human serum from allergic patients were found in the cytoplasm, wall, and exudates from the pollen grains. The allergenic component of these pollen grains changes according to the pollen state; the presence of these proteins in the exine, the cytoplasm, and especially in the intine and in the material exuded from the pollen grains, is significant in the hydrated-activated studied times, whereas this presence is not significant in mature pollen grains. The rapid activation and release of allergenic proteins of P. judaica pollen appears to be the main cause of the allergenic activity of these pollen grains. Correspondence and reprints: Department of Plant Biology, Faculty of Biology, University of León, Campus de Vegazana, 24071 León, Spain.     

The seasonal variation of airborne pollen grains that cause sugipollinosis in japan in the last three years

In Japan, the problems of Sugi (Cryptomeria japonica)-pollinosis have been much discussed in recent papers and journals. The author made an investigation on the airborne pollen grains from a scientific standpoint in connection with the incidence of pollinosis. By using the Cascade Impactor the author collected 600 liters of air sample a day, at the roof of the Pharmaceutical Science Building, Toho University, Funabashi, Chiba, Japan. Each air sampling for 2 hrs was repeated three times a week since 1969. The airborne pollen grains in each sample were counted under the microscope to identify the pollen types. The pollen grains were classified into six types according to the classification of pollen grains in Japan established by lkuse. The accumulated number of pollen of each species was analysed statistically by circular plot, Weibull plot, Edwards plot and semi-logarithmic plot. In this report mainly 3B type of pollen grains (Cryptomeria, Chamaecyparis), collected in the last three years are described. The total number of pollen grains in 1988 (2820 grains) was doubled in quantity as compared with that in 1987 (1177 grains) and in 1989 (1121 grains). The 3B type of pollen grains in 1988 (1450 grains) was 3.4 times as many as in 1987 (397 grains), and 12.9 times as in 1989 (112 grains). The 3B type of pollen grains represented the major portion of total pollen, and influenced the annual amount and the dispersal period.     

Transient expression and analysis of fluorescent reporter proteins in plant pollen tubes

The pollen tube is an excellent single-cell model system for studying cellular processes in plant cell biology. This protocol describes a detailed step-by-step procedure with optimized conditions for introducing various fluorescent reporter proteins into lily, tobacco and Arabidopsis pollen grains by means of biolistics for their transient expression and subsequent analysis in germinating pollen tubes. The whole experiment consists of four major stages: coating gold microcarriers with DNA constructs, preparation of pollen grains, transformation of plasmid DNA into pollen grains by particle delivery system and germination of bombarded pollen grains in optimized germination media to obtain pollen tubes for protein trafficking, protein localization, drug treatment and organelle dynamics analysis. This protocol takes about 4-12 h from pollen preparation to protein detection.     

Pollen size in Carex: The effect of different chemical treatments and mounting media

Pollen size and pollen aperture size for ten species of the genus Carex L., native to Estonia, have been measured using light microscopy. The species selected represent different sections of the genus, a range of habitats and different chromosome numbers. The effects of two basic chemical treatments, two mounting media and the effect of chemically induced dehydration with tertiary butyl alcohol (TBA) on the size of pollen grains were then recorded.

In general pollen size and pollen aperture size of the species examined is highly variable at both intraspecific and interspecific levels. Carex hirta has notably larger pollen grains than any of the other species investigated and, although correlations between size and chromosome number in the species examined are limited, it also has the highest chromosome number. Statistically significant size differences resulted from variations in chemical treatment, mounting media and tertiary butyl alcohol (TBA) induced dehydration. Acetolysed pollen grains are larger than potassium hydroxide (KOH) treated pollen grains. Pollen grains dehydrated after chemical treatment with TBA are larger than pollen grains not dehydrated. Pollen grains mounted in silicon oil are smaller than grains mounted in glycerine. But considering the great size variation of Carex pollen grains, the size changes caused by preparation procedures fall within the size variation range of the species examined.

All the samples contained a high number of deformed pollen grains and pollen grains with hardly distinguishable or no lateral apertures.     

中国特有属牛筋条属的花粉形态与其系统位置

从发育的角度研究了中国特有单种属DichotomanthesKurz及与其系统学研究有关的外类群Prinsepiautilis的花粉形态 ,扫描电镜观察显示Dichotomanthes花粉粒自脱离四分体胼胝质膜开始至成熟二核花粉粒不同发育时期 ,花粉形态和外壁纹饰未见变化 ,仅花粉体积随成熟度增加而有所增大。而Prinsepiautilis ,其花粉粒刚脱离四分体时形状和成熟花粉明显不同 ,成熟花粉极面观为三裂圆形 ,赤道面观为圆形 ,外壁具清晰的平行条纹 ,但幼嫩花粉粒的形状很特别 ,极面观为深三裂圆形 ,赤道面观亦见花粉在两条沟之间下陷而沟部外突 ,明显为角萌发孔花粉 ,且花粉体积较成熟者小 ,而外壁纹饰同成熟者相比无根本性差异。前述两种植物花粉在不同成熟期体积有明显差异 ,而外壁纹饰在不同成熟期不存在质的变化并相对稳定 ,说明花粉外壁纹饰这一性状在蔷薇科中具有较为重要的分类学意义。DichotomanthesKurz具典型Rosaceae花粉的三孔沟结构 ,外壁具条纹 -穴状纹饰。将其孢粉学特征同Rosaceae 4个亚科有关类群的同类资料相比较 ,并结合其它形态解剖与细胞学等研究结果 ,支持将Dichotoman thes置入Maloideae下而不赞同将其另立亚科或置于Prunoideae之下。此外 ,由于Prinsepiautilis的花粉在其发育初期具角萌发孔花粉 ,与Cunoniacea     

The Formation of Pollen Dimorphism in Paris axialis in Vivo

It is obsreved that the dimorphic populations of pollen are producedin Paris axialis H. Li In vivo. The normal pollen grains and abnormal pollen grainsare 77.1% and 22.9% respectively; more than 70% of abnormal pollen grains conformto the equal nucleus type. The abnormal pollen grains show no delayed development,and thay are stained as dark as the normal ones. During the first mitotic division of microspore, most of the spindles are anticlinal(perpendicular to the intine), the cytokinesis is generally asymmetric, and a completewall is formed. However, a few mitotic spindles of mitotic microspores are periclinal,and the cytokinesis are symmetric. Sometimes a partial wall is observed between twodaughter nuclei, which are produced by the abnormal pollen grains. We believe thatthese phenomena are related to differentiation of the dimorphic pollen.     

An analysis of cedar of Lebanon (Cedrus libani A. Rich.) pollen grain development in cultural plantings]

A cytological study of the Cedrus libani mature pollen from 3 culture areas (Italy, France, USSR) has shown that 69-71% of pollen grains have two-celled protallium and antheridial cell. About 5% of pollen grains are characterized by accelerated of delayed development, otherwise apparently normal. The pollen sterility (up to 30% of grains) is due to the abortive spore development. Anomalous cenocyte and multinuclear pollen grains were found thus suggesting that multicellular haploid structures capable of further growth and development may arise in the course of natural anther development.     

Histochemical studies on the distribution of 5-nucleotidase in the germinating pollen grains ofEschscholtzia californica cham.

The present paper incorporates a detailed study on the distribution of 5-nucleotidase in the germinating pollen grains ofEschscholtzia califomica. The intense activity of this enzyme has been found in the wall of pollen grains and pollen tubes and small positive granules in the lumen of both in the pollen grains and pollen tubes. The presence of this enzyme in the wall is presumably connected with the permeability and transport process and growth regulation of the pollen tubes.     

Exploding pollen in Montrichardia arborescens (Araceae)

Pollen grains of Montrichardia are inaperturate with psilate ornamentation. The pollen wall is formed by a thin ectexine and an extraordinarily thick intine. In living as well as in dead pollen grains contact with water leads to a rapid swelling of the intine followed by an explosive opening of the exine. Within a few seconds a thick tube is formed, which is not the pollen tube. The pollen protoplast is situated at the tip of the tube. These intine tubes are interpreted as pollen connecting tools to keep pollen grains together and adhere them to the cuticle of the hairless pollinators.     

Studies On the Pollen Morphology of the Genus Iris in China

In this paper, pollen grains of 32 species of the genus Iris in China were examined under light microscope and scanning elrctron microscope. Pollen grains in Iris of China are navicular or subspheroidal. According to the characters of aperture and shape, pollen grains may be divided into four types: (1) Monocolpate (distal): pollen grains navicular or subspheroidal, exine reticulate. (2) Monocolpate-colpoidal: pollen grains subspheroidal, exine pilate. (3) 2-syncolpate: polen grains subspheroidal or navicular, exine reticulate. (4) No aperture: pollen grains subspheroidal; exine verrucate. The evolutional trends of aperture and exine ornamentation are traced and systematic po-sitions of some species are discussed based on characteristics of pollen grains and other organs.