共查询到20条相似文献,搜索用时 15 毫秒
1.
P. P. Sood 《Biologia Plantarum》1974,16(2):102-106
The study deals with the distribution of non-specific esterase in germinating pollen grains ofPortulaca grandiflora. Intense activity of the enzyme is seen in small granules distributed homogeneously in pollen grains stigma hairs and throughout the length of pollen tubes. Further the walls of pollen grains also demonstrate intense activity. The functional significance of the enzyme in these locales has been discussed. 相似文献
2.
P. P. Sood 《Biologia Plantarum》1980,22(2):124-127
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. 相似文献
3.
Penetration of pollen tubes through stigmatic tissues in Brassica napus L. may involve the release of cell wall modifying enzymes from the pollen tube tip. We examined the expression of a pectin-degrading
polygalacturonase (PG) enzyme in unpollinated and early and late pollinated stigmas via immunoblotting and immuno-light microscopy
using a PG polyclonal antibody. Immunoblotting analysis indicated that PG enzyme was present at low levels in unpollinated
stigmas and at high levels in pollinated stigmas. The level of PG did not detectably increase between early and late pollinated
stigmas. Immuno-light microscopy demonstrated that PG enzyme was present in ungerminated pollen grains, stigmatic papillae
and in the tip of pollen tubes growing into the papillar wall. This latter evidence suggests that PG enzyme may play an important
role in papillar cell wall penetration during pollination although other interpretations of the role of pollen PG should not
be discounted.
Received: 9 November 2000 / Accepted: 7 December 2000 相似文献
4.
E. Bednarska 《Biologia Plantarum》1992,34(3-4):229-240
Two types of esterases, nonspecific esterase and cholin esterase have been distinguished in germinating pollen grains and in pollen tubes ofVicia faba using cytochemical methods. The localization of each of them was different. In the hydrated non-germinating pollen grain the nonspecific esterase was present in the cytoplasm and in the intine. The cholinesterase was localized mainly in the sexine and on the outside of the plasma membrane. A particularly large agglomeration of this enzyme was found in the aperture. During germination both types of extracellular esterases were released into the medium. In the pollen tube the activity of the enzymes studied was connected with the wall of its tip. The localization of both types of esterases in the germinating pollen grain and the growing tube were independent of actinomycin D. Cycloheximid prevented the cholinesterase localization at the pollen tube tip. 相似文献
5.
V S Polito 《Cell biology international reports》1985,9(11):1013-1016
The impermeable callosic wall that surrounds germinating pollen grains and pollen tubes is removed by brief treatment with Zymolyase, an enzyme preparation that hydrolyzes linear glucose polymers with beta-1,3 linkages. Zymolyase treatment does not interfere with pollen tube growth or cylosis in the vegetative cell. 相似文献
6.
The effect of medium concentration, pollen grain concentration, pH of the media, light and temperature on the germination of Vin ca rosea pollen grains, and the growth of their pollen tubes in vitro have been studied. The pollen grains germinate best at a sucrose concentration between 14.2% and 30%; when the pollen grain concentration exceeds 800 per 0.0234 ml; at near neutral pH (6.5); in darkness and at a temperature close to 30°. Moreover buffering ions affect the growth of the pollen tubes. Pollen grains remain viable in a wide range of temperatures, and the wall of the pollen grain is capable of withstanding severe osmotic imbalance. Low temperature induces spherical swellings at the tips of the pollen tubes, followed by accumulation of a hyaline plug. 相似文献
7.
Cell-wall proteins of pollen grains, in-vitro-germinated pollen and young roots of Lilium longiflorum were studied by gel electrophoresis and amino-acid analysis. The proteins were removed from extensively purified walls by successive saline and alkali extractions. The major part including the hydroxyproline-containing proteins is covalently bound to the wall. Clear differences were observed between the proteins, especially the glycoproteins, of the pollen grain and the pollen tube. During elongation of the tubes some proteins decrease in quantity and many new proteins appear. The amount of protein in the cell walls is much lower in roots than in pollen and the root cell walls also contain fewer glycoproteins. 相似文献
8.
Penetration of the Stigma and Style Elicits a Novel Transcriptome in Pollen Tubes,Pointing to Genes Critical for Growth in a Pistil 总被引:1,自引:0,他引:1
Yuan Qin Alexander R. Leydon Ann Manziello Ritu Pandey David Mount Stojan Denic Bane Vasic Mark A. Johnson Ravishankar Palanivelu 《PLoS genetics》2009,5(8)
9.
J. Bobek 《Biologia Plantarum》1971,13(5-6):405-407
Excised anthers ofNicotiana tabacum L. were culturedin vitro at the stage of pollen tetrads, which proved in our experiments to be the most suitable initial stage for cultivation, up to the stage of mature pollen grains, using Ito and Stern's nutrient medium, or this medium supplemented with uracil. Germinating capacity of the pollen grains formed and the lengths of pollen tubes were quantitatively evaluated. 相似文献
10.
11.
12.
Invertases of Lilium Pollen : Characterization and Activity during In Vitro Germination 总被引:1,自引:1,他引:0
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Two different forms of invertase are found in pollen of lily (Lilium auratum). One form is cytoplasmic (Invertase 1) and the other is bound to the pollen wall (Invertase 2). Invertase 1 has been partially purified and is a glycoprotein (apparent molecular weight, 450 kilodaltons) with a Km of 0.65 millimolar for sucrose. The two invertases differ in pH optimum and thermal stability. Invertases of lily pollen are β-fructofuranosidases which can hydrolyze sucrose but not melizitose. The mature pollen grains have enzyme activity in both cytoplasmic and wall fractions, and no increase in the activity of either occurs during germination. The wall-bound enzyme could not be released by treatments with detergents or high salt concentrations. 相似文献
13.
应用荧光显微技术、激光共聚焦扫描显微技术、单克隆抗体免疫荧光标记技术以及傅里叶变换显微红外光谱分析(FTIR)等手段,研究了内钙拮抗剂TMB-8对白皮松花粉管胞内Ca2+分布、花粉管生长以及细胞肇构建等的影响.结果表明,白皮松花粉管经TMB-8处理后,胞内的Ca2+浓度下降,花粉管内典型的Ca2+浓度梯度消失,花粉萌发... 相似文献
14.
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. 相似文献
15.
Cellulose is an important component of cell wall, yet its location and function in pollen tubes remain speculative. In this paper, we studied the role of cellulose synthesis in pollen tube elongation in Pinus bungeana Zucc. by using the specific inhibitor, 2, 6-dichlorobenzonitrile (DCB). In the presence of DCB, the growth rate and morphology of pollen tubes were distinctly changed. The organization of cytoskeleton and vesicle trafficking were also disturbed. Ultrastructure of pollen tubes treated with DCB was characterized by the loose tube wall and damaged organelles. DCB treatment induced distinct changes in tube wall components. Fluorescence labeling results showed that callose, and acidic pectin accumulated in the tip regions, whereas there was less cellulose when treated with DCB. These results were confirmed by FTIR microspectroscopic analysis. In summary, our findings showed that inhibition of cellulose synthesis by DCB affected the organization of cytoskeleton and vesicle trafficking in pollen tubes, and induced changes in the tube wall chemical composition in a dose-dependent manner. These results confirm that cellulose is involved in the establishment of growth direction of pollen tubes, and plays important role in the cell wall construction during pollen tube development despite its lower quantity. 相似文献
16.
V. A. M. Stevens B. G. Murray 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1982,61(3):245-256
Summary In Primula obconica, a species with a heteromorphic self-incompatibility system, the distinction between compatible and incompatible pollen tubes takes place on the stigma surface in thrum flowers, self tubes growing randomly over the papillar cells. No differences were seen between self and cross tube behaviour on the pin stigma surface, but self tubes were inhibited within the stigmatic tissue with differences in tube length evident after 24 h. The stigma surface bears a proteinaceous pellicle and binds the lectin Concanavalin A. Removal of the stigma removes the incompatibility barrier in mature gynoecia. Bud pollination shows that pollen tubes cannot grow in a normal manner on immature stigmas; the random growth of tubes over the stigma surface resembles that of mature thrum selfs. Fewer compatible tubes reach the style base of young gynoecia and smaller numbers of seeds are set than in mature flowers. Pin and thrum pollen grains germinate and grow in aqueous media, thrum tubes growing longer than pin. The presence of H3BO4 and CaCl2 in the growth medium promotes tube elongation and lengths equivalent to compatible styles can be obtained. The pollen grains have proteinaceous materials in their walls which diffuse out on moistening. Prolonged washing in aqueous media removes these materials but the incompatibility reaction remains unchanged. Thus the incompatibility reaction is between pollen tubes and stigmatic tissue and differs from the homomorphic, sporophytic system where pollen wall proteins elicit the incompatibility response. 相似文献
17.
Directional Guidance of Nicotiana alata
Pollen Tubes
in Vitro and on the Stigma 总被引:2,自引:0,他引:2
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Pollen tubes navigate the route from stigma to ovule with great accuracy, but the cues that guide them along this route are not known. We reproduced the environment on the stigma of Nicotiana alata by immersing pollen in stigma exudate or oil close to an interface with an aqueous medium. The growth of pollen in this culture system mimicked growth on stigmas: pollen grains hydrated and germinated, and pollen tubes grew toward the aqueous medium. The rate-limiting step in pollen germination was the movement of water through the surrounding exudate or oil. By elimination of other potential guidance cues, we conclude that the directional supply of water probably determined the axis of polarity of pollen tubes and resulted in growth toward the interface. We propose that a gradient of water in exudate is a guidance cue for pollen tubes on the stigma and that the composition of the exudate must be such that it is permeable enough for pollen hydration to occur but not so permeable that the supply of water becomes nondirectional. Pollen tube penetration of the stigma may be the most frequently occurring hydrotropic response of higher plants. 相似文献
18.
Fernando DD 《Proteomics》2005,5(18):4917-4926
The differentially expressed proteins in pollen tubes indicate their specific roles in this stage of male gametophyte development. To isolate these proteins, 2-DE was done using ungerminated pollen and 2-day-old pollen tubes of Pinus strobus. Results show that 645 and 647 protein spots were clearly resolved from pollen grains and pollen tubes, respectively. Thirty-eight protein spots were expressed only in pollen tubes, while 19 increased in intensity. MALDI-TOF MS was used to generate tryptic peptide masses that were submitted to Mascot for identification. Of the differentially expressed proteins, 12% matched with hypothetical proteins, 33% did not hit any protein, and for the 55%, a putative function was assigned based on similarity of sequences with previously characterized proteins. Therefore, pollen tube development can be characterized by the cellular activities that involve metabolism, stress/defense response, gene regulation, signal transduction, and cell wall formation. This study expands our understanding of the changes in protein expression associated with pollen tube development and provides insights into the molecular programs that separate the development of the pollen tubes from pollen grains. This is the first report that describes a global analysis of differentially expressed proteins from the pollen tube of any seed plant. 相似文献
19.
Growth and development of conifer pollen tubes 总被引:1,自引:0,他引:1
Conifer pollen tubes are an important but underused experimental system in plant biology. They represent a major evolutionary
step in male gametophyte development as an intermediate form between the haustorial pollen tubes of cycads and Ginkgo and the structurally reduced and faster growing pollen tubes of flowering plants. Conifer pollen grains are available in
large quantities, most can be stored for several years, and they grow very well in culture. The study of pollen tube growth
and development furthers our understanding of conifer reproduction and contributes towards our ability to improve on their
productivity. This review covers taxonomy and morphology to cell, developmental, and molecular biology. It explores recent
advances in research on conifer pollen and pollen tubes in vivo, focusing on pollen wall structure, male gametophyte development
within the pollen wall, pollination mechanisms, pollen tube growth and development, and programmed cell death. It also explores
recent research in vitro, including the cellular mechanisms underlying pollen tube elongation, in vitro fertilization, genetic
transformation and gene expression, and pine pollen tube proteomics. With the ongoing sequencing of the Pinus taeda genome in several labs, we expect the use of conifer pollen tubes as an experimental system to increase in the next decade. 相似文献
20.
Pollen tube growth is essential for the fertilization process in angiosperms. When pollen grains arrive on the stigma, they germinate, and the pollen tubes elongate through the styles of the pistils to deliver sperm cells into the ovules to produce the seeds. The relationship between the growth rate and style length remains unclear. In previous studies, we developed a liquid pollen germination medium for observing pollen tube growth. In this study, using this medium, we examined the pollen tube growth ability in Petunia axillaris subsp. axillaris, P. axillaris subsp. parodii, P. integrifolia, and P. occidentalis, which have different style lengths. Petunia occidentalis had the longest pollen tubes after 6 h of culture but had a relatively shorter style. Conversely, the pollination experiments revealed that P. axillaris subsp. parodii, which had the longest style, produced the longest pollen tubes in vivo. The results revealed no clear relationship between the style lengths and the growth rate of pollen tubes in vitro. Interspecific pollinations indicated that the styles affected pollen tube growth. We concluded that, in vitro, the pollen tubes grow without being affected by the styles, whereas, in vivo, the styles significantly affected pollen tube growth. Furthermore, interspecific pollination experiments implied that the pollen tube growth tended to be suppressed in the styles of self-incompatibility species. Finally, we discussed the pollen tube growth ability in relation to style lengths. 相似文献