Dynamics of the apical vesicle accumulation and the rate of growth are related in individual pollen tubes

2001 ◽  
Vol 114 (14) ◽  
pp. 2685-2695 ◽  
Author(s):  
R. M. Parton ◽  
S. Fischer-Parton ◽  
M. K. Watahiki ◽  
A. J. Trewavas
Keyword(s):  
Growth Rate ◽  
Plasma Membrane ◽  
Pollen Tube ◽  
Staining Pattern ◽  
Periodic Oscillation ◽  
Quantitative Relationship ◽  
Pollen Tubes ◽  
Apical Region ◽  
Secretory Vesicles ◽  
Animal Cells

Regulated secretory vesicle delivery, vesicle fusion and rapid membrane recycling are all contentious issues with respect to tip growth in plant, fungal and animal cells. To examine the organisation and dynamics of membrane movements at the growing pollen tube apex and address the question of their relationship to growth, we have used the membrane stain FM4-64 both as a structural marker and as a quantitative assay. Labelling of living Lilium Longiflorum pollen tubes by FM4-64 resulted in a distinct staining pattern in the tube apex, which corresponds spatially to the previously identified cone-shaped `apical clear zone' containing secretory vesicles. Dye uptake could be inhibited by sodium azide and followed a strict temporal sequence from the plasma membrane to a population of small (1-2 μm diameter) discrete internal structures, with subsequent appearance of dye in the apical region and ultimately in vacuolar membranes. Washout of the dye rapidly removed the plasma membrane staining, which was followed by a gradual decline in the apical fluorescence over more than an hour. Injected aqueous FM4-64 solution showed a relatively even distribution within the pollen tube. Association of FM4-64 with apical secretory vesicles was supported by the effects of the inhibitors Brefeldin-A and Cytochalasin-D, which are known to affect the localisation and number of such vesicles, on the FM4-64 staining pattern. Examination of the dynamics of FM4-64 labelling in the pollen tube tip by time-lapse observation, supported by fluorescence-recovery-after-photobleaching (FRAP) analysis, suggested the possibility of distinct pathways of bulk membrane movement both towards and, significantly, away from the apex. Quantitative analysis of FM4-64 distribution in the apex revealed that fluctuations in fluorescence 5 to 10 μm subapically, and to a lesser extent the apical 3 μm, could be related to the periodic oscillation in pollen tube growth rate. This data reveals a quantitative relationship between FM4-64 staining and growth rate within an individual tube.

scholarly journals Persistent directional growth capability in Arabidopsis thaliana pollen tubes after nuclear elimination from the apex

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Kazuki Motomura ◽  
Hidenori Takeuchi ◽  
Michitaka Notaguchi ◽  
Haruna Tsuchi ◽  
Atsushi Takeda ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Pollen Tube ◽  
Sperm Cell ◽  
Pollen Tubes ◽  
Vegetative Nucleus ◽  
Sperm Cells ◽  
Apical Region ◽  
Basal Region ◽  
Specific Expression ◽  
Directional Growth

AbstractDuring the double fertilization process, pollen tubes deliver two sperm cells to an ovule containing the female gametes. In the pollen tube, the vegetative nucleus and sperm cells move together to the apical region where the vegetative nucleus is thought to play a crucial role in controlling the direction and growth of the pollen tube. Here, we report the generation of pollen tubes in Arabidopsis thaliana whose vegetative nucleus and sperm cells are isolated and sealed by callose plugs in the basal region due to apical transport defects induced by mutations in the WPP domain-interacting tail-anchored proteins (WITs) and sperm cell-specific expression of a dominant mutant of the CALLOSE SYNTHASE 3 protein. Through pollen-tube guidance assays, we show that the physiologically anuclear mutant pollen tubes maintain the ability to grow and enter ovules. Our findings provide insight into the sperm cell delivery mechanism and illustrate the independence of the tip-localized vegetative nucleus from directional growth control of the pollen tube.

scholarly journals The Neurospora crassa exocyst complex tethers Spitzenkörper vesicles to the apical plasma membrane during polarized growth

2014 ◽  
Vol 25 (8) ◽  
pp. 1312-1326 ◽  
Author(s):  
Meritxell Riquelme ◽  
Erin L. Bredeweg ◽  
Olga Callejas-Negrete ◽  
Robert W. Roberson ◽  
Sarah Ludwig ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Neurospora Crassa ◽  
Hyphal Growth ◽  
Apical Plasma Membrane ◽  
Apical Region ◽  
Secretory Vesicles ◽  
Polarized Growth ◽  
Hyphal Morphogenesis ◽  
Exocyst Complex ◽  
Dynamic Formation

Fungal hyphae are among the most highly polarized cells. Hyphal polarized growth is supported by tip-directed transport of secretory vesicles, which accumulate temporarily in a stratified manner in an apical vesicle cluster, the Spitzenkörper. The exocyst complex is required for tethering of secretory vesicles to the apical plasma membrane. We determined that the presence of an octameric exocyst complex is required for the formation of a functional Spitzenkörper and maintenance of regular hyphal growth in Neurospora crassa. Two distinct localization patterns of exocyst subunits at the hyphal tip suggest the dynamic formation of two assemblies. The EXO-70/EXO-84 subunits are found at the peripheral part of the Spitzenkörper, which partially coincides with the outer macrovesicular layer, whereas exocyst components SEC-5, -6, -8, and -15 form a delimited crescent at the apical plasma membrane. Localization of SEC-6 and EXO-70 to the plasma membrane and the Spitzenkörper, respectively, depends on actin and microtubule cytoskeletons. The apical region of exocyst-mediated vesicle fusion, elucidated by the plasma membrane–associated exocyst subunits, indicates the presence of an exocytotic gradient with a tip-high maximum that dissipates gradually toward the subapex, confirming the earlier predictions of the vesicle supply center model for hyphal morphogenesis.

scholarly journals Essential function of Drosophila Sec6 in apical exocytosis of epithelial photoreceptor cells

2005 ◽  
Vol 169 (4) ◽  
pp. 635-646 ◽  
Author(s):  
Slobodan Beronja ◽  
Patrick Laprise ◽  
Ophelia Papoulas ◽  
Milena Pellikka ◽  
John Sisson ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Protein Transport ◽  
Basolateral Membrane ◽  
Photoreceptor Cells ◽  
Secretory Vesicles ◽  
Membrane Domains ◽  
Animal Cells ◽  
Light Sensing ◽  
Membrane Growth ◽  
Essential Function

Polarized exocytosis plays a major role in development and cell differentiation but the mechanisms that target exocytosis to specific membrane domains in animal cells are still poorly understood. We characterized Drosophila Sec6, a component of the exocyst complex that is believed to tether secretory vesicles to specific plasma membrane sites. sec6 mutations cause cell lethality and disrupt plasma membrane growth. In developing photoreceptor cells (PRCs), Sec6 but not Sec5 or Sec8 shows accumulation at adherens junctions. In late PRCs, Sec6, Sec5, and Sec8 colocalize at the rhabdomere, the light sensing subdomain of the apical membrane. PRCs with reduced Sec6 function accumulate secretory vesicles and fail to transport proteins to the rhabdomere, but show normal localization of proteins to the apical stalk membrane and the basolateral membrane. Furthermore, we show that Rab11 forms a complex with Sec5 and that Sec5 interacts with Sec6 suggesting that the exocyst is a Rab11 effector that facilitates protein transport to the apical rhabdomere in Drosophila PRCs.

scholarly journals Assessment of self-(in) compatibility in some sweet cherry (Prunus avium L.) genotypes

Genetika ◽  
2013 ◽  
Vol 45 (3) ◽  
pp. 939-952 ◽  
Author(s):  
Sanja Radicevic ◽  
Sladjana Maric ◽  
Radosav Cerovic ◽  
Milena Djordjevic
Keyword(s):  
Growth Rate ◽  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Sweet Cherry ◽  
Prunus Avium ◽  
Fruit Set ◽  
Pollen Tubes ◽  
Pollen Tube Growth Rate ◽  
Prunus Avium L

The paper presents results of a three-year study of self-(in)compatibility in four economically important sweet cherry genotypes - ?Karina?, ?Kordia?, ?Regina? and ?Summit?, under agro-environmental conditions of Western Serbia. Determination of S-RNase genotype, microscopic observation of the pollen tube growth rate and assaying of the fruit set level after self-pollination were used to assess the genotypes. ?Kordia? (S3S6), ?Regina? (S1S3) and ?Summit? (S1S2) are self-incompatible genotypes, with a considerable number of pollen tubes ending the growth in the middle third of the style and lack of fruit set. ?Karina?, as S3S4 genotype, behaved as self-compatible, since its pollen tubes reached the base of the style and ovary, penetrating the nucellus. In addition, fruit set for ?Karina? was recorded in all three years of study (40.26%, 18.79% and 21.81%, respectively).

scholarly journals Self-incompatibility in Cornus florida

HortScience ◽  
2004 ◽  
Vol 39 (2) ◽  
pp. 335-338 ◽  
Author(s):  
Sandra M. Reed
Keyword(s):  
Growth Rate ◽  
Pollen Tube ◽  
Pollen Tube Growth ◽  
Seed Set ◽  
Pollen Tubes ◽  
Cornus Florida ◽  
Self Incompatibility ◽  
Flowering Dogwood ◽  
Pollen Tube Growth Rate ◽  
Upper Third

Low seed set has been reported following self-pollinations of flowering dogwood (Cornus florida L.). The objective of this study was to verify the presence of self-incompatibility in C. florida. `Cherokee Princess' stigmas and styles were collected 1, 2, 4, 8, 12, 24, 48, and 72 hours after cross- and self-pollinations, stained with aniline blue and observed using a fluorescence microscope. Pollen germinated freely following self-pollinations, but self-pollen tubes grew slower than those resulting from cross-pollinations. By 48 hours after cross-pollination, pollen tubes had reached the bottom of the style while pollen tubes in self-pollinated flowers had only penetrated the upper third of the style. Evidence of reduced pollen tube growth rate in self-pollinations of `Cherokee Chief' and `Cherokee Brave' was also obtained. This study provides evidence of a gametophytic self-incompatibity system in C. florida. It was also determined that stigmas of C. florida `Cherokee Princess' are receptive to pollen from 1 day prior to anthesis to 1 day after anthesis.

scholarly journals Microtubules play a role in trafficking prevacuolar compartments to vacuoles in tobacco pollen tubes

Open Biology ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 180078 ◽  
Author(s):  
Elisabetta Onelli ◽  
Monica Scali ◽  
Marco Caccianiga ◽  
Nadia Stroppa ◽  
Piero Morandini ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Pollen Tube ◽  
Biochemical Analysis ◽  
Pollen Tubes ◽  
Degradation Pathways ◽  
Transient Transformation ◽  
Secretory Pathways ◽  
Tobacco Pollen ◽  
Fine Regulation ◽  
Pollen Tube Elongation

Fine regulation of exocytosis and endocytosis plays a basic role in pollen tube growth. Excess plasma membrane secreted during pollen tube elongation is known to be retrieved by endocytosis and partially reused in secretory pathways through the Golgi apparatus. Dissection of endocytosis has enabled distinct degradation pathways to be identified in tobacco pollen tubes and has shown that microtubules influence the transport of plasma membrane internalized in the tip region to vacuoles. Here, we used different drugs affecting the polymerization state of microtubules together with SYP21, a marker of prevacuolar compartments, to characterize trafficking of prevacuolar compartments in Nicotiana tabacum pollen tubes. Ultrastructural and biochemical analysis showed that microtubules bind SYP21-positive microsomes. Transient transformation of pollen tubes with LAT52-YFP-SYP21 revealed that microtubules play a key role in the delivery of prevacuolar compartments to tubular vacuoles.

scholarly journals Apple Pollen Tube Growth Rates Are Regulated by Parentage and Environment

2016 ◽  
Vol 141 (6) ◽  
pp. 548-554 ◽  
Author(s):  
Candace N. DeLong ◽  
Keith S. Yoder ◽  
Leon Combs ◽  
Richard E. Veilleux ◽  
Gregory M. Peck
Keyword(s):  
Growth Rate ◽  
Pollen Tube ◽  
Growth Rates ◽  
Pollen Tube Growth ◽  
Management Strategies ◽  
Pollen Tubes ◽  
Tube Growth ◽  
Load Management ◽  
Crop Load ◽  
Pollen Tube Growth Rate

A greater understanding of apple (Malus ×domestica) pollen tube growth rates can improve crop load management in commercial orchards. Specifically, applications of caustic bloom-thinning chemicals need to occur when enough, but not too many, flowers have been fertilized to achieve crop load densities that balance yields with marketable fruit sizes. In this study, the pollen tube growth rates of five crabapple (Malus sp.) cultivars were measured in the styles of three maternal cultivars at 12, 18, 24, and 30 °C after 24 hours in a growth chamber. Pollen tube growth rates were greatest for ‘Selkirk’ and ‘Thunderchild’ at 12 °C, and greatest for ‘Indian Summer’, ‘Selkirk’, and ‘Thunderchild’ at 24 °C. Pollen tube growth increased with increasing temperatures until 24 °C. There were minimal pollen tube growth rate increases between 24 and 30 °C. Overall, ‘Snowdrift’ had the slowest pollen tube growth rate of the five evaluated crabapple genotypes. At 24 and 30 °C, ‘Indian Summer’ and ‘Thunderchild’ pollen tubes reached the base of the style most frequently, and ‘Snowdrift’ pollen tubes the least frequently. Pollen tube growth rate was also influenced by the maternal cultivar, with Golden Delicious having relatively faster pollen tube growth than Fuji at 24 and 30 °C. Interactions among paternal and maternal genotypes as well as temperature after pollination reveal complex biological and environmental relationships that can be used to develop more precise crop load management strategies for apple orchards.

Confocal image analysis of spatial variations in immunocytochemically identified calmodulin during pollen hydration, germination and pollen tube tip growth in Nicotiana tabacum L.

Zygote ◽  
1994 ◽  
Vol 2 (1) ◽  
pp. 63-68 ◽  
Author(s):  
Uday K. Tirlapur ◽  
Monica Scali ◽  
Alessandra Moscatelli ◽  
Cecilia Del Casino ◽  
Gianpiero Cai ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Nicotiana Tabacum ◽  
Pollen Tube ◽  
Pollen Tubes ◽  
Spatial Variations ◽  
Tube Growth ◽  
Confocal Scanning Laser Microscopy ◽  
Pollen Hydration ◽  
Confocal Scanning Laser ◽  
High Level

SummaryUsing monoclonal anti-calmodulin antibodies in conjunction with confocal scanning laser microscopy we have analysed the spatial variations in the distribution pattern of calmodulin (CaM) during the sequential events of pollen hydration, germination and tube growth in Nicotiana tabacum. These immunocytochemical observations have been complemented by immunochemical studies wherein the anti-calmodulin antibody raised against pea CaM recognises a polypeptide of c. 18 kDa in the pollen extracts. Digitisation of confocally acquired optical sections of immunofluorescence images reveals that in hydrated pollen a high level of CaM is consistently present in the region of the germinal apertures. Subsequently, with the onset of germination a high CaM concentration was found associated with the plasma membrane of the germination bubble and in the cytoplasm in its vicinity, while in the vegetative cytoplasm a weak diffuse and intense punctate signal was registered. CaM immunostain was also detected in association with the plasma membrane of the tube tips in both short and long pollen tubes. Furthermore, the cytosol of the tubes invariably manifested an apically focused CaM gradient. We were, however, unable to detect any vacuolar association of CaM in the older regions of the pollen tubes. Although punctate immunostain was obvious across the pollen tube numerous punctate structures were invariably present in the extreme tip. The possible implications of these findings in development of cell polarity, polarised growth, maintenance of calcium homeostasis and CaM interactions with other mechanochemical motor proteins in effecting propulsion of organelles during pollen hydration, germination and pollen tube growth are discussed.

scholarly journals Unequal Growth Rate of Pollen Tubes from Normal and Stringless Pea Genotypes

HortScience ◽  
1992 ◽  
Vol 27 (7) ◽  
pp. 833-834 ◽  
Author(s):  
Rebecca J. McGee ◽  
James R. Baggett
Keyword(s):  
Growth Rate ◽  
Pisum Sativum ◽  
Pollen Tube ◽  
Time Course ◽  
Pollen Tubes ◽  
In Vitro Germination ◽  
Pollen Tube Growth Rate ◽  
Germination Of Pollen

There was no difference in percentage in vitro germination of pollen from stringless pea (Pisum sativum L.) cv. Sugar Daddy and stringy `Oregon Sugarpod II' (OSP) and `OSU 705' (705). However, pollen tubes of `Sugar Daddy' grew more slowly in vitro than those of OSP or 705. Differences in pollen tube growth rate were demonstrated in vivo following time-course pollinations involving reciprocal crosses of `Sugar Daddy' with OSP and 705, along with the selfed parents. After 8 hours, pollen tubes from stringless peas (“stringless” pollen) had entered 13% of the ovules compared with 51% for those from stringy peas (“stringy” pollen). Stringless pollen tubes entered 29% and stringy pollen tubes 66% of the ovules after 10 hours. The slower growth of stringless compared with stringy pollen tubes is a plausible explanation for previously observed deficiencies of stringless plants in segregating populations.

scholarly journals Coordinated Localization and Antagonistic Function of NtPLC3 and PI4P 5-Kinases in the Subapical Plasma Membrane of Tobacco Pollen Tubes

Plants ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 452 ◽  
Author(s):  
Irene Stenzel ◽  
Till Ischebeck ◽  
Linh Hai Vu-Becker ◽  
Mara Riechmann ◽  
Praveen Krishnamoorthy ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Pollen Tube ◽  
Tip Growth ◽  
Pollen Tubes ◽  
Dominant Negative ◽  
Membrane Domains ◽  
Tobacco Pollen ◽  
Polar Tip Growth ◽  
Spinning Disc

Polar tip growth of pollen tubes is regulated by the membrane phospholipid phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2), which localizes in a well-defined region of the subapical plasma membrane. How the PtdIns(4,5)P2 region is maintained is currently unclear. In principle, the formation of PtdIns(4,5)P2 by PI4P 5-kinases can be counteracted by phospholipase C (PLC), which hydrolyzes PtdIns(4,5)P2. Here, we show that fluorescence-tagged tobacco NtPLC3 displays a subapical plasma membrane distribution which frames that of fluorescence-tagged PI4P 5-kinases, suggesting that NtPLC3 may modulate PtdIns(4,5)P2-mediated processes in pollen tubes. The expression of a dominant negative NtPLC3 variant resulted in pollen tube tip swelling, consistent with a delimiting effect on PtdIns(4,5)P2 production. When pollen tube morphologies were assessed as a quantitative read-out for PtdIns(4,5)P2 function, NtPLC3 reverted the effects of a coexpressed PI4P 5-kinase, demonstrating that NtPLC3-mediated breakdown of PtdIns(4,5)P2 antagonizes the effects of PtdIns(4,5)P2 overproduction in vivo. When analyzed by spinning disc microscopy, fluorescence-tagged NtPLC3 displayed discontinuous membrane distribution omitting punctate areas of the membrane, suggesting that NtPLC3 is involved in the spatial restriction of plasma membrane domains also at the nanodomain scale. Together, the data indicate that NtPLC3 may contribute to the spatial restriction of PtdIns(4,5)P2 in the subapical plasma membrane of pollen tubes.

Sign in / Sign up

Export Citation Format

Share Document