scholarly journals Uncoupling secretion and tip growth in lily pollen tubes: evidence for the role of calcium in exocytosis

1999 ◽  
Vol 19 (4) ◽  
pp. 379-386 ◽  
Author(s):  
Stephane J. Roy ◽  
Terena L. Holdaway-Clarke ◽  
Grant R. Hackett ◽  
Joseph G. Kunkel ◽  
Elizabeth M. Lord ◽  
...  
Keyword(s):  
Tip Growth ◽  
Pollen Tubes ◽  
Lily Pollen

scholarly journals Nifedipine-sensitive calcium channels are involved in polar growth of lily pollen tubes

1985 ◽  
Vol 76 (1) ◽  
pp. 247-254
Author(s):  
H.D. Reiss ◽  
W. Herth
Keyword(s):  
Calcium Channels ◽  
Tip Growth ◽  
Lilium Longiflorum ◽  
Pollen Tubes ◽  
Polar Growth ◽  
Treatment Results ◽  
High Tendency ◽  
Lily Pollen ◽  
Internal Calcium

Pollen germination and tube growth of Lilium longiflorum in vitro are affected by 10(−5) M-nifedipine. Germinating ‘tubes’ form broad protuberances along the whole colpus. Short tubes show a high tendency to grow ‘amoeboid-like’ and to branch; or a second tube emerges in another region of the colpus. Longer tubes (greater than or equal to 100 micron) broaden irregularly or swell at their tips. The diameter of the tube can vary drastically within the same tube. With increasing time of treatment many tubes burst. Normal tip growth stops within 10 min, but protoplasmic streaming continues even after 15 h. More or less regularly, wall thickenings are formed along the whole tube or on the flanks of the germinating region after some hours. The internal calcium gradient, visualized by chlorotetracycline (CTC) fluorescence, is also disturbed. Nifedipine treatment results in uniform or irregular CTC fluorescence. Branching tubes temporarily show a new subapical CTC gradient. After 6–8 h of nifedipine treatment many cells are no longer stainable with CTC. The results indicate the presence of nifedipine-sensitive calcium channels in pollen tubes.

scholarly journals Protein Analysis of Pollen Tubes after the Treatments of Membrane Trafficking Inhibitors Gains Insights on Molecular Mechanism Underlying Pollen Tube Polar Growth

2021 ◽  
Vol 40 (2) ◽  
pp. 205-222
Author(s):  
Monica Scali ◽  
Alessandra Moscatelli ◽  
Luca Bini ◽  
Elisabetta Onelli ◽  
Rita Vignani ◽  
...  
Keyword(s):  
Pollen Tube ◽  
Actin Cytoskeleton ◽  
Membrane Trafficking ◽  
Tip Growth ◽  
Male Gametophyte ◽  
Pollen Tubes ◽  
Structural Features ◽  
Two Dimensional Gel Electrophoresis ◽  
Depth Analysis

AbstractPollen tube elongation is characterized by a highly-polarized tip growth process dependent on an efficient vesicular transport system and largely mobilized by actin cytoskeleton. Pollen tubes are an ideal model system to study exocytosis, endocytosis, membrane recycling, and signaling network coordinating cellular processes, structural organization and vesicular trafficking activities required for tip growth. Proteomic analysis was applied to identifyNicotiana tabacumDifferentially Abundant Proteins (DAPs) after in vitro pollen tube treatment with membrane trafficking inhibitors Brefeldin A, Ikarugamycin and Wortmannin. Among roughly 360 proteins separated in two-dimensional gel electrophoresis, a total of 40 spots visibly changing between treated and control samples were identified by MALDI-TOF MS and LC–ESI–MS/MS analysis. The identified proteins were classified according to biological processes, and most proteins were related to pollen tube energy metabolism, including ammino acid synthesis and lipid metabolism, structural features of pollen tube growth as well modification and actin cytoskeleton organization, stress response, and protein degradation. In-depth analysis of proteins corresponding to energy-related pathways revealed the male gametophyte to be a reliable model of energy reservoir and dynamics.

Tip growth in pollen tubes: calcium leads the way

1997 ◽  
Vol 2 (3) ◽  
pp. 79-80 ◽  
Author(s):  
Peter K. Hepler
Keyword(s):  
Tip Growth ◽  
Pollen Tubes ◽  
The Way

Pronounced cytoplasmic pH gradients are not required for tip growth in plant and fungal cells

1997 ◽  
Vol 110 (10) ◽  
pp. 1187-1198 ◽  
Author(s):  
R.M. Parton ◽  
S. Fischer ◽  
R. Malho ◽  
O. Papasouliotis ◽  
T.C. Jelitto ◽  
...  
Keyword(s):  
Tip Growth ◽  
Cell Types ◽  
Pollen Tubes ◽  
Fine Tuning ◽  
Cytoplasmic Ph ◽  
Dual Emission ◽  
Ph Gradients ◽  
Longitudinal Gradients ◽  
External Ph

The existence of pronounced cytoplasmic pH gradients within the apices of tip-growing cells, and the role of cytoplasmic pH in regulating tip growth, were investigated in three different cell types: vegetative hyphae of Neurospora crassa; pollen tubes of Agapanthus umbellatus; and rhizoids of Dryopteris affinis gametophytes. Examination of cytoplasmic pH in growing cells was performed by simultaneous, dual emission confocal ratio imaging of the pH-sensitive probe carboxy SNARF-1. Considerable attention was paid to the fine tuning of dye loading and imaging parameters to minimise cellular perturbation and assess the extent of dye partitioning into organelles. With optimal conditions, cytoplasmic pH was measured routinely with a precision of between +/−0.03 and +/−0.06 of a pH unit and a spatial resolution of 2.3 microm2. Based on in vitro calibration, estimated values of mean cytoplasmic pH for cells loaded with dye-ester were between 7.15 and 7.25 for the three cell types. After pressure injecting Neurospora hyphae with dextran-conjugated dye, however, the mean cytoplasmic pH was estimated to be 7.57. Dextran dyes are believed to give a better estimate of cytoplasmic pH because of their superior localisation and retention within the cytosol. No significant cytoplasmic pH gradient (delta pH of >0.1 unit) was observed within the apical 50 microm in growing cells of any of the three cell types. Acidification or alkalinisation of the cytoplasm in Neurospora hyphae, using a cell permeant weak acid (propionic acid at pH 7.0) or weak base (trimethylamine at pH 8.0), slowed down but did not abolish growth. However, similar manipulation of the cytoplasmic pH of Agapanthus pollen tubes and Dryopteris rhizoids completely inhibited growth. Modification of external pH affected the growth pattern of all cell types. In hyphae and pollen tubes, changes in external pH were found to have a small transient effect on cytoplasmic pH but the cells rapidly readjusted towards their original pH. Our results suggest that pronounced longitudinal gradients in cytoplasmic pH are not essential for the regulation of tip growth.

DIACYLGLYCEROL KINASE 5 regulates polar tip growth of tobacco pollen tubes

2021 ◽  
Author(s):  
Patricia Scholz ◽  
Přemysl Pejchar ◽  
Max Fernkorn ◽  
Eliška Škrabálková ◽  
Roman Pleskot ◽  
...  
Keyword(s):  
Tip Growth ◽  
Diacylglycerol Kinase ◽  
Pollen Tubes ◽  
Tobacco Pollen ◽  
Polar Tip Growth

Morphology of Cell Injury: An Approach to the EDIT Programme by the Use of Tobacco Pollen Tubes

2002 ◽  
Vol 30 (3) ◽  
pp. 323-329 ◽  
Author(s):  
Udo Kristen ◽  
Natalie Bischoff ◽  
Saskia Lisboa ◽  
Enno Schirmer ◽  
Sören Witt ◽  
...  
Keyword(s):  
Tip Growth ◽  
Cell Injury ◽  
Cytosolic Calcium ◽  
Pollen Tubes ◽  
In Vitro Cytotoxicity ◽  
Toxic Compounds ◽  
In Vitro System ◽  
Tobacco Pollen ◽  
Different Types

Tobacco pollen tubes were used as a standard in vitro system to investigate cell growth aberrations caused by some of the Multicentre Evaluation of In Vitro Cytotoxicity (MEIC) programme chemicals and other toxic compounds. Changes in cytoskeletal pattern were observed in the tube cells by using tubu-lin immunofluorescence and rhodamin–phalloidin fluorescence for the localisation of microtubules and actin filaments, respectively. Four different types of cell malformation were found: screw-like growth, isodiametric tip swelling, hook formation, and pollen grain enlargement. We suggest that these malformations resulted from an interference by the chemicals with the cytosolic calcium gradient which controls tip growth and the orientation of the pollen tube. The results may contribute to a general understanding of toxicity-based cell malformations.

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