Document Detail

Oscillatory chloride efflux at the pollen tube apex has a role in growth and cell volume regulation and is targeted by inositol 3,4,5,6-tetrakisphosphate.
MedLine Citation:
PMID:  12215517     Owner:  NLM     Status:  MEDLINE    
Oscillatory growth of pollen tubes has been correlated with oscillatory influxes of the cations Ca(2+), H(+), and K(+). Using an ion-specific vibrating probe, a new circuit was identified that involves oscillatory efflux of the anion Cl(-) at the apex and steady influx along the tube starting at 12 microm distal to the tip. This spatial coupling of influx and efflux sites predicts that a vectorial flux of Cl(-) ion traverses the apical region. The Cl(-) channel blockers 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS) and 5-nitro-2-(3-phenylpropylamino)benzoic acid completely inhibited tobacco pollen tube growth at 80 and 20 microM, respectively. Cl(-) channel blockers also induced increases in apical cell volume. The apical 50 micro m of untreated pollen tubes had a mean cell volume of 3905 +/- 75 microm(3). DIDS at 80 microM caused a rapid and lethal cell volume increase to 6206 +/- 171 microm(3), which is at the point of cell bursting at the apex. DIDS was further demonstrated to disrupt Cl(-) efflux from the apex, indicating that Cl(-) flux correlates with pollen tube growth and cell volume status. The signal encoded by inositol 3,4,5,6-tetrakisphosphate [Ins(3,4,5,6)P(4)] antagonized pollen tube growth, induced cell volume increases, and disrupted Cl(-) efflux. Ins(3,4,5,6)P(4) decreased the mean growth rate by 85%, increased the cell volume to 5997 +/- 148 microm(3), and disrupted normal Cl(-) efflux oscillations. These effects were specific for Ins(3,4,5,6)P(4) and were not mimicked by either Ins(1,3,4,5)P(4) or Ins(1,3,4,5,6)P(5). Growth correlation analysis demonstrated that cycles of Cl(-) efflux were coupled to and temporally in phase with cycles of growth. A role for Cl(-) flux in the dynamic cellular events during growth is assessed. Differential interference contrast microscopy and kymographic analysis of individual growth cycles revealed that vesicles can advance transiently to within 2 to 4 microm of the apex during the phase of maximally increasing Cl(-) efflux, which temporally overlaps the phase of cell elongation during the growth cycle. In summary, these investigations indicate that Cl(-) ion dynamics are an important component in the network of events that regulate pollen tube homeostasis and growth.
Laura Zonia; Sofia Cordeiro; Jaroslav Tupý; José A Feijó
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Plant cell     Volume:  14     ISSN:  1040-4651     ISO Abbreviation:  Plant Cell     Publication Date:  2002 Sep 
Date Detail:
Created Date:  2002-09-06     Completed Date:  2002-12-27     Revised Date:  2010-09-20    
Medline Journal Info:
Nlm Unique ID:  9208688     Medline TA:  Plant Cell     Country:  United States    
Other Details:
Languages:  eng     Pagination:  2233-49     Citation Subset:  IM    
Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Na Pernikarce 15, 160 00 Prague 6, Czech Republic.
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MeSH Terms
4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid / pharmacology
Cell Division / drug effects
Cell Size / drug effects
Chloride Channels / metabolism
Chlorides / metabolism*
Inositol Phosphates / pharmacology*
Lilium / cytology,  drug effects,  growth & development
Niflumic Acid / pharmacology
Nitrobenzoates / pharmacology
Pollen / drug effects,  growth & development*,  metabolism
Tobacco / cytology,  drug effects,  growth & development
Reg. No./Substance:
0/Chloride Channels; 0/Chlorides; 0/Inositol Phosphates; 0/Nitrobenzoates; 0/inositol-1,3,4,5,6-pentakisphosphate; 102850-29-3/inositol-1,3,4,5-tetrakisphosphate; 107254-86-4/5-nitro-2-(3-phenylpropylamino)benzoic acid; 112791-61-4/inositol-3,4,5,6-tetrakisphosphate; 4394-00-7/Niflumic Acid; 53005-05-3/4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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