Transport of Cl- across the plasma membrane during pollen grain germination in tobacco.
The role of Cl- transport across the plasma membrane was studied in an early step of pollen grain germination in tobacco Nicotiana tabacum L. The Cl- channel blockers, 5-nitro-2-(3-phenylpropylamino)benzoic acid (NPPB) and niflumic acid, completely suppress the germination with IC(50) approximately 8 micro M. At this concentration NPPB reduces the rate of Cl- efflux out of pollen grain by 1.8-fold in the interval 5-12 min, and niflumic acid reduces the rate 1.2-fold. 4,4;-Diisothiocyanatostilbene-2,2;-disulfonic acid, a known inhibitor of Cl- channels and antiporters, completely suppresses germination as well (IC(50) = 240 micro M), but has no effect on the rate of Cl- efflux. Inhibitors of chloride co-transporters, such as furosemide, bumetanide, and bis(1,3-dibutylbarbituric acid)pentamethine oxonol, suppress the germination by less than 50%. This set of data suggests that NPPB-sensitive anion channels are involved in the activation of pollen grains in the early stage of germination.
Matveyeva
N P
NP
Department of Plant Physiology, Faculty of Biology, Lomonosov Moscow State University, Moscow, 119899, Russia. plantphys@biophys.msu.ru
Andreyuk
D S
DS
Yermakov
I P
IP
D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid / Q000494:pharmacology; D017920:Antiporters / Q000187:drug effects; D001463:Barbiturates / Q000494:pharmacology; D002034:Bumetanide / Q000494:pharmacology; D018118:Chloride Channels / Q000037:antagonists & inhibitors*; D005665:Furosemide / Q000494:pharmacology; D018525:Germination / Q000187:drug effects*; D017136:Ion Transport / Q000187:drug effects; D007555:Isoxazoles / Q000494:pharmacology; D009544:Niflumic Acid / Q000494:pharmacology; D009579:Nitrobenzoates / Q000494:pharmacology; D011058:Pollen / Q000502:physiology*; D014026:Nicotiana / Q000502:physiology*
D017920:Antiporters; D001463:Barbiturates; D018118:Chloride Channels; D007555:Isoxazoles; D009579:Nitrobenzoates; C096530:bis(1,3-dibutylbarbituric acid)pentamethine oxonol; D002034:Bumetanide; C058176:5-nitro-2-(3-phenylpropylamino)benzoic acid; D009544:Niflumic Acid; D005665:Furosemide; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid