Transport of Cl- across the plasma membrane during pollen grain germination in tobacco

• Published in: Biochemistry (Moscow) 2003-11, Vol.68 (11), p.1247-1251
• Main Authors: Matveyeva, N P, Andreyuk, D S, Yermakov, I P
• Format: Article
• Language: English
• Subjects: 4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid - pharmacology; Antiporters - drug effects; Barbiturates - pharmacology; Bumetanide - pharmacology; Chloride Channels - antagonists & inhibitors; Furosemide - pharmacology; Germination - drug effects; Grain; Ion Transport - drug effects; Isoxazoles - pharmacology; Nicotiana - physiology; Niflumic Acid - pharmacology; Nitrobenzoates - pharmacology; Pollen; Pollen - physiology
• ISSN: 0006-2979; 1608-3040
• DOI: 10.1023/B:BIRY.0000009140.50032.3d

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.