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

Pathways of cadmium fluxes in the root of the halophyte Suaeda salsa

“…SIET has been reported to be an effective technique in measuring the flux of ions, such as nutrient elements Ca 2 þ (Wang et al, 2009) Sun et al, 2009a, b), Cl À (Zonia et al, 2002), and the trace metal ion Cd 2 þ (Pineros et al 1998;Leonard et al 2009;Ma et al, 2010). SIET provides researchers with a new approach to study ion uptake and accumulation in plants and animals under normal .…”

Metabolic and signaling properties of an Itpk gene family in Glycine max

“…We now report that the three other GmItpk isoforms also show this activity: type 1 = 403 ± 4, type 3 = 487 ± 47, type 4 = 88 ± 16 (lmol/ mg protein/min), albeit at rates 6-to 33-fold lower than that of the type 2 enzyme. Substrate cycling between Ins(3,4,5,6)P 4 and Ins(1,3,4,5,6)P 5 may serve a signaling role in plants, in which Ins(3,4,5,6)P 4 has been shown to regulate Cl À channel conductance [15], similar to the role of Ins(3,4,5,6)P 4 in animal cells [22].…”

Exclusion of a Proton ATPase from the Apical Membrane Is Associated with Cell Polarity and Tip Growth inNicotiana tabacumPollen Tubes

“…An ion-selective vibrating electrode (Kü htreiber and Jaffe, 1990;Shipley and Feijó , 1998;Feijó et al, 1999) was used to measure extracellular H þ fluxes in pollen tubes generally as described by Zonia et al (2002). To build the H þ -specific electrode, 1.5-mm borosilicate glass electrodes (tip diameter 1 to 3 mm) were covered with N,N-dimethyltrimethylethylsilamine (Fluka), backfilled with a 10-to 20-mm column of 40 mM KH 2 PO 4 /15 mM KCl, pH 6.0, and front-loaded with a 25-mm column of a H þ -selective liquid exchange cocktail (Hydrogen Ionophore Cocktail B; Fluka).…”

“…As early as 1975, Weisenseel et al identified the germinated pollen grain as an electric dipole with the grain functioning as a source of a cationic current, that is, cations leave the grain and enter at the tip. It has recently been established that at least Ca 2þ , H þ , K þ , and Cl À are part of this current and that their extracellular fluxes are conspicuously polarized, presumably by polarization of their underlying transporters (Holdaway-Clarke et al, 1997;Feijó et al, 1999;Messerli et al, 1999;Zonia et al, 2001Zonia et al, , 2002. Internal apically polarized gradients of Ca 2þ and H þ have been correlated with the growth properties of these cells (Feijó et al, 1995(Feijó et al, , 1999HoldawayClarke et al, 1997;Messerli et al, 1999;reviews in Feijó et al, 2004;Boavida et al, 2005b).…”