Journalartikel

Jahr der Veröffentlichung: 1991

Seiten: 105-112

Zeitschrift: Planta

Bandnummer: 184

Heftnummer: 1

ISSN: 0032-0935

Verlag: Springer

Abstract: 
The fluorescent calcium-sensitive dye 1-[2-amino-5-(6-carboxyindol-2-yl)-phenoxy]-2-(2'-amino-5'-methylphenoxy)-ethane-N,N,N',N'-tetraacetic acid (in-do-1) was loaded by a transplasmalemma pH gradient into filamentous cells and protoplasts of Mougeotia scalaris, such that most of the indo-1 fluorescence originated from the cytoplasm. Incubation of M. scalaris filaments in ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA)-buffered media (- log [Ca2+] (= pCa) 8 versus pCa 3) caused a consistent and significant decrease in the cytoplasmic free [Ca2+]. Pulses of the fluorescence excitation light (UV-A 365 nm, 0.7 s) caused an increase in cytoplasmic free [Ca2+] in M. scalaris that was nearly independent of the external [Ca2+] and of chloroplast dislocation by centrifugation. This calcium flux, highest in UV-A light, compared with blue or red light, probably resulted from a release of Ca2+ from intracellular stores. Increased cytoplasmic [Ca2+] may affect the velocity of chloroplast rotation since UV-A-light-mediated chloroplast movement was faster than in blue or red light. Consistently, the calcium ionophore A23187 and the calcium-channel agonist Bay-K8644 both increased the velocity of the red-light-mediated chloroplast rotation. Based on these and other observations, a Ca2+ -induced decrease in cytoplasmic viscosity in Mougeotia is presumed to occur.

Harvard-Zitierstil: RUSS, U., GROLIG, F. and WAGNER, G. (1991) CHANGES OF CYTOPLASMIC FREE CA2+ IN THE GREEN-ALGA MOUGEOTIA-SCALARIS AS MONITORED WITH INDO-1, AND THEIR EFFECT ON THE VELOCITY OF CHLOROPLAST MOVEMENTS, Planta, 184(1), pp. 105-112

APA-Zitierstil: RUSS, U., GROLIG, F., & WAGNER, G. (1991). CHANGES OF CYTOPLASMIC FREE CA2+ IN THE GREEN-ALGA MOUGEOTIA-SCALARIS AS MONITORED WITH INDO-1, AND THEIR EFFECT ON THE VELOCITY OF CHLOROPLAST MOVEMENTS. Planta. 184(1), 105-112.