Spatio-temporal patterns of photosystem II activity and plasma-membrane proton flows in Chara corallina cells exposed to overall and local illumination

• Published in: Planta Vol. 218; no. 1; pp. 143 - 151
• Main Authors: Bulychev, Alexander, Vredenberg, Wim
• Format: Journal Article
• Language: English
• Published: Berlin Springer-Verlag 01.11.2003; Springer; Springer Nature B.V
• Subjects: Acids; algae; basic zones; buffers; Cell Membrane; Cell Membrane - metabolism; Cell Membrane - radiation effects; Cell membranes; Cell walls; Chara; Chara - metabolism; Chara - radiation effects; Chara corallina; chlorophyll-a fluorescence; Chlorophylls; Chloroplasts; Darkness; Fluorescence; Heterogeneity; Hydrogen-Ion Concentration; internodal cells; k+ channel; Kinetics; Light; metabolism; nitella; oscillations; Photochemicals; Photosynthesis; photosynthetic activity; photosystem II; Photosystem II Protein Complex; Photosystem II Protein Complex - metabolism; Photosystem II Protein Complex - radiation effects; physiological transport; Plant cells; plasma membrane; Protons; radiation effects; Time Factors; transport
• ISSN: 0032-0935; 1432-2048
• DOI: 10.1007/s00425-003-1084-6

Pulse-amplitude modulated microfluorometry and an extracellular pH microprobe were used to examine light-induced spatial heterogeneity of photosynthetic and H+-transporting activities in cells of Chara corallina Klein ex Willd. Subcellular domains featuring different PSII photochemical activities were found to conform to alternate alkaline and acid zones produced near the cell surface, with peaks of PSII activity correlating with the position of acid zones. Buffers eliminated pH variations near the cell surface but did not destroy the variations in PSII photochemical yield ($\mathrm{\Delta }\mathrm{F}/{\mathrm{F}}_{\mathrm{m}}^{\prime }$). When a dark-adapted cell was exposed to actinic light, the PSII effective yield decreased within 5—15 min in the alkaline regions but rose after the initial decline in the acid regions. The light-induced decrease in $\mathrm{\Delta }\mathrm{F}/{\mathrm{F}}_{\mathrm{m}}^{\prime }$ in the alkaline regions occurred prior to or synchronously with the steep rise in local pH. The kinetics of $\mathrm{\Delta }\mathrm{F}/{\mathrm{F}}_{\mathrm{m}}^{\prime }$, ${\mathrm{F}}_{\mathrm{m}}^{\prime }$, and F observed in alkaline regions under overall illumination of Chara cells were replaced by those typical of acid regions, when the illumination area size was restricted to 1.5—2 mm. The data show that photoinduced patterns in photosynthetic activity are not predetermined by the particular structural organization of alkaline and acid cell regions but are subject to dynamic changes.