Photosynthesis-inhibiting Effects of Cationic Biodegradable Gemini Surfactants

Abstract

Abstract Cationic biodegradable gemini surfactants 3,8-diaza-4,7-dioxodecane-1,10-diylbis(alkyldimethylammonium bromide) (I) with R = C9H19–C18H37 inhibited photosynthetic electron transport (PET) in spinach chloroplasts and reduced chlorophyll (Chl) content in Chlorella vulgaris. The inhibitory effects of I intensively depended on the length of alkyl chain showing quasi-parabolic (Chlorella vulgaris) or bilinear (PET) course. IC50 value related to reduction of Chl content in C. vulgaris for dodecyl derivative was 0.6 × 10−6 mol dm−3 indicating its strong anti-algal effect. Using EPR spectroscopy as the site of inhibitory action of I in the photosynthetic apparatus the intermediates Z∗ and D∗ or their close surroundings were determined. As a further target of I inhibitory action the manganese cluster occurring on the donor side of photosystem II was estimated.