Electrochromism of chlorophylls and carotenoids in multilayers and in chloroplasts

TLDR: The influence of an electric field on the absorpt ion spectra (electrochromism) of chlorophyll and carotenoid multi layers bui l t up on slides has been measured and the spectrum of the light-induced field-indicating absorption changes of spinach chloroplasts is shown.

Abstract: Some of the l ight-induced t ransient changes in the absorpt ion of chloroplasts are though t to be due to a l ight-induced electric field which alters the absorpt ion spectra of the bulk pigments in the photosynthet ic membrane [t, 2]. In order to tes t this interpretat ion, the influence of an electric field on the absorpt ion spectra (electrochromism) of chlorophyll and carotenoid multi layers bui l t up on slides has been measured [3-5]. The spectrum of the light-induced field-indicating absorption changes of spinach chloroplasts as published in [2] is shown in Fig. t top. The spectra of the electrically induced absorption changes of a) chlorophyll a, b) chlorophyll b, and c) carotenoids are shown in Fig. I bot tom. The spectrum c) is a superposition of the electrochromic spectra of hitein, t -carot in , violaxanthin, and neoxan th in in their na tura l molar ratio. The electrochromic spectrum of lutein has been measured directly; the