Relation of membrane structural changes to energy spillover in oat and spinach chloroplasts: Use of fluorescence probes and light scattering

Abstract

SUMMARYThe antagonism observed by Gross and Hess (Gross, E. and Hess, S. C. (1973) Arch. Biochem. Biophys. 159,[832][833][834][835][836] in the effect of monovalent and divalent cations on energy spillover between Photosystems I and II, as indicated by chlorophyll a fluorescence, was confirmed in spinach. Significant differences with oats, peas and lettuce were found using the same low salt method of preparation: the response to Na + and Ca 2+ was reversible, Ca 2÷ alone, when added first, produced a large (85 %) increase in the variable portion of the chlorophyll a fluorescence transient or the steady-state fluorescence, and Ca 2 + not only fully restored a Na ÷ induced inhibition of 680 nm fluorescence, but brought it above the original level. The fluorescence probes 1-anilinonaphthalene-8-sulfonate and N-phenyl-l-naphthylamine showed a rapid and a slower response, respectively, to the addition of mono-or divalent cations. Neither the structural changes responsible for the probe data, nor those leading to the measured cation stimulated changes in 90 ° light scattering could be precisely equated with any alteration of conformation involved in the chlorophyll spillover events.

Cation‐induced changes in the circular dichroism spectrum of chloroplasts

“…The difference in response to cation addition between spinach and lettuce chloroplasts suggests differences in thylakoid stacking status between spinach and lettuce chloroplasts. This suggestion is consistent with the observations of VanderMeulen and Govindjee [10] on the response of chlorophyll a fluorescence yield and 90 ° light scattering to the addition of monovalent and divalent cations. The lettuce chloroplasts also exhibit a 3 nm red shift in the 683 nm positive CD peak upon the addition of divalent cations (cf.…”

The influence of cations and methylamine on structure and function of thylakoid membranes from barley chloroplasts

“…These include besides changes in structure (7,15,16,21,31,39,46), chloroplast lamellar volume (13,14,20,38,41,51) and light scattering properties (7,15,16,20,26,27,31,34,41,50) changes in chlorophyll absorption (15), fluorescence (9,11,12,15,16,19,24,26,27,(30)(31)(32)(33)(34)(35)50) and delayed light emission (4, 16,29,36). The 515-nm absorption change (13,16), the fluorescence of probes Abbreviations: BSA -bovine serum albumin, DCMU -3 (3,4-dichlorophenyl)-l,l-dimethyl urea, DBMIB -3-methyl-6-isopropyl-p-benzoquinone partitioned into chloroplast membrane lipids (16,31,50) and the size and distribution of large p...…”

Inorganic anions induce state changes in spinach thylakoid membranes

“…A decrease in Chl a £uorescence yield with low concentrations of NaCl was observed, but it was also interpreted as a Nainduced change [9]; similarly, a Na -induced decrease (at a concentration of 10 mM) in the fraction of quanta absorbed by PS II and a slight increase in the e¤ciency of excitation energy transfer from PS II to PS I was reported [10]. Low concentrations ( 6 10 mM) of monovalent cations were shown to produce an opposite e¡ect to that of Mg P or other divalent cations [11,12]. However, the role of anions was not recognised.…”