[Fluorescence, chlorophyll shape and number of photosystem reaction centers I and II in chlorotica mutants of Pisum sativum L].
The fluorescent and absorbing properties of chloroplasts and pigment-protein complexes isolated by gel electrophoresis from pea leaves of the cultivar Torsdag and the mutants chlorotica 2004 and 2014 were studied. From the absorption and fluorescence spectra of chlorophylls and their 2nd derivatives, the range of their changes in the native state at 23 degrees C and specific maxima of fluorescence and the forms of chlorophyll of individual complexes at -196 degrees C were found. It was found that in mutant chlorotica 2004 the intensity of fluorescence of long-wave band at 745 nm (23 degrees C) and the maximum--at 728 nm (-196 degrees C) belonging to the light-harvesting complex I increased. Nevertheless, the accumulation of the chlorophyll forms in this mutant at 690, 697 and 708 nm, which make an antenna of reaction centers of photosystem (PS) I decreased. No spectral differences from the spectrum of the wild type were found in mutant chlorotica 2014, except for a weakening of interaction between the complexes of PS I and PS II. It was shown by gel electrophoresis that both mutants were capable of synthesizing any chlorophyll-protein complexes. However, the analysis of the photochemical activity of reaction centers of PS I and PS II as well as calculations of the value of the photosynthetic unit and the number of reaction centers of the photosystems enabled us to conclude that the quantity of the reaction centers of PS I in the mutant chlorotica 2004 was 1.7 times lower due to disturbance of mutations in biosynthesis or the formation of the chlorophyll a-protein complex of PS I. No primary effect of mutation of chlorotica 2014 was established. Proportional changes of all parameters in this mutant gave us the ground to consider them as secondary ones, which are caused by a decrease in chlorophyll content by half.
Ladygin
V G
VG
Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino, Moscow Region, 142290 Russia.
D002734:Chlorophyll / Q000737:chemistry*; D045342:Light-Harvesting Protein Complexes; D009154:Mutation; D018532:Pisum sativum / Q000737:chemistry* / Q000235:genetics / Q000648:ultrastructure; D045322:Photosynthetic Reaction Center Complex Proteins / Q000737:chemistry*; D018515:Plant Leaves / Q000737:chemistry / Q000648:ultrastructure; D013050:Spectrometry, Fluorescence
D045342:Light-Harvesting Protein Complexes; D045322:Photosynthetic Reaction Center Complex Proteins; D002734:Chlorophyll