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'Chloroplast Ultrastructure' in keywords Facet   section ZfN Section C  [X]
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1Author    H. K. Lichtenthaler, G. Kuhn, U. Prenzel, C. Buschmann, D. MeierRequires cookie*
 Title    Adaptation of Chloroplast-Ultrastructure and of Chlorophyll- Protein Levels to High-Light and Low-Light Growth Conditions  
 Abstract    Adaptation In saturating light radish seedlings grown in high-light growth conditions (90 W • n r 2) possess a much higher photosynthetic capacity on a chlorophyll and leaf area basis than the low-light grown plants (10 W • m-2). The higher C 0 2-fixation rate o f HL-plants is due to the presence of HL-chloroplasts which possess a different ultrastructure and also different levels o f the individual chlorophyll-carotenoid-proteins than the LL-chloroplasts of LL-seedlings. 1. Ultrastructure: The high-light adapted chloroplasts are characterized by fewer photo­ synthetic membranes per chloroplast section, by low grana stacks (only few thylakoids per granum), a lower stacking degree o f thylakoids, a higher proportion o f non-appressed mem­ branes (stroma thylakoids + end grana membranes) and a high starch content. The LL-chloro­ plasts possess no starch, their grana stacks are higher (up to 17 thylakoids per granum) and also significantly broader than that o f HL-chloroplasts. 2. Chlorophyll-proteins: The photosynthetic apparatus o f HL-chloroplasts contains a larger proportion of chlorophyll a-proteins of photosystem I (CPIa + CPI) and of photosystem II (CPa, the presumable reaction center o f PS II) than the LL-chloroplasts which possess a higher propor­ tion of light-harvesting chlorophyll a/fc-proteins (LHCP,, LHCP2, LHCP3, LHCPy). The higher levels of LHCPs in LL-plants are associated with a higher ground fluorescence fo and maximum fluorescence fp of the in vivo chlorophyll. 3. Chlorophyll and carotenoid ratios: The chloroplasts o f HL-plants possess a higher proportion of chlorophyll a and /2-carotene (higher values for the ratios chlorophyll a /b and lower values for a/c and x /c) which reflect the increased level o f the chlorophyll a//?-carotene-proteins CPIa, CPI and CPa. The higher level o f light-harvesting chlorophyll a/6-xanthophyll-proteins (LHCPs) in LL-plants is also indicated by an increased content o f xanthophylls and chlorophyll b as seen from lower a /b and higher x /c and a /c ratios. 4. The results indicate that plants possess the capacity for an ontogenetic adaptation o f their photosynthetic apparatus to the incident light intensity. The HL-chloroplasts o f HL-plants which contain less antenna chlorophyll, are adapted for a more efficient photosynthetic quantum conversion at light saturation than the LL-chloroplasts with high grana stacks. The correlation between higher levels o f light-harvesting chlorophyll ö/6-proteins (LHCPs) and a higher stacking degree of thylakoids, and the involvement o f LHCPs in stacking is discussed. Abbreviations: a/b, ratio chlorophyll a/b', a /c, weight ratio chlorophyll a to /^-carotene, CPI and CPIa, the two P700 containing chlorophyll a /?-carotene-proteins o f photosys­ tem I; CPa, chlorophyll a /?-carotene-protein o f photosys­ tem II, c/x, ratio /?-carotene/xanthophylls; fo, ground fluo­ rescence of the in vivo chlorophyll fluorescence; fp, maxi­ mum level of the in vivo chlorophyll fluorescence; FP, free pigments; HL, high-light growth condition; LHCPs, sum of the 4 light-harvesting-chlorophyll a/6-proteins L H C P,, LHCP2, LHCP3 and LHCPy; LL, low light growth condi­ tion; PAGE, polyacrylamide-gel electrophoresis; PS I and PS II photosynthetic photosystem I and II; SDS, sodium dodecylsulphate; Tris, tris (hydroxymethyl)-aminomethan; v/v, volume per volume; w/v, weight per volume; x/c, weight ratio xanthophylls to /7-carotene. * The work described here, was presented on the European Symposium Light Mediated Plant Development in April 1981 in Bischofsmais, Bavaria. 
  Reference    Z. Naturforsch. 37c, 464 (1982); received March 2 1982 
  Published    1982 
  Keywords    of Chloroplasts, Chlorophyll Fluorescence, Chlorophyll a-Proteins, Chloroplast Ultrastructure, High-Light Chloroplasts 
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 TEI-XML for    default:Reihe_C/37/ZNC-1982-37c-0464.pdf 
 Identifier    ZNC-1982-37c-0464 
 Volume    37