Characterization of two phases of chlorophyll formation during greening of etiolated barley leaves.
The esterification kinetics of chlorophyllide, obtained by a single flash of light, were investigated in etiolated barley ( Hordeum vulgare L.) and oat ( Avena sativa L.) leaves. A rapid phase, leading to esterification of 15% of total chlorophyllide within 15-30 s, was followed by a lag-phase of nearly 2 min and a subsequent main phase, leading to esterification of 85% of total chlorophyllide within 30-60 min. The presence of additional protochlorophyllide, produced in the leaves by incubation with 5-aminolevulinate, did not change the esterification kinetics. The rapid phase was identical after partial (11-15%) and full (>80%) photoconversion of protochlorophyllide; the ability for a second rapid esterification phase was restored in a dark period of at least 10 min. Cooling the leaves to 0 degrees C abolished the esterification of the main phase while the rapid phase remained unchanged. The prolamellar bodies were already in part transformed into prothylakoid-like structures within 2-5 min after a full flash but not after a weak flash (11% photoconversion); in the latter case, the corresponding transformation required a dark period of about 45 min. The existence of subcomplexes of prolamellar bodies containing NADPH:protochlorophyllide oxidoreductase and chlorophyll synthase in the ratio 7:1 is discussed.
Domanskii
Vladimir
V
Institute of Photobiology of the National Academy of Sciences of Belarus, Akademicheskaya 27, 220072 Minsk, Belarus.
Rassadina
Valentina
V
Gus-Mayer
Sabine
S
Wanner
Gerhard
G
Schoch
Siegrid
S
Rüdiger
Wolfhart
W
D000622:Aminolevulinic Acid / Q000378:metabolism; D018554:Avena / Q000378:metabolism; D019729:Carbon-Oxygen Ligases / Q000378:metabolism; D002734:Chlorophyll / Q000096:biosynthesis*; D002735:Chlorophyllides / Q000378:metabolism; D001467:Hordeum / Q000378:metabolism* / Q000528:radiation effects; D008027:Light; D008854:Microscopy, Electron; D009249:NADP / Q000378:metabolism; D010088:Oxidoreductases / Q000378:metabolism; D044925:Oxidoreductases Acting on CH-CH Group Donors; D010860:Pigments, Biological / Q000378:metabolism; D018515:Plant Leaves / Q000378:metabolism* / Q000528:radiation effects; D020524:Thylakoids / Q000378:metabolism / Q000648:ultrastructure; D013997:Time Factors
D002735:Chlorophyllides; D010860:Pigments, Biological; D002734:Chlorophyll; D009249:NADP; D000622:Aminolevulinic Acid; D010088:Oxidoreductases; D044925:Oxidoreductases Acting on CH-CH Group Donors; C023886:protochlorophyllide reductase; D019729:Carbon-Oxygen Ligases; C026901:chlorophyll synthetase