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The Photostability of Different Chlorophyll Forms in Dark Grown Leaves of Wheat
Author(s) -
AXELSSON LENNART
Publication year - 1976
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1976.tb04015.x
Subject(s) - chlorophyll , pigment , protochlorophyllide , kinetics , chlorophyll a , irradiation , photochemistry , photosynthesis , chemistry , botany , biology , chloroplast , biochemistry , organic chemistry , physics , quantum mechanics , nuclear physics , gene
Abstract The stability against high intensity irradiation (red light, 700 W m −2 ) was investigated for the chlorophyll(ide) pigments formed after photoreduction of the protochlorophyllide of dark grown leaves of wheat. The reaction kinetics for the photodecomposition of the 673‐form was the same as for photooxidation of chlorophyll in vitro, which is a second order reaction with respect to the chlorophyll concentration. The 684‐form was photodecomposed in a first order reaction. This deviation from the in vitro kinetics may be explained by a gradual ‘decrease’ in the photostability of the pigment during the irradiation, possibly dependent on a gradual increase in the internal concentration (‘aggregation’) of the pigment. The photo‐stability was found to be 4–5 times higher for the 673‐form than for the 684‐form (the half‐lives were 10.5 and 2.3 min respectively). Connections between the presence of photosynthetic activity and the reaction kinetics for the photodecomposition of the chlorophyll(ide) are discussed.