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Peroxidase‐mediated chlorophyll bleaching in degreening canola ( Brassica napus ) seeds and its inhibition by sublethal freezing
Author(s) -
JohnsonFlanagan A. M.,
McLachlan G.
Publication year - 1990
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.1399-3054.1990.tb00067.x
Subject(s) - brassica , peroxidase , canola , enzyme , enzyme assay , horticulture , biochemistry , substrate (aquarium) , chemistry , biology , botany , ecology
Peroxidase activity in isolated thylakoids from degreening canola ( Brassica napus cv. Westar) seeds was demonstrated. The enzyme catalyzes the degradation of thylakoid‐bound pigments in the presence of H 2 O 2 and 2,4‐dichlorophenol. Peroxidase activity is related to degreening, with periods of rapid degreening associated with high enzyme activity. Both de novo synthesis and substrate availability appear to control enzyme activity. Peroxidase is initially inhibited and then stimulated by sublethal freezing. Therefore, inhibition of peroxidase activity following sublethal freezing may be responsible, in part, for a failure of the seed to degreen.