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A biochemical difference between healthy bean leaves resistant and susceptible to the halo‐blight disease caused by Pseudomonas phaseolicola
Author(s) -
EPTON H. A. S.,
DEVERALL B. J.
Publication year - 1968
Publication title -
annals of applied biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.677
H-Index - 80
eISSN - 1744-7348
pISSN - 0003-4746
DOI - 10.1111/j.1744-7348.1968.tb04530.x
Subject(s) - phaseolus , biology , linolenic acid , linoleic acid , incubation , dry weight , botany , biochemistry , food science , fatty acid
SUMMARY Substrate for an endogenous oxidation in homogenates of leaves of bean ( Phaseolus vulgaris ) was traced to two fractions of lipids, each representing less than 2% of the dry weight of leaves. The substrate lipids, tentatively identified as galactosyl diglycerides, yielded linolenic and linoleic acids on acid hydrolysis. Amounts of linolenic acid in total lipids in resistant and susceptible leaves were similar. Amounts of free linolenic acid in resistant leaves increased eightfold to 408.6 μg and in susceptible leaves fourfold to 130.6 μg/g fresh leaf after homogenization and incubation for 16 min at 4 °C. These quantities are sufficient to account during their lipoxidation for the previously reported oxygen uptakes in homogenates. Differences between resistant and susceptible leaves were traced to the activities of lipase systems which liberate linolenic acid from substrate lipids.