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Phenolic acids associated with the resistance of lettuce cultivars to the lettuce root aphid
Author(s) -
COLE ROSEMARY A.
Publication year - 1984
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.1744-7348.1984.tb02809.x
Subject(s) - cultivar , polyphenol oxidase , phenylalanine ammonia lyase , biology , aphid , browning , catechol oxidase , high performance liquid chromatography , botany , horticulture , polyphenol , food science , phenylalanine , enzyme , antioxidant , peroxidase , chemistry , chromatography , amino acid , biochemistry
SUMMARY Phenolic acids, particularly caffeoylquinic acids, in lettuce root extracts were analysed by high pressure liquid chromatography (hplc), gas liquid chromatography (glc) and ultra‐violet (uv) absorbance to seek a relationship with the resistance of certain lettuce cultivars to lettuce root aphid, Pemphigus bursarius. Although consistent results were obtained by each method, glc estimates of isochlorogenic acid tended to be low and uv estimates high. Hplc results were intermediate and since it was the easiest technique to perform routinely it was preferred. Isochlorogenic acid was the only caffeoylquinic acid detected in quantity and there were greater concentrations in resistant than in susceptible cultivars. Phenylalanine‐ammonia lyase (PAL), the first enzyme in the phenyl propanoid pathway, is more active in resistant cultivars. Although these cultivars also had a greater tendency to browning when damaged, it was not due to greater polyphenol oxidase activity but probably to the presence of more isochlorogenic acid substrate. The results were consistent with an association between isochlorogenic acid concentration, PAL activity and resistance to P. bursarius.