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METABOLISM OF PLANT GROWTH REGULATORS
Author(s) -
LUCKWILL L. C.,
LLOYDJONES C. P.
Publication year - 1960
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.1744-7348.1960.tb03564.x
Subject(s) - decarboxylation , biology , metabolism , botany , horticulture , seedling , plant metabolism , biochemistry , gene , catalysis , rna
Comparison of the metabolism of 14 C carboxyl‐labelled 2,4‐D in detached leaves of different varieties of apple showed that the 2,4‐D‐resistant Cox decarboxylated 57% of the 2,4‐D in the leaf in 92 hr., whereas the susceptible Bramley's Seedling decarboxylated only 2% in the same time. Comparatively high rates of decarboxylation were found with all varieties of apple having Cox in their parentage; varieties unrelated to Cox showed low rates of decarboxylation. Similar high rates of decarboxylation were found in resistant varieties of strawberry and in Syringa vulgaris. Sixteen other species tested showed low rates of decarboxylation, irrespective of whether they were resistant or susceptible to 2,4‐D. The rate of decarboxylation of 2,4‐D in the mature strawberry leaf was proportional to the amount of 2,4‐D in the leaf. The rapid fall in decarboxylation rate in a detached leaf was due chiefly to reduction in the amount of 2,4‐D present, and not to any falling off in the metabolic activity of the leaf. Young leaves decarboxylated 2,4‐D at about half the rate of fully grown or senescent leaves. Oxidation of the methylene carbon proceeds at less than half the rate of that of the carboxyl carbon and is accompanied by an increase in the phenol content of the leaf which agrees closely with the amount of 2,4‐D demethylated. As previously reported for currants, part of the 2,4‐D entering the leaf was bound and part inactivated by the formation of water‐soluble compounds. The reaction of strawberry variety Talisman to 2,4,5‐trichlorophenoxyacetic (2,4,5), 2‐chloro‐phenoxyacetic (2‐CPA), 4‐chlorophenoxyacetic (4‐CPA) and 2‐methyl‐4‐chlorophenoxyacetic (MCPA) acids was similar to that previously reported for red currant. Leaves of Cox's Orange Pippin apple and Talisman strawberry were able to decarboxylate all these phenoxy‐acids except 2‐CPA.