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THE ABSORPTION, BREAKDOWN AND SYSTEMIC BEHAVIOUR IN PLANTS OF 32 P‐LABELLED DEMETON‐S
Author(s) -
THOMAS W. D. E.,
BENNETT S. H.,
LLOYDJONES C. P.
Publication year - 1955
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.1744-7348.1955.tb02505.x
Subject(s) - xylem , phloem , biology , shoot , botany , absorption (acoustics) , horticulture , agronomy , physics , acoustics
Investigations are described on the general behaviour of diethyl‐5‐(a‐ethylthioethyl) phosphorothiolate (demeton‐S) labelled with 32 P, after leaf application to beans, apples and Coleus ; and to the roots of beans growing in soil or sand. Following leaf application, three processes, evaporation, breakdown into toxic non‐volatile compounds, and absorption, occurred concurrently and effectively removed unchanged demeton‐S from the leaf surface within a few hours. The evaporation gave rise to a fumigant action on Aphis fubue. Both demeton‐S and its degradation products were absorbed, the former degrading rapidly within the tissue untreated foliage. In no instance following leaf application could any unchanged demeton‐S be found elsewhere in the plant. Analyses showed a higher proportion of primary toxic degradation products in the treated than in the untreated leaves. Translocation from treated leaves was never sufficient to kill aphids feeding on the Following root application to beans in soil or sand, aphids feeding on the shoot tips were killed after z days; unchanged demeton‐S was translocated following root application. Demeton‐S and its toxic derivatives appeared to move much more freely in xylem than in phloem tissue; movement from xylem to phloem must occur, but subsequent transport within the latter tissue is limited. Autoradiographic evidence confirmed the limited extent of movement within leaves.