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Movement of diquat (1,1'‐ethylene‐2,2'‐bipyridylium) dibromide in leguminous plants
Author(s) -
THROWER STELLA L.,
HALLAM N. D.,
THROWER L. B.
Publication year - 1965
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.1744-7348.1965.tb07939.x
Subject(s) - diquat , transpiration , xylem , biology , botany , movement (music) , desiccation , horticulture , paraquat , biochemistry , photosynthesis , philosophy , aesthetics
SUMMARY In studies on movement of diquat dibromide (1,1'‐ethylene‐2,2'‐bipyridylium dibromide) in broad bean, french bean and soybean, discoloration of tissues was used as an indication of its presence. The presence of cuticular wax on leaves interfered with the entry of diquat. Movement of diquat within the plant occurred readily in either light or darkness. Ringing experiments showed that movement took place predominantly in the xylem, and defoliation experiments indicated that movement was associated with the transpiration stream. In light, movement of diquat in the plant occurred when the relative humidity was near 100% but was markedly less than that occurring at 50% r.h . High temperature and low humidity promoted rapid drying of treated leaves which confined the diquat to these leaves and prevented movement to untreated parts of the plant. In stems diquat moved from the xylem to the outer cortical parenchyma; cell‐to‐cell diffusive movement also occurred in leaves. Movement of diquat in the plant is shown to be a sequential process, the part responsible for most extensive distribution being movement in the transpiration stream. Therefore, conditions which favour transpiration (without undue desiccation) will promote movement of diquat.