The Metabolism of Oat Leaves during Senescence: IV. The Effects of alphaalpha'-Dipyridyl and other Metal Chelators on Senescence.
The senescence of the first leaves of light-grown Avena seedlings when detached and placed in the dark is inhibited by alpha, alpha'-dipyridyl and alpha, alpha', alpha''-tripyridyl at concentrations between 10(-5) and 10(-4) M. Five other chelating agents exert similar inhibiting effects at concentrations 3 to 30 times higher. The senescence of etiolated leaves, as shown by loss of carotenoid and protein, is similarly inhibited. Ethylene-diaminetetraacetate has a similar effect in the dark, though only at 10 mM and above, but in the light it causes bleaching of chlorophyll. It is deduced that an iron-containing system plays an essential part in the initiation of the senescence process.
Tetley
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The Thimann Laboratories, Division of Natural Sciences, University of California, Santa Cruz, California 95064.
Thimann
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