Paper
Ethylene evolution from 2-chloroethylphosphonic Acid.
Published 1969 · H. L. Warner, A. Leopold
Plant physiology
159
Citations
9
Influential Citations
Abstract
Strong growth regulating properties have been observed for 2-chloroethylphosphonic acid (Amchem 66-329) when applied to plants, and the regulatory effects have been attributed to the liberation of ethylene within plants (5). Many regulatory effects of this chemical resemble the effects of ethylene, including the induction of ripening in bananas and tomatoes (4), flowering in pineapple, and abscission and various epinastic responses (1). The present report provides evidence that 2-chloroethylphosphonic acid (CEPA) breaks down in the presence of a base to form ethylene with an apparent release of chloride and phosphonate. To illustrate the decomposition reaction, 5 ml of CEPA at 2 X 10-4 M in a 1000 ml reaction flask, with either NaOH (8 X 10-4 M) or 500 mg of etiolated pea epicotyls, evolve ethylene as shown in figure 1. The production of ethylene occurs not only in the presence of the plant tissue, but also in the presence of added base. In this experiment 1.0 jumole of CEPA was present initially and 0.98 ,tmole of ethylene had been produced 48 hr after addition of NaOH, indicating essentially complete conversion of the CEPA to ethylene. The logarithmic type of time curve in the presence of added base suggests a second-order reaction, possibly involving the alkali in reaction with CEPA. The rate of the reaction is increased by higher levels of added alkali. That the gas involved is ethylene was determined by gas chromatography (2) and its identity was confirmed by reaction with mercury perchlorate (6). The gas chromatographic peak considered to be ethylene was 99.2 % removed by introduction into the reaction flask of a paper wick moistened with Hg(C104)2. The decomposition of CEPA to ethylene should bring about the release of phosphonate and chloride. As an indication of phosphonate formation, in a test run concurrently with the experiment in figure 1 phosphate was measured by Allen's molybdate color test, assuming a fairly ready oxidation of the phos-
Highly Cited2-chloroethylphosphonic acid (CEPA) can break down in the presence of a base to form ethylene, potentially releasing phosphonate and chloride, potentially affecting plant growth and development.
Full text analysis coming soon...