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Ecotoxicological information

Toxicity to terrestrial plants

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Description of key information

Ethylene is a natural plant hormone, affecting a wide range of reactions in vascular plants. There is a wealth of literature available on the effect of ethylene on plants.

Key value for chemical safety assessment

Additional information

The results have been taken from published, non-GLP, non-guideline papers, which all follow sound scientific principles and include

sufficient description of the procedure to assess the data as valid. The studies tested a variety of plants over a range of time periods, under strict conditions with analytical monitoring and control groups. The studies are considered reliable and suitable for use for this endpoint.

Dueck (2002) showed ethylene concentrations of up to 800 ppb, administered 4 times per week for 3 hours during the growing season, did not affect vegetative growth and yield in the exposed potato plants. Plants exposed to discontinuous exposures of ethylene outdoors are given ample time for recovery and possible compensation.

Morgan (1973) showed that for each plant age there was a region of maximum sensitivity to ethylene, generally the first partially expanded leaf and those above it, then a second region at the base of the plant and moved upward with time. The effect was most pronounced in the oldest plants and higher ethylene level.

Elmo (2009) showed an increase in leaf abscission and reduced capacity to transport auxin in plants exposed to 14 ul/L of ethylene for 24 or 48 hours. Effects increased with increased temperature and were reduced with auxin pretreatment. The auxin transport system showed full recovery in cotton plants, but only significant recovery in beans, with recovery level dependent on ethylene concentration.

Abeles (1968) showed half-maximum stimulation of abscission at approximately 0.1 ppm ethylene. Abscission of the plants was blocked by carbon dioxide, though the effect could be reversed by simultaneous addition of ethylene, though oxygen had no observable effect on ethylene production.

Tonneijck (2003) showed in plants exposed to a growing season mean of 62 ug ethylene/m3 that flowering was stimulated and growth was not affected. Adverse effects were observed to diminish with distance to 870m from the emission sources, though growth reduction was more sensitive than flowering inhibition.